ENTEG seminar by Prof G.J.W. Euverink, entitled: "CADOS"

Abstract

Filtration of untreated raw domestic waste water leads to a residue that contains small, fiber-like material. This material consists for approximately 60% of cellulose that originates mostly from toilet paper.
The principle of a biological waste water treatment plant (WWTP) is to convert dissolved chemical compounds (C, N, O, P, S) into biomass (=sludge) that can be removed from the water. Part of the carbon and nitrogen present in the waste water is emitted as CO2 and N2, respectively. The excess sludge is collected, dewatered and incinerated or converted in an anaerobic digester into biogas (CH4+ CO2).
However, the dewatering of sludge is energy and chemical intensive and not very efficient. The final product still contains 70-80% water. Transportation is therefore also inefficient. In total, on average 50% of the operational costs of a WWTP is due to the costs involved in sludge treatment. In the CADOS (Cellulose Assisted Dewatering Of Sludge) project we use the fine-sieve fraction of untreated domestic waste water as an aid in the dewatering process of sludge.