TECHNICAL FIELD

The present disclosure relates to a method for producing liquid and solid organomineral fertilizer. The present disclosure further relates to a system for producing liquid and solid organomineral fertilizer.

BACKGROUND

Traditionally, sewage sludge is disposed of by incineration or by processing into useful products such as fertilizer. For this, the production cycle is preceded by the WWS purification process using various technologies .

A known method for processing organic wastewater sludge includes mixing raw sludge with excess activated sludge, cavitation treatment with a cavitation number of 0.01-0.05, aerobic stabilization, settling, compaction and discharge of the treated sludge, its dehydration. The mixing of raw sludge and excess activated sludge is carried out at a ratio of 1 : 1 to 1: 3, cavitation treatment is carried out for 9-12 hours together with the process of aerobic stabilization with ejection aeration, many times, with the number of circulation cycles 3-10. Aerobic stabilization is carried out with the addition of above-sludge water to the processed mixture in an amount of 1/3 of the volume of the processed mixture, the processed sediment is unloaded from its lower compacted part in the amount of 1/3 of the volume of the processed mixture, dehydration is performed without preliminary aeration.

The disadvantage of this method is the duration of the cavitation treatment (at least 9 hours) and, as a result, significant power consumption. Another method for aerobic biological wastewater treatment includes mechanical treatment of source water and separation of solid sediment from it , settling waste water in a primary settling clarifier and separating raw sediment from a primary settling clarifier, aerobic biological treatment, settling waste water and activated sludge in secondary clarifier, removal of excess activated sludge from the secondary clarifier and removal of treated water .

The disadvantage is the duration of the WWS processing and the high energy consumption, as a result , the low economic efficiency .

Another known method for disinfection of WWS and preparation on its basis the raw materials suitable for the production of liquid and solid organomineral fertili zer comprises the following technological processes of WWS processing :

- disinfection by heat treatment with the aim of eliminating helminth eggs and pathogenic organisms and the primary destruction of organic matter ;

- cavi ta tion , in which chemical reactions for the transformation of substances are sharply accelerated due to the ioni zation of gases in the mixture . This occurs due to the grinding of the substances of the mixture due to shock waves formed when the bubbles collapse .

- ozona tion of WWS, in which treatment with ozone results in formation of peroxides of various substances presented in WWS , and guaranteed completion of biochemical processes ( controlled by biochemical oxygen demand parameters and gas liberation) with the formation of humic and carbon compounds ( carbon of humic acids , carbon of fulvic acids and tryptophan) .

The combination of heating, cavitation and ozonation makes it possible to achieve a technical effect - guaranteed disinfection of WWS and the creation of a product on its basis that is suitable for the production of fertili zer .

In said method the WWS is subj ected to

1 - composition equali zation,

2 - grinding,

3- disinfection by heat treatment , which is carried out at a temperature of 70 ° C with a heated substance holding for at least 20 minutes in the closed tank,

4 - cavitation treatment with an ultrasonic generator,

5- cooling to a temperature not exceeding 25 ° C,

6- supply for ozonation, which is carried out in a circulating ozonation tank by repeated circulation of water through an ej ector installed on a return pipeline , closed through the tank,

7 - passing through the technological block of enrichment with solutions of nitrogen, phosphorus , selenium and potassium containing substances ,

8 - feeding the mixture for water separation by centrifugation to obtain an enriched cake and a ready-made liquid organomineral fertili zer .

The problem with this solution is high energy consumption of disinfection and cavitation steps , which results in the low economic efficiency . The disinfection step is also time-consuming, as it requires prolonged heating and additional time for cooling down the WWS at a later stage .

SUMMARY

A method for producing organomineral fertili zer is disclosed . The method may comprise :

( a) providing a wastewater sludge (WWS ) ;

(b) subj ecting the WWS to disinfection using electrohydraulic shock to form a disinfected WWS ; and ( c) subj ecting the disinfected WWS to an ozone cavitation treatment to form organomineral fertili zer .

