The WASTE2VALUE research team, affiliated to the PROSIAM group of the Department of Chemical Engineering of the Autonomous University of Madrid (UAM), specializes in the material and energy recovery of biomass waste. The focus is on hydrothermal carbonization (HTC) in line with the principles of the circular economy.
Now in a paper published in the magazine Waste managementthe group has described a process produce a stable carbonaceous materialharmless and suitable as a solid biofuel from the hydrothermal carbonization of pig manure and lignocellulosic biomass.
The Pig manure Since these are wastes that are difficult to treat and highly polluting, their control is mandatory in Spain. Since the hydrothermal co-carbonization process is carried out in the presence of water, a liquid fraction rich in soluble organics and nutrients, especially phosphorus, is obtained, which makes this possible Obtain biogas rich in methane and inorganic biofertilizers.
These results open a new avenue for the conversion of pig manure, which was previously used for composting in agricultural crops and had negative environmental impacts such as eutrophication, nitrification and greenhouse gas emissions.
Furthermore, the resulting compost The added value is low. The solid product of HTC treatment improves the properties of the original waste, increasing carbon content and calorific value while reducing nitrogen, sulfur and ash content.
UAM
Hydrothermal carbonization
The HTC process is carried out at temperatures of 180 °C to 250 °C and with short residence times (5 to 240 minutes) and eliminates pathogenic microorganisms and breaks down emerging contaminants such as: Medications and hormones. In addition, it facilitates the transfer of phosphorus and less thermally stable compounds to the liquid fraction, where they can be recovered, generating high added value products such as biofertilizers and energy (biogas).
The anaerobic treatment of the liquid fraction makes it possible to obtain a wastewater with a low concentration of organic matter, which could be used as irrigation or cleaning water in the same pig farms.
These results confirm that HTC is a promising technology to obtain valuable products from agro-industrial waste while enabling the recovery of water in a closed loop and reducing greenhouse gas emissions, thus promoting a sustainable process.
Thus, the process is sustainable from an energy perspective, reduces dependence on fossil fuels and promotes the production of renewable, clean and environmentally friendly biofuels.
Image of the pilot plant that is developing this new technology/Ángel Fernández Mohedano
In addition, this technology offers a solution for the disposal of pig manure ponds and enables recovery from an energy perspective between 5 and 6 times more energy as the anaerobic digestion of manure without pretreatment.
The resulting biofertilizers have a high content of essential nutrients for plants and a low content of heavy metals, thus meeting the requirements of European Union regulations.
WASTE2VALUE has developed a in collaboration with Arquimea Agrotech HTC continuous reactor for the processing of pig manure, lignocellulosic biomass and other organic waste such as sewage sludge and organic waste and their conversion into products with high added value.
Reference:
de la Rubia, A. et al. “Co-hydrothermal carbonization of pig manure and lignocellulosic waste: A new strategy for the holistic utilization of biomass waste.” Waste management.