Wastewater treatment practices by tanneries: Case of Skyfat Tannery and Leather Industries of Uganda Tanneries, Jinja, Uganda
MetadataShow full item record
The Leather industry in Uganda is of economic importance in terms of providing employment opportunities and revenue. However, leather manufacturing is a water intensive process and generates a significant volume of wastewater mainly characterized by high salinity, high organic loading and pollutants. Therefore, the main objective of this study was to assess the existing wastewater management practices in the leather industry of Uganda focusing on two tanneries (Skyfat tannery (SFT) and Leather Industries of Uganda tannery (LIU) so as to determine their efficiency and effectiveness in addressing potential pollution incidents. The study employed both qualitative and quantitative research methods of data collection. Selected physico-chemical parameters namely; BOD, COD, Electrical Conductivity (EC), pH, Sulphides, TSS, Chromium (Cr) and Sulphates characteristics of the wastewater were determined. Review of relevant literature was performed and one-to-one semi-structured interviews were held with key informants in the two tanneries and the District and Municipal Environment Officers of Jinja district. Wastewater treatment efficiency was determined and the pollution load estimated for both tanneries. Analysis results of all selected parameters from Skyfat tannery at the final effluent discharge point into the environment revealed high concentrations above the National Environment Standards for Discharge of Effluent into Water or on Land for BOD, Sulphides COD, TSS, pH and Total Chromium, whereas, analysis results for all the selected parameters (BOD, Sulphides COD, TSS, pH, EC, Sulphates and Total Chromium) from Leather Industries of Uganda tannery at the final effluent discharge point into the National sewer line revealed that all the parameters complied with the National Water and Sewerage Corporation (NWSC) standards for discharge of effluent into public sewers. Determination of efficiency of treatment plants in the two tanneries indicated high removal for chromium above 99%, followed by<70% for the rest of the parameters. The removal efficiency of chromium at Skyfat tannery was above 99%, even though the final concentration in the effluent was beyond the acceptable discharge standards. SFT releases a total pollution load of 833.28 kg/day for all the selected parameters and LIU releases a total pollution load of 235.28 kg/day. SFT discharges an average of 1243.30 m3/day of effluent and LIU discharges 177.28 m3/day of effluent. Both tanneries use the activated sludge process (ASP) for the treatment of their effluents. However the ASP process in both tanneries was incomplete because they did not have clarifiers to ensure effective removal of sludge and the aeration system for SFT was inadequate compared to the volume of effluent generated hence could not enable complete oxidation of sulphides. The effluent discharged by SFT (semi-finished leather processing tannery) was not complying with the national discharge standards. The effluent treatment plant had lower pollutant removal efficiency and the tannery discharged a higher pollution load as compared to LIU (finished leather processing tannery). Therefore, it is recommended that SFT should improve on both primary and secondary treatment of its effluent through expansion of the sedimentation ponds to allow ample effluent retention time, install a diffused aeration system to attain complete oxidation of sulphides and as well install a chromium recovery plant to avoid generation of chrome sludge that poses disposal challenges. Both tanneries are recommended to install clarifiers so as to attain complete removal of organic matter from the effluent, expand the aeration ponds and implement cleaner production measures in order to reduce consumption of chemical tanning inputs and production of excessive wastewater .