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Wastewater biogas - sludge as a sleeper source of energy

Friday, 16 April 2021

On 13 April 2021, the European Biogas Association (EBA) released a paper detailing the potential of biogas from industrial wastewater.

The proposition of waste to biogas is attractive on many sustainability fronts, including reduced energy consumption of treatment facilities, sludge management, and job creation.

The study put the total potential of industrial wastewater biogas at 142 TWh a year in Europe. This includes treating the wastes of the spirits, biodiesel, pulp and paper, beer, vegetable oils, ethanol, meat, and cheese sectors.

Biogas from wastewater had not previously been considered in European biogas production projections to 2050, estimated to be around 1-1.3 TWh per year. As such, industrial waste biogas could raise this figure by more than 10%.

Current methods of processing wastewater for safe discharging involve aeration, which has a high energy footprint and produces large amounts of sludge. The EBA paper notes that biogas production from the same waste stream would utilize an anaerobic pre-treatment step, reducing the sludge produced (by up to 80%) and overall energy requirements (by up to 75%).

The EBA has suggested that biogas from industrial wastewater be strongly considered in upcoming EU legislation, with the objectives of the Urban Wastewater Directive and Methane Strategy being aligned with the EU clean energy agenda.

According to Vasilis Diamantis (Chair of the EBA working group Wastewater), “AD (Anaerobic Digestion) penetration to European SMEs is expected to boost the environmental technology market, create new job positions and significantly decrease greenhouse gas emissions. Economic incentives are more than necessary combined with environmental legislation and social awareness measures. Technology providers should develop sector-specific solutions and ensure economies of scale for decentralized energy production. These are real challenges for the future.”

Biomethane from wastewater?

While biomethane is not mentioned in the paper, the logical extension of wastewater biogas is upgrading to biomethane, particularly if the gas needs to be transported via pipeline. 

Biomethane production from wastewater treatment plant sludge already occurs in France - the GRDF recorded 76 GWh of GOs for such biomethane being issued in 2020, more than doubling the previous year GO issuance of 37 GWh. 

Nevertheless, as the EBA has suggested, there is significant room for growth, with wastewater biomethane GOs accounting for a little over 3% of total biomethane GO issuances in the country.

Bioenergy News

European Biogas Association - press release