Innovative technology scale-up for the control and automation of codigestion in WWTPs to produce green energy on demand

PROJECT DESCRIPTION

BACKGROUND

Most greenhouse gas (GHG) emissions come from energy production. For that reason, renewable energies must play a fundamental role in solving the climate change problem. If these technologies become an economic and technically-viable alternative to conventional fossil energy resources, a large-scale reduction of GHG emissions would be achieved. On the other hand, millions of tonnes of waste are produced each year by the agriculture and food sectors, and most of this is potentially biodegradable. These wastes have, in many circumstances, a high-water content, which increases their freight costs and makes their treatment difficult. The co-digestion of these wastes with waste water treatment plant (WWTP) sludge is an alternative treatment with important possibilities, since its use transforms waste into by products and biogas, a renewable energy.

OBJECTIVES

The main objective of the LIFE ECOdigestion 2.0 project is the real-scale demonstration of an innovative technology for the automated control of waste dosage in anaerobic digesters of WWTPs, to produce on-demand biogas with sewage sludge and agri-food waste. The project team will also maximize the biogas production and the waste treatment capacity. The technology is based on a previous project, ECOdigestion (LIFE13 ENV/ES/000377), which developed and demonstrated a prototype-scale version of this innovative technology.

The project contributes to implementing EU Directive 2009/28/EC on the promotion of the use of energy from renewable sources, Waste Framework Directive (2008/98/EC), EU Circular Economy Action Plan, and the Roadmap to a Resource-Efficient Europe. In addition, it is in line with EU and international climate change mitigation goals, and the Spanish Waste Management Plan (2019-2022).

RESULTS

Expected results:

Scale-up the tool for automatic co-digestion in WWTP of Quart-Benger (Spain) with agri-food and manure to obtain energy on demand, with feeding recipes generated and updated every 15 min;

Achieve targeted biogas production after the implementation of automated dosage of co-substrates;

Increase by 192% the amount of manure and agri-food waste that can be treated, which means 85 191 t during the demonstration at real-scale;

Obtaining 14% more biogas with the co-digestion compared to digestion of each substrate separately;

Improve the stability of the co-digestion process under different operational conditions with various co-substrates (keeping the acidity/alkalinity ratio between 0.05-0.15);

Valorise 27 375 t/year of agri-food waste and 102 200 t/year of manure by changing their destination from incineration, agriculture, compost and landfill disposal to co-digestion. This implies: i) avoiding the emission of GHG, about 7 900 and 16 442 CO2eq in agri-food and manure co-digestion demonstration respectively; ii) total annual methane production with agri-food waste of 2 729 471 Nm3 and 951 400 Nm3 with manure, which means 14 571 MWh and 7 540 MWh, respectively;

Four qualified full-time jobs consolidated and one created during the project (specialised technicians);

Regarding the EU-level impact, the implementation of the tool in all WWTPs with anaerobic processes (5 477 WWTPs) would imply an energy production of around 58 000 GWh/year. In addition to this, an annual reduction of GHG of 66.2 Mt CO2 and 17.1 t NOx, and of gases that promote acid rain in 23.7 t SO2 would be achieved.