Impact of Wet Coffee Processing Plant Effluent on Water Quality and Macro- Invertebrate of Ketalla and Ajacho Rivers in Kecha-Birra Woreda, SNNPR, Ethiopia

Abstract

Freshwater resources are increasingly subject to pollution because of escalating human population growth, accompanied by urbanization, industrialization, and the increased demand for food. Consequently, freshwater quality and aquatic ecosystem structure and function have been severely impaired. The use of benthic macro-invertebrates together with physicochemical parameters was considered as the reliable method of water quality monitoring. The present study was conducted at Kecha-Birra district, SNNPR to assess the impact of wet coffee processing plant effluent on benthic macro-invertebrates and water quality of rivers that receiving coffee wastewater. In this study, environmental impact assessment was conducted by comparing UPS (reference) site with DS locations during peak coffee processing period. Physicochemical, biological and QHEI surveys were applied in data collection. Cross-Sectional study design was used in this research. Three composite replicates were taken in each refinery and on 7 sampling sites. In current study, physicochemical parameters of coffee wastewater on average consist of a low amount of (DO=5.7), (pH=6.7) and DO (>1) at the site of row influent sampling sites. The study revealed slightly increased level of organic pollution at location at ENP and below coffee effluent discharge points. One way analysis of variance (ANOVA) showed insignificant variation (P<0.05) for all measured physicochemical parameters except BOD5 and COD. In present study, results of some of physicochemical parameters were out of Ethiopian and WHO environmental protection agency water quality standards. Furthermore, for biological analysis 450 macro-invertebrate individuals were identified belonging 30 different taxa. In this study, (%EPT), EPT and Chironomidae ratio, Simpson, Shannon, Evenness, FBI and Odonata matrices were used to understand water quality. Except, FBI and %Odonata all selected index was lower at DS site. Besides, QHEI score result displays that except the Ajacho DS site all values were at the range of good water quality condition (55 % to 69%). Generally, the study depicted that the Study Rivers was not affected by physical habitat degradation but, somewhat affected by wet coffee processing effluent. The government (stockholders) not only put rules and regulations for wet coffee processing plant owners and crews. However, prior to punishment they should create awareness and support how to design & construct modern wastewater stabilization ponds or other waste water trearment technologies