Effect of anaerobic-O5xic-anoxic (AOA) sequence on the elimination of organic matter, phosphorus and nitrogen in a modified SBR at laboratory scale

Abstract

The effect of AOA (anaerobic, aerobic, anoxic) sequence was studied in the operation of a modified sequential batch reactor, at laboratory scale, under conditions of suspended and attached biological growth SAG-SBR, in order to verify the simultaneous removal of organic matter and nutrients (nitrogen and phosphorus). An acrylic reactor was used with a useful volume of 10,2 liters, that integrated a stirrer, internal recirculation and aeration system, synthetic sewage (SW) was used for simulating a domestic wastewater of medium concentration and the means of contact were spheres and concentric cylinders of polypropylene. During the research, the AOA sequence was used with different cycles and duration times (A = 15.5 h, B = 13 h, C = 11.5 h, D = 9.5 h) applying at the end the sedimentation of mixture liquor. An accurate monitoring of the most important parameters of control process such as dissolved oxygen (DO), pH, temperature and potential oxidation reduction was made and significant results were obtained in the analyzed physicochemical parameters as chemical demand oxygen (CDO), nitrogen and phosphorus, particularly with greater efficiency in lower hydraulic retention time. It is like that removals were achieved in MO the order of 97%, 71% nitrogen and 40% phosphorus. The cycle with the best performing was D, with a total time of 9.5 hours and a removal of 96.6% of MO, 70% N and 51.2% P. © 2017, Universidad de Tarapaca. All rights reserved.