Geestmerambacht energy and raw materials plant
HHNK plans to build an energy and raw materials plant at the Geestmerambacht wastewater treatment plant (WWTP). This energy and raw materials plant consists of two components: a central sludge digestion plant with a green gas facility and the construction of one or two wind turbines. The construction of the central sludge digestion plant and the wind turbine(s) are not linked and each follows its own process and schedule. Here, we provide information about the construction of the central sludge digestion plant with a green gas facility.
Latest status of the project
Centralized Sludge Digestion
HHNK has applied for an environmental permit for the construction of the central sludge digestion plant. This application was submitted to the North Sea Canal Area Environmental Agency (ODNZKG), the competent authority responsible for granting this licence.
The ODNZKG has received the application and has requested that we provide additional information. Some of this information depends on the ongoing design process. As soon as this information is available, we will submit it to the ODNZKG, after which the application will be processed further.
Once the ODNZKG has adopted a (draft) decision, that decision is officially published. This publication also includes a link to the related documents on Official Publications.
Emergency Warehouse
In an earlier phase of the project, an “ licence ” was also requested for the relocation of the emergency shelter. Further development of the design has since shown that relocating the emergency shelter is not necessary. The “ licence ” for relocating the emergency shelter has therefore been withdrawn.
Other Permits on the Wastewater Treatment Plant Site
A notice ( licence ) has been published on Overheid.nl (Official Announcements) regarding the permanent maintenance of a warehouse for the storage of equipment on the grounds of the Geestmerambacht wastewater treatment plant. This notice ( licence ) pertains to a warehouse other than the emergency warehouse and is not part of the development of the central sludge digestion plant.
A notice of intent ( licence ) has also been published on Overheid.nl (Official Announcements) regarding the renovation of the effluent pumping station. This pumping station is located on the southwest side of an extension of the wastewater treatment plant site, near the N504. The control building will be slightly expanded to accommodate the modernization of the pumping station’s control systems. The “ licence ” pertains to the control building and is separate from the development of the central sludge digestion plant.
Operating Appropriation
In the summer of 2026, the General Board allocated an implementation budget of €120 million for the construction of the central sludge digestion plant. The budget previously allocated was intended for the project’s preparation and design phases. The implementation budget is intended for the actual construction of the central sludge digestion plant.
What's going to happen?
A central sludge digestion plant with a green gas facility consists of various components. All of these components will be built on the site of the current wastewater treatment plant. Below is a preliminary design of the central sludge digestion plant, which will undergo further technical development in 2026 and 2027.
Where is the project taking place?
The Geestmerambacht wastewater treatment plant is particularly suitable for sludge fermentation. Most of the sewage sludge to be processed comes from this treatment plant. The treatment plant is located in the neighbourhood where the remains of the fermentation plant are further processed into biofuel for the HVC bioenergy plant. The location of the wastewater treatment plant is ideal, close to provincial roads and with little to no expected nuisance to the surrounding area. Part of the site is largely undeveloped and can be made suitable for the construction of the energy and raw materials plant.
When will the project take place and how long will it last?
2026–2027: Develop the preliminary design into a final design and apply for the necessary permits.
Late 2026: Installation of a temporary site office to facilitate the further development of the designs for the various systems.
Early 2028: Construction will begin. You will then see construction activity on the wastewater treatment plant grounds.
No rights can be derived from the schedule. The schedule may be adjusted if work is delayed or takes longer than expected.
Who do we work with?
We are working together with various parties, such as the municipality of Dijk en Waard, the municipality of Schagen, the province of North Holland, and the North Sea Canal Area Environmental Service. At this stage of the project, we would also like to keep local residents and stakeholders in the vicinity of the treatment plant informed of the current situation.
Want to know more?
For more information about this project, please contact Ms. I. Rietveld, environmental manager of the Energy and Raw Materials Plant project, via ourcontact form or via the general telephone number of the water board: 072 - 582 8282.
Background
The water board has fifteen sewage treatment plants. Sewage sludge is released during the treatment of wastewater. All sewage treatment plants together produce approximately 100,000 tons of dewatered sewage sludge annually. A sludge fermentation plant converts biomass (sewage sludge) into biogas. Biogas is converted into green gas and/or electricity. Biogas therefore contributes to sustainable energy generation.
Approximately 55% of the sludge produced is digested in five sludge digestion plants. The remaining 45%, originating from six wastewater treatment plants, is not digested. With the construction of a central sludge digestion plant at the Geestmerambacht wastewater treatment plant, we will be able to digest all of the treatment sludge. As a result, HHNK’s biogas production will increase from 4.3 to 7.7 million m³ per year. By converting the biogas into green gas, HHNK’s green gas production will rise from 1.0 to 3.3 million m³ per year. 3.3 million m³ of green gas corresponds to the annual gas consumption of approximately 2,200 households. In addition, sludge digestion reduces the sludge volume by approximately 30% and theCO₂ footprint by 5,300 metric tonsof CO₂ per year. In 2017 (the start of the Climate and Energy Program), annualCO₂ emissions were 75,000 metric tons. The construction of the central sludge digestion plant will therefore result in a 7% reduction in annualCO₂ emissions. In addition to producing green gas, this facility will recoverCO₂, phosphate, nitrogen, and sulfur from the sludge. Phosphate and nitrogen can be used as fertilizers in agriculture.CO₂ canbe used in greenhouse horticulture or as a refrigerant. As a result, the wastewater treatment plant makes a significant contribution to the circular economy and becomes a true energy and raw materials plant.
Climate neutral by 2035
Generating renewable energy at this site is in line with HHNK’s goal of achieving energy neutrality. The aim is to fully meet its own energy needs and become carbon neutral by 2035.
Background
The water board has fifteen sewage treatment plants. Sewage sludge is released during the treatment of wastewater. All sewage treatment plants together produce approximately 100,000 tons of dewatered sewage sludge annually. A sludge fermentation plant converts biomass (sewage sludge) into biogas. Biogas is converted into green gas and/or electricity. Biogas therefore contributes to sustainable energy generation.
Approximately 55% of sludge production is fermented in five sludge fermentation plants. The remaining 45%, originating from six sewage treatment plants, is not fermented. With the construction of a central sludge fermentation plant at the Geestmerambacht sewage treatment plant, it will be possible to ferment all sewage sludge. This will increase HHNK's biogas production from 4.3 to 7.7 million m³ per year. By converting the biogas into green gas, HHNK's green gas production will increase from 1.0 to 3.3 million m³ per year. 3.3 million m³ of green gas corresponds to the annual gas consumption of approximately 2,200 households. In addition, sludge fermentation reduces the sludge volume by approximately 30% and theCO2 footprint by 5,300 tonsof CO2 per year. In 2017 (start of the Climate and Energy Program), annualCO2 emissions were 75,000 tons. The construction of the central sludge fermentation plant will therefore reduce annualCO2 emissions by 7%. In addition to producing green gas, this plant will recoverCO2, phosphate, nitrogen, and sulfur from the sludge. Phosphate, nitrogen, and sulfur can be used as fertilizers in agriculture. CO2 canbe used in greenhouse horticulture, as a coolant, or in the production of soft drinks. As a result, the treatment plant makes an important contribution to the circular economy and becomes a true energy and raw materials factory.
Climate neutral by 2035
Generating renewable energy at this site is in line with HHNK’s goal of achieving energy neutrality. The aim is to fully meet its own energy needs and become carbon neutral by 2035.