EVALUATION AND COSTS OF METHODS TO ELIMINATE ION EXCHANGE WASTE BRINE DISCHARGES FROM NITRATE TREATMENT PLANTS

Gerald A. Guter, Ph.D. Boyle Engineering Corporation

P.0.Box 670, Bakersf ield, CA 93302

INTRODUCTION

The use and disposal o f br ine regenerant i s a major cost and concern i n the operation o f an i o n exchange p lan t designed f o r removing n i t r a t e from a contaminated water supply. This paper reports on a study d i rected a t minimizing s a l t use and the waste br ine production. Methods o f t r e a t i n g the waste br ine t o render i t more e a s i l y disposable or t o render it reusable were studied.

Several methods were screened i n a prel iminary step i n the study. The b io log i ca l d e n i t r i f i c a t i o n o f the waste br ine was given the most a t ten t i on because i t appeared t o be the most readi ly adaptable t o br ine treatment and recyc l ing o f the waste. Experiments were conducted on t h i s and other process t o assess technical f e a s i b i l i t y . Costs were also developed f o r a system t o t r e a t and recycle the waste br ine from a one MGD i on exchange n i t r a t e treatment p lant .

This invest igat ion i s continuing w i th the operation o f a p i l o t p lan t t o study the combination ion exchange/brine d e n i t r i f i c a t i o n process. The r e s u l t s w i l l be reported a t e l a t e r date.

OBJECTIVE

The object ive of t h i s study was t o develop a method o f t rea t i ng the waste br ine from an i o n exchange n i t r a t e p lan t t o render i t o r port ions o f it reusable and reduce the dependence on waste discharge t o a l oca l sewer.

BACKGROUND

This Paper reports on a po r t i on o f an e f f o r t undertaken i n behalf o f the McFarland Mutual Water Company (McFMWCo.) f r o m March 1989 through October 1990 t o develop methods t o make s i g n i f i c a n t reductions i n the discharge o f the waste br ines from the two one MGD n i t r a t e Plants. I t was ant ic ipated t h a t s a l t cost reductions as wel l as reductions i n the use o f

This paper was presented a t the American Water Works ............................................................ Association 1991 Annual Conference held June 23 - 27, i n Phi ladelphia, Pa.

the loca l sewer f o r discharge o f waste s a l t s may be achieved by t h i s study.

The br ine from two one MGD plants i s cu r ren t l y being discharged t o the wastewater c o l l e c t i o n and treatment system operated by the C i t y o f HcFarland. A n i t r a t e p lan t was ins ta l l ed a t wel l No. 2 i n 1983 and one was i n s t a l l e d a t well No. 4 i n 1987. Both p lants have been i n operation since t h e i r i n s t a l l a t i o n and have been valuable t o the community by keeping the n i t i -ate content a t acceptably safe leve ls (below 45 mg NO3/L).

The two plants use the ion exchange process t o remove n i t r a t e from the pumped groulnd water. The process uses a bed o f ion exchange res in which can absorb n i t r a t e from water i n l im i ted amounts. To regenerate the bed, a concentrated br ine o f sodium chlor ide i s used t o remove the n i t r a t e from the resin. The nature o f the process i s t h a t an excess o f br ine must be used i n the regeneration step.

The s a l t usage i n 1988 and 1989 was approximately 900 tons f o r the two plants. This amount o f s a l t s eventual ly i s discharged t o the 120 acros o f i r r i g a t e d cotton which receives the t reated wastewater from the wastewater treatment p lant .

The methods studied under t h i s program t o reduce the br ine usage included a review and analysis o f several prospective processes t o t r e a t the waste and a review o f the operation o f the plants t o see i f they could operate w i t h less br ine. Also studied were pond evaporation and hauling t o a remote landf i 11.

Treatment o f waste br ine bv b io lon i ca l d e n i t r i f i c a t i o n and su l fa te removal el iminates v i r t u a l l y a l l br ine discharge and enables the recycl ing o f the br ine f o r f u r t h e r use. The n i t r a t e i s converted t o ni t rogen gas and the s u l f a t e i s removed as calcium su l fa te (gypsum) which i s land disposable. It i s estimated that the process inc lud ing the ion exchange plants can be operated wi th less chemical cost than actual chemical costs experienced by the MCMWCo. i n the base year 1989.

The study reported here i s a lportion o f the e f f o r t performed under a Professional Services Agreement Fo r Reclamation O f Waste Brine From N i t r a t e Removal Plants Pro ject dated March 11, 1989 (Outer, 1990) . This agreement was between the County o f Kern and Boyle Engineering Corporation. Funds fo r the pro ject were provided by the State o f Ca l i f o rn ia . The pro ject was administered by the Ca l i f o rn ia State Water Resources Control Board and the County o f Kern Community Development Program Department.

I

I

SCREENING OF CANDIDATE PROCESSES

The fol lowing processes t o t r e a t and recover the waste br ine were evaluated and screened. For d e t a i l s o f these evaluations and cost estimates, the reader i s re fer red t o the complete report (Guter, 1990) . A l i s t o f research papers on the various processes i s given i n the Bibl iography o f t h i s paper. Recently, C l i f f o r d (1990) has a lso reviewed some o f these processes.

The Processes which were evaluated included:

1 . 2 . 4 . 5 . 6 . 7 . 8. 9 . 10.

Crys ta l l i za t i on (Phase Transformation) Electrochemical Reduction Ca 1 c i nat i on Reverse Osmosis Use O f Waste Brine I n Water Softening. Extract ion Methods ( Inc lud ing Ion Exchange) Evaporation Ponds Use O f Potassium Chloride. Chemical Reduction o f N i t r a t e

These processes were rejected i n favor o f br ine d e n i t r i f i c a t i o n because o f e i t h e r one o r more o f the fo l lowing reasons:

o Lack o f technical f e a s i b i l i t y o I n a b i l i t y t o reduce s a l t discharge o r waste o High cost o Production o f undesirable by-products which could

L i t e ra tu re on the processes was reviewed (See Bibl iography) and when the Process and costs appeared promising, experimental t e s t s were performed.

Extract ion (treatment o f the br ine by weak base res ins) by ion exchange methods was an a t t r a c t i v e process bu t was rejected based on inabi 1 i t y t o separate n i t r a t e from chlor ide as e f f i c i e n t l y as the b io log i ca l d e n i t r i f i c a t i o n process.

contaminate the water supply.

BACKGROUND ON BIOLOGICAL DENITRIFICATION

A. INTRODUCTION TO BIOLOGICAL DENITRIFICATION

L i te ra tu re searches revealed a large amount o f informat ion on the use of b io log i ca l d e n i t r i f i c a t i o n f o r removal o f n i t r a t e from water (See Bibl iography). Several successful laboratory tes ts were performed dur ing t h i s study t o explore various aspects o f the Process. Because o f the amount of background information avai lab le and the success of

exploratory experiments, t h i s process was given the most a t tent ion under t h i s program.

