Journal of Environmental Protection, 2010, 1, 216-225 doi:10.4236/jep.2010.13026 Published Online September 2010 (http://www.SciRP.org/journal/jep) Copyright © 2010 SciRes. JEP Evaluation of Treated Municipal Wastewater Quality for Irrigation Abdul Hameed M. Jawad Alobaidy, Mukheled A. Al-Sameraiy, Abass J. Kadhem, Athmar Abdul Majeed Environmental Research Center, University of Technology, Baghdad, Iraq. Email: jawaddhy@yahoo.co.in, mukheled@yahoo.com, aik_mik@yahoo.com, athmarjaffer@yahoo.com Received May 27 th , 2010; revised June 24 th , 2010; accepted June 27 th , 2010. ABSTRACT Wastewater reuse is a useful tool in minimizing the amount of wastewater in the environment. Therefore, evaluation of the suitability of Al-Rustamiyah WWTP municipal treated wastewater for irrigation was made according to its compo- sition and the international irrigation water quality standards. In addition, to classify water quality and to evaluate its suitability for irrigation purposes, Sodium Adsorption Ratio (SAR), Soluble Sodium Percentage (SSP) and Residual Sodium Carbonate (RSC) were calculated following standard equations and found experimentally as (2.11), (35.67) and (–12.75) respectively. Plotting the values of conductivity (EC) and sodium absorption ratio (SAR) on the US salin- ity diagram illustrated that most of the samples fall in the field of C3-S1, indicating high salinity and low sodium water which can be used for irrigation on almost all types of soil without danger of exchangeable sodium. Furthermore, the data indicate slight to moderate degree of restriction on the use of this treated wastewater in irrigation due to chloride hazard. RSC value is negative at all sampling sites, indicating that there is no complete precipitation of calcium and magnesium. Overall, the treated wastewater can be classified with few exceptions as suitable for irrigation use. Keywords: Wastewater Reuse, Irrigation, Sodium Adsorption Ratio (SAR), Residual Sodium Carbonate (RSC), Soluble Sodium Percentage (SSP) 1. Introduction In many arid and semi-arid countries water is becoming an increasingly scarce resource and planners are forced to consider any sources of water which might be used economically and effectively to promote further devel- opment. Thus, the availability of good-quality water for irrigation is threatened in many places [1] and irrigated agriculture faces the challenge of using less water, in many cases of poorer quality, to irrigate lands that pro- vide food for an expanding population. The irrigation water needs can be met by using the available water more efficiently, but in many cases it will prove necessary to make increased use of municipal wastewaters [2]. The use of wastewater in agriculture has potential for both positive and negative environmental impacts [3]; with careful planning and management the use of wastewater in agriculture can be beneficial to the environment. However, the direct and indirect use of untreated wastewater in irrigated agriculture is increasing as a result of increasing global water scarcity, inadequate and inappropriate wastewater treatment and disposal, increased food insecurity and escalating fertilizer costs [4-6]. Consequently, the reuse of wastewater for agricul- ture is highly encouraged [7,8] and it is a common prac- tice for many reasons, not least of which is nutrient value and environmental protection [1,9]. Irrigation with treated municipal wastewater is considered an environmentally sound wastewater disposal practice compared to its direct disposal to the surface or ground water bodies [3,8]. Wastewater is a valuable source of plant nutrients and organic matter [10]. Nevertheless, it may contain unde- sirable chemical constituents and pathogens that pose negative environmental and health impacts [11]. At the same time, a number of risk factors have been identified in wastewater reuse, some of them are short term (e.g., microbial pathogens) whereas others have longer-term impacts that increase with the continued use of recycled water (e.g., salinity effects on soil). So, many guidelines have been developed to give a quality criteria and guid- ance on how treated wastewater (effluents) should be reused for irrigation purposes [12,13].