FIELD OF INVENTION The present invention relates generally to a process for treating palm oil mill effluent. More particularly, to a process for treating palm oil mill effluent using electro-oxidation process.

BACKGROUND

Processing of oil palm fresh fruit bunches (FFB) in a palm oil mill for the production of palm oil creates a type of polluted wastewater known as palm oil mill effluent (POME). 3 major operations of the milling process namely sterilization of the FFB, clarification step and pressing of the empty fruit bunches (EFB) uses large quantities of water, whereby at least 50% of the water results in POME. POME is a source of inland water pollution (due to its high chemical oxygen demand (COD), biochemical oxygen demand (BOD) and its acidic nature) and hence is not allowed to be discharged into bodies of water (i.e. rivers / lakes) without being treated for discharge into the environment according to be in compliance with environmental standards as set by the authorities.

Typically, 5 to 7.5 tonnes of water are required for production of 1 tonne of crude palm oil (CPO), whereby 50% ends up as POME. POME is a viscous, brownish liquid containing about 95%-96% water, 0.6%-0.7% oil and 4%-5% total solids. POME is acidic in nature (pH 4 to 5), hot (80-90 °C), non-toxic (as no chemicals are added during the CPO extraction process in the palm oil mill) and has high COD (50,000 mg/L) and BOD (25,000 mg/L) contents and also contains certain amounts of nutrients. [Source: Palm Oil Mill Effluent (POME) Treatment 'Microbial Communities in an Anaerobic Digester”: A Review, International Journal of Scientific & Research Publications] Discharging untreated POME into bodies of water depletes dissolved oxygen (oxygen as present in the water) as bacteria breaks down the organic materials in POME in natural systems which consumes certain amounts of oxygen in the process. If organic material is high, hence, the breakdown process will diminish the levels of oxygen in the water which would be lethal for the aquatic organisms, f Source: Handbook POME-to-Biogas, Project Development in Indonesia] POME is without a doubt the largest waste generated from the CPO extraction process. Anaerobic digestion has been used by most of the palm oil mills as the primary treatment of POME and the secondary treatment of POME is generally the assimilation with the blend of both anaerobic and aerobic ponds. Anaerobic digestion is considered as the most suitable POME treatment method as because of its high concentration of organic carbon. Most of the palm oil mills uses open ponding system for POME treatment due to the low costs involved and operational simplicity, which generally consists of four types of ponds namely the fat pit, cooling pond, anaerobic pond and aerobic pond. Although ponding systems are largely used by the industry due to economic perspective, however, it is land and time intensive (i.e, requires long retention times and large treatment areas) and also release large amount of methane gas into the atmosphere.

Anaerobic digestion is a collection of processes wherein bacteria breakdown organic biomass without the presence of oxygen. Examples of resulting products of anaerobic digestion are methane and carbon dioxide. These biogas products can be used directly for fuel, e.g, in heat and power gas engines, or converted to other forms of renewable energy, e.g. natural gas. The process of anaerobic digestion typically begins with bacterial hydrolysis of the input materials. Insoluble organic polymers, e.g. carbohydrates, are broken down to soluble derivatives that become available for other bacteria. Acidogenic bacteria then convert the soluble derivatives, e.g. sugars and amino acids, into carbon dioxide, hydrogen, ammonia, and short chain fatty acids (also known as “volatile fatty acids” or VFA). Finally, methanogenic bacteria, or methanogens, convert the VFA to methane and carbon dioxide. In some processes, an intermediate step called acetogenesis occurs where the acidogenic bacteria convert VFAs into acetic acid, which the methanogens utilize in the production of methane and carbon dioxide. [Source: United States Application US 10233104B2 ]

A publication entitled “A Review on the Development of Palm Oil Mill Effluent (POME) Final Discharge Polishing Treatments” [Source: Journal of Oil Palm Research Vol. 29(4) December 2017] describes that conventional ponding systems generally consist of cooling and mixing, anaerobic, facultative and aerobic ponds. Cooling and mixing ponds serves to stabilise the POME temperature and pH prior to anaerobic digestion. Anaerobic stage produces methane gas which is a value added produce for biogas. Facultative and aerobic ponds are necessary to further reduce the organic content in the wastewater before it is discharged to the rivers. Open ponding system has been proven to successfully reduce the concentration of pollutants such as COD (100-175 mg/L), BOD (100-610 mg/L) and ammoniacal nitrogen (100-200mg/L). This system requires long total hydraulic retention time between 45 to 60 days and large land area. The last few years have seen a major shift towards sustainability from conventional treatments of POME to tertiary treatments using various technologies. Recently the research interest seems to have shifted to the development of sustainable polishing technologies. Previous studies have proven that palm-based bio-adsorbents have great potential to remove residual organic pollutants, heavy metals and colour from POME. Adsorption treatment on POME final discharge of polishing system results in higher pollutant removal compared with the adsorption treatment of POME from the ponding system. The maximum colour and COD reduction of POME final discharge were 98% and 81%, respectively.

Wastewater treatment solution POMETHANE® by Veolia is an anaerobic mesophilic and thermophilic digestion process which maximizes the yield of biogas production and offers an attractive solution for the treatment of high concentrated and hot effluent streams. Veolio states that with POMETHANE® combined with an aerobic polishing plant is able to achieve a final effluent discharge of BOD < 20ppm. [Source: Veolia Water Technologies]

Raw POME has a BOD which is about one hundred times more than that of sewage. If not properly treated, POME could pose as a high organic pollutant. Conventional ponding process has been an effective method to reduce the biological and chemical constituents of POME. This method, even though simple and reliable, generates large amounts of sludge and takes up large land areas. It is thus justifiable that many studies have been conducted to develop alternative methods for POME treatment with possibilities of resource recovery by smaller, higher efficiency treatment system. Membrane technology has high potential of becoming part of POME treatment system as with a high separation capability there is a possibility of developing systems that can recover valuable pharmaceutical components from POME and also recovering high quality water by application of membrane technology to POME treatment systems. Initial lab work and the current treatment applications have led to the selection of centrifugation as the membrane pre-treatment method. The aqueous phase from this process shows decrease in the range of between 60% to 80% of COD, turbidity, color, and suspended solids. This will be the fed to the hollow fiber membrane modules. The modules were of 0.2 Αμιη, 500K, 100K, and 30K MWCOs. The tested system have an overall removal efficiency of 89.9% for COD, 92.9% for colour, 99.4% for suspended solids and 97.9% for turbidity. [Source: Treatment of Pakm Oil Mill Effluent (POME) using Membrane Technology, Regional Symposium on Membrane Science and Technology 2004] Jiuwu Hi-Tech offers solution for POME treatment with an integrated ceramic membrane technology which is which is a green, friendly environment, economic efficiency and has the benefits such as no discharge of wastewater, low capital investment, low operation cost, oil is concentrated and water is recycled. After integrated process filtration, concentrate including surplus sludge from anaerobic and centrifuge is used as fertilizer for cattle farm and purified water can be used for recycling or the boiler feed water due to salts and organic compounds are removed.

[Source: https://www.jiuwumembrane.com/application/palm-oil-wastewate r.html ]

Publication entitled “Sustainability of Palm Oil Industries: An Innovative Treatment via Membrane Technology” [Source: Journal of Applied Sciences, Volume 9 (17): 3074-3079, 2009] describes POME treatment using membrane technology whereby the POME samples used in this research were obtained from a nearby palm oil mill. The raw POME (70°C) was cooled to room temperature (25°C) before subjected to the series of treatments which included the coagulation-flocculation process and activated carbon and membrane separation process (ultrafiltration and reverse osmosis). The pre-treatment processes were successful in reducing almost 99.9% of suspended solids content, 95.0% of oil and grease, 86.3% of BOD and 85.0% of COD in POME before proceeding to the membrane treatment (Ahmad et al, 2005). This is the mitigation approach to reduce membrane fouling. This prior art does not specifically describe a process for treating POME using electro-oxidation process in combination with other processes such as cooling process, coagulation, flocculation, dewatering, membrane separation, mixing POME with electrolytes, filtration or in any combination thereof without the need for aerobic treatment or without the need for aerobic and anaerobic treatments.

Publication entitled “Treatment of Palm Oil Mill Effluent (POME) by Coagulation- Flocculation using different Natural and Chemical Coagulants: A Review” [Source: IOSR Journal of Mechanical and Civil Engineering, Volume 13, Issue 6, Nov-Dec 2016] describes about coagulation-flocculation which is a chemical water treatment technique typically applied prior to sedimentation and filtration to enhance the ability of a treatment process to remove particles. Coagulation-flocculation processes are essential parts of water treatment and the clarification of water using coagulants have been practiced since ancient times. Coagulation is a process used to neutralise charges and form a gelatinous mass to trap or bridge particles thus forming a mass large enough to settle or be trapped in the filter. Flocculation is gentle stirring or agitation to encourage the particles thus formed to agglomerate into masses large enough to settle or be filtered from solution. Pre- treatment of POME using coagulation and flocculation processes has become an important feature to reduce organic load prior to subsequent treatment processes. Numerous researches have reported the success recoded in the treatment of oil mill effluents using coagulation, filtration and settling procedure. Study on POME treatment such as using a series of process such as coagulation, sedimentation, solvent extraction, membrane filtration and adsorption was also found to be successful. This prior art does not specifically describe a process for treating POME using electro-oxiddation process in combination with other processes such as cooling process, coagulation, flocculation, dewatering, membrane separation, mixing POME with electrolytes, filtration or in any combination thereof without the need for aerobic treatment or without the need for aerobic and anaerobic treatments.

Publication entitled “Treatment of Aerobic Treated Palm Oil Mill Effluent (AT-POME) by using Ti02 Photocatalytic Process" [Source: UTM Jurnal Teknologi EISSN 2180-3722] states that despite the reduction of BOD through aerobic or anaerobic biodegradation, the effluent of the treated wastewater (AT-POME) remains dark owing to the degradation of lignocellulosic from the raw POME. In this study, photocatalyst, Ti02 was used to degrade the colour pigment that presence in the AT-POME. Besides, different loadings of Ti02 were used to investigate the effect of catalyst loading towards the photodegradation efficiency. The results showed that 10 wt% of Ti02 can remove more than 70% of the colour pigment in AT-POME. However, the colour reduction only increased slightly when the loading increased from 5 wt% to 10 wt%. This phenomenon occurred due to the agglomeration of nanoparticles in the suspension and the excessive of photocatalyst in the suspension that have prevented the penetration of UV irradiation and consequently slowed down the photo-degradation. This prior art does not specifically describe a process for treating POME using electro-oxidation process in combination with other processes such as cooling process, coagulation, flocculation, dewatering, membrane separation, mixing POME with electrolytes, filtration or in any combination thereof without the need for aerobic treatment or without the need for aerobic and anaerobic treatments.

Publication entitled “Electrooxidation-Ozonation: A Synergistic Sustainable Wastewater Treatment Process” [Source: IntechOpen, May 2017] states that electrooxidation- ozonation is an efficient process for the treatment of different kinds of wastewater, since there is always a large reduction in COD, colour, and turbidity, conductivity and BOD. The coupled process always has a superior performance compared with the application of separated processes. It is also noteworthy to mention that the coupled process is green, as it does not produce residual sludge. This coupled process has the potential to be used in wastewater in which other processes do not work well, including those with recalcitrant pollutants. This prior art does not specifically describe a process for treating POME using electro-oxidation process in combination with other processes such as cooling process, coagulation, flocculation, dewatering, membrane separation, mixing POME with electrolytes, filtration or in any combination thereof without the need for aerobic treatment or without the need for aerobic and anaerobic treatments.

