Environmental Planning

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Browsing Environmental Planning by Author "Assefa Berehanu"

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    Cleaner Production Assessment In The Ethiopian Alcohol Industries A Case Study In The Sebata Alcohol & Liquor Factory
    (Addis Ababauniversity, 2007-07) Teffera Belay; Assefa Berehanu
    Sebeta Alcohol and Liquor Factory (SALF) is a sister company of National Alcohol and Liquor Enterprise (NALE). The factory was established in 1914 in Sebeta town and uses molasses as raw material for the production of potable and technical alcohols. It consists of a distillery and filling plants. Its installed daily production capacity is 2500 liters of potable alcohol and about 5000 liters of various liquors. The current production capacity was found to be on average 2100 liters of 95.7oGL potable (fine) and 250 liters of 93oGL technical alcohols per day when the factory was running normally. Water balance, material balance and energy balance were drawn only for the distillery plant for the filling section was under maintenance during sampling. The molasses, water and energy consumption were found to be 6.3 kg, 168 liters and 22.12 MJ liters per liter of 96oGL alcohol. The average BOD, COD and TDS in the wastewater were 20,866, 53,514 and 19000 mg/l respectively. The total alcohol loss from the fermentation, decantation and distillation process units was significant with the value of 13.22 %. The stillage from mash column is found a severe source of water pollution. The fermentation efficiency (78.02%), alcohol recovery at distillation unit (83.3%) and overall alcohol conversion efficiency (65.0%) were found to be low compared to values of similar technologies in India, South Africa and Brazil. The steam generation and distribution systems were studied and the boiler combustion efficiency was found extremely low (29%) resulting from excess air supply. Similarly, other sources of heat loss were identified and carefully examined The cleaner production options were generated, selected and evaluated for the distillery plant. CO2 Recovery, Cooling water recycling, lost heat recovery in the stillage and spent lee, indirect heating, generation of methane and fertilizer from stillage were considered for improving resource utilization and reducing pollution loads. Other GHK practices were recommended to bring overall efficiency in the plant
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    Comparative Study of Macroinvertebrates and Diatoms as Bioindicators of River Water Quality in Addis Ababa
    (Addis Ababauniversity, 2008-01) Addis Taffere; Assefa Berehanu
    A crucial element in planning water quality assessment, management and conservation programme of a river is the selection of the biological indicators used to appraise biodiversity and environmental conditions. The present study, therefore, aimed at comparing macroinvertebrates and diatoms as bioindicators of river water quality in Addis Ababa. A total of 16 sampling stations were selected along the course of Kebena River and Little and Big Akaki Rivers for qualitative evaluation of physical habitats and collection of samples used for the determination of the taxonomic composition and abundance of macroinvertebrates and diatoms. Riffle sites were chosen for sampling to make the comparison among sites easier. Standard methods of sampling and analysis of samples were employed throughout the study period. Biotic indices and multivariate analytical methods, particularly dissimilarity index, clustering and indirect ordinations were used for the analysis of the results. Macroinvertebrates diversity was extremely poor precluding comparison among sampling stations. The highest and lowest macroinvertebrates taxa richness was 5 and 0 respectively. Surprisingly, only two macroinvertebrates taxa were found at the upstream site of Kebena River, which had the least anthropogenic disturbance but with the least physical habitat quality (40.6 %). But, the highest diatom tax richness (30 taxa) was observed at this site followed by 17 taxa at the upstream of both Little Akaki and Big Akaki Rivers. The lowest diatom taxa richness (4 taxa) was observed near the discharge point of Awash Tannery, where other industries are also concentrated. Community loss index for diatom data was higher at sampling sites receiving industrial effluent. All diatom biotic indices were indicative of responses to load of pollution though it was not possible to select the index that could discriminate impacted sites from reference site clearly with such cross-sectional study. Generally, the study depicted that the rivers in Addis Ababa are highly affected by physical habitat degradation and pollution due to point and non-point sources. Based on biotic indices and multivariate analysis results, diatoms are found to be better than macroinvertebrates in indicating sources and degree of pollution as well as in discriminating reference site from impacted sites of the study area. Hence, studies that consider seasonal variations and all the factors that determine diatoms composition are recommended in order to develop a refined diatom-based river water quality monitoring tool for the rivers in Addis Ababa and other parts of the country. Furthermore, responsible authorities should take urgent ameliorative measures to improve water quality of the rivers in the city. Key words: macroinvertebrates; diatoms; bioindicator; water quality; monitoring; indices