Removal of Bromate and Perchlorate in Ozone/GAC Systems

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DO concentration (2-6 mg/L). The influent was stored in a headspace-free container, with a floating cover made of stainless steel, in order to maintain the DO concentration. The GAC was extensively contacted with CUW in order to exhaust the adsorptive capacity of the carbon. The GAC was preloaded with 7,200 bed volumes of chlorinated CUW with an influent DO concentration of approximately 4 mg/L and a total EBCT of 5 minutes. CUW was not dechlorinated during this portion of the preloading due to the operational difficulty that would have caused because of the high flowrate (-300 mL/min). Since Kirisits et al. (1998) observed 80 percent bromate breakthrough from a non-biologically active GAC filter after 6,500 bed volumes, it is unlikely that significant abiotic bromate removal was taking place in the BAG filter after the preloading period. In order to stimulate biological growth, the filter was subsequently operated for 500 BV with dechlorinated CUW and 2 mg/L DO. During this time, the filter had a total EBCT of 60 minutes, with the sampling ports allowing the evaluation of 15-, 30-, 45-, and 60-minute EBCTs. . Floating Cover Influent: CUW 20 ng/L Bromate pH7.5 0.3 mg/L Nitrate 2-6 mg/L DO Sampling Ports 30.6-cmBAC Bed Height 3-mm Gass Beads NOTE: Not to Scale Peristaltic Pump 5.1-cm Inner-Diameter Figure 2.3 Schematic of multi-port BAC filter using CUW 24
Backwash ing the BAG filters Two of the small BAG filters using CUW (Figure 2.1) were backwashed to determine its effect on bromate removal. The backwash water consisted of filter effluent rather than the usual filter influent so that the microorganisms would not be exposed to higher ammonia and DOC concentrations than usual. The backwashing procedure consisted of 10 minutes of fluidization with approximately 35 percent bed expansion. The carbon was mechanically agitated from the top of the column to promote mixing in the bed. Heterotrophic Plate Counts Heterotrophic plate counts (HPCs) were run with water samples collected before and after backwashing. Bacto® R2A agar (Difco Laboratories, Detroit, MI) was the medium used. 9.1 g of R2A was dissolved per 500 mL of DDW. This was heated to approximately 70 °C and stirred for 20 minutes to dissolve the medium. The medium was then sterilized by autoclaving (Eagle/Century Series, Amsco Scientific) for a 20-minute liquid cycle. 5-mL portions of the medium were poured into sterile petri dishes and allowed to solidify. The Membrane Filter Method was performed according to Standard Method 9215D (APHA, AWWA, and WEF, 1995). Various volumes of water were filtered through sterile, gridded filters (0.45 ^im, Millipore, Bedford, MA). Each filter was placed in a petri dish and incubated in the dark for a minimum of 5 days at 25 °C. Denaturing Gradient Gel Electrophoresis Denaturing gradient gel electrophoresis (DGGE) was used to investigate the diversity of the microbial population in the BAG filters. The DGGE technique consists of extracting ribosomal DNA (rDNA) from the microbial community, amplifying it by the polymerase chain reaction (PCR), and then applying it to a polyacrylamide gel that has a gradient of DNA denaturing agents. As the rDNA migrates through the gel, it melts at a particular location in the denaturing gradient. The position at which this melting occurs is a function of the base pairs in the DNA fragment. When the fragment melts, its motility ceases. Thus, one will obtain a DGGE pattern containing different bands that have 25
Page 1: AWWA Research Foundation Removal of
Page 4 and 5: The mission of the AWWA Research Fo
Page 6 and 7: Disclaimer This study was funded by
Page 8 and 9: Serum Bottle Experiments ..........