Publication entitled “Electrochemical Oxidation Treatment of Wastewater Using Activated Carbon Electrode” [Source: International Journal of Electrochemical Science, 13 (2018) 1096-1104] presents a study of the synergic effects of electro-sorption and electrochemical oxidation in the simultaneous removal of substances. It has been widely accepted that wastewater contains low concentrations of organic pollutants and several inorganic salts after being biologically treated. The use of electrochemical oxidation techniques in wastewater treatment has been of great interest in recent years. As an excellent and eco-friendly technique for the removal of persistent organic contaminants, electrochemical advanced oxidation processes are ordinarily used with electrons as reagents. This prior art does not specifically describe a process for treating POME using electro-oxidation process in combination with other processes such as cooling process, coagulation, flocculation, dewatering, membrane separation, mixing POME with electroly tes, filtration or in any combination thereof without the need for aerobic treatment or without the need for aerobic and anaerobic treatments. Publication entitled “Electrochemical advanced oxidation processes: today and tomorrow. A review” [Source: Environmental Science and Pollution Research - July 2014, Volume 21, Issue 14, pp 8336-8367] states that a new advanced oxidation processes based on the electrochemical technology, the so-called electrochemical advanced oxidation processes (EAOPs), have been developed for the prevention and remediation of environmental pollution, especially focusing on water streams. These methods are based on the electrochemical generation of a very powerful oxidizing agent, such as the hydroxyl radical (· OH) in solution, which is then able to destroy organics up to their mineralization. EAOPs include heterogeneous processes like anodic oxidation and photoelectrocatalysis methods, in which · OH are generated at the anode surface either electrochemically or photochemically, and homogeneous processes like electro-Fenton, photoelectro-Fenton, and sonoelectrolysis, in which ^. OH are produced in the bulk solution. This prior art does not specifically describe a process for treating POME using electro-oxidation process in combination with other processes such as cooling process, coagulation, flocculation, dewatering, membrane separation, mixing POME with electrolytes, filtration or in any combination thereof without the need for aerobic treatment or without the need for aerobic and anaerobic treatments.

PCT Publication W02011000079A1 describes a wastewater treatment apparatus comprising an electro-coagulation unit to remove a first portion of contaminants from said wastewater comprising at least one inlet to receive said wastewater and at least one anode and at least one cathode, said anode and said cathode being connected to an electric source; said wastewater comprising graywater and/or blackwater, an electro-oxidation unit to oxidize a second portion of contaminants in said wastewater comprising at least one inlet to receive said wastewater from said electro- coagulation unit, at least one boron- doped diamond coated anode configured to create hydroxyl radicals near the anode surface and, at least one cathode wherein oxidants are electrochemically generated, at least one outlet to evacuate said wastewater, and an oxidant removal unit comprising electrodes, that have the effect of liberating iron ions, when current is applied thereto, for reacting residual oxidants with said iron ions to remove oxidants from said wastewater comprising at least one inlet to receive said wastewater from said electro-oxidation unit, a vessel to contain said wastewater during an oxidant removal process and at least one outlet to discharge treated wastewater from said apparatus. This prior art does not specifically describe a process for treating POME using electro-oxidation process in combination with other processes such as cooling process, coagulation, flocculation, dewatering, membrane separation, mixing POME with electrolytes, filtration or in any combination thereof without the need for aerobic treatment or without the need for aerobic and anaerobic treatments.

US Patent Application US20180179097A1 describes about a method comprising generating a first water product and a sludge of contaminants from water to be treated using an advanced electronic-oxidation process, wherein the advanced electronic- oxidation process comprises an electronic treatment comprising a combination of electrocoagulation, electro-flocculation, electro-chlorinator, and electro- dialysis operated in synchronization with ozone, separating the sludge of contaminants from the first water product using a filtration process, filtering the first water product to produce a second water product and a concentrated water by-product, wherein the filtering comprises a first sub-stage to remove particles greater than 0.02 pm to about 0.05 pm followed by a second sub-stage comprising a reverse osmosis process or a nano-filtration process; and exposing the second water product to an ultraviolet light treatment or ozonation process to generate clean water. This prior art does not specifically describe a process for treating POME using electro-oxidation process in combination with other processes such as cooling process, coagulation, flocculation, dewatering, membrane separation, mixing POME with electrolytes, filtration or in any combination thereof without the need for aerobic treatment or without the need for aerobic and anaerobic treatments. All prior arts as listed and referred to above do not specifically describe a process for treating POME specifically using electro-oxidation process in combination with other processes such as cooling process, coagulation, flocculation, dewatering, membrane separation, mixing POME with electrolytes, filtration (in any combination thereof), without the need for aerobic wastewater treatment or without the need for both aerobic and anaerobic treatments. Hence, there remains a need in the art to provide a system to address the above problems or to at least provide an alternative with regards to POME treatment, specifically an improved process for treating POME using electro-oxidation process in combination with other processes such as cooling process, coagulation, flocculation, dewatering, membrane separation, mixing POME with electrolytes, filtration (in any combination thereof), without the need for aerobic treatment or without the need for both aerobic and anaerobic treatments.

SUMMARY OF THE INVENTION The present invention provides a process for treating palm oil mill effluent (POME), the process including the steps of cooling the POME in a cooling pond from a temperature range of between 60° C to 90°C to a temperature range of between 20°C to 60°C to produce cooled POME, flocculating suspended solids using at least one polymer or flocculating and coagulating suspended solids using at least one polymer and coagulants as contained in the cooled POME to produce flocculated suspended solids or flocculated and coagulated suspended solids in the cooled POME, dewatering the flocculated suspended solids as contained in the cooled POME to remove the flocculated suspended solids in the cooled POME using a belt press, filter belt, screw disc, multi disc screw, a decanter or any combinations thereof to produce a dewatered POME, clarifying the dewatered POME to remove sludge from the dewatered POME, removing the coagulated suspended solids from the dewatered POME using a gravity settlement means, a filtration means or a combination of both to produce a partially treated POME, mixing the partially treated POME with at least one electrolyte to produce ionised partially treated POME, delivering the ionised partially treated POME to an electro-oxidation cell comprising at least one electrode which is positively charged (anode), at least one electrode which is negatively charged (cathode) to produce a treated POME or an active oxidizing agent and removing precipitate and/or suspended solids from the treated POME using a filtration means such as a bag filtration, a membrane filtration or a combination of both to produce a fully treated POME. The present invention also provides a process for treating palm oil mill effluent (POME), the process including the steps of passing the POME through at least one membrane module repeatedly in a temperature range of between 50°C to 90°C to separate oil as contained in the POME to produce a partially treated POME containing <50 mg/L oil and grease and suspended solids <50 mg/L, cooling the partially treated POME in a cooling pond from a temperature range of between 60° C to 90°C to a temperature range of between 20°C to 60°C to produce a partially treated cooled POME, mixing the partially treated cooled POME with at least one electrolyte to produce ionised partially treated POME, delivering the ionised partially treated POME to an electro-oxidation cell comprising at least one electrode which is positively charged (anode), at least one electrode which is negatively charged (cathode) to produce a treated POME or an active oxidizing agent and removing precipitate and/or suspended solids from the treated POME using a filtration means such as a bag filtration, a membrane filtration or a combination of both to produce a fully treated POME. The present invention also provides a process for treating palm oil mill effluent (POME), the process including the steps of cooling the POME in a cooling pond from a temperature range of between 60° C to 90°C to a temperature range of between 20°C to 60°C to produce cooled POME, treating the cooled POME anaerobically (in an anaerobic pond to produce pre-treated POME, flocculating suspended solids contained in the pre-treated POME using at least one polymer to produce flocculated suspended solids in the pre-treated POME, dewatering the flocculated suspended solids as contained in the pre-treated POME to remove the flocculated suspended solids in the pre-treated POME using a belt press, filter belt, screw disc, multi disc screw, a decanter or any combinations thereof to produce a dewatered pre-treated POME, coagulating the dewatered pre-treated POME using inorganic and/or organic coagulants to produce coagulated suspended solids, removing the coagulated suspended solids from the dewatered pre-treated POME using a gravity settlement means, a filtration means or a combination of both to produce a partially treated POME, delivering the partially treated POME to an electro-oxidation cell comprising at least one electrode which is positively charged (anode), at least one electrode which is negatively charged (cathode) and at least one electrolyte to create an active oxidizing agent or to produce a treated POME and removing precipitate and/or suspended solids from the treated POME using a filtration means such as a bag filtration, a membrane filtration or a combination of both to produce a fully treated POME.

The present invention further provides a process for treating palm oil mill effluent (POME), the process including the steps of cooling the POME in a cooling pond from a temperature range of between 60° C to 90° C to a temperature range of between 20° C to 60° C to produce cooled POME, treating the cooled POME anaerobically in an anaerobic pond to produce pre-treated POME, flocculating suspended solids contained in the pre- treated POME using at least one polymer to produce flocculated suspended solids in the pre-treated POME, dewatering the flocculated suspended solids as contained in the pre- treated POME to remove the flocculated suspended solids in the pre-treated POME using a belt press, filter belt, screw disc, multi disc screw, a decanter or any combinations thereof to produce a dewatered pre-treated POME, adjusting the pH of the dewatered pre- treated POME using sodium hydroxide, hydrochloric acid, sulphuric acid, sodium chloride or any combination thereof, removing suspended solids from the dewatered pre-treated POME using a gravity settlement means, a filtration means or a combination of both to produce a partially treated POME, delivering the partially treated POME to an electro- oxidation cell comprising at least one electrode which is positively charged (anode), at least one electrode which is negatively charged (cathode) and at least one electrolyte to create an active oxidizing agent or to produce a treated POME and removing precipitate and/or suspended solids from the treated POME using a filtration means such as a bag filtration, a membrane filtration or a combination of both to produce a fully treated POME.

The present invention further provides a process for treating palm oil mill effluent (POME), the process including the steps of cooling the POME in a cooling pond from a temperature range of between 60°C to 90°to a temperature range of between 20°C to 60°C to produce cooled POME, treating the cooled POME anaerobically in an anaerobic pond to produce pre-treated POME, flocculating suspended solids contained in the pre-treated POME using at least one polymer to produce flocculated suspended solids in the pre- treated POME, dewatering the flocculated suspended solids as contained in the p re- treated POME to remove the flocculated suspended solids in the pre-treated POME using a belt press, filter belt, screw disc, multi disc screw, a decanter or any combinations thereof to produce a dewatered pre-treated POME, delivering the dewatered pre-treated POME to an electro-oxidation cell comprising at least one electrode which is positively charged (anode), at least one electrode which is negatively charged (cathode) and at least one electrolyte to create an active oxidizing agent and to produce a partially treated POME and removing precipitate and/or suspended solids from the partially treated POME using a filtration means such as a bag filtration, a membrane filtration or a combination of both to produce a treated POME.

BRIEF DESCRIPTION OF THE DRAWINGS

Above recited features of the present invention may have been referred by embodiments, some of which are illustrated in the appended drawings. The appended drawings illustrate only typical embodiments of this invention and are therefore not considered limiting of its scope as the invention may perform effectively to other equally effective embodiments.

These and other features, benefits and advantages of the present invention will become apparent by reference to the following figures: -

Figure 1 illustrates the conventional means for treatment of palm oil mill effluent (POME).

Figure 2 illustrates the process for treating POME which includes the steps of cooling the POME, flocculating suspended solids, dewatering flocculated suspended solids, clarifying dewatered POME, removing coagulated suspended solids, mixing partially treated POME with electrolytes, delivering partially treated POME to electro-oxidation cell and removing precipitate and/or suspended solids from treated POME.

Figure 3 illustrates the process for treating POME which includes the steps of cooling the POME, flocculating suspended solids, dewatering flocculated suspended solids, clarifying dewatered POME, removing coagulated suspended solids, mixing partially treated POME with electrolytes, delivering partially treated POME to electro-oxidation cell, removing precipitate and/or suspended solids from treated POME, followed by a pH adjustment step of the fully-treated POME and final step of removing precipitate and/or suspended solids from the fully-treated POME.

