Effluent Generation by the Dairy Units: Characterization and Amelioration for Irrigation

Abstract

A study was conducted to know the quality of effluent generated from the Mother Dairy, Yelahanka, Bangalore, Karnataka for the purpose of mitigating pollution. The methodology consists of collection of samples from the production unit and measuring the volume of effluent released out, per batch of processing of milk and also characterization of effluent was done as per the standard procedures. For amelioration, treatment methods like filtration through sand and clay filters, chemical coagulation and the combination of different treatments were followed. Results of the study revealed that, dairy units produce the effluent of exactly ten times of its production capacity (ten lakhs liters of effluent per day where the processing capacity is one lakh liters of milk per day). Dairy effluent was dark milky whitish in color, stringent smelling, which is slightly irritating and also contains fair amount oil. Dairy effluent posses all the characters of polluted water by having high pH, EC, BOD, COD, TSS, TDS and other plant nutrients. The effluent treated at dairy is also consist of huge amounts of pollutants. The methods followed for amelioration, improved the quality of effluent by reducing the pollutants present in it. Among different amelioration techniques physical filters followed by combination of different treatments are found to be most effective method in improving the quality of effluent. Among the different types of filters sand cum clay filter was found to be most effective filter in reducing the pH level to neutral, complete removal of oil, reduction of TDS and TSS by 68 and 74 per cent respectively, reduction of BOD and COD by 92 and 87 per cent respectively. From the study it was confirmed that treated effluent samples can be used safely for irrigation of crops as it meets the ISI standards.