HUBER modernises sludge drying on Mannheim wastewater treatment plant

First of three HUBER Belt Dryer BT 22 units in regular operation

First line of the HUBER Belt Dryer BT 22 in Mannheim already in regular operation

Back in 2017, HUBER received the order to modernise the sludge drying system of Stadtentwässerung Mannheim on the site of the Mannheim wastewater treatment plant. Three HUBER Belt Dryer BT units of size 22 replace the two older drum dryers.

The modernisation of the sewage sludge drying system not only includes the dismantling of the old drum dryers and the construction of the new belt dryers. The entire heating concept was also adapted to the new medium-temperature belt dryers. The objective of Stadtentwässerung Mannheim is to make the operation of the wastewater treatment plant largely CO2 neutral in the future. The HUBER Belt Dryer BT contributes significantly to this by utilising the waste heat of the combined heat and power units.

The belt drying system supplied by HUBER consists of the following core components:

  • 3 sludge pumps with hopper
  • 3 lines of HUBER Belt Dryer BT 22 with condensation stage
  • Connection of the dryers to the heating network
  • Exhaust air treatment with two-stage scrubber system and biofilter
  • Dry sludge transport with HUBER Screw Conveyor Ro8 T and bucket elevator to the dry sludge silo
  • Complete switchboard and control system for the entire process

After a planning and construction period of approx. 15 months, commissioning of the first line could already be carried out in July 2020.

With the start of regular operation of the first dryer line, the starting signal has been given for the dismantling of the drum dryers in the coming months. After the dismantling is completed, the installation of the two other belt dryers will begin. The commissioning of the two new lines is scheduled for November 2021.

Facts and figures:

  • Site: Mannheim, Germany
  • Size: 3 x BT 22
  • Length of dryer: 25 m
  • Water evaporation: 3 x 1,500 kg/h
  • Throughput: 36,980 t/a (6,328 kg/h)
  • Operating time: 8,000 h/a
  • Drying efficiency: from 26% DR to 90%
  • Heat source: exhaust heat from CHP, 80-90 °C