The process i s being studied i n Europe and i n the U.S. for d i rec t treatment of water supplies t o remove n i t r a t e . Although research and p i l o t p lan t operations have been performed the d i r e c t treatment process has not been favored i n the U.S because o f the high cost and po ten t i a l contamination o f product water which may resu l t . I t also produces a t reated d e n i t r i f i e d water which requires f u r t h e r f i l t r a t i o n and pol ishing.

Recently, Van der Hoek has s,tudied a s i m i l a r process which overcomes many o f the above object ions by t r e a t i n g the Waste brines from ion exchange n i t r a t e p lants rather than d i r e c t d e n i t r i f i c a t i o n o f the water supply.

The b io log ica l d e n i t r i f i c a t i o n process makes use o f den i t r i f y i ng bacter ia which consume n i t r a t e and converts it t o nitrogen gas. The process; must take place i n an anoxic environment (oxygen must be excluded). The bacter ia feed on an organic material and are able t o obta in t h e i r oxygen supply from n i t r a t e sa l t s .

The process requires the addi t ion o f a carbon source such as methanol. Methanol i s general ly used as the preferred organic food mater ia l i n d e n i t r i f y i n g reactors because i t produces a sludge which i s more eas i l y removed by f i l t r a t i o n or s e t t l i n g . Other organic f u e l s such as ethanol, acet ic acid, g lycer ine and sugars have a lso been studied.

The nitrogen contained i n the n i t r a t e i on i s converted t o nitrogen gas which escapes from the reactor t o the atmosphere. A po r t i on o f the methanol i s converted t o an organic sludge which would be land disposable. Some o f the carbon from the methanol i s combined w i th the oxygen from the n i t r a t e t o form carbonate ion. The process then increases the a1 ka l i n i t y alf the wastewater during the d e n i t r i f i c a t i o n process.

Use of the d e n i t r i f i c a t i o n process t o t r e a t dr ink ing water d i r e c t l y requires introducing bacter ia d i r e c t l y i n t o the water supply. The process invest igated by Van der Hoek avoids t h i s problem by removing the n i t r a t e from the water by the ion exchange process and then d e n i t r i f i e s the waste br ine used i n the regeneration. Thus, the d i r e c t bac te r ia l contamination o f the water supply i s circumvented. Van der Hoek has shown t h a t bacter ia causing the d e n i t r i f i c a t i o n can grow and t h r i v e i n the concentrated waste br ines produced by the ion exchange process.

Whether the d e n i t r i f i c a t i o n occurs i n dr ink ing water or i n a concentrated waste brine, i t has been establ ished t h a t the

!

main b io log i ca l and The overa l l chemical by the equation

chemical cha rac te r i s t i cs are the same. balance o f the process can be expressed

5CH3OH + 6NO3' ---- > 3N2 + 4HC03- + COS= + BHpO.

(Some o f the carbon resu l t s i n sludge which i s not included i n the above equation.)

Approximately 0.43 pounds o f methanol are required t o convert one pound o f n i t r a t e t o ni t rogen gas.

B. RESEARCH AT WAGENINGEN I N THE NETHERLANDS

Experimental work on the appl icat ion o f the d e n i t r i f i c a t i o n o f waste br ines was f i r s t conducted a t Wageningen Univers i ty i n the Netherlands (Van der Hoek). A special process was devised t o continuously d e n i t r i f y a waste br ine from an ion exchanger by passing the waste through an upflow sludge blanket reactor (USBR). The br ine from t h i s reactor was c i rcu la ted through the i on exchanger and back through the USBR several times u n t i l the d e n i t r i f i c a t i o n was complete. This process tested by Van der Hoek was q u i t e successful. This work i s s t i l l being continued i n the Netherlands.

To operate t h i s process successful ly, the i on exchange p lan t and the USB reactor must be designed f o r continuous br ine production t o keep the b io log i ca l reactor i n operation.

D.

Appl icat ion o f the Wageningen process t o McFarland i s not appropriate because o f the t ime required f o r d e n i t r i f i c a t i o n t o occur and because o f the p o s s i b i l i t y o f introducing bacter ia l and organic contaminants i n t o the dr ink ing water. The process requires t h a t the ion exchange beds be sized t o al low a run time o f 9 t o 14 hours. The regeneration requires 3.5 t o 7 hours. (Shorter times are not s u f f i c i e n t for the d e n i t r i f i c a t i o n t o occur and longer times would cause the f l u id i zed bed operation o f the USB reactor t o possibly malfunction. 1 I n comparison, the McFarland p lants are designed f o r run times o f 4 t o 5 hours, and only 2 hours i s allowed f o r the regeneration when the p lan t i s i n continuous operation. Consequently, the use o f the USB reactor would not " f i t " the hydraul ics and t iming o f the McFarland p lants unless the Size o f the i on exchange beds were increased and the p lants were continuously operated.

The Wageningen process has po ten t i a l t o introduce organic contaminants including bacter ia i n t o the dr ink ing water because the resin, while undergoing regeneration f o r 3.5 t o 7 hours, i s exposed t o %he b i o l o g i c a l l y contaminated water, I t i s possible under these condi t ions t h a t bacter ia l growth

APPLICATION OF WAGENINGEN PROCESS TO MCFARLAMD

could be introduced i n t o the res in bed which would escape dis infect ion. Organic mater ia ls may also penetrate the resin pores. Transfer of these substances i n t o dr ink ing water could a lso cause the formation o f THM mater ia ls upon chlor inat ion o f the water supply. This i s a concern o f the Cal i forn ia State Department of: Health Services.

E. BATCH REACTOR TESTS

To make the b io log ica l d e n i t r i f i c a t i o n process more su i tab le f o r use i n the McFarland planlts the use o f a batch reactor was investigated during t h i s program. Both experimental work and other current research was reviewed. Actual ly, Van der Hoek (1987) used batch reactors i n i n i t i a l studies but d id not use t h i s type of reactor i n the combined ion exchange/biological p i l o t p lan t process described above.

A batch reactor would be used i n the fo l lowing way: Waste brine from one days operation o f a n i t r a t e p l a n t would be stored i n one o r more tanks. Methanol i s metered i n t o the tank wi th t race b io log i ca l nu t r i en ts where b io log i ca l d e n i t r i f i c a t i o n occurs. A f te r d e n i t r i f i c a t i o n i s comp 1 ete , the br ine i s f u r the r t reated f o r su l fa te removal, f i l t e r e d and disinfected. The treated br ine i s then stored f o r reuse.

