Management of waste sludge in pasakoy advanced biological wastewater treatment plant

Abstract

his study discusses the management of sludge that is generated as a result of the treatment process in Pasakoy Advanced Biological Wastewater Treatment Plant (PABWWTP) that has a daily urban wastewater treatment capacity of 200 000 m(3). The excessive sludge generated through the process is stored in the sludge storage tank over the return line and is taken from process tanks if required. Furthermore, the excessive sludge can also be transferred directly to dewatering unit without being taken into the storage tank. This enables transforming the sludge with dry solid rate of 1% average in the system into 25% sludge cakes and transferred to sludge drying unit. In this unit, the biological sludge with 25% of dry material content is turned into 98% cake, granules or dust, a daily disposal amount of 200 t of harmful sludge is turned into 50 t of useful material and the dried sludge can be used as secondary fuel in cement factories. Consequently, the problems concerning transporting and storing the wet wastewater sludge which is both an environmental and economic problem in many ways are avoided while a new dried and valuable product is maintained to be used as fertiliser or fuel.