Method of Removing Organic Contaminants from Aqueous Compositions

This application is a continuation-in-part of my copending application, Serial No. 307,300, filed on September 30, 1981, and entitled "Organoclay Waste Disposal Method." The entire disclosure of this parent application is incorporated herein by refer¬ ence.

Background of Invention

Technical Field

This invention relates to a method for removing organic contaminants from aqueous compositions, and is particularly useful in the treatment of waste fluid.

Background Art

One of the major problem facing cities, chemical manufacturers, and industries using various chemicals, is waste disposal. More particularly, cities and industries are often faced with the disposal of aqueous compositions containing organic contaminants. Regula¬ tions make it impossible to simply dump such waste water into streams, even if such method of disposal were desirable. Various .methods have been proposed

^c -- ^{5 ■ ■} - - ^{» •} ' ^■ - -- -"_ .§__ i

for removing such contaminants from waste water, but they have been relatively expensive or inefficient. Therefore, the removal of contaminants from aqueous compositions, and in particular from waste water con- taining small amounts of contaminants, is a problem which has not been completely solved.

More particularly, municipal water treatment for removal of trihalo ethanes (THM's) resulting from the chlorination of drinking water and organic contaminants in ground water is a major problem for most water sys¬ tems in the United States. Currently, no economically satisfactory methods exist for removal of such organic moieties.

The issue of trihalomethanes as•a ^* focal point of chlorinated (or more appropriately halogenated) organic substances in public water supplies has been continuing for the past several years. Hundreds of research and review papers have been published on the subject and conferences have been held on chlorination, some pro- ceedings of which have been published by Ann Arbor Science.

Much concern about the production of trihalometh¬ anes, notably chloroform, dichlorobromomethane, dibro- mohloromethane, and, to a lesser extent, bromoform, in the process of disinfecting of drinking waters has resulted in the inclusion of monitoring for these compounds in proposed Federal drinking water standards. Also, a standard of 100 ug/ total trihalomethanes has been proposed (annual average) as well as requirements for the use of activated carbon to control the forma¬ tion of trihalomethanes. Final acceptance of the pri¬ mary drinking water regulations has been delayed partly by legal action in which the American Water Works Association (AWWA) has played a major role in opposi-

C"" T-T- - ^> _--— — - ----—- ^■ -. -_.t --- -.m-.

*_, . __■ _. _ _ _ ,_; _ ___ _χ _;j _______ 1

tion to the promulgated regulations.

The AWWA has maintained that insufficient scienti¬ fic evidence has been produced to justify the use of alternative disinfection technology relative to the at- tendant loss in consumer protection; or to justify the costs associated with the proposed with aqueous chlorine) removal. This approach in turn, is projec¬ ted to be more efficient than removal of THMs after production. While other prevention/removal techniques are possible, their present technological feasability is not fully demonstrated and the associated economics do not presently justify their use.

Still further, all surface water sources (i.e. lakes and rivers) and some groundwater employed for industrial as well as municipal purposes, contain a certain amount of naturally occurring organics, com¬ monly referred to as "humics." This naturally occur¬ ring humic portion is further divided into a humic and a fulvic acid portion. These moieties are not well defined, but in general the humic acid is composed of high molecular weight organic acids and the fulvic is considered to be the low molecular weight fraction. The humic contained in natural waters presents two types of problems, one in the industrial sector, the other in the municipal drinking water area.

The problems associated with humics in industrial feed waters is related to their effect on the life time of anion exchange resins employed to soften boiler feed water. The anion exchange resins are extremely expensive; their fouling by humics increases operation costs significantly. There is, therefore, a need for a pretreatment to remove humics.

Further, chlorination of drinking water has long been a method used to prevent the transmission of

SUBSTITUTE SHEET

- 4 -

disease from contaminated water. However, chlorination of waters containing bromide ion and natural organic compounds results in the production of chloro- and brom-organic compounds. It is now generally accepted that the chlorination of natural waters containing humic and fulvic acids produces not only volatile trihalomethanes (THMs), but also many other chlorinated aliphatic and aromatic compounds. The THMs are poten¬ tially carcinogenic compounds and the EPA has proposed a maximum level of 100 ug/L of total THMs in drinking waters. The toxicity of the less volatile halogenated organics has not been established; however, there has been concern over their potential activity.

Many different methods, such as macroreticular resins and granulated charcoal, have been tried to re¬ move either the precursors of, or the halogenated or¬ ganic compounds themselves, but such methods have only had limited success. There exists numerous methods for removing organic contaminants from aqeuous composi- tions, typically oil and water emulsions, see for ex¬ ample the following relevant U.S. Patents:

2,367,384 to Ty stra;

2,937,142 to Rios;

3,196,619 to Shock;

3,487,928 to Canevari;

3,528,284 to Skoglund et al;

3,986,953 to Beaucaire;

4,231,866 to Moser et al; and

4,279,756 to Weiss et al

More specifically, Tymstra describes a method for removing small quantities of water-immiscible organic oily impurities from water. The method consists of contacting the oily composition with an inert solid coated with a cation surface-active bonding agent.

The solid employed may be beach sand, mud flat deposits, silt, clay, limestone, silica, rice hulls, etc. The cationic surface-active bonding agent may be quaternary ammonium, phosphonium, arsonium, or primary, secondary, or tertiary organic amines or salts thereof. This reference does not teach or suggest the use of the specific organoclays utilized herein to remove or- ganic contaminants from aqueous compositions, nor the unexpected efficiencies of these clays.

Rios separates phenolic substances from aqueous solutions by contacting the aqueous solution with a clay adsorbent. The clay is previously treated by depositing carbonaceous material thereon, and then subjecting it to combustion regeneration to burn off the carbonaceous material.

Canevari separates droplets of oil from an aqueous phase, using a mixture comprising a sodium montmorillon- ite clay and an organic cationic agent or glycol. The organic cationic agent is preferably an amine. The mix¬ ture is applied as a flocculating clarifying solution containing from 1 to 5% of clay to water, and an effec¬ tive amount of the organic cationic agent or glycol. Beaucaire describes breaking an oil-water emulsion with waste-pickling acid solution, and thereafter con¬ verting the iron ions present in the waste-pickling so-

lution to magnetite particles which absorb the oil. The magnetite particles and oil absorbed thereon are sepa¬ rated from the solution leaving a clarified solution.

Moser et al separates organic and aqueous phases by treatment of the emulsions with diatomaceous earth at an elevated temperature.

Weiss et al describes the use of a finely divided particulate mineral or clay material, the individual particles of which have been treated. to produce a thin hydroxylated surface layer having a positive zeta po¬ tential at the adsorption pH.

