Wastewater management in food processing enterprises – a case study of the Ciechanów dairy cooperative

The paper reports on wastewater management in food processing enterprises, using the Ciechanów Dairy Cooperative as an example. The efficiency of preliminary treatment of wastewater entering the municipal sewerage system was evaluated using basic pollution indices for wastewater pre-treated in the process of chemical neutralisation as well as results of physical and chemical analyses of raw wastewater from fromage fraise and cottage cheese production lines. The number of exceedances of permissible values of pollution indices in pre-treated wastewater was determined based on values set in the water legal permits issued by the relevant authority. Pretreated wastewater entering the municipal sewerage system met the standards for permissible wastewater pollution indicators excluding BOD₅ (biochemical oxygen demand) and COD (chemical oxygen demand). Physical and chemical analysis was performed of total raw wastewater and wastewater discharged from fromage fraise and cottage cheese production lines. Pollution indicators (COD, total nitrogen, orthophosphates, total suspensions, fats, pH) had high values but they remained within the ranges typical for dairy food processing.