Abstract
Solid-liquid separation of swine wastewater was conducted using bentonite as coagulant. During the separation experiment, coagulation efficiency was also investigated. To determine optimal bentonite dose, 0.1, 0.2, 0.4, 0.8, and 1.6% (w/v basis) of bentonite was dosed. Suspended solid removal efficiency was 87-98% at whole bentonite dosage. But sediment volume was increased, and settling velocity was decreased at excessive bentonite dosage. Therefore optimal bentonite dosage was evaluated around 0.2-0.4%. In the test to determine optimal pH, coagulation using bentonite was performed at pH 3, 4, 5, 6, and 7. At lower pH suspended solid removal efficiency was increased. However, sediment volume was also increased and phosphorus release was observed. Thereby optimal pH for bentonite coagulation might be appeared in the range of 6-7.