Wastewater treatment plant – Alcoy (Spain)


A Rank® HTC1 system is installed in the wastewater treatment plant (WWTP) of Alcoy (Spain). The unit uses the waste heat from the cogeneration engines, producing clean electric power and heat to improve the performance of the anaerobic digesters.

The wastewater treatment plant

The wastewater treatment plant (WWTP) of Alcoy (Alicante, Valencian Community, Spain), operated by the company FACSA, is designed to treat a daily flow of 23,976 cubic meters. It serves the municipalities of Alcoy and Cocentaina, covering a population of around 97,000 inhabitants.

The total installed electrical power is approximately 1,600 kW. In 2017, the average daily flow received was 17,623 cubic meters.

Electric generation from biogas

The anaerobic digestion of sewage sludge is a sludge stabilization system that is used in the elimination of a significant part of the volatile fraction of the sludge. The unstabilized sludge generates odors due to putrefaction and the risk of proliferation of infectious bacteria.

During this process, biogas is produced, which is composed by 65% of methane. This biogas can be used within the plant itself in a cogeneration system to produce thermal energy and electricity (for self-consumption or to be injected into the electricity grid).

The installation

The Alcoy WWTP uses biogas to feed an internal combustion engine, generating electricity. The exhaust gases from this engine are used to activate a Rank® HTC1 unit, which generates additional electrical energy and useful heat in the form of water at 70 ° C for the controlled process of anaerobic digestion.