Abstract:
The dairy industry, a critical sector for food production, is recognized as a signihcant
contributor to water pollution due to its substantial water usage and high organic wastewater
loads. Fonterra Brands Lanka, a leading dairy producer in Sri Lanka and a subsidiary of
Fonterra, a global dairy exporter, faces the challenge of managing its wastewater effectively.
This research investigated the performance of the Fonterra Brands Lanka effluent treatment
plant (ETP), which employs a multi-stage process including screening, ef{luent collection,
dissolved air flotation (DAF), anaerobic treatment, aerobic treatment, clarification, sludge
treatment, and disinfection. The objectives of this study are to assess the efficiency of the
effluent treatment plant in removing pollutants such as BOD, COD, pH and total nitrogen
from dairy wastewater. The study evaluated four key water quality parameters: Chemical
Oxygen Demand (COD), Biochemical Oxygen Demand (BOD), Total Nitrogen (TI.{), and
pH over four days, collecting samples from eight designated points within the ETP.
Statistical analysis revealed significant variations (p < 0.05) in influent wastewater
characteristics. The wastewater treatment system demonstrated exceptional overall removal
efficiencies, achieving I00o/o for BOD, 99.33oA for COD, and 97 .29o/o for TN. The DAF
unit achieved up to 72.09a/o BOD and 62.120 COD removal, although its perloffnance
dropped on certain dates, while the denitrification tank showed fluctuating results, with
60.na COD removal and a significant drop to 36.2o/o for BOD rem-oval on certain dates.
The aeration tank and circular clarifier performed consistently well, achieving 77.8o/o and
up to 954/o BOD removal, respectively. pH levels fluctuated between 2.8 and 8.5 across the
treatment stages, with the inlet pH ranging from 2.8 to 6.8. These findings reflect the
treatrnent system's variable performance, largely driven by fluctuations in influent
composition and the effectiveness of individual treatment units.
