Treatment and Disposal of Pesticide Wastes - American Chemical

12 A Large Scale UV-Ozonation Degradation Unit Field Trials on Soil Pesticide Waste Disposal

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PHILIPC.KEARNEY, QIANG ZENG, and JOHN M. RUTH Pesticide Degradation Laboratory, Beltsville Agricultural Research Center, U.S. Department of Agriculture, Beltsville, MD 20705

Decomposition of farm-generated pesticide wastewater was demonstrated with a mobile 66-lamp ultraviolet (UV) unit and ozone. Aqueous solutions of 2,4-D (1086 ppm) and atrazine (4480 ppm) were degraded more than 80% in about 2-3 h, while paraquat (1500 ppm) was degraded more slowly. Dwell time, or the time the molecule was actually in the lamp unit, and concentration were two parameters that affected the rate of degradation. Mass spectra of the trimethylsilyl (TMS) derivatives of atrazine subjected to UV-ozonation revealed a number of dehalogenated, dealkylated s-triazines, paraquat yielded the 4-picolinic acid, and 2,4-D gave oxalic acid, glycolic acid and several four-carbon oxidation products. The economics of UV-ozonation as a pretreatment for land disposal compares favorably with incineration and other options open to the small pesticide user.

A frequent problem encountered by the p e s t i c i d e user i s safe waste d i s p o s a l of l i q u i d chemicals generated during or subsequent to a spray o p e r a t i o n . No accurate data are a v a i l a b l e on the t o t a l magnitude o f the p e s t i c i d e wastewater generated annually i n the United States, but some information i s a v a i l a b l e from one segment of the a g r i c u l t u r a l community. Commercial a e r i a l a p p l i c a t o r s spray about two-thirds of a l l a p p l i c a t i o n s made on a g r i c u l t u r a l and f o r e s t lands or roughly h a l f of a l l p e s t i c i d e a p p l i c a t i o n s i n the U.S. ( 1 ) . It has been estimated that i n a normal year 10,000 a i r c r a f t sprayed 180 m i l l i o n acres once and 350-380 m i l l i o n acres f o r those crops that r e c e i v e more than one application. I t i s also estimated that 10-60 g a l l o n s of wastewater are generated each day per spray plane, with concentrations ranging from 100-1000 ppm (2,3). Based on Seiber's estimates ( 4 ) , using 30 g a l l o n s and 500 ppm, i t may be

This chapter not subject to U.S. copyright. Published 1984, American Chemical Society

In Treatment and Disposal of Pesticide Wastes; Krueger, Raymond F., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1984.

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c a l c u l a t e d that roughly 10,000 g a l l o n s of wastewater containing 20 kg p e s t i c i d e are generated each year per plane. Estimates beyond t h i s are probably meaningless, because not a l l spray planes are engaged i n p e s t i c i d e a p p l i c a t i o n . Nevertheless, we suspect the o v e r a l l problem of safe wastewater i s s u b s t a n t i a l , based on the fact that more than 225.1 χ 10^ kg ( a c t i v e ingredient) of p e s t i c i d e were used on major f i e l d crops i n the U.S. i n 1982, of which 191 χ 10° kg were h e r b i c i d e s , 24.4 χ 10° kg i n s e c t i c i d e s . 2.4 χ 10° kg f u n g i c i d e s , 0.4 χ 10° kg m i t i c i d e s , 1.9 χ 10° kg fumigants, 2.2 χ 10° kg d e f o l i a n t s , and 2.7 χ 10" kg plant growth regulators (_5). Wastewaters are often generated at scattered or remote s i t e s , making t r a n s p o r t a t i o n and approved decontamination d i f f i c u l t and c o s t l y . F a u l t y waste d i s p o s a l techniques can a l s o p o t e n t i a l l y make a s u b s t a n t i a l c o n t r i b u t i o n to ground water contamination. A need e x i s t s , then, to develop new technology to solve a major problem faced by the p e s t i c i d e user that has p o t e n t i a l impact both w i t h i n and outside of the a g r i c u l t u r a l community. Recently we have reported on the use of u l t r a v i o l e t (UV) i r r a d i a t i o n , i n the presence of ozone, as a pretreatment p r i o r to s o i l d i s p o s a l of aqueous p e s t i c i d e s o l u t i o n s (6-8). Oxidative pretreatment was found to render a number of c h l o r i n a t e d compounds more biodegradable when exposed to the natural s o i l microflora. These studies were conducted p r i m a r i l y with a 450 W medium-prèssure mercury vapor lamp using C-labeled compounds to monitor the breakdown process both during UV-ozonation and i n s o i l s a f t e r a d d i t i o n of the oxygenated products. In a d d i t i o n , a commercial lamp unit containing 66 lowpressure mercury lamps was used for some experimental runs on l a r g e r volumes of chemicals. The o b j e c t i v e of the research reported here was to determine whether the 66-lamp unit would d e t o x i f y waste p e s t i c i d e s o l u t i o n s generated on a farm with high d a i l y p e s t i c i d e usage. Methods and

