ICAMS 2016 – 6 th International Conference on Advanced Materials and Systems CHROMIUM REMOVAL FROM THE TANNERY WASTEWATER USING INDIGENOUS ADSORBENT MD. ABUL HASHEM, MD. SHAHRUK NUR-A-TOMAL, AZIZA AHSAN Khulna University of Engineering & Technology (KUET), Leather Engineering Department, Khulna-9203, Bangladesh, mahashem96@yahoo.com, mahashem@mail.kuet.ac.bd Tannery is recognized as high-strength waste-generating industry. In tannery, leather processing involves a series of chemical treatments and mechanical operations to attain the prescribed characteristics. Inapt disposal of solid and liquid waste from the tannery cause a serious environmental pollution. Chromium containing wastewater is generated from chrome tanning operation which is the most hazardous pollutants released to the environment. Treatment of high- chromium-containing wastewater is a major concern in leather processing. In this study, indigenous adsorbent was investigated to remove the metals, especially chromium from the chrome tanning wastewater. The prepared adsorbent was directly mixed with chrome tanning wastewater. Various parameters such as adsorbent dose and contact time were optimized in batch- wise technique. The maximum removal of chromium was attained 99.9%. The use of indigenous adsorbent for the removal of chromium could be better instead of conventional methods. Keywords: tannery, chrome tanning wastewater, indigenous adsorbent. INTRODUCTION Tannery strengthens the economy significantly, though it is facing severe challenges due to its environmental pollution caused by the wastes produced during leather manufacturing. In tannery, leather processing involves a series of chemical treatments and mechanical operations to attain the recommended characteristics. Inapt disposal of wastewater and solid waste from the tannery cause a serious environmental pollution. During leather processing, huge volume of wastewater is generated. Since soaking to finishing operations, each and every chemical operation generate considerable amount of wastewater. Chromium containing wastewater is generated from chrome tanning operation which is the most hazardous pollutants released to the environment from the tannery. Tanning is the subsequent operation of pickling and is the most common technique in leather processing. In tanning, 90% tanneries use basic chromium sulfate as tanning agent to obtain better quality leather (Avindhan et al., 2004). The basic chromium sulfate binds with collagen to make it stabilize against biodegradation (Hashem et al., 2015). Averagely, only 60% of the chromium is up taken by the pickled pelt and 40% chromium remains in the solid/liquid wastes, especially as spent chrome liquor (Fabiani et al., 1997). In conventional chrome tanning, wastewater contains 1500-3000 mg/L chromium (Suresh et al., 2001). Discharging of high chromium containing tanning wastewater is a major concern in leather processing. It is also a potential pollutant to soil, water, and air under definite conditions. A fraction of discharged spent chrome liquor is directly mixed with the water body, which causes serious environmental pollution; another fraction of chromium is settled in the lagoon or adsorbed by sediment/soil. Chromium has toxicity to humans at high doses. It exists in several oxidation states, with trivalent chromium and hexavalent chromium species being the most common forms (Kotas and Stasicka, 2000). The occupational exposure of chromium has been widespread and it is shown that chromium (III) under certain ligand conditions in environments leads to cell death