Questioning the excessive use of advanced treatment to remove organic micropollutants from wastewater

Pollution from endocrine disrupting compounds and related micropollutants is widely regarded as a major environmental issue on both a regional and a global scale, largely due to concerns over risks to human and ecological health. Between 2005 and 2010, the United Kingdom is conducting a demonstration program, costing 40 million ($80 million at the time of writing), to evaluate technologies to remove these compounds from wastewater. However, while such advanced treatment techniques will undoubtedly reduce the discharges of micropollutants, they will also inevitably result in large financial costs, as well as environmentally undesirable increases in energy consumption and CO2 emissions. Here we calculate the price of treating urban sewage with two of the major options specifically proposed in the U.K. demonstration program: (i) granular activated carbon and ozone and (ii) membrane filtration and reverse osmosis. Economic analysis indicates that treating wastewater with these advanced technologies may be economically and environmentally undesirable due to the increased energy consumption and associated economic costs and CO2 emissions. Since the costs of advanced treatment of sewage would most likely have to be passed on to customers (both domestic and industrial), we propose that national demonstration programs should not only compare and contrast the most advanced treatment methods but also consider alternative techniques, such as increased sludge ages and hydraulic retention times in conjunction with nutrient removal stages and the varying redox conditions associated with them, which potentially may be almost as effective but with much lower environmental and financial costs.