In the Netherlands, Bright Biomethane has announced that it has been selected to supply a biogas upgrading system with membrane separation technology to the country's largest wastewater treatment plant (WWTP), Delfland Water Authority's Harnaschpolder WWTP. Construction is already underway with the first renewable natural gas (RNG) expected to be supplied to the gas grid already next month, in August 2019.
The Delfland Water Authority is one of the 21 water authorities in the Netherlands and wants to create a working environment that is as sustainable and circular as possible. Delfland has the ambition to be energy neutral by 2025. In addition, the water board also wants to supply green energy to third parties.
The production of renewable natural gas (RNG) is thus another important step in this energy transition. Bright Biomethane already realized an RNG installation for Delfland, at the De Groote Lucht WWTP in Vlaardingen. Operational management and maintenance of the Harnaschpolder wastewater treatment plant (WWTP) in Den Hoorn is carried out by Delfluent Services B.V. on behalf of Delfland Water Authority.
Sludge digestion
At this WWTP, approximately 6.5 million Nm3 of biogas per anum is produced from sludge digestion. The biogas produced consists of around 60 percent methane (CH4) and is not immediately suitable for gas grid injection. Bright Biomethane’s biogas upgrading system will ensure that the biogas is upgraded to renewable natural gas (RNG), also known as biomethane, consisting of 89 percent methane.
Around 4.5 million Nm3 of renewable low-calorific gas (L-gas) with natural gas quality will be injected annually in the gas network of network manager Westland Infra, and supplied to the transport sector, accounting for around 30 million km of road transport per year. In the future, the biogas upgrading installation can easily be made suitable for the production of high-calorific gas (H-gas).
3-stage membrane separation
Bright Biomethane uses proven 3-stage membrane separation technology to separate the present carbon dioxide (CO2) from the methane (CH4). This 3-step technology, which circulates the permeate of the different stages, ensures that the highest possible efficiency (>99.5 percent) is achieved with the lowest possible methane slip (<0.5 percent). This is a significantly lower methane slip compared to other separation technologies for the upgrading of biogas to biomethane.
