Biological treatment of a landfill leachate in sequencing batch reactors

A landfill leachate is treated, after mixing with chemical manufacturing wastewaters, by activated carbon adsorption. Biotreatment of the combined wastewater in sequencing batch reactors (SBRs) reduced the carbon requirement by 90%. Excellent treatment efficiency was consistently achieved under a variety of operating conditions: wastewater TOC, feed rate, hydraulic retention time, MLSS, organic loading, temperature, and cycle time. The SBR performance was unaffected when wastewater feeding was suspended during weekends and holidays. Results obtained in 1-L SBRs were reproduced in 12-L and 500-L units. The experimental data served as the basis for design of a full-scale SBR-adsorption system. The integrated wastewater treatment system would produce a better quality effluent at a lower overall cost. Biodegradation rates for some of the more persistent wastewater constituents were enhanced in batch bioreactors which were supplemented with strains of bacteria isolated from the landfill site.