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From the beginning of the Bronze Age (ca. 3200-1100 BC), domestic wastewater (sewage) has been used for irrigation and aquaculture by a number of civilizations including those that developed in China and the Orient, Egypt, the Indus Valley, Mesopotamia, and Crete. In historic times (ca. 1000 BC−330 AD), wastewater was disposed of or used for irrigation and fertilization purposes by the Greek and later Roman civilizations, especially in areas surrounding important cities (e.g., Athens and Rome). In more recent times, the practice of land application of wastewater for disposal and agricultural use was utilized first in European cities and later in USA. Today, water reclamation and reuse projects are being planned and implemented throughout the world. Recycled water is now used for almost any purpose including potable use. This paper provides a brief overview of the evolution of water reuse over the last 5,000 years, along with current practice and recommendations for the future. Understanding the practices and solutions of the past, provides a lens with which to view the present and future.

The Middle East and North Africa (MENA) region is the driest region of the world with only 1% of the world's freshwater resources. The increasing competition for good-quality water has cut into agriculture's water share but since the use of freshwater for domestic, industrial and municipal activities generates wastewater, the volume of wastewater used in agriculture has increased. About 43% of wastewater generated in the MENA region is treated; a relatively high percentage compared to other developing-country dominated regions. This is because of the perceived importance of wastewater as a water resource and several oil-rich countries with the resources to treat wastewater. The MENA region has an opportunity for beneficial reuse of wastewater but few countries in the region have been able to implement substantial wastewater treatment and reuse programs. The major constraints leading to seemingly slow and uneven reuse of wastewater are: inadequate information on the status of reuse or disposal of wastewater and associated environmental and health impacts; incomplete economic analysis of the wastewater treatment and reuse options, usually restricted to financial feasibility analysis; high costs and low returns of developing wastewater collection networks and wastewater treatment plants; lack of wastewater treatment and reuse cost-recovery mechanisms and lack of Irrig Drainage Syst (2010) 24:37-51 commitment to support comprehensive wastewater treatment programs; mismatch between water pricing and regional water scarcity; preference for freshwater over wastewater; and inefficient irrigation and water management schemes undermining the potential of wastewater reuse. However, some countries such as Tunisia, Jordan, and Israel have policies in place that address wastewater treatment through a range of instruments. Policymakers in these countries consider use of treated wastewater to be an essential aspect of strategic water and wastewater planning and management. With flexible policy frameworks addressing rapid demographic changes and increasing water scarcity in the MENA region, water reuse has great potential if integrated with resource planning, environmental management and financing arrangements.

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Where rapid urbanization is outpacing urban capacities to provide sound sanitation and wastewater treatment, most water sources in city vicinity are heavily polluted. This is of great concern as many of the leafy vegetables eaten raw in the cities are produced in these areas. Following the new WHO guidelines, different non-treatment options at farm, market, and kitchen level were field tested for health risk reduction with special consideration to efficiency and adoption potential. As most households are used to vegetable washing (although ineffectively), an important entry point for risk reduction is the increased emphasis of the new guidelines on food preparation measures. A combination of safer irrigation practices (water fetching, on-farm treatment, and application), the allocation of farmland with better water sources, and improved vegetable washing in kitchens appear to be able to reduce the potential risk of infections significantly, although it might not be possible to reach the ideal threshold without some kind of wastewater treatment. The on-farm trials carried out in Ghana also explored the limitation of other risk reduction measures, such as drip irrigation, crop restrictions and cessation of irrigation under local circumstances considering possible incentives for behaviour change.