During spring 2015 Waterboard Scheldestromen launced the tender for the design- and construct of the energy factory for WWTP Walcheren, the Netherlands. The tender concerned the conversion of the WWTP into an energy self-sufficient plant by the end of 2017. Furthermore also general upgrading, modernisation and maintenance works were included in this tender. In July 2016 two of the three lots were awarded to ELIQUO and the design phase started immediately after contract signing. Since February 2017, ELIQUO physically mobilized for construction at WWTP Walcheren and realization of the work has started.

In order to reach the energy self-sufficient performance of the WWTP, ELIQUO will substantially modify the existing sludge processing line as well as the biogas line. Sludge from WWTP Walcheren is digested along with the sludge from nearby located WWTP’s in order to reach the set goals for energy autonomous performance. The works also include the realization of a reactor for controlled struvite precipitation, subsequently the sludge, including the formed struvite crystals, will be dewatered and deposited to a centralised sludge incineration facility. By using the concept of controlled struvite precipitation, dewatering performance will improve (volume reduction). This will lead to operational cost savings for disposal, but also reduce the costs for use of chemical (use of PE).

For this project ELIQUO is cooperating with her sister company PAQUES, both part of the SKion water portfolio. In 2014 SKion took over the shares of ELIQUO Water & Energy BV. Through this cooperation, ELIQUO is providing the ANAMMOX® technology for the removal of nitrogen. ANAMMOX® is developed and patented by PAQUES. Supported by many full-scale operational experiences, this technology can be qualified as “proven and robust”. For the Walcheren project ANAMMOX® will provide nitrogen removal by simultaneous nitrification and de-ammonification resulting in a substantial reduction of oxygen and energy consumption in the water section of the WWTP.

ELIQUO also construct a modern biogas treatment facility in which biological desulfurization with downstream active carbon filtration is applied. This setup will ensure that produced gas will be treated from sulphur (H2S), and siloxanes adequately in order to minimise wear and tear in the new gas engines At Walcheren two modern combined heat and power (CHP) systems of 330 kWe will convert all produced biogas efficiently into electricity as well all necessary heat for the sludge digestion process.

Furthermore ELIQUO will replace several existing installations as well the improvement of gas safety up to the latest national standards.

The project is expected to be finished in 2018.