Figure 4 illustrates the process for treating POME which includes the steps of passing POME through at least one membrane module, cooEng of the POME, mixing partially treated POME with electrolytes, deEvering partially treated POME to electro-oxidation cell and removing precipitate and/or suspended solids from treated POME.

Figure 5 illustrates the process for treating POME which includes the steps of passing POME through at least one membrane module, cooling of the POME, mixing partially treated POME with electrolytes, delivering partially treated POME to electro-oxidation cell, removing precipitate and/or suspended solids from treated POME followed by a pH adjustment step of the fully-treated POME and final step of removing precipitate and/or suspended solids from the fully-treated POME.

Figure 6 illustrates the process for treating POME which includes the steps of cooEng the POME, treating POME anaerobicaUy, flocculating suspended solids, dewatering flocculated suspended solids, coagulating POME (with or without a pH adjustment step), removing coagulated suspended solids, deEvering the POME to the electro-oxidation ceU and removing precipitate / suspended solids to produce fuU treated POME.

Figure 7 illustrates the process for treating POME which includes the steps of cooling the POME, treating POME anaerobically, flocculating suspended solids, dewatering flocculated suspended solids, adjusting pH of POME, filtration to remove solids, deEvering the POME to the electro-oxidation cell and removing precipitate / suspended solids to produce full treated POME.

Figure 8 iUustrates the process for treating POME which includes the steps of cooling the POME, anaerobically treating the POME, flocculating suspended solids, dewatering the flocculated suspended solids, delivering the dewatered POME to an electro-oxidation cell and removing precipitate / suspended solids to produce full treated POME.

Figure 9 Ulustrates the process for treating POME which includes the steps of cooEng the POME, treating POME anaerobically, flocculating suspended solids, dewatering flocculated suspended solids, deEvering POME to the electro-oxidation ceU, removing precipitate / suspended solids, coagulating flocculated suspended solids and removing coagulated suspended solids to produce full treated POME.

Figure 10 illustrates the indirect oxidation method of the electro-oxidation process.

Figure 11 illustrates the direct oxidation method of the electro-oxidation process.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE

PRESENT INVENTION

While the present invention is described herein by way of example using illustrative drawings and embodiments, it should be understood that the detailed description are not intended to limit the invention to embodiments of drawing or drawings described and are not intended to limit the invention to the particular form disclosed but in contrary the invention is to cover all modifications, equivalents and alternatives falling within the scope of the present invention.

The present invention is described herein by various embodiments with reference to the accompanying drawing wherein reference numerals used in the accompanying drawing correspond to the features through the description. However, the present invention may be embodied in many different forms and should not be construed as limited to embodiments set forth herein. Therefore, embodiments are provided so that this disclosure would be thorough and complete and will fully convey the scope of invention to those skilled in the art. Numeric values and ranges and materials as provided in the detailed description are to be treated as examples only and are not intended to limit the scope of the claims of the present invention.

Terminology and phraseology used herein is solely used for descriptive purposes and is not intended as limiting in scope. The words such as “including”, “comprising”, “having”, “containing” or “involving” and other variations is intended to be broad and cover the subject matter as described including equivalents and additional subject matter not recited such as other components or steps.

Background. Palm oil mill effluent (POME) when released into rivers and/or lakes without treatment causes water pollution. POME is largely generated by the sterilisation process of the oil palm fresh fruit bunches (FFB) in the milling process, also via clarification process of the palm oil and effluent from hydro-cyclone operations. Normally, for a 60 MT/hr the average POME production is about 21,000 MT/month for a 20-hour operation per day for a period of 25 days per month. Ratio of water to oil palm FFB processed varies from as low as 0.5 MT to 1.5 MT for 1 MT of FFB processed.

Characteristics of POME are as follows: [Source: Palm Oil Mill Effluent as an Environmental Pollutant, Chapter 2, IntechOpen]

As mentioned above, treatment of POME in Malaysia has been via a series of treatment consisting of anaerobic, facultative and aerobic pond systems. More than 85% of mills in Malaysia uses ponding system in treating POME and anaerobic digestion is currently used as the primary method of treating POME. This is due to the fact that anaerobic digestion is suited to treat effluent containing high concentration of organic carbon, as POME in general has high biochemical oxygen demand (BOD) and high chemical oxygen demand (COD). Most of the palm oil mills use open ponding system for POME treatment due to the low costs involved and operational simplicity, which generally consists of four types of ponds namely the fat pit, cooling pond, anaerobic pond and aerobic pond. Although ponding systems are largely used by the industry due to economic perspective, however, it is land and time intensive (i.e. requires long retention times and large treatment areas) and also releases large amount of methane gas into the atmosphere.

The oil palm mills essentially generate POME which can harm the environment if not properly treated before being discharged into bodies of water. Hence, the purpose of POME treatment is to reduce the biological strength of the POME to allowable standards which will not be harmful to the environment, when discharged. There are known methods to treat POME, such as:-

[ Source : A Review of Palm Oil Mill Effluent (POME) Water Treatment, Global Journal of Environmental Research, 1 (2): 54-62, 2007]

• Tank digestion and facultative ponds whereby the wastewater is pumped to a closed tank and kept for a certain number of days, then mixed via horizontal stirrers, digested liquid proceeds to a holding pond before being disposed on land.

• Tank digestion and mechanical aeration consists of cooling / acidification ponds, anaerobic digestion tank and an aeration pond. Wastewater goes through cooling tower, acidification pond and mixed with liquid from anaerobic digester before fed to digester, then discharged to an aeration pond before being discharged.

• Decanter and facultative ponds is where decanters are used to separate oil after pressing into liquid and solid phases. Water from clarification station is recycled, solid disposed-off on land, effluent consisting of steriliser condensate and waste is then treated in a series of ponds.

• Anaerobic and facultative ponds consist of a series of ponds such as acidification buffering pond, then wastewater is treated in an anaerobic pond with HRT of about 30 to 80 days depending on the mills, then treated in a series of facultative ponds before being discharged.

• Antra system, which is a combination of mechanical chemical process and ponds, whereby, the water containing dissolved solids and suspended solids are treated with coagulants and flocculants to remove as much solids as possible before being sent to the anaerobic digester.

Conventional means to process POME is illustrated as per Figure 1, whereby the POME first goes through a cooling process to reduce temperature of POME to about 45°C in preparation to proceed to the anaerobic process. After anaerobic process, POME will proceed to the aerobic process. All in all, the conventional process requires very high hydraulic retention time (HRT), which is more than 100 days and requires large treatment areas. HRT for anaerobic process is around 40 days and HRT for aerobic process is around 60 days. General methods in a POME treatment include the following such as sedimentation by coagulation and flocculation, membrane filtration process, adsorption and electrocoagulation. POME consists of large amount of biodegradable organic matter which requires a series of biological treatment via anaerobic, aerobic and facultative processes in order to degrade the organic matter of POME before being discharged into bodies of water, such as rivers, lakes and/or ponds. These biological processes depend greatly on consortium of microorganisms to degrade the organic matters to produce by-products such as methane, carbon dioxide and water.

Definitions

“Biochemical oxygen demand (BOD)” for this present invention refers to amount of oxygen that bacteria will consume while decomposing the organic matters in POME under aerobic conditions. 100 ppm is the current limit for standard of discharge for BOD in POME in Malaysia. However, there are some mills which have been imposed of a more stringent standard of discharge for BOD in POME at about 20 ppm. “Chemical oxygen demand (COD)" for this present invention refers to the total quantity of oxygen required to oxidize all organic materials in POME into carbon dioxide and water. In general COD value is greater than a BOD value.

“Aerobic process” or “aerobic digestion” or “aerobic treatment” refers to the degradation of organic materials in POME in the presence of oxygen. This process utilises aerators to provide oxygen during the process, hence, requires high energy.

“Anaerobic digestion” or “anaerobic process” or “anaerobic treatment” refers to the degradation of organic materials by anaerobic bacteria in POME in the absence of oxygen. Examples of resulting products of anaerobic digestion are methane and carbon dioxide. The process generally begins with bacterial hydrolysis to break down insoluble organic polymers into soluble derivatives and then acidogenic bacteria proceeds to convert soluble derivatives into carbon dioxide, hydrogen, ammonia and volatile fatty acids. Methanogenic bacteria will then proceed to convert the volatile fatty acids to methane and carbon dioxide. “Volatile fatty acids (VFA) content” for the purposes of this present invention are mainly composed of butyric acid, acetic acid, propionic acid, lactic acid and ethanol. VFA content is used to determine whether anaerobic digestion has been completed or not. Anaerobic digestion is considered as complete when then VFA content is in the range of between 50 ppm to 300 ppm, preferably between 50 ppm to 150 ppm. It is not preferred for the VFA content to be below 100 ppm as this will cause starvation to the methanogenic bacteria and hence the anaerobic digestion process will be ineffective, as starvation causes the methanogenic bacteria to consume other methanogenic bacteria in the pond hence reducing the amount of bacteria required for an effective anaerobic digestion process.

“Cooling pond” for the purposes of this present invention means a man-made body of water for cooling the POME discharged from the palm oil miffing process to a range preferably between 35°C to 45°C. This range temperature is preferable as mesophilic bacteria are mainly used in the anaerobic ponding systems, whereby, these bacteria are most active in moderate temperatures ranging between 15°C to 45°C.

“Hydraulic retention time (HRT)” for the purposes of this present invention means the holding time of POME for treatment of POME in an anaerobic pond or holding time for treatment of POME in an aerobic pond. HRT for anaerobic treatment is in the range of between 3 to 80 days, around 40 to 60 days, generally 40 days for anaerobic ponds and around 20 days for anaerobic digesters. HRT for aerobic treatment in aerobic ponds is around 60 days. Generally, HRT is calculated with the formula: pond volume (m ³ ) / flow rate (m ³ /day). “Ammoniacal Nitrogen (AN) value” for this present invention refers to the measure of amount of ammonia (which is a toxic pollutant) in POME. AN value for this present invention in in the range of between 0 mg/L to 20 mg/L, preferably 0 mg/L to 10 mg/L.

“Suspended solids” for the purposes of this present invention means the measure of the dissolved content of both inorganic and organic materials in POME in suspended form, preferably to be below 200 ppm in the final treated effluent discharge (treated POME).

“Dewatering” for this present invention means to remove the flocculated suspended solids from anaerobically treated POME via a belt press, filter belt, screw disc, multi disc screw, a decanter or any combination thereof, preferably using filter belt or screw disc. Normal anaerobic conditions applies for the dewatering process, however, there is no retention time for dewatering process as it is a continuous process.

“Gravity settlement” for this present invention means separating the solid phase (i.e. suspended solids and/or solids) and liquid phase, whereby suspended solids and/or solids present in POME has a specific gravity greater than that of water hence will tend to settle down due to gravity force (i.e. gravity settling). Purpose is to remove coagulated impurities after the coagulation step such as metal oxides which precipitates out from the system and/or inorganic / organic materials. Metal impurities as contained in the POME consists of such as zinc, copper, nickel, ferum and lead [Source: International Journal of Environmental Quality, Vol 23(2017)]. "Metal oxides” typically contain an anion of oxygen in the oxidation state of -2 and refers to such as ferum oxide, zinc oxide, nickel oxide and others for the purpose of the present invention.

“Filtration” for this present invention means to remove precipitate such as ferum oxide, nickel oxide and zinc oxide from the treated POME via bag filtration means, membrane filtration means or any combination thereof with pore size in the range of between 1 micron to 100 microns, preferably 1 micron to 50 microns and most preferably 1 micron to 10 microns. Filtration for this present invention could also mean removal of coagulated suspended solids from the POME (i.e. dewatered POME).

