EVALUATION OF ENVIRONMENTAL IMPACT OF TIGRIS RIVER POLLUTION (BETWEEN JADIRRIYA AND DORA BRIDGES)

Abstract

Al-Saidiya PN pumping station raw sewage discharges forms the major pollution source to Tigris river between Al-Jadirriya and Al-Dora bridges, its main importance comes from its location upstream to Al-Dora water treatment plant. In an attempt to evaluate the environmental effects on water quality within the river reach under study, special emphasis was put on evaluating the environmental impact of Al-Saidiya (PN) pumping station wastewater discharges on downstream intakes of water supply, using parameters Oil & Grease, DO, BOD and Coliform & Feacal coliform, in addition to SO4, Cl & EC distributions
in three dimensions. It was found that most pollutants concentrations at Al-Dora WTP range within the
permissible level for Iraqi raw waters; with the exceptions of Coliform and Feacal Coliform that are highly above the limits; SO4 and BOD showed some high values. Concentrations of pollutants NH3, SO4, BOD, Coliform and Feacal Coliform showed higher values at Al-Dora WTP site compared to Al-Qadissiya and Al-Rasheed WTPs sites. Oil & Grease high concentrations measured at Al-Saidiya pumping station showed that it should not be allowed to discharge directly to the river. Another importance of this location comes from the river hydraulic characteristics represented by the sharp U-shape bend that enhances the transversal mixing process, and hence facilitates the pollutants distribution, through the secondary currents and spiral flow.