None of the aforementioned references teach or suggest the use of organoclays to remove organic con¬ taminants from water. Additionally, organoclays are well-known in the art, see for example the following U.S. patents:

2,531,427 to Hauser;

2,966,506 to Jordan;

3,422,185 to -Kuritzkef;

3,974,125 to Oswald;

4,081,496 to Finlayson; and

4,105,578 to Finlayson et al

None of these aforementioned references teach or suggest the use of these organoclays to remove organic contaminants from water.

SUB —'

Summary and Objects of the Invention

A method is provided for removing organic contamin¬ ants from an aqueous composition contaminated therewith. The method comprises contacting the aqueous composition with a sufficient amount of organoclay for a sufficient amount of time to absorb organoclay admixture. The organoclay and aqueous composition are then separated from each other. The method is particularly useful for separating oily contaminants from water and toxic substance precursors, e.g. humic acid and other toxic organics (e.g. PCB's) from water.

Brief Description of Figures

FIGURE 1 shows the relationship of the logarithm of the distribution co-efficient of certain organic contaminants with the logarithm of their solubilities in water;

FIGURE 2 shows PCB column removal as described in Example 1;

FIGURE 3 shows column removal of dibromochloropro- pane from water as described in Example 1;

FIGURES 4 and 5 are commercial humic fluorescence breakthrough before and after backflush (Example 4);

FIGURE 6 is a plot of THM formation potential ( Example 4) ;

FIGURE 7 is a graph illustrating natural waters humic acid: fluorescence breakthrough (Example 4); -

SUBSTITUTE SHEET _/-£uRF

OMPI

A?- _* , ^vπρ0 .t

FIGURE 8 is a graph of natural waters total THM breakthrough (Example 4);

FIGURE 9 depicts resources reclamation groundwater: fluorescence, and TOC breakthrough curves (Example 4);

FIGURE 10 is a graph of fluorescence breakthrough for Preston Groundwater #2 (Example 4);

FIGURE 11 is a graph of fluorescence breakthrough for Florida Tap water (Example 4);

FIGURE 12 is a graph of fluorescence breakthrough for Preston Groundwater #2 minus Florida tapwater;

FIGURE 13 is a graph of Florida groundwater: sor- bent efficiences for humic removal;

FIGURE 14 shows polychlorinated biphenyl (PCB) col¬ umn removal by dimethyl di(hydrogenated tallow) ammonium bentonite, shown as a function of inlet and outlet con¬ centrations of PCB for exiting fluid volume (Example

ID?

FIGURE 15 shows polychlorinated biphenyl (PCB) col¬ umn removal by a dimethyl benzyl (hydrogenated tallow) ammonium bentonite form of organoclay, shown as a func¬ tion of inlet and outlet concentrations of PCB for exiting fluid volume (Example 11);

FIGURE 16 shows dibromochloropropane (DCBP) col¬ umn removal by the aforementioned benzyl and ditallow forms of organoclay, shown as a function of inlet and outlet concentr.ations of DBCP for exiting fluid volume

( Example 11 ) ; and

FIGURE 17 shows triohloroethylene (TCE) column re¬ moval by the aforementioned benzyl and ditallow forms of organoclay, shown as a function of inlet and outlet concentrations of TCE for exiting fluid volume (Example 11) .

Disclosure of Invention

Organoclays are well known in the art as exempli¬ fied by the aforementioned patents to Hauser, Jordan, Kuritzkef, Oswald et al, Finlayson, and Finlayson et al, the entire disclosures of which are incorporated herein by reference. In this invention, the term "organoclay" refers to various clay types, e.g. smec¬ tites, that have organo ammonium ions substituted for cations between the clay layers. The term "organo am¬ monium ion substituted" refers to a substituted ammo¬ nium ion in which one or more hydrogen atoms are re¬ placed by an organic group. The organoclays are essen¬ tially solid compounds that have an inorganic and an organic phase.

The preferred clay substrates for use in this in¬ vention are the smectite type clays, particularly the smectite type clays which have a cation exchange capa¬ city of at least 75 millequivalents per 100 grams of clay. Useful clays for such purposes include the naturally occuring Wyoming variety of swelling bento¬ nite and similar clays, and hectorite, which is a swel¬ ling magnesium-lithium silicate clay. The clays, are preferably converted to the sodium form if they are not already in this form. This can be effected, by a

. ⁸ .cT

- lo ¬

cation exchange reaction with a soluble sodium compound. These methods are well-known in the art. Smectite-type clays prepared synthetically can also be utilized, such such as montomorillonite, bentonite, beidelite, hector- ite, saponite, and stevensite.

The organoclays useful in this invention include those set forth in U. S. Patent No. 2,531,427 to Hauser. These organoclays are modified clays which exhibit in organic liquids,- some of those characteristics which untreated clays exhibit in water. For example, they will swell in many organic liquids and will form stable gells and colloidal dispersions.

Generally, the quaternary ammonium salt substitu¬ ted onto the clay has organic groups attached to the clay which will range from aliphatic hydrocarbon of from 1 to 24 carbons to aromatic organic molecules, such as benzyl groups that could have a host of groups substituted on the benzyl ring. The number of benzyl versus straight chain hydrocarbons substituted on the ammonium ion can vary from 3 to 0 (i.e. dimethyl dioc- tododecyl 0:2, methyl benzyl dioctododecyl 1:2, diben- zyl dioctobenzyl 1:1, tribenzyl octadecyl 3:1, methyl dibenzyl octodecyl 2:1). The amount- of alkyl ammonium salt substituted on the clay can vary between 0.5% to 50%.

In particular the preferred organoclay used in this invention comprises one or more of the following quaternary ammonium cation modified montmorillonite clays:

OMPI

R ₂ +

Rl—N—R Montmorillonite

R3

wherein R _j _ is an alkyl group having at least 10 carbon atoms and up to, for example, 24 carbon atoms, and preferably having a chain length of from 12 to 18 car¬ bon atoms; R2 is hydrogen, benzyl or an alkyl group of at least 10 carbon atoms and up to, for example, 24 carbon atoms, and preferably from 12 to 18 carbon atoms; and R3 and R4 are each hydrogen or lower alkyl groups, viz., they contain carbon chains of from 1 to 4 atoms, and preferably are methyl groups.

Other organoclays utilizable in the invention in¬ clude benzyl organoclays such as dimethyl benzyl (hy¬ drogenated tallow) ammonium bentonite; methyl benzyl di(hydrogenated tallow) ammonium bentonite; and more generally quaternary ammonium cation modified mont¬ morillonite clays represented by the formula:

Ri

R2—N—R4 Montmorillonite

R3

wherein Ri is CH3 or C6H5CH2 R2 ^is C6H5CH2; and R3 and R4 are alkyl groups containing long chain alkyl radicals having 14 to 22 carbon atoms, and most preferably where¬ in 20% to 35% of said long chain alkyl radicals contain

16 carbon atoms and 60% to 75% of said long chain alkyl radicals contain 18 carbon atoms.

