SYNTHETIC WASTE WATER TREATMENT BY CROSS FLOW MEMBRANE BIOREACTOR

Abstract

Use of cross flow membrane bioreactor for the treatment of synthetic wastewater has been investigated in this dissertation. A laboratory scale bioreactor, 20 L volume, was used in this study. It was started up using sludge recycled in activated sludge process. Nine household aquarium type aerators have been used for aeration. The performance of the reactor was evaluated for the MLSS concentration in between 3000-4000 mg/I and the organic loading rate is 0.8-1.5 kg/m3.day. The reactor was run at 12, 10 and 8 hrs HRT until it reached the steady state in each case. The performance of the reactor was studied on the basis of the removal efficiency of the Total COD, Soluble COD, Total Phosphate , Ortho phosphate , TKN , Ammonia and Nitrate at different HRT's using medium strength synthetic wastewater, 400-500mg/L COD with COD:N:P at 100:30:1. The removal efficiency of COD was 89 - 91 %, Soluble COD 88-92%, Phosphate and Ortho phosphate 100%, TKN 82-85 % and Ammonium 85-88% respectively. The maximum efficiency was observed at 12 hr 1-IRT. The Monod kinetics coefficients have also been determined. The following values have been found: 1-lalf velocity, Ks = 271.04 mg/l, maximum specific substrate utilization rate Urn = 0.294 /day, endogeneous decay rate constant, kd = 0.116 /day and observed biomass yield coefficient, Y = 0.233 mg/mg COD. Fouling potential of the filtration module was also investigated. The module was operated for 5 hr daily. Curve between permeate volume and time that there is reduction in the permeate volume from 1000 ml to 930 ml in 12 hrs.