Global expectations for wastewater service infrastructure have evolved over time, and the standard treatment methods used by wastewater treatment plants (WWTPs) are facing issues related to problem shifting due to the current emphasis on sustainability. A transition in WWTPs toward reuse of wastewater-derived resources is recognised as a promising solution for overcoming these obstacles. However, it remains uncertain whether this approach can reduce the environmental footprint of WWTPs. To test this hypothesis, the authors conducted a net environmental benefit calculation for several scenarios for more than 50 individual countries over a 20-year time frame. For developed countries, the resource recovery approach resulted in 154% net increase in the environmental performance of WWTPs compared with the traditional substance elimination approach, whereas this value decreased to 60% for developing countries. Subsequently, a probabilistic analysis was conducted integrating these estimates with national values and determined that, if this transition was attempted for WWTPs in developed countries, it would have a 65% probability of attaining net environmental benefits. However, this estimate decreased greatly to 10% for developing countries, implying a substantial risk of failure. The authors concluded that these results suggest that implementation of this transition for WWTPs should be studied carefully in different temporal and spatial contexts. Developing countries should customise their approach to realising more sustainable WWTPs, rather than attempting to simply replicate the successful models of developed countries. Results derived from the model forecasting highlight the role of bioenergy generation and reduced use of chemicals in improving the sustainability of WWTPs in developing countries.
Authors: Wang X, McCarty PL, Liu J, Ren NQ, Lee DJ, Yu HQ, Qian Y, Qu J. ;Full Source: Proceedings of the National Academy of Sciences, USA. 2015 Feb 3;112(5):1630-5. doi: 10.1073/pnas.1410715112. Epub 2015 Jan 20. ;