The Reclamation of Drinking Water from Sewage

Indirect reuse of wastewaters in drinking water supplies is common practice in industrialized states today. The investigations reported upon have been directed towards improvements upon existing techniques more applicable to the tropical and savanna developing country. High costs and technical difficulties have been encountered in the removal of nitrogen and low level organics. In this study, investigations have been conducted into nitrogen stripping by photosynthetic algal growth, using the nitrogen as a nutrient with subsequent algae harvest from ponds, and low level organics reduction by (a) powdered activated carbon treatment and (b) semi-rapid filtration. Several processes including high rate treatment oxidation ponds, dissolved air flotation, roughing filtration, photosynthetic nitrogen stripping ponds, powdered activated carbon adsorption, dual-media filtration and chlorination were developed and specifically applied to domestic wastewater reclamation for drinking water. These were incorporated into two process streams, one using activated carbon for low level organics removal and the other semi-rapid filtration.