How can wwtp become more sustainable?
There are several ways for WWTPs to become more sustainable, both in the short-term and long-term. In the short-term, WWTPs can be optimised in several ways and slightly redesigned, which can reduce the energy costs. Most of our existing plants were designed and built in the 1960’s and 70’s. We could replace (inefficient) surface aeration with bubble-aeration to save up to 25% of electric energy. Moreover, back then, heat coming from the CHP’s was only used for heating the digesters and the buildings on site. At times, heat was released with coolers into the air. We now regard heat as thermal energy and try to find consumers for it.
Furthermore, resource recovery, such as bioplastics and phosphorous for instance, has huge potential. Making the transfer from chemical to biological P-removal also has a huge impact on the environment, like in our Nereda plants in Epe and Terwolde. As for in the long-term, doing more local wastewater treatment, for instance within one suburb or street, would also make the treatment process more sustainable. This would help reduce the energy use for transport of the wastewater and keep the treated water within areas that are now influenced by draught. In addition, water factories, like the one we are piloting and designing in Wilp, are also what I see as the future of sustainable wastewater treatment. In Wilp, we will be using a new purification concept called “the Waterfactory” to make clean water to prevent drought in the area and raw materials will be extracted from the wastewater.