Sewage Sludge Disposal in Bavaria

Sewage sludge disposal in Bavaria

In northern Bavaria, around 25 municipalities have found a way to turn their sewage sludge into a valuable commodity. E & T Aichaberg GmbH & Co. Trocknungs KG uses a Dorset Green Machines belt dryer to upgrade sewage sludge into high-quality fuel briquettes. Since 2008, the company has dried around 10,000 tons of sewage sludge per year using the Dorset belt dryer.

The liquid material is first pre-dewatered at local sewage treatment plants to a dry matter content of 25 percent. Then, the sewage sludge passes through the dryer, spreading over four floors until it reaches a dry matter content of 90 percent. The heat required for the dryer comes from five wood pellet gasifiers from Burkhardt.

Initially, the dried product had to be crushed into fine particles using a special fine roll technology developed by E & T Aichaberg. However, the results with the sludge pump and dosing head are now so good that no subsequent granulation is required.

The dried sewage sludge is accepted as a substitute fuel by a cement factory and can also be thermally utilized in a sewage sludge mono-combustion plant. The Dorset  belt dryer has proven to be an excellent system for heat production, operating 8,600 hours per year and saving electricity by requiring 80 to 90 percent less energy than comparable systems. Even odors are no problem, as the exhaust air is cleaned with a biological aircleaner, keeping exhaust air values far below legal requirements. An expansion of the dryer capacity is planned in the near future.