Preliminary Tests With Batch Fleactors

I n August 1989, d e n i t r i f i c a t i o n t e s t s were conducted using d i f f e r e n t fuel materials. Tests were conducted w i th methanol, ethanol, sucrose, and a mixture o f corn meal and cereal. The t e s t s were conducted i n closed containers wi th mixtures of sodium n i t r a t e anld sodium chlor ide. The t o t a l TDS o f t h i s s a l t mixture was 4 ,080 mg/L. The i n i t i a l n i t r a t e concentrations were approximately 433 mg/L and chloride concentrations were 2100 mg/L. Kern r i v e r bottom sand was added t o each o f the above mixtures.

The containers were kept f o r over two weeks a t approximately 30 degrees C. w i th occasional ag i ta t ion. A f te r about 24 hours vigorous gas evolut ion was noted from the mixtures wi th accumulation o f sludge mater ia l a t the top o f each reactor. N i t r a t e tes ts were made frequent1 y. Conversion o f n i t r a t e t o n i t r i t e i n the mixtures was noted a f t e r a few days. Redoction i n n i t r a t e crnd n i t r i t e gradually occurred over a period o f about one week when gas evolut ion diminished. Addit ion o f f u e l and more n i t r a t e restar ted the gas evolut ion again w i th reduction i n n i t r a t e .

Batch and Continuous Reactor Tests

The batch tes ts were conducted i n 3 l i t e r reactors. The experiments were designad t o accomplish d e n i t r i f i c a t i o n i n a concentrated br ine so lut ion by s t a r t i n g d e n i t r i f i c a t i o n i n a

d i l u t e so lu t i on and gradually r a i s i n g the s a l t concentration. A concentrated mixture o f sodium n i t r a t e and chlor ide s a l t s wi th methanol was added t o the reactor containing water and sand. The reactors were covered wi th p l a s t i c wrap t o exclude a i r . N i t r a t e and n i t r i t e leve ls were f requent ly monitored using Hach t e s t k i t s . A few m l . o f so lu t i on from previous reactors was added t o help s t a r t the b io log ica l growth.

A stock so lu t i on o f sodium n i t r a t e and ch lor ide was used i n these t e s t s wi th a composition o f 32,860 mg/L n i t r a t e and 279,045 mg/L chlor ide. The addi t ion o f each 50 m l of t h i s so lut ion t o the 3 l i t e r reactor raised the ch lor ide by 5400 mg/L and n i t r a t e by 550 mg/L.

Test Number 1 and 2. were t r i a l t e s t s t o determine the procedures and condi t ions f o r the fo l lowing tes ts :

Test Number 3

F i f t y m l . o f the stock so lu t i on was added t o the reactor and 5 m l o f methanol. The reactor contained one inch o f sand and was f i l l e d wi th water and allowed t o stand a t room temperature. A f te r the fou r th day the n i t r a t e - n i t r i t e leve l began t o drop and n i t r i t e l eve l began t o r i s e . Gas bubbles were noted when the reactor was shaken t o s t i r the sand. On the eighth day the n i t r i t e l eve l reached a maximum o f 39 mg/L. On the n i n t h day the n i t r a t e - n i t r i t e leve l had decreased below detection. See Figure 1.

The reactor was then recharged w i th 50 m l o f the stock so lut ion and 3 m l of methanol. The n i t r i t e maximum was reached i n two days and a l l n i t r a t e and n i t r i t e had disappeared i n three days. This recharging process was repeated two more times w i th the resu l t s shown i n Figure 1. The average time required t o destroy the n i t r a t e was 3 . 5 days discounting the f i r s t induct ion period. Figure 1 shows tha t each subsequent charge required a longer period f o r the d e n i t r i f i c a t i o n t o occur as wel l as an increase i n the maximum n i t r i t e leve l which appears during the reaction. The f i n a l TDS o f the reactor so lu t i on was about 22,000 mg/L (or 2.2 percent br ine) .

Tests 4 Through 7

The above t e s t was repeated four more times w i th s i m i l a r resul ts . Each t e s t was inoculated w i th a few m l o f so lu t i on from the previous batch. Test 5 contained about a 50 x sand/water mixture. This t e s t s ta r ted w i t h a one day induction per iod and had an average cycle t ime o f less than three days.

Test Number 6 These so lut ions contained the fo l lowing composition o f major i ons :

Test 6 was s tar ted as a batch t e s t and converted t o a continuous flow system by adcling a pumped supply o f a 3 % brine a t twelve hour intervmls. I t was thought t h a t a regular feeding o f n i t r a t e arid methanol would increase the rate o f n i t r a t e destruction. This t e s t was also equipped f o r gas measuring. D e n i t r i f i c a t i o n i n t h i s system stopped a f t e r about one week o f operat,ion.

Test Number 7

This t e s t was conducted i n ai manner s i m i l a r t o the above batch tes ts but the batch contained a 6 % br ine so lut ion. No d e n i t r i f i c a t i o n occurred.

The above tes ts ind icate t h a t

b io log ica l d e n i t r i f i c a t i o n i s very e f f e c t i v e i n destroying the n i t r a t e from a s a l t solut ion.

An induction period o f from one t o four days was

A f t e r the bacter ia l act ion i s establ ished the n i t r a t e i s destroyed i n about three days.

D e n i t r i f i c a t i o n i s slower i n high br ine concentration.

A s i x percent br ine so lut ion would not d e n i t r i f y w i t h the bacter ia l cu l tu re used i n t,hese experiments.

More n i t r i t e i s produced at, the higher br ine

The flow through system was unsuccessful.

observed.

concentrations.

Fxoerimental Tests With Ten Petrcent Brines

Work i n Orange County (Davidson, 1990) demonstrated t h a t den i t r i f i ca t i on can occur i n approximately ten percent brines. D r . Davidson k ind l y pirovided samples o f h i s cu l tu re f o r test ing under t h i s program.

Den i t r i f i ca t i on i n ten percent. br ines would be desirable f o r use i n McFarland because smaller amounts o f l i q u i d br ine need be handled wi th smaller storage tanks (lower cap i ta l costs).

Solutions containing sodium chlor ide, sodium n i t r a t e , sodium bicarbonate and trace n u t r i e n t s a l t s were prepared having t o t a l so l ids o f 9.65 percent f o r test ing.

Sodium Chloride 80 gm/L 1368 meq/L Sodium N i t r a t e 5 5 9 Sodium Bicarb. 10 119

Trace amounts of n u t r i e n t mater ia ls including ammonium, phosphate, calcium, magnesium and i r o n s a l t s were also added.

Each o f three batch reactors were prepared f o r d e n i t r i f i c a t i o n by using three l i t e r s o f the above so lu t i on and one o f the fo l lowing fue ls :

Methanol 6 .48 ml/L (5.13 gm/L) Sodium Acetate ( t r i hyd ra te ) 124 gm/L G1 ycerol 59.46 ml/L ( 7 5 gm/L)

Each batch reactor contained 176 meq o f n i t r a t e which would be converted t o 176 meq o f n i t rogen gas i f d e n i t r i f i c a t i o n occurred. This amount of n i t rogen would have a volume a t STP o f . 1 7 6 x 11.4 = 1.9712 l i t e r s .