Materials

Location. The l o c a t i o n of the experiments was at the Farm Operations D i v i s i o n at USDA's B e l t s v i l l e A g r i c u l t u r a l Research Center (BARC). A d i v e r s e farming system i s i n operation at B e l t s v i l l e , i n c l u d i n g both experimental p l o t s and large acreages devoted to forage and g r a i n production for our l i v e s t o c k research. About 3000 acres are sprayed annually to c o n t r o l weeds, i n s e c t s , and diseases. Arrangements were made with the farm manager to supply us with excess p e s t i c i d e s o l u t i o n s remaining i n the spray tank at the end of a spraying operation. These s o l u t i o n s were stored i n 10-gallon s t a i n l e s s s t e e l milk cans and processed when time permitted, but u s u a l l y within several days a f t e r r e c e i p t .



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U V-Ozonation Degradation Unit

UV-Unit. The large unit i s an U l t r a - V i o l e t P u r i f i e r manufactured by Pure Water Systems, Inc., 23 Madison Road, P. 0. Box 1387, F a i r f i e l d , New Jersey 07006. The unit c o n s i s t s of 66 low-pressure mercury vapor lamps with a maximum energy output at 253.7 nm of 455 W. Each lamp i s encased i n a long quartz tube and the tubes are arranged w i t h i n a s t a i n l e s s s t e e l c y l i n d e r , approximately 40 cm i n diameter so that each lamp i s located 1.27 cm from each adjacent lamp ( F i g u r e 1). The volume of the lamp chamber i s 1 cubic foot (7.48 g a l l o n s or 28.32 L ) . L i q u i d i s d e l i v e r e d to the lamp unit by a pump with a flow r a t e of 8 to 40 L/min. A l a r g e s t a i n l e s s s t e e l h o l d i n g tank ( c a . 210 L) i s connected to the pump, and the lamp unit i s connected to the h o l d i n g tank, so that the l i q u i d can be r e c y c l e d through the lamp unit. The unit was mounted on a 8 χ 18 foot t r a i l e r , t i g h t l y secured, and moved some 5 miles to the p e s t i c i d e mixing and loading area on the BARC research f a c i l i t y ( F i g u r e 2 ) . Inspection of the unit during t r a v e l and at the farm s i t e showed no major problems i n making i t mobile for transport to other s i t e s for f u r t h e r research and development a c t i v i t i e s . Chemicals processed. Waste p e s t i c i d e s o l u t i o n s were c o l l e c t e d a f t e r spray operations during l a t e May, June, and J u l y of 1983, and consisted p r i m a r i l y of three compounds: 2,4-D [ ( 2 , 4 - d i c h l o r o phenoxy)acetic a c i d ] , a t r a z i n e (2-chloro-4-(ethylamino)-6( i s o p r o p y l a m i n o ) - j s - t r i a z i n e ) and paraquat (1,1'-dimethyl-4,4 b i p y r i d i n i u m d i c h l o r i d e ) . Our e f f o r t s were p r i m a r i l y d i r e c t e d at these p e s t i c i d e s , which are shown i n Table I together with t h e i r formulations and c o n c e n t r a t i o n s .

Table I.

