Wenzel, Henrik6; Larsen, Henrik Fred3; Clauson-Kaas, Jes4; Høibye, Linda4; Jacobsen, Bo Neergaard5
1 Institute of Chemical Engineering, Biotechnology and Environmental Technology, Faculty of Engineering, SDU2 Faculty of Engineering, SDU3 Institut for Produktudvikling4 COWI A/S5 Spildevandscenter Avedøre6 Institute of Chemical Engineering, Biotechnology and Environmental Technology, Faculty of Engineering, SDU
Much research and development effort is directed towards advances in municipal wastewater treatment aiming at reducing the effluent content of micro-pollutants and pathogens. The objective is to further reduce the eco-toxicity, hormone effects and pathogenic effects of the effluent. Such further polishing of the effluent, however, involves an environmental trade-off: the reduction in eco-toxicity, hormone effects, etc. will happen at the expense of increased resource- and energy consumption. Obviously, at some point of further advances, there must be an ‘environmental break-even'. This trade-off was investigated using Life Cycle Assessment (LCA) methodology and based on a literature review of advanced treatment performance. The LCA evaluation comprised sand filtration, ozonation and MBRs and assessed the effect of extending existing tertiary treatment with these technologies on a variety of micro-pollutants being: heavy metals (Cd, Pb, Ni), endocrine disruptors (E2 and EE2), PAH, DEHP, and detergents (LAS & NPE). It was found, in some of the studied scenarios, that more environmental impact may be induced than removed by the advanced treatment. The study showed that for the 3 technologies, sand filtration has the best balance between prevented and induced impacts, and sand filtration proved to have a net environmental benefit under the assumptions used in the study. But the outcome of the study suggests that this is not always the case for ozonation and MBR.
Micropol & Ecohazard 2007: 5th Iwa Specialised Conference on Assessment and Control of Micropollutants/hazardous Substances in Water, 2007, p. 193-200