Further, a system for implementing the disclosed method to produce liquid and solid organomineral fertili zer is disclosed . The system may comprise : a) a loading device b) a reactor comprising a pulse voltage source for electrohydraulic shock c) a cascade ozone cavitation reactor d) a mixer in which the wastewater sludge is enriched with dry components e ) a hydrocyclone .

This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description . This Summary is not intended to identify key features or essential features of the claimed subj ect matter, nor is it intended to be used to limit the scope of the claimed subj ect matter . It is an obj ective of the present disclosure to provide a technical solution that enables the present invention . The obj ective above is achieved by the features of the independent claims in the appended claims . Further embodiments and examples are apparent from the dependent claims , the detailed description and the accompanying drawings .

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings , which are included to provide a further understanding of the embodiments and constitute a part of this specification, illustrate various embodiments . In the drawings :

Fig . 1 presents a schematic view of a system for producing an organomineral fertili zer according to one embodiment of the present disclosure . Fig . 2 presents a schematic view of an ozone cavitation reactor according to one embodiment of the present disclosure .

Fig . 3 presents a schematic view of a system for producing disinfected wastewater sludge (WWS ) according to one embodiment of the present disclosure .

DETAILED DESCRIPTION

The present disclosure relates to the production of fertili zer from wastewater sludge (WWS ) .

The technical effect of the method of the present disclosure is achieved due to the fact that the following technological processes of WWS processing are consistently applied :

- applying electrohydrauli c shock with the aim of eliminating helminth eggs and pathogenic organisms and the primary destruction of organic matter ; ozone cavi ta tion treatment , which ensures dispersion and efficient oxidation of WWS . As a result of ozone cavitation treatment , peroxides of various substances are formed in WWS , biochemical processes are guaranteed to be completed ( controlled by biochemical oxygen demand parameters and gas liberation) with the formation of humic and carbon compounds ( carbon of humic acids , carbon of fulvic acids and tryptophan) .

Electrohydraulic shock occurs upon pulsed electric discharges in a liquid . This process is accompanied by a sharp increase in pressure , the appearance of electromagnetic fields and the appearance of various types of radiation : ultrasound, light , heat , ultraviolet , X-ray, and any combination thereof . All this causes a transformation in the material composition of both processed solid materials and liquids , in which the electrohydraulic effect is carried out , affecting both their chemical and physical properties . Cavi ta tion is a process of formation, growth, and collapse of microbubbles in the liquid phase . The mechanical stresses arising from shock waves of cavity collapse and from flows and turbulence generated by pulsating cavities causes grinding of the particles , which increases their total surface area . When cavitation bubbles collapse , extreme temperatures and pressures occur locally for a very short time . These extreme conditions cause formation of free hydroxyl radical and related species at low concentration, and partial oxidation of organic substances as a result . Nevertheless , cavitation alone cannot be considered as efficient oxidation method due to very low yield of oxidative species . The different methods of inducing cavitation are known . One of them is acoustic cavitation (ultrasonication) , which occurs due to the passage of high frequency sound waves .

As used herein, "Ozone cavi ta tion treatment" is defined as a cascade process involving series of sequential cavitation and ozonation steps . During ozone cavi ta tion treatment WWS may be subj ected to cavitation prior to ozone treatment . This allows to break particle agglomerates and increase their overall contact area available for the following oxidation step . Also , during ozone cavi ta tion treatment cavitation may be applied after WWS is enriched with ozone . In this case , apart from increasing contact area of the particles , cavitation accelerates oxidation processes , due to the turbulence and intensive mass transfer, which promote dissolution of ozone and better distribution of oxidative species .

In one embodiment , a method for the production of organomineral fertili zer is disclosed, wherein the method comprises :

( a) providing a wastewater sludge (WWS ) ; (b) subj ecting the WWS to disinfection using electrohydraulic shock to form a disinfected WWS ; and

( c) subj ecting the disinfected WWS ozone cavitation treatment to form an organomineral fertili zer .

