An assessment of the feasibility of anaerobic digestion as a treatment method for high strength or toxic organic effluents

The anaerobic digestion process converts organic materials into a methane-rich biogas. The KwaZulu-Natal region has the potential to attract a significant amount of industry. The objective of this research was to assess the feasibility of using anaerobic digestion as a treatment method for high-strength or toxic organic effluents. A strategy was developed to evaluate the degradability and toxicity of effluents and, ultimately, predict the efficiency of treatment in a full-scale digester. This paper details the strategy and investigates the degradation potential of a textile size effluent (COD ca. 140,000 mg/l). The ultimate degradability of the effluent was determined as well as the concentrations and volumes, which could be treated effectively. The inhibitory components of the size effluent were found to be Plystran (10 mg/l) and the biocide (5 mg/l). Anaerobic digestion was found to be feasible, on a laboratory-scale. These results are being applied for scale-up, to full-scale implementation in an existing anaerobic digester.