Energy recovery from wastewater
Wastewater with high concentrations of biodegradable organic matter offers significant potential for energy recovery. In specially designed reactors, the organic load is broken down through anaerobic treatment processes, generating energy-rich biogas.
To utilize the recovered biogas efficiently and safely for energy, several treatment steps are required. CUSS GmbH provides custom-tailored plant concepts that enable reliable gas treatment, storage, and utilization.
Biogas Cooling and Drying:
Biogas from an anaerobic reactor is typically saturated with water vapor. To prevent condensation and corrosion in downstream system components, the gas is cooled to approximately 4–6 °C. The resulting condensate is separated and can be returned to the inlet of the wastewater treatment plant. This drying process creates the necessary conditions for the safe and trouble-free operation of subsequent gas treatment and utilization systems.
Biogas Desulfurization:
In addition to methane, biogas often contains hydrogen sulfide (H₂S). Even at low concentrations, this substance can be hazardous to health and, due to its corrosive properties, can damage plant components and equipment. Furthermore, combustion can lead to sulfur-containing emissions.
Targeted desulfurization reduces the hydrogen sulfide content, improving gas quality for further use. Depending on the composition of the biogas and the required level of purity, either chemical or biological desulfurization processes are employed.
This protects downstream equipment.
Biogas storage:
Since the timing of biogas production and energy demand within a facility may not always align, biogas storage systems act as a buffer between production and utilization. They allow for the supply of gas according to demand and ensure the most continuous supply possible to connected consumers.
Storage can be implemented directly via a membrane roof on the anaerobic reactor or through separate storage solutions. Examples include gas bags or double-membrane storage systems. The choice of storage solution depends on the volume of gas produced, the consumption profile, and site-specific structural conditions.
Biogas flares:
These ensure the controlled combustion of excess biogas when it cannot be immediately utilized—for instance, during maintenance, operational disruptions, or overproduction. In this process, the methane contained in the gas is primarily oxidized into carbon dioxide and water, thereby avoiding the more climate-damaging impact of direct methane release.
Consequently, a biogas flare is an essential component of the safety concept, contributing to both operational reliability and environmental protection.
Boilers and combined heat and power (CHP) units:
Following the necessary treatment, biogas can be used in a variety of ways. It can be used in industrial boilers to generate heat, while combined heat and power (CHP) units can simultaneously produce both electricity and heat.
This allows the facility’s energy requirements to be met, either partially or entirely, using the biogas produced on-site.
Alternatively, once the biogas has been processed to meet the required quality standards, it can be injected into the public gas grid. Determining which utilization option is both economically and technically viable depends on factors such as the volume of gas available, the facility’s energy needs, and local conditions.
CUSS GmbH develops customized, comprehensive solutions for biogas upgrading and energy recovery. We coordinate every component—from cooling, desulfurization, and storage to final energy utilization—to ensure a seamless system. This enables the efficient use of existing energy potential, a reduction in operating costs, and the sustainable conservation of resourc
