13. Multiple Reuse of Wastewater: Economic Perspectives

Municipal wastewater is a valuable resource because of its immense nutrient and water reuse potentials though untreated sewage has negative impacts on environment and human health. Properly treated wastewater is, however, safe and can be reused for aquaculture, agricultural and landscape irrigation, industrial processes, etc. In urban areas, reclaimed wastewater are used mainly for non-potable purposes such as recreation centre; sports grounds; school yards; play grounds; edges and central reservations of highways; irrigation of landscaped areas around public, residential, commercial and industrial buildings; and many other allied sites. Partially reclaimed wastewater is used for decorative and ornamental purposes such as fountains, reflecting pools and waterfalls, etc. It is frequently used for fire protection and toilet and urinal flushing in commercial and industrial buildings. In general, low-quality wastewater is widely used for agriculture and aquaculture; high-income countries, however, use treated wastewater for agriculture and landscape irrigation and for different food crops and other crops and nursery products. Currently, industrial water consumption was up to 22% of global water use. Industrial water use in Europe and North America accounted for half of their total water use, whereas in developing countries, it was about 4–12% of national water use, though there is enough scope for increase. Wastewater can be reused within a business itself or between several businesses through industrial symbiosis. The exchange of waste products for the mutual benefits of two or more businesses is also known as industrial symbiosis. It is suggested that the high cost-treated wastewater should be made efficient in use, and there should be appropriate sector-wise use of recycled wastewater. Efficiency of recycling of wastewater implies that allocation of recycled water to different sectors be made in such an optimal way that the overall economic efficiency is maximized. Recycled water is often more expensive than existing water supply. Efficiency of wastewater recycling in developed countries should be increased to reduce the cost of supply of recycled water so that it can compete efficiently with alternative sources of water. In cost-effective analysis, costs included both direct and indirect costs that are associated with the programme together with the intangible positive and negative externalities. An effective planning, management and regulations are necessary for profitable reuse of municipal wastewater for different economic-driven activities.