Proceedings

Improving sludge treatment whole life cost savings by way of dewatering on satellite sites

Present situation:

• In order to optimise methane production and sludge quality for disposal, the UK has seen a trend towards large, regional sludge reception facilities with some form of Advanced Anaerobic Digestion (AAD) (e.g. with Enzymic or Thermal Hydrolysis pre-treatment).

• These facilities involve significant CAPEX and it is more economically viable to have only a few of these huge capacity sites and bring in sludge from outlying satellite works.

• The transportation costs incurred by such sludge movement are significant and obviously get higher if the sludge is thinner and if the satellite sites are a long way from the AAD plant.

• Some water companies are already using satellite site sludge dewatering to reduce volumes for transport followed by “re-wetting” at the AAD site to give the required feed thickness.