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1 OCCURRENCE AND CONSEQUENCES OF INCREASED BROMIDE

2 IN DRINKING WATER SOURCES

3

4 Nancy McTigue, Katherine Graf and Richard Brown, EE&T

5

6 ABSTRACT

7 Elevated levels of brominated disinfectant by-products (DBPs) have been reported 

8 recently by some drinking water utilities. Some of these occurrences have been correlated with 

9 upstream discharges of bromide-containing wastes from coal-fired power utilities, hydraulic 

10 fracturing wastewater discharges and other industrial sources. This paper discusses this problem 

11 in terms of the formation chemistry of disinfectant by-products when bromide is present, 

12 regulatory changes that have resulted in the increased use of bromide by industries and discusses 

13 the potential number of water utilities impacted by these discharges. The authors investigated 

14 this problem through a review of published and unpublished sources, and through interviews 

15 with utility personnel and state regulators.

16 Formation of By-Products During Disinfection 

17 The formation of unwanted and possibly carcinogenic by-products as a result of the 

18 disinfection of drinking water was first recognized by researchers in the 1970s. The first 

19 regulations to limit the levels of these DBPs, a term used to collectively describe the suite of 

20 products resulting from reactions of free chlorine and other oxidants with natural organic matter 

21 (NOM) and other substances in the water, were promulgated by the United States Environmental 

22 Protection Agency (USEPA) in 1979. Regulations have become more stringent since then as 

23 knowledge of the presence, formation and health implications of DBPs has increased since the 

24 1970s. Over 500 DBPs have been identified, although just a few have been regulated. 
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25 Disinfection of drinking water with free chlorine has made a significant contribution to 

26 the reduction in waterborne disease. In spite of the positive benefit, it has also been shown that 

27 DBPs can have adverse health effects after prolonged (i.e., lifetime) exposures (AWWA 2004; 

28 USEPA 2006). In particular, the DBPs most commonly associated with these observed adverse 

29 health effects have been halogen substituted organics, typically DBPs containing chlorine or 

30 bromine. At present, while there are a large variety of complicated halogen substituted DBP 

31 compounds believed to result from chlorination of drinking water, the only currently regulated 

32 DBPs are total trihalomethanes (TTHM) and haloacetic acids (HAA5). TTHMs are the sum of 

33 chloroform (CHCl3), bromodichloromethane (CHBrCl2), dibromochloromethane (CHBr2Cl) and 

34 bromoform (CHBr3). HAA5 are the sum of monochloroacetic acid, (C2H3ClO2) dichloroacetic 

35 acid (C2H2Cl2O2), trichloroacetic acid (C2HCl3O2), bromoacetic acid (C2H3BrO2) and 

36 dibromoacetic acid (C2H2Br2O2).

37 Chlorine added to drinking water reacts quickly with reduced substances (e.g. reduced 

38 iron), plus it also reacts quickly with ammonia, organic compounds containing nitrogen, and the 

39 bromide ion. Any chlorine not consumed by these reactions can produce disinfection, but can 

40 also produce DBPs if enough DBP precursor material is present and if unreacted free chlorine 

41 residual remains in water for a long enough time for the DBP formation reactions to occur. 

42 Most chlorine in drinking water is consumed in oxidation reactions, including oxidation 

43 of organics (Jolley 1975). However, some added chlorine substitutes into organic compounds to 

44 produce a chlorine substituted DBP, and some of the added chlorine can transfer its 

45 oxidative/disinfecting power to another compound. In the latter case, chlorine can: (a) react with 

46 ammonia to produce chloramines (typically monochloramine or NH2Cl), (b) react with nitrogen 

47 containing organics to produce organic chloramines, and (c) oxidize bromide to bromine.
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48 Impact of Bromide on DBP Formation 

49 If bromide is present, it affects the formation of DBPs in a number of ways. Free 

50 chlorine reacts with bromide to produce free bromine in water, and the bromine reacts 

51 analogously to free chlorine in: (1) oxidation of any reduced metals still present, (2) disinfection, 

52 (3) reaction with ammonia to produce bromamines (typically dibromamine), and (4) formation of 

53 bromine substituted DBPs if DBP precursor material is present. 

54 Therefore, in water, chlorine can react directly with organic DBP precursors, but can also 

55 react first with bromide, and then the resulting bromine can react with organic DBP precursors to 

56 produce brominated organic DBPs. This is important for a number of reasons:

57 1. There are reportedly greater health risks attributed to brominated DBPs than 

58 chlorinated DBPs

59 Risks from cancer and other adverse human health effects are generally thought to be 

60 greater for bromine substituted DBPs than with analogous DBPs containing chlorine instead of 

61 bromine (Cantor et al., 2010). For example, the concentration of species that gives a one in a 

62 million (1/1,000,000) lifetime cancer risk for dibromochloromethane is 0.6 μg/L on a mass basis. 

63 For chloroform it is 6 μg/L. Therefore, on a mass basis it appears that dibromochloromethane 

64 has 10 times greater lifetime cancer risk than chloroform. However, when the difference in 

65 molecular weight is taken into account (119.4 μg/μmol for chloroform and 208.3 μg/μmol for 

66 dibromochloromethane), the difference on a molar basis is even higher (~17.4 times greater).

67 2. The regulatory limits for drinking water compliance are mass based not molar based

68 Drinking water facilities are currently faced with two regulatory limits for halogen 

69 substituted DBPs: TTHM (sum of four compounds listed above) ≤ 80 μg/L and HAA5 (sum of 

70 five compounds listed above) ≤ 60 μg/L. The regulatory limit is simply based on taking the 
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71 mass concentration of each compound, without correcting for molar weight, and adding each 

72 numerical value for the four or five compounds involved. Therefore, a water system with no 

73 bromide in the background source water will be in compliance with the TTHM limit if they have 

74 60 μg/L of chloroform and no detectable brominated THMs. In this case, about 0.5 μmol/L of 

75 TTHMs were produced. However, if nothing else changes but enough bromide is added to 

76 produce bromodichloromethane instead of chloroform, then 0.5 μmol/L of TTHM will produce 

77 ~82 μg/L which could create compliance difficulties. Therefore, a water system currently in 

78 compliance with federal and state requirements may no longer be in compliance if bromide is 

79 added to the drinking water source in amounts sufficient to increase the amount of brominated 

80 DBPs produced.

81 3. There is increased formation of brominated DBPs due to the greater reactivity of 

82 bromide

83 The above suggests that the presence of bromide during chlorination can increase the 

84 numerical value of the regulatory compliance value even if the same amount of organic precursor 

85 material is present and even if the same molar concentration of DBP is produced. However, 

86 since free bromine in drinking water reacts more quickly than free chlorine, more DBPs (on a

87 molar basis) will be produced since the increased reactivity of bromine will mean more oxidation 

88 of organics by bromine, as well as bromine substitution reactions.

