Surface Water Treatment Rules

POTABLE WATER CHLORINATION 2,1, Surface Water Treatment Rules 

On June 29, 1989, the Surface Water Treatment Rules (SWTR) and the Coliform Rule were promulgated. According to the SWTR, all public water systems using surface water or groundwater under direct influence of surface water, must disinfect and may be required to filter if certain source water quality requirements and site-specific conditions are not met. The Maximum Contaminant Level Goals (MCLGs) established in the rule are  

No MCLGs were set for turbidity and heterotrophic plate count (HPC). Treatment requirements also were established in lieu of MCLs for Giardia, viruses, HPC, Legionella, and turbidity. Treatment must reliably achieve at least 99.9% removal/inactivation of Giardia lamblia cysts and 99.99% removal/inactivation of viruses (1,4,5). 

The Coliform Rule requires all public water systems to meet the coliform MCL and monitor total coliform with frequencies depending on population served, and requires small systems to conduct a sanitary survey. To comply with the coliform MCL, no more than 50% of all total coliform samples per month can be total coliform-positive. 

The chlorination process applied to the water treatment system before the filtration process is prechlorination, predisinfection, or primary disinfection. When chlorination is applied to water treatment after filtration, it is termed postchlorination, postdisinfection, or secondary disinfection. The disinfectants used in primary disinfection and secondary disinfection are termed primary disinfectant and secondary disinfectant, respectively. 

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EPA s surface water treatment rules require systems using surface water or ground water under the direct influence of surface water to (1) disinfect their water, and (2) filter their water or meet criteria for avoiding filtration so that the following contaminants are controlled at the following levels ... 

Enhanced Surface Water Treatment Rule (ESWTR), 17 804... 

Beginning in about 1990, the first microfiltration/ultrafiltration plants were installed to treat municipal surface water supplies [14,15], The driver was implementation of an EPA surface water treatment rule requiring all utilities in the United... 

Letterman, R. D. (1991). Filtration Strategies to Meet the Surface Water Treatment Rule. Am. Water Works Assoc., Denver. 

Diatomaceous earth filter plants have been chosen for projects with limited initial capital, and for emergency or standby capacity to service large seasonal increases in demand. Because these systems are most suitable for applications where influent is low in turbidity and bacterial counts, water supplies presently receiving just chlorination may consider using diatomaceous earth to meet the filtration requirements of the Surface Water Treatment Rules (SWTR) (2). 

In the US EPA publication Small System Compliance Technology List for the Surface Water Treatment Rule (SWTR) and Total Coliform Rule (ICR) (September 1998), DE is a specifically approved filtration technology for compliance with the SWIR. In its comments the US EPA notes that DE is very effective for the removal of Giardia and Cryptosporidium" (23). 

US EPA, Small System Compliance Technology List for the Surface Water Treatment Rule and Total Coliform Rule, US Environmental Protection Agency, Washington, DC, 1998. 

In general, disinfectant dosages will be lessened by placing the point of application towards the end of the water treatment process because of the lower levels of contaminants that would interfere with efficient disinfection. However, water plants with short detention times in clear wells and with nearby first customers may be required to move their point of disinfection upstream to attain the appropriate CT value under the Surface Water Treatment Rule. 

Other primary disinfection technologies—chlorine, chlorine dioxide, ozone, UV radiation, and organic disinfectants—are discussed elsewhere (1-3,17-27) in detail. Because most of the utilities that are affected by the Surface Water Treatment Rules and the Ground-Water Disinfection Treatment Rules serve less than 10,000 persons, this chapter wiU emphasize the applications of chlorination and chloramination processes to both small and large utilities. Table 1 indicates that both chlorination and chloramination are comparatively simpler than ozonation UV processes. 

Vickers J.C., Johnson P.E., WHinghan G.A. (1993), Meeting the surface water treatment rule using... 

Implementation of the 1986 Amendments to SDWA led to the development of a number of important rules, including the Total Coliform Rule, the Surface Water Treatment Rule, the Lead and Copper Rule, and regulations for a large number of chemicals of public health concern. All public water systems using surface water sources were required to disinfect and provide specific levels of treatment for microbial pathogens most systems were required to filter their water. In addition, the best available technology was specified for the treatment of contaminants for which an MCL was established. 

Collect informadon on the Surface Water Treatment Rule (SWTR) standards set by the EPA. Write a brief memo to your instructor eaqplaining your findings. Obtain the EPA s consumer fact sheets (they are now available on the Web) on antimony, barium, beryllium, cadmium, tyanide, and mercury. After readily the fiict sheets, pt >are a brief report explaining what they are, how they are used, and what health effects are associated with them. 

The USEPA has 2 years to list such technologies for current regulations, and 1 year to list such technologies for the surface water treatment rule. 

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