The Role of Activated Sludge Solids in an Actiflo® System

Chen-An Lien, Andrew P. Kruzic
2006 Proceedings of the Water Environment Federation  
This research was conducted using jar tests to investigate the impact of adding activated sludge solids to the Actiflo ® process, a high-rate clarification (HRC) system, to increase BOD removal in HRC systems treating raw wastewater during periods of high wet-weather flows (WWF). A study of dosages and impacts of ferric sulfate, polymer, microsand and activated sludge on performance of the Actiflo ® process was investigated. Experiments were designed to determine the dosages of activated sludge
more » ... of activated sludge and other chemicals necessary to achieve an effluent BOD 5 level of 30mg/L in this physical-chemical process with an influent BOD 5 concentration of 100 mg/L. With a 490 mg/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. approximately 15 minutes of contact time in the pipe from the headworks to the Actiflo ® process (see Figures 2 and 3) . The Actiflo ® system at the Village Creek WWTP was designed to meet a National Pollutant Discharge Elimination System (NPDES) permit that requires that the effluent BOD 5 from the HRC be less than 45 mg/L at all times. (Sawey et al., 1999) A specific goal of this study was to determine whether activated sludge addition could lower the total effluent BOD 5 and produce an effluent that meets a specific effluent BOD 5 goal (25~35 mg/L BOD 5 ) with a high degree of confidence for influent BOD 5 values as high as 100 mg/L. Fig. 1 Parallel Treatment Train with Conventional Treatment and the Actiflo ® Process (Sawey et al., 1999) 6749 WEFTEC®.06 Polymer: 1.0 mg/L Ferric Sulfate: 105 mg/L Microsand:3 mg/L Non-sludge addition (Baseline Condition) Polymer: 0.5~1.0 mg/L Ferric Sulfate: 52.5~105 mg/L Microsand:3 mg/L Sludge addition 0.0 5.0 10.0 % 7.5 6755 WEFTEC®.06
doi:10.2175/193864706783761626 fatcat:ifqqbcgrkbhmnax3wm6uvfyckq