89 A number of factors determine the formation and ultimate composition of the total THM 

90 – water quality parameters, residence time, amount of disinfectant, temperature, type and amount 

91 of precursor. For any given utility, the relative amount of each of the four THMs can vary 

92 during the year because of changes in these factors. Until recently, however, except in coastal 

93 locations where bromide can be seasonally introduced because of salt water influences, US 
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94 utilities have generally seen more chlorinated than brominated species in their distribution 

95 TTHM formation. TTHM data collected from 500 water plants during the Information 

96 Collection Rule (1997– 1998) showed that chloroform dominated the other three species, and 

97 was present at the highest mean concentration (McGuire, et al 2002).

98 SOURCES OF BROMIDE IN RAW WATER

99 Bromide is a trace element in seawater and is rarely observed naturally occurring at 

100 significant concentrations in fresh surface waters in the US (Bowen 1979). Typical seawater 

101 concentration is about 65,000 μg/L, resulting in some coastal drinking water supplies having 

102 elevated levels of bromide due to seawater intrusion. Bromide from seawater can influence 

103 drinking water sources either through intrusion, or through connate seawater (seawater that is 

104 trapped in geological formations.) 

105 Bromide in source water can come from seawater, but it can also come from a number of 

106 anthropogenic sources. In the past, before leaded gasoline was banned in the US, gasoline 

107 emissions were a contributing factor because leaded gasoline contained additives of brominated 

108 compounds. Road salt and some fertilizers can also contribute bromide to source waters. 

109 Recently, however, there have been reports of increased bromide in source waters due to 

110 industrial activities, including hydraulic fracturing, air pollution control in coal-fired power 

111 plants and textile production. 

112 A possible contributor to bromide in the source water is effluent from coal-fired power 

113 plants. For some of these power plants to produce a clean air effluent they must use wet 

114 scrubbers that can introduce bromide into the waste stream, which is then discharged to a surface 

115 water body. Another possible contributor is natural gas production. The development of this 

116 fuel requires a significant amount of water and if the water is returned to a water body it is 
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117 typically high in bromide. Although most unconventional oil and natural gas wastewater is 

118 disposed of through deep underground injection, wastewater processed through surface treatment 

119 plants may have substantially increased bromide levels. Another possible bromide source is 

120 textile mill processes that use brominated compounds to flameproof fabrics.

121 These sources have been studied to some extent but their full impact on the water utility 

122 population is not yet well understood, as utilities are just beginning to see the impact of bromide 

123 on their DBPs. Some water utilities have recently noticed an increase in the brominated fraction 

124 of their DBPs. A number of utilities with no previous violations have experienced DBP MCL 

125 violations due to this brominated fraction. Since bromide is unregulated and has no known health 

126 impact, bromide has not historically been monitored in source water, except in research studies. 

127 BROMIDE LEVELS IN SOURCE WATERS AND IMPACTS ON DBP SPECIATION

128 As reported by Amy and colleagues, in 1994 a source water bromide survey of 100 

129 utilities over 18 months was conducted, showing bromide levels for large and small randomly 

130 selected utilities ranged from <5 to 429 μg/L. At targeted utilities where the researchers 

131 suspected that high levels of bromide existed, the average bromide level was 210 μg/L. When 

132 all data were considered, the overall average of all data from the 100 utilities was about 100 

133 μg/L. Lower bromide levels were found in lake sources. The median (50-percent) value for 

134 river and groundwater sources was approximately 60 μg/L, whereas, that for lakes the median

135 was approximately 30 μg/L. The 90 percent values for river and groundwater sources were 

136 approximately 300 μg/L (Amy 1994).

137 During the Information Collection Rule, all large utilities serving more than 100,000 

138 customers were required to sample a number of water quality parameters, including source water 

139 bromide and distribution system THMs and HAAs. Samples were analyzed from 500 water 
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140 plants during an 18 month period in 1997 – 1998. A shift in speciation toward more brominated 

141 DBPs as bromide in the source water increased was noted in the analysis of the database. 

142 (McGuire et al 2002). However, the range of speciation within each category of bromide 

143 concentration was quite large. About 80 percent of the samples analyzed for bromide in source 

144 water were less than 100 μg/L of bromide.

145 The USEPA reported on the results of an extensive nationwide survey of DBP 

146 occurrences in drinking water. They found that bromide levels in source water above 400 μg/L 

147 were associated with increased levels of DBPs in the finished water (Weinberg 2002). 

148 Preliminary data from an extensive monitoring effort taking place in North Carolina 

149 indicate that the bromide levels in some watersheds are elevated, especially during periods of 

150 low stream flow. In one river, bromide levels as high as 1 mg/L were measured (Greune 2013).

151 The percentage of chloroform in the TTHM collected in the distribution system of a drinking 

152 water utility on that river decreased significantly with increased bromide levels. At the highest 

153 bromide source concentration, nearly all of the TTHM was composed of brominated species. 

154 Other recent studies have reported on the same trend.

155 COAL FIRED POWER PLANT DISCHARGE POTENTIAL IMPACT ON WATER 

156 QUALITY

157 Recently finalized air regulations for power plant emissions may result in more 

158 brominated compounds being used by these power plants, and ultimately more bromide wastes 

159 being discharged to receiving streams. In December 2011, the USEPA approved new strict air 

160 discharge limits, referred to as the Mercury and Air Toxics Standards (MATS), targeting oil- and 

161 coal-fired electrical power generating facilities. These requirements are scheduled to take effect 

162 in 2015 (USEPA 2012). MATS will target reductions in emissions of metals (mercury, arsenic, 
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163 chromium, nickel), acid gases (hydrochloric and hydrofluoric), particulate matter, sulfur dioxide 

164 (SO2), and nitrous oxides (NOx). Figure 1 shows a USEPA prepared map of the US facilities 

165 with coal, oil, or both coal and oil units at the power plant and their relative capacities in 

166 megawatts (MW) (USEPA 2011).

167 It is estimated that 1,100 coal-fired units and 300 oil-fired units at 600 power plants will 

168 be impacted by the MATS requirements (USEPA 2011). Power plants that use coal as a fuel are 

169 most likely to install wet scrubbers and are the focus of this report.

170 The Flue Gas Desulfurization (FGD) process, also known as air scrubbers, is the 

171 preferred air pollution control technology for controlling SO2 and sometimes mercury. The new 

172 MATS SO2 and mercury requirements could result in installation of more wet or dry scrubbers. 

173 Economic analysis will dictate which is selected, but wet scrubber technology is generally 

174 favored when coal with higher sulfur content is used, as is the case in much of Eastern US. 

175 Mercury is present in flue gas in varying percentages, depending on the origin of coal, in 

three basic forms (Kellie et al, 2005): particulate-bound, elemental (Hg0176 ), and oxidized mercury 

in gas form (Hg2+ 177 ). The particulate-bound mercury can be easily removed by electrostatic 

178 precipitators (ESP) or fabric filters (Bustard et al. 2003). The oxidized mercury has a tendency 

179 to stick to particulate matter and is water soluble (Blythe et al. 2002). Consequently, it can be 

captured by the ESP, fabric filters, or wet/dry scrubbers. However, Hg0180 is highly volatile and 

181 insoluble in water and is thus not readily removed by typical air pollution control devices. The 

182 relative concentration of chloride and bromide that naturally occurs in the coal dictates the form 

183 of mercury that is present. In general bromide is lower in lignite and sub-bituminous coal, 3 ppm 

184 and 1 – 2 ppm, respectively, than in bituminous coal, 20 ppm (Buschmann 2005). Therefore, the 

185 addition of bromide-containing salts (usually calcium bromide) to the coal combustion unit can 
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convert the mercury into the more water soluble Hg2+ 186 form. This soluble mercury is better 

187 removed by the wet scrubbers used to clean flue gasses. 

