Polluted water renovation for reuse: Recent biotechnological advances applicable in hot arid regions

Both sewage and industrial wastewater are important resources in hot arid regions provided they can be economically purified to meet the requirements of reuse. Conventional treatment technology involves a sequence of physical, biological and physico-chemical process steps designed for effective pollutant removal in temperate climates where, even there, overall process performance is rarely optimal. Frequently, the reason for this is that the process microbiology involved in biotreatment is little understood and very largely ignored in spite of the fact that it is the biotreatment step that is responsible for the removal of the bulk pollutant load. This contribution will consider recent advances in process microbiology that will permit more effective biotreater operation at high ambient temperatures and the way in which these advances can be incorporated in the design of biotreatment processses for the effective and economic purification of sewage and industrial wastewater, so as to allow their sensible reuse, and of waste sludge, so as to allow safe disposal on cultivated land. Emphasis will be placed particularly on noxious chemical pollutant and pathogenic organism elimination during biotreatment.