The reactor containing the methanol d i d no t generate gas nor was n i t r i t e detected i n the so lu t i on a f t e r several days.

The reactor containing acetate s ta r ted gas evolut ion w i th in one day as d i d the glycerol reactor. Each reactor so lut ion tested p o s i t i v e f o r n i t r i t e ion.

A reactor was s tar ted w i t h sodium acetate and set up t o measure the amount o f gas evolved. Figure 2 shows the ra te o f gas evolut ion which was measured. A f te r gas evolut ion stopped, one l i t e r of the reactor was replaced wi th one l i t e r o f the above br ine so lu t i on and an addi t ional 10 grams o f sodium n i t r a t e ( f o r a t o t a l o f 15 grams) were added w i th 60 m l . of glycerol . Figure 2 shows the r a t e o f gas evolut ion and also shows the bacter ia read i l y adapted from sodium acetate t o g lycero l , however, the d e n i t r i f i c a t i o n rate i s much slower (.38 times as f a s t ) .

These t e s t s ind icate the po ten t i a l f o r using d e n i t r i f i c a t i o n i n a h igh ly concentrated br ine. I f t h i s process modif icat ion were developed fu r the r , smaller tankage and lower cap i ta l cost would lower cap i ta l equipment costs.

University O f Houston Research

The Universi ty o f Houston has a research p ro jec t now underway which i s producing wary s i g n i f i c a n t r e s u l t s i n the f i e l d of b io log ica l d e n i t r i f i c a t i o n o f waste brines. ( C l i f f o r d and Liu, 1 9 9 0 . ) Their work w i l l be published soon. They have been conducting d e n i t r i f i c a t i o n experiments f o r over three years and have been successful i n t r e a t i n g and recycl ing the waste br ine from an ion exchange COlUmn.

F. SLUDGE PRODUCTION

One o f the very a t t r a c t i v e features o f the b io log i ca l d e n i t r i f i c a t i o n process i s tho small amount o f sludge which would be produced. From research conducted by Van der Hoek, the amount of sludge produced by the d e n i t r i f i c a t i o n process can be estimated t o be about 10.3 grams per gram o f ni t rogen consumed. The amount o f n i t rogen removed from the t reated water i s approximately 10 mg NOS-N/L. (o r 83.4 pounds per m i l l i o n gal lons) (o r 53.376 pounds per .64 mg, which our basis o f cost estimates f o r t h i s process i n McFarland). The sludge production would be approximately s ixteen pounds per day. This sludge i s the biomass produced from the react ion and i s d i r e c t l y disposable e i t h e r t o the sewer or could used as f e r t i l i z e r .

COST OF A BRINE TREATMENT SYSTEM USING BIOLOGICAL DENITRIFICATIOM OF WASTE BRINE

A. BRIEF SUMMARY OF RECOMMENDED PROCESS

1. Preliminary design and cost estimates f o r a f u l l scale br ine treatment process were developed as a r e s u l t of t h i s study. The b io log ica l d e n i t r i f i c a t i o n o f waste br ine was selected as the key step i n the process. The process also includes removal o f s u l f a t e from the br ine and replacement wi th chlor ide. The process el iminates the need t o discharge lairge quan t i t i es o f s a l t s t o the domestic sewer system tis i s now the pract ice. The process produces approximately 16 pounds per day o f an organic sludge which i s eas i l y disposed.

2. A process f low diagram, Figure 3, was developed only as a basis f o r the estimation o f cap i ta l and operating costs. This diagram i s thought t o be representative o f a t yp i ca l one which can be u l t ima te l y developed. Modif icat ions o f the process are l i k e l y as p i l o t p l a n t operation i s required p r i o r t o f i n a l i z a t i o n o f the process.

3.

4.

5.

6 .

7.

B.

Capital costs range between $130,000 and $285,000. The lower f i g u r e i s f o r a p l a n t using only the b io log i ca l d e n i t r i f i c a t i o n step. The higher cost i s f o r a p lant using both d e n i t r i f i c a t i o n and s u l f a t e replacement. These costs do not include the ion exchange p lan t equipment which i s now operating i n McFarland.

Operating costs vary between $40 and $118 per day depending on various process options evaluated. These costs include a l l chemicals t o operate both the ion exchange Plant and those required f o r the br ine recyc l ing Process. These costs can be compared t o the average d a i l y s a l t cost o f $67 which McFMWCo paid i n 1988.

The use of a n i t r a t e se lect ive r e s i n i n the n i t r a t e p l a n t instead o f the current s u l f a t e se lect ive res in (Type 1 ) was evaluated f o r i t s cost advantage when used i n conjunction w i t h the above b r ine treatment process. A waste br ine i s produced which r e s u l t s i n a lower operating cost because it contains less waste su l fa te.

The amount o f waste br ine el iminated from discharge, except f o r process i n e f f i c i e n c i e s and r e s i n washing, var ies between a nominal 100 percent e l iminat ion t o 25 percent depending on the process option.

A cost t o bene f i t r a t i o analysis i s presented f o r the various process options. The n i t r a t e se lect ive res in gives the maximum s a l t waste reduction per d o l l a r o f operating cost.

N i t r a t e se lect ive resins are no t avai lab le on the U.S market bu t are cu r ren t l y being evaluated by the federal and s ta te governments f o r use i n the U.S.

NEED FOR PILOT PLANT OF BIOLOGICAL BRINE TREATMENT

Although t h i s process i s being recommended f o r the McFarland appl icat ion f u r t h e r t e s t i n g and studies are needed before a f u l l scale demonstration p l a n t can be b u i l t and operated. Both laboratory and p i l o t scale t e s t i n g are required. Items t o be addressed i n such studies are:

1. Type o f b io log i ca l reactor design best su i ted f o r McFar 1 and.

2. Time required t o complete the d e n i t r i f i c a t i o n i n a batch reactor. The proposed Prel iminary design given i n t h i s repor t assumes br ine treatment i s completed i n a dai 1 y batch.

3. Removal of su l fa te from the waste br ine, replacement w i th ch lor ide and disposal of calcium s u l f a t e (gypsum).

4 .

5 .

6.

7 .

8 .

9.

10

C .

Potent ia l contamination o f the water supply by bacter ia and dissolved organics.

Potent ia l contamination of the water supply w i th trihalomethane (THM) forming organics.

Effects o f temperature on d e n i t r i f i c a t i o n rates.

Impact of i d l e p lan t time on the process.

Impact of the process on ,the operation o f the n i t r a t e plants.

Use of n i t r a t e se lect ive resins i n the process t o save operating costs.

Acceptance o f process by the State Department o f Health Services because t h i s agency regulates the operation o f the McFarland p lants and must permit any operational and process changes. Chief concerns are ef fect iveness o f d is in fect ion o f reusable br ine and po ten t i a l impact on trihalomethane or other d i ss in fec t i on by products formation.

