By Michael Rothenborg and Martin Zoffmann
From a necessary evil to a valuable resource.
The status of wastewater has improved tremendously over the past few years. This is mainly because water and wastewater treatment (W&WT) plants have become more efficient and innovative, enhancing their processes and thus maximising output use by recovering energy and nutrients, recuperating organic matter and producing clean, reusable water – sometimes even drinkable – instead of simply regarding it as waste.
“These plants are becoming multifunctional: The original prime function is, of course, to improve public health. The biggest new value is good water resource management and a healthy natural water ecosystem,” says Mark van Loosdrecht, Professor of Environmental Biotechnology and Wastewater Engineering at Delft University of Technology, the Netherlands.
He adds that energy recovery can sometimes also be a good business case – for example, when it reduces the cost of sludge disposal. Moreover, he points out that systems that truly generate income from wastewater treatment have a major advantage because they are used not only in countries with big public sectors but also in countries where private companies handle wastewater treatment.