Investigating the efficiency of rice husk ash as adsorbent in dye removal from textile wastewater : case study : Fine Spinners Uganda Ltd

Abstract

Advanced waste water treatment techniques such as adsorption are economically and environmentally essential in the removal of non-biodegradable toxic compounds from industrial wastewater. The research study focuses on the use of rice husk ash to treat textile waste water. Samples of textile wastewater were collected from the final clarifier of Fine spinners Uganda LTD and rice husks were got from local rice milling machines in Busitema trading centre, Batch tests were performed to investigate the use of rice husk ash as a potential adsorbent for dyes. Adsorption capacity was found to vary with PH, temperature; adsorbent dosage and contact time, the adsorbent was analysed by using FT-IR analysis technique which was done at Uganda Industrial Research Institute laboratories. The experimental result shows that RHA has good potential to remove dyes from effluent and good potential as an alternative low cost adsorbent. Experiments were carried out in triplicates and average value computed for each. The volume of wastewater samples were kept constant throughout all experiments at250mls. Initial conditions of the wastewater were measured and found to be concentration of 10000g/litre, temperature of 26°C and pH of 6. In all experiments, a sample of original wastewater was included, to which 110 RHA added so as to act as a blank solution. This was meant to be a control experiment and confirm that the observed results in actual experiment are actually due to the presence of the adsorbent, RHA and as well investigate whether there was any adsorption at the walls of the conical flasks. The alternative experiments had adsorbent RHA added to the wastewater to act as actual experiment. From the experimental Investigations the maximum percentage removal for dyes in textile industrial wastewater was calculated and obtained at an optimum bio-adsorbent dosage of 20mg, an optimum contact time of 15O minutes an optimum temperature of 40°C and an optimum pH of 5. The combination of optimum conditions yielded a percentage removal of 93.03% which is promising. The results obtained can help to design an appropriate wastewater treatment plant to minimize the adverse impacts caused by textile industrial wastewater.