Removal of Chromium and Some Selected Nutrients from Tannery Waste Water by Adsorption Methods of Sugar Bagasse Activated Carbon: Case Study on Addis Ababa Tannery Share Company

摘要

Leather tanning has been ranked as one of the most polluting activities in Ethiopia because most of them do not treat or partially treat wastewater and release to the environment which pose many environmental and health problems. As a result cost effective and efficient method of wastewater treatment was undertaken by the use of sugar bagasse activated carbon. In this paper, study was performed at Addis Ababa tannery share Company to remove their wastewater constituents of chromium, ammonium, nitrate and sulfide which has concentrations of 2300.4 mg/l, 163 mg/l, and 250 mg /l and 120 mg/l, respectively in which all are above the permissible limit. The prepared activated carbon has particle size of 300μm, moisture content of 8.1%, bulk density of 0.423 g/cm3 and porosity of 67.21%. The effects of pH and adsorbent dose were also studied on the removal of these pollutants and the result shows that the adsorptions of ammonium nitrate and sulfide were 80.56%, 71.86% and 81.79%, respectively for 2 g of adsorbent and for chromium it was 100% for 1.5 g adsorbent. On the other hand, the adsorptions of ammonia, nitrate and sulfide were 87.63%, 77.95% and 100%, respectively at pH 5. For chromium it was 100% at pH 7. The activated carbon has different adsorption capacity for different nutrient and metal ion studied in which chromium100% sulfide 81.79% ammonia 80.56% nitrate 71.86%. At pH 5 removal of nutrients were in the order of sulfide 100% ammonia 87.63% nitrate 77.95%.