P e s t i c i d e s , Formulations and Concentrations to UV-Ozonation i n the 66-Lamp Unit

Pesticide

Formulation

2,4-D

i s o o c t y l e s t e r , 4EC (low v o l a t i l e 68.2% a i , 31.8% i n e r t s

Atrazine

Aatrex 4L - 40.8% compounds 57.0%

Paraquat

29.1%

a i , 70.9%

a i , 2.2%

inerts

Subjected

Concentration (ppm) ester)1086

related 12000 1500

Routinely 38 to 152 L of wastewater were added to the l a r g e h o l d i n g tank (210 L c a p a c i t y ) and allowed to r e c y c l e through the



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T R E A T M E N T A N D DISPOSAL O F PESTICIDE WASTES

Figure 1. Lamp chamber containing 66 low-pressure mercury vapor lamps encased in quartz t u b e s , each s i t u a t e d 1.27 cm from adjacent lamp.

Figure 2. Mobile 66-lamp UV u n i t showing holding tank, pump and lamp chamber mounted on a t r a i l e r .



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system for about 30 min with no i r r a d i a t i o n . Some water remains i n the l i g h t chamber from the previous day's c l e a n i n g ; t h e r e f o r e , t h i s e q u i l i b r a t i o n time was necessary to e s t a b l i s h a uniform sample at time 0. P r i o r to a c t i v a t i n g the lamps, pure oxygen was fed i n t o the l i g h t chamber at a rate of 100 cc/min, and t h i s rate was maintained throughout the processing time. In some studies pure ozone was fed i n t o the l i g h t chamber from model GTC-1B ozone generator ( G r i f f i n Technics Corp. 66 Route 46, L o d i , New Jersey 07644) at a rate of 32 g per h from O2 feed gas (manufacturer's estimate). Samples were taken p e r i o d i c a l l y and returned to the P e s t i c i d e Degradation Laboratory for chemical analyses. Residue a n a l y s i s . A l l analyses were conducted by gas chromatography ( g l c ) using a flame i o n i z a t i o n detector and a 5% QF-1 column on Chromsorb W (DMCS) (2 mm i . d . by 1.8 Μ ) , 80/100 mesh; N2 flow rate at 40 mL/min and column temperatures of 160, 215, and 180°C f o r a t r a z i n e , 2,4-D, and paraquat, r e s p e c t i v e l y . For a t r a z i n e , 10 mL o f the commercial formulation (5000 ppm) was extracted 3 times (3x15 mL) with e t h y l a c e t a t e (EtAc). The EtAc was d r i e d with Na2S0^, f i l t e r e d , reduced i n volume under N2> and adjusted to 10 mL f o r glc a n a l y s i s . A sample spiked with 0.1 j i C i (U r i n g a t r a z i n e y i e l d e d an e x t r a c t i o n recovery of 99.6% v i a s c i n t i l l a t i o n counting. A s i m i l a r e x t r a c t i o n procedure was used for 2,4-D, with a recovery of 76.0%. For paraquat, 10 mL o f the commercial formulation (1500 ppm) were taken to dryness i n a r o t a r y evaporator, 300 mg of NaBH^ and 15 mL of 95% ethanol were added, and the s o l u t i o n was heated for 15 min at 60°C, cooled to room temperature, and c a r e f u l l y taken to dryness i n a r o t a r y evaporator. F i f t e e n mL of d i s t i l l e d water were added, and the s o l u t i o n was extracted 3 times (3x15 mL) with hexane. The hexane was d r i e d with ^ 2 ^ 0 4 , f i l t e r e d , reduced i n volume with a gentle stream of N2 and adjusted to a f i n a l volume of 10 ml for g l c a n a l y s i s . A sample spiked with O . l y C i (methyl ~ ^ c ) paraquat y i e l d e d an e x t r a c t i o n recovery of 68.8%. Laboratory s t u d i e s . S m a l l - s c a l e l a b o r a t o r y studies were conducted with the 450 W Hanovia lamp u n i t to i n v e s t i g a t e the products of UV-ozonation, which were analyzed on a gas chromatograph-mass spectrometer. P u r i f i e d aqueous samples of a t r a z i n e , paraquat, and 2,4-D were i r r a d i a t e d for 30 min i n the presence of oxygen, the water was removed under N 2 , and t r i m e t h y l s i l y l (TMS) d e r i v a t i v e s were prepared using b i s ( t r i m e t h y l s i l y l ) t r i f l u o r o a c e t a m i d e . A p o r t i o n of the TMS d e r i v a t i v e was i n j e c t e d i n t o a 30-M f l e x i b l e s i l i c a c a p i l l a r y column, coated with SE-30, and temperature programmed from 90 to 200°C at 5°C/min. The mass spectrometer i s a F i n n i g a n 4021 with an Incos data system, operated i n the e l e c t i o n impact mode, with an e l e c t r o n energy of 70eV and a source temperature o f 250°C.


