Weighing environmental advantages and disadvantages of advanced wastewater treatment of micro-pollutants using environmental life cycle assessment

• Published in: Water science and technology 2008, Vol.57 (1), p.27-32
• Main Authors: Wenzel, H, Larsen, H F, Clauson-Kaas, J, Høibye, L, Jacobsen, B N
• Format: Article
• Language: English
• Subjects: Advanced wastewater treatment; Bioreactors; Conservation of Natural Resources; Decision Making; Detergents; Ecosystem; Effluents; Endocrine disruptors; Energy consumption; Environmental impact; Environmental Impact Assessment; Filtration; Heavy metals; Lead; Life cycle analysis; Life cycle assessment; Life cycle engineering; Linear alkyl sulfonates; Literature reviews; Metals, Heavy - analysis; Micropollutants; Municipal wastewater; Nickel; Ozonation; Pollutants; R&D; Research & development; Risk Assessment; Sand; Toxicity; Tradeoffs; Waste Disposal, Fluid - methods; Wastewater treatment; Water Microbiology; Water Pollutants, Chemical - analysis; Water Purification - methods; Water treatment plants
• ISSN: 0273-1223; 1996-9732
• DOI: 10.2166/wst.2008.819

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.