The montmorillonite clays which may be so modified are the principal constituents of bentonite rock, and have the chemical compositions and characteristics de¬ scribed, for example, in Berry and Mason, "Mineralogy", 1959, pp. 508-509. Modified montmorillonite clays of this type (i.e _* organoclays) are commercially availa¬ ble from Southern Clay Products, Inc., Gonzales, Texas under such trade designations as CLAYTONE 34 and 40, and are available from NL Industries, Inc., New York, New York under such trade designations as BENTONE 27, 34, and 38. The preferred organoclays utilized in this invention, are the higher dialkyl dimethyl ammonium organoclays such as dimethyl di(hydrogenated tallow) dimethyl benzyl (hydrogenated tallow) ammonium oenton- ite; and ethylhydroxy ammonium organoclays such as methyl bis (2-hydroxyethyl) octodecyl ammonium benton¬ ite. The aqueous composition treated in this invention contain an amount of organic contaminant. Typical or¬ ganic contaminants are the chlorinated organic com- - pounds, e.g. DDT, BDD, DDE, 2, 4-dichlorophenol, tetra- chloroethylene, and polychlorobiphenyl contaminants and other organics such as benzene, toluene, methylene chloride, chloroform, 1, 2 dichloroethane, 1,1,1-tri- chloroethane, trichloroethylene, tetrachloroethylene, 2-nitrophenol, pentachlorophenol, dimethy phthalate, Lindane, Arochlorl254, ethyl benzene, HCP, parathion, dichlorobenzene, hexachlorocyclopentadiene, ethylpar- athion, 2, 4-dinitrotoluene, naphtalene, pyrene, oils, humic acid and other toxic substance precursors, di- bromochloropropane (DBCP), and organics chelated with metals. The latter mentioned chelated metal is a

metal that has formed a complex with an organic mol¬ ecule. These complexes are quite inert to normal chemical reactions.

In the method of this invention, a sufficient amount of the organoclay is contacted with the aqueous composition to absorb substantially all of the organic contaminants on the organoclay.

The capacity for sorption of or'ganics by the organ¬ oclays is from about 20% to 250% of the weight of the organoclay. The amount of organoclay utilized may thus range from about 40% to 500% by weight of the amount of organic contaminants.

The organoclay is thoroughly contacted with the aqueous composition. The temperature at which the or- ganoclay is mixed with the waste is not critical, how¬ ever, optimum removal efficiences are found in the range of 40° to 50° C. The contact time is an amount of time sufficient to absorb the contaminant on the organoclay, and generally ranges from about 10 seconds to about 10 minutes, depending on the amount of organo¬ clay, particle size, type, fluid velocity, etc.

The organoclay, upon contact with the aqueous composition, swells as the organic contaminant mole¬ cules are sorbed into and onto the organoclay. The organoclay additionally fixes the organic contaminant compounds through absorption involving partitioning of the organic molecules of the contaminant into the organoclay.

The organic molecules of the contaminant prefer- ably partition into the organic phase of the organoclay versus the aqueous phase or polar fluid phase of the fluid. The magnitude of organic partitioning of a given organic molecule into the organoclay over, for example, the a.queous phase can be predicted qualita-

i.*_. __-_ _Ϊ : « - <-> <-*. __-_- .

tively by the solubility of the organic molecule in the aqueous phase. That is to say, an organic molecule that is very insoluble, e.g. oil, in an aqueous phase will partition very strongly into the organoclay rela- tive to a more soluble organic molecule. This parti¬ tioning phenomenom also follows chromatographic theory which allows precise predictions of how organic mole¬ cules will migrate through a bed of organoclay. Figure 1 shows the linear relationship of distribution coeffic- ients for several key organic species with three types of organoclay. The distribution coefficients equal the amount of organic adsorbed in the clay divided by the amount left in solution times the volume of the solution divided by the mass of the clay. The aqueous solution contains the organics listed in Figure 1.

Generally, the amount in solution depends on solubility.

Several methods of contacting the organoclay with the contaminant containing aqueous composition include flow through columns and batch methods. The column method involves passing the aqueous composition through a packed column of organoclay. Another method is to contact the organoclay with the aqueous composition in a fluidized bed manner, i.e. an upflow of the aqueous composition through a bed of organoclay. Additionally, stirred beds of organoclay may be contacted with the aqueous composition.

The organoclay may be mixed with a particulate di¬ luent such as anthracite or may be utilized alone. Such methods of contacting particulate substances are well-known in the art, see, for example, the activated charcoal art.

In a batch method of contacting the organo-clay with the aqueous composition, the organoclay is added to the aqueous composition as a finely divided powder

-* i!_*c--" ^r τr—~ £--___ i ^{" r} OMPI

and after a sufficient amount of time is removed by the well-known methods of filtration, flocculation, flotation or centrifugation. In this mode of operation, the organic contaminants are sorbed on the organoclay and removed from the solution or the aqueous composi¬ tion when the organoclay is physically removed.

The organoclays may be used to remove natural or¬ ganics from water destined for use as drinking water. This is particularly important in areas where chlorina- tion is the method employed for disinfection. When chlorine is employed for this purpose, the natural or¬ ganics are chlorinated to form a family of compounds called trihalomethanes (THM) which have been shown to be- carcinogens. Removal of these organics from indus- trial boiler feed water is also important in lowering the cost of water softening since these organics will foul anion and cation exchange resins employed in the softening process.

Another area of great importance for the applica- tion of organoclays is for removal of organics from water wherein the organic is an oil. This problem appears in several major industrial sectors including oily condensate at petrochemical plants, oil emulsions utilized in rolling mills or machine shops using cut- ting oils, oil in water compositions at oil wells, and oil coming from power plants and other industrial plants.

Industrial chelated metals and solutions contain¬ ing the chelated metals may be pumped through columns or filters of organoclay. These columns can be either disposed of as a waste or the metals extracted for their use, since they have been highly concentrated.

The method of this invention thus provides several advantages one of which is an economical method of

εuBOT.τuTE SHΞET /^ R£A

_ __OMPI

. ,

^<A

removing organic contaminants from aqueous compositions. This yields substantial savings in disposal of the water and/or permits the water to be returned to the plant for further use. The organic contaminants/organ- oclays may be regenerated or incinerated.

The following nonlimiting examples illustrate sev¬ eral embodiments of the method of this invention.

