The Public Society of Infrastructure and Environment of Castilla y León (Somacil) awarded to the joint venture formed by energy engineering Genia Bioenergy and the builder San Gregorio the contract for the design and construction of a biomethane plant on a plot adjacent to the Cabezón de Pisuerga treatment plant.
The investment by the Public Society for Infrastructure and Environment (Somacyl) is estimated at 4,7 million euros. And it is estimated that the plant is designed to treat 10.350 tons of sludge per year with the expectation of injecting 686.565 cubic meters of green biogas into the network annually.
Sludge from 25 rural treatment plants managed by Somacyl within a radius of 150 kilometers from the location will be transported to the future facilities, so not only those from Valladolid are included, but also those from neighboring provinces, with a double objective. On the one hand, to obtain a better quality fertilizer that is later used as fertilizer in the field and, on the other, to generate that biomethane for marketing.
In any case, as explained by SOMACYL sources, it is not about obtaining an economic benefit from the sale of biomethane, but rather carrying out additional treatment of the sludge that allows the waste from the treatment plants to be managed more efficiently and, in addition, obtaining a fuel. 'green' that can be used in homes or businesses.
The works will begin in January and the plant will be operational before the end of 2023. It will have the capacity to manage 12.500 cubic meters of sludge per year, that is, 34 cubic meters of sludge each day, "avoiding the emission of CO2 and other gases." to the atmosphere," explained the successful bidder, who meant that the 4.622MWh/year of biomethane is equivalent to the consumption of 584 homes with gas heating, cooking and hot water.
According to the statement issued by the UTE, in the first phase, the treatment is based on subjecting the sludge to thermal hydrolysis at high temperatures (between 130 and 180 degrees) and pressure to guarantee its sanitization and in turn facilitate a better degradability and greater biogas production.
Afterwards, the sludge goes to an anaerobic digestion stage to obtain a production of up to 79 Nm³/h of biogas, which will subsequently undergo a purification or upgrading process to eliminate water, CO2 and other compounds, to achieve a biomethane content. greater than 99%, a purity similar to that of the natural gas that will be injected into the supply network, although Somacyl could also use it occasionally as an energy complement to the biomass it uses.
The treatment of sludge through anaerobic biodigestion, the company added in the letter, provides several advantages, such as zero CO0 emissions, the elimination of odors or the recovery of waste as energy.
That is, thanks to the work at the future Cabezón de Pisuerga plant, polluting emissions into the atmosphere will be reduced and richer fertilizers will be obtained, which "largely solves the problem of sustainable management of organic waste," they assessed. .
"The injection of biomethane from wastewater treatment plant sludge into natural gas networks is a procedure that is being carried out throughout Europe, currently promoted by the obligations to reduce CO2 emissions and the geopolitical situation," he said. for its part, the Junta de Castilla y León when it put this project out to tender.