In one embodiment , the ozone cavitation treatment is characteri zed in that disinfected WWS is sequentially subj ected to a first cavitation, ozone enrichment , and a second cavitation .

In certain embodiments , the first cavitation comprises two or more sequential cavitation treatments .

In one embodiment , the cavitation is carried out using an ultrasonic generator .

In certain embodiments , the organomineral fertili zer is enriched with the compounds of nitrogen, phosphorus , potassium, selenium, or any combination thereof .

In one embodiment , organomineral fertil i zer is subj ected to phase separation in an appropriate device to form a solid and liquid organomineral fertili zer .

In one embodiment , system for implementing the method of the present disclosure to produce liquid and solid organomineral fertili zer comprises : a) a loading device b) a reactor comprising a pulse voltage source for electrohydraulic shock c) a cascade ozone cavitation reactor d) a mixer in which the wastewater sludge is enriched with dry components e ) a hydrocyclone .

In one embodiment , the cascade ozone cavitation reactor comprises at least three cavitators and one ozonator, wherein the outlet of one cavitator is connected to the ozonator, and the outlet of the ozonator is connected to the following cavitator . In one embodiment , system for implementing the method of the present disclosure to produce liquid and solid organomineral fertili zer comprises : a) a loading device configured to provide a waste water sludge (WWS ) ; b) a reactor configured to receive the WWS from the loading device and comprising a pulse voltage source configured to create electrohydraulic shock within the WWS ; c) a cascade ozone cavitation reactor configured to receive the WWS subj ected to the electrohydraulic shock and perform an ozone cavitation treatment on the WWS , d) a mixer configured to receive the WWS from the cascade ozone cavitation reactor and enrich the WWS with dry components ; and e ) a hydrocyclone configured to receive the enriched WWS from the mixer and separate the enriched WWS into liquid and solid fractions to form liquid and solid organomineral fertili zer .

In certain embodiments , the ozone cavitation treatment comprises a first cavitation, ozone enrichment , and a second cavitation, and wherein the cascade ozone cavitation reactor comprises at least three cavitators and one ozonator, wherein one cavitator has an outlet connected to the ozonator, and the ozonator has an outlet connected to the following cavitator ;

In certain embodiments , one or more of the cavitators are equipped with an ultrasonic generator .

The processing steps and the system for its implementation according to one embodiment of the present disclosure are shown in Fig . 1 , where they are indicated : 1- a loading device (1) that supplies the production line with wastewater sludge, for example, from a water utility system;

2- electrohydraulic reactor (2) , which performs pulsed-hydraulic action;

3- cascade ozone cavitation reactor (3) for the dispersion and oxidation;

4- a mixer in which the wastewater sludge is enriched with the compounds of nitrogen, phosphorus, selenium, and potassium substances ;

5- a hydrocyclone that separates the enriched mixture into a liquid (6) and a solid (7) fraction;

In one embodiment, the cascade ozone cavitation reactor (3) comprises at least three cavitators (3.1) and one ozonator (3.2) , wherein the outlet of one cavitator is connected to the ozonator and the outlet of the ozonator is connected to the following cavitator. The cascade ozone cavitation reactor (3) is presented in Fig . 2.

The combination of electrohydraulic shock and ozone cavitation treatment makes it possible to achieve a technical effect - guaranteed disinfection of WWS and the creation of a product on its basis that is suitable for the production of fertilizer.

The technical effect of the method or system of the present disclosure is to increase the efficiency of the production process of organomineral fertilizer from wastewater sludge. This technical effect is achieved, firstly, by reducing the duration of disinfection processes associated with the use of pulsed hydraulic processes, which leads to significant energy savings, and secondly, by using a cascade of cavitation reactors, after which the contact surface area of wastewater sludge particles increases significantly, which accelerates the process of its oxidation with ozone and salt enrichment .