TREATMENT AND DISPOSAL OF PESTICIDE WASTES

200 Results and D i s c u s s i o n


The r e s u l t s w i l l be discussed i n two s e c t i o n s . The f i r s t s e c t i o n w i l l deal b r i e f l y with our l a b o r a t o r y f i n d i n g s . The second s e c t i o n w i l l deal with the on-farm d i s p o s a l r e s u l t s . Laboratory s t u d i e s . A chromatogram of the t o t a l ion current of the TMS d e r i v a t i v e s of i r r a d i a t e d a t r a z i n e i s shown i n Figure 3. Peak assignments were based on reference standards and previous mass spectra of TMS d e r i v a t i v e s of 6 suspected m i c r o b i a l metabol i t e s of simazine [2-chloro-4,6-bis (ethy1amino)-^-triazine] a r e l a t e d j s - t r i a z i n e ( 9 ) . The region between scan 1250 and scan 1600 contained l a r g e peaks for d e r i v a t i v e s of hydroxyatrazine, N-ethylammeline, N-isopropylammeline and ammeline. The l a r g e s t peak was the d i TMS d e r i v a t i v e of hydroxyatrazine with a molecular ion at M/Z 341. The loss of c h l o r i n e i n the UV-ozonation process appeared to be complete, since no c h l o r i n e c o n t a i n i n g compounds were detected. Next i n abundance are d e r i v a t i v e s of compounds obtained by removing the e t h y l , i s o p r o p y l or both from hydroxy a t r a z i n e and replacement by hydrogen. Based on the mass s p e c t r a l data, the major products are shown i n Figure 4. I f the number of a c t i v e hydrogens i n the compound i s greater than the number of attached TMS groups, then isomeric forms of the d e r i v a t i v e are p o s s i b l e . That s i t u a t i o n i s well i l l u s t r a t e d by two mono TMS d e r i v a t i v e s of hydroxyatrazine, represented by the small g l c peak at scan 1288 and the much l a r g e r peak at scan 1335. The l a t t e r i s presumably the TMS-O-derivative and the other a TMS-N-derivative. The tri-TMS peaks for ammelide, N-ethyl ammelide, and N-isopropyl ammelide, with maxima at scans 1096, 1186, and 1208, r e s p e c t i v e l y , are very small i n comparison with the peaks between scan 1250 and scan 1600. The compounds g i v i n g r i s e to peaks at scan 734 to 744, scans 746 to 747, and scans 815-816 can be explained by assuming that one amino group on hydroxyatrazine has been removed e n t i r e l y and replaced by a hydrogen atom. The f i r s t two overlap to give what looks l i k e a s i n g l e large g l c peak at scan 744. In Figure 3, the proposed names of those compounds have been enclosed i n brackets to i n d i c a t e that the elemental composition i s probably c o r r e c t but that t h i s s t r u c t u r e has not yet been v e r i f i e d . It i s p o s s i b l e that the rings have been opened. S i m i l a r s t r u c t u r e s can be postulated f o r n e a r l y a l l of the small peaks between scan 400 and scan 700, but at least one requires a r i n g a l t e r a t i o n . These peaks, plus the ones between scan 200 and scan 400 and those between scan 1500 and scan 2000, r e q u i r e f u r t h e r study. The TMS d e r i v a t i v e of 4 - p i c o l i n i c acid ( i s o n i c o t i n i c a c i d ) was i d e n t i f i e d i n the TMS-treated r e a c t i o n mixture from the UV-ozonation of paraquat. This suggests a sequence of r e a c t i o n s , i n which Slade (10) , Funderburk et a l . (11) , and others have made



Figure 3. Chromatogram of the t o t a l ion c u r r e n t of the TMS d e r i v a t i v e s of a t r a z i n e subjected to UV-ozonations i n a 450 W medium-pressure mercury vapor lamp.


