Reuse of effluent water—benefits and risks

Abstract

There is an increasing trend to require more efficient use of water resources, both in urban and rural environments. A major mechanism that can be used to achieve greater efficiencies is the reuse of water that once would have been discarded into the environment after use. The reuse of water for agricultural irrigation is often viewed as a positive means of recycling water due to the potential large volumes of water that can be used. Recycled water can have the advantage of being a constant, reliable water source and reduces the amount of water extracted from the environment. In addition, in some cases treatment requirements may be need to be less than for water used in an urban environment due to less potential human contact. There are concerns and unknowns, however, about the impact of the quality of the recycled water, both on the crop itself and on the end users of the crops. Water quality issues that can create real or perceived problems in agriculture include nutrient and sodium concentrations, heavy metals, and the presence of contaminants such as human and animal pathogens, pharmaceuticals and endocrine disruptors. Social attitudes to the use of crops that have been irrigated with recycled waters and the resulting impact on market value of crops are also a major consideration. This paper will discuss the benefits from using different types of recycled water and outline the current knowledge and opinions relating to risks such as water quality issues. KeywordsWastewater, recycling, soil, contaminants, pathogens, irrigation IntroductionIncreasing efficiencies in crop management and the continuing increases in crop yields has increased demands on water resources for irrigation purposes. Effluents are reused for irrigation purposes in many countries around the world on all of the populated continents (USEPA 1992). A number of these countries have developed guidelines that give quality criteria and advice on how effluents should reused for irrigation purposes. Examples of these guidelines are summarised in the USEPA guidelines for water reuse manual (USEPA 1992).

Identification of Recycled Water with an Empirically Derived Symbol Increases Its Probability of Use

“…In comparison with many other environmentally friendly behaviors (for example, recycling paper or purchasing dolphin-safe tuna) the commercial agricultural use of recycled water and the personal use of consumer goods or facilities irrigated with recycled water entail more substantial economic and health risks (31). In comparison to men, women have been frequently observed to be more averse to such risks (32,33); thus the present finding might reflect more general gender differences in risk aversion.…”

Wastewater reuse in irrigation: A microbiological perspective on implications in soil fertility and human and environmental health

“…In this context, the reuse of treated wastewater represents a valid option, in some cases urged by the absence of viable alternatives (Niemczynowicz, 1999;WHO, 2006a). Besides the reduction in the use and abstraction of freshwater, wastewater reuse will also contribute to reduce the discharge of effluents into freshwater ecosystems (Bixio et al, 2006;Toze, 2006). This scenario makes wastewater an increasingly valuable resource rather than a waste product.…”

“…One of the advantages of wastewater irrigation is the supplying of nutrients that may be sufficient to replace, or at least to reduce, the use of synthetic fertilizers in agriculture (Adrover et al, 2012;Fatta-Kassinos et al, 2011;Toze, 2006). The fertilizing potential of the wastewater (assuming an application rate of 5000 m 3 /ha year) can reach annual values as high as 250 kg/ha for N, 50 kg/ha for P and 150 kg/ha for K (Pescod, 1992).…”

“…antimicrobials, personal care products, lipid regulator agents, anti-inflammatory drugs, betablockers, cancer therapeutics, contraceptives and other hormones) are contaminants of emerging concern Fatta-Kassinos et al, 2011;Kinney et al, 2006;Muñoz et al, 2009;Shi et al, 2012;Thiele-Bruhn, 2003;Toze, 2006). The fate and effect of these compounds in soils will depend on several key factors, which go far behind the chemical properties of each one or of the soil characteristics.…”

Wastewater use in agriculture and potential effects on meso and macrofauna soil

“…This potential risk is due to high biochemical and chemical oxygen demand, organic and inorganic pollutants, excess of nutrients, particularly nitrogen and phosphorus, pathogenic micro-organisms and elements that confer salinity to the water and consequently the establishment of salinity frames and sodicity in the soil, affecting its living fraction (MANCUSO & SANTOS, 2003;TOZE, 2006).…”