188 However, while the mercury in the wastewater can be removed prior to discharge into a 

189 receiving stream, the added bromide is not typically removed and ends up being discharged. A 

190 US Department of Energy (USDOE) National Energy Technology Laboratory (NETL) report 

191 (Benson et al. 2007) documented the correlation between bromide in or added to the coal and the 

192 concentration of bromide in the FGD wastewater, referred to as liquor in their study. The US 

193 DOE NETL results in Figure 2 show that after a couple weeks the FGD liquor concentration of 

194 bromide is equal to the concentration that is added to the coal. 

195 In 14 full-scale coal-fired power plant tests using calcium bromide (CaBr2) to oxidize 

196 elemental mercury, greater than 90-percent of the mercury was oxidized with the addition of 25 

197 to 300 ppm bromide by weight of coal (Chang et al. 2008). This range is wide due to the coal’s 

198 natural abundance of chlorine and bromine giving the coal varied natural performance for 

199 oxidizing mercury. Using this information, it is possible to calculate the amount of bromide that 

200 could be discharged as a function of the amount of energy produced by the power plant as 

201 described below.

202 A power plant with a 1 MW capacity operated 24 hours a day, 365 days a year would 

203 produce 8,760,000 KWh/year. According to the US Energy Information Administration (US 

204 EIA) (2013a) it takes 1.07 lbs of coal to produce 1 kWh. This means that for each MW of 

205 electrical power plant capacity, a coal-fired power plant would require 9,373,200 lbs coal/year or 

206 25,680 lbs coal/day. With the range of 25 to 300 ppm for bromide noted in Chang et al. (2008), 

207 the amount of bromide added to the system each day per MW of power is estimated as follows:

208
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209

210

211 Therefore, depending on the amount of bromide present or added to the coal, the 

212 production of 1 MW of power would result in the addition of 0.51 to 6.2 lb/day of bromide. 

213 Further, according to the DOE NETL report (Benson et al. 2007) all of the bromide added to the 

214 power plant is discharged into receiving streams; these calculations indicate that between 0.51 

215 and 6.2 pounds per day of bromide per MW of power produced will be discharged into receiving 

216 streams.

217 Currently, there are no bromide discharge standards. However, the new MATS 

218 requirements may increase bromide discharges from coal-fired power plants in a couple of ways. 

219 First, coal-fired power plants have already or are going to be adding wet scrubbers in response to 

220 SO2 removal requirements of MATS. Even if the coal source used has a low bromide content, 

221 the increased use of wet scrubbers to remove SO2 as a consequence of the MATS requirements 

222 will result in more bromide releases, even in situations where bromide is not added to improve 

223 mercury removal. If the coal source is high in bromide, these wet scrubber discharges will 

224 include even greater amounts of bromide. Furthermore, the increased need to remove mercury 

225 in coal-fired power plants may cause bromide to be added, unless the coal is already naturally 

226 high in bromide. In either case the amount of bromide released to receiving waters will be 

227 greater than before the wet scrubber was added. 

228 Figure 3 was prepared by the USEPA (2011) and illustrates the projected improvement in 

229 mercury releases in different states as a consequence of the MATs mercury requirements. A 

230 large portion of these improved mercury releases are expected to be due to increased use of 

231 bromide and/or wet scrubber technology. Power plants that have installed scrubbers in response 
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232 to the MATS may move to a higher sulfur coal content since they already have control 

233 technology in place. It is generally less expensive than the low sulfur coal (USEIA 2013b) and 

234 has a higher BTU value (Bowen 2008). Bituminous coal has higher sulfur content and also, as 

235 previously discussed, has higher bromide content. The lower cost of bituminous coal alone 

236 could increase scrubber use, wastewater volume and bromide concentrations. 

237 According to USEPA (2013) 85 percent of the FGD systems installed in the US are wet 

238 systems. Generally, it is more cost effective to install a wet scrubber rather than a dry scrubber 

239 for a power plant burning a higher sulfur content in the coal, >2% by weight. Also, dry and 

240 spray dry scrubbers are applied to smaller units, less than 300 MW (USEPA 2013). Figure 4 is 

241 from a USDOE NETL report (Miller et al. 2006), showing that flue gas desulfurization capacity

242 is projected to increase to 231 GW by year 2020. If 90 percent of the FGD processes installed 

243 continue to be wet scrubbers, then 208 GW of the electrical power generating capacity in 2020 

244 will employ wet scrubbers. One vendor promoting the use of bromide injection for mercury 

245 control claims a combined total of 8,000 MW of US utility coal-fired boilers use their technology 

246 (Mcilvaine Company 2012). 

247 As discussed previously, bromide is present in the coal burned, and is often added as 

248 calcium bromide in the FGD process. As the use of FGD increases, the amount of bromide that 

249 is ultimately released to receiving waters may increase dramatically, resulting in adverse impacts 

250 on downstream drinking water plants. 

251 Consequently, the new, stringent air emissions regulation designed to lower mercury 

252 emissions may result in increased bromide discharges to drinking water sources as power plants 

253 change technology or coal sources in efforts to meet the requirements. Public drinking water 

254 sources may, in turn, experience difficulty in meeting regulatory requirements and may see an 
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255 increase in the production of more brominated DBPs with greater health risks than analogous 

256 chlorinated DBPs to drinking water consumers, as previously discussed.

257 Bromine disinfectants, also referred to as bromine biocides, are also used as an 

258 alternative to chlorine for cooling tower disinfection. Regulations have made it particularly 

259 difficult to use chlorine to control cooling tower biological fouling. However, power plant 

260 cooling water discharges containing bromine are controlled by the NPDES permits which restrict 

261 discharge of bromine compounds to not more than two hours per day. This could possibly result 

262 in a bromide spike and therefore a TTHM spike at a downstream water treatment plant.