In one embodiment of the present disclosure , the treatment time of the wastewater sludge (WWS ) from the entry point to the finished product is 30 minutes at most . The temperature regime is determined by the temperature of the wastewater sludge at the entry point and may vary depending on weather and climatic conditions . Temperature fluctuations during processing are not significant, 2 — 4 ° C, which distinguishes this technology for treating wastewater sludge from other energy-consuming technologies .

The presented method contains technological changes in the treatment of wastewater sludge-the replacement of the thermal disinfection process with a pulse - mechanical one , which reduces the time period for the destruction of carbohydrates , fat-like and protein substances with their transformation into soluble organic substances , with the simultaneous cessation of gas evolution, a sharp decrease in biological oxygen consumption and liquidation of pathogenic flora .

More specifically in the present method mechanical impact is carried out using the electrohydraulic effect . The electrohydraulic effect is based on the conversion of electrical energy into mechanical energy . This process is accompanied by a sharp increase in pressure , the appearance of electromagnetic fields and the appearance of various types of radiation : ultrasound, light , heat , ultraviolet , X-ray, and any combination thereof . All this produces a transformation in the material composition of both processed solid materials and liquids , in which the electrohydraulic effect is carried out , affecting both their chemical and physical properties . Methods of using electrohydraulic effect for obtaining high and ultrahigh pressures as a result of pulsed electric discharges in a liquid and devices for their use, are known to a skilled person, on the basis of which e.g. methods for purifying drinking and waste water has been developed.

The use of electrohydraulic effect increases the efficiency of disinfection by 8-9 times and reduces energy consumption by 15-20%. For disinfection of 1 m ³ of water around 1 kWh is usually spent.

In one embodiment, the method of production of liquid and solid organomineral fertilizer according to the present disclosure is carried out as follows. See Fig. 1 and Fig. 2 for details.

The sewage sludge from the water utility system is fed by a loading device (1) to an electrohydraulic reactor (2) where it is subjected to electrohydraulic shock, which destroys the bacterial forms.

Further, the sewage sludge treated by electrohydraulic shock enters the cascade ozone cavitation reactor (3) , which carries out the dispersion and oxidation of the sewage sludge. The specified reactor (see Fig. 2) is a series of at least 3 cavitators (3.1) connected at the input and output. The exit from the cavitator and the entry of the liquid from it into the ozonator (3.2) occurs after the second cavitator, where circulating ozonation is carried out with the passage of the liquid enriched with ozone through the third cavitator, which further increases the dissolution of ozone in the liquid by increasing the contact area of the particles and accelerates oxidation process.

The cyclic residence time of the sewage sludge may be approximately 25 minutes. During the residence time the sewage sludge may be returned to the ozonator (3.2) from the cavitator (3.1) at least once. In one embodiment, the treatment is continued until the concentration of ozone dissolution in the liquid reaches 50 mg / liter, which causes the essentially complete destruction of pathogenic flora, pathogenic bacteria, larvae, eggs of helminths. After processing the mixture in an ozone cavitation reactor, a liquid of a light, almost transparent color, odorless, due to the effect of strong oxidation, is obtained.

Further, the disinfected mixture of wastewater sludge enters the mixer (4) , where it is enriched with dry components such as nitrogen salts, phosphorus salts, selenium salts, and potassium salts to increase the concentration of nutrients in the solution.

After enrichment, the disinfected, nutrientrich solution enters the hydrocyclone (5) , where it is divided into two fractions: liquid-completely finished fertilizer (6) and enriched sediment, which is the raw material for the production of solid organomineral fertilizer (7) .

