J. of Bioprocessing and Chemical Engineering Volume 2 / Issue 1 ISSN: 2348 –3768 1 Biochemical Treatment of Aqueous Wastewater Effluents from a Local Textile Industry OSEH, Jeffrey Onuoma Department of Chemical and Petroleum Engineering, (Petroleum Engineering Programme), Afe Babalola University, Ado-Ekiti (ABUAD), Ekiti State, Nigeria. *Corresponding author: OSEH, Jeffrey Onuoma E-mail: jeffreydengr@gmail.com Received: August 20, 2014, Accepted: September 5, 2014, Published: September 6, 2014. ABSTRACT This work is concerned with the finding of the optimum conditions for biochemical aqueous wastewater effluents treatment for a local textile mill. The water samples were taken from the Sunflag Textile Mill, Lagos, Nigeria (the aqueous wastewater effluents of the fabrics, leathers, dyes and other solid waste) in equal volumes and subjected to incubation, sedimentation, biological treatment, chemical treatment, and chemical and natural sedimentation treatment. The Box-Wilson method of experimental design was adopted to analyze the physio-chemical and biochemical effects on the wastewater effluents. The physio-chemical and biochemical analyses carried out on the sample revealed that the most favourable optimum operating conditions for the treatment variables are: Temperature 34.5oC, Contact period 40 hours, PH 7.3, Biological Oxygen Demand 28.77 mg/l, Chemical Oxygen Demand 11.71 mg/l and Total Suspended Solid 26.51 mg/l. The analyzed study showed a result that meets the Federal Environmental Protection Agency and Lagos State Environmental Protection Agency effluents treatment standard. Keyword: Aqueous wastewater effluents, Biological Oxygen Demand , Chemical Oxygen Demand, Total Suspended Solid, Temperature, PH. INTRODUCTION In Textile Industry (fabrics) and for practical reasons, almost all textile mills are located on rivers to provide them with process water (30 to 80 m 3 for 1 ton of processed raw skins) [1] and for the disposal of their effluents. The effluent from this industry is mainly waterborne [2]. The components of the effluent arise from purification of raw fibers, dyes from colouring, hides and skins before processing as well as from residual chemicals from the production processes. Hence, the textile industry had been recognized as a major contributor to water pollution problems. Biodegradable organic matter consumes oxygen and nutrients in complex biochemical reactions until rendered inert [3]. This exerts a biochemical oxygen demand as one of the fundamental parameters used to regulate the quality of the effluent [4]. The contaminants in industrial wastewater are removed by physical, chemical and biological means [5]. Facilities for handling wastewater are usually considered to have three major parts: collection, treatment and disposal [6]. Pre-aeration is used to improve the wastewater and to assist the removal of oil and grease [7]. Secondary treatment processes commonly consist of biological processes. This means that living organisms which control the environment of the process are used to partially stabilize (oxidize) organic matter not previously removed by treatment processes and to convert it into a form which is easier to remove from the wastewater [8]. Sedimentation or primary treatment makes the wastewater much clearer. Two clarifiers are used [9] to provide detention time (3 hours) where, almost 60% of the suspended solids (SS) will either settle to the bottom or float to the surface and be removed. Removal of these solids will usually reduce the BOD of the waste approximately 35%. The next step is the biological treatment which can typically be divided into aerobic and anaerobic. Anaerobic biological treatment is an oxygen-devoid process. Aerobic biological treatment is done in the presence of oxygen. It is applicable to wastewater containing bio-degradable organic constituents and some non-metallic inorganic constituents [2]. The bacterium, Bacillus Subtilis using the Activated Sludge Process (ASP) is the currently used biological treatment process for wastewater in most textile and tanning factory in Nigeria. The system consists of an equalization basin, a settling tank, an aeration basin, a clarifier, and a sludge line. The recirculation of the biomass, which is an integral part of the process, allow microorganisms to adapt changes in wastewater composition with relatively short acclimation time and also allow a greater degree of control over acclaimed bacterial population [10]. For a proper control of the ASP, the growth of the micro-organisms should be controlled. Bacteria make up about 95% of the activated sludge biomass. These single celled organisms grow in the wastewater by consuming (eating) biodegradable materials such as proteins, carbohydrates, fats and many other compounds. Some important factors acting on growth and activity of bacteria in biochemical wastewater treatment are: food-to-microorganism ratio (F/M); use of oxygen [11]; formation of Floc [12]; mixing [12]; P H [13]; temperature [6] and the effect of nutrients [14]. Biological oxygen demand (BOD) is a measure of the oxygen used by JOURNAL OF BIOPROCESSING AND CHEMICAL ENGINEERING Journal homepage: http://scienceq.org/Journals/JBCE.php Research Article Open Access