Winter Operation of the First United States Flotation Installation - Water Treatment Plants, City of Pittsfield, Massachusetts

摘要

The City of Pittsfield Water Treatment System, Massachusetts, USA, is equipped with six Sandfloat units (2 units at Ashley Plant, and 4 units at Cleveland Plant) each having a capacity of 6.25 MGD. Sandfloat is a compact plant consisting in one unit of flocculation, dissolved air flotation and sand filtration. The performance of Sandfloat Nos. 1 and 2 at Ashley Plant in the period Dec. 4, 1986, to March 20, 1987, is documented in detail. The technical feasibilities of Sandfloat and chemical treatment costs are presented. It is concluded that the mixture of 28% Ashley raw water and 72% Farnham raw water, having moderate alkalinity and low temperature in Winter 1987, can be treated satisfactorily by Sandfloat (Type 49; Diameter 49 ft; Depth 6 ft) at 5.5-5.8 MGD per unit using the chemical combination of sodium aluminate, polymer 1849A and alum. If 100% Farnham raw water with extremely low alkalinity and low pH is to be treated, Ultrion 8157, sodium aluminate and polymer 1849A will be the best chemical combination for proper clarification.