Retrofit is designed to optimize energy recovery from sewage sludge.
Biogas plant manufacturer Weltec Biopower of Germany is offering a retrofit package for anaerobic sludge treatment, designed to optimize the energy potential of sewage plants that serve communities of from 20,000 to 30,000 people.
Weltec says such sustainable sludge treatment strategies are vital, especially since some regions are discontinuing the use of sludge as fertilizer.
Weltec’s anaerobic sludge treatment approach follows the preliminary treatment of the wastewater and the removal of pollutants. Anaerobic sludge fermentation, during which the sewage gas develops, is the process step that offers a particularly high energy utilization and savings potential for the sewage plant, the company says.
“With this possibility to generate power for their own consumption, sewage plants can cut their energy costs by up to a quarter,” says Hajo Schierhold, sales manager of Weltec Biopower. “Additionally, the heat produced by the cogeneration unit can be used directly and inexpensively to heat buildings and the digester in order to accelerate the entire fermentation process,” adds Schierhold.
Weltec says the fermentation also reduces the amount of sludge, which ultimately results in lower sludge disposal costs. “This reduces the sewage plant operating costs even more,” says Schierhold.
The company says the reduction helps avoid harmful greenhouse gas emissions that diffuse into the atmosphere during aerobic sludge stabilization. The unit’s digesters are designed to provide intermediate storage of the fermentation gas as an energy source for the cogeneration (CHP) supply, according to Weltec. Carbon compounds are converted to methane in the stainless steel bio-reactors, according to the company.