A distinctive feature of the implementation of the specified shock, is the occurrence of shock pressures inside the volume of any liquid, arising from the flow of electric impulse (spark, brush or other forms) discharges in it. Under the action of the arising discharges, considerable pressure is created inside the liquid volume, and with its sharp decline, the formation of a cavitation pocket with its subsequent closure. High pressure disrupts the vital activity of all biological objects in the container, by which disinfection of the liquid is achieved. When the cavitation bubbles collapse, the substances of the mixture are destroyed and fragmented due to shock waves generated during the collapse of the bubbles. During cavitation, chemical reactions for the transformation of substances are sharply accelerated due to an increase in temperature and the effect of gas ions on the mixture, that are formed during cavitation . In this case , the elimination of pathogenic flora occurs .

Upon completion of the WWS processing in the reactor, the mixture is sent for ozone cavitation treatment to the circulation ozonation tank . The saturation of the WWS solution with ozone is carried out by repeated circulation of water through an ej ector installed on the return pipel ine , closed through the tank . As a result of the treatment of the mixture with ozone , peroxides of various substances and carbon compounds , humic and sulfuric acids , tryptophan will be formed . Thus , biochemical processes and gas evolution are guaranteed to be completed . Then the mixture passes through the technological block for enrichment with salts of nitrogen, phosphorus , potassium, or selenium substances . After that , the liquid organomineral fertili zer is packed in containers for further transportation .

In the case when a solid organomineral fertili zer is produced, after enrichment , it is subj ected to phase separation, which may be carried out by centrifugation to obtain cake , which is a raw material for the production of granular organic and organomineral fertili zer and an enriched fraction of a liquid organomineral fertili zer of a weaker or more dilute consistency .

The technical effect of the disclosed solution is to increase the efficiency of the production process of organic fertili zer from WWS . The specified technical effect is achieved by reducing the duration of the disinfection process , which leads to significant energy savings .

The method described in the current specification has the added utility of increasing the efficiency of the production process of organic fertili zer from WWS . The added utility is achieved by reducing the duration of the disinfection process , which leads to significant energy savings .

In one embodiment , the system for implementing the method of the present disclosure to produce organomineral fertili zer comprises : a) a loading device configured to provide a waste water sludge (WWS ) ; b) a reactor configured to receive the WWS from the loading device and comprising a pulse voltage source configured to create electrohydraulic shock within the WWS ; c) a cascade ozone cavitation reactor configured to receive the WWS subj ected to the electrohydraulic shock and perform an ozone cavitation treatment on the WWS .

In one embodiment , the cascade ozone cavitation reactor comprises at least three cavitators and one ozonator, wherein the outlet of one cavitator is connected to the ozonator, and the outlet of the ozonator is connected to the following cavitator .

In one embodiment , one or more of the cavitators are equipped with an ultrasonic generator .

In one embodiment , the system for implementing the method of the present disclosure to produce organomineral fertili zer may further comprise : d) a mixer configured to receive the WWS from the cascade ozone cavitation reactor and enrich the WWS with dry components ; and e ) a hydrocyclone configured to receive the enriched WWS from the mixer and separate the enriched WWS into liquid and solid fractions to form liquid and solid organomineral fertili zer .

In one embodiment , a method for producing disinfected WWS is disclosed, wherein the method comprises :

( a) providing a wastewater sludge (WWS ) ; (b) subj ecting the WWS to disinfection using electrohydraulic shock to form a disinfected WWS ; and

( c) subj ecting the disinfected WWS to an ozone cavitation treatment .

In one embodiment , the ozone cavitation treatment is characteri zed in that disinfected WWS is sequentially subj ected to a first cavitation, ozone enrichment , and a second cavitation .

In certain embodiments , the first cavitation comprises two or more sequential cavitation treatments .

In one embodiment , the cavitation is carried out using an ultrasonic generator .

In one embodiment , a system for implementing the method of the present disclosure for producing disinfected WWS comprises : a) a loading device configured to provide a waste water sludge (WWS ) ; b) a reactor configured to receive the WWS from the loading device and comprising a pulse voltage source configured to create electrohydraulic shock within the WWS ; c) a cascade ozone cavitation reactor configured to receive the WWS subj ected to the electrohydraulic shock and perform an ozone cavitation treatment on the WWS .

