The role of activated sludge solids in a high rate clarification system.

摘要

This research was conducted using jar tests to investigate the impact of adding activated sludge at the headworks of the treatment plant to the ActifloRTM process, a high rate clarification system. Attention was focused on BOD removal performance and the impact on chemical dosages in the ActifloRTM process with the addition of activated sludge. The high rate clarification system simulation was carried out using wastewater samples from the Village Creek wastewater treatment plant in Fort Worth, Texas. A complete study of dosages and impacts of ferric sulfate, polymer, microsand and activated sludge on other aspects of the ActifloRTM process was investigated. Experiments were designed to determine the dosages of activated sludge and other chemicals necessary to achieve an effluent BOD5 level of 30mg/L in the process, which is compared to an effluent BOD5 level of 45 mg/L without adding additional activated sludge. The average total BOD5 was 46.2 mg/L in a baseline chemical condition, where the dosages are ferric sulfate = 105 mg/L, polymer = 1.0 mg/L and microsand = 3.0 g/L. The BOD5 removal was enhanced by adsorption into and bioflocculation onto activated sludge. With a ∼500mg/L dose of activated sludge and 15 minutes mixing time, the effluent BOD removal efficiency was enhanced by approximately 30% using lower chemical dosages in jar tests.