Optimization of anaerobic filter reactor with zeolite immobilization media for dairy sludge waste treatment for biogas production

Sludge from the dairy industry's wastewater treatment contains a high organic content and a strong odor. It is proposed to treat the sludge by an anaerobic digestion process using a continuous anaerobic filter reactor (AFR) equipped with media immobilization support and a combination of ORP and pH sensors. Three immobilized media were put into different AFRs. The process took place in a cylindrical reactor with a column height of 150 cm and diameter of 63 cm with a total volume of 30 L. The total period of the anaerobic digestion process took place 17 days after the batch process. When the experiment was carried out using a flow-rate of 5 L/day, the highest sCOD removal of 90.44 was using bioring media. Meanwhile, using flow-rate of 8L/day the highest sCOD removal up to 88.05 was achieved by using zeolite media. The highest average methane production was obtained 8 mL/day and 24 mL/day of zeolite media by using flow-rate 5 L/day and 8 L/day respectively and reduced HRT up to 90 hours. To ensure the cellular activity on degradation of organic compounds is measured by Oxidation Reduction Potential (ORP) value. In the first stage, the ORP value is -60.23 mV to -472.82 mV for a flow-rate of 5 L/day subsequently the second stage is -471.9 mV to -477.75 mV for a flow-rate of 8 L/day. Anaerobic filter reactors using zeolite media can retain the effect of influent perturbation with a high range of alteration of sCOD and high recovery.