BASIS OF PRELIMINARY DESIGIV AND COST OF BRINE RECOVERY/RECYCLING SYSTEM IFOR MCFARLAND

Although the above items are required f o r study p r i o r t o the construction and operation of a br ine recovery p lan t an estimate of the cost o f a p lan t and i t s operation are included i n t h i s report . This prel iminary design i s thought t o be t yp i ca l o f one which w i l l be adopted a f t e r p i l o t test ing i s completed. Because these costs are dependent on a number o f variables ce r ta in assumptions are made t o f i x the costs for a t yp i ca l p lant. Thiese assumptions include the fol lowing.

1. The process i s as described below.

2 . The da i l y t reated f low froin the i on exchange p lan t w i l l be 50 percent o f i t s maximum or peak design f low capacity .

3 . The raw water composition i s t y p i c a l o f wel l 4 which approximates

N i t r a t e = 64 mg N03/1 Su 1 f a t e = 155 mg/l Chloride = 70 mg/l Bicarbonate = 70 m g / l

4 .

5 .

6 .

7 .

8 .

The water w i l l be t reated t o 20 mg N03/1. This w i l l a l low a blended (e 30 mg N03/1) water production o f . 6 4 MGD or a blended ( Q 40 mg N03/1) water production o f .69 MGD per wel l s i t e .

The concentration o f br ine used f o r regeneration w i 11 be approximately 3 percent as sodium chlor ide.

The res in used i n the ion exchange process i s the same as i s now i n use which i s a Type 1 strong base anion exchange resin. (The use o f a n i t r a t e se lect ive r e s i n i n the ion exchange vessels i n conjunction w i th the br ine treatment process i s a lso evaluated.)

The time required for the d e n i t r i f i c a t i o n and b r ine treatment w i l l be less than 24 hours t o al low a one day supply o f br ine t o be t reated and reclaimed w i t h i n t h a t period. Shorter d e n i t r i f i c a t i o n times would a1 low smaller tankage and more frequent processing o f br ine batches.

The approximate composition o f the untreated waste br ine w i l l be:

Ch 1 o r i de Bicarbonate 12

254 Sul fa te N i t r a t e 48

165 meq/l

This br ine w i l l be t reated t o convert the bulk o f the n i t r a t e , su l fa te and bicarbonate by various process steps i n t o chloride. This br ine composition i s t y p i c a l o f the br ine obtained i n McFarland. I t i s noted t h a t the su l fa te i s the most abundant mater ia l . The high s u l f a t e i n the raw wel l water and the use o f a Type 1 r e s i n i n the i on exchange p lan t cause the su l fa te t o be higher than the other ions. For t h i s reason, consideration was given t o using a n i t r a t e se lect ive res in i n the ion exchange p lan t t o reduce costs associated wi th the waste s u l f a t e treatment.

9. The service batch fo r the ion exchange p lan t i s 153,000 gallons. The 3 percent b r i ne batch i s 2386 gallons. The regeneration frequency i s 3.27 times per day. The design regeneration frequency i s assumed t o be 4 times per day.

10. Only the waste br ine w i l l be t reated. No recyc l ing o f r i nse water i s included.

Both cap i ta l and Operating chemical costs are developed based on the above assumptions.

D. DESCRIPTION OF PROCESS

The basic process for br ine relcovery and recycl ing i s shown i n Figure 3. This pa r t i cu la r process f low i s one o f several which can be used and i s proposed only f o r the purpose o f estimating costs. The process i s based on using b io log i ca l d e n i t r i f i c a t i o n f o r destruct ion o f the n i t r a t e i on and p rec ip i t a t i on o f calcium su l fa te by addi t ion o f calcium chlor ide for removal o f the su l fa te i on and i t s replacement by chloride. The stream compositions and d a i l y quan t i t i es are given i n Table 1.

The waste br ine from the i on exchange p lan t i s produced i n two sequential batches instead of the one s ing le batch as i s now obtained i n the present method o f operation. Stream S10 i s the f i r s t br ine batch t o be obtained and i t contains the bulk o f the su l fa te; stream S20 contains the bulk o f the n i t r a t e . Although some su l fa te remains i n S20 it does not i n te r fe re i n subsequent regenerations. The small amount of n i t r a t e which f lows through stream S l O i s not removed from the brine, however, it can bo to lerated i n the recovered brine.

Stream SI0 i s mixed wi th calcium chlor ide i n a batch tank T11. The prec ip i ta ted calcium su l fa te i s fed d i r e c t l y t o a f i l t e r press F1 from which the calcium s u l f a t e so l i ds are extracted as approximately 50 percent so l ids. Rinsing o f the sodium chlor ide from the so l i ds can be done w i t h i n the f i l t e r press. Stream S I 2 contains the sodium chlor ide product which i s sent t o the recovered br ine storage tank T22

Stream 520 i s sent t o storage tank T20. Once each day the contents o f t h i s tank i s pumped i n t o the b io log i ca l denitrification/sequential batch reactor (SBR) T21. Methanol i s metered i n t o the reactor t o serve as the fue l f o r the d e n i t r i f i c a t i o n which occurs i n approximately 20 hours. Stream S21 i s the d e n i t r i f i e d br ine and i s pumped i n t o the t reated br ine storage tank where i t blends w i t h the stream S13 and where hydrochloric acid i s added t o neutral ize the bicarbonate.

E. CAPITAL COSTS

The cap i ta l cost estimate f o r 'the complete p l a n t are l i s t e d and t o t a l l e d i n Table 2. I t i s noted t h a t the f i l t e r press F1 i s the s ing le i tem of highest cost. Further invest igat ions on the p r e c i p i t a t i o n and handling o f the calcium su l fa te could show t h a t a f i l t e r press can be replaced by a less expensive handling method or procedure.

There are also other options avai lable which can reduce the capi ta l cost o f equipment for t h i s process. These options

were studied t o examine the s e n s i t i v i t y o f the cap i ta l and operating costs t o type o f r e s i n used i n the ion exchange p lant and the cost o f t r e a t i n g only one o f the two separated streams. These options w i l l be re fer red t o f requent ly and are l i s t e d as fo l lows:

DescriDtion o f ODtion O D t i on

DN1 D e n i t r i f i c a t i o n Only using Type 1 res in i n ion exchange p lant .

DN2 D e n i t r i f i c a t i o n Only using a n i t r a t e se lect ive res in i n the ion exchange p lant .

DNSRl D e n i t r i f i c a t i o n plus s u l f a t e replacement using Type 1 r e s i n i n i on exchange p lant .

DNSR2 D e n i t r i f i c a t i o n plus su l fa te replacement using n i t r a t e se lect ive res in i n ion exchange p lant .

SRl No d e n i t r i f i c a t i o n but replace only the su l fa te from an ion exchange p l a n t using Type 1 res in .

