Wet coffee processing wastewater charachterization and treatment using effective microorganism activated solution

Abstract

Wet coffee processing, if not conducted properly, can harm the environment. Hence, a study conducted in Ethiopia, Jimma Zone, Gomma and Mana wereda at Geruke, Gembe, Omobeko and Bulbulo sites from four points (upper stream of the river, pulping, fermentation tank, downstream). In order to characterize the wet coffee processing wastewater on physicochemical qualities and the laboratory treatment of pulping wastewater using effective microorganism activated solution at Jimma University environmental health laboratory. Physicochemical characterization of water samples taken from four points of all locations was done with three replication. The laboratory analysis was in factorial arrangement of CRD designed with two factors and three replications. The factors were pulping wastewater from four locations (Omobeko, Bulbulo, Gembe and Geruke) and the effective microorganism with two types activation and five levels. EMAS1 with 0ml, 2ml, 4ml, 6ml, and 8ml and EMAS2 with 0ml, 3ml, 6ml, 9ml and 12ml. As a result, the wastewater showed very high BOD (12150 mg/l), TSS (1805.8mg/l), TDS (1702), turbidity (647.5 NTU), EC (568.5 µS/cm), NO3 (24.87 mg/l), NH3 (11.06 mg/l), PO4 (4.85 mg/l) and low pH (2.95) and DO (0.02 mg/l) values. The EMAS1 treated pulping wastewater show a reduction of 49.5 - 60.5% BOD, 23.05 - 26.88% NO3, 41-46% NH3 36 - 52% PO4, 24 - 33% EC, 35 - 47% turbidity, 37.5 - 52.5% TSS and 41.7 - 49.1% TDS and increment of pH by 1.27 - 1.69 and DO by 1.4 - 2.5mg/l amount for effluent treated with 4ml EMAS1. Whereas EMAS2 pulping wastewater was show reduction of 40 - 45% NO3, 72 - 82% NH3, 30 - 52% PO4 when treated with 9ml EMAS2 and 49.5 - 60.5% BOD5, 29 - 40% EC, 40 - 53% turbidity ,39.9% - 52.5% TSS and 47.8% - 56.6% TDS and increment of pH 1.1 - 1.59 and DO by 1.99 - 2.8 mg/l amount when treated with 6ml EMAS2. The quality of wastewater improved by using EMAS; the relatively good improvement of wastewater was on the use of EMAS2 6ml due to its economical benefit and better wastewater quality improvement than EMAS1 of 4ml. So using 6ml EMAS2 advantageous to use for the treatment of wet coffee processing wastewater as far as this study was concerned. The wastewaters from four locations were highly polluted with the high pollution load on pulping and fermentation wastewater. Hence, there should be strict environmental regulation imposed on coffee processing stations not only during establishment but also during subsequent operations. However, further multidisciplinary researches are imperative on the impact of wet coffee processing wastewater and its treatment. It is advisable to do confirmation of this research both on in-situ and ex-situ condition.