Home > Clean Your Water Tanks, Potable Water Tank Cleaning, Potable water tank inspection > The EPA is considering New Rules for tank Inspection & Cleaning

The EPA is considering New Rules for tank Inspection & Cleaning

On July 14th 2010 the The U.S. Environmental Protection Agency  Posted this notice under / Proposed Rules

2. Storage Tank Inspection and Cleaning

EPA requests comment on the value and cost of  periodic storage tank inspection and cleaning . There are instances of storage tanks being the source of waterborne disease outbreaks at PWSs. In December 1993, aSalmonella typhimurium outbreak in Gideon, Missouri resulted in over 600 people affected by diarrhea, 31 cases of laboratory-confirmed salmonellosis and seven deaths of nursing home residents who had exhibited diarrheal illness (four deaths were confirmed by culture). The larger of the two storage tanks had a breach in the roof hatch that allowed pigeon droppings to be carried into the tank and likely accumulated in the several inches of sediment. This contaminated sediment, more than likely, was pulled into the distribution system by a flushing program that  drained the tank (Clark et al. 1996). Salmonella typhimuriumwas isolated from the sediment of one of the towers, and tap water tested positive for fecal coliforms (CDC 1996). In March 2008, Alamosa, Colorado (with a population of about 9,000 people) experienced a waterborne disease outbreak associated withSalmonella. The report released by the Colorado Department of Public Health and Environment (Falco and Williams 2009) indicated that the outbreak resulted in 442 reported cases of illnesses, 122 of which were laboratory confirmed, and one fatality. The State epidemiologist estimated that a total of 1,300 people may have been ill. Two storage tanks in Alamosa had several inches of sediment and breaches; one tank had breaches large enough for birds and animals to enter. Some of the key factors that contributed to these two outbreaks include significant levels of sediment (several inches to feet) and the presence of breaches of the integrity of the storage tank. Sediment accumulation occurs within storage facilities due to quiescent conditions which promote particle setting. Over time sediment continues to accumulate in a tank, even if the finished water is consistently treated tobelow 0.1 nephelometric turbidity unit(NTU). For surface water systems, it isnot uncommon to have 1⁄4 to 1⁄2 inch or more of sediment accumulate after two to three years (Kirmeyer et al. 1999).

While there are no turbidity regulations for ground water systems (except for ground water under the direct influence of surface water (GWUDI)), the levels of turbidity can be significant in the water pumped from an aquifer. Sand particles, if allowed to accumulate, provide pore spaces that house diverse populations ofbiota (which may include pathogenic microorganisms) (Kirmeyer et al. 1999; van der Kooij 2003). Periodic high flows in the storage tank may scour, stir up, and suspend the sediment (along with entrapped bacteria and pathogens) and carry it into the distribution system, with greater accumulation of sediment being a more significant concern. Other water quality problems associated with sediment accumulation include increased disinfectant demand and disinfection byproduct formation. The storage tank’s vulnerability to contamination increases when breaches of the storage tank allow insects, animals, and birds and their associated diseases to enter. Contamination from bird and other animal excrement can potentially transmit disease-causing organisms to the finished water.  Waterfowl, for example, are known carriers of many different waterborne pathogens including Vibrio cholerae(Ogg et al. 1989). Based on the potential public health implications associated with poorly maintained storage tanks (e.g., as indicated by significant sediment accumulation and breaches), EPA is interested in receiving comments and supporting information regarding the state and condition of tanks that have been cleaned and inspected, costs of storage tank inspection and cleaning, and how public health can be better protected. EPA requests information on whether there are States that recommend or require periodic inspection and cleaning of storage tanks. If so, what are the requirements, the frequency of inspection and cleaning, and how successful are they? Are inspections and cleaning done by individual PWSs or by contractors?

DATES: Comments must be received onor before September 13, 2010.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA–HQ–OW–2008–0878, by one of the following methods:

• Federal eRulemaking Portal: http://www.regulations.govFollow the on-line instructions for submitting comments.

• Mail:

Water Docket, Environmental Protection Agency, Mailcode: 4101T, 1200 Pennsylvania Ave., NW., Washington, DC 20460, Attention

Docket ID No. EPA–HQ–OW–2008–0878. In addition, please mail a copy of your comments on the information collection provisions to the Office of Information and Regulatory Affairs, Office of Management and Budget (OMB), Attn: Desk Officer for EPA, 725 17th St., NW., Washington, DC 20503.

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