Sludge dewatering and disposal practices for small activated sludge wastewater treatment plants

Sludge dewatering is a decisive step in the reduction of waste sludge Volume, thus considerably affecting total sludge treatment and disposal costs. The construction of sludge dewatering facilities in small WwTPs though, is generally not cost effective. In this paper some experimental evidence is presented, that waste sludge dewatering in small WwTPs of the activated sludge-extended aeration type, can be effectively achieved by a centrifuge type Of equipment withdrawing sludge directly from the aeration tank; an economic evaluation of the possibility to employ a transportable type of similar equipment mounted on a truck, to serve a number of small WwTPs located in remote or isolated areas is also presented and discussed.