Flocculants for wastewater life cycle optimisation

The use of flocculants and coagulants in the treatment of municipal waste water was examined using Life Cycle Assessment and Environmental Life Cycle Costing as tools. For a typical wastewater treatment plant with 10-50,000 person-equivalents of capacity, the main environmental impacts and costs are both linked to the transport of the dewatered sludge from the plant as well as its incineration, in examples where thermal drying to pellets is relevant. In comparing flocculants, the resource depletion potential and eutrophication potential are the environmental impact most sensitive, both influenced by the overall sludge dryness.