Abstract
Anaerobic ponds are particularly effective in treating high-strength wastewater containing biodegradable solids as they achieve
the dual purpose of particulate settlement and organic removal. Performance of an anaerobic pond system for treatment of starch
wastewater containing high organic carbon, biodegradable starch particulate matter and cyanide was assessed under tropical climate
conditions. Approximately 5000 m3/d of wastewater from starch industry was treated in a series of anaerobic ponds with a total area
of 7.39 ha followed by facultative ponds with an area of 29.11 ha. Overall COD and TSS removal of over 90% and CN removal of
51% was observed. Active biomass obtained from the anaerobic ponds sediments and bulk liquid layer exhibited specific methanogenic
activity of 20.7 and 11.3 ml CH4/g VSS d, respectively. The cyanide degradability of sludge at initial cyanide concentration of
10 and 20 mg/l were determined to be 0.43 and 0.84 mg CN/g VSS d, respectively. A separate settling column experiment with
starch wastewater revealed that a settling time of approximately 120 min is sufficient to remove 90–95% of the influent TSS.
2004 Elsevier Ltd. All rights reserved.