In certain embodiments , the ozone cavitation treatment comprises a first cavitation, ozone enrichment , and a second cavitation, and wherein the cascade ozone cavitation reactor comprises at least three cavitators and one ozonator, wherein one cavitator has an outlet connected to the ozonator, and the ozonator has an outlet connected to the following cavitator ;

In one embodiment , one or more of the cavitators are equipped with an ultrasonic generator . In one embodiment, the method for producing disinfected WWS according to the present disclosure is carried out as follows. See Fig. 3 and Fig. 2 for details .

The sewage sludge from the water utility system is fed by a loading device (1) to an electrohydraulic reactor (2) where it is subjected to electrohydraulic shock, which destroys the bacterial forms.

Further, the sewage sludge treated by electrohydraulic shock enters the cascade ozone cavitation reactor (3) , which carries out the dispersion and oxidation of the sewage sludge. The specified reactor (see Fig. 2) is a series of at least 3 cavitators (3.1) connected at the input and output. The exit from the cavitator and the entry of the liquid from it into the ozonator (3.2) occurs after the second cavitator, where circulating ozonation is carried out with the passage of the liquid enriched with ozone through the third cavitator, which further increases the dissolution of ozone in the liquid by increasing the contact area of the particles and accelerates oxidation process.

After processing the cascade ozone cavitation reactor, the disinfected WWS (8) can be drained into receiving tanks for further use as process water.

In one embodiment of the present disclosure, the treatment time of the wastewater sludge (WWS) from the entry point to the finished product is 60 minutes (1 hour) at most. After processing for 1 hour in a volume corresponding to the production capacity of the equipment, the disinfected WWS can be drained into receiving tanks for further use as process water.

EXAMPLES

Reference will now be made in detail to various embodiments . The description below discloses some embodiments in such a detail that a person skilled in the art is able to utili ze the embodiments based on the disclosure . Not all steps or features of the embodiments are discussed in detail , as many of the steps or features will be obvious for the person skilled in the art based on this specification .

Example 1

The sewage sludge from the water utility system enters a loading device , which directs it for disinfection to the reactor equipped with a pulse voltage source in which a single electrical pulse discharge is carried out . The consequence of such a discharge is an electrohydraulic shock, which is a combination of two shocks : the main one , which occurs when the liquid is compressed and an additional "pushing" one , a cavity pocket i s formed, which occurs when the cavity is closed . The cycle of these two shocks can be repeated at the required frequency in accordance with the repetition rate of the discharges .

A distinctive feature of the implementation of the specified shock, is the occurrence of shock pressures inside the volume of any liquid, arising from the flow of electric impulse ( spark, brush or other forms ) discharges in it . Under the action of the aris ing discharges , considerable pressure is created inside the liquid volume , and with its sharp decline , the formation of a cavitation pocket with its subsequent closure . High pressure disrupts the vital activity of all biological obj ects in the container , by which di sinfection of the liquid is achieved . When the cavitation bubbles collapse , the substances of the mixture are destroyed and fragmented due to shock waves generated during the collapse of the bubbles . During cavitation, chemical reactions for the transformation of substances are sharply accelerated due to an increase in temperature and the effect of gas ions on the mixture , that are formed during cavitation . In this case , the elimination of pathogenic flora occurs .

Upon completion of the WWS proces sing in the said reactor, the mixture is sent to the cascade ozone cavitation reactor for ozone cavitation treatment . The WWS passes sequentially through two cavitators where it is subj ected to cavitation, after which it enters circulation ozonation tank . The saturation of the WWS solution with ozone is carried out by repeated circulation of water through an ej ector installed on the return pipeline , closed through the tank . The ozone enriched WWS then is directed to the third cavitator . As a result of the treatment of the mixture with ozone , peroxides of various substances and carbon compounds , humic and sulfuric acids , tryptophan will be formed . Cavitation treatment before and after enrichment of WWS with ozone increases contact surface area of wastewater sludge particles significantly, which accelerates the process of its oxidation with ozone and salt enrichment . Thus , after ozone cavitation treatment biochemical processes and gas evolution are guaranteed to be completed .

