SITE INFORMATION AND CORRESPONDENCE_CASE 2

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CENTRAL VALLEY WATER BOA' RESPONSE (SWRCB/OCC File A-1846). -9- PETITIONS FOR REVIEW OF WASTE DISCHARGE REQUIREMENTS ORDER NO. R5-2007-0036 (NPDES NO. CA0079154) AND TIME SCHEDULE ORDER NO. R5-2007-0037 CITY OF TRACY, WASTEWATER TREATMENT PLANT and CEQA is not required prior to implementation of those objectives in the Permit. (City of Burbank, supra; Wat. Code § 13389.) The Discharger admits that the Office of Administrative Law approved the prospective incorporation by reference. The State Water Board and EPA have also approved the prospective incorporation by reference. (Order WQO 2002-0015 [City of Vacaville].) At any rate, the nitrate and nitrite MCLs were not prospectively adopted, since the Department of Health Services (now the Department of Public Health) adopted them before the Central Valley Water Board adopted the 1994 version of the Basin Plan (9 December 1994). (Attachment 2, which includes a copy of Table 3-5 from the Los Angeles Regional Water Quality Control Board's Basin Plan shows that the current MCLs for nitrate as NO3, nitrate + nitrite (as nitrogen), and nitrite (as nitrogen) have been in effect since at least 8 September 1994.) These objectives have not changed since the Central Valley Water Board's approval of the chemical constituents objective. Untreated domestic wastewater contains ammonia. The Tracy Permit requires the removal of ammonia (i.e., nitrification), which is the process of converting ammonia to nitrite and nitrate. Inadequate or incomplete denitrification (i.e. process of removing nitrite and nitrate) may result in the discharge of nitrate and/or nitrite exceeding the MCLs. Nitrate causes adverse health effects in humans by interfering with the transport of oxygen in the bloodstream, particularly with fetuses and newborn children, a condition known as methemoglobe nem ia, or blue-baby syndrome. In extreme cases the condition can retard physical and mental development, and cause death.5 CONTENTION F: Improper effluent limits for aluminum, which were based on USEPA's recommended National Ambient Water Quality Criteria (NAWQC) for protection of freshwater aquatic life. Specifically, the effluent limits are more stringent than required under federal law, because the average monthly and maximum daily effluent limits are less than the criteria. Furthermore, based on the local conditions, the chronic criterion is not applicable and should not have been used for establishing water quality-based effluent limitations. Appropriate Use of USEPA NAWQC Chronic Criterion. The Central Valley Water Board agrees with the Discharger on this issue. USEPA developed recommended NAWQC for protection of freshwater aquatic life for aluminum. The recommended four-day average (chronic) and one-hour average (acute) criteria are 87 pg/L and 750 Ng/L, respectively. However, information contained in the footnotes to the NAWQC indicate that the development of the chronic criterion was based on specific receiving water conditions where there is low pH (below 6.5) and low hardness levels (below 50 mg/L as CaCO3). The minimum observed hardness in Old River in the vicinity of the discharge was 109 mg/L as CaCO3. The pH in the receiving water is consistently greater than 6.5 (typically greater than or equal to 7). Because the hardness and pH values in Old River are higher (which 5 These impacts are well known. For example, see OEHHA, Public Health Goals for Nitrate and Nitrite in Drinking Water (available at http://oehha.ca.gov/water/phg/pdf/nit2_c.pdf).