263 HYDRAULIC FRACTURING POTENTIAL IMPACT ON WATER QUALITY

264 Unconventional natural gas development (UNGD), also known as hydraulic fracturing or 

265 “fracking”, which made up 23 percent of natural gas production in 2010 in the United States, is 

266 increasing each year and is expected to grow to 49 percent by 2035 (USDOE 2012). Hydraulic 

267 fracturing introduces water to the shale formation (millions of gallons per well) in order to 

268 increase permeability through fracture generation, and thus this water has the potential to return 

269 to the surface with gas. Anywhere from 10 to 80 percent of the injected volume may return to 

270 the surface as wastewater. The wastewater from this entire process includes both “flowback” 

271 and “produced water.” Flowback is the fracturing fluid that quickly returns to the surface, and 

272 produced water is the fracturing fluid that takes longer to return to the surface (Robart 2012; US 

273 EPA 2010).

274 Both flowback and produced waters are enriched with materials from the shale formation, 

275 such as minerals, brines, hydrocarbons, and naturally occurring radioactive materials. The 

276 longer the fluid takes to return to the surface, the greater the concentration of formation materials 

277 (Hayes 2009). Flowback water management is usually done onsite through minimization, 
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278 recycling and reuse within operations. Produced water management may also include treatment 

279 followed by surface water discharge, such as at publicly owned wastewater treatment plants 

280 (POTWs) or centralized brine treatment plants (CWTs). Existing CWTs are exempt from the 

281 regulations passed in 2008 that included restriction to TDS discharges. This could result in the 

282 elevated TDS concentrations, including elevated bromide and chloride found in flowback and 

283 produced water being released in the effluent.

284 Table 1 shows the ranges of bromide concentration, the average wastewater flow for the 

285 facility, and the receiving watershed for a number of treatment facilities in Pennsylvania that 

286 treat hydraulic fracturing wastewater and discharge to surface water bodies. Clearly, significant 

287 quantities of bromide are being introduced to receiving waters by these facilities. The West 

288 Virginia Department of Environmental Protection (WVDEP) also collected 13 produced water 

289 samples with bromide levels ranging from 1,290 to 525,000 μg/L, with an average concentration 

290 of 185,000 μg/L.

291 For example as shown in Table 1, the Josephine Brine Facility, located on the 

292 Conemaugh River within the Allegheny watershed, typically discharging 155,000 gal/day with 

293 an effluent bromide concentration range from 601,000 to 8,290,000 μg/L. However, to fully 

294 understand the magnitude of this effluent flow and concentration, the receiving stream flow must 

295 be known. The closest USGS gauge station (USGS 03041500) to the brine facility’s discharge 

on the Conemaugh River measured an average flow of 1,629 ft3296 /s (cfs). This means that the 

297 brine effluent flow makes up 0.015 percent of the total river flow, diluting the bromide 

298 concentration by the same fraction. With that dilution factor, the bromide concentration added to 

299 the river at the discharge location is approximately 88 to 1,220 μg/L. As discussed previously, 

300 concentrations seen in US rivers by Amy et al. in 1994 averaged around 60 μg/L. Since 1994 
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301 pre-dates the ongoing shale gas development boom, those concentrations could be considered the 

302 background concentration. This means that the lower limit of Josephine Brine Facility’s bromide 

303 effluent concentration is more than double background and the upper limit increased bromide 20 

304 fold.

305 Other Industries

306 Other industries could have wastewater effluents with elevated bromide. Any industry 

307 with mercury and SOx emissions could also have or will have wet scrubber installations as well. 

308 Therefore, their effluent streams could be a new source of bromide to receiving streams. 

309 Brominated flame retardants are used in a variety of consumer products and several of 

310 those are produced in large quantities. The use of flame retardant has grown dramatically over 

311 the past 30 years in response to concerns about the increasing use of flammable plastics and 

312 textiles. Many concerns surrounding these compounds focus on their persistence in the 

313 environment and bioaccumulation. While the flame retardants themselves are unlikely to form 

314 DBPs due to their inherent environmental persistence, effluent streams of the facilities that 

315 produce and use these compounds (i.e. textile mills) could be a possible source. 

316 ANALYSIS OF POTENTIAL IMPACT ON DRINKING WATER

317 Currently there are no standards for drinking water or receiving waters for bromide, since 

318 in its unreacted form, bromide has no known health effects associated with ingesting it. 

319 Drinking water utilities have not traditionally monitored for bromide in their sources, and in 

320 most cases, industries are not required to report levels of bromide discharged to receiving waters.

321 In order to determine the potential number of drinking water utilities that could be 

322 impacted by the bromide resulting from wet scrubber installations at coal fired plants, a number 

323 of databases and tools were used.
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324 According to the U. S. Energy Information Administration, there were 332 electric 

325 utilities that used coal from 2002 to 2011 (USEIA 2011). This number only includes the electric 

326 production for the public entities and not the independent power producers or the commercial 

327 and industrial sectors. These sectors operated an additional 257 coal fired units during 2011, 

328 although they are much smaller in general, than those owned by the electric utilities. 

329 Of the 332 public entities identified, 302 have NPDES permits. 

330 Using the latitude and longitude information provided in the NPDES permits for these 

331 plants, a map was created in ArcMap, as shown in Figure 5. Along with the latitude and 

332 longitude the database for these power plants also contains plant nameplate capacity (USEIA

333 2011), NPDES permit number (USEP 2013), HUC code (USEPA 2013), FGD type and install 

334 year (USEIA 2011) and current coal sulfur content (USEIA 2013c). This information was used 

335 to identify water bodies potentially at risk for bromide contamination.

336 As shown, most of the power plants using coal are east of the Mississippi River. They 

337 are typically located on or near a large surface water body. Also, a high density of coal-fired 

338 power plants is located on the borders of Ohio, West Virginia, Kentucky, and Indiana where the 

339 Ohio River is located. 

340 Out of the 302 coal-fired electric utility power plants with NPDES permits identified, 118 

341 had wet scrubber installations (shown in Figure 5, part A), 39 had dry scrubber installations and 

342 eight used a high sulfur content coal (>2%) which, as previously discussed are good candidates 

343 for a wet scrubber installation. 

344 SDWIS (Safe Drinking Water Information System) was then used to map community 

345 water systems (CWS) that use surface water. The SDWIS database contains information on all 

346 community surface drinking water treatment plants in the US including location, Public Water 
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347 System Identification (PWS ID) number, population served, and contact information. This 

348 database included 8,370 surface water treatment plants which serve a population larger than 500. 

349 The surface drinking water treatment plant database and the 118 coal-fired power plants 

350 with wet scrubbers were plotted in ArcMap, shown in Figure 5 part B with streams/canals, rivers, 

351 and water bodies layers. This was done to display power plants that could have bromide in their 

352 wastewater effluent. Then with the understanding of stream flow direction, NPDES HUC codes 

353 for the power plants, and visual confirmation of drinking water treatment plant locations, 96 

354 surface drinking water treatment plans were identified as being downstream from 57 wet 

355 scrubber coal-fired power plants. One power plant effluent could impact multiple water 

356 treatment plant intakes. These water treatment plants and power plants are shown in Figure 6. 

357 An example of how potentially impacted facilities were identified using the power plant 

358 and water treatment plant location databases is shown in Figure 7. Figure 7 includes locations of 

359 a power plant, rivers, streams, and drinking water treatment facilities using surface water. All of 

360 the facilities shown in Figure 7 use the same source whether it is influent (WTP) or effluent 

361 (power plant). 

