Wrocław Sewage Treatment Plant uses the energy potential of sewage sludge and minimizes the use of water by utilizing purified sewage.
Everyday Wrocław Wastewater Treatment Plant collect and treat approximately 120 000 m3 of sewage. Eliminated pollution from sewage have a big energetic potential, which is used in two stages. During pollution processing, the so-called sewage sludge, is subjected to fermentation, thanks to which biogas is obtained. It is a "green fuel" that is used to the production of electricity and heat for the needs of the treatment plant. The energetic potential remaining in the pollutant stream is used by the cement plant, which receives dried sludge and uses it as a fuel. This is an example of industrial symbiosis, where waste from one plant is a raw material for another.
Additionally, the stream of purified sewage, thanks to its high quality is used for the plant’s own needs. Wastewater treatment plant has a high demand for cooling water for the dryer and process water for regular cleaning of mechanical equipment. Using the “produced” outlet stream by itself for applications where quality of water is not as high as drinking water, reduces the demand for tap water. And this have an impact on lower intake of fresh water.
The beneficiary of presented solutions are indirectly all Wrocław residents, because these practices affect lower cost of sewage treatment.
Unknown/depending on the size of wastewater treatment plant.
Evidence of success
Through the use of energy potential in the sewage sludge stream, the treatment plant is 70% self-sufficient in energy.
Potential for learning or transfer
Such technological solution can be implemented in majority of wastewater treatment plants. The return of investment expenditure is the faster the more organic matter is delivered to the system. If a wastewater treatment plant produces small amount of sludge, it is possible to collect organic waste, which also undergo methane fermentation.