The very nature of the different operations involved in dairy, irrespective of the products size, generate waste water of different magnitude. Effluent Treatment Plant for Dairy is one of the major contributors among the food industry both in terms of value and effluent. The biggest share comes from cheese and ice cream factories. The relatively high concentration of organic matter in the dairy effluent makes it peculiar in its class and this results in a higher biological oxygen demand (BOD). This kind of effluent should not be allowed to mix up with the municipal waste as it will result in a shock load.
Great care has to be exercised while discharging the dairy waste water into the general pool as they impose relatively high oxygen demand. Lactose is converted into lactic acid resulting in decrease in its concentration, when dissolved oxygen is insufficient for oxidation.This in turn will lower the pH to a point when casein is precipitated (The isoelectric point of casein is at pH 4.6). Due to economic reasons involved in the effluent treatment, the dairy industry is very slow in taking up the treatment aspects. With increasing social awareness about the environment, the dairy industry is forced to treat its effluents effectively and efficiently before disposal into the public drainage.