Partner Sought for Pilot Project in Sewage Sludge Drying

The drying of sludge has once again become of interest in many industrial companies due to increased disposal costs. Municipalities are also looking for new disposal routes due to a new regulation that will more strictly regulate sewage sludge disposal in the near future.

Drying of sewage sludge

The drying system manufacturer Harter from Stiefenhofen in the Allgäu region has its origins in the drying of industrial sludges and has already carried out extensive test series with sewage sludge in the past in order to prepare itself for this new market. For smaller sewage treatment plants that favor decentralized treatment of their sewage sludge, energy-saving sludge drying using a heat pump is an ideal answer. Transport costs and, as a result, traffic and environmental pollution would thus be significantly reduced. In some cases, the sludge can also be used for other, possibly cost-reducing purposes after drying.

Heat pump technology state-funded

Drying systems from Harter are designed both for batch operation and as a continuous solution. The capacities here range between 1 – 20 tons of sludge per day. Harter is currently looking for a partner for a pilot project in the field of municipal sewage sludge drying. Due to the CO₂ savings, there are state subsidies for the energy-saving Harter dryers.

Basic information on sludge drying

With condensation drying based on heat pumps, water-containing sludges and substrates of all kinds are dried at low temperatures and with extremely dry air in an energetically closed system. This process is used for filter-pressed sludges, which after pressing still have a water content of
approx. 60 – 70%:

_ Weight reduction of up to 60%
_ Volume reduction of up to 60%
_ Homogeneously dried sludge with DS content 80% – 90%
_ Drying temperatures between 40° – 50°C

Economic opportunities

_ Reduction of disposal costs by up to 60%
_ Possibly classification in a better category
_ Possibly recycling of existing recyclables possible
= new source of income