362 Through SDWIS it was determined whether these 96 downstream utilities had a reported 

363 MCL violation of TTHM or HAA5. Out of the 96 water treatment plants identified, 25 had DBP 

364 MCL violations and 17 of those had violations occurred after wet scrubber installations. Of

365 those 17, six water treatment plants had violations occur within a year of the install. These 

366 numbers suggest that there may be a correlation between the installation of the wet scrubber and 

367 increased DBP formation at downstream water plants, although many factors impact the 

368 formation of DBPs. To determine if these increases could be due to power plant effluents, state

369 regulators and utility personnel at these water plants were contacted for further information.
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370 UTILITY IMPACTS BY COAL FIRED PLANTS

371 Personnel at fourteen utilities and eight states were contacted. Of those, some reported 

372 no increase in DBPs. Four drinking water utilities were identified, WTP A through D in Table 2, 

373 as having documented increases in brominated DBPs along with increased bromide in their 

374 source water believed to be from the wet scrubber installation at coal-fired power plants. All of 

375 these increases followed a wet scrubber installation at an upstream power treatment plant. The 

376 data from each of these four plants is described below.

377 Water Treatment Plant A

378 As shown in Table 2, WTP A has not had a DBP violation. But THM and HAA data 

379 indicated that increases in brominated DBPs were noted during the same time periods elevated 

380 bromide was noted in the source water. The increased bromide in the plant’s source water 

381 appears to have occurred shortly after the wet scrubber installation at the power plant in 2009. 

382 The TTHM compound impacted most from the increase in bromide in the source water 

383 was bromoform. Bromoform in the finished water increased by a factor of 10 to 20. Levels of 

384 bromodichloromethane, bromodichloromethane and bromochloroacetic also increased. Other 

385 water treatment plants in the area made similar observations, however they declined to provide 

386 these data. 

387 Water Treatment Plant B 

388 Two water treatment plants, WTP B and WTP C were identified in the NPDES permit of 

389 a coal fired power plant that installed a wet scrubber in 2008 were contacted. WTP B shared 

390 quarterly compliance data. WTP B did not have a violation but utility personnel stated that 

391 bromide was observed in their source water in 2008 and was not present before this time. In 

392 response to the elevated bromide levels, the utility took samples from the source water, went 
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393 several miles upstream and collected samples at each effluent water source. They concluded that 

394 the upstream power plant was the bromide source. 

395 WTP B uses free chlorine for disinfection but intends to switch to chloramines to avoid 

396 DBP exceedances. Figure 8 part A shows WTP B’s average quarterly TTHM speciation for all 

397 sampling locations over time. The black line on the figure represents the TTHM MCL level and 

398 the vertical red line shows the year that the upstream power plant installed a wet scrubber. For a 

399 TTHM MCL violation to occur the running annual average must exceed 80 μg/L. Exceeding the 

400 MCL for one quarter may not result in a violation if the last three quarters were far enough below 

401 the MCL to result in the average of the four quarters to be below the MCL. Prior to 2008, the 

402 year of the wet scrubber installation, WTP B had relatively low TTHM concentration made up of 

403 mostly chloroform. After the wet scrubber installation the TTHM not only increased but the 

404 speciation was dominated by brominated THMs. 

405 The speciation change is better illustrated when comparing two of the same quarters but 

406 from different years, one preceding the wet scrubber installation and one following. For WTP B 

407 the second and fourth quarters before and after the installation are shown in Figure 8 part B

408 where chloroform is shown in blue. Before the wet scrubber, 2008, less than 25 percent of the 

409 TTHM was from brominated compounds, after the installation more than 80 percent of the 

410 TTHM was from brominated compounds. 

411 Water Treatment Plant C

412 When WTP B started to monitor bromide they contacted WTP C. In response, WTP C 

413 also began to monitor bromide at their intake. WTP C is approximately eight miles from the 

414 power plant discharge location while WTP B is about 20 miles away from the source. As shown 

415 in Figure 9 part A, after the wet scrubber installation, the red line, the speciation changed and the 
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416 concentrations increased. Bromide monitoring data is also shown in Figure 9 part A. WTP C has 

417 had three quarters of THM violations. All violations occurred after the wet scrubber installation 

418 in 2008, one in 2009 and two in 2011. As shown in Figure 9 part B, for the same quarter before 

419 the scrubber installation the TTHM is almost entirely comprised of chloroform and for the 

420 quarters with violations, after the wet scrubber installation, over 90 percent of the TTHM is from 

421 brominated compounds. In response to the violations the utility initiated a flushing program in 

422 the distribution system and they have installed an aeration system to remove DBPs. 

423 Water Treatment Plant D

424 WTP D was identified using the power plant and water treatment plant location databases 

425 and is located downstream from a wet scrubber power plant’s discharge location. The upstream 

426 power plant had two wet scrubbers installed, one in 2006 and one in 2007, indicated by the red 

427 lines in Figure 10 part A. Although the change is not as dramatic as WTP B the majority of 

428 THM speciation is brominated after the wet scrubber installations. The change is more easily 

429 observed in Figure 10 part B, where brominated species make up less than 20 percent of TTHM 

430 before 2006, when the first wet scrubber was installed and more than 50 percent after 2007, 

431 when the second wet scrubber was installed. 

432 UTILITIES IMPACTS BY OTHER INDUSTRIES

433 Other potential sources of bromide such as hydraulic fracturing and textile production, 

434 have been reported. 

435 Wilson and VanBriesen (2012) reported bromide concentrations in excess of 500 μg/L 

436 during low stream flow periods in 2008 and 2009 on the Allegheny River. The authors correlated 

437 these increases with increased DBP violations. Between 2008 and 2011, 33 different Western 

438 Pennsylvania drinking water systems exceeded THM MCLs (Frazier and Murray 2011).
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439 States et al. (2012) reported during 2010, seven water treatment plants using the 

440 Allegheny River as a source had 19 to 110 μg/L TTHMs in their effluent with 12 to 55 percent of 

441 those from bromoform.

442 Water Treatment Plant E

443 WTP E was initially identified and contacted using the coal-fired power plant and surface 

444 water treatment plants database. Utility personnel contacted believe that hydraulic fracturing was 

445 the main cause for WTP E’s bromide and subsequent TTHM increase. Since 2008, WTP E’s 

446 source water had high TDS, and so was diluted with groundwater from backup wells. The utility

447 personnel stated that this occurred around the time that hydraulic fracturing began in that area of 

448 the country and they believe that fracturing has caused this change. Nearby plants in the area 

449 have also violated the TTHM MCLs since 2008. Another city that received its water from WTP 

450 E exceeded THMs in the water supply in May 2013.

451 Figure 11 part A shows the average quarterly TTHM speciation for all sampling 

452 locations for WTP E from 1999 to 2013, where each color represents a different compound that 

453 makes up TTHM and the black line represents the TTHM MCL. According to the utility, the 

454 hydraulic fracturing wastewater discharges in the area started in 2008. It is clear that the 

455 chlorinated portion (blue) decreases after 2008 and the brominated portion increases (all other 

456 colors). This comparison is better shown in Figure 11 part B, where the first column represents 

457 samples before hydraulic fracturing impacts and the second represents after. Before hydraulic 

458 fracturing the brominated compounds made up 50 percent or less of TTHM and after they made 

459 up more than 80 percent TTHM.