“Polymer” for this present invention means a type of compound used in the flocculation process to enhance the flocculation process. Polymers can be natural or synthetic compounds and are available in various forms including solutions, powders or beads, oil or water-based emulsions. Any forms may be used for this present invention depending on preference, availability and cost. Types of polymer that can be used for this present invention are polyacrylamide, polypropylene, polyamines, polytannin or any combination thereof, preferably polyacrylamide. Polyacrylamide is preferred for this present invention as based on trials done by the inventors for this present invention and also other related projects conducted by the inventors pertaining to wastewater treatment, polyacrylamide is found to work best and provides good and acceptable results with respect to the flocculation process.

“Coagulation” is a process to form viscous or gelatinous mass to bridge particles together to form mass large enough to be trapped in a filter. Finely dispersed solids suspended in the wastewaters are stabilised by negative electric charges on their surfaces which prevents them from colliding to form larger masses (i.e. coagulate), hence, coagulation process is required. Chemicals (known as flocculants) are used to encourage the particles already formed to form larger masses / particles which can be filtered away more easily from the wastewaters. Rapid mixing (in a range of between 100 rpm to 200 rpm) is required for the coagulation process. Rapid mixing is required to ensure all solids are coagulated properly. If too slow (< 100 rpm) or too fast (> 200 rpm), coagulation will not happen effectively. Coagulants (positive metal ion) used in a coagulation process would firstly neutralise electrical charges on colloidal particles causing the particles not to repel from each other, hence bringing them together into larger and heavier masses, known as coagulate. If the mixing is too slow, chances of the coagulants to be in contact with desired particles / substrate is low and if the mixing is too fast, the coagulates might break-up. Coagulants that can be used for the present invention are iron based coagulants, aluminium based coagulants or any combination thereof, such as ferum chloride, ferric chloride, ferrous sulphate, poly aluminium chloride (PAC) and aluminium sulphate.

“pH adjustments” can be done using chemicals such as sodium hydroxide, hydrochloric acid, sulphuric acid, sodium chloride and others. pH values affect the surface charges (electrons) and forms coagulants and allows impurities to be removed, hence, controlling the level of pH which would significantly improve the coagulation process. Therefore, the coagulation step can be improved to achieve its maximum efficiency not just by optimising the dosage of coagulants but also by adjusting and optimising the pH value to maximise the removal of impurities from the wastewater. The pH adjustments can be done without a coagulation step or with a coagulation step (before and/or after the coagulation step). This is an additional step to provide an optimum pH level for coagulation performance depending on the chemicals used in the coagulation step. pH adjustments done after the coagulation step is basically to provide an optimum condition for electro-oxidation process as pH < 7 will produce hypochlorous ion, whereas pH > 7 will produce hypochlorite. This step can be determined by the respective mill based on preference and cost / expenditure. For the purposes of the present invention, coagulation can be achieved with or without an additional step of adjustment to the pH value of the POME (which would automatically adjust the surface charges (electrons) of the POME). Coagulation without a pH adjustment step is acceptable as the pH operating conditions for the coagulation step are in between pH 6 to pH 8 (falls within the operating pH range for coagulants).

“Flocculation” is a process to form a bigger coagulate i.e. floe by using polymer. Polymer having high molecular weight and branching structure will trap the coagulate thus forming bigger particulate. Slow mixing (< 50 rpm) is preferred for the flocculation process as opposed to the coagulation process. Slow mixing is crucial to ensure that flocculation happens effectively / all solids are flocculated properly. “Electro-oxidation” process for this present invention refers to a technique used for wastewater treatment with a general layout of an electro-oxidation cell consisting of two electrodes (anode and cathode) and with presence of an electrolyte and power source, oxidizing agents are form which would then interact with the organic matter of POME and degrade them, while also producing by-products such as carbon dioxide and water. One of the key benefit is that less sludge / solids is produced using POME treatment using electro-oxidation as compared to conventional means, as the organic matter of POME is converted into carbon dioxide and only inorganic matter is converted into solids (i.e. sludge). Apart from that, there are no use of bacteria involved, hence no solid accumulation due to dead bacteria will be found using this process as opposed to aerobic process which produces high solid due to the microbe propagation rate. The electro- oxidation cell which consists of two electrodes (anode and cathode) exist as anode and cathode plates or anode and cathode plates together with a contactor in between the anode and cathode plates for this present invention. The contactor used can be from materials such as activated carbon, zeolites, ion exchange resin or any preferred material which can enable / allow transfer of surface charges (electrons) of the POME. The anode and cathode plates as mentioned above can be used with or without a contactor in between the plates. Both works efficiently for the present invention. Usage of a contactor would depend on type of effluent / content of POME and preference / cost. The contactor provides an additional benefit whereby less reaction time is required (when a contactor is used) for the same surface area of the plate, hence, resulting in lower capital expenditure.

“Oxidizing agent” for this present invention generally refers to an oxidant such as chlorine, oxygen and/or hydroxyl ion (OH-) which brings about oxidation, readily transfers oxygen atoms or gains electrons in a chemical reaction. For the purposes of this present invention, the oxidation process happens by introducing the hydroxyl ion (OH ^" ) to POME to produce bio-products such as carbon dioxide and water.

“Retention time” for this present invention means the reaction time of the in the electro- oxidation cell to produce treated POME and/or an active oxidizing agent such as is a chlorine, oxygen and/or hydroxyl ion (OH ^" ), preferably chlorine in a concentration of between 0 to 10%. The reaction time produce the treated POME is in a range of between 1 minute to 600 minutes (10 hours), preferably 30 minutes to 300 minutes (5 hours) and most preferably 30 minutes to 180 minutes (3 hours). The reaction time to produce the active oxidizing agent is in a range of between 5 minutes to 1,200 minutes (20 hours), preferably 30 minutes to 900 minutes (15 hours) and most preferably 30 minutes to 600 minutes (10 hours).

“Membrane separation” for this present invention means the use of membrane to separate POME into two streams i.e. retentate (consisting of solids, oil and water) and permeate (water and dissolved solids, containing negligible solid and oil). The retentate is that part of the POME that does not pass through the membrane, while the permeate is that part of the POME that passes through the membrane. The concentration of the oil in the retentate is higher than what is contained in POME before going through the membrane module, hence would allow additional oil to be recovered (increase in oil recovery). BOD and COD readings of the permeate reduces drastically as solids are captured as retentate via the membrane separation means which would translate into shorter time for further treatment of the POME till desired discharge (treated POME) quality is achieved. Membrane technology is well suited for the purposes of this present invention. More than 1 membrane module can be used for this present invention (which would be installed in series or in parallel, preferably in series for this present invention) as the number of membrane modules depends on the capacity of the membrane system which is installed in the mills. Hence, more membrane modules would be required for a bigger size system.

Objectives of the Present Invention An object of the present invention is to produce a fully treated POME for discharge into bodies of water which is colourless, has a BOD value in a range of between 0 mg/L to 20 mg/L, preferably in the range of between 0 mg/L to 10 mg/L, most preferably in a range of between 0 mg/L to 5 mg/L and an ammoniacal nitrogen (AN) value in a range of between 0 mg/L to 20 mg/L preferably in the range of between 0 mg/L to 10 mg/L.

An object of the present invention is also to introduce POME treatment via electro- oxidation process as it is easy to use and is a robust technology with only a simple electrochemical cell required with electrons as the main reagent, minimal addition of chemicals required and carried out at atmospheric pressure. Another object of the present invention is to produce chlorine via the electro-oxidation means in a concentration of between 0.1% to 10%, preferably 1% to 8% and most preferably 6% to 8% which can be sold as industrial grade sodium hypochlorite. Sodium hypochlorite is essentially used as an oxidizing reagent with its commercial retail brand being chlorox. Hence, sodium hypochlorite can be produced instead treated wastewater for discharge into bodies of water for commercial use and purposes.

Another object of the present invention is to reduce land area by at least 95% when comparing with conventional means of POME treatment. Essentially, the introduction of this electro-oxidation process in combination with other processes such as cooling process, anaerobic treatment, coagulation, flocculation, dewatering, membrane separation, mixing POME with electrolytes, filtration (in any combination thereof), would replace the current aerobic treatment process, whereby, the proposed combination of process will consume less HRT. In general, HRT for aerobic pond is determined based on the equation: BOD(in) = BOD(out) / (1+kHRT), k=constant], HRT mainly depends on the incoming wastewater to the pond and is determined based on appearance of the wastewater when it turns to light brown and pH of the water is in a range of between 7 to 9. Using the electro-oxidation means, the retention time to create active oxidizing agent is in a range of between 5 minutes to 1,200 minutes (20 hours), preferably 30 minutes to 900 minutes (15 hours) and most preferably between 30 minutes to 600 minutes (10 hours) and the retention time to create treated POME is 1 minute to 600 minutes (1.0 hours), preferably 30 minutes to 300 minutes (5 hours) and most preferably 30 minutes to 180 minutes (3 hours). Hence, total HRT using this process would be around 40 days as compared to 100 days of the conventional POME treatment process

The object of the present invention is also to reduce land area by a 100% when comparing with conventional means of POME treatment. Essentially, the introduction of this electro- oxidation process could also replace the current aerobic and anaerobic treatment processes, whereby, the HRT would be 1 day as compared to 100 days for conventional POME treatment means. Using the electro-oxidation means, the retention time to create active oxidizing agent is in a range of between 5 minutes to 1,200 minutes (20 hours), preferably 30 minutes to 900 minutes (15 hours) and most preferably between 30 minutes to 600 minutes (10 hours) and the retention time to create treated POME is 1 minute to 600 minutes (10 hours), preferably 30 minutes to 300 minutes (5 hours) and most preferably 30 minutes to 180 minutes (3 hours). Apart from that, this is also methane avoidance process whereby no methane gas is released to the environment (i.e. reduce negative impact of release of greenhouse gas into the atmosphere via conventional means).

The object of the present invention is to provide a new series / combination of processes for POME treatment (without aerobic and anaerobic process treatment) which includes cooling of POME in a cooling pond, flocculation / flocculation and coagulation, dewatering of the flocculated suspended solids, clarification to remove sludge, removing the coagulated suspended solids, mixing POME with electrolytes, electro-oxidation process followed by filtration.

The object of the present invention further provides a new series / combination of processes for POME treatment (without aerobic and anaerobic process treatment) which includes cooEng of POME in a cooEng pond, flocculation / flocculation and coagulation, dewatering of the flocculated suspended solids, clarification to remove sludge, removing the coagulated suspended solids, mixing POME with electrolytes, electro-oxidation process followed by filtration, pH adjustment step and a further filtration step.

A further object of the present invention is to provide a new series / combination of processes for POME treatment (without aerobic and anaerobic process treatment) which includes membrane separation, mixing POME with electrolytes, electro-oxidation process followed by filtration.

A further object of the present invention is to provide a new series / combination of processes for POME treatment (without aerobic and anaerobic process treatment) which includes membrane separation, mixing POME with electrolytes, electro-oxidation process followed by filtration, pH adjustment step and a further filtration step.

A further object of the present invention is to provide a new series / combination of processes for POME treatment (without aerobic process treatment) which includes cooEng of POME in a cooEng pond, anaerobic treatment of the POME, flocculation of suspended solids using polymer, dewatering of the flocculated suspended solids, coagulation (with or without the additional step of adjustment to the pH value of the POME, whereby this step would automatically adjust the surface charges of the POME - which can be done before and/or after the coagulation step) of the dewatered pre-treated POME using coagulants, removing the coagulated suspended solids and electro-oxidation process foUowed by filtration. A further object of the present invention is to provide a new series / combination of processes for POME treatment (without aerobic process treatment) which includes cooling of POME in a cooling pond, anaerobic treatment of the POME, flocculation of suspended solids using polymer, dewatering of the flocculated suspended solids, pH adjustment step (without a coagulation step) of the dewatered pre-treated POME using sodium hydroxide, hydrochloric acid, sulphuric acid, sodium chloride or any combination thereof, removal of the suspended solids and electro-oxidation process followed by filtration.

