Use of a Sonocatalytic Process to Improve the Biodegradability of Landfill Leachate

Landfill leachate is one of the most important sources of toxic organic compounds for ground and surface waters. Advanced oxidation processes can offer an effective and environmentally friendly method for pretreatment of landfill leachates. In this study, an ultrasonic process was used for the pre-treatment of landfill leachate with the objective of improving its overall biodegradability, evaluated in terms of the BOD5/COD ratio, up to a value compatible with biological treatment. Under optimized experimental conditions (pH of 10, power of 110 watts, frequency of 60 kHz, TiO2 concentration of 5 mg/L and exposure time of 120 min), this method showed suitability for partial removal of chemical oxygen demand (COD). The biodegradability was significantly improved (BOD5/COD increased from 0.210 to 0.786) which allowed an almost total removal of COD by a sequential activated sludge process.