CONSIDERATIONS INVOLVED IN THE REACTIVATION OF AN EXISTING WATER SUPPLY.

Construction of the Sudbury Reservoir was started around 1890 by the City of Boston and was completed in 1898. However, from the beginning, water from the Sudbury supply was always noted for its relatively poor quality in regard to aesthetic parameters such as color, taste and odour. It was after the drought of the 1960s that reactivation of the Sudbury River supply, by treating the water, was proposed. This paper describes the technical considerations which were evaluated to identify an economical and effective method of treating the Sudbury supply. The results of extensive pilot plant testing of the hydraulic pulsed upflow clarification-filtration and ozonation-filtration systems indicated that both will produce filtered water that satisfies State requirements. However, the hydraulic pulsed upflow clarification-filtration system produced water of an acceptable quality at a filtration rate twice that of the ozonation-filtration system. In general, the hydraulic pulsed upflow clarification-filtration system was affected less by changes in color, turbidity, and algae than the ozonation-filtration system. Estimates of construction and operating costs between the two systems are also discussed.