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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/2698

Authors: Eyasu, Mekete
Advisors: Dr. Araya Asfaw
Dr. Nigist Asfaw
Keywords: Moringa stenopetala seed cake powder
Biogas, coagulation
Brewery wastewater
averageremoval efficiency
Copyright: Nov-2008
Date Added: 6-May-2012
Publisher: AAU
Abstract: Energy is a key factor to socio-economic development. There is clear correlation between energy consumption and the level of standard of living. On the other hand, human societies produce wastes that can represent a useful raw material for the production of energy, and recovery of by-products and component water. In this paper, the potential of Moringa stenopetala seed cake powder which is a byproduct of the hexane extract of the seed is evaluated for its contribution in biogas production and brewery wastewater treatment through coagulation. Moringa stenopetala seed cake powder was used as feedstock in nine serum bottles with a capacity of 2.5 L. The anaerobic digestion was conducted in triplicate with 10%, 15% and 20% of their working volume inoculated with actively digested biogas slurry. The experimental findings showed that the composition of methane in all of the digesters is within the range of 62-72%. The amount of biogas produced over a retention time of 68 days was also between 6.6 L to 7.7 L. The Physico-chemical characteristics of the seed cake powder revealed the suitability of the substrate for biogas production. No inhibitory factors were found within the seed cake powder. However, the total solids percentage of the seed cake powder was about 93% which can be considered as a drawback in areas which suffer from water drought for large scale application of the substrate in biogas production. The other application of the seed cake powder studied in this work is to evaluate its potential for brewery wastewater treatment. The brewing industry is one of the largest industrial users of water. The wastewater is also characterized by different valuable nutrients. Recovery of these resources and treatment of the wastewater to reduce the impact on the receiving water bodies is an important aspect of this research. Moringa stenopetala seed cake powder was found to be an effective coagulant in reducing total phosphorus, turbidity and total suspended solids from the brewery effluent achieving an average removal efficiency of more than 90%. A relatively better efficiency of more than 80% was achieved for COD and BOD. The removal efficiency for total nitrogen was about 43%, a lower but important figure as coagulation is a physical process. However, conductivity, total dissolved solids and pH were not significantly affected through the coagulation process. Better removal efficiency was obtained at a coagulant concentration of 500mg/L. Therefore, Moringa stenopetala seed cake powder which is a by-product of the hexane extract of the seed can be managed by using as substrate for biogas production and as coagulant for brewery wastewater treatment.
URI: http://hdl.handle.net/123456789/2698
Appears in:Thesis - Environmental Sciences

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