The Co-Treatment of Municipal and Industrial Wastes

Regulatory pressures are forcing major changes on the waste disposal industry. The proposed EU Directive on Landfilling of Waste, if implemented in its current form, will ban the co-disposal of industrial and municipal wastes in landfill. These developments indicate a likelihood that co-disposal will no longer be available as a disposal option for industrial wastes in the long term.Above-ground co-treatment of industrial wastes with sewage sludge and/or municipal solid waste prior to landfill is an approach to enhancing the efficiency of waste disposal to landfill and reducing reliance on incineration. It also provides an alternative to disposal to land where the wastes are considered too toxic. Degrading municipal waste and sewage sludge have been shown to promote the degradation of many toxic organic compounds and fix other organic and inorganic substances, for example as sulphides or into humic matter. These processes are used to justify the practice of co-disposal to landfill. Unfortunately, these processes are not optimised and cannot be controlled in landfill and hence co-disposal has come to be viewed unfavourably in many countries. Optimisation of these processes in an above-ground treatment system would have many advantages, including:1Stabilisation of environmentally damaging substances,2Reduction of waste volumes prior to landfill,3Generation of recoverable biogas ,4Detoxification of hazardous substances in a low temperature biological process, without the input of additional fossil fuel or the likelihood of generating dioxins and furans,5Generation of a benign stabilised residue,6Biological sanitisation of the treated waste stream,7.Disposal of a waste with a reduced capacity to generate landfill gas and possibly improved geotechnical performance.