Example 1

A small column of 2.1-cm diameter by 7.6 cm in height was employed to remove PCBs (polychlorobiphenyls) from water. The effluent and influent concentrations of PCB are given in Fig. 2. It can be seen that the or¬ ganoclay is very effective at removing the PCB from so¬ lution, with wide variation in influent concentration. A similar example is given in Fig. 3 for the remov¬ al of dibromochloropropane from water. Again the remov¬ al of DBCP is quite efficient.

Both of these compounds are carcinognic and their removal from water is a major concern. The organoclay utilized in both tests was dimethyl di(hydrogenated tallow) ammonium bentonite (occasionally referred to herein as "Form T" ) .

Example 2

This is an example of the removal of oil from oily condensate in a laboratory, pilot, and full scale plants at a petrochemical plant in Texas.

LABORATORY

At the laboratory scale, a plexiglass column was used measuring 1-3/4 inch I.D. and 2-1/4 inch O.D. and a length of 1 foot. In the experiment, a concentration of 2,000 ppm oil in water (Gulf Senate 460) was used to create a "worst-case" situation and to obtain a loading capacity for the pure sorbent. The organoclay — dimethyl di(hydrogenated tallow) ammonium bentonite (Form T) — was sieved to a 24-60 mesh size. The col- umn was packed using rubber stoppers at each end with a teflon plate inserted at the bottom of the column so as to prevent the sorbent from escaping, A peristaltic pump was used and a pressure gauge inserted so that a pressure drop could be monitered during the course of the run. The flow rate through the column was ini¬ tially set at 120 ml/min which corresponds to approx¬ imately 2gpm/ft2. The column was not completely filled with sorbent to allow for swelling; and the sorbent was fluidized in the column with water before the run was initiated.

An effluent sample was taken after each gallon to be analyzed for oil and grease. The influent was also sampled three times during the course of the run to document the coacentration. As the oily condensate composition was pumped through the column, a "wave front" moved through the sorbent as its absorption ca¬ pacity for the oil was saturated. Also, the initial zero pressure had increased to 8 psi after five gallons and to 30 psi after twelve gallons, with a correspond- ing flow rate of 80ml/min. which was rapidly decreas¬ ing. After fifteen gallons, the run was terminated. Removing most of the top layer of oil and sorbent did

not alleviate the pressure problems. .The final pres¬ sure was 48 psi and the flow rate was 40 ml/min. The effluent was still clear at the end of the run and approximately one inch of sorbent appeared unspent.

The majority of the samples were analyzed for oil and grease graviraetrically; however, a portion were analyzed using a Turner fluorimeter. These results appear in Table 1.

S _-_-*_> ^• a S _ t-» » _-_ *—>m . __--_! 1

Table 1. Laboratory Column Study - Organoclay Column 2000 PPM Influent

Sample Volume ppm Oil

Gravimetric Determination-

1 Gallon 3.5

2 Gallon 1.7

3 Gallon 3.0

4 Gallon <1

5 Gallon <1

6 Gallon 1.3

7 Gallon <1

8 Gallon 4.0

14 Gallon 2.3

15 Gallon 3.4

Influent #1 2310 Influent #2 2470 Influent #3 2280

Fluorimetry Determination

9 Gallon <1

10 Gallon <1

11 Gallon <1

12 Gallon <1

13 Gallon <1

The standard -deviation on this analysis is +4 ppm.

_-» i ~

Pilot

The initial test of a 4-inch diameter backwashable pilot unit containing the same organoclay as the labor¬ atory unit employed a mixture of 15% organoclay/85% anthracite. The column was 10 inches high and was run at 6.5 gpm/ft^ at an influent concentration of nominally 5 ppm oil. The column was run for 26 days. The pres¬ sures, flow rates, and oil content of the effluent are given in Table 2.

OMPI

Table 2. Results From Backwashable Pilot Unit

Day Time Flow Rate Pressure ppm Oil (gpm/ft ² ) (psig)

1 3:00 PM 6.5 7.0 0.8

Unit was started. Backwash performed well.

2 8:00 AM 6.5 7.0 0.8

11:00 AM 6.5 1.0 0.75

3 8:30 AM 6.5 1.0 0.4

6 10:30 AM 6.5 3.0 1.2

1:30 PM 6.5 5.0 0.8

1:35 PM Unit was backflu- ;hed. Pressure below O

1:35 PM 6.5 0.0 1.2

7 8:30 AM 6.5 0.5 0.8

8:30 AM 3.2 1.0 0.15

Increased to 6.5 and thιen took sample.

8 2:30 PM 6.5 0.0 0.8

9 8:30 AM 6.5 0.0 0.6 0 8:30 AM 6.5 0.0 0.5 3 10:30 AM 6.5 0.0 0.8 4 9:00 AM 6.5 0.5 0.8 5 9:00 AM 6.5 0.5 0.8 6 9:00 AM 6.5 0.5 0.8 0 8:30 AM 6.5 0.5 0.8 1 8:30 AM 6.5 0.5 1.25

Unit was backwashed.

2:30 PM 6.5 0.0 0.8 2 9:00 AM 6.5 0.0 0.8 3 8:30 AM 6.5 1.0 0.8 4 9:00 AM 6.5 0.0 0.8 7 — — - -

•_Jr5 irl ?.^_*

Full Scale

The final experiments were conducted at full scale. The same organoclay was mixed with anthracite in a 1:3 ratio and was loaded into a seven-foot diameter column with a bed depth of 18 inches. The unit was run for 50 days. The influent concentration of oil was approxi¬ mately 4 ppm but varied from 2 to greater than 25. The normal flow rate was 6.5 gpm/ft ² but went as high as 9.75 gpm/ft ² . The effluent averaged 0.6 ppm with the highest value of 4.0 ppm during extreme upsets in both flow rate and oil concentration.

It is clear from these examples that organoclays can be utilized very effectively to remove oil from water.

Example 3

All of the aforedescribed examples of applica¬ tions of the organoclay for removal of organics from water have been of the column type. An example of or¬ ganoclay applied to removal of organics from water in a batch mode is the injection of organoclay into a disolved air flotation unit (DAF). These devices em¬ ploy microscopic air bubbles to float suspended or col¬ loidal particles from solution. These devices remove gross amounts of oil from water. Table 3 contains results for removal of oil from oily condensate in a 600 gpm DAF with/influent oil con¬ centration of approximately 60 ppm. The organoclay dose was about 90 ppm.

r--s

SliOϋHi ^' --- £_,* _r_r~~ϊ- ^* f* TU ^E - ?

O PI wipo

- 23 -

Table 3. Removal of Oil in a Full Scale DAF Unit

Time of Day DAF Effluent Oil Concentration (ppm]

9:00 p, m.

