The use of purified waste water for agricultural irrigation

Abstract

Agricultural production is highly dependent on water and is also the largest consumer. In developing countries, on the other hand, rapid urbanisation has led to increased volumes of wastewater being used as a low-cost alternative to conventional irrigation, turning a 'waste' into a new resource to support local agriculture. The re-use of water could thus potentially reduce the need for supplementary applications of inorganic fertiliser. End-users should be informed of the nutrient content of purified water.In the field of purified wastewater, it is not only necessary to make the use of this new resource possible, but also to increase social acceptability by overcoming technical, economic, political and social barriers in order to make greater use possible. Government and research activities should demonstrate the benefits of using purified wastewater and the limitations of doing so, although again such efforts would need to be funded. European geography and climate lead to a disparity in the distribution of water in the EU, in fact we observe a European Union in two gears, a Central Europe rich in water resources and therefore without commercial economic interests in recycling residual water, while a Southern Europe at risk of desertification and interested in a clear, rational and pragmatic regulation of water resources to minimize waste. More than 60% of the water used in Southern Europe is for irrigation, with extraction peaks of up to 80% in some watersheds. The opportunity to use purified urban and industrial wastewater for agricultural irrigation is therefore the most effective strategy to combat drought, a consequence of climate change. Currently, the practice of water reuse is established in only a few Member States and is implemented far below its potential. To facilitate and stimulate the reuse of water for agricultural irrigation, the EU has issued the Regulation on Minimum Requirements for Reuse, setting minimum requirements for purified water quality and monitoring, assigning crucial risk management tasks, and introducing a harmonized approach for the reuse of irrigation water across the EU. The new rules will increase legal certainty in this field, where currently the rules vary widely from one Member State to another.