Direct Filtration Using Polyelectrolyte Coagulants

Characteristic of a direct filtration system with dual media filters and catibnic polyelectrolytes as sole coagulants is the formation of a filtration zone that moves down through the bed. The rate of filtration advancement is determined by the pretreatment and filter operating conditions. A rate exists that tends to maximize water production per filter run and avoids turbidity breakthrough before the terminal head loss is reached.