202


CI Downloaded by UNIV OF CALIFORNIA SAN DIEGO on January 15, 2016 | http://pubs.acs.org Publication Date: August 15, 1984 | doi: 10.1021/bk-1984-0259.ch012

Νί^Ν

'HCHN^^NHCHCH

H

N

2

3

Hc' 3

N^N

HCHN^J^NHCHCH,

HL

H,C'

2

N

/

\

OH

QH

Hc H,C'

I I I

OH Η,Ν-^NAJHJ Figure 4 .

Products r e s u l t i n g from UV-ozonation o f a t r a z i n e .



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U V-Ozonation Degradation Unit

203

e a r l y , major c o n t r i b u t i o n s (Figure 5 ) . UV-ozonation of the 4 - p i c o l i n i c acid y i e l d e d a number of products, which are c u r r e n t l y under i n v e s t i g a t i o n . With 2,4-D, n e i t h e r the t r i m e t h y l s i l y l ester nor the free acid was found among the r e a c t i o n products. The dominant chromatographic peaks i n the mixture represent the TMS d e r i v a t i v e s of g l y c o l i c a c i d , o x a l i c a c i d , and several four-carbon o x i d a t i o n products. Some of the l a t t e r have been t e n t a t i v e l y i d e n t i f i e d , and the work needed to confirm choices between a l t e r n a t i v e s t r u c t u r e s i s continuing. Some smaller chromatographic peaks probably represent d e r i v a t i v e s of s t r u c t u r e s containing f i v e or more carbon atoms. The nature of the products suggests r i n g fragmentation of 2,4-D. as opposed to the products derived from a t r a z i n e . Unpublished (X>2 e v o l u t i o n studies with ( ^ C - r i n g ) 2,4-D confirm extensive r i n g o x i d a t i o n of t h i s compound during UV-ozonation. Most of the products i d e n t i f i e d i n these studies are considerably more biodegradable than the parent m a t e r i a l s and should be degraded or bound more r a p i d l y than the parent compounds i n b i o l o g i c a l l y a c t i v e s o i l s . F i e l d s t u d i e s . Our research with the large UV r e a c t o r on the B e l t s v i l l e Research Farm was d i r e c t e d toward f i n d i n g the optimal conditions for destroying p e s t i c i d e wastewater using UV-ozonation. We d i d not concentrate on the m i c r o b i a l phase at t h i s time, other than i n a very l i m i t e d way. Figure 6 shows the decomposition of 38 and 152 L of 2,4-D at 1086 ppm. The l a r g e r volume (152 L) took about 5 times longer to achieve about a comparable degree of degradation, i e . s l i g h t l y over 80%. The d i f f e r e n c e would appear to be due to dwell time, or the time the molecule a c t u a l l y spends i n front of the l i g h t source as opposed to the time i n the 210 L h o l d i n g tank. Volume, then, i s one of the v a r i a b l e s that can be manipulated, and most of the subsequent research was done i n the 38 L or 10-gallon range. The e f f e c t of generated ozone on 2,4-D degradation i s shown i n Figure 7. High l e v e l s of ozone did not s u b s t a n t i a l l y a c c e l e r a t e the i n i t i a l o x i d a t i o n o f 2,4-D, but i t d i d increase the rate of degradation i n more d i l u t e s o l u t i o n during the l a t t e r part of the process. Our e a r l y r e s u l t s with a t r a z i n e i n d i c a t e d that t h i s molecule was somewhat more s t a b l e than 2,4-D (Figure 8). Preliminary r e s u l t s suggested that the i n i t i a l concentration of a t r a z i n e (12000 ppm) may have an e f f e c t on the rate of r e a c t i o n . We studied the e f f e c t s of d i l u t i o n i n our small lamp unit to determine whether lowering the concentration might a c c e l e r a t e the r a t e of degradation (Figure 9 ) . As the concentration decreased by a f a c t o r of 10, the time required for degradation also d r a s t i c a l l y decreased. The d i f f e r e n c e between 120 and 12 ppm i s i n d i s t i n g u i s h a b l e . We attempted to use t h i s f i n d i n g i n the large u n i t by adding 114 L of water to the holding tank and then slowly



204


Figure 5. Suggested r e a c t i o n sequence f o r o x i d a t i v e decomposi t i o n of paraquat based on the i d e n t i f i c a t i o n o f p i c o l i n i c a c i d by mass spectrometry.