460 Water Treatment Plant F
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461 WTP F was identified through contacts made in the project. The WTP had a THM 

462 violation in August of 2012 that resulted in the utility calling state personnel. The state worked 

463 with two point sources, both textile mills located about 100 miles upstream where bromide was 

464 discharged from a chemical manufacturing process. This impact was initially noticed by the 

465 water treatment plant during the fourth quarter of 2011, which agrees with the TTHM rise above 

466 the TTHM MCL in the third quarter in 2011, shown in Figure12 part A. Also, the speciation 

467 shown in Figure 12 part B shows a shift from 30 percent to 80 percent brominated THMs before 

468 and after the textile mill impact, respectively. In response to the bromide levels, the WTP 

469 changed its treatment process. This included increasing the permanganate dose in their reservoir, 

470 moving their powdered activated carbon feed to allow for longer contact time, decreasing the 

471 chlorine dose used in pre-chlorination, and decreasing the chlorine dose in the distribution 

472 system. The state also worked with the textile mills to reduce their discharge.

473 POSSIBLE WAYS TO LIMIT BROMIDE IN SOURCE WATER

474 In order to limit the discharge of toxics to a receiving body, states must develop water 

475 quality standard as regulated by the Clean Water Act. Water quality standards are provisions of 

476 State or Federal law which consist of a designated use or uses for the receiving waters and water 

477 quality criteria for such waters based upon such uses.

478 The USEPA website describes the methods that can be used by states to develop these 

479 standards. http://water.epa.gov/scitech/swguidance/standards/wqsregs.cfm

480 As discussed previously, some states have attempted to limit the discharge of bromide 

481 through NPDES permits. But, since bromide has not been defined as a “toxic pollutant” 

482 according to the list contained in the CWA (section 307.a), or as a “pollutant” it has been 

483 difficult to include bromide limits in discharge permits. However, as the CWA was designed to 
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484 “protect the designated use,” states may be able to develop a water quality standard for bromide 

485 that recognizes that the transformation of bromide within the drinking water plant into by486 products with human health implications justifies limiting its discharge into a receiving water.

487 While some states are not able to get effluent concentration restrictions, some have been 

488 able to write in effluent monitoring requirements power plant’s National Pollutant Discharge 

489 Elimination System (NPDES) permits. For example, a power plant in North Carolina that 

490 installed a wet scrubber in 2008 is required by its NPDES permit to take monthly grab samples 

491 that are analyzed for bromide. The permit also requires that the plant submit a semi-annual 

492 status report on the effort they undertake to reduce bromide at the source of downstream water 

493 treatment plants. In the event of a TTHM MCL violation at two named water treatment plants 

494 that are located downstream or any wholesale customers of those systems, the power plant is 

495 required within 14 days of the request to provide the latest available bromide monitoring data so 

496 that it can be incorporated into required public notices issued by the water treatment plant(s).

497 CONCLUSIONS

498 With new bromide sources being introduced into drinking water sources it is important 

499 for the downstream impacts to be considered. Water utilities need to be made aware of the 

500 potential impact of bromide on their distribution system TTHMs and HAAs. This report 

501 highlighted a number of occurrences of utilities exceeding MCLs because of the shift to 

502 brominated species. However, it is suspected that many utilities have experienced elevated 

503 levels of DBPs without MCL exceedances but are unaware of the cause for this change.

504 Further, State agencies should closely evaluate the discharge permits of industries that 

505 use bromide in their processes such as coal fire plants and determine if monitoring and bromide 

506 limits are appropriate. Because it is so difficult for water plants to remove bromide from their 
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507 source water, the best course of action will be to prevent bromide from entering the source of any 

508 drinking water plant.

509 REFERENCES

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511 Water and Impacts on DBP Formation. AWWA Research Foundation and American 

512 Water Works Association, Denver, CO, Project #825.

513

514 AWWA. 2004. Formal Comments of the American Water Works Association on the Stage 2 

515 Disinfectants and Disinfection By-Products Proposed Rule, Water Docket OW-2002-

516 0043. Washington, DC: AWWA.

517

518 Benson, S.A., Holmes, M.J., McCollor, D.P., Mackenzie, J.M., Crocker, C.R., Kong, L., 

519 Galbreath, K.C., Dombrowski, K., Richardson, C. 2007. Large-Scale Mercury Control 

520 Technology Testing for Lignite-Fired Utilities – Oxidation Systems for Wet FGD. US 

521 DOE, NETL. 2007-EERC-03-12.

522

523 Blythe, G., Richardson, C., Rhudy, R. 2002. Pilot Evaluation of the Catalytic Oxidation of 

524 Mercury for enhanced Removal in Wet FGD Systems. In Proceedings of Air Quality III: 

525 Mercury, Trace Elements and Particulate Matter Conference, Arlington, VA, September 

526 9-12, 2002. Energy and Environmental Research Center, University of Dakota, Grand 

527 Fork, North Dakota, September 2002.

528

529 Bowen, B.H., Irwin, M.W. October 2008. Coal Characteristics: Center for Coal Technology 

530 Research Basics Facts File #8. The Energy Center at Discover Park, Perdue University. 

531 http://www.purdue.edu/discoverypark/energy/assets/pdfs/cctr/outreach/Basics8-

532 CoalCharacteristics-Oct08.pdf

533

534 Bowen, H.J.M. 1979. Environmental Chemistry of Elements. London: Academic Press. 

535

536 Buschmann, J., Lindau, L., Vosteen, B.W. 2005. The KNX Coal Additive Technology: A Simple 

537 Solution for Mercury Emissions Control. ALSTOM Power Inc. http://www.vosteen538 consulting.de/downloads/2005_12_Vosteen_Consulting_KNX_TM_Coal_Additive_Tech

539 nology_PowerGen_USA.pdf

540

541 Bustard, J., Renninger, S., Chang, R., Miller, R., Monroe, L., Sjostrom, S. 2003. Results of 

542 Activated Carbon Injection for Mercury Control Upstream of COHPAC Fabric Filter. 

543 Presented at the A&WMA/EPA/DOE/EPRI Combined Power Plant Air Pollutant Control 

544 Mega Symposium, Washington, DC, May 19-22, 2003.

545

546 Cantor, K.P., Villanueva, C.M., Silverman, D.T., Figueroa, J.D., Real, F.S., Garcia-Closas, M., 

547 Malats, N., Chanock, S., Yeager, M., Tardon, A., Garcia-Closas, R., Serra, C., Carrato, 

548 A., Castano-Vinyals G., Samanic, C., Rothman, N., and Kogevinas, M. 2010. 
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549 Polymorphisms in GSTT21, GSTZ1, and CYP2E1, disinfection by-products, and risk of 

550 bladder cancer in Spain. Environmental Health Perspective, 118, 1545-1550.

