Decentralised sewage sludge utilisation for the generation of thermal energy

enercity Contracting GmbH has also opted for the disposal path of thermal sewage sludge utilisation: At the beginning of 2020, sludge2energy GmbH – a joint venture of HUBER SE and WTE Wassertechnik GmbH – was commissioned as general contractor with the planning and turn-key construction of a mono-incineration plant for sewage sludge in Hanover-Lahe.

Both mechanically dewatered and externally fully dried municipal sewage sludge are to be utilised in the plant. The total capacity is 30,000 tonnes of dry matter per year. This corresponds to a volume of about 130,000 tonnes of dewatered sewage sludge with a dry matter content of about 22 % DS.

The main process components of the plant are a HUBER Disc Dryer RotaDry®, the S2E Fluidizer –  a stationary fluidized bed furnace – including boiler, a backpressure steam turbine for optimum power utilisation with maximum flexibility in plant operationand a flue gas cleaning system, which ensures full compliance with the permissible emission limits.

The premise in the planning and realisation of the Hannover-Lahe plant is, in addition to thermal and electrical self-sufficiency, the maximum possible extraction of environmentally friendly generated heat, from which approx. 5,000 households are to benefit via the regional district heating network.

The planning phase has already been completed and the construction work is currently being carried out. Regular operation of the plant is scheduled to start as early as the turn of the year 2022/2023.

Plant features:

• Optimised, maximum district heat extraction
• Adapted contaminant management
• Thermally and electrically energy self-sufficient