ABSTRACT
Provision of adequate and clean potable water is an essential requirement for a healthy community. At the same time, collection of this water after it has been contaminated through domestic or industrial use, followed by its treatment at a wastewater treatment facility, is necessary to prevent pollution of rivers, lakes and the seas. Undertaking these treatment activities is costly with a potentially high energy input and associated greenhouse gas emissions. In addition, both drinking-water treatment and wastewater treatment produce sludge as an end-product that historically has been disposed of to sea or to landfill. This chapter describes modern techniques for treating potable water and wastewaters to the high standards today’s society demands, while emphasising the opportunities for energy reduction and cost savings. It also considers the options available to recover energy and nutrients from sludge thereby allowing complete recycling of this material. Application of novel treatment technologies now permits us to consider sewage as a resource and not a waste.
