Sewage sludge disposal

In Germany approximately 2 million tons of sewage sludge on a basis of total solids (TS) are generated every year. The disposal of this huge amount of problematic material is elaborate and costly. According to a publication by the German Federal Environmental Agency (QUELLE!!) in 2010 about 30% of the sludge was distributed on agricultural land, 53% was incinerated by various means and around 17% was used in land filling.

The resulting costs are enormous: Total costs including mechanical dewatering and transportation are estimated in the range between 120€ and 375€ per ton(TS) are estimated for agricultural use and between 180€ and 400€ per ton(TS) for mono-incineration.

These high costs, especially for thermal utilization, are a direct result of the high water content due to inferior dewatering properties of the sludge, yielding a low heating value and high transportation volume. The cost structure is expected to aggravate over the next years, due to the fact that use of sewage sludge is prohibited in organic farming and a banning for conventional farming is under severe consideration. A total of 9 million tons (TS) per year of sewage sludge requires disposal throughout the European Union today.

The CS-HTC90™ technology by carbonSolutions is particularly suitable for the treatment of sewage sludge of all kinds. With our technology the sludge is transformed into coal slurry. In stark contrast to the original sludge this slurry can be dewatered purely mechanically and without using additives to a solid content up to 70%. After treatment with carbonPure the processed water is simply returned into the waste water treatment plant.

Advantages:

  • CS-HTC90™: sewage sludge treatment in 90 minutes only
  • Complete sterilization
  • Excellent dewater ability
  • Reduction to only a quarter of the original mass
  • Positive heating value
  • Easy to integrate into an existing waste water treatment facility
  • Small area footprint
  • Phosphate recovery still possible
  • Economically superior to alternative processes