Physicochemical Characterization of Upper Awash River of Ethiopia Polluted by Anmol Product Paper Factory

Pulp and paper factory effluents entering in to water bodies have been considered as major sources of pollutants in the environment. The extent of pollution depending on the nature of raw materials and the technology used in all stages of paper making process. In this study, the physicochemical characteristics of effluents from Anmol Product Ethiopia Factory (APEPF) and the receiving upper Awash River water were investigated. Composite samples, with a total sample volume of 2 L from each site was collected for 12 hours and in the month of January to March, 2015 of the Ethiopian dry season using polyethylene sample bottles. Sample preservation, storage, pretreatments and psychochemical characterization were performed according to standard procedures recommended by American Public Health Association (APHA, 2005). Mean comparison were made to examine spatial variations of physicochemical characteristics along the river water as a result of discharged effluents from the factory. Moreover, the results were compared with the National (EEPA, 2010) and WHO (2008) standards. The results showed that the raw effluent comprised of 298-501 mg/L of Total Suspended Solids (TSS), 1032-2333 mg/L of Total Dissolved Solids (TDS), and pH varied from 3.2-10.7. The five day Biological Oxygen Demand (BOD5) and Chemical Oxygen Demand (COD) of the raw effluent ranged from 470-2499 mg/L and 2969-5847 mg/L, respectively. Aerobic treatment of raw effluent were not significantly reduced TSS (112-532 mg/L), BOD5 (405-1315 mg/L), and COD (2304-3729 mg/L). Moreover, TDS, Electrical Conductivity (EC), Total Nitrogen (TN), Total Phosphorus (TP), Potassium (K), Chlorides (Cl-), and Sulphates (SO42-) were found superior after treatment. The values of most of these parameters were found higher than the Ethiopian Environmental Protection Authority (EEPA) and World Health Organization (WHO) limit prescribed for industrial effluent discharge. The ANOVA result indicated the levels of measured parameters were highest at the point of entry followed by downstream samples, and the least value was recorded at the upstream samples. Moreover, the recorded values were much higher than the maximum allowable limit even at downstream of the river. The dendrogram of hierarchical clustering clearly indicated that effluents from APEPF contributed to the change in composition of river water samples taken from downstream of the river. All these confirmed APEPF effluent discharged to the river was not in accordance with both national and WHO standards and found to have considerable effect on the upper Awash River water quality.