No d e n i t r i f i c a t i o n but replace only the su l fa te from an ion exchange p lan t using n i t r a t e se lect ive resin.

Option DN1 would process only the S20 stream i n Figure 3 while the S10 stream i s dumped t o waste. Option DN2 would do l ikewise but would t r e a t the br ine from an ion exchange p lant using a n i t r a t e se lect ive resin. The McFarland p lants are current ly using a Type 1 resin. For these two options cap i ta l equipment f o r the s u l f a t e stream processing can be el iminated t o reduce the p lan t costs. The l i s t o f equipment and cost estimates f o r these two options, DNl and DN2, i s given i n Table 3. Because o f the di f ferences i n the res ins d i f f e r e n t amounts o f br ine w i l l be wasted and operating costs w i l l vary considerably. See below.

Options DNSRl and DNSR2 w i l l t r e a t both S10 and S20 streams as shown i n Figure 3 and d i f f e r only i n type o f r e s i n used i n the ion exchange Plant. Differences i n resins do not a l t e r the cap i ta l cost of the equipment l i s t e d i n Table 2. Replacement o f the type 1 res in w i th a n i t r a t e se lec t i ve res in would be an addi t ional cost. A s these resins are not yet avai lab le i n the U.S no estimate of p r i c e f o r them can be made a t t h i s time.

For completeness, consideration o f t r e a t i n g only the s i 0 stream was also made i n options SR1 and SR2. These require discharging the S20 stream t o waste. These options are characterized by r e l a t i v e l y higher chemical cost and high

SR2

waste discharges. Separate capital costs are not included in the cost tables because these options do not treat the nitrate in the waste brine.

F. FINANCIAL IMPACT ON McFARLAND

The financial impact on the McFMWCo. can be estimated on the basis of an 8 percent construction loan amortized over a 20 year period. Using the cost of $ 130,000 as Capital expenditure, the capital recovlery cost would be $13,241 per year or $2 .20 per person in McFarland per year. For the capital recovery cost of $ 285,000, an annual capital recovery cost of $ 29,027 per year is required or $4.83 per person per year.

The above costs can be compared to what is currently being paid for water by the customers of McMWCo which is estimated to be approximately $350 per family per year. The lowest rate charged by McFMWCo is $12.25 per 1000 cubic feet (or $1.64 per 1000 gallons).

G. ESTIMATES OF CHEMICAL COSTS The major component of operating costs of the brine recovery process is the amount of chemicals required. The required chemicals are:

Methanol Hydrochloric Acid Calcium Chloride Bi onutri ents

Methanol is used as the energy source to convert nitrate- nitrogen into nitrogen gas by bacterial action in an anoxic environment. Other products produced in this reaction are carbon dioxide which appears; in the brine solution as bicarbonate or carbonate ion and an organic sludge. Both of these materials are disposable materials.

Hydrochloric acid reacts to form carbon dioxide from the bicarbonate ions found in the waste brine and formed from the denitrification. All bicarbonate ions are converted to chloride ions in this process.

Calcium chloride i s a salt obt,ainable in anhydrous form and will form a precipitate of calcium sulfate when added to the waste brine. Familiar forms of calcium sulfate are gypsum, used as a soil amendment, and iplaster of Paris. These forms differ in the water contents and crystalline forms. The calcium sulfate obtained in this process would be most suitable for land disposal.

Bionutrients are trace amounts of materials required for good bacterial growth includiing phosphate, potassium, iron and magnesium. These maternals are used only in trace

amounts and are likely to already be present in the waste brine.

The chemical quantities and costs associated with the above process options are given in Table 4 and Table 5. Included is a comparison to the current operation of no brine treatment. The costs listed in these Tables for the various options include all chemical costs required to operate the ion exchange plant and the brine recovery process.

The daily amounts and kinds of chemicals required for the various options are shown in Table 4. The amount of NaCl required for each process represents an amount of salt which must be wasted because the excess sodium ion must be removed from the process. The total amount of chemicals required varies from 634 pounds for the DN2 option to 1833 pounds for the SR1 option. These values can be compared to the 1826 pounds of salt currently used.

Table 5 lists the daily costs o f chemicals for the various options. The lowest cost is f o r option DN2 being only $3 more than the current cost of salt. The highest chemical cost i s for option DNSRI which is about 3.5 times greater than the current cost. However, the latter option eliminates a nominal 100 percent of the salt waste from the process.

Although cost is a major consideration in choosing the option for application, the amount of salt discharge i s the major environmental concern. A graphical representation of the data from Tables 4 and 5 is given in Figures 4 and 5 to represent the cost/environmental tradeoffs.

Figure 4 graphically compares the daily chemical cost with the percent of the brine which is wasted for the various options. The current plant operation i s represented by the two bars on the left of each figure labeled "PRESENT". In this case 100 percent of the plant waste salts are discharged. The graph shows that options DNSRI and DNSR2 give a nominally zero salt discharge, but at much higher cost than the current operation. The DN2 option shows the next most desirable environmental option at only a slightly higher operating cost than present.

Figure 5 graphically represents the benefit to cost ratio of each option. The chart makes a comparison of the relative salt waste reduction Per dollar of chemicals consumed in the process to the amount of salt waste discharged. The order Of decreasing cost efficiency 1s DN2 > DNSR2 > DN1 > DNSRl > SR1 SR2.

This analysis shows the superiority of the nitrate selective resins in the ion exchange vessels when used in conjunction with this brine treatment process. Nitrate selective resins

are not current ly avai lable on the U.S market. The r e s i n evaluated above was developed under a previous EPA grant to the McFarland Mutual Water Company. The use o f the res in i n dr inking water systems i s current ly under review by the U.S government and would posdii b l y be avai lab le when the construction o f a waste br ine recovery system i s ready for operation.

CONCLUSIONS

1. Prel iminary designs and cost estimates f o r a f u l l scale br ine treatment process were developed. The b io log i ca l d e n i t r i f i c a t i o n o f waste br ine was selected as one o f the steps. The process a lso includes removal of su l fa te from the br ine and replacement w i th chlor ide. Products o f the process are ni t rogen gas, gypsum, organic sludge, and recyclable br ine. Modif icat ions o f the process are l i k e l y as p i l o t p lan t operation i s required p r i o r t o f i n a l i z a t i o n o f process. Ca l i f o rn ia State Health Department approval must be obtained before the t reated briine can be reused i n the water treatment process.

2. I t i s estimated t h a t the amount o f waste br ine el iminated from discharge by using the above process, except f o r res in washing and process i ne f f i c i enc ies , var ies between a nominal 100 percent t o 25 percent depending on the process option.

