Abstract:
Afrotan tannery was established in 1983 in Albageer Industrial Area- Algazeera State - Sudan. It tans about 20000 skins per day and generates high amount of waste water. Beside the tannery, there are three units of waste water treatment. These treatment units precipitate high amounts of sludge in sedimentation tanks of these units. The tannery collects all this sludge, treats by adding Aluminum sulphate, lime and Poly electrolyte respectively, dewaters by pressing by centrifuge machine and fills it in land. The aim of this study is to determine and to investigate the parameters in sludge before treatment (slurry sludge) and after treatment (dewatered sludge). The analysis was carried out by using standards methods for the Examination of Water and Waste Water, Edition 20, (1998). The results showed that the values of BOD, COD, TVS, NH3, NH4, NO3, SO3, SO4, Cl, Fe, Ca, Na, K, Al and Cr in slurry sludge (before treatment) were found to be 33600 mg/l, 56000 mg/l, 96.0%, 196 mg/kg, 238 mg/kg, nil, 0.25 %, 0.624%, 6747.8 mg/l, 16.18 mg/l, 18.421 mg/l, 8.864 mg/l, 10.609 mg/l, 0.00215 mg/l and 13.23 mg/l, respectively. The values of these parameters in treated and dewatered sludge (after treatment) were found to 40000 mg/l, 68000 mg/l, 81.7%, 252 mg/kg, 306 mg/kg, 28 mg/kg, 1.2 %, 1.44 %, 5100.8 mg/l, 4.911 mg/l, 21.328 mg/l, 9.041 mg/l, 8.146 mg/l, 0.00189 mg/l and 5.897 mg/l, respectively. The study recommended that it is important to prevent filling this sludge in the land to avoid soil contamination and also to conduct further studies to use this sludge in agriculture or others purposes.