551

552 Chang, R. et al. 2008. Near and Long Term Options for Controlling Mercury Emissions from 

553 Power Plants. Proceedings of the Power Plant Air Pollutant Control “Mega” Symposium, 

554 Baltimore, MD, August 25-28, 2008. 

555

556 Environmental Law Clinic, University of Pittsburgh School of Law. 2009. Wastewater 

557 Treatment Facilities. Clean Water Action, 2009, July 15. http://www.pennfuture.org/

558 UserFiles/File/Marcellus_WaterTreatment_20090715.xls

559

560 Ferrar et al. 2013. Assessment of Effluent Contaminants from Three Facilities Discharging 

561 Marcellus Shale Wastewater to Surface Waters in Pennsylvania. Environ. Sci. Technol., 

562 47, 3472-3481.

563

564 Frazier, R.R., Murray, A. 2011. Salts from drilling, a drinking water danger, still showing up in 

565 rivers. The Allegheny Front. December 2, 2011. 

566

567 Greune, A., Knappe, D. (2013.) Bromide Occurrence in North Carolina Surface Waters. NC 

568 State University.

569

570 Hayes, T. 2009. Sampling and Analysis of Water Streams Associated with the Development of 

571 Marcellus Shale Gas; Report for the Marcellus Shale Coalition; Gas Technology Institute

572

573 Jolley, R. 1975. Chlorine-containing organic constituents in chlorinated effluents. Jour WPCF. 

574 47:3:601.

575

576 Kellie, S., Cao, Y., Duan, Y., Li, L., Chu, P., Mehta, A., Carty, R., Riley, J.T., Pan, W.P. 2005. 

577 Factors Affecting Mercury Speciation in a 100-MW Coal-Fired Boiler with Low-NOx 

578 Burners. Energy Fuels, 19:3:800-806.

579

580 Mcilvaine Company, 2012. Big Market for Chemicals to Capture Mercury. 

581 www.pollutionsolutions-online.com

582

583 McGuire, M., McLain, J., Obelensky, A. 2002. Information Collection Rule Data Analysis. 

584 WaterRF, Denver, CO.

585

586 Robart, C. J. 2012. Water Management Economics in the Development and Production of Shale 

587 Resources; International Association for Energy Economics; http://www.google.com/

588 url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&ved=0CFYQFjAC&url=http%3A%2F

589 %2Fwww.iaee.org%2Fen%2Fpublications%2Fnewsletterdl.aspx%3Fid%3D157&ei=KX

590 18T6fiKMX00gGRqN3oCw&usg=AFQjCNE1P6_9r6UvkXfecb8RQPRMMI5jpg&sig2

591 =ftRnZeUjOamktVCa8pK5gg.

592

593 States, S., Cyprych, G., Stoner, M., Wyndra, F., Kuchta, J., Casson, L., Monnell, J., 2012. 

594 Bromide in the Allegheny River and THMs in Pittsburgh Drinking Water: A Link with 
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595 Marcellus Shale Drilling. Ohio AWWA; http://www.ohiowater.org/oawwa/oawwa/

596 state%20conventions/ARCHIVES/2012/Presentations/Bromide%20in%20the%20Allegh

597 eny%20River%20and%20THMs.pdf

598

599 US DOE. 2012. Annual Energy Outlook 2012: Early Release Overview; Energy Information 

600 Administration. Energy Information Agency; http://www.eia.gov/forecasts/aeo/er/pdf/

601 0383er%282012%29.pdf.

602

603 US EIA. 2011. Form EIA-860. US DOE, Washington, DC. http://www.eia.gov/electricity/

604 data/eia860/.

605

606 US EIA. 2013a. How Much Coal, Natural Gas, or Petroleum Is Used to Generate a Kilowatt607 hour of Electricity? Web. http://www.eia.gov/tools/faqs/faq.cfm?id=667&t=2.

608

609 US EIA. 2013b. 2012 Brief: Coal Prices and Production in Most Basins Down in 2012. U.S. 

610 Energy Information Administration. www.eia.gov/todayinenergy/detail.cfm?id=9570

611

612 US EIA. 2013c. Form EIA-923. US DOE, Washington, DC. http://www.eia.gov/

613 electricity/data/eia923/.US EPA. 2003. Air Pollution Control Technology Fact Sheet: 

614 Flue Gas Desulfurization (FGD) – Wet, Spray Dry, and Dry Scrubbers. Washington, DC: 

615 US EPA.

616

617 USEPA. 2006. Stage 2 Disinfectants and Disinfection Byproducts Rule: National Primary and 

618 Secondary Drinking Water Regulations: Final Rule. Federal Register 71:2:388-493, 

619 January 4, 2006.

620

621 USEPA. 2011. Regulatory Impact Analysis for the Final Mercury and Air Toxics Standards 

622 (EPA-452/R-11-011). Washington, DC: US EPA.

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624 USEPA . 2012. National Emissions Standards for Hazardous Air Pollutants from Coal- and Oil625 fired Electrical Generating Units (40 CFR 60 and 63). Federal Register. 77:32:9304-

626 9513.

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628 USEPA. 2013. Facility Registry Service (FRS) Query. US EPA, Washington, DC. 

629 http://www.epa.gov/enviro/html/fii/fii_query_java.html.

630

631 Weinberg, H.S., Krasner, S.W., Richardson, S.D., Thruston, A.D. 2002. The Occurrence of 

632 Disinfection By-Products (DBPs) of Health Concern in Drinking Water: Results of a 

633 Nationwide DBP Occurrence Study. National Exposure Research Laboratory. Office of 

634 Research and Development, United States Environmental Protection Agency, Athens, 

635 GA. EPA/600/R-02/068

636

637 Wilson, J.M., VanBriesen, J.M. 2012. Oil and Gas Produced Water Management and Surface 

638 Drinking Water Sources in Pennsylvania. Environmental Practice, 14 (4) 288-300. 

639

640
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Table 1

Bromide Concentrations in CWTs and POTWs in PA Treating Marcellus Shale Wastewater

Name

Treatment 

facility type

Br concentration 

(μg/L) a,b Date Plant flow 

(gal/day) c

Receiving 

watershed c minimum maximum minimum maximum

PA Brine Josephine Facility CWT 601,000 8,290,000 5/25/2011 12/21/2011 155,000 Allegheny

PA Brine Franklin Facility CWT 364,000 770,000 8/2/2011 5/9/2011 300,000 Allegheny

Minard Oil Dent Treatment 

Facility CWT 606,000 657,000 10/6/2011 2/9/2012 16,000 Monongahela

Brockway Sewer Authority POTW 2,320 19,200 12/7/2011 11/21/2011 1,500,000 Allegheny

Ridgway Borough POTW 2,880 11,500 9/8/2011 7/21/2011 2,20,000 Allegheny

City of McKeeport POTW 119 600 10/20/2010 10/19/2010 11,500,000 Monongahela

Franklin TWP of Greene County POTW <0.016 20,910 11/7/2011 11/10/2010 1,250,000 Monongahela

a US EPA.2013. Key Documents About Mid-Atlantic Oil and Gas Extraction. http://www.epa.gov/region03/marcellus_shale

b Ferrar et al. 2013. Assessment of Effluent Contaminants from Three Facilities Discharging Marcellus Shale Wastewater to Surface Waters in Pennsylvania. Environ. Sci. Technol., 47, 3472-3481.

c Environmental Law Clinic, University of Pittsburgh School of Law. 2009. Wastewater Treatment Facilities. Clean Water Action, 2009, July 15. 

http://www.pennfuture.org/UserFiles/File/Marcellus_WaterTreatment_20090715.xls
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Table 2

Water Treatment Plants impacted by bromide sources with the population they serve, the 

wet scrubber installation years of the upstream wet scrubbers, and the years the water 

treatment plant had TTHM or HAA5 MCL violations.

