Streamline - Winter 2012 - (Page 15)
Chloramines in Question –
BY DONNA J. LAWSON, WASTEWATER TECH II
Controversy Stirs in Central Virginia
It was during Stage 2 that many water plant facilities began looking at chloramines as an alternative to chlorine as their primary disinfectant, to help reduce their disinfection byproducts.
The Stage 1 Disinfection ByProducts Rule (1 DBPR) and the Interim Enhanced Surface Water Treatment Rule (Dec. 1998) were developed in response from congressional amendments in 1996 to the Safe Drinking Water Act (SDWA). The SDWA required EPA to develop rules to balance the risks between microbial pathogens and disinfection byproducts (DBPS). A link between the disinfection of potable water, which initially saved lives in preventing typhoid and cholera epidemics, was found to increase bladder cancer and reproductive effects in humans. Public water facilities began monitoring for regulated contaminants, namely Total Trihalomethanes (TTHM) and 5 Haloaectic Acids (HAA5) with an MCL of 0.080 mg/L and 0.060 mg/L respectively. Further revision in 2001 brought forth the Stage 2 Disinfection ByProduct Rule (2 DBPR), which became effective in Jan. 2006. Stage 2 required stricter monitoring schedules, running averages and an evaluation of the distribution system (using longest water retention time). System compliance was scheduled according to population served: more sampling required of larger systems and a shorter time frame of compliance. All systems must be in compliance by Oct. 1, 2013, or have permission from their individual state for making capital improvements to do so. It was during Stage 2 that many water plant facilities began looking at chloramines as an alternative to chlorine as their primary disinfectant, to help reduce their disinfection byproducts. Since groundwater has little to no organics, smaller systems that use wells or groundwater under surface influence often met the 40-30 waiver. Thus they could reduce the required monitoring schedule in the distribution system for TTHMs and HAA5s to once per year in the hottest quarter. Many larger systems tend to use surface water, such as rivers and lakes, and depending upon the raw water quality were not able to easily meet the new running average for TTHMs and HAA5s. Systems began rigorous flushing programs, increasing water supply tank turnover, decreasing chlorine residual in the distribution system, and even eliminating predisinfection before filtration wherever possible. In the scramble to meet the compliance guidelines, facilities were bombarded by new technologies, methods and chemicals to reduce the production of the disinfection byproducts being formed from natural organics in their source water and the disinfection agent they were adding to make potable water for their customers. Newly engineered resins were introduced that promised to remove organic material. Systems began adding potassium permanganate at the start of treatment. Granular activated carbon (GAC) was also gaining popularity, not only for taste and odor removal, but also for the ability to absorb organic material. It was at this time that EPA, local primacy agencies and chemical suppliers recommended chloramines to utilities that had not been able to meet or reduce their newly regulated disinfection byproducts by other methods, and were still using chlorine as their primary disinfectant. After a few scary mishaps of systems reporting feline urine odors in homes resulting from formaldehyde with newly installed carpets during the transition of chlorine to chloramines, all seemed right with the world again. That is until reports of skin rashes, fish kills, pipe corrosion and even more toxic and mutagenic disinfection byproducts began.
Chloramines are formed by the addition of chlorine (Cl2) to ammonia (NH3). Chloramine (NH2Cl) is a highly unstable compound in concentrated form. Pure NH2Cl decomposes
Table of Contents for the Digital Edition of Streamline - Winter 2012
From the President
From the Executive Director
Groundwater in the Karst Landscape
There’s a Chill in the Air!
Chloramines in Question
Preventative (Planned) Maintenance II
What About Water Rates?
How to Get a Great Rate Analyst
Throwing My Loop
Do You Know What Your VRWA Benefi ts Are?
Welcoming New Members
Board Of Directors
Index To Advertisers/Ad.com
Streamline - Winter 2012