Co-Treatment of Landfill Leachate and Dairy Wastewater in Anaerobic Membrane Bioreactor: Effect of Landfill Leachate Ultrasound Pretreatment

Landfill leachate is highly concentrated wastewater containing non-biodegradable organic compounds and toxic substances. For this reason, advanced treatment methods are necessary for its treatment. The article discusses the possibility of treating leachate in a hybrid system combining ultrasonic pretreatment and anaerobic co-digestion with dairy wastewater in an anaerobic membrane bioreactor. Two laboratory-scale submerged anaerobic membrane reactors with a capillary module with membranes with a pore size of 0.1 μm and an effective filtration area of 0.35 m2 were used in this study. An ultrasound disintegrator at 22 kHz (amplitude 14 µm) was used for leachate pretreatment. It was found that, as a result of leachate sonification (time > 10 min), the BOD5/COD ratio in the wastewater increased from 0.1 to 0.4, and the content of dissolved organic compounds accounted for more than 40% of the total COD. Preliminary sonication of the leachate resulted in improved co-digestion efficiency in a reactor fed with conditioned leachate. A 92% reduction in organic pollutants was achieved, as well as a biogas production rate of 0.5 L biogas/g COD removed.