12:01 a.m. 0.8

1:00 a.m. 0.8

3:00 a.m. 0.5

5:00 a.m. 0.5

7:00 a.m. 0.6

Normal DAF operation, using standard floculation methods, yields effluent of 3 to 4 ppm oil. This would indicate superior removal by utilizying organoclay.

e>! 5rΓ__?,c-r. i .. _ __. ^' BΛ3 ^' R£A

OΛΪPI

. Λ ^r -m_ WIPO O

Example 4

Analytical Procedures

Form T - dimethyl di(hydrogenated tallow) ammonium bentonite organoclay was used in experiments designed to observe removal of humics and other natural organics from various water sources. A column of 2.1 cm internal diameter X 8.1 cm in length was slurry-packed with un- sieved organoclay for commercial humic absorption studies. The commercial humic, Chemelog Lot No. 106774, was dissolved in low organic water at a concentration of approximately 86 mg/liter. The low organic water was prepared by taking deionized water and distilling it from a basic potassium permanganate solution.

A flow rate of approximately 2 mL/min (0.14 gallon per minute/ft ² ) was used for the commercial humic study. Fractions of approximately 20 to 25 mL each were collec¬ ted in test tubes using a Buchler Model 200 fraction collector. The volume and humic acid concentration by flourescence were measured for each tenth tube and an average volume for the ten tubes was calculated. The humic acid concentration from the column was followed by the use of a Turner fluorometer. The excitation filter used was Corning #7-60 which has a maximum at approximately 360 n . The emission filter used was a #48 with a maximum of approximately 465 nm. A series of solutions of known concentrations of humic acid were prepared and a standard fluorescence curve was gen¬ erated. This curve was found to be linear across the humic acid concentration range of 10 mg HA/L to 0.5 mg HA/L water.

>ϊ_jL_> 5 _ _. . _- I

Every one-hundredth fraction from the commercial humic was collected and retained for total trihalo eth- ane (THM) analysis. Total THM analyses were performed by chlorinating the collected fractions at 10 mg/L Cl with a chlorine solution of known concentration. The chlorine solution was prepared by bubbling chlorine gas through a basic water solution. Standardization of the chlorine solution was by ASTM Method 114A, Iodometric Method. Chlorinated samples were allowed to incubate at room temperature seven days prior to anaylsis. The THM's were analyzed by GH/Hall detector using the purge and trap methodology. All THM samples are quenched with sodium thiosulfate prior to being analyzed. ■ In order to test the validity of the measurements em- ploying synthetic humic waters, several natural waters containing large amounts of humics were obtained. These waters included Black lake water from Virginia, three groundwaters from Miami, Florida, and a tap water sample from Miami, Florida. Identical columns of 2.1 cm internal diameter X

4.2 cm length of Form T organoclay were slurry packed for each of the five natural waters. Each was washed with from 2 to 4 liters of organic-free water prior to starting the sample water. A sorbent particle size of 5.0 to 120 mesh was used for Preston Groundwater #1 and Black Lake Water. Flow rate through these two columns was 2 mL/min or 0.14 gpm/ft ² . Particle sizes of the sorbent used for the Florida Tap, Preston Groundwater #2 and Resources Reclamation Groundwaters were 60 to 120 mesh. The flow rate through these three columns was 3mL/rain or 0.21 gpm/ft ² . The Florida water (Preston Groundwater #1) and Black Lake Water were chlorinated at 10 mg/L and 50 mg/L Cl, respectively. The remaining three wa'ters were not chlorinated, but the Preston

c.: ? _S ϊ_> _ I f --J SHEET

Groundwater #2 and Resources Reclamation Groundwaters were chlorinated at the 20 mg/L Cl level or higher. Fluorescence measurements and other conditions for the natural waters were the same as those reported for the humic acid study.

Results and Discussions

Synthetic Humic Solution

A synthetic humic solution was prepared by dissolv¬ ing a known quantity of commercially available humic in organic-free water. This solution was then used to determine the feasibility of humic acid removal by Form T organoclay. A column of unsized organoclay was slurry-packed in water and rinsed well with organic-free water before the humic solution was passed through the column.

The humic solution was passed through the sorbent column at approximately 2 mL/min continuously for sever¬ al weeks. The empty bed volume of the column was ap¬ proximately 26 mL allowing for calculation of the num- ber of column volumes passed through the column. Fluor¬ escence measurements were made at regular intervals on column effluent in order to follow the breakthrough of the humic acid.

The results of the humic acid breakthrough study are shown in Fig. 4. The maximum fluorescence break¬ through observed was 13 percent of the initial concen¬ tration at approximately 2800 column volumes. The column was observed to become increasingly darker as humic acid accumulated on the sorbent. At 2905 column volumes, the humic acid flow was discontinued due to

severe flow reduction. The column was backflushed and rinsed with organic free water before resuming the humic flow. The level of fluorescence in the organic- free water rinse was not observed to go quickly to zero indicating the humic acid was not being removed from the sorbent.

The flow characteristics were restored by the back- flush and the humic water flow resumed. The fluor¬ escence breakthrough after treating the column is shown in Fig. 5. The level of fluorescence was never zero again but stayed constant at about five percent up to 2000 column volumes. At this point, the level slowly began to rise to a maximum of about 25 percent break¬ through at 2900 column- volumes at which point the flow was discontinued. Again, the column was observed to be very dark with the absorbed humic acid, and flow was restricted. The level of removal is extremely high in comparison to activated charcoal.

Samples saved for total THM analysis were chlorin- ated at 10 mg cl/L and allowed to incubate for seven days. A plot of the THM formation potential is shown in Fig. 6. Since the solution used was prepared from commercial humic and organic-free water, there was no bromide ion present to form brominated organics. There- fore, only chloroform was observed. The level of chlor¬ oform was found never to exceed 25 percent of that formed from the chlorination of the original influent humic acid solution. this fact indicates (1) that the sorbent is doing a good job in removing THM precursors from commercial humic solutions and (2) that that fluor¬ escence is a good indicator of the amount of material coming through the column.

An experiment in removing the humic from the spent column was then attempted. The column was vigorously

^_?^- _*

backflushed with deionized water. A small portion of the color was removed, but the humic appeared to be bound to fine particles of the sorbent material. The column was then backflushed with four liters of 0.01 N NaOH solution. The first liter of NaOH solution flush was very dark indicating removal of some humic. How¬ ever, the third and fourth liters of NaOH were relative¬ ly clear. The column itself remained very dark and appeared as if about 10 percent or less of the humic was removed by the NaOH backflush.

Natural Waters - Black Lake and Florida Groundwaters (Preston Groundwater #1)

Two natural waters were obtained; one from Black Lake, Virginia, which had a dark brown color and a TOC of 10.6 ppm and the second from a Florida ground- water (Preston Groundwater #1) with a yellow-orange color and a TOC of 5.6 ppm. These waters were passed through identical 2.1 cm diameter x 4.2 cm columns with an empty bed volume of 14 mL. The flow rate was approx- imately 2 mL/min.

