A contribution submitted to the JOURNAL by James M. Symons (Active Member,

Bench‐ and pilot‐scale investigations revealed the influence of precursor compound concentration, pH, type of disinfectant, and temperature on trihalomethane formation. Implications of the research for altering treatment procedures to reduce trihalomethane production are discussed.

The purpose of the Community Water Supply Survey (CWSS) was to determine if the American consumer's drinking water met the Drinking Water Standards presented by the United States Public Health Service (USPHS). To obtain nationwide coverage, the Bureau of Water Hygiene initiated the CWSS in February of 1969 in nine areas across the country. The field work for the CWSS was conducted by the Bureau of Water Hygiene, in cooperation with the state and local health departments of the water utilities. The survey scope, methods and results are presented here.

This article discusses the effectiveness of water treatment processes in coping with relatively small concentrations of pesticides in raw water. Duplicate pilot water treatment plants at the Taft Center were used to evaluate the effectiveness of conventional and auxiliary treatment processes. The methods and procedures used included: the chromatographic method; solubility and incidental loss; coagulation and filtration; chlorine; potassium permanganate; ozone; powdered activated carbon; and, granular activated carbon.

This article discusses treatment modifications including high‐rate filtration with coarse, lightweight media on top of sand; control of floc strength and its passage with polyelectrolytes in the filter influent; the use of filters for flocculation of low alum doses as well as for removal of turbidity; and, the use of granular activated carbon in filter beds. The effect of these innovations was studied in pilot plants of various sizes to determine the passage of coliform bacteria, powdered activated carbon, virus, and gross turbidity through the filters.