Wastewater Irrigation: The State of Play

Abstract

As competition among industrial, agricultural, urban and environmental sectors for freshwater intensifies, wastewater is frequently being seen as a valuable resource rather than mere waste. Furthermore, wise reuse of this water alleviates environmental concerns attendant with its discharge to coastal environments and inland waterways. Globally, around 20 million ha of land are irrigated with wastewater, either neat or partially diluted. This figure is likely to increase markedly over the next few decades in response to rising levels of water stress in inhabited catchments -in 1995 around 2.3 billion people lived in river basins considered to be water stressed and this number is expected to increase to 3.5 billion by 2025. Here we review the current status of wastewater irrigation by providing an overview of the extent of the practice in different parts of the world and through an assessment of the current understanding of various issues relating to sustainable and safe management of irrigation with wastewater. A theme that emerges is that wastewater irrigation is not only more common in water stressed regions such as the Near East, but the rationale for the practice also tends to differ between the developing and developed worlds. In developing nations the prime drivers for wastewater irrigation appears to be livelihood dependence and food security, whereas environmental agenda appear to hold greater sway in the developed world. The following were identified as key areas requiring greater understanding for the long-term sustainability of wastewater irrigation: (i) accumulation of bio-available forms of heavy metals in soils, (ii) an understanding of the balance of various factors affecting the environmental fate of organics in wastewater irrigated soils (iii) the influence of reuse schemes on catchment hydrology, including transport of salt loads, (iv) risk models for helminth infections (pertinent to developing nations), (v) microbiological contamination risks for aquifers and surface waters, (vi) transfer efficiencies of chemical contaminants from soil to plant, (vii) effects of chronic exposure of people to chemical contaminants in wastewater, and (iix) strategies for engaging the public in wastewater irrigation schemes.

Treated wastewater irrigation effects on soil hydraulic conductivity and aggregate stability of loamy soils in Israel

“…Israel is a world leader in TWW reuse for agricultural irrigation (Hamilton et al, 2007). According to the Israeli Water Authority (2014), 35.4% of Israel's total FW consumption (1212.7 hm 3 ) in 2012 was used for agricultural purposes and 57.2% for domestic purposes.…”

Biodegradation of three selected benzotriazoles in aquifer materials under aerobic and anaerobic conditions

“…Wastewater from municipal wastewater treatment plants has been increasingly reclaimed and reused in many parts of the world due to the water shortage (Hamilton et al, 2007). Managed aquifer recharge (MAR), also called as "artificial aquifer recharge", is a technology that can be used to facilitate the reclamation and reuse of treated wastewater from wastewater treatment plants (Dillon, 2005).…”

Alterações Eletroquímicas E Dinâmica De Nutrientes Na Solução Do Solo Em Arroz Irrigado Com Lixiviado Industrial Tratado

“…Conforme Hamilton et al (2007), efluentes tratados industriais e domésticos possuem valores médios de RAS na faixa de 4,5 a 8, e valores de RAS acima de 3 podem interferir negativamente as características do solo, especialmente quando a condutividade elétrica dele for menor do que 1 mS cm -1 e o pH for superior à neutralidade.…”

“…Alternativas para a disposição de águas residuárias são necessárias para a redução dos desequilíbrios em corpos d'água (Hamilton et al, 2007). O uso agrícola dos efluentes industriais tratados tem grande potencial (Feigin et al, 1991), pois os nutrientes presentes nessas águas podem favorecer o desenvolvimento de plantas como o arroz.…”