3. Capital cost estimates f o r construct ing a br ine reclamation p lant a t each ion exchange p lan t s i t e range between $130,000 and $285,000 per s i t e , again depending on the option chosen. The lower f i g u r e i s f o r a p lan t using only the b io log ica l d e n i t r i f i c a t i o n step. The second cost i s f o r a p lan t using both d e n i t r i f i c a t i o n and su l fa te replacement. These costs do not include the ion exchange p lant equipment. Lower costs would l i k e l y be real ized by use o f a centra l p lan t f o r br ine processing.

4. Chemical cost estimates per p l a n t t o t r e a t waste from one n i t r a t e p lan t vary between $40 and $118 per day depending on various process options evaluated. These costs include a l l chemicals t o operate both the ion exchange p lan t and those required f o r the br ine recycl ing process. These costs are compared t o $ 67 per day f o r the average d a i l y s a l t cost f o r the 1988 base year ( the calendar year p r i o r t o i n i t i a t i n g t h i s study). Through br ine conservation, treatment and recycl ing, lower operating costs ( inc lud ing both the ion exchange process and br ine treatment) as wel l as less br ine disposal can be rea l ized when compared t o the base year operation. P i l o t Plant operation o f the

Process i s recommended t o obta in more exact 0 and M costs.

5. An invest igat ion o f the operation o f the n i t r a t e p lants i n McFarland was performed ea r l y i n t h i s study. The operation o f the p lants was readjusted f o r reduced waste br ine production ea r l y i n 1989 and continuously monitored for reduced br ine operation throughout the year. Again using 1988 as a base comparison year, the p lan t readjustments resul ted i n a 47 percent br ine savings i n 1989. A s was indicated above, t h i s savings resul ted i n an annual s a l t cost savings o f $ 16,760 f o r t he McFMWCo based on actual water production i n 1989.

BIBLIOGRAPHY AND REFERENCES

GENERAL REFERENCES

Adams, Warren H. ; Fowler, E r i c 0.; and Christenson, C.W.: "Treating Radioactive N i t r i c Acid Wastes" I n d u s t r i a l and Engineering Chemistry Vol. 52 No. 1 January 1960.

Paper on use of paraformaldehyde as a reducing agent. By-products are formic ac id and ni t rogen dioxide.

C1 i f f o r d , D. " Ion Exchange and Inorganic Adsorption" i n Water Q u a l i t y And Treatment. AWWA, Fourth Edi t ion, McGraw- H i l l , 1990.

Grinstead, R.R.; Davis, J.C.; Snider, S.W.: "Recovery o f Sal ts from Saline Water Via Solvent Ext ract ion (Final Report)". U.S. Dept o f I n t e r i o r R and D Progress Report No. 406.

Reports on the s e l e c t i v i t y o f Alkylammonium Ions i n ex t rac t i on o f inorganic Anions.

Gunderloy, Frank C. , J r . ; Fujikawa, C l i f f Y.; Dayan, V ic tor , H. and Gird S.: "D i l u te Solut ion Reactions o f The N i t r a t e Ion as Applied To Water Reclamation". U.S Dept. o f I n t e r i o r , FWPCA, Report No. TWRC-1, October 1968.

Reports on chemistry o f n i t r a t e i on i n d i l u t e so lut ions f o r the purpose of d i r e c t chemical removal o f n i t r a t e i on from dr ink ing water. Several chemical reduction reactions are discussed.

Gunderloy, Frank C. , Jr . ; Wagner, Ross I.; Dayan, V ic tor , H.: "Development of a Chemical D e n i t r i f i c a t i o n Process".

41 8

EPA report for Program #17010 EEX, Contract $14-12-548, October 1970.

Reports on the denitrification of nitrate in drinking water using chemical reduction by ferrous ion.

Guter, G.A. "Reclamation Of Waste Brine From Nitrate Removal Plants" Final Report To County Of Kern, Community Development Program Department, October, 1990

Healy, T.V.: "The Reaction O f Nitric Acid With Formaldehyde And With Formic Acid And Its Amlication To The Rc Nitric Acid From Mixtures". J. Appl. Chem, 8 Septem

H.E.W.: U.S.Dept of Health EIducation and Welfare, Waste Treatment Research, ,AWTR-14, Environmenta Series. April 1965.

nova1 Of er 1958.

Advanced Health

Reports on calcination process to convert nitrate salts into nitric acid.

Lockridge, J.E.: Doctoral Dissertation: "New Selective Ion Exchange Resins For Nitrate Removal From Contaminated Drinking Water And Studies On Analytical Anion Exchange Chromatography". Iowa State University, Ames, Iowa, 1989.

Reports on use of using a mixed anion/cation bed for removing nitrate and calcium ions from water.

Prunac, A.D.L; Bauer, D.M.: European Patent 86309491.8, 1987.

Patent on use of sulfate brines to regenerate water softening cation exchangers. Cited by Lockridge

Sada, E; Ohno, T.; and Kito, S.: "Salt Effect On Vapor- Liquid Equi 1 ibria For Acetone Water System". Journal of Chemical Engineering of Japan. Vol 5 No.3, 1972.

Vapor-liquid equilibrium data of acetone systems saturated with sodium chloride and nitrate are reported.

Sidgwick, N.V.: "The Organic Chemistry of Nitrogen". Oxford at the Clarendon Press, 1937.

Reviews reactions o f alcohols with nitric acid forming esters and their properties.

REFERENCES ON BIOLOGICAL DENXTRIFICATION

Clifford, D. and Liu, X . : Private communication April, 1990

Dahab, M.F. and Lee, Y.W.: "Nitrate Removal From Water Supplies Using Biological Denitrification", Journal WPCF, Volume 60 No.9 page 1670-1674.

Davidson, Mike: Private communication. June, 1990

Gauntlet, R.B. and Craft,D.G.: "Biological Removal of Nitrate from River Water. Dept of the Environment Treatment Division Water Research Centre, Report No. TR 98. May 1979.

Meyer, G.A.: "Use of Endogenous or Sequestered Carbon for Denitrification in a Sequencing Batch Reactor Activated Sludge System" M . S . Thesis, UC Davis. 1988

Van der Hoek, J . P. : "Combined Ion Exchange/Biological Denitrification For Nitrate Removal From Ground Water", Doctoral Thesis, Wageningen Agricultural University, Wageningen, The Netherlands. 1988.

The following papers are included as chapters in the above thesis.

Van der Hoek, J.P.; Latour, J.M. and Klapwijk, A,: "Denitrification With Methanol In The Presence of High Salt Concentrations and at High PH Levels" Appl. Microbiol Biotechnol (1987) 27:199-205.

Van der Hoek, J.P.; Latour, J.M.: and Klapwijk, A.: "Effect of Hydraulic Residence Time On Microbial Sulfide Production In An Upflow Sludge Blanket Denitrification Reactor Fed With Met h an 0 1 *'

Van der Hoek, J.P.; Latour, J.M.; and Klapwijk, A.: "Nitrate Removal From Ground Water - Use of a Selective Resin and a low Concentrated Regenerant.