Page 11 and 12: TABLES 1.1 Bromate removal in DFE a
Page 13 and 14: FIGURES 1.1 Effect of influent diss
Page 15: 3.32 Perchlorate removal vs. nitrat
Page 18 and 19: Perchlorate and chlorate salts are
Page 21 and 22: EXECUTIVE SUMMARY Bromate (BrO3~) a
Page 23 and 24: scale ozone-BAC plants is likely du
Page 25 and 26: RECOMMENDATIONS 1. To utilize BAG f
Page 27 and 28: CHAPTER 1. INTRODUCTION BACKGROUND
Page 29 and 30: PREVIOUS STUDIES - BROMATE 1 Siddiq
Page 31 and 32: ethanol was required to stimulate e
Page 33 and 34: were not measured, they can be pres
Page 35 and 36: one year prior to this experiment,
Page 37 and 38: 2.0 - e • • 8 i 8 a
Page 39 and 40: i S I i.o - 1.4 - 1.2 - 1.0 - 0.8 -
Page 41 and 42: ut the concentrations of oxygen and
Page 43 and 44: species that is able to reduce perc
Page 45 and 46: CHAPTER 2. MATERIALS AND METHODS MA
Page 47 and 48: BAG was formed by extensively prelo
Page 49: Floating Cover 1 Influent: LMW 20 (
Page 53 and 54: Table 2.2 Agar recipe for plating e
Page 55 and 56: Streaked individual colony morpholo
Page 57 and 58: METHODS UTILIZED FOR PERCHLORATE RE
Page 59 and 60: Metal-Catalyzed GAG Filter Experime
Page 61 and 62: perchlorate, nitrite, nitrate, and
Page 63 and 64: Table 2.5 Serum bottle experiment 2
Page 65 and 66: CHAPTER 3. RESULTS AND DISCUSSION B
Page 67 and 68: a two-week period. Over the two-wee
Page 69 and 70: To establish the effect of backwash
Page 71 and 72: o S 25 20 - 15 - 10 - O 50-min EBCT
Page 73 and 74: In general, the average percent bro
Page 75 and 76: measured nitrate concentration and
Page 77 and 78: Two data points in each of Figures
Page 79 and 80: 90 - ^ 80 - 70 - J 60 - o 11 1 50 -
Page 81 and 82: ench-scale and full-scale B AC filt
Page 83 and 84: omate removal was sustained (Figure
Page 85 and 86: Fraction Perchlorate Remaining, Fra
Page 87 and 88: Figure 3.18 Rods and cocci from the
Page 89 and 90: seen that the BAG samples contain a
Page 91 and 92: Bromate Reduction in DDW with Exoge
Page 93 and 94: The mass balance on nitrate + nitri
Page 95 and 96: N2O was not detected and no evidenc
Page 97 and 98: Table 3.10 Results of dilution-to-e
Page 99 and 100: 0 so o U ).0 - I 5.0 U ffl Addition
Page 101 and 102:
o I Io U D o ou - 50 1 40 - 30 - 20
Page 103 and 104:
Wash Tests Table 3.11 lists the res
Page 105 and 106:
The next step was to determine if p
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Jar cio4- 42.8 40.4 40.5 41.1 6 C/C
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of nitrate on perchlorate reduction
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Effluent Perchlorate, C/C l.U 0.8 -
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was decreased. It is interesting to
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1 1.6 1.4 - 1.2 - .1.0- 1.5mg/L Inf
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or 1.5 mg/L nitrate showed no perch
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^——s 0 4 0 234 Incubation Time
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Figure 3.43 illustrates the differe
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Figure 3.44 Rods and protozoa from
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CHAPTER 4. ACTIVITIES AT THE METROP
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Perchlorate is only found in CRW, a
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Residual ozone. To reduce sample ov
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^ influent 0 effluent A mid • inf
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Effect of Nitrate The background ni
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Table 4.2 Control study for chemica
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PILOT-SCALE MOBILE PILOT PLANT STUD
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Mobile Pilot Plant Ozone The ozonat
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Table 4.4 Mobile pilot plant operat
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p o O. i Fraction Bromate Remaining
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CHAPTER 5. SUMMARY AND CONCLUSIONS
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Bromate removal increased as the in
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virgin Norit GAC showed an ion exch
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Microscopic examination of the biom
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CHAPTER 6. RECOMMENDATIONS TO UTILI
Page 156 and 157:
Brock, T. D., M. T. Madigan, J. M.
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Kirisits, M. J., V. L. Snoeyink, an
Page 160 and 161:
Rogers, K. 1997. Water Contaminated
Page 163 and 164:
ABBREVIATIONS AWWA AWWARF American
Page 166:
AWWA Research Foundation Advancing
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Removal of Bromate and Perchlorate in Ozone/GAC Systems

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