The fluorescence breakthrough curves for these two waters are shown in Fig. 7. Agreement between the two curves is very good despite the difference in TOC value between the two waters. It should be noticed that well over 1000 column volumes of each water passed through the columns before 50 percent fluorescence breakthrough was obtained. The Form T organoclay appears to be very effective in removing the organics form the water; par¬ ticularly when compared to other potential sorbents. Fractions were collected from each of the columns for total THM analyses. The results from the Florida

SU _Ϊ -S _ _ - —• . £-. *_#---»—.J

water chlorination are shown in Table 4 with the Black Lake water chlorination results shown in Table 5. It is very interesting to follow the formation of the bro in- ated THM's. Very little brominated species were formed from the fractions collected up through 400 to 500 col¬ umn volumes. Subsequently, there follows a sharp rise to the conclusion that the bromide ion is being selec¬ tively removed from the water by the sorbent. The bro¬ mide ion then "breaks through" and becomes a factor in THM formation. A plot of total THM breakthrough for both waters is shown in Fig. 8. The Florida water fol¬ lows the fluorescence breakthrough very well. The Black Lake water has a higher initial total THM break¬ through than fluorescence but at about 1600 column vol- umes the agreement is very good. The value for Co in Fig. 8 in the THM value was obtained by chlorinating the raw water.

Regeneration of both columns was attempted by flushing with first deionized tap water followed by dilute NaOH solutions. Backflushing the Florida col¬ umn with deionized tap water removed a very yellow fraction for the first 500 mL. Visible color removal continued until 1.5 to 2 liters of water had been passed through the column. The column was rinsed with organic-free water and the Florida water restarted. Fluorescence breakthrough occurred within 10 column volumes. The Florida water column was then rinsed with 500 mL of 0.01 NaOH followed by one liter of 0.01 - N NaOH. The column was rinsed with deionized water until the effluent pH returned to the 6.5 to 7.0 range. The Florida water was restarted and 40 percent break¬ through was observed immediately. The fluorescence breakthrough was 75 percent at 64 column volumes and 82 percent at.18 column volumes indicating very little

U_3--. 2 _ _ U _ !_. i-Si s 1

regeneration of column capacity had occurred.

The Black Lake column also was rinsed with deion¬ ized water, 0.001 N NaOH and 0.01 N NaOH solutions. Each rinse resulted in very dark solutions coming from the column for a short time before the effluent began to clear. The column was restored with deionized water and Black Lake water started again. The fluor¬ escence breakthrough started at about 44 percent and then leveled off at 53 to 55 percent up to 350 column volumes. Some of the capacity of the column has been restored, but it was not restored to the original level. A few batch extractions with 0.1 and 1M NaOH indicate much higher extraction efficiences indicating regeneration feasibility.

w C _M - SI EET

Table 4. Results of Black Lake Water Chlorination* - Total THM'S

Concentration (ppb)

Fraction Column Volume CHCl-^ CHBrCl _? CHBr ₉ Cl CHB TTHM's C/Co X 100

5 15 102 4.2 0. ,1 107 7.3

6 100 306 9.6 2. ,4 318 21.9

CO

^« « ^' 8 265 357 8.9 0. .2 366 25.2

"i 100 481 512 9.5 522 36.0 ^■ " ^• _ 300 800 571 57 8, .6 637 43.9 ϊ-1 I

500 1090 720 71 9, .0 800 55.1

__ 800 1382 601 69 12 .0 682 47.0

PI 1025 1662 875 75 7; ;5 956 65.9

Raw Black 1400 49 2.2 1451 Lake Water

Table 5. Results of Florida Water Chlorination* Study - Total THM'S

Concentration (ppb)

Fraction Column Volume CHC1 ₃ CHBrCl ₂ CHBrCl ₂ CHBr ₃ TTHM C/C< 0 X 100

5 15 39.0 1. 8 0. 4 41 6.1.

24 72 53.3 2. ,3 .__ _* "*"*— 56 8.2 36 229 55.4 1..7 ,..,.— 57 8.5

100 393 37.4 11. ,0 0. 7 49 7.3

200 547 28.0 45 48 24 144 21.3 300 704 27.2 57 66 46 197 29.1 l

450 926 62.7 43 25 130 19.3 t

600 1158 108 46 25 4 183 27.1 pi 800 1428 150 56 31 5 232 35.8

1000 1829 273 53 17 2.0 345 51.0

1200 2158 207 61 26 1.7 295 43.7

1400 2621 346 67 23 2.1 438 64.9

Natural Waters - Preston Groundwater #2 Florida Tap Water and Resources Reclamation Water

Three water samples from Florida were obtained for column studies. Each was passed through identical 2.1 cm diameter X 4.2 cm columns at flow rates of ap¬ proximately 3 mL/min.

The fluorescence breakthrough curve for the Re¬ sources Reclamation Water is shown in Fig. 9. This water is very yellow in color and has a relatively high TOC content at 17 ppm. Breakthrough occurs for this water much earlier, approximately 500 column volumes compared to 2500 column volumes for the previ¬ ous waters; presumably due to the high organic content. As can be observed from Fig. 9, the agreement between total organic carbon (TOC) content and fluorescence is very good. This observation indicates that fluorescence is a good means of following natural organics in water.

The fluorescence breakthrough curve for the Pres¬ ton Groundwater #2 is shown in Fig. 10. This water is from the same source as the Florida water discussed in the previous section. It has a much lower TOC content at 5.6 ppm than the Resources Reclamation Groundwater. Breakthrough is much slower than the Reclamation water with 60 percent breakthrough at 1500 column volumes. The fluorescence breakthrough curve for the Florida Tap Water produced from Preston Groundwater #2 is shown in Fig. 11. This water has very little color and lower TOC. It has been chlorinated and has a residual chlor¬ ine level of 1 to 1.5 ppm. The initial relative fluor- escence is much higher than that seen in the ground- water. However, at 2600 column volumes, the column effluent fluorescence is less than 70 percent of the

__.___ »_P.. . e _„ _ i ;U '

«w- -____ j

influent water fluorescence.

The Preston groundwater is treated with alum to re¬ move approximately forty-five percent of the organics. This type of treatment preferentially removes the high molecular weight humics leaving mainly the low molecular weight fulvics. This would indicate that the humic breakthrough curve for Preston groundwater reproduced in Fig. 12 is most probably the combination of two breakthrough curves. If the breakthrough curve in Fig. 11 for the Miami tap water is assumed to be 100% fulvic acid and is subtracted from the Preston groundwater curve in Fig. 12, the resulting curve could represent the true humic acid fraction breakthrough. This curve more closely resembles what would be expected from true chromatographic behavior.

