Use of Field Crop Residues for Sand Filter Modification of Small Community Wastewater Stabilization Ponds to Meet Secondary Treatment Requirements and Recovery of Plant Nutrient Resources

摘要

Comparisons were made of laboratory scale intermittent sand filters for upgrading wastewater lagoon effluent. Three filters were used. Two were modified with a 45.7 cm (18 in) cover of corn stalks or sunflower stalks. The hydraulic loading rate 4700 cu m. ha/d (0.5 mgad) applied in two equal doses daily. The effective sand size was 0.18 mm. The lagoon effluent characteristics during the study period averaged 102 mg/l Suspended Solids, 42 mg/l BOD5, 169 mg/l COD, 11.4 mg/l TKN, and 2.7 mg/l total P. The filters were operated 57 days before the corn stalk covered filter clogged. All filter effluents averaged less than 30 mg/l BOD5 (13.5 - 18 mg/l). Only the corn stalk covered filter averaged less than 30 mg/l Suspended Solids (23 mg/l).