Pollution Abatement in Milk Dairy Industry

The dairy industry involves processing raw milk into products such as consumer milk, butter, cheese, yogurt, condensed milk, dried milk (milk powder), and ice cream, using processes such as chilling, pasteurization, and homogenization. Typical by-products include buttermilk, whey, and their derivatives. The effluents are generated from milk processing through milk spillage, drippings, washing of cans, tankers bottles, utensil, equipments and floors. The dairy industry generate on an average 2.0-2.5 liters of wastewater per liter of milk processed. Generally this wastewater contains large quantities of casein, lactose, fat and inorganic salts, besides detergents, sanitizers etc. used for washing. These all contribute largely towards their high biological oxygen demand (BOD), chemical oxygen demand (COD) and oil and grease much higher than BIS permissible limits. Biological treatment appears to be the most promising technique, since diary effluents have low COD: BOD ratio. The effluents also contain required nutrient for microorganisms in sufficient quantities. Among the biological treatments trickling filter and activated sludge process involve more economy high power requirement, more chemical consumption and large area requirement. Using this as a starting point, we student decided to test the quality of effluent coming out from the dairy industry.