Conclusions

Dimethyl di( ydrogenated tallow) ammonium benton¬ ite organoclay has been determined to be very effective in the removal of humic acids (i.e., trihalomethane precursors) ^' . It has a very good capacity for the re¬ moval of the humic species. Based on the Resources Reclamation Water TOC of 17 ppm and a breakthrough of 550 column volumes, the capacity of the same organoclay is approximately 0.2 g of organic carbon per 10 g of dry sorbent. Since humic materials are approximately

40. to 50 percent carbon, the capacity of the organoclay is approximately 0.5 g of humics per 10 g of dry sor¬ bent. By comparison, the capacity of Amberlite resin would be approximately the same as this organoclay since the resin only removes 50 percent of the organics from the water. This organoclay, however, would be the pref¬ erable sorbent as it removes much more of the organic

__ -BU E T

SUBSTITUTE SHEE . OMPI

material through the first 1500 column volumes than the Amberlite resin. (See Figure 13).

Example 5

Several batch sorption experiments have been per¬ formed with two forms of higher dialkyl dimethyl organ¬ oclay and compared to untreated montmorillonite sorp¬ tion. These have been conducted with 100:1 solution to solid ratio. The following tables 6, 7 and 8 are a summary of these studies showing results from batch equilibration sorption studies of an untreated montmor¬ illonite, CLAYTONE ^® 34 and CLAYTONE ^® 40, respectively.

^■ B JREA

SUDST.TUTE SHEET f . OMPI o

Table 6.

24 Hours Batch Equili¬ 48 Hours Batch Equili-

Inlet Con¬ brations Concentration bration Concentration centrations Concentration Amount Blank Amount Blank

Organic Spiking Level in Blank Recovered (ppb) % Recovered (ppb) % Species (ppb) (ug/1) (ppb) (ug/1) (ppb) (ug/1) (ug/1) Sorbed (ppb) (ug/1) (ug/1) Sorbed

c Aroclor 1254 3.65 0 4.95 0 0 13 0 0

Q p,p'-DDT 0.88 0 0.82 0 7 0.96 0 0 -1 o,p'-DDT 1.77 0 2.11 0 0 2.16 0 0 p,p'-DDD 0.75 0 0.75 0 0 0.88 0 0 o,p'-DDD 0.43 0 0.46 0 0 0.36 0 16 ⁽ 0 p,p'-DDE 0.56 0 0.68 0 0 0.86 0 0 I ω a,

PI o,p'-DDE 0.17 0 0.20 0 0 0.15 0 12 l 2,4-Dichloro- phenol 18,000 11,000 0 39 11,000 39 Tetrachloro- ethylene 318 0.20 278 2.10 13 331 0.70 Benzene 1.35X10 ⁵ 0 1.35X105 0 0 Toluene 5.4 Xlθ4 0. 4.54X104 8 16 Methylene

Chloride 5.12X10 ⁵ 4.40X10 ⁵ 14

Table 7.

24 Hours Batch Equili¬ 48 Hours Batch Equili¬

Inlet Con- Concen- brations Concentration bration Concentration centrations tration Amount Blank Amount Blank

Organic Spiking Level in Blank Recovered (ppb) % Recovered (ppb) %

phenol 18,000 200 99 200 99 Tetrachloro- ethylene 318 0.20 ^• 25 0.3 92 24 0.2 92 Benzene 13.5X105 0 5400 0 96 Toluene 5.4X10 ⁴ 0 2160 0 96 Methyl Chloride 5.12X10 ⁵ 1.08X10 ⁵ 79

Table 8.

24 Hours Batch Equili¬ 48 Hours Batch Equili¬

Inlet Con- Concen- brations Concentration bration Concentration centrations tration Amount Blank Amount Blank

Organic Spiking Level in Blank Recovered (ppb) % Recovered (ppb) % Species (ppb) (ug/1) (ppb) (ug/1) (ppb) (ug/1) (ug/1) Sorbed (ppb) (ug/1) (ug/1) Sorbed tfi m Aroclor 1254 3.65 0 0 0 100 0 0 100 t P _. P'-DDT 0.88 0 0 0 100 0 0 100 o,p'-DDT 1.77 0 0 0 100 0 0 100 e: p,p'-DDD 0.75 0 0 0 100 0 0 100

PI 0,p'-DDD 0.43 0 0 0 100 0 0 100 I p,p'-DDE 0.56 0 0 0 100 0 0 100 ∞ I rπ o,p'-DDE 0.17 0 0 0 100 0 0 100

2,4-Dichloro- phenol 18,000 200 99 200 99 Tetrachloro- ethylene 318 0.20 27 0 . 92 25 0.30 92 Benzene 1.35X105 0 3420 0 76 Toluene 5.4 X10 ⁴ 0 1620 0 97 Methylene Chloride 5.12X10 ⁵ 1. 13X10 ⁵ 78

It can be seen that extremely efficient removal occurs for all of the listed organices with the organo¬ clays. The analyses for -the majority of compounds in Tables 5, 7 and 8 were conducted by standard gas chrom- atographic techniques. The data for benzene, toluene, methylene chloride in these tables are much less ac¬ curate because the measurements were conducted by de¬ termining only the total organic carbon concentration.

Example 6

The following Table 9 gives an initial comparison of literature values of- sorption capacities of activated charcoal for several organic compounds and sorption capacities from experimental data for the dimethyl di (hydrogenated tallow) a ine-bentonite form of the organoclay for these organic compounds. The data for charcoal was taken from EPA Report 600/8-80-23 and for the organoclay from data based on single experimental value per compound.

TABLE 9. - SORPTION CAPACITIES (mg/g)

Organic Compound Charcoal Organoclay

Benzene 0.1 18 Toluene . 25.0 6 Methylene Chloride • 1_ 2

Example 7

The superiority of the organoclay for sorption of organics was further investigated. The sorption of three forms of organoclay at various loading rates for 12 priority organics were compared with activated charcoal in laboratory experiments and these results are shown in the following Table 10.

^l _-_. . i. !_:_ __ fc_"___.__.T OMPI

Table 10.

