Madu, K.1., Okoronkwo, G. O.2 and Okoronkwo, P. C.3
1Department of Mechanical Engineering Chukwuemeka Odumegwu Ojukwu University Uli 2Department of Chemical Engineering Chukwuemeka Odumegwu Ojukwu University Uli
3Department of Electrical and Electronics Engineering Chukwuemeka Odumegwu Ojukwu University Uli
Email: madukc@yahoo.com, ogeorgeonyeka@gmail.com and pamela.okoronkwo@gmail.com.
ABSTRACT
Food processing industries consume large quantities of water. The food industrial effluents in general are characterized by high Biological Oxygen Demand along with fats, oil–grease and many other recoverable nutrients like Nitrate and Phosphorous. In the present investigation thorough treatment studies were carried out on alkwa abattoir effluents in Anambra state, Nigeria using alum, as coagulant. Physicochemical characterization of the effluent was also carried out to check the pollution potential of this wastewater. More emphasis was given on the representative water parameters mainly pH, Electrical Conductivity, Total Dissolved Solids, Biological Oxygen Demand, Turbidity etc. The coagulation was performed with alum at different dosage intervals in order to check the variations in effluent parameters. Present studies revealed that coagulation has better ability to reduce the abattoir wastewater parameters.
Keywords: Abattoir Wastewater, Coagulation, Physico-Chemical Parameters, Statistical
Analysis.
1.0 INTRODUCTION
Ever increasing industrialization and rapid urbanization have considerably increased the rate of water pollution. The dwindling supplies of natural resources of water have made this a serious constraint for industrial growth and for a reasonable standard of urban living. The environmental protection agencies have imposed more stringent regulatory prohibitions to protect the environment. This has made the water treatment more expensive and to comply with the discharge quality standard itself, is becoming a huge burden for the industries. The pollution of water resources due to discharge of poor quality effluents poses a serious threat to human beings and aquatic organisms since they rely on water for sustenance. The problem is more severe in developing countries where rapid population growth and industrialization has increased complexity of effluents [1–3]. In recent years, researchers have shifted their interests in possible reuse and recycling of various effluents where food industries are no exceptions to it [4]. In most cases, these effluents are not treated and are simply thrown into rivers where they contribute to eutrophication by addition of phosphorus and nitrogen compounds. Treating food effluents is of crucial importance not only for the environment, but also for the purpose of recycling water for use in industrial processes. The physico -chemical processes suffer the disadvantage that reagent costs are high and the soluble COD removal is low [5]. Moreover, chemical treatments could induce a secondary pollution due to the fact that chemical additives may contaminate the treated water. Food industry wastewater demonstrates a complicated system containing different components, including pollutants coming from the processed raw materials, chemicals and residues of technological additives used in individual operations. In reference to food industry wastewater, treatment processes have to assure first of all required quality of discharged effluents.
Food industry is of crucial importance to India and contributes 35% of the total Asian food. It is the world’s largest food producer in the entire globe consuming almost 100% of its own food production. The food industries require large quantity of water for the purpose of washing of cans, machinery and floor, the liquid waste in a food originates from manufacturing process, utilities and service section. The clean water is used in various stages of food operations, such as, meat processing, cleaning, packaging and cleaning of the milk tankers and releases the wastewater which is known as food effluent. Water is used for processing in the ratio of 1:10 (water: milk) per liter of milk. Food wastewater has high concentration of dissolved organic components like proteins, lactose, fat and minerals [6] and it is also malodorous because of the decomposition of some of the contaminants causing discomfort to the surrounding population. The food industry generates huge amount of wastewaters, approximately 0.2–10 L of waste per liter of processed food [4]. Food wastes are largely neutral or slightly alkaline and have a tendency to become acidic quite rapidly, because of the fermentation of food sugar to lactic acid. The lower pH may lead to the precipitation of casein. Food wastes are characterized by strong butyric acid odor and heavy black flocculated sludge masses [7]. Fats, oil and grease, also called FOG and can have negative impacts on wastewater treatment systems [8]. Oil and grease is composed primarily of a fatty matter from animal and vegetable sources, hydrocarbons of petroleum origin, the interferences include sulfur compounds and certain organic dyes [9]. Organic load is basically constituted by food (raw material and dairy products), reflecting an effluent with high levels of chemical oxygen demand (COD), biochemical oxygen demand (BOD), oil and grease, nitrogen and phosphorus. Moreover, the automatic cleaning system CIP (cleaning in place) discards rinse waters with pH varying between 1.0 and 13.0, further complicating the question of treatment [10].
Alum (Aluminum sulfate) is a nontoxic material commonly used in water treatment plants to clarify drinking water. Cooke et al. [11] adopted 50 mg Al/l as a safe upper limit for post-treatment dissolved aluminum concentrations. Waste control is an important aspect of resource management control and an essential part of food plant operations [12]. Water management in the food industry is well documented, but effluent production and disposal remain a problematic issue for the food industry [13, 14]. Effects of the presence of these wastes include, contamination of drinking water, killing of aquatic life, increased danger in swimming and objectionable physical conditions such as off odors and accumulation of debris. Land disposal of farm effluents can cause water logging conditions and contamination of groundwater along with surface water by leaching and runoff in nearby areas. The chemical methods may cause further contamination to the environment and while breaking down the organic pollution, microorganisms deplete the oxygen from water [15].
In the present investigation, an attempt has been made to study the physicochemical characterization and effects of alum coagulation techniques on the selected abattoir food industrial effluents. The treatments were studied in relation with important water quality parameters mainly associated with estimation of pH, EC, TDS, BOD, Turbidity and etc. of the treated effluents.
