Sewage Sludge

Aerobic Digestion

A case study from Germany

The stabilization of sewage sludge is a precondition for its agricultural use. FUCHS offers aerobic digestion for far-reaching stabilization.

To relieve the workload on a treatment plant in Germany it was upgraded with aerobic digestion. The design capacity is 20,600 p.e. After thickening the sludge is treated in a closed reactor of approx. 200 m³. Three FUCHS CENTROX Aerators with Foam Control transfer oxygen into the sludge and control the foam – all in one step. 

The process achieves temperatures which are consistently in the upper mesophilic range (up to 50°C). At high temperatures and relatively short detention times degradation of volatile solids exceeds 50 %. Pathogenes and viruses are almost completely eliminated.

The product is stabilized, disinfected sludge, classified as Class A Biosolids, and an excellent organic fertilizer, rich in nitrogen and phosphorus, which is highly welcome in agriculture.



Aerobic Digestion in Germany

  • Treatment objective is stabilized, disinfected sludge (Class A Biosolids), an excellent fertilizer for agriculture
  • Taken into operation in 2009
  • The plant treats municipal wastewater
  • Design capacity is 20,600 p.e.
  • The closed reactor for aerobic digestion has a volume of approx. 200 m³
  • The reactor is equipped with three FUCHS CENTROX Aerators with Foam Control for simultaneous aeration and foam control
  • Temperatures of appox. 50°C are easily achieved
  • Degradation rate of volatile solids of approx. 50 % 
  • Class A Biosolids are used as an agricultural fertilizer
  • The off gas is treated in a biofilter


Aerobic Digestion
Sewage sludge stabilization fast and low-priced at mesophilic temperatures