Planning the best strategy for sludge treatment and disposal operations

Abstract

Sludge treatment and disposal operations on a local or regional basis need careful planning to ensure that the strategy undertaken is environmentally acceptable, reliable and cost-effective. A database of information is needed for the area concerned which may include up to 100 wastewater treatment plants of varying size. Sludge quantities and quality have to be assessed now and into the future. Disposal options for sludge have to be analysed by an environmental assessment approach which studies the accessibility of all outlets, environmental legislation and attitudes of collaborating agencies and the public at large. Other wastes which may compete with sludge for disposal outlets must be considered. Outlets which involve recycling and beneficial use of sludge are advantageous but may not be practical. Sludge treatment must be evaluated in relation to the disposal options available. Sludge treatment centres, treating sludge from several surrounding wastewater plants, may be required especially if thermal drying or incineration are likely options. Economic evaluation has to consider capital and operating costs of sludge treatment and transport and other costs associated with disposal. The paper discusses how to evaluate all the information and options and find a suitable sludge treatment and disposal strategy.