Van der Hoek, J.P.; Verhaijen, J.; P im, 1.M.Vis and Klapwijk, A . : "D is in fect ion (of Anion Exchange Resins i n the Combined Ion Exchange/Biological D e n i t r i f i c a t i o n Process. Part I . Effect on Water Qua l i t y " and " ... Part 11. E f f e c t on Resin Capacity".

Van der Hoek, J.P. and Klapwijk, A.: "N i t ra te Removal From Ground Water", Water Research Vol. 21 No.8 pp 989-997, 1987.

Sol t , George S.: and Klapwijk. U . S Patent 4,671,879. June 9, 1987.

I f

IN 0 z z 4

I - O z CL 0 t- u U W e I u c U

n

m

0

3000

2500

r -

FIGURE 2

. . .

0 1 2 3 4 5 6 7 8 9 1 0 1 1 1 2 1 3 1 4 1 5 1 6

DAY

GAS PRODUCTION IN 107: BRINE

TO ION EXCHANGE PIAM s22 v22

n

BRINE RECOVERY PROCESS DENITRIFICATION PLUS SULFATE REPLACEMENT

FIGURE 3

Y

P

i? v)

' I W

IL: z m

c) z 4

100

50

0 PRESENT DNl ON2 D N B l DNSR2 SR1 sf72

ON-OOITRFT

SR-REUOW WAX 1-m 1 RESN

2-" REON PERCENT BRINE WASTED COUPARED TO CHMCAL COSTS OF VARIOUS OpnoNs

FIGURE 4

150

100

50

0

TABU 1. PROCESS STREAP! ANION COMPOSITIONS AND DAILY FLOWS milli-r Mer Stream/ Flow Gallons Of Daily

Designation Flow Nitrate sulfate chloride Bic ---- s10 7 459 2 12 VlO 4330

811 7 0 461 12 v11 4330

112 v12

813 V13

s20 v2 0

S2l Vt 1

s22 v2 2

4330

4330

4330

8660

1127 pounds of Calcium Sulfate ) with 135 gallons water. 50% solids]

7 0 461 12

87 51 330 12

0 51 330 99

4 26 450 0

TABLE 2 W I T A L COST FOR DENITRIFICATION AND SULFATE REMOVAL

FST. COST AmL. ESCRIPT'ION

T10 Tank for Calcium Caloride Storage 12_"7'H fiberglar, 5600 gal. p8netration and fittings

T U Waste wine Storage and Mixing lZ'x7'H fiberglass 5600 gal Penetration and fittings

T Z O

T21

Waste Brine Storage 12*x7'H fhrglaas 5600 gal Puletration urd fittings

6720 1000

6720 1000

6720 1000

Denitrification Batch Reactor 12*x7 'B f iberglaas 5600 pal 6720 Puletrations and fittings 1000

T2 2 Treeted Brine Storage 12*Dxl6'H 12500 gal 15000 Penetrations and fittings 1000

10 two gpm units 12000

6*Dx5'H polypro double wall. 2000 Ejector and pump 1200

uv Ultra Violet Dissinfection Unit

ACID Hydrochloric Acid Storage ,Feed Sys.

P8netratioru urd fittings 600

IIEOH Hethanol Storage end Feed Systm D m handling rquipaent Metering pump ?ire safety equipment

5000 1600 2000

TABLE 2 CAPITAL COST ITEMS FOR DENITRIFICATION AND S W A T E RMOVAL

(Continued)

Rrmps

Controls Control System

piping Hiscellaneous, piping, valves fittings

Foundatiorm

Electrical

Intsrface Interface to existing plant

Seven 1/2 to 1 Xp hansfer m p s

Hardware, software, programming

SIIBTOTAL W I C C0MPO"l'S

F1 -flow Filter Press For dewatering Calcium sulfate

Total Engineering Capital

Contingencies @ 20%

Grand Total

3500

10000

15000

25000

12000

6000

142780

75000

217780 22000 42000

281780

TABLE 3 WITAL COST 1- FOR IENITRIFICATION ONLY

ITM - T20

T2 1

n 2

W

ACID

mon

Pumps

Controls

Piping

?oundations

Electrical

Interf aCo

EeseLxEus?E Waste Brino Storago l2'x7'S fiborqlams 5600 Pa l Ponotration and f i t t i n g s

Donitrif ication Batch Reactor 1 ~ ~ ~ 7 % fiborqlass 5600 ga l Ponotrations arid f i t t i n g s

Troated Brino Iltorage 12*Dxl11H fiborglass 10500 pal Penetrations and f i t t i n g s

Ultra Violot Di.ssinfoction Uni t 10 tvo g p m unit..

Bydrochloric Acid Storage , h o d Sys. 6'DxI'B polypro doublo wall Ejoctor and pump P*notrationm and f i t t i n g s

Wothanol Storago and Feod Symtem Drum handling cbquipmont Hetoring pump r i r o safoty oquipment

?our

Control Bystom

~ s c o l l a n o o u s , piping. valves f i t t i n g s

i/ t o 1 Hp Transfor Rlmps

Intorfaco To Lltixting Plant nardvaro, soft1uar0, programming

LsxLxGx

6720 1000

6'120 1000

12600 1000

12000

2000 1200

600

5000 1600 2000

2000

7000

10000

13000

8000

-9Me

SUBTOTAL BASIC COMPONENTS 97440

Tota l Capital Enginooring ~on t ingonc ios @ PO*

Grand Total

97440 10000 20000

127440

TABLE 4 "DS OF PROCESS dlMICALS NEEDED PER DAY

NO BRINE ==-"-

913 1036

920 338 920 338

Wac1 lB26.r 913 345

wc12

meon 84 BB 84 BE

JEl - - - l l d m - l l d - - Total 1826** 1143 634 1150 627 1833 1374 Pounds

TABLE 5 5 COSTS PER M Y OF PROCESS CfiEnIw

NO BRINE CIIMICbL XXWDEEX SW DN* DN- SE2

* 18.25 20.71

99.98 36.68 99.78 36.67

Wac1 36.52** 18.25 6.90

cac12

neon 9.52 9.95 9.52 9.95

- U M L a Z z u-- Total 36.52** 44.54 39-53 126.27 69.32 118.03 57.38 $/Day

60.0 small -0UntS Of MkO UP NaCl V i 1 1 k roquirod. I n tho 1988 base yoar, 3350 pounds por day woro usod t o produce tho same quantity of va tor a t a c o s t of $ 67 per day.

**

m: Tho -0 costa aro for an avorage b i l y dolivory of .a IIGD @ 30 rg ~0311 or .IO IIGD @ 40 BIJ 110311.

m: Tho .bov. costs fncludo a11 chemicals roqulrod I t o oporate the ion uchanqo plant and the brino rocwory processes. Other costs such as operator tin and mintuunco vi11 roquiro p i l o t plant operation but u o not considered to be s igni f icant .