EPA Proposal Would Update Total Coliform Rule

The U.S. EPA is expected to issue a new rule revising the existing Total Coliform Rule after a comment period ending in October. The proposed rule is highlighted in the current on-Line issue of Ultrapure Water that is now available.

LITTLETON, Colo.-The U.S. Environmental Protection Agency (EPA) has issued a new proposed revised Total Coliform Rule (RTCR). This proposed rule is expected to take effect after an Oct. 13 comment period deadline, and the subsequent final rule publication in the Federal Register.

The lead article in the October on-line issue of ULTRAPURE WATER highlights some of the recommended changes in the proposed rule that would impact drinking water treatment and water treatment systems (WTSs). The rule would also impact industrial facilities that treat their own drinking water supplies instead of relying on an outside WTS. Examples would be power or industrial plants located in remote areas.

The proposed rule comes from recommendations made by an advisory committee that reviewed the 1989 Total Coliform Rule (TCR) that was implemented under the Safe Drinking Water Act (SDWA). The TCR rule was published in the June 29, 1989, Federal Register. The SDWA requires the EPA review and to revise as needed the National Primary Drinking Water Regulation and those rules that fall under that regulation. As a result of the review, the RTCR was recommended to update and improve the existing TCR. The stated goal of the new rule is to improve public health by reducing the potential for water distribution system contamination by fecal matter, and/or waterborne pathogens, including bacteria, viruses, and parasitic protozoa, according to the EPA's proposed rule that was published in the July 14, 2010, Federal Register issue.

Total coliforms are considered a group of related bacteria found in the environment that generally are considered to be unharmful to human health, according to the July 14 Federal Register publication of the proposed rule. The EPA noted that coliform bacteria are found in mammal feces, but may also be found in aquatic environments, in soil, and on vegetation.

While the agency said that total coliforms are a useful indicator that fecal contaminants may to get into drinking water distribution systems, it considers E. coli a better indicator of actual fecal contamination than fecal coliforms or total coliforms. E. coli is a restricted group of coliform bacteria that nearly always come from human or mammal guts. About 10% of the E. coli strains are considered pathogenic to humans, the EPA said.

The complete article reviewing the EPA proposals and other current content in the October ULTRAPURE WATER journal is available at http://www.ultrapurewater.com. The October issue also features technical articles on semiconductor water treatment, ion exchange, chlorine disinfection, and differences in high-purity water treatment.

Authors Alan Knapp and Gareth Thomas discuss the use of an advanced oxidation treatment process for the removal of inorganic and organic contaminants in semiconductor water. This process is able to reduce total organic carbon (TOC) levels from chloroform, urea, isopropyl alcohol, and other organics down to sub-parts-per-billion levels. Semiconductor manufacturers find such water treatment technologies important as the line widths on microelectronic devices become smaller and the highest purity process waters are needed to protect against device defects. The article by Mr. Knapp and Mr. Gareth explains the advanced oxidation process and its usefulness in maintaining semiconductor water quality during plant operation.

Author Peter Meyers provides a first-person review on the use of packed-bed ion exchange (IX) based on his work in the water business. The article examines pack-bed IX technology and the operation of such equipment installed back in the 1970s. Pack-bed IX systems are designed so that the IX resin essentially fills the entire vessel.

In his review, Mr. Myers examines to operation of a more than 35-year-old packed-bed IX system at a phosphate mine in Bartow, Fla. While much of the equipment is original, the system's piping, and controls have had updates. The article chronicles the operation and maintenance of this IX system, and makes observations about lessons from this and other systems that can be applied to the operation of other packed-bed IX systems.

Lucy Wu and Nik Krpan examine the impact of chlorine on polyamide reverse osmosis membranes. Chlorine is a common disinfectant used in drinking water systems, but residual chlorine must be removed in pharmaceutical plants using reverse osmosis water treatment. Pharmaceutical plants are required to use incoming water that meets EPA drinking water standards. However, such water contains residual chlorine, which must be removed, or it will damage polyamide RO membranes. The article by Ms. Wu and Mr. Krpan investigates the passage of dilute chlorine solutions through polyamide RO membranes and the resulting problems that may be caused.

The October Back to Basics column by Robert Decker reviews types of treated water and differences in the treatment standards and purification processes. Types highlighted by Mr. Decker included bottled drinking water, pharmaceutical water, boiler feedwater, and semiconductor water. For each category, he examines common treatment technologies associated with their production and what quality standards guide endusers when producing each kind of treated high-purity water.

In addition to these technical articles, the October issue also features news briefs and information about the November Ultrapure Water Micro 2010 conference (http://www.talloaks.com/Expo/Phoenix.htm). Ultrapure Water's October on-line issue is available at http://www.ultrapurewater.com. Information on Premier Subscriptions are available at the Ultrapure Water web site, or one may also send an email to: info@ultrapurewater.com, or call 303/973-6700.