Abstract |
The efficacy of combining biological nitrification with each of two modes of chemical clarification is evaluated for production of a water suitable for specific industrial reuse applications. A 7200 gpd pilot plant was constructed, operated and analyzed. In the conventional clarification system, low doses of lime or alum were effective in removing greater than 95% of the BOD, turbidity, and suspended solids from the nitrified secondary effluent. Efficient phosphorus removals necessitated higher lime and alum additions of 300 mg/liter, and 100-150 mg/liter, respectively. At the higher line doses, a two-fold reduction in bacterial organisms was achieved. Specific heavy metals were removed through both alum and lime additions. With either coagulant chemical, practical rapid sand filter runs of 16 hours were possible. Similar removal results were obtained with alum in a high-rate clarification flow system with direct duel-media filtration of alum flocculated wastewater. Filter runs of 5-6 hours could be realized. (Modified author abstract) |