Studies on SAGO wastewater treatment using anaerobic rotating biological contactor

Abstract

 Experimental studies were done in a laboratory scale Anaerobic Rotating Biological Contactor (RBC), for treatment of Synthetic sago wastewater. This paper describes the development and laboratory testing of an Anaerobic RBC process that couples the advantages of the fixed film horizontal flow RBC process with the high strength, starch degradation capabilities of anaerobic systems. The reactor was operated at ambient temperature and was subjected to organic and hydraulic loading rates. The reactor performance with respect to Chemical Oxygen Demand (COD) removal, alkalinity, volatile acids at each stage and biogas production were evaluated.

The Anaerobic RBC reactor liquid volume is 70 litres and total disc surface area is 4.45 m². The reactor was operated with about 100% of the disc area submerged and with a rotational speed held constant at 9 rev/min. The synthetic sago wastewater was started with a COD value of 1087 mg/l at a hydraulic retention time(HRT) of 42 h and it was varied till maximum COD of 9522 mg/l. From the present study, the optimum COD load was found to be 6860 mg/l with a COD removal efficiency of 97.2%.With this optimum COD load, hydraulic loading rate(HLR) study was done at 24 h to 48 h HRT. COD removal efficiencies at hydraulic loading rates were compared with the work of Subrahmanyam & Sastry (1988). From the present study, the proportionality coefficient was found to be 1.18 with process efficiencies at different hydraulic loading rates.