EPA Signs LT2, Stage 2 DBP Rules

Promulgation of the Long Term 2 Enhanced Surface Water Treatment Rule (LT2) and the Stage 2 Disinfection Byproducts Rule (Stage 2 DBP) may require costly changes...

Promulgation of the Long Term 2 Enhanced Surface Water Treatment Rule (LT2) and the Stage 2 Disinfection Byproducts Rule (Stage 2 DBP) may require costly changes in treatment systems at some water utilities - a fact that concerns utilities but means new business for some equipment companies.

“Clean drinking water is a key ingredient to keeping people healthy and our economy strong,” said EPA Administrator Stephen L. Johnson. “Over the past seven years EPA has worked collaboratively with stakeholders to develop regulations that will provide a balance between the need to disinfect drinking water and protect citizens from potentially harmful contaminants.”

Finalizing the two rules represents the last phase of a congressionally required rulemaking strategy under the 1996 Amendments to the Safe Drinking Water Act, Johnson said.

The LT2 is designed to reduce the risk of disease-causing microorganisms from entering water supplies and Stage 2 DBP will require water systems to limit the amount of potentially harmful “disinfection byproducts” (DBPs) that end up in drinking water.

The rules were proposed in August 2003 and were developed from consensus recommendations from a federal advisory committee comprised of state and local governments, tribes, environmental, public health and water industry groups.

The American Water Works Association (AWWA) was a participant on a diverse federal advisory committee that provided input during the rule’s development.

EPA’s signing off on the rules “represents the latest step in an extensive stakeholder-based rulemaking process,” said Jack Hoffbuhr, executive director of AWWA.

“The drinking water community is committed to providing high-quality water that maximizes public health protection and minimizes potential health risks. As part of that ongoing commitment, we will continue to support the development of promising new treatment and monitoring technologies. We will also support research into potential health effects associated with contaminants like those addressed in these rules.”

At the same time, some in the utility industry are worried about the costs associated with the new rules.

“These rules may require dramatic treatment changes at significant costs in some communities. In small communities, these new costs will sometimes be borne by a small pool of ratepayers,” Hoffbuhr said.

Calgon Carbon Corp. is one company that expects the rules to open up new markets in the United States - generating an estimated $750 million over the next decade. The company’s ultraviolet light disinfection system for treating water fits the EPA’s new guidelines for destroying the Crypto.

“We’ve been waiting for this (final rules) for a long time,” said Calgon Carbon spokesman Gail Gerono, who was quoted in an article published by the Pittsburgh Tribune-Review.

Long-Term 2 Rule

The LT2 rule will apply to all public water systems that use surface water or ground water under the direct influence of surface water.

Under the LT2ESWTR, systems will monitor their water sources to determine treatment requirements. This monitoring includes an initial two years of monthly sampling for Cryptosporidium. To reduce monitoring costs, small filtered water systems will first monitor for E. coli - bacterium which is less expensive to analyze than Cryptosporidium - and will monitor for Cryptosporidium only if their E. coli results exceed specified concentration levels.

Monitoring starting dates are staggered by system size, with smaller systems beginning monitoring after larger systems. Systems must conduct a second round of monitoring six years after completing the initial round to determine if source water conditions have changed significantly. Systems may use (grandfather) previously collected data in lieu of conducting new monitoring, and systems are not required to monitor if they provide the maximum level of treatment required under the rule.

Filtered water systems will be classified in one of four treatment categories (bins) based on their monitoring results. The majority of systems will be classified in the lowest treatment bin, which carries no additional treatment requirements. Systems classified in higher treatment bins must provide 90 to 99.7 percent (1.0 to 2.5-log) additional treatment for Cryptosporidium. Systems will select from a wide range of treatment and management strategies in the “microbial toolbox” to meet their additional treatment requirements.

All unfiltered water systems must provide at least 99 or 99.9 percent (2 or 3-log) inactivation of Cryptosporidium, depending on the results of their monitoring. These Cryptosporidium treatment requirements reflect consensus recommendations of the Stage 2 Microbial and Disinfection Byproducts Federal Advisory Committee.

Systems that store treated water in open reservoirs must either cover the reservoir or treat the reservoir discharge to inactivate 4-log virus, 3-log Giardia lamblia, and 2-log Cryptosporidium. These requirements are necessary to protect against the contamination of water that occurs in open reservoirs. In addition, systems must review their current level of microbial treatment before making a significant change in their disinfection practice. This review will assist systems in maintaining protection against microbial pathogens as they take steps to reduce the formation of disinfection byproducts under the Stage 2 Disinfection Byproducts Rule.

Stage 2 DBP

Under the Stage 2 DBPR, systems will conduct an evaluation of their distribution systems, known as an Initial Distribution System Evaluation (IDSE), to identify the locations with high disinfection byproduct concentrations. These locations will then be used by the systems as the sampling sites for Stage 2 DBPR compliance monitoring.

Compliance with the maximum contaminant levels for two groups of disinfection byproducts (TTHM and HAA5) will be calculated for each monitoring location in the distribution system. This approach, referred to as the locational running annual average (LRAA), differs from current requirements, which determine compliance by calculating the running annual average of samples from all monitoring locations across the system.

The Stage 2 DBPR also requires each system to determine if they have exceeded an operational evaluation level, which is identified using their compliance monitoring results. The operational evaluation level provides an early warning of possible future MCL violations, which allows the system to take proactive steps to remain in compliance. A system that exceeds an operational evaluation level is required to review their operational practices and submit a report to their state that identifies actions that may be taken to mitigate future high DBP levels, particularly those that may jeopardize their compliance with the DBP MCLs.

The final rules will both be published in the Federal Register in January. Pre-publication copies and additional information can be found on the EPA web site at: http://www.epa.gov/safewater/disinfection/ WW

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