Direct Filtration of Virginia Surface Waters: Feasibility and Costs

摘要

This research investigated the technical and economic feasibility of the direct filtration technique for treating high-quality Virginia surface waters prior to domestic use. One of the flow schemes that was investigated eliminates the sedimentation basin while employing a full, conventional flocculation period. Another eliminates separate sedimentation and flocculation units altogether. Major variables that were assessed in terms of their effects on direct filtration performances included raw water characteristics such as turbidity, color, total dissolved solids, total hardness, algae count, and total coliform count; filter design variables such as type and size of media (two dual media filters and one trimedia were evaluated); and operating variables such as hydraulic loading rate and nature and dosage of applied coagulant.