Where to put the sewage sludge?
The disposal options for sewage sludge have become increasingly uncertain in recent years. Landfilling has not been permitted since 2005, and agricultural sewage sludge recycling is also no longer permitted in all federal states due to concerns about pollutants entering the soil and plants and thus the food chain.
Disposal prices also vary considerably depending on the region and disposal method (e.g., co-incineration in coal-fired power plants and cement works, as well as agricultural recycling).
This raises the question for many municipalities of how to proceed. Which disposal method is secure in the long term, environmentally friendly (soil, water, air, traffic), inexpensive, and independent of third parties?
The planned thermal recycling of sewage sludge at the Mainz central sewage treatment plant (see aerial photo with location marked) will make the plant independent of electricity and natural gas supplies and the annually increasing, market-dependent disposal prices. By adding external sludge from partners (e.g., Stadtentwässerung Kaiserslautern AöR, Abwasserzweckverband "Untere Selz"), the plant's own electricity generation will be further increased in order to cover the entire energy consumption of the sewage treatment plant in Mainz independently and even CO2-neutrally.