A further object of the present invention is to provide another new series / combination of processes for POME treatment (without aerobic process treatment) which includes cooling of POME in a cooling pond, anaerobic treatment of the POME, flocculation of suspended solids using polymer, dewatering of the flocculated suspended solids, electro-oxidation process, coagulation of the oxidized POME using coagulants and removing the coagulated suspended solids.

A further object of the present invention is to provide a further new series / combination of processes for POME treatment (without aerobic process treatment) which includes cooling of POME in a cooling pond, anaerobic treatment of the POME, flocculation of suspended solids using polymer, dewatering of the flocculated suspended solids and electro-oxidation process, without involving a coagulation process.

Specific Embodiments of the Present Invention

Referring to Figures 2 and 3. the present invention provides a first embodiment as follows:

A process for treating palm oil mill effluent (POME), the process including the steps of: a) cooling the POME (1) in a cooling pond from a temperature range of between 60°C to 90°C to a temperature range of between 20°C to 60°C to produce cooled POME; b) flocculating suspended solids using at least one polymer or flocculating and coagulating suspended solids using at least one polymer and coagulants (2) as contained in the cooled POME to produce flocculated suspended solids or flocculated and coagulated suspended solids in the cooled POME; c) dewatering the flocculated suspended solids (3) as contained in the cooled POME to remove the flocculated suspended solids in the cooled POME using a belt press, filter belt, screw disc, multi disc screw, a decanter or any combinations thereof to produce a dewatered POME; d) clarifying the dewatered POME (4) to remove sludge from the dewatered POME; e) removing the coagulated suspended solids (5) from the dewatered POME using a gravity settlement means, a filtration means or a combination of both to produce a partially treated POME; f) mixing the partially treated POME with at least one electrolyte (6) to produce ionised partially treated POME; g) delivering the ionised partially treated POME to an electro-oxidation cell (7) comprising at least one electrode which is positively charged (anode), at least one electrode which is negatively charged (cathode) to produce a treated POME or an active oxidizing agent; and h) removing precipitate and/or suspended solids from the treated POME (8) using a filtration means such as a bag filtration, a membrane filtration or a combination of both to produce a fully treated POME. pH levels of the said process are as follows: · pH levels of step a) is less than 5.0 (The incoming wastewater is acidic in nature, and usually is at pH levels of less than 5.0).

• pH levels of steps b) to e) is between 4.0 to 7.5, preferably 4.0 to 7.0 and most preferably 4.5 to 7.0. The addition of polymer to the POME would dilute the POME, hence causing increase in the pH levels.

• pH levels of step f) is between 2.0 to 9.0, preferably 2.0 to 7.0 and most preferably 2.0 to 6.0. The pH level at this stage would depend on the type of electrolyte to mix with POME. Addition of the electrolytes would result in the drop of pH level of the POME. • pH levels of steps g) to h) is between 2.0 to 9.0, preferably 5.0 to 9.0 and most preferably 5.0 to 8.0. The range here is wide as there are several ways to approach steps e) and h) as these steps are flexible and depends on preference and cost / expenditure of a particular mill. During the coagulation step (without the additional step of pH adjustment), coagulation is done using coagulants such as ferric chloride which will bring the pH of the wastewater to a pH range of between 5.0 to 6.0. If the coagulation with the pH adjustment step using sodium chloride as an example, the pH level of the wastewater will be maintained in the range of between 5.0 to 6.0. During step g), the pH levels of the wastewater will increase, up to a maximum of 9.0 [this is because electro-oxidation process will consume ions as contained in the POME to produce the oxidizing agent] . If hydrochloric acid is used as another example, pH will drop to about 2 prior to proceeding to step g). Again during step g), the pH levels of the wastewater will increase, up to a maximum of 9.0. Flocculating suspended solids using at least one polymer is sufficient to produce flocculated suspended solids as contained in the cooled POME. However, a flocculating and coagulating suspended solids using at least one polymer and coagulants as contained in the cooled POME to produce flocculated suspended solids or flocculated and coagulated suspended solids in the cooled POME can also be used for the present invention depending on amount of organic matter as contained in the POME. If organic matter in POME is on a higher side or higher than usual, flocculation and coagulation could be needed for this step.

An additional step of adjusting pH of the fully treated POME can be performed after step h) if required using sodium hydroxide, hydrochloric acid, sulphuric acid, sodium chloride or any combination thereof. pH adjustment is required in the event the pH of the treated POME has a pH reading below 5, hence, this pH adjustment is required to adjust pH levels to be between 5.0 to 9.0. Filtration step after that pH adjustment is required to remove any additional impurities left in the treated POME,

Using the electro-oxidation process, the retention time to create active oxidizing agent is in a range of between 5 minutes to 1,200 minutes (20 hours), preferably 30 minutes to 900 minutes (15 hours) and most preferably between 30 minutes to 600 minutes (10 hours) and the retention time to create treated POME is 1 minute to 600 minutes (10 hours), preferably 30 minutes to 300 minutes (5 hours) and most preferably 30 minutes to 180 minutes (3 hours). Hence, total HET using this process would be around 1 day as compared to 100 days of the conventional POME treatment process.

Referring to Figures 4 and 5, the present invention provides a second, embodiment as follows:

A process for treating palm oil mill effluent (POME), the process including the steps of: a) passing the POME through at least one membrane module (11) repeatedly in a temperature range of between 50°C to 90°C to separate oil as contained in the POME to produce a partially treated POME containing <50 mg/L oil and grease and suspended solids <50 mg/L; b) cooling the partially treated POME (12) in a cooling pond from a temperature range of between 60°C to 90°C to a temperature range of between 20°C to 60°C to produce a partially treated cooled POME; c) mixing the partially treated cooled POME with at least one electrolyte (13) to produce ionised partially treated POME; d) delivering the ionised partially treated POME to an electro-oxidation cell (14) comprising at least one electrode which is positively charged (anode), at least one electrode which is negatively charged (cathode) to produce a treated POME or an active oxidizing agent; and e) removing precipitate and/or suspended solids from the treated POME (15) using a filtration means such as a bag filtration, a membrane filtration or a combination of both to produce a fully treated POME. pH levels of the said process are as follows:

• pH levels of steps a) to b) is less than 5.0 (The incoming wastewater is acidic in nature, and usually is at pH levels of less than 5.0). • pH levels of step c) is between 2.0 to 9.0, preferably 2.0 to 7.0 and most preferably 2.0 to 6.0. The pH level at this stage would depend on the type of electrolyte to mix with POME. Addition of the electrolytes would result in the drop of pH level of the POME. · pH levels of steps d) to e) is between 4.0 to 7.5, preferably 4.0 to 7.0 and most preferably

4.5 to 7.0 [this is because electro-oxidation process will consume ions as contained in the POME to produce the oxidizing agent].

An additional step of adjusting pH of the fully treated POME can be performed after step h) if required using sodium hydroxide, hydrochloric acid, sulphuric acid, sodium chloride or any combination thereof. pH adjustment is required in the event the pH of the treated POME has a pH reading below 5, hence, this pH adjustment is required to adjust pH levels to be between 5.0 to 9.0. Filtration step after that pH adjustment is required to remove any additional impurities left in the treated POME,

Using the electro-oxidation process, the retention time to create active oxidizing agent is in a range of between 5 minutes to 1,200 minutes (20 hours), preferably 30 minutes to 900 minutes (15 hours) and most preferably between 30 minutes to 600 minutes (10 hours) and the retention time to create treated POME is 1 minute to 600 minutes (10 hours), preferably 30 minutes to 300 minutes (5 hours) and most preferably 30 minutes to 180 minutes (3 hours). Hence, total HRT using this process would be around 1 day as compared to 100 days of the conventional POME treatment process.

The POME is passed through the membrane in a continuous / repeated manner to produce a partially treated POME containing <50 mg/L oil and grease and suspended solids <50 mg/L. The membrane module functions to separate POME into retentate (consisting of solids, oil and water) and permeate (water and dissolved solids, containing negligible solid and oil). The retentate is that part of the POME that does not pass through the membrane, while the permeate is that part of the POME that passes through the membrane. The concentration of the oil in the retentate is higher than what is contained in POME before going through the membrane module, hence would allow additional oil to be recovered (increase in oil recovery). Content of suspended solids in POME before passing through membrane module is usually between the range of 1% to 4%. Essentially, POME will pass through the series of membrane modules until the desired concentration of oil is achieved in the retentate. For example, if let’s say the oil percentage in the POME prior to passing through the membrane module is 1% and after going through a series of membrane modules, the percentage of oil would increase to >4% (to at least 4 times of the initial oil concentration). Hence, the purpose of the membrane separation process is essentially to increase the concentration of oil in the retentate from a minimum of 0.5% to >2% (i.e. to at least 4 times of the initial concentration).

The membrane module can function continuously or in batch mode, preferably in a continuous mode. 1 or more than 1 membrane module can be used for this present invention (which would be installed in series or in parallel, preferable in series for this present invention) as the number of membrane modules depends on the capacity of the membrane system which is installed in the mills. Hence, more membrane modules would be required for a bigger size system. The pore size of the membrane module is between 0.01 micron to 0.1 micron, preferably 0.05 micron for the purposes of the present invention. Essentially, any suitable material can be used for the membrane module as long as it is able to withstand temperature of between 50°C to 90° C. The membrane module for this present invention can be a ceramic membrane, multi-tubular membrane, ultrafiltration membrane, metal membrane or any combinations thereof, preferably a ceramic membrane as it is found by the inventors to work best under the process conditions required for membrane oil separation.

After the POME passes through the membrane module and a cooling pond, then the partially treated cooled POME is mixed with electrolytes to produce ionised partially treated POME. The mixing can be done in any types of chamber or pipe such as mixing chamber, inline mixer, mixing piper or any combinations thereof. Electrolytes here refers to sodium chloride, sodium sulphate, hydrochloric acid, sulphuric acid or any combinations thereof. The purpose of mixing the electrolytes with the POME is to provide the necessary ions which are required for reaction and conductivity for the electro- oxidation process in the electro-oxidation cell. For this purpose, a pH adjustment step is not required as the mixing with electrolytes provides the POME to be in an acidic condition. The pH of POME after mixing with electrolytes will be as low as 2. The reaction time for mixing the POME with the electrolytes is in a range of between 1 minute to 30 minutes, preferably between 5 minutes to 10 minutes. Referring to Figure 6, the present invention provides a third embodiment as follows: A process for treating palm oil mill effluent (POME), the process including the steps of: a) cooling the POME (18) in a cooling pond from a temperature range of between 60°C to 90°C to a temperature range of between 20°C to 60°C to produce cooled POME; b) treating the cooled POME anaerobically (19) in an anaerobic pond to produce pre- treated POME; c) flocculating suspended solids (20) contained in the pre-treated POME using at least one polymer to produce flocculated suspended solids in the pre-treated POME; d) dewatering the flocculated suspended solids (21) as contained in the pre-treated POME to remove the flocculated suspended solids in the pre-treated POME using a belt press, filter belt, screw disc, multi disc screw, a decanter or any combinations thereof to produce a dewatered pre-treated POME; e) coagulating the dewatered pre-treated POME (22) using inorganic and/or organic coagulants to produce coagulated suspended solids; f) removing the coagulated suspended solids (23) from the dewatered pre-treated POME using a gravity settlement means, a filtration means or a combination of both to produce a partially treated POME; g) delivering the partially treated POME to an electro-oxidation cell (24) comprising at least one electrode which is positively charged (anode), at least one electrode which is negatively charged (cathode) and at least one electrolyte to create an active oxidizing agent or to produce a treated POME; and h) removing precipitate and/or suspended solids from the treated POME (25) using a filtration means such as a bag filtration, a membrane filtration or a combination of both to produce a fully treated POME. pH levels of the said process are as follows:

• pH level of step a) is less than 5.0 [The incoming wastewater is acidic in nature, and usually is at pH levels of less than 5.0. The first phase on the anaerobic digestion process is very rapid whereby the acid bacteria converts the organic components of the POME into simpler molecules (known as VFA) which is later digested to produce methane gas. This process of converting the organic components into simpler molecules depresses the pH levels to higher levels.].