P E R C E N T A G E O F S O R P T I O

Concen¬ Car¬ tration Clay Type Benzyl Ditallow Ethy 1 Hydroxy bon of Organic ug/1(ppb ) Clay Dose (mg/L) : 1130 660 1300 130 660 1300 130 660 1300 130 c ω π 1,000 Chloroform | 64 49 56 47 55 43 42 49 51 27

1,000 1,2 Dichloroethane | 46 36 50 48 49 42 34 29 36 40

1,000 1,1,1 Trichlorethane| 60 55 54 40 49 40 36 43 45 30 H 1,000 Trichloroethylene | 27 24 25 12 43 9 5 13 22 86

1,000 Tetrachlorethylene O 1 ⁸⁵ 46 74 47 51 60 11 39 60 92 a 700 2 Nitrophenols |84 87 99 96 ND 27 92 87 97 94 49 84 91 95 97 96 85 o

I

750 Pentachloroplienol | ND ND ND ND ND ND ND 94 92 ND 94

H 400 Dime hyphthalate | 85 ND ND 92 94 ND ND 70 ND ND 92

400 Lindane 99.7 93 ND ND 99.9 85 ND 98 ND 99.9 ND ND -

100 Arochlor 1254 40 29 90 88 95 94 88 77 98 90 98 '95 81 74 84 65 92 89 99.7

15 Ethyl Benzene | 29 16 22 13 24 71 8 16 — - ND = Not Detecte

- 41 -

Example 8

Trihalomethane removal has been- tested through chlorination of both synthetic organic water and natural water. The following Table 11 shows the re¬ sults of trihalomethane removal for a natural water.

Table 11.

"

Chlorinated

Lake Travis

Water CHCl^ CHCl?Br CHClBr ₂ CHBr-} THM

1 18 29 43 20 110

2 2__ 28 44 22 _. 114

Mean 19 28.5 43.5 21 112 ditallow* or ^■ gano- clay

Before 1 9.5 13 17 7.7 47.2

2 10 14 17 5.4 46.4

Mean 9.8 13.5 17 6.6 46.8

Removal % 48.4 52.6 60.9 68.6 58.2 benzyl organo¬ clay

Before 1 2.3 1.7 0.9 0.3 5.2

2 3.9 3.2 5.3 3.5 15.9

Mean 3.1 2.4 3.1 1.9 10.6

Removal % 83.7 91.6 92.9 90.9 90.5

Hydroxy ethyl organoclay

Before 1 2.6 7.3 15 12 36.9

2 2.9 6.0 12 13 33.9

Mean 2.8 6.6 13.5 12.5 35.4

Removal % 85.3 76.8 69.0 40.5 68.4

Terms have same meaning as in Table 10 .

SϋϋS _ _ _ u t. _._ -n-.-. i

_ OMPI °

- 42 -

Table 11. - cont ' d .

Chlorinated

Lake Travis

Water CHCl^ CHCl _? Br CHClBr? CHBr-3 THM ditallow organo¬ clay

After 1 15 18 25 9.4 67.4

2 13 18 26 12 69.0

Mean 14 18 25.5 10.7 68.2

Removal % 26.3 36.8 41.4 49.0 39.1 benzyl organo¬ clay

After 1 14 19 28 7.9 66.9

2 13 14 18 6 51.0

Mean 13.5 16.5 22 7.0 59.0

Removal % 28.9 42.1 49.4 66.7 47.3 hydroxy ethyl organoclay

After 1 16 21 32 14 83

2 17 25 35 16 93

Mean 16.5 23 33.5 15 88

Removal % 13.2 19.3 23.0 28.6 21.4

Terms have same meaning as in Table 10

su&ε ? •*•..*. ^p —"—- £ n t f k

Example 9

These are results of removal of organics before chlorination and post-chlorination sorption for three forms of organoclay based on post weight bases, concen¬ tration in ug/L. The earlier results from a study of trihalomethane removal from synthetic water by the ditallow form of organoclay are shown in following Table 12.

Table 12

CHCl^ CHCL _? Br CHCLBr _? CHBrj TTHM

Synthetic 111 73 45 5.3 234 water mg/L

Before Chlo¬ 74 77 76 77 75 rination, % removal

After chlo¬ 31 57 76 45 rination, % removal

Supplemented 167 85 42 3 . 2 297 Lake Travis Water, mg/L

Before chlo¬ 67 83 84 63 rination , % removal

Sϋ I i t U _ ___ Ss-.I_.ET

Example 10

In the following Tables 13 and 14, the removal efficiencies of the ditallow, benzyl and hydroxy ethyl organoclay are shown. Table 14 shows the sorbent THM removal efficiencies using synthetic water without bromide addition. ^" The data is based on the average of replicate experiments. The target level that the En¬ vironmental Protection Agency has set is 100 ppb. These experiments would indicate that the invention is close to the standard.

URE_

OMPI

Table 13.

CHCl- ₃ CHCl-pBr CHClBr CHBrς TTHM

Chlorinated synthetic water compo- sition, mg/L 183 30 217

Treatment Before Chlorination

Ditallow

Organoclay,

% Removal 90.0 83.7 91.3 89.0

Benzyl

Organoclay,

% Removal 86.3 79.0 55.1 84.7

Hydroxy Ethyl

Organoclay,

% Removal 71.9 33.3 7.7 65.3

Treatment After Chlorination

Ditallow

Organoclay,

% Removal 17.5 11.7 25.2 16.8

Benzyl

Organoclay,

% Removal 12.0 8.3 40.1 12.0

Hydroxy Ethyl

Organoclay,

% Removal 6.0 8.3 22.7 6.6

Terms have same meaning as in Table 10,

- 46 -

Table 14.

CHLOROFORM REDUCTION, %

Hydroxy

Sorbent Form Ditallow Benzyl Ethyl ** Organoclay Organoclay Organoclay

Treatment before chlorination 91.0 88.1 71.7

Treatment after chlorination 21.1 13.8 -3.6

Average of replicate experiments.

Terms have same meaning as in Table 10.

- r .

. -I 5 '.- £." _--!e...... ._ K_ _

" _B UREA OMPI

Example 11

_j ^\ Another concern of the Environmental Protection

Agency in the area of water treatment involves ground and surface water contamination by benzene, tetrachlor- 5 ethylene, trichloroethylene, carbon tetrachloride,

1, 1 , 1-trichloroethane, 1 ,2-dichloroethane, vinyl chlor¬ ide, methylene chloride, chlorinated benzenes and dichloroethylenes . These compounds can be successfully removed by using organoclay as an absorbent. The organ- 10 oclay can be applied in these applications in two ways One way is through the continuous flow through columns. Another is through batch addition to clarifiers. Figs. 14, 15, 16 and 17 illustrate experimental results from the column removal of polychlorinated biphenyls, 15 trichloroethylene, and dibromochloropropane by benzyl and ditallow forms of organoclay. These graphs show conclusive removal.

While the invention has been particulary set forth in terms of specific embodiments thereof, it 20 will be understood in view of the present disclosure, that numerous variations upon the invention will now be enabled to those skilled in the art, which varia¬ tions yet reside within the scope of the present teaching. Accordingly, the invention is to be broadly 25 construed, and limited only by the scope and spirit of ^" the claims now appended hereto.

_≥UL_ _S _ . t - _ ___ 3.-T _. EET