Anaerobic co-digestion of potato processing wastewater with pig slurry and abattoir wastewater

BACKGROUND: Small-scale experimental investigations were carried out on the anaerobic digestion of potato processing wastewater and its co-digestion with pig slurry and/or abattoir wastewater. A simple and rapid procedure was used to determine the suitability of these wastes for digestion. RESULTS: During the initial 5-day acclimation phase, the seed (digested brewery waste) was replaced by the test waste before allowing the tests to incubate without further addition, where methanogenesis was measured. Although potato processing wastewater has low pH, with high fat content treatment via anaerobic digestion was still feasible in spite of low methane production. Co-digestion with pig slurry and abattoir wastewater was therefore investigated to enhance the process. Pig slurry improved the process, which, when co-digested with potato processing wastewater in equal ratio achieved 72% volatile solids removal, 35 mL average daily biogas production and 32% maximum methane content in 22 days (following the acclimation period). Co-digestion with abattoir wastewater did not improve the digestion process due to poor buffering and low pH value. CONCLUSION: Anaerobic co-digestion may be a feasible treatment option for industrial bio-wastes and livestock wastes produced in Cyprus and indeed in similar other countries of comparable market size and activities. (C) 2008 Society of Chemical Industry