Critical attributes and considerations for selecting irrigation systems for wastewater

With increasing global population, the gap between the supply and demand for water is widening and poses a threat to human existence. In the face of water scarcity, urban wastewater is increasing in its attention as an alternate water source for crop production. However, several challenges such as toxicity hazards, salinity build-up and health concerns have been identified with the use of wastewater in agriculture. There are several technological solutions that can help ameliorate or lower the level of contamination associated with using wastewater for irrigation. This paper explores the use of some irrigation technologies to abate the toxicity and health concerns associated with wastewater irrigation. The paper identifies some decision parameters for the selection of identified irrigation technologies and subjects them to multi-criteria decision analysis (MCDA) to rank them based on the level of exposure of the crop and irrigator/field worker to contamination among other relevant criteria. This paper validates that limiting the contact of the wastewater with the edible parts of the crop, especially for leafy vegetables, can minimize contamination to the crop and field workers. Though not totally without constraints, the identified irrigation methods present prospects for a cleaner and more sustainable production with regard to wastewater usage in agriculture. Sub-surface drip irrigation systems were identified as the best irrigation system for filtered and treated wastewater followed by surface drip and pitcher irrigation. Irrigators can fall back on some of these identified methods for wastewater application for sustainable crop production and maximized food safety.