Assessment of Heavy Metals Pollution and Analysis of Physicochemical Parameters of Effluent Discharged From Dashen Beer Factory North Shoa Zone, Amhara, Regional State, Ethiopia

Abstract

The purpose of this study was to assess heavy metals pollution (Pb, Zn, Fe, Cu, Ni, Cr, Cd, Co and Mn) and analysis of physicochemical parameters (temperature, pH, TSS, TDS, EC, phosphate, BOD and COD) in discharged effluent from Dashen Beer wastewater in North Shoa, Amhara Regional State. Wastewater samples were collected from three zones (effluent inlet, equalization tank and final discharge). After pretreatment, the digestion temperature (250 0C), volume of reagents used (4 ml HNO3 and 1 ml HCl), digestion times (3 hrs) was optimized and the levels of selected metals were determined by inductively coupled plasma optical emission spectroscopy (ICP-OES). The validation of this procedure was performed by spiking the samples with studied solution of each metal having known concentrations and percentage recovery values in the range 92.367-122.55% were obtained. The results obtained from this study showed overall concentrations of heavy metals (Pb, Zn, Fe, Cu, Ni, Cr, Cd, Co and Mn) in the range 0.411-1.405, 0.371-0.405, 1.34-2.738, 0.076-0.125, 0.049- 0.061, 0.128-0.133, BDL, 0.05-0.056 and 0.089-0.105 mg/L respectively. The concentrations of those heavy metals (Zn, Fe, Cu, Ni, Cd, Co and Mn) in the wastewater below the recommended limit of WHO and the concentrations of Pb and Cr above it and need special treatment plant to reduce their pollution effect. The range values of physicochemical parameters (temperature, pH, EC, TDS and phosphate) in the wastewater 23.0-26.0 ℃, 6.64- 9.75, 2.73-6.684 μs/cm,1.41-3.54 mg/L and 0.43-1.73 mg/L were recorded respectively and values were in the wastewater below the recommended set limit by WHO. The experimental values of TSS, BOD and COD, 94.67-309.33, 173.33-346.33 and 368-423.42 mg/L were obtained respectively and above the recommended set limit by WHO.