AWWA WQTC50366

In Pennsylvania, approximately 8 million of the state's 12 million residents receive water from 329 surface water treatment plants. This study evaluated the performance of a subset of these plants and whether they are prepared to meet the turbidity treatment technique requirements of the federal Enhanced Surface Water Treatment Rule. Using 75 filter plants, the authors reviewed key water quality, design and operational variables to determine their influences on filtered water turbidity. Except for plants that did not use a coagulant, served populations less than 3,300 or used streams for a water source, there was no strong statistical correlation between any of the variables and filtered water turbidity. Many plants were able to consistently achieve very low turbidity levels despite limitations such as small system size, plant age or high source water turbidity. The results of this study indicate that intangible variables such as commitment to achieving low turbidity, operator skill level and operator attention appear to be more important than tangible variables such as source water quality, ownership type, plant age, coagulant type, and other operational or design factors. Includes 10 references, tables, figures.