The sludge undergoing anaerobic decomposition in the digesters is not completely decomposed but is converted into a more environmentally-friendly material.
During digestion, water is produced such that the sludge is too diluted to transport to sites for further treatment.
In order to concentrate the sludge, the sludge is dewatered with the use of eight belt filter presses and three centrifuges (see picture) that reduce sludge volume by an order of 5 to 7 times enabling the conveyance of the sludge to compost production sites.
See the chart below, which describes the efficiency of the sludge dewatering process.
Sludge dewatering centrifuge
Sludge dewatering efficiency during the last five years
[Legend:] Intake to dewateringOutlet from dewatering
[Y axis] Tons/year