Successful commissioning of the first HUBER RotaDry® disc dryer in Hanover-Lahe

The sewage sludge recycling plant in Hanover-Lahe will go into operation after successful hot start-up and optimisation: the plant, which has been equipped with two HUBER RotaDry® 2050 M disc dryer units, now recycles sewage sludge from the surrounding sewage treatment plants every day and supplies 5,000 households with district heating from a renewable source. The opening ceremony for the sewage sludge recycling plant took place on 6 July in the presence of Dr. Manfred Schüle (Managing Director of enercity contracting GmbH), Dr. Susanna Zapreva (Chief Executive Officer of enercity) and Hanover’s Mayor Belit Onay.

Recycling 130,000 tonnes of sewage sludge per year

The primary goal of the plant, which was planned and built by sludge2energy GmbH as the general contractor, is to recycle around 130,000 t of drained sewage sludge per year. A further goal is the return of the valuable and finite raw material phosphorus from the sewage sludge ash. As a result, enercity contracting GmbH is already making it possible today to comply with the recovery of phosphorus from wastewater, legally required as of 2029.

The 2 HUBER RotaDry® disc dryer units in Hanover-Lahe
The 2 HUBER RotaDry® disc dryer units in Hanover-Lahe

HUBER supplied key plant components

With the two disc dryers, HUBER supplied two key components for the Hanover-Lahe recycling plant. The sewage sludge delivered by various sewage treatment plants is supplied to the respective dryers by a bunker crane and piston pumps. The two HUBER RotaDry® 2050 M disc dryers dry the sludge from an average of approx. 22% DR to approx. 40% DR.

The partially dried sewage sludge is then autothermally recycled in the subsequent, fluidised bed incineration unit. This means that without additional fuel, the thermal energy from the combustion is sufficient to supply the consumers of the steam system with steam. The installed turbine also makes its contribution to covering the plants own electrical needs.

Plant for sewage sludge mono-incineration with operating facility and delivery hall
Plant for sewage sludge mono-incineration with operating facility and delivery hall

Greener district heating for up to 15,000 citizens of Hanover

In addition to sewage sludge utilisation, the plant also contributes to making district heating in Hanover greener. The sewage sludge utilisation plant supplies up to 15,000 customers within the supply area with regenerative heat.

Consequently, fossil-fuelled heat is substituted in the district heating network. A majority of this extracted heat is provided by the vapour condenser supplied by HUBER. Here, the vapours evaporated in the disc dryers are re-condensed, the district heating water is heated to 90°C and then made available to consumers.

The HUBER start-up team would like to thank all those involved for the constructive cooperation on the construction site and wish everyone smooth plant operation!