Then the WWS passes through the mixer, in which the wastewater sludge is enriched with dry components - salts of nitrogen, phosphorus , potassium, or selenium substances . After that , the liquid organomineral fertili zer is bottled in containers for further transportation .

In the case when a liquid and a solid organomineral fertili zer is produced, organomineral fertili zer is subj ected to phase separation, which is carried out by hydrocyclone to obtain cake , which is a raw material for the production of granular organic and organomineral fertili zer and an enriched fraction of a liquid organomineral fertili zer of a weaker or more dilute consistency .

Example 2

The sewage sludge from the water utility system enters a loading device , which directs it for disinfection to the reactor equipped with a pulse voltage source in which a single electrical pulse discharge is carried out . The consequence of such a discharge is an electrohydraulic shock, which is a combination of two shocks : the main one , which occurs when the liquid is compressed and an additional "pushing" one , a cavity pocket i s formed, which occurs when the cavity is closed . The cycle of these two shocks can be repeated at the required frequency in accordance with the repetition rate of the discharges .

A distinctive feature of the implementation of the specified shock, is the occurrence of shock pressures inside the volume of any liquid, arising from the flow of electric impulse ( spark, brush or other forms ) discharges in it . Under the action of the aris ing discharges , considerable pressure is created inside the liquid volume , and with its sharp decline , the formation of a cavitation pocket with its subsequent closure . High pressure disrupts the vital activity of all biological obj ects in the container, by which disinfection of the liquid is achieved . When the cavitation bubbles collapse , the substances of the mixture are destroyed and fragmented due to shock waves generated during the collapse of the bubbles . During cavitation, chemical reactions for the transformation of substances are sharply accelerated due to an increase in temperature and the effect of gas ions on the mixture , that are formed during cavitation . In this case , the elimination of pathogenic flora occurs . Upon completion of the WWS proces sing in the said reactor, the mixture is sent to the cascade ozone cavitation reactor for ozone cavitation treatment . The WWS passes sequentially through two cavitators where it is subj ected to cavitation, after which it enters circulation ozonation tank . The saturation of the WWS solution with ozone is carried out by repeated circulation of water through an ej ector installed on the return pipeline , closed through the tank . The ozone enriched WWS then is directed to the third cavitator . As a result of the treatment of the mixture with ozone , peroxides of various substances and carbon compounds , humic and sulfuric acids , tryptophan will be formed . Cavitation treatment before and after enrichment of WWS with ozone increases contact surface area of wastewater sludge particles significantly, which accelerates the process of its oxidation with ozone and salt enrichment . Thus , after ozone cavitation treatment biochemical processes and gas evolution are guaranteed to be completed .

After processing for 60 minutes ( 1 hour) in a volume corresponding to the production capacity of the equipment , the disinfected WWS can be drained into receiving tanks for further use as process water .

It is obvious to a person skil led in the art that with the advancement of technology, the basic idea may be implemented in various ways . The embodiments are thus not limited to the examples described above ; instead, they may vary within the scope of the claims .

The embodiments described hereinbefore may be used in any combination with each other . Several of the embodiments may be combined together to form a further embodiment . A method, or a system, disclosed herein, may comprise at least one of the embodiments described hereinbefore . It will be understood that the benefits and advantages described above may relate to one embodiment or may relate to several embodiments. The embodiments are not limited to those that solve any or all of the stated problems or those that have any or all of the stated benefits and advantages. It will further be understood that reference to 'an' item refers to one or more of those items. The term "comprising" is used in this specification to mean including the feature (s) or act(s) followed thereafter, without excluding the presence of one or more additional features or acts.