Anaerobic-aerobic biological treatment of a mixture of cheese whey and dairy manure

Abstract

The integrated anaerobic-aerobic biological treatment system consisted of an anaerobic rotating biological reactor and an aerobic sequencing batch reactor. Three sequencing batch reactors were used in the aerobic process. A mixture of cheese whey and dairy manure was successfully digested in an anaerobic rotating biological contactor which served as a first step in the waste treatment process. The methane production rate, which is dependent on the organic loading rate, ranged between 1·43 and 3·74 litres methane per litre reactor per day. As the organic loading rate increased, total methane production also increased. In the anaerobic digestion step, over 46% of chemical oxygen demand was removed. The potential pollutants were further destroyed by the aerobic treatment. More than 93% of the remaining chemical oxygen demand was removed in the sequencing batch reactors operated at 22°C. The treatment efficiency was lower for the aerobic reactor operated at a lower temperature (10°C). The results indicated that an integrated anaerobic-aerobic treatment of a mixture of dairy manure and cheese whey could produce a substantial amount of methane and reduce the pollution potential.