οι ο

ι 5

ι 10

1

1

15 Time

20

1 —

25

ί 30

(hrs)

Figure 6. E f f e c t of volume s i z e on the r a t e o f degradation o f formulated i s o o c t y l e s t e r of 2,4-D at a concentration of 1086 ppm i n the 66-1 amp u n i t .



12.

1

0

205


KEARNEY ET AL.

2

3 4 Time (hrs.)

5

6

7

Figure 7. E f f e c t o f 02 and 0 fed i n t o the 66-1 amp chamber during U V - i r r a d i a t i o n o f formulated i s o o c t y l e s t e r o f 2,4-D at a concentration o f 1086 ppm. 3

c 60 c CO

ε * 40F

V

20^

2 Time

3 (hrs.)

Figure 8 . Degradation o f a t r a z i n e a t 12000 ppm v i a UV-ozonation in the 66-1 amp u n i t .



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T R E A T M E N T A N D DISPOSAL OF PESTICIDE WASTES

adding 38 L o f more concentrated a t r a z i n e to the water i n the r e s e r v o i r at a rate of 44 ml/min. The i n i t i a l concentrations would be extremely d i l u t e and thus more r a p i d l y decomposed. We could c a l c u l a t e the t h e o r e t i c a l concentration at each time p e r i o d and measure a c t u a l concentration by g l c (Figure 10). As i n previous runs, oxygen was fed i n t o the lamp chamber. The r e s u l t s were d i s a p p o i n t i n g , since the a t r a z i n e showed no appreciable breakdown during the mixing phase when the concentration would have been reasonably d i l u t e . The large volume (152 L ) and the consequently lower dwell time are probably r e s p o n s i b l e for the slow rate of decomposition. To optimize the c o n d i t i o n s , ozone from the G r i f f i n generator was fed i n t o the lamp chamber i n a non gradient run and at a concentration of 4480 ppm. When we used the same a i r flow rate for ozone as f o r oxygen, i e . 100 cc/min, we noted no s t r i k i n g d i f f e r e n c e i n the r a t e of degradation. I f , however, we operated the ozone generator at i t s maximum output, a very r a p i d d e c l i n e was measured (Figure 11). The i n i t i a l decomposition was rapid and was e s s e n t i a l l y complete a f t e r 2 h. Our research progress with paraquat has not been as extensive as with 2,4-D and a t r a z i n e . P r e l i m i n a r y r e s u l t s (Figure 12) suggest breakdown was slower than a n t i c i p a t e d . At t h i s point i t i s meaningless to compare the rates of breakdown of the three h e r b i c i d e s , since the concentrations and formulations are quite d i f f e r e n t . Two c r i t i c a l parameters that must be c o n t r o l l e d for the process to be e f f e c t i v e i n a reasonable time period are concentration and dwell time. These parameters w i l l Vary with each instrument, depending on design and capacity of the v a r i o u s units. Two important areas of research are underway to improve f u r t h e r the h y b r i d U V - 0 3 / s o i l d i s p o s a l system. A UV monitor coupled with a computer i s under i n v e s t i g a t i o n to make the u n i t s e l f contained with regard to chemical analyses and to automate c e r t a i n functions of the photochemical phase. Second, a m i c r o b i a l enrichment i n v e s t i g a t i o n u t i l i z i n g U V - O 3 products as substrates i s i n progress to s e l e c t and p o s s i b l y engineer degradators to a c c e l e r a t e the m i c r o b i a l phase. Economics. The manufacturer's r e t a i l p r i c e for the 66-lamp u n i t from Pure Water Systems, Inc. i s $35,000. The cost of operation i s based on energy usage, which i s 1.5 KWH (manufacturer's estimate); i f the current cost of e l e c t r i c i t y i s 5^/KWH, then the d a i l y operation would run $1.80/day or $657 annually. The cost of oxygen and the ozone generator are not included, nor do we have any estimate on long-term maintenance. It i s d i f f i c u l t to compare costs to other d i s p o s a l options. The Seiber report (4) l i s t e d the c a p i t a l cost for i n c i n e r a t i o n at $89,550, and y e a r l y operating cost of $106,500, based on 1978 estimates. The c a p i t a l and operating costs for our UV-ozonation