• pH levels of steps b) to d) is between 4.0 to 7.5, preferably 4.0 to 7.0 and most preferably 4.5 to 7.0 as methanogenic bacteria work the most effective in pH levels of between 7.0 to 7.5.

• pH levels of steps e) to h) is between 2.0 to 9.0, preferably between 2.0 and 7.0 and most preferably between 2.0 to 6.0. The range here is wide as there are several ways to approach steps e) and h) as these steps are flexible and depends on preference and cost / expenditure of a particular mill. During the coagulation step (without the additional step of pH adjustment), coagulation is done using coagulants such as ferric chloride which will bring the pH of the wastewater to a pH range of between 5.0 to 6.0. If the coagulation with the pH adjustment step using sodium chloride as an example, the pH level of the wastewater will be maintained in the range of between 5.0 to 6.0. During step g), the pH levels of the wastewater will increase, up to a maximum of 9.0. If hydrochloric acid is used as another example, pH will drop to about 2 prior to proceeding to step g). Again during step g), the pH levels of the wastewater will increase, up to a maximum of 9.0.

The hydraulic retention time (HRT) of step b) is between 3 to 80 days, preferably 40 days. The VFA content of the pre-treated POME of step b) is below 500 ppm, preferably in a range of between 50 ppm to 300 ppm and most preferably in a range of between 100 ppm to 150 ppm. It is not preferred for the VFA content to be below 100 ppm as this is not a conducive environment and will cause starvation to the methanogenic bacteria and hence the anaerobic digestion process will be ineffective.

Using the electro-oxidation process, the retention time to create active oxidizing agent is in a range of between 5 minutes to 1,200 minutes (20 hours), preferably 30 minutes to 900 minutes (15 hours) and most preferably between 30 minutes to 600 minutes (10 hours) and the retention time to create treated POME is 1 minute to 600 minutes (10 hours), preferably 30 minutes to 300 minutes (5 hours) and most preferably 30 minutes to 180 minutes (3 hours). Hence, total HRT using this process would be around 40 days as compared to 100 days of the conventional POME treatment process.

Step e) can be performed without an additional step of adjusting pH of the dewatered pre- treated POME (5) or step e) can be performed with an additional step of adjusting pH of the dewatered pre-treated POME (5). The pH of the dewatered pre-treatment POME can be adjusted using sodium hydroxide, hydrochloric acid, sulphuric acid, sodium chloride or any combination thereof — as further illustrated below.

3A - The present invention provides a first variation of the third embodiment as follows:

A process for treating palm oil mill effluent (POME), the process including the steps of: a) cooling the POME (1) in a cooling pond from a temperature range of between 60°C to 90°C to a temperature range of between 20°C to 60°C to produce cooled POME; b) treating the cooled POME anaerobically (2) in an anaerobic pond to produce pre- treated POME; c) flocculating suspended solids (3) contained in the pre-treated POME using at least one polymer to produce flocculated suspended solids in the pre-treated POME; d) dewatering the flocculated suspended solids (4) as contained in the pre-treated POME to remove the flocculated suspended solids in the pre-treated POME using a belt press, filter belt, screw disc, multi disc screw, a decanter or any combinations thereof to produce a dewatered pre-treated POME; e) adjusting the PH of the dewatered pre-treated POME using sodium hydroxide, hydrochloric acid, sulphuric add, sodium chloride or anv combination thereof, followed bv coagulation using inorganic and/or organic coagulants to produce coagulated suspended solids (5): f) removing the coagulated suspended solids (6) from the dewatered pre-treated POME using a gravity settlement means, a filtration means or a combination of both to produce a partially treated POME; g) delivering the partially treated POME to an electro-oxidation cell (7) comprising at least one electrode which is positively charged (anode), at least one electrode which is negatively charged (cathode) and at least one electrolyte to create an active oxidizing agent and to produce a treated POME; and h) removing precipitate and/or suspended solids from the treated POME (8) using a filtration means such as a bag filtration, a membrane filtration or a combination of both to produce a fully treated POME.

3B - The present invention provides a second variation of the first embodiment as follows:

A process for treating palm oil mill effluent (POME), the process including the steps of: a) cooling the POME (1) in a cooling pond from a temperature range of between 60°C to 90°C to a temperature range of between 20°C to 60°C to produce cooled POME; b) treating the cooled POME anaerobically (2) in an anaerobic pond to produce pre- treated POME; c) flocculating suspended solids (3) contained in the pre-treated POME using at least one polymer to produce flocculated suspended solids in the pre-treated POME; d) dewatering the flocculated suspended solids (4) as contained in the pre-treated POME to remove the flocculated suspended solids in the pre-treated POME using a belt press, filter belt, screw disc, multi disc screw, a decanter or any combinations thereof to produce a dewatered pre-treated POME; e) coagulating the dewatered pre-treated POME using inorganic and/or organic coagulants, followed bv a PH adjustment step using sodium hydroxide, hydrochloric acid, sulphuric acid, sodium chloride or anv combination thereof to produce coagulated suspended solids (5): f) removing the coagulated suspended solids (6) from the dewatered pre-treated POME using a gravity settlement means, a filtration means or a combination of both to produce a partially treated POME; g) delivering the partially treated POME to an electro-oxidation cell (7) comprising at least one electrode which is positively charged (anode), at least one electrode which is negatively charged (cathode) and at least one electrolyte to create an active oxidizing agent and to produce a treated POME; and h) removing precipitate and/or suspended solids from the treated POME (8) using a filtration means such as a bag filtration, a membrane filtration or a combination of both to produce a fully treated POME.

3C - The present invention provides a third variation of the first embodiment as follows;

A process for treating palm oil mill effluent (POME), the process including the steps of: a) cooling the POME (1) in a cooling pond from a temperature range of between 60° C to 90°C to a temperature range of between 20° C to 60°C to produce cooled POME; b) treating the cooled POME anaerobically (2) in an anaerobic pond to produce pre- treated POME; c) flocculating suspended solids (3) contained in the pre-treated POME using at least one polymer to produce flocculated suspended solids in the pre-treated POME; d) dewatering the flocculated suspended solids (4) as contained in the pre-treated POME to remove the flocculated suspended solids in the pre-treated POME using a belt press, filter belt, screw disc, multi disc screw, a decanter or any combinations thereof to produce a dewatered pre-treated POME; e) adjusting the PH of the dewatered pre-treated POME using sodium hydroxide. hydrochloric acid, sulphuric acid, sodium chloride or any combination thereof followed bv coagulation using inorganic and/or organic coagulants to produce coagulated suspended solids, followed bv a second PH adjustment step using sodium hydroxide, hydrochloric acid, sulphuric acid, sodium chloride or anv combination thereof to produce coagulated suspended solids (5): removing the coagulated suspended solids (6) from the dewatered pre-treated POME using a gravity settlement means, a filtration means or a combination of both to produce a partially treated POME; g) delivering the partially treated POME to an electro-oxidation cell (7) comprising at least one electrode which is positively charged (anode), at least one electrode which is negatively charged (cathode) and at least one electrolyte to create an active oxidizing agent and to produce a treated POME; and h) removing precipitate and/or suspended solids from the treated POME (8) using a filtration means such as a bag filtration, a membrane filtration or a combination of both to produce a fully treated POME.

Referring to Figure 7, the present invention provides a fourth embodiment as follows:

A process for treating palm oil mill effluent (POME), the process including the steps of: a) cooling the POME (26) in a cooling pond from a temperature range of between 60°C to 90° C to a temperature range of between 20° C to 60°C to produce cooled POME; b) treating the cooled POME anaerobically (27) in an anaerobic pond to produce pre- treated POME; c) flocculating suspended solids (28) contained in the pre-treated POME using at least one polymer to produce flocculated suspended solids in the pre-treated POME; d) dewatering the flocculated suspended solids (29) as contained in the pre-treated POME to remove the flocculated suspended solids in the p re-treated POME using a belt press, filter belt, screw disc, multi disc screw, a decanter or any combinations thereof to produce a dewatered p re-treated POME; e) adjusting the pH of the dewatered pre-treated POME (30) using sodium hydroxide, hydrochloric acid, sulphuric acid, sodium chloride or any combination thereof; f) removing suspended solids (31) from the dewatered pre-treated POME using a gravity settlement means, a filtration means or a combination of both to produce a partially treated POME; g) delivering the partially treated POME to an electro-oxidation cell (32) comprising at least one electrode which is positively charged (anode), at least one electrode which is negatively charged (cathode) and at least one electrolyte to create an active oxidizing agent or to produce a treated POME; and h) removing precipitate and/or suspended solids from the treated POME (33) using a filtration means such as a bag filtration, a membrane filtration or a combination of both to produce a fully treated POME. pH levels of the said process are as follows:

• pH level of step a) is less than 5.0 [The incoming wastewater is acidic in nature, and usually is at pH levels of less than 5.0. The first phase on the anaerobic digestion process is very rapid whereby the acid bacteria converts the organic components of the POME into simpler molecules (known as VFA) which is later digested to produce methane gas. This process of converting the organic components into simpler molecules depresses the pH levels to higher levels].

• pH levels of steps b) to d) is between 4.0 to 7.5, preferably 4.0 to 7.0 and most preferably 4.5 to 7.0 as methanogenic bacteria work the most effective in pH levels of between 7.0 to 7.5.

• pH levels of steps e) to h) is between 2.0 to 9.0, preferably between 2.0 and 7.0 and most preferably between 2.0 to 6.0. The range here is wide as there are several ways to approach steps e) and h) as these steps are flexible and depends on preference and cost / expenditure of a particular mill. During the coagulation step (without the additional step of pH adjustment), coagulation is done using coagulants such as ferric chloride which will bring the pH of the wastewater to a pH range of between 5.0 to 6.0. If the coagulation with the pH adjustment step using sodium chloride as an example, the pH level of the wastewater will be maintained in the range of between 5.0 to 6.0. During step g), the pH levels of the wastewater will increase, up to a maximum of 9.0. If hydrochloric acid is used as another example, pH will drop to about 2 prior to proceeding to step g). Again during step g), the pH levels of the wastewater will increase, up to a maximum of 9.0.

The hydraulic retention time (HRT) of step b) is between 3 to 80 days, preferably 40 days.

The VFA content of the pre-treated POME of step b) is below 500 ppm, preferably in a range of between 50 ppm to 300 ppm and most preferably in a range of between 100 ppm to 150 ppm. It is not preferred for the VFA content to be below 100 ppm as this is not a conducive environment and will cause starvation to the methanogenic bacteria and hence the anaerobic digestion process will be ineffective.

