Update on USEPA's drinking water regulations

Pontius, Frederick W.

doi:10.1002/j.1551-8833.2003.tb10314.x

Cited by 28 publications

(17 citation statements)

References 11 publications

(13 reference statements)

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“…The proposed stage 2 disinfection and DBP regulations (15,16) will only make this task more difficult. Although chlorine disinfection remains quite popular in the United States (6,7), many utilities now use combinations of chlorine and chloramines to avoid excessive trihalomethane (THM) and haloacetic acid formation.…”

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confidence: 99%

Cometabolism of Trihalomethanes by Nitrosomonas europaea

Wahman

Katz

Speitel

2005

Appl Environ Microbiol

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. Degradation kinetics were best described by a reductant model that accounted for two limiting reactants, THMs and ammonia-nitrogen (NH 3 -N). A decrease in the temperature resulted in a decrease in both ammonia and THM degradation rates with ammonia rates affected to a greater extent than THM degradation rates. Similarly to the THM degradation rates, product toxicity, measured by transformation capacity (T c ), increased with increasing THM bromine substitution. Because both the rate constants and product toxicities increase with increasing THM bromine substitution, a water's THM speciation will be an important consideration for process implementation during drinking water treatment. Even though a given water sample may be kinetically favored based on THM speciation, the resulting THM product toxicity may not allow stable treatment process performance.Balancing the competing goals of disinfection and disinfection by-product (DBP) regulations is a challenge for many drinking water utilities. The proposed stage 2 disinfection and DBP regulations (15, 16) will only make this task more difficult. Although chlorine disinfection remains quite popular in the United States (6, 7), many utilities now use combinations of chlorine and chloramines to avoid excessive trihalomethane (THM) and haloacetic acid formation. A typical treatment scheme consists of an initial period of chlorination to help achieve disinfection goals followed by quenching with ammonia at some point in the treatment train to meet DBP goals through the lower DBP formation rates associated with chloramines. Nevertheless, significant formation of THMs and haloacetic acids can occur within treatment plants even during relatively short periods of chlorination (24, 28). Therefore, approaches for minimizing the formation of these DBPs or for removing the DBPs within treatment plants are potentially of much practical value.Much effort over the past two decades has gone into approaches for minimizing DBP formation through modification of disinfection practices and removal of precursor materials (23), while comparatively little effort has been expended on approaches for removing DBPs formed in treatment plants before finished water is sent into distribution systems. Very early on, both technological and philosophical problems with the removal of THMs through activated carbon adsorption and air stripping were identified (28), and approaches for removing DBPs after formation have been largely ignored since that time. Recent developments in biological treatment, however, strongly suggest that revisiting treatment processes for THM removal is worthwhile.No evidence indicates that THMs can support microbial growth. Considerable evidence is available, however, for cometabolism of chloroform, or trichloromethane (TCM), by bacteria growing on other chemicals (2, 5, 9). Of particular interest is the observation that nitrifying bacteria can cometabolize chloroform at a reasonable rate (0.03 to 0.1 liter/mg/ day). The premise of this research is that THM removal should b...

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confidence: 99%

Cometabolism of Trihalomethanes by Nitrosomonas europaea

Wahman

Katz

Speitel

2005

Appl Environ Microbiol

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“…Tables listing current drinking water standards and their applicability have been presented in a previous article (Pontius, 2003). Currently, National Primary Drinking Water Regulations (NPDWRs) are set for 92 contaminants.…”

Section: Us Drinking Water Regulations Are At a Crossroadsmentioning

confidence: 99%

Drinking Water Contaminant Regulation: —Where are We Heading?

Pontius¹

2004

Journal AWWA

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Since the US Environmental Protection Agency (USEPA) enacted the Safe Drinking Water Act (SDWA) in 1974, an increasingly complex series of rulemakings has transformed the US drinking water regulatory program into a labyrinth of requirements supported by a vast administrative superstructure. Furthermore, with each amendment of the SDWA, the paradigm applied to the regulation of drinking water contaminants has shifted. The financial and personnel demands imposed by implementation and compliance with existing and upcoming rules have strained the limited resources of water utilities, state agencies, and USEPA itself. In addition to summarizing the current regulatory program, this article delineates the patchwork quilt of requirements specified in the Stage 2 Disfectants/Disinfection Byproducts Rule and other upcoming regulations.

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“…Sources, Quantities, and Transport. The final EPA Radon Rule was the subject of Pontius (2003) annual update on USEPA s drinking water regulations.…”

Section: Radioactive Metalsmentioning

confidence: 99%

Groundwater Quality

Lange¹,

Lange²

2004

Water Environment Research

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This review covers studies related to groundwater quality and has been arranged by contaminant type. For each contaminant the quantity, fate and transport, remediation measures, and models published over the past year are presented. FLOWA methodology for stochastic management of groundwater flow and quality was presented by Bakr et al (2003) using coupled flow and mass transport equations. Using a multi-objective formulation of the management problem and analysis of its results, it was possible to identify an appropriate remediation scheme. A mathematical model for solute transport, using a laplace transform power series, was used to describe solute transport in a convergent flow field with scale-dependent dispersion (Chen et al, 2003a). The model results showed good agreement with field data. Woods et al (2003) showed that numerical error in groundwater transport models could lead to quantitative and qualitative changes in behavior. The authors confirmed this finding by showing 2190 the Elder problem to be extremely sensitive to the simulation method used. Nonreactive transport at the boarder of various asymmetrical cavities was modeled by Selvadurai (2003). Analytical results were developed for time-and spacedependent distribution of contaminant concentration in porous media, which can also exhibit natural attenuation.A block-effective macrodispersion model was used to simulate transport in heterogeneous aquifers (Rubin et al, 2003). The closed-form analytical results were attained very quickly. Das and Nassehi (2003) modeled contaminant mobility in the subsurface domains with multiple free/porous interfaces. The authors attempted to remove the limitations of previous mathematical models by imposing multiple pervious boundaries. The effects local-scale heterogeneity and non-linear, kinetically limited sorption phenomena on contaminant transport in porous media was discussed by Johnson et al (2003a). The results indicated that local-scale physical heterogeneity controlled the non-ideal transport behavior of trichloroethene and non-ideal sorption was of secondary importance. The flow behavior of liquid carbon tetrachloride in unsaturated heterogeneous porous media was studied by Oostrom et al (2003). The results indicate that nonspreading behavior of NAPLs should be implemented in simulators to account for the formation of residual saturations. A dependence of DNALP behavior on saturation history was demonstrated by Gerhard and Kueper (2003) using laboratory scale testing. Laboratory and numerical modeling investigations of flow and transport near a seepage face boundary was conducted by Simpson et al (2003a). The 2191 authors concluded that the use of the Dupuit approximations might introduce error into the analysis of localized solute transport near the seepage face.Anderson applied an approximation that replaced the leaky boundary with an equivalent layer that had a one-dimensional resistance to flow. The solution compared favorably with the commonly utilized Dupuit approximation.A model for unsaturated flow...

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Update on USEPA's drinking water regulations

Cited by 28 publications

References 11 publications

Cometabolism of Trihalomethanes by Nitrosomonas europaea

Cometabolism of Trihalomethanes by Nitrosomonas europaea

Drinking Water Contaminant Regulation: —Where are We Heading?

Groundwater Quality

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