The objective of sewage sludge treatment is to prepare sewage sludge (a side product of waste water treatment) for environmental friendly disposal at minimum costs.

In sewage treatment about 13 % of the total annual costs for waste water treatment are due to sewage sludge disposal.

Although the prevention of sewage sludge is highly desired but practically not possible sludge minimization associated with cost savings have high priority.

The temporary use of flocculants and the imminent revision of fertilizers and sewage sludge legislation in Germany have led to the controversial discussion of sustainable utilization of sewage sludge for many years.

The debate concentrates on the bivalent role of sewage sludge as nutrient storage but also as pollutant sink, since sewage sludge is a valuable resource for nutritive substances, phosphorus in particular.

Therefore, phosphor as being a finite and non-substitutable material takes a special role. The use of appropriate techniques makes the recovery of phosphor from sewage sludge as well as from the sludge incineration ash viable.

Sludge treatment

Efficient and process-optimized sludge treatment for safe management and a cost-effective recycling or disposal.

  • Analysis of the specific context
  • Optimization of existing sludge treatment plants
  • Planning of the plant in:
    • Conditioning
    • Aerobic and anaerobic stabilization
    • Sludge thickening and dewatering
    • Thermal sewage sludge drying
    • Solar sewage sludge drying
    • Sewage sludge incineration
    • Sewage sludge composting
    • Sludge disintegration
    • Other disposal
  • Energetic and process optimization
  • Special sludge applications
  • Cogeneration installations
  • Construction and remediation of anaerobic digesters and gas storage facilities
  • Sewage sludge disposal concepts
  • Establishment of partnerships for sewage sludge treatment and disposal
  • Service tenders for sewage sludge treatment and disposal
Thermal sludge treatment

The lack of acceptance for the utilization of sludge in the agricultural sector and the landfill ban lead to the thermal recycling of the sewage sludge.

  • The drying of sludge reduces the water content. This eases the transportation and creates favorable conditions for the self-sustaining combustion.
  • Fluidized-bed incineration, developed for mono incineration of sewage sludge, provides an almost pollution-free thermal treatment.
  • Existing coal-fired power plants as well as the cement plants and waste incinerators are limited for co-incineration of sewage sludge.


Thermal sludge treatment

A former landfill will be the location of the new Sludge Treatment Facility (STF) for the region of Hong Kong