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12000 P P M 1200 P P M 120 P P M


12 P P M

20 Time (minutes)

Figure 9. E f f e c t o f c o n c e n t r a t i o n on the degradation o f formulated a t r a z i n e a t f o u r concentrations v i a UV-ozonation in a 450 W medium-pressure mercury vapor lamp.

Time (hours)

Figure 10. E f f e c t o f gradual i n c r e a s e i n c o n c e n t r a t i o n up to a c o n c e n t r a t i o n o f 2356 ppm on the degradation o f formulated a t r a z i n e up to a c o n c e n t r a t i o n o f 2356 ppm v i a UV-ozonation i n the 66-lamp u n i t .



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0L

I

1

1

1

1

1

L

1

2

3

4

5

6

7

Time

(hrs.)

Figure 11. E f f e c t o f 0o and O3 fed i n t o the 66-1 amp u n i t during U V - i r r a d i a t i o n o f formulated a t r a z i n e at 4480 ppm.

Paraquat U.V.-Ozonation 1500 PPM

Time (hrs.)

Figure 12. Degradation o f paraquat v i a UV-ozonation at 1500 ppm in the 66-1 amp u n i t .



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would appear to be more favorable than i n c i n e r a t i o n , but not as economical as p h y s i c a l treatment and the several land d i s p o s a l options. The advantages of the unit would be i t s m o b i l i t y ; r e l a t i v e ease of o p e r a t i o n ; low operating c o s t ; production of l e s s t o x i c , biodegradable products; and assurance of extensive degradation in a r e l a t i v e l y short p e r i o d of time when compared to ground disposal. Use of a company or product name by the Department does not imply approval or recommendation of the product to the e x c l u s i o n of others which may a l s o be s u i t a b l e .

Literature Cited 1. 2.

3.

4.

5.

6. 7. 8. 9. 10. 11.

Collins, H., personal communication. "Disposal of Dilute Pesticide Solutions," U.S. Environmental Protection Agency Report SW-176C (NTIS Report PB-297 985) 1979. Whittaker, K. F.; Nye, J. C . ; Wukarch, R. F . ; Squires, R. G.; York, A. C . ; Kazimier, H. A. "Collection and Treatment of Wastewater Generated by Pesticide Applicators," U.S. Environmental Protection Agency. Seiber, J. N. "Disposal of Pesticide Wastewater-Review, Evaluation and Recommendations," U.S. Environmental Protection Agency, OER, ORD, Draft Report 1981. Schaub, J. R. The Economics of Agricultural Pesticide Technology (in press) in J. L. Hilton, ed. Agricultural Chemicals of the Future. V o l . 8. Beltsville Symposia in Agricultural Research. 1983. Kearney, P. C . ; Plimmer, J. R.; Li, Z-M. 181st Am. Chem. Soc. Natl. Mtg. Abstr. PEST. 48, Atlanta, Georgia. 1981. Kearney, P. C . ; Plimmer, J. R.; Li, Z-M. Proc. 5th Int. Congr. Pestic. Chem. IUPAC 1983. 4,397. Kearney, P. C . ; Quiang, Z . ; Ruth, J. M. Chemosphere (in press) 1983. Lusby, W. R.; Kearney, P. C. J. Agric. Food Chem. 1978, 26, 635. Slade, P. Nature 1965, 207, 515. Funderburk, H. H.; Negi, N. S.; Lawrence, J. M. Weeds 1966, 14, 240.

RECEIVED April 16, 1984


Treatment and Disposal of Pesticide Wastes - American Chemical

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