Wastewater Treatment Plant Biogas for Spark-Ignited Engines
The modern wastewater treatment plant’s processes are uniquely wellsuited for generation of on-site power, but currently only a minority of eligible plants do so. The processes in a wastewater treatment plant can be viewed simply as cleaning wastewater to be returned safely to the environment. During treatment, waste streams such as biogas are created that can be converted into useful energy again. Biogas fueled spark-ignited engine generators present wastewater treatment plants with an opportunity for operational
cost savings as well as environmental solutions to growing energy and
carbon concerns.
Synergies between WWTP and Spark-Ignited Engine Generators
High utilization of the waste streams illustrated above
and proper sizing of the power plant can lead to total
system efficiencies that exceed 90%.
1. Biogas (a by-product of anaerobic digestion) is delivered to the generator set as fuel.
2. The generator creates electricity for the plant’s onsite needs or for export to the local grid.
3. Engine heat can be recovered via the engine’s cooling circuit or exhaust gas and converted to hot water or steam for the digester. This heat can keep the digester at its optimal temperature for increased biogas production.
4. Recovered generator heat can also be used to dry the remaining digester solid for plant fertilizer, which can be sold for additional revenue for the WWTP.