Water Pollution/Quality Assessment in Relation to Wet Coffee Processing Plants in Surface and Shallow Groundwater in Sidama and Gedeo Zones (SNNPR)

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Addis Ababa University


The study area located in Southern Nation and Nationality People Region (SNNPR) and encompass Sidama & Gedeo Zones that are among all the coffee growing region of Ethiopia, bounded between 37° 54'N to 39°8 N latitude and 5° 52'E to 7° 13'E longitude in which most part of it situated in the rift valley lakes basin and the remaining part in Genale Dawa basin . The study area has different land form characteristics varied from High Mountain up to low lands: its altitude varies from the highest peak (3000m) up to lowlands (1100 m) High water usage, channeling residual water and the pulp together, in efficiency of the traditional waste disposal pits, absence of monitoring and lack of sustainable wet coffee production strategy and policy are some of the factors that aggravate the impact of the processing plants on the poll ution of water bodies were di scussed in problem identification and analysis. Measured values of physical parameters such as turbidity and pH are out of the range of WHO guideline values and standards. From the Physical observation itself during coffee processing periods rivers and streams have objectionable color odor and taste so that the waters have evil or pungent small and test. TDS and EC values of rivers and streams in particular spring and boreholes in general shows that the water is fresh. Based on the measured value of the total hardness in terms of CaC03 the surface and groundwaters of the study area classified as moderately hard. The limited water chemical analysis fi'om previous representative sources indicated that the river and ground waters are Na HC03 type of water, the dominant cation being Na and anion bicarbonate. The highest value BOD and COD in river water is 8750 and 3120mg/1 that have a potential for decreasing greatly the level of dissolved oxygen in the rivers that reduces the diversity of aquatic life. The maximum COD value of the effiuent obtained from this analysis (24,600mg/l) is 98 times higher than the EPA standard fro effiuent discharges to inland waters. The highest BOD value was 39 times higher than the EPA standard. The bad, evil and pungent smell that can be sensed along the river courses during coffee processing periods were explained by the concentration of Ammonia (NH3) that was ranged from 1.48to 90mg/1 and was much higher than the recommended limits. The highest nitrite (N02-) concentration was 60mg/1 in Melkadimtu Rivers. From the total analyzed samples about 50% of them had their values were nearly I mg/I, which are far higher than levels in unpolluted waters (0.03mg/I). Rural communities that use river water as their source of water supply may expose to carcinogenic effect due to this level of nitrite. Coffee pulp, which is one of the bypro ducts of coffee processing, have some economical applications that may become evident as their use is increased. Compost and fertilization, Pulp beverage, animal feed, fuel wood substitutes are some of the suggested measures to be taken to mitigate the effects.



Water Pollution Quality Assessment