Complete Treatment of Compost Leachate Using Integrated Biological and Membrane Filtration Processes

A lab-scale SBR equipped with a flat sheet membrane in submerged configuration that is named MSBR was used for treatment of composting leachate. It was fed by biologically treated leachate with overall 70-1360 mg/L Chemical Oxygen Demand (COD). The values of pH, Electrical Conductivity (EC), and Dissolved Oxygen (DO) were monitored routinely. However, analysis of total COD, Soluble COD (SCOD), Biological Oxygen Demand (BOD5), Total Suspended Solids (TSS) and Volatile Suspended Solids (VSS) were done in feed and filtrate, whenever the system reached steady state twice a week for about 6 months. In all loading rate, BOD5 concentration was less than standard limit. The removal efficiency of total COD increased in bioreactor with time in all experiments was up to 80%. Influent SCOD varied spectacularly (50-1050 mg/L) due to the leachate collection during different seasons but in the effluent it remained relatively stable. About 60% of the feed SCOD was non biodegradable type that was separated by the membrane. Up to 99 % further solids was removed with micro pore membrane which might be mainly included in colloidal solids. The value of EC for the leachate sample was 0.86-4 mS/cm in 22 °C which decreased by membrane significantly. It was concluded that, MSBR as a versatile technology with high throughput could treat composting leachate below the standard limit if used after proper processes.