Using the electro-oxidation process, the retention time to create active oxidizing agent is in a range of between 5 minutes to 1,200 minutes (20 hours), preferably 30 minutes to 900 minutes (15 hours) and most preferably between 30 minutes to 600 minutes (10 hours) and the retention time to create treated POME is 1 minute to 600 minutes (10 hours), preferably 30 minutes to 300 minutes (5 hours) and most preferably 30 minutes to 180 minutes (3 hours). Hence, total HRT using this process would be around 40 days as compared to 100 days of the conventional POME treatment process. Referring to Figures 8 and 9. the present rnmnitenmavides a fifth embodiment as follows:

A process for treating palm oil mill effluent (POME), the process including the steps of: a) cooling the POME (34) in a cooling pond from a temperature range of between 60° C to 90°to a temperature range of between 20°C to 60°C to produce cooled POME; b) treating the cooled POME anaerobically (35) in an anaerobic pond to produce pre- treated POME; c) flocculating suspended solids (36) contained in the pre-treated POME using at least one polymer to produce flocculated suspended solids in the pre-treated POME; d) dewatering the flocculated suspended solids (37) as contained in the pre-treated POME to remove the flocculated suspended solids in the pre-treated POME using a belt press, filter belt, screw disc, multi disc screw, a decanter or any combinations thereof to produce a dewatered pre-treated POME; e) delivering the dewatered pre-treated POME to an electro-oxidation cell (38) comprising at least one electrode which is positively charged (anode), at least one electrode which is negatively charged (cathode) and at least one electrolyte to create an active oxidizing agent and to produce a partially treated POME; and f) removing precipitate and/or suspended solids from the partially treated POME (39) using a filtration means such as a bag filtration, a membrane filtration or a combination of both to produce a treated POME. pH levels of the said process is as follows:

• pH level of step a) is less than 5.0 [The pH levels of step a) is less than 5.0. The incoming wastewater is acidic in nature, and usually is at pH levels of less than 5.0. The first phase on the anaerobic digestion process is very rapid whereby the acid bacteria converts the organic components of the POME into simpler molecules (known as VFA) which is later digested to produce methane gas. This process of converting the organic components into simpler molecules depresses the pH levels to higher levels].

• pH levels of steps b) to d) is between 4.0 to 7.5, preferably 4.0 to 7.0 and most preferably 4.5 to 7.0 as methanogenic bacteria work the most effective in pH levels of between 7.0 to 7.5. · pH levels of steps e) to f) is between 2.0 to 9.0, preferably between 2.0 and 7.0 and most preferably between 2.0 to 6.0. The range here is wide as there are several ways to approach steps e) and h) as these steps are flexible and depends on preference and cost / expenditure of a particular mill. During the coagulation step (without the additional step of pH adjustment), coagulation is done using coagulants such as ferric chloride which will bring the pH of the wastewater to a pH range of between 5.0 to 6.0. If the coagulation with the pH adjustment step using sodium chloride as an example, the pH level of the wastewater will be maintained in the range of between 5.0 to 6.0. During step g), the pH levels of the wastewater will increase, up to a maximum of 9.0. If hydrochloric acid is used as another example, pH will drop to about 2 prior to proceeding to step g). Again during step g), the pH levels of the wastewater will increase, up to a maximum of 9.0. The hydraulic retention time (HRT) of step b) is between 3 to 80 days, preferably 40 days,

The VFA content of the p re-treated POME of step b) is below 500 ppm, preferably in a range of between 50 ppm to 300 ppm and most preferably in a range of between 100 ppm to 150 ppm. It is not preferred for the VFA content to be below 100 ppm as this is not a conducive environment and will cause starvation to the methanogenic bacteria and hence the anaerobic digestion process will be ineffective. Using the electro-oxidation process, the retention time to create active oxidizing agent is in a range of between 5 minutes to 1,200 minutes (20 hours), preferably 30 minutes to 900 minutes (15 hours) and most preferably between 30 minutes to 600 minutes (10 hours) and the retention time to create treated POME is 1 minute to 600 minutes (10 hours), preferably 30 minutes to 300 minutes (5 hours) and most preferably 30 minutes to 180 minutes (3 hours). Hence, total HRT using this process would be around 40 days as compared to 100 days of the conventional POME treatment process.

Electro-oxidation

Electro-oxidation process used for this present invention has remarkable ability in treating the pollutants as further described below:

^■ Effectively transforms non-biodegradable pollutants into non-toxic biodegradable substances by rapidly oxidizing a wide range of organic pollutants through generation of highly reactive groups of hydroxyl radical, (OH -);

Has efficiency in further reducing of the toxicity level in the POME that they can improve the biodegradability of organic compounds through the use of reactive radical; and ■ Remarkable ability of the reactive radical to react in a flash with the organic compounds that lead to the production of organic radicals whereby these radical in nature are reactive to the presence of oxygen.

There are two major methods in the electro-oxidation process, namely:

■ indirect oxidation; and

■ direct oxidation. In indirect oxidation, the organic pollutants can be eliminated by the oxidation. Indirect oxidation is the condition whereby a mediator is electro generated to carry out the oxidation - see Figure 10.

For direct oxidation, the pollutants are destroyed on the anode surface by the anodic electron-transfer reaction - see Figure 11.

Another important aspect of the electro-oxidation process is the existence / production of hydroxyl (OH ~) radicals whereby they are produced on the anode surface to enhance the rate of oxidation as it is a strong, non-selective oxidizing agent that reacts instantaneously with organic compounds viz. hydroxylation (oxidative degradation of organic compound in the air which converts lipophilic compounds into hydrophilic products that are more readily excreted) assisted by the addition of hydroxyl group to a non-saturated bond or dehydrogenation with the loss of hydrogen atom following a radical mechanism until their overall mineralization that converts the initial product into carbon dioxide, water and inorganic ions.

Additional information The POME is required to proceed to a cooling pond to cool down the POME from a temperature range of between 60° C to 90°C usually between 70°C to 80°C, to a temperature range of between 20°C to 60°C, preferably between 25°C to 35°C (as mesophiles are used for this present invention) before the POME proceeds to the anaerobic pond for anaerobic treatment. Anaerobic bacteria are basically methane- forming bacteria which are active in 2 temperature ranges, namely mesophilic range of between 20°C to 45°C and thermophilic range of between 50°C to 60°C. Mesophiles (or mesophilic bacteria) or thermophiles (or thermophilic bacteria) can be used as the anaerobic bacteria depending on preference. Temperature at this stage would depend on types of anaerobic bacteria used to ensure performance of the bacteria are not inhibited by unsuitable temperature. Hence, should be adjusted accordingly.

An acceptable and uniform temperature should be maintained throughout the anaerobic ponds as variations to the temperature can also affect the inhibition of the anaerobic bacteria. Hence, efficient mixing is required in the anaerobic ponds to ensure temperature is coherent throughout the anaerobic ponds for the most effective treatment of POME by the anaerobic bacteria of choice (also known as methanogenic bacteria). Methanogens are essentially microorganisms that produces methane as a by-product.

The reaction time to produce treated POME is in a range of between 1 minutes to 600 minutes (10 hours), preferably 30 minutes to 300 minutes (5 hours) and most preferably between 30 minutes to 180 minutes (3 hours). Based on trials and observations by our inventors, 3 hours should be sufficient to treat POME, however, if the POME contains organic content which is higher than normal (unnaturally high), more time would be required and can be adjusted and determined accordingly by the respective mills.

The electro-oxidation cell contains an electrical current in a range of between 5 amperes to 10,000 amperes, preferably in a range of between 100 amperes to 1,000 amperes and most preferably in a range of between 600 amperes to 2,000 amperes for 1,000 hires of POME.

Using the electro-oxidation process, the retention time to produce active oxidizing agent is in a range of between 5 minutes to 1,200 minutes (20 hours), preferably 30 minutes to 900 minutes (15 hours) and most preferably between 30 minutes to 600 minutes (10 hours) and the retention time to create treated POME is 1 minute to 600 minutes (10 hours), preferably 30 minutes to 300 minutes (5 hours) and most preferably 30 minutes to 180 minutes (3 hours).

The active oxidizing agent is chlorine, oxygen and/or hydroxyl ion (OH-), preferably chlorine. The chlorine produced has a concentration in a range of between 0% to 10%, preferably between 1% to 8% and most preferably between 6% to 8% (current industrial grade for sodium hypochlorite) For the purposes of this present invention, the oxidation process happens by introducing the hydroxyl ion (OH-) to POME to produce bio-products such as carbon dioxide and water.

The precipitate and/or suspended solids are metal oxides such as ferum oxide, zinc oxide, nickel oxide and others for the purposes of the present invention.

The filtration means of the present invention contains a pore size in a range of between 1 micron to 100 microns, preferably in a range of between 1 micron to 50 microns and most preferably in a range of between 1 micron to 10 microns. The ranges (as tested and investigated by the inventors) provided here are sufficient to filter out solids from the treated POME as if the solids are not filtered out, inaccurate BOD and COD readings will be produced.

The at least one polymer of the present invention can be in any form such as solution, powder, oil or water-based emulsions or any combinations thereof. Any forms can be used and works effectively for this present invention. The at least one polymer are polyacrylamide, polypropylene, polytannin, polyamines or any combination thereof. The quantity of the at least one polymer to the pre-treated POME is in a range of between 20 ppm to 300 ppm preferably in a range of between 50 ppm to 150 ppm and most preferably in a range of between 100 ppm to 150 ppm.

The at least one electrolyte of the present invention are such as sodium chloride, sodium sulphate, hydrochloric acid, sulphuric acid or any combinations thereof. The quantity of the at least one electrolyte to the partially treated POME is in a range of between 100 ppm to 10,000 ppm preferably in a range of between 500 ppm to 8,000 ppm and most preferably in a range of between 1,000 ppm to 6,000 ppm. The proposed ranges here have been determined by the inventors’ expertise and experience in this field, trials conducted, testing and observations done by the inventors with regards to the impact of the dosage of an electrolyte to the performance of the electro-oxidation cell, whereby higher dosage of an electrolyte will reduce retention time in the electro-oxidation cell and vice-versa. The selection would depend on preference and costing / expenditure / budget of an individual mill.

The electro-oxidation cell which consists of two electrodes (anode and cathode) exist only as anode and cathode plates or anode and cathode plates together with a contactor in between the anode and cathode plates for this present invention. The contactor used can be from materials such as activated carbon, zeolites, ion exchange resin or any preferred material which can enable transfer of surface charges (electrons) of the POME.

The surface area to volume ratio of the at least one electrode which is positively charged (anode) is in a range of between 0.001 m ² /L to 1 m ² /L, preferably in a range of between 0.001 m ² /L to 0.5 m ² /L and most preferably in a range of between 0.001 m ² /L to 0.2 m ² /L. “Surface area” means the area if the at least one electrode where the direct oxidation takes place. The bigger the surface area, reaction will be faster to work on the organic matters of the POME, hence, less retention time in the electro-oxidation cell and vice-versa. The selection would depend on preference and costing / expenditure / budget of an individual mill.

The distance between the at least one electrode which is positively charged (anode) and the at least one electrode which is negatively charged (cathode) is in a range of between 0.5 cm to 20 cm, preferably in a range of between 0.5 cm to 10 cm and most preferably in a range of between 0.5 cm to 5 cm. The distance between the electrodes in the electro- oxidation cell will determine the resistance in the cell, which would affect the voltage and power required for the electro-oxidation cell and process. The smaller the distance between the electrodes, the lower the resistance, voltage and power of the cell which results in lower operating cost, however, in order to obtain a smaller distance between the electrode plates, more plates are required to be installed which would see a rise in capital expenditure. The proposed ranges above are determined based on the inventors’ expertise and experience in this field, conduct of trials, observations and calculations by the inventors in balancing the operating cost and capital expenditure and what would be most optimum to be used for the present invention.

The inorganic and/or organic coagulants of the present invention are iron based coagulants, aluminium based coagulants or any combination thereof such as ferric chloride, aluminium sulphate, poly aluminium chloride (PAC), ferrous sulphate or any combination thereof, preferably ferric chloride. The quantity of ferric chloride to the pre- treated POME is in a range of between 500 ppm to 10,000 ppm, preferably in a range of between 2,000 ppm to 8,000 ppm and most preferably in a range of between 3,000 ppm to 6,000 ppm for pond of any size.

