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.

This article examines the application of biological treatment strategies to current problems of the water industry. The studies focused on the production of biologically stable water, increased disinfectant stability, and reduced formation of disinfection by‐products. Results show that biological processes can meet the practical as well as the regulatory requirements of the industry.

Measurements and modeling of the adsorption of natural organic matter (NOM) on oxide surfaces are presented and compared. Agreement is good and supports the view that the adsorption of NOM on oxides depends significantly on complex formation reactions between specific sites on oxide surfaces and functional groups on the NOM. Coagulant requirements can and often are set by the total organic carbon (TOC) concentration in a water source. Frequently there is a stoichiometric relationship between the required coagulant dosage and the TOC of the water to be treated. Other important factors include pH and the concentration of divalent cations. Ozone may benefit or retard coagulation, depending on coagulant type and the water quality characteristic that is dominant in setting the optimum coagulant dose.

A survey of 94 water companies and districts was conducted in early 1988 to determine lead levels at customer taps and to evaluate the factors that influence these levels. The results of the survey indicate that lead‐based solder is the most significant source of lead at the tap. In addition, brass faucets were found to contribute substantially to the lead in the first‐draw samples. Although water quality and site characteristics cannot be used to predict lead levels, certain factors are associated with higher lead concentrations. Other than the presence of corrosion inhibitors, pH was the only water quality factor that appeared to influence lead levels at the tap. Site factors were also important, with plumbing age being the most significant.

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