Browsing by Author "Gutama, Moroda"

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    Water and Wastewater Minimization in Tannery by Using Water Pinch Technology Case Study (Ethio Leather Industry (ELICO) Glove and Hide Unit(Ethio Leather Industry (ELICO) Glove and Hide Unit
    (Addis Ababa University, 2011-07) Gutama, Moroda; Nurelegn, Tefera (PhD)
    In tanneries, the phases of conditioning and preparing the hide/skin for tanning, as well as the transportation and fixation of tanning substances are all carried out in aqueous media. Most of the steps of these processes are carried out with fresh water. This leads to the generation of high wastewater flowrates which will have to be treated due to the relatively high concentrations of pollutants. The high effluent volume requires huge investments for effluent treatment plants in order to meet the required specification for the discharge of liquid effluents to various water bodies. In this study the total water consumption reduction of the case study tannery is investigated by using water reuse technique in some stages of the process. For the systematic design of water reuse networks, the theory of the water pinch methodology is described, which are proved to be effective in identifying water reuse opportunities. Experimental results on pilot scale are shown that the methodology is demonstrated to be successful. Water reuse reduces the load of the wastewater treatment plant as well as it reduces the costs. During the analysis, it was tested that 100% of the effluent from de-liming discharge can be reused for presoaking and main soaking stages, reuse in bating washing-1 100% and bating washing-2 75% from bating washing-3, and the reuse of 80% of washing after shaving for tanning float. The physical and chemical parameters analyzed in the processes and for the products with reuse practice did not present any considerable difference when compared with the conventional process. This demonstrates the viability of reuse practice in tanning industry. This study identified a potential scope of reducing both freshwater and wastewater by 44%. In turn the water reduction represents a total potential annual savings of 307200 Birr, taking into account the raw water and wastewater treatment costs, labor cost, electrical and chemical costs.