The fully treated POME is colourless, has a biochemical oxygen demand (BOD) value in a range of between 0 mg/L to 20 mg/L, preferably in the range of between 0 mg/L to 10 mg/L, most preferably in a range of between 0 mg/L to 5 mg/L and an ammoniacal nitrogen (AN) value in a range of between 0 mg/L to 20 mg/L, preferably in the range of between 0 mg/L to 10 mg/L.

Conventional means for POME treatment (as of current) is not able to produce fully treated POME which is colourless. Usually, the fully treated POME is dark brown in- colour. Hence, cannot be recycled to be used back in the milling process and only can be recycled to the mills for washing purposes or discharged into bodies of water. Summary

The present invention provides a series of POME treatment specifically an improvised process using electro-oxidation means in combination with other processes such as cooling process, coagulation, flocculation, dewatering, membrane separation, mixing POME with electrolytes, filtration (in any combination thereof), without the need for aerobic wastewater treatment or without the need for aerobic and anaerobic treatments. The proposed series of treatment are as per Figures 2, 3, 4, 5, 6, 7, 8 and 9 are generally summarised as follows: -

All options (as above) can be used to produce the final treated effluent which is colourless, has a biochemical oxygen demand (BOD) value in a range of between 0 mg/L to 20 mg/L, preferably in the range of between 0 mg/L to 10 mg/L, most preferably in a range of between 0 mg/L to 5 mg/L and an ammoniacal nitrogen (AN) value in a range of between 0 mg/L to 20 mg/L, preferably in the range of between 0 mg/L to 10 mg/L. Therefore, would depend on preference of an oil palm mill to choose the process of its choice depending on its capacity, budget, mode of operation, facilities and/or others.

In a normal processing conditions, coagulation comes before flocculation. However, for this present invention, the flocculation step comes before coagulation step (specifically for Options v), vi) and vii)). This is because the anaerobic solids are coagulated and forms small coagulates due to the microbial activity in the pond which allows the process to proceed directly to flocculation. After removal of flocculated solids, coagulation using ferric chloride will further precipitate out the balance impurities and coagulate them accordingly.

Option v) provides a process whereby most of the contaminants are removed during the coagulation step, hence, a lower retention time is required for the electro-oxidation process. Option v) allows the smallest capital expenditure and an user will be able to conduct the coagulation process with the additional pH adjusting step (if preferred), hence resulting in minimal retention time of the electro-oxidation cell. However, there will be more solid waste produced from this option due to the coagulation effect. Option v) would see a small capital expenditure and minimal maintenance cost as opposed to Options vii) and viii).

Option vi) is would see less use of coagulants as opposed to Option v), hence, lesser solid waste produced as opposed to Option v). The pH adjustment step would prepare the wastewater to be in its optimal pH condition before moving into the electro-oxidation cell for the next processes involved. Option vii) provides a process whereby most of the contaminants are removed via electro-oxidation process, before proceeding to the coagulation process. Production of solid waste (sludge) is also minimal using this option. Option v) would provide the cheapest capital expenditure, option vii) would provide the cheapest operating expenditure and option vii) would also provide the least generation of sludge.

Option viii) provides the most preferred route as there is no coagulation step required, which would result in the lowest operating expenditure and also ease of operations without use of coagulants. Options vii) and viii) are similar, except for the final step of not having the coagulation step. Electro-oxidation process itself is sufficient to remove contaminants from POME, hence, not necessary for a coagulation step to be in place. However, retention time for this step would be longer (additional 1 to 2 hours) than the step of using electro-oxidation and coagulation. Longer retention time would translate into bigger electro-oxidation cell (higher capital expenditure). This route is simple, provides lesser steps in the entire process and lowest in operating cost.

Options i) to iv) would allow for a methane avoidance process (without the need of having an anaerobic process involved), whereby, avoiding methane emissions to the atmosphere, hence reducing negative environmental impact. Options i) to iv) do not require any ponding system hence, which would result in reduced land area for POME treatment. The time for POME treatment (to produce treated POME) is also greatly reduced as the retention time is 1 day as opposed to 100 days via conventional means. Options iii) and iv) would allow recovery of additional oil from POME using membrane separation mechanism.

Benefits of the present invention are as follows: a) Aerobic process can be eliminated from the series of POME treatment which would result in reduced HRT and land area for POME treatment. b) Aerobic and anaerobic processes can be eliminated from the series of POME treatment which would further reduce HRT and land area for POME treatment. c) There would be reduction in capital cost pertaining to aerators and its maintenance at the aeration ponds. d) The present invention is able to produce chlorine via the electro-oxidation means in a concentration of between 0.1% to 10%, preferably 1% to 8% and most preferably 6% to 8% which can be sold as industrial grade sodium hypochlorite, instead of discharging the treated wastewater into bodies of water. e) The present invention is able to produce a fully treated POME for discharge into bodies of water which is colourless, has a biochemical oxygen demand (BOD) value in a range of between 0 mg/L to 20 mg/L and an ammoniacal nitrogen (AN) value in a range of between 0 mg/L to 10 mg/L in compliance with standards as set by the authorities.

0 Electro-oxidation process used for this present invention has remarkable ability in treating the pollutants as it is able to effectively transforms non-biodegradable pollutants into non-toxic biodegradable substances by rapidly oxidizing a wide range of organic pollutants through generation of highly reactive groups of hydroxyl radical, (OH ·). g) Less sludge / solids are produced using POME treatment using electro-oxidation as compared to conventional means, as the organic matter of POME is converted into carbon dioxide and only inorganic matter is converted into solids (i.e. sludge). Apart from that, there are no use of bacteria involved, hence no solid accumulation due to dead bacteria will be found using this process as opposed to aerobic process which produces high solid due to the microbe propagation rate. h) Using the electro-oxidation means, the retention time to create active oxidizing agent is in a range of between 5 minutes to 1,200 minutes (20 hours), preferably 30 minutes to 900 minutes (15 hours) and most preferably between 30 minutes to 600 minutes (10 hours) and the retention time to create treated POME is 1 minute to 600 minutes (10 hours), preferably 30 minutes to 300 minutes (5 hours) and most preferably 30 minutes to 180 minutes (3 hours). Hence, total HRT using this process would be around 40 days as compared to 100 days of the conventional POME treatment process for third to the fifth specific embodiments. i) Essentially, the introduction of this electro-oxidation process could also replace the current aerobic and anaerobic treatment processes, whereby, the HRT would be 1 day as compared to 100 days for conventional POME treatment means for the first to second specific embodiments. Using the electro-oxidation means, the retention time to create active oxidizing agent is in a range of between 5 minutes to 1,200 minutes (20 hours), preferably 30 minutes to 900 minutes (15 hours) and most preferably between 30 minutes to 600 minutes (10 hours) and the retention time to create treated POME is 1 minute to 600 minutes (10 hours), preferably 30 minutes to 300 minutes (5 hours) and most preferably 30 minutes to 180 minutes (3 hours). Apart from that, this is also methane avoidance process whereby no methane gas is released to the environment (i.e. reduce negative impact of release of greenhouse gas into the atmosphere via conventional means).

This present invention can be seen as a breakthrough in the palm oil milling process for POME treatment as such process (or combination or processes using electro-oxidation) has not been found to be used for POME treatment in the industry to-date. It is only known for electro-oxidation process to be used for treating for wastewater treatment, mainly for industrial effluents and membrane separation processes have been studied but not commercially applied in the industry.

It can be appreciateed that the present invention provides a POME treatment means for producing treated POME without the need of aerobic and anaerobic treatments which has not been found to be used and/or applied for POME treatment in the industry to-date. Ponding systems are largely used by the industry due to economic perspective, however, it is land and time intensive (i.e. requires long retention times and large treatment areas) and also releases large amount of methane gas into the atmosphere.

It can be appreciated that conventional means for POME treatment (to-date) is not able to produce fully treated POME which is colourless. Usually, the fully treated POME is dark brown in-colour. Hence, cannot be recycled to be used back in the milling process and only can be recycled to the mills for washing purposes or discharged to bodies of water. It can further be appreciated that this present invention is able to produce boiler feed water grade discharge effluent, whereby the boiler feed water grade discharge effluent can be recycled back to be used as dilution water, washing water at the mills and/or to create steam for sterilisation process in the palm oi milling process. This would directly transform to utilisation of water from bodies of water such as rivers be reduced by 50% when boiler feed water grade discharge effluent is produced by the process of this present invention.

It can also be appreciated that the present invention is able to produce chlorine via the electro-oxidation means in a concentration of between 0.1% to 10%, preferably 1% to 8% and most preferably 6% to 8% which can be sold as industrial grade sodium hypochlorite. 8% is the current industrial grade standard in the market. Sodium hypochlorite is essentially used as an oxidizing reagent with its commercial retail brand being chlorox. Hence, sodium hypochlorite can be produced instead for commercial use instead of treated wastewater for discharge into bodies of water.

Further, it can be appreciated that the parameters for the present invention are not obvious for a person skilled in the art and have been determined by the inventors based on numerous trials conducted, observations, discussions with combined expertise and experience in this field, which parameters and/or combination could not be determined without much efforts, testing and/or analysis or by just reviewing prior art documents in this field of interest.

Various modifications to these embodiments as described herein are apparent to those skilled in the art from the description and the accompanying drawings. The description is not intended to be limited to these embodiments as shown with the accompanying drawings but is to provide the broadest scope possible as consistent with the novel and inventive features disclosed. Accordingly, the invention is anticipated to hold on to all other such alternatives, modifications and variations that fall within the scope of the present invention and claims.

EXAMPLE

Example 1

This experiment was conducted using Process v). Anaerobic pond effluent was transferred to a buffer tank using screw pump. The anaerobic pond effluent was mixed with polymer at ratio of 150 ppm polymer powder to anaerobic pond effluent. Slow mixing was conducted in mixing tank to produce flocculated solid. The solid was dewatered using belt filter press. Filtered p re-treated POME was pH and charged adjusted using hydrochloric acid down to pH 2. The adjusted filtered pre-treated POME was treated in electro-oxidation cell for 3 hours followed by filtration at 10 microns by filter bag.

The resultant BOD was 6ppm and AN was 3ppm. Results are as per table below:

Water Analysis Test Report:

The fully treated POME is colourless, has a biochemical oxygen demand (BOD) value in a range of between 0 mg/L to 20 mg/L and an ammoniacal nitrogen (AN) value in a range of between 0 mg/L to 20 mg/L.

Example 2 Process with membrane:

10 litres of POME samples were collected from a palm oil mill after passing through a membrane system (permeate of the membrane system). 2 gram of sodium chloride (NaCl) as an electrolyte was added to the permeate and stirred until the NaCl dissolved completely into the permeate. The permeate then went through the electro-oxidation process in the electro-oxidation cell for a period of 5 hours, with a 5cm gap between the anode and cathode at 10 amperes (electrical current). The filtration process was done using a filter bag with a pore size of 1 micron. It is found that the treated POME is colourless, with BOD < 2 ppm and AN < 10 ppm. Process without membrane :

10 litres of POME samples were collected from a cooling pond at a palm oil mill. 8 litres of polymer (0.1% solution) were added to the POME samples. 2 gram of sodium chloride (NaCl) as an electrolyte was added to the POME asmples and stirred until the NaCl dissolved completely into the permeate. The POME samples then went through the electro-oxidation process in the electro-oxidation cell for a period of 4 hours. The filtration process was done using a filter bag with a pore size of 1 micron. It is found that the treated POME is colourless, with BOD < 2 ppm and AN < 10 ppm.