Wastewater Characterization in a Multiproduct Dairy

Abstract

Wastewater characteristics in a multi-product dairy plant were determined in two major drains and for several operations. Monitored characteristics included flow, biochemical oxygen demand, chemical oxygen demand, total suspended solids, total solids, fat, and temperature. Overall, 2.3 liters of waste-water/kg of product were discharged with average concentrations of 3049 mg/liter biochemical oxygen demand, 5451 mg/liter chemical oxygen demand, 2203 mg/liter total suspended solids, 9574 mg/liter total solids, and 1424 mg/liter fat. The biochemical oxygen demand coefficient was 6.91 g/kg of product. Day-to-day variations of waste load/unit product were large. Peak day measures were more than 10 times as high as minimum day measures. Waste load discharged from the plant was related to losses of milk and fat. Losses of milk and milk fat calculated from waste characteristics were greater than indicated by plant records. Municipal charges for water, sewer, and surcharges for a plant processing 200,000 kg of product per day with the average characteristics in this study were predicted to be approximately $18,600 per month. Waste loads for selected operations are presented with suggestions for reduction. © 1979, American Dairy Science Association. All rights reserved.