Codigestion of high strength/toxic organic effluents in anaerobic digesters (2006)

The province of KwaZulu-Natal is relatively well endowed with water resources and has thus attracted water intensive industries such as the textile industry. Increasing population and development has increased the pressure on the resource which together with proposed waste discharge charges has lead to increased costs for water supply and wastewater treatment. This has lead to the increasing adoption of various management tools, such as waste minimisation and water conservation.

These methods have proved effective in reducing both the water consumption and the discharge of large volumes of wastewaters. As a consequence, the residues have generally become more concentrated in organic pollutants which are not ideally suited for conventional aerobic treatment systems.

The existence of underutilised anaerobic digesters in the region (Bell, 1997) has suggested the option of anaerobically treating municipal sludge in combination with those high strength industrial effluents which are potentially toxic for the microbial consortia if digested in isolation.

The aims of this project were to:

1. Illustrate that high-strength or toxic organic liquid effluents can be disposed in conventional sewage works at the anaerobic digestion stage.
2. Provide a protocol for the evaluation of liquid effluents for disposal in conventional wastewater treatment digesters.
3. Provide an alternative treatment system for high-strength liquid effluents that are currently being disposed to landfill