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

Abstract

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.

Elimination of pharmaceutical residues in biologically pre-treated hospital wastewater using advanced UV irradiation technology: A comparative assessment

“…It is worth pointing out that the pilot study could directly feed the LCA with first-hand data. This makes the present work particularly coherent and closes the gap in previous investigations [11,12].…”

The presence of pharmaceuticals in the environment due to human use – present knowledge and future challenges

“…Qiting and Xiheng, 1988;Zwiener and Frimmel, 2004;Ravina et al, 2002;Kiffmeyer, 2003;Ternes et al, 2003;Watkinson et al, 2007;Strä ssle, 2007;Isidori et al, 2007), filtration (Schrö der, 2002;Drewes et al, 2002;Heberer and Feldmann, 2005), application of powdered charcoal (Metzger et al, 2005;Nowotny et al, 2007) and the use of man-made wetlands (Matamoros and Bayona, 2006). Reviews on the advantages and disadvantages of the different technologies are available (Schulte-Oehlmann et al, 2007;Wenzel et al, 2008;Ternes and Joss, 2006). However, all of these technologies have more or less specific shortcomings:…”

“…None of the technologies can remove all of the compounds (Qiting and Xiheng, 1988;Ravina et al, 2002;Schrö der, 2002;Ternes et al, 2003;Wenzel et al, 2008). Will they work for future compounds?…”

“…Additionally, slow sand filtration that is already established in some European STPs may be equally effective. Wenzel et al (2008) investigated the advantages and disadvantages of advanced wastewater treatment of micro-pollutants using environmental life cycle assessment (LCA) and a literature review of advanced treatment performance. The LCA evaluation included sand filtration, ozonation and membrane bioreactors and assessed the effect of extending existing tertiary treatment with these technologies on a variety of micro-pollutants (heavy metals, endocrine disruptors, PAH, phthalates, and detergents).…”

A model of the transient kinetics of laccase-catalyzed oxidation of phenol at micromolar concentrations

“…This may be problematic when the sludges are subsequently applied to land since these contaminants can threaten crop yields, long term soil quality, wildlife and eventually human health [23][24][25]. Research has shown that these compounds can be treated using advanced oxidation processes, but improvements in effluent quality comes at the considerable expense of increased materials and energy consumption [26]. For this reason, alternative processes are sought that can target these compounds for treatment in a more efficient and effective manner.…”