Guidelines For Drinking-Water Quality Management For New Zealand – Chapter 14: Treatment Processes Filtration And Adsorption

Conventional wastewater treatment technologies improve the quality of wastewater discharged into the environment and restrain polluted waters from contaminating other available clean water resources. However, these treatment technologies do not make wastewater fit for further beneficial uses in communities closer to the points of generation. Innovative and advanced technologies that can further improve the quality of wastewater are needed to overcome this limitation of conventional technologies, and to promote widespread adoption of recycle and reuse practices. Advanced treatment processes can be biological processes, physicochemical processes, or a combination of both (hybrid processes). Biological processes to remove nutrient pollutants such as nitrogen and phosphorus, provide the platform for further wastewater treatment to reusable quality. Physicochemical processes such as deep-bed filtration, floating media filtration, and membrane filtration, play a major role among treatment technologies for water reuse. Membrane filtration has significant advantages over other processes since they produce high quality effluent that requires little or no disinfection with minimum sludge generation. The hybrid processes attempt to obtain the benefits of both biological and physicochemical processes in one step.

In many semiarid and arid countries, water is now becoming an increasingly limited resource and managers are forced to take into account sources of water that may be used economically and efficiently to encourage further development. Simultaneously, with the population increasing at a high rate, the requirement for increased production of food is apparent. The prospective for irrigation to increase both the agricultural productivity and living standards of the poor has long been acknowledged. Irrigated agriculture occupies nearly 17% of the total arable land in the world but the yield from this land includes about 34% of the world total. This perspective is even more distinct in arid areas like the Near East Region, where only 30% of the cultivated land is irrigated but it yields around 75% of total agricultural production. In the same area, more than 50% of the food necessities are imported and the increased rate in demand for the food surpasses the rate of an upsurge in agricultural production (Tunney et al., 2000).