Water 

treatment 

plant

Bromide 

source

Population 

served

Wet scrubber 

installation year

TTHM 

violation 

year

HAA5

violation year

A Power plant 227,000 2006, 2007, 2009 - -

B Power plant 16,000 2008 - -

C Power plant 3,000 2008 2008, 2009 -

D Power plant 24,000 2006, 2007 - 2003

E

Shale gas 

wastewater 

discharge

22,000 - 2008, 2009 -

F Textile mill 18,000 - 2012 -
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Figure 1 Location of US Power Plants impacted by new air quality regulations (US EPA 2011)
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Figure 2 Measured bromide concentration in the FGD liquor with respect to bromide 

concentration in coal (Benson et al. 2007)

Figure 3 Projected State-by-State mercury (Hg) emissions from US Coal-Fired Power 

Plants with and without improvements in response to MATS requirements 

(USEPA 2011)
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Figure 4 Projected increase in US Coal-Fired Wet FGD Capacity (Miller et al. 2006)
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a) Coal-fired power plants with NPDES Permits (302) and those with wet 

scrubbers (118) in the U.S.

b) Surface water treatment plants and coal-fired power plants with and without 

wet scrubbers

Figure 5 Locations of surface water plants and coal fired power plants
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Figure 6 Coal-fired power plants with wet scrubbers and downstream surface drinking water treatment plants Note, there 

are 96 WTPs identified with several hidden in the map
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Figure 7 A coal-fired power plant and five downstream surface water treatment plants 

for drinking water
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a) Average quarterly TTHM concentrations for WTP B from Quarter 2 of 2006 to Quarter 3 of 

2013

Before Upstream Wet Scrubber 

Installation

After Upstream Wet Scrubber 

Installation

b) THM Speciation for WTP B for the same quarters preceding and following the wet scrubber 

installation year, 2008

Figure 8 THM Data from Water Plant B

0.0000

0.0200

0.0400

0.0600

0.0800

0.1000

0.1200

0.1400

5/3/20068/1/2006

11/8/2006

2/6/20075/1/20078/7/2007

11/20/2007

2/12/20085/20/20088/12/2008

11/18/2008

2/24/20095/12/20098/18/200911/9/20092/17/20105/12/20108/18/201011/1/2010

2/1/20115/2/20118/1/2011

11/1/2011

2/1/20124/2/20127/3/20128/2/2012

11/28/2012

2/5/20134/2/20137/1/2013

THM (mg/L)

Chloroform Bromoform Bromodichloromethane

Dibromochloromethane TTHM MCL

Wet Scrubber Installation

Chloroform Bromoform Bromodichloromethane Dibromochloromethane

Q4 2006 Q4 2012

Q2 2007 Q2 2013
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a) TTHM concentrations for WTP C from Quarter 1 of 2006 to Quarter 4 of 2012

Before Upstream Wet Scrubber 

Installation

After Upstream Wet Scrubber 

Installation

b) THM Speciation for WTP C for the same quarters preceding and following the wet 

scrubber installation year, 2008

Figure 9 THM Data from Water Plant C

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.0000

0.0200

0.0400

0.0600

0.0800

0.1000

0.1200

0.1400

0.1600

0.1800

02/23/0609/20/0602/14/0709/19/0702/20/0809/18/0802/18/0909/24/0902/25/1009/08/1003/10/1109/07/11

7/31/20128/13/20128/28/20129/10/20129/24/201210/8/2012

10/23/2012

11/5/2012

11/19/2012

12/3/2012

12/17/2012

Bromide (mg/L)

THM (mg/L)

Chloroform Bromoform Bromodichloromethane

Dibromochloromethane TTHM MCL Bromide

Wet Scrubber Installation

Chloroform Bromoform Bromodichloromethane Dibromochloromethane

Q2 2008 Q2 2011

Q3 2006 Q3 2011
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a) Average quarterly TTHM concentrations for WTP D from Quarter 2 2005 to Quarter 4 

2012

Before Upstream Wet Scrubber 

Installation

After Upstream Wet Scrubber 

Installation

b) THM speciation for WTP D for the same quarters preceding and following the wet scrubber 

installation year, 2006 and 2007

Figure 10 THM Data from Water Plant D

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

THM (mg/L)

Chloroform Bromoform Bromodichloromethane

Chlorodibromomethane TTHM MCL

Wet Scrubber Installations

Chloroform Bromoform Bromodichloromethane Dibromochloromethane

Q1 2005 Q1 2008

Q4 2005 Q4 2008
EE&T, INC. 10

a)Average quarterly TTHM concentrations for WTP E from Quarter 2 1999 to Quarter 3 2013

Before Hydraulic Fracturing Activity After Hydraulic Fracturing Activity

b) THM Speciation for WTP E for the same quarters preceding and following hydraulic fracturing 

activity

Figure11. THM Data from Water Plant E

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0.18

5/4/1999

12/7/19994/30/2000

12/13/2000

4/4/2001

12/5/20014/24/2002

12/10/2002

4/2/2003

12/11/2003

4/6/2004

12/9/2004

4/6/2005

12/7/2005

4/6/2006

12/6/20064/11/2007

12/11/2007

4/16/20088/28/20081/11/2009

7/8/2009

1/14/20107/14/20101/11/20117/13/20111/18/2012

7/9/20121/9/20137/9/2013

THM (mg/L)

Chloroform Bromoform Bromodichloromethane

Dibromochloromethane TTHM MCL

Chloroform Bromoform Bromodichloromethane Dibromochloromethane

Q3 2006 Q3 2008

Q1 2007 Q1 2009
EE&T, INC. 11

a) Average quarterly TTHM concentrations for WTP F from Quarter 1 2007 to Quarter 3 2012

Before Textile Mill Impacts After Textile Mill Impacts

b) THM Speciation for WTP F for the same quarters preceding and following the wet scrubber 

installation year, 2006 and 2007

Figure12 THM Data from Water Plant F

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0.1

2/21/20075/24/20078/28/2007

10/16/2007

1/23/20084/23/20087/22/2008

10/22/2008

1/21/20094/22/20097/22/200911/2/20093/16/20104/21/20107/22/2010

10/20/2010

1/19/20114/20/20117/21/2011

10/20/2011

1/18/20125/16/20128/16/2012

TTHM (mg/L)

Chloroform Bromoform Bromodichloromethane

Dibromochloromethane TTHM MCL

TTHM Q2 2007

Chloroform

Bromoform

TTHM Q2 2012

TTHM Q3 2009 TTHM Q3 2012