Andualem, Mekonnen Hiruy (2000) Developing a Laboratory Scale Sequencing Batch Reactor and Evaluating its Performance for the Treatment of Tannery Wastewater. Masters thesis, Addis Ababa University.
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Abstract
Tannery wastewaters contain high levels of organic matter, nitrogenous compounds, sulfides and other pollutants. These pollutants can cause undesirable effect on the ecosystem and public health. In Ethiopia most of leather industries discharge their effluent with out any treatment to the near by rivers. This creates a serious effect on aquatic biota and surrounding environment. To minimize the effects, these pollutants must be eliminated/reduced to the acceptable limits during wastewater treatment. Biological treatment methods are both cost effective and environmentally sound alternative for the treatments of tannery wastewater than physic-chemical methods. The objective of this study was to develop laboratory-scale sequencing batch reactor and evaluate the biological removal efficiencies of various pollutants from tannery wastewater. To achieve this objective, the removal efficiencies of COD and TN were investigated under different cycle times in steady-state condition. The removal efficiencies of the sequencing batch reactor for carbon, nitrogen, sulfur and phosphorus were also evaluated for a cycle time of 8 hours. In addition, the effects of fill time on the overall COD removal efficiencies were studied. The overall COD removal efficiencies were 71 ± 3.6% at a cycle time of 6-h, 85 ± 1.5% at a cycle time of 8-h, 89 ± 1.5 % at a cycle time of 12-h and 92 ± 2.6 % at a cycle time of 24-h. The TN removal efficiencies were 33% at a cycle time of 6-h, 39% at a cycle time of 8-h, 44% at a cycle time of 12-h and 49% at a cycle time of 24-h. The overall COD removal efficiencies were 94% for 180-minute fill time, 90% for 83-minute fill time and 85% for 48 and 39 minutes fill time. The removal efficiencies at 8 hour cycle were 85% for carbon, 38% for total nitrogen, 35% for ammonia-nitrogen (NH4+-N), and 99.9 % for sulfide, 100% and 54.3% orthophosphate and total phosphate, respectively. In the steady-state condition, the removal efficiencies of COD and TN increased as the cycle time (HRT) increased. The removal efficiency of COD increased as the length of feed time increased. Thus, the Sequencing batch reactor was found to be efficient for the removal of organic matter, sulfide and phosphorous from tanner wastewater.
| Item Type: | Thesis (Masters) |
|---|---|
| Uncontrolled Keywords: | Biological organic matter and sulfide removal, ammonification, nitrification, denitrification, sequencing batch reactors, tannery effluents |
| Subjects: | G Geography. Anthropology. Recreation > GE Environmental Sciences T Technology > T Technology (General) |
| Divisions: | Africana |
| Depositing User: | Selom Ghislain |
| Date Deposited: | 16 Aug 2018 09:20 |
| Last Modified: | 16 Aug 2018 09:20 |
| URI: | http://thesisbank.jhia.ac.ke/id/eprint/4774 |
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