DEVELOPMENT OF A KINETIC MODEL FOR BIOLOGICAL SULPHATE REDUCTION WITH PRIMARY SEWAGE SLUDGE AS SUBSTRATE

The Rhodes BioSURE Process is a low cost active treatment system for acid mine drainage (AMD) waters (Rose et al., 2002). Central to this process is biological sulphate reduction (BSR) using primary sewage sludge (PSS) as the electron donor and organic carbon source, with the concomitant reduction of sulphate to sulphide and production of alkalinity. To optimise the design, operation and control of (and research into) BSR with PSS, a mathematical kinetic model would be an invaluable aid. This study describes the development of such a kinetic model. Sötemann et al. (2005) have proposed a two phase (aqeous / gas) physical, biological and chemical processes kinetic model for the methanogenic anaerobic digestion of sewage sludges (UCTADM1). This model incorporates biological processes for sewage sludge hydrolysis / solubilisation (usually the rate limiting step) and acidification, acetogenesis, and acetotrophic(clastic) and hydrogenotrophic methanogenesis. Additionally, the background weak acid/base chemistry for water, carbonate, acetate, propionate, ammonium and phosphate species have been included, as well as the physical gas exchanges for carbon dioxide an