IJV absorbance at 254 nm is an excellent surrogate parameter for estimating the raw water concentrations of organic carbon (NPTOC-nonpurgeable total organic carbon) and THM precursors (TTHMFP-total trihalomethane formation potential) in the Grasse River (highly colored water) and the Glenmore Reservoir (protected, upland source). The raw water surrogate equations developed from the Grasse River data were tested successfully on other waters. Direct filtration pilot-plant data demonstrated that IJV can be used to monitor pilot-plant performance for removals of NPTOC and THM precursors. For two plants studied, UV was an excellent predictor of plant performance for removals of NPTOC and THM precursors. Instantaneous TTHMs of the finished waters can be predicted from raw water UV, finished water pH, chlorine consumption, and temperature data. Particular attention should be given to the selection of sampling locations and to the sample-handling conditions.

Research ers con du cted prelim in ary en h an ced coagu lation tests at th e Metropolitan Water District of Sou th ern Californ ia's (MWDSC's) 5.5-m gd dem on stration plan t from Au gu st to October 1992. Californ ia State Project water an d Colorado River water were tested. Th e first goal was to determ in e wh eth er th is m ode of operation is an effective strategy for con trollin g disin fection by-produ cts (DBPs) an d DBP precu rsors at MWDSC facilities. If th is strategy proved to be su ccessfu l, th e secon d objective was to estim ate th e addition al operation al costs of com plyin g with th e proposed Disin fectan ts/ DBP Ru le an d to iden tify th e coagu lation con dition s th at m in im ize th ese costs. Alth ou gh th e resu lts sh ow th at en h an ced coagu lation can m eet th e criteria bein g con sidered for th e ru le, th is process will in crease MWDSC's cost of treatm en t.The 5.5-mgd oxidation demonstration project, where the tests were conducted, is located within MWDSC's 450-mgd Weymouth Filtration Plant complex.

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A pilot‐scale pipe loop test was conducted to evaluate the effects of desalinated seawater on corrosion, lead release, disinfectant decay, and formation of disinfection by‐products in the distribution system. Results indicated that the desalinated blend water did not increase corrosion of unlined cast‐iron pipes, coated cement‐lined pipes, or copper pipes. However, aluminum release from uncoated cement‐lined pipes was increased. The blend water also increased lead release from leaded solder. These results agreed with the predictions from corrosion indexes and earlier bench‐scale testing. Orthophosphate (1 mg/L) added to mitigate lead release was ineffective. Adding phosphate increased bacterial growth in unlined cast‐iron pipes and solder. Although chloramine decay was increased by desalinated water, this effect can be managed by controlling bromide levels and either reboosting or preforming chloramine. Desalinated blend water did not increase biological activity. In addition, the blend water decreased the formation of total trihalomethanes and haloacetic acids as expected but increased nitrosodimethylamine for unknown reasons.