IACSIT International Journal of Engineering and Technology, Vol.2, No.5, October 2010 ISSN: 1793-8236 468 Abstract—The use of low cost, recycled waste and eco-friendly absorbent has been investigated as an alternative process for replacement of currently expensive process for removing dyes from wastewater. In this study, Acid activated saw dust was used to remove dyes from aqueous solution in a column filtration reactor. Saw dust is an excellent low cost adsorbent of colored organic anions and may have significant potential as a color removal from tannery wastewater. The effectiveness of acid activated sawdust in absorbing Lurazol Brown pH (LBP) dye from aqueous solutions was studied as a function of agitation time, adsorbent dosage and initial dye concentration. The experimental data were fitted to Langmuir and Freundlich isotherm and found that adsorption process follows both the isotherm. The values of Langmuir and Freundlich constants indicate favorable and beneficial adsorption. A two-stage treatment system was developed and its performance assessed in relation to a variety of initial dye concentrations. This was backed by a series of laboratory experiments, the results of which provide a better scientific understanding of the biodegradable material like acid activated sawdust and help realize their potential as commercial products. Index Terms—Dye Removal, Column Filtration Reactor, Biodegradable, Adsorption. I. INTRODUCTION Color organic effluent produced in the textile, paper, plastic, leather, food and mineral processing industries are high volume, hazardous and toxic waste. Among various industries, textile industry ranks first in usage of dyes for coloration of fibre. Today more than 9000 types of dyes have been incorporated in the color index [1]. Due to low biodegradability of dyes, a conventional biological treatment process is not very effective in treating a dye wastewater [2]. The conventional methods of removal of dye using alum, ferric chloride, activated carbon, lime etc. are not economical. Morris and Weber suggested that adsorption is a physiochemical treatment process, which has gained lot of attraction for the removal of dyes from wastewater since it produces a high quality treated effluent [3] and [4]. The most widely used adsorbent for industrial application is activated carbon [5], [6] and [7]. But the cost of the activated carbon is high and it increases with its quality. Ample research and Department of Mechanical Systems Engineering, University of the Ryukyus, Nishihara, Okinawa 903-0213, JAPAN, E-mail: rahman_942000@yahoo.com investigations have been carried out in different part of the world for the search of low cost adsorbents suitable to remove dyes from wastewater. V.K. Gupta and Suhas examined Application of low-cost adsorbents for dye removal– A review and demonstrated that among various methods adsorption occupies a prominent place in dye removal [8]. The growing demand for efficient and low-cost treatment methods and the importance of adsorption has given rise to low-cost alternative adsorbents. Agricultural solid waste such as coir pitch, banana pitch, coconut husk, rice husks, fly ash, Bagasse pith and sawdust etc have been investigated for the removal of dyes from wastewater[9], [10], [11], [12], [13] and [14]. Hardwood sawdust is a very cheap and easily available material in developing countries like India; Bangladesh has not been investigated with much attention for its possibility as an adsorbent. Though Asfour et al. has reported that the application of hardwood sawdust for the removal of some basic dyes from wastewater and their results give positive indication of use of sawdust as an effective and economical adsorbents [15] but so far our knowledge goes no works are available for the removal of acid dyes and reactive dyes from wastewater stream using sawdust. It seems that the extensive work is still required especially for acid dyes and reactive dyes before using it as a practical adsorbent. Thus the objective of this study is to explore the feasibility of using acid activated sawdust, as an adsorbent for the removal of Lurazol Brown PH (LBP), acid dye from aqueous solutions, which is widely used in leather processing industries. In order to demonstrate solvents performance, and to determine optimal design and operating conditions for a two-stage wastewater treatment system, the investigations were divided into two consecutive phases; i) laboratory tests and ii) two-stage treatment unit design and construction and operation of the two-stage unit. Saw dust is a waste by-product of the timber industry that is either used as cooking fuel or a packing material. In this work, we investigated the adsorption of malachite green by saw dust pretreated with formaldehyde and sulphuric acid. The influences of dye concentration, adsorbent dose, pH and contact time were investigated. II. EXPERIMENTAL METHODS Hardwood sawdust was collected from a local sawmill and dried in air at room temperature for some day and larger particles were removed with a sieve of size 200μm. Small Low Cost Biodegradable Adsorbent Material for the Removal of Dissolved Dyes from Aqueous Solutions: An Economical Process Rahman Muhammad Bozlur, Shinichi Shibata, CSiddiqua Farah Diba and Magali Uono