501 PANDHARIPANDE et al : REDUCTION OF COD & Cr (III), AND DECOLOURISATION OF TANNERY WASTEWATER Journal of Scientific & Industrial Research Vol. 71, July 2012, pp. 501-503 *Author for correspondence E-mail: slpandharipande@gmail.com Reduction of COD and chromium, and decolourisation of tannery wastewater by activated carbons from agro-wastes S L Pandharipande 1 *, Y D Urunkar 2 and Ankit Singh 1 1 Department of Chemical Engineering, Laxminarayan Institute of Technology (LIT), R T M Nagpur University, Amravati Road, Nagpur 440 033, India 2 Department of Chemical Engineering, Tatyasaheb Kore Institute of Engineering and Technology, Warananagar 416 113, India Received 16 March 2012; revised 28 May 2012; accepted 29 May 2012 This study presents decolourisation of common collection tank (CCT) & chromium tank (CT) wastewater samples, reduction of COD from lime water collection tank (LWCT) & CCT wastewater samples and reduction of chromium from CT wastewater samples. Activated carbons (ACs) were synthesized from rice husk, saw dust and sugarcane baggasse. Saw dust activated carbon reduced COD of CCT wastewater by 94.8%, whereas sugarcane baggasse activated carbon reduced COD of LWCT by 77%. Thus sugarcane baggasse activated carbon is most effective among three ACs for removal of chromium, whereas all ACs developed are equally effective for decolourisation of CCT and CT wastewater samples. Keywords : Activated carbon, Chromium adsorption, COD, Decolourisation, Rice husk, Saw dust, Sugarcane baggasse, Tannery wastewater Introduction One ton of hide leads to generation of 20-80 m 3 of foul smelling wastewater, which includes chromium (100-400 mg/l), sulphide (200-800 mg/l) and other solid waste materials. Among various studies on synthesis of activated carbon (AC) from agricultural wastes for removal of dyes from the solution and treatment of wastewater, related studies include chemically modiûed sugarcane baggasse as a potentially low-cost biosorbent for dye removal 1 , decolourisation of molasses wastewater using AC prepared from cane baggasse 2 , ACs from coconut shell impregnated with phosphoric acid 3 , colour removal from textile effluents using hardwood sawdust as an absorbent 4 , adsorption of dyes on AC synthesized from agricultural residue 5-7 , adsorption of Cr(VI) on activated rice husk carbon and activated alumina 8 , utilization of various agricultural waste for AC preparation and application for removal of dyes and metal ions from aqueous solution 9,10 , and a review on low cost adsorbent for waste and wastewater treatment 11 . Some other studies include review on decolourisation of dye solution by low cost adsorbents 12 , comparative study on adsorption kinetics and thermodynamics of dyes onto acid activated low cost carbon 13 , AC synthesized from agricultural waste have been used widely for removal of heavy metal ions 14-18 and continuous removal of chromium from tannery wastewater using activated sludge process- determination of kinetic parameters 19 . This study presents development of economical method for tannery wastewater treatment 20 using adsorption for decolourisation of common collection tank (CCT) & chromium tank (CT) wastewater samples, reduction of COD from lime water collection tank (LWCT) & CCT wastewater samples, and removal of chromium [Cr (III)] from CT samples. Experimental Section ACs were synthesized by chemical and thermal conversion of rice husk, saw dust and sugarcane baggasse. CCT, LWCT and CT wastewater samples were collected from a tannery unit. Known quantity of saw dust activated carbon (SDAC), rice husk activated carbon (RHAC) and sugarcane baggasse activated carbon (SBAC) was added to known volume of wastewater samples kept in separate beakers. Mixtures were stirred for several hours and kept still for 2-3 days. All samples were analyzed for COD [IS: 2488 (part 5)- 1976] and Cr (III) [IS: 3025 (part 52)-2003].