Waterschap Zuiderzeeland has recently expanded its sludge digestion line. In addition, the conventional fermentation technology is supplemented with an Ephyra installation, resulting in a higher fermentation yield. From now on, not only their own sludge, but also the sludge from the Lelystad WWTP will be processed into biogas. This biogas is burned in a high-efficiency combined heat and power unit (CHP) that generates energy for own use. Biogas Holland was contracted by  Aan de Stegge to realize various installations for this expansion at AWZI Tollebeek. 

Innovative adjustments

The biogas that is created in the digestion by the degradation of sludge is stored in a gas holder and is converted into electricity and heat for own use via a combined heat and power unit (CHP). Two new circulation flows are connected to the existing heat distributor. Adjustments have also been made to the central heating system. The heat produced is mainly used for heating the sludge. A new CHP unit has been installed in order to be able to use the extra biogas produced in all situations. Biogas Holland has also delivered and installed a new gas flare installation. This means that if there is too much biogas supply, part of the biogas will be flared. In the future, the flaring installation will only be used in emergency situations and during maintenance work on the CHP. By making better use of the biogas, it is expected that co-firing on natural gas will barely or no longer be necessary.

Biogas Holland has carried out all documents, drawings, technical specifications, FAT and SAT tests. We also inerted and commissioned the biogas installation.

Climate and energy targets

Waterschap Zuiderzeeland has climate and energy objectives. For example, the water board wants to be 35 to 45% self-sufficient by 2030. With the application of the Ephyra technology, Zuiderzeeland can purify wastewater even more sustainably so that the WKK produces more energy in the form of electricity and heat. Naturally, the CHP installation complies with the current emission requirements.

At the AWZI Tollebeek, the wastewater from the Noordoostpolder is processed, plus the sludge from the AWZI in Lelystad. This renovation contributes to the climate and energy objectives of Waterschap Zuiderzeeland.