Reuse of Treated Wastewater for Irrigation in Misurata, Libya: Pollution and Quality Assessment

Abstract

This research focuses on evaluating the potential risks associated with the use of treated wastewater (TWW) for irrigation by drawing an analogy between the outcomes, international standards, and indices. Twelve TWW samples collected monthly for a duration of one year. The comprehensive pollution index (CPI) and organic pollution index (OPI) classified these waters as slightly and slightly to moderately polluted. Among the analyzed trace elements (Fe > Mn > Zn > Co > Cu > Cd > Pb > Cr), the Cd concentration was higher than the desired limit for irrigation water. Plotting Piper’s diagram shows that most of the TWW samples are fall into the calcium bicarbonate zone. TWW samples are all within the permissible limits in terms of pH, EC, Sodium Adsorption Ratio (SAR), Total Dissolved Solids (TDS), Soluble Sodium Percentage (SSP), Magnesium Hazard (MH), and Residual Sodium Carbonate (RSC), while the integrated salinity and alkalinity effect revealed in the U.S. salinity diagram indicates that TWW samples drop at high salinity and low sodium exchange hazard (C3-S1). The use of the TWW from Misurata for irrigation ultimately calls for control, and surveillance action plans to avoid soil contamination, salination and/or sodification.