Major among the motivational factors for wastewater recycle/reuse are:
Opportunities to augment limited primary water sources
Prevention of excessive diversion of water from alternative uses, including the natural environment
Possibilities to manage in situwater sources
Minimization of infrastructure costs, including total treatment and discharge costs
Reduction and elimination of discharges of wastewater (treated or untreated) into receiving environment
Scope to overcome political, community and institutional constraints.
Read Also : What is Wastewater and Sources of Wastewaters
Reuse of wastewater can be a supplementary source to existing water sources, especially in arid/semi-arid climatic regions.
Most large-scale reuse schemes are in Israel, South Africa, and arid areas of USA, where alternative sources of water are limited.
Even in regions where rainfall is adequate, because of its spatial and temporal variability, water shortages are created. For example, Florida, USA is not a dry area, has limited options for water storage, and suffers from water shortages during dry spells.
For this reason wastewater reuse schemes form an important supplement to the water resource of this region.
Costs associated with water supply or wastewater disposal may also make reuse of wastewater an attractive option.
Positive influences on treatment costs of wastewater and water supplies, and scopes for reduction in costs of head works and distribution systems, for both water supply and wastewater systems has been the motivation behind many reuse schemes in countries like Japan.
Reuse is frequently practiced as a method of water resources management. For example, depleted aquifers may be “topped-up” by injection of highly treated water, thus restoring aquifer yields or preventing saltwater intrusion (in coastal zones).
Avoidance of environmental problems arising due to discharge of treated/untreated wastewater to the environment is another factor that encourages reuse.
While the nutrients in wastewater can assist plant growth when reused for irrigation, their disposal, in extreme cases, is detrimental to ecosystems of the receiving environment.
In addition, there may be concerns about the levels of other toxic pollutants in wastewater.
Concern about water supply or environmental pollution may emerge as a political or institutional issue. Community concern about the quality of wastewater disposed to sensitive environments may lead to political pressures on the water industry to treat wastewater to a higher level before discharge that can be avoided through reuse of wastewater.
Institutional structures may also provide incentives for reuse. Because responsibility for different parts of water use and disposal system may rest with different organizations, a water utility may also be faced with standards of service set in agreements with other industry bodies.