Waste-Water Use in Energy Crops Production

1.1 Waste water use in irrigation Water supply and water quality degradation are global concerns that will intensify with increasing water demand; for this reason, worldwide, marginal-quality water will become an increasingly important component of agricultural water supplies, particularly in waterscarce regions. The status of severe water resource shortage determines that new water source must be developed to cope with the deficiency of water sources for agriculture irrigation. One of the major types of marginal-quality water is the wastewater from urban and peri-urban areas (Pedrero et al., 2010). The municipal wastewater is a potential water resource with stability of water quantity and reliable supply. Irrigation with reclaimed municipal wastewater that is properly treated and satisfied with the agricultural recycling standards has huge benefits and profound social effects (Shi et al., 2008). In recent years wastewater use has gained importance in water-scarce regions. In Pakistan 26% of national vegetable production is irrigated with wastewater (Ensink et al., 2004). In Ghana, informal irrigation involving diluted wastewater from rivers and streams occurs on an estimated 11,500 hectares, an area larger than the reported extent of formal irrigation in the country (Keraita and Drechsel, 2004). In Mexico about 260,000 hectares are irrigated with wastewater, mostly untreated (Mexico CAN, 2004). Wastewater reuse in agriculture is an ancient practice that has been generally implemented worldwide. Agricultural deployment of wastewater for irrigation is based on the value of its constituents, which are used as fertilizers. However, crop irrigation with insufficiently treated wastewater may result in health risks. The use of sewage effluent for irrigation exposes the public to the dangers of infection with a variety of pathogens such as bacteria, viruses, protozoa and helminths. Thus the benefit of wastewater reuse is limited by its potential health hazards associated with the transmission of pathogenic organisms from the irrigated soil to crops, to grazing animals and humans (Gupta et al., 2009). Human health risks from wastewater irrigation include firstly farmers’ and consumers’ exposure to pathogens including helminth infections, and secondly, organic and inorganic trace elements. Protective measures such as wearing boots and gloves, and changing irrigation methods can reduce farmer exposure (Qadir et al., 2010).