Increasing demands on the quality of wastewater, growing concerns regarding the disposal methods used to date, and the need to retrieve raw materials from wastewater currently provide the framework for the planning of sustainable treatment technologies.

In the primary clarification stage, sewage sludge accrues when organic substances are degraded. This has to be purified, recycled or disposed of but there are currently no competent standard procedures for further processing. In some counties the disposal of sewage sludge is carried out at landfills, for example, whilst in others some of the sludge is used as a biological fertiliser in agriculture.

As an unrestricted disposal of sludge is no longer possible at every location and the pollution levels of the “fertilizer” are a cause for environmental concern, the demand for efficient and sustainable concepts for sludge treatment is increasing.

Regardless of subsequent disposal methods, it is advisable, from an economic point of view, to prepare the sludge for downstream processes. Separation procedures, in which solids are removed from the water phase, play a central role. Sludge treatment is necessary to reduce the volume and mass of sludge which accrues in the wastewater clarification process and to improve the possibilities for further utilisation. The effectiveness of the separation process has a decisive influence on the volume of sludge to be transported and disposed of.

With these aspects in mind, Bilfinger Water Technologies develops a wide range of systems and machines for sludge thickening and dewatering processes.