en.Wedoany.com Reported - A newly operational anaerobic digestion plant in southern Spain has installed the country's first digestate pasteurization system, supplied by HRS Heat Exchangers. The system adds a dedicated treatment step for the digestate, helping the operator comply with European animal by-product regulations and preparing the material for use as agricultural fertilizer.
Construction of the facility began in 2025. At full capacity, it is expected to produce 58 GWh of biomethane annually, which will be injected into Spain's national grid, with annual output estimated to meet the energy needs of approximately 11,000 households.
The plant processes agricultural and livestock residues, including olive pomace, whey, pig manure, and chicken manure. Anaerobic digestion converts these feedstocks into renewable gas, but also produces nutrient-rich digestate that can be returned to farmland. Because the input materials contain animal by-products, the digestate must undergo pasteurization before agricultural use, as required by European Regulation (EC) No 1069/2009, to reduce the risk of pathogens spreading to soil, crops, or livestock.
The HRS system can process up to 220 metric tons of digestate per day. Three storage tanks support continuous operation, with feeding, pasteurization, and emptying carried out in separate vessels. Corrugated double-tube heat exchangers raise the digestate temperature to 167°F, and the system is designed to handle variations in feed temperature and consistency—an important consideration for facilities processing multiple organic waste streams.
To reduce the energy required for pasteurization, the system transfers heat from the treated digestate to the cooler incoming material. HRS estimates that the heat recovery unit can reuse up to half of the process's thermal energy, saving approximately 17.5 GWh of thermal energy per year and avoiding around 375 metric tons of CO2 emissions. These figures are supplier estimates rather than independently verified operational results; actual performance will depend on factors such as plant utilization, feed digestate temperature, feedstock composition, and day-to-day operating conditions.
HRS delivered the equipment as a complete turnkey package, including pumps, tanks, control systems, instrumentation, valves, piping, and heat exchangers. According to the company, the customer selected the system after visiting similar installations at anaerobic digestion plants in other countries.
The project reflects the broader expansion of Spain's biomethane sector. HRS reports that Spain had 12 operational biomethane plants in 2024, growing to 25 in 2025, with an expected 46 by the end of 2026, and up to 90 projects potentially coming online in 2027. These projections remain subject to factors such as permitting, financing, feedstock availability, and natural gas grid access. As more projects advance, digestate management will grow in importance for both commercial and regulatory planning.
For farmers, the project may offer an additional route for managing livestock and food processing residues, with the resulting digestate also capable of partially replacing synthetic fertilizers. For developers, effective digestate handling affects operating costs, agricultural partnerships, environmental compliance, and local acceptance, and this installation in Spain provides an early reference case for incorporating pasteurization and heat recovery into large-scale biomethane facilities.
