A case study on algal response to raw and treated effluents from an aluminum plating plant and a pharmaceutical plant

The algal growth responses to the effluents of an aluminum plating plant and to the wastewater from an analgesic/antiinflammatory-drug-producing pharmaceutical plant were investigated. Growth response of the marine alga Dunaliella tertiolecta was monitored by measuring the two response parameters optical density (OD640) and in vitro chlorophyll fluorescence for a period of 14 days. Generally, the two response measurements gave similar results for all effluents but the raw effluents of the aluminum plating plant due to the composition of the wastewater. All wastes affected algal growth either by inhibition only or by stimulation at low concentrations and inhibition at high concentrations. Since pollutant tolerance of algae biased toxicity test results, acclimation of algae to the raw effluent of the aluminum plating plant was examined. Although the water quality parameters of treated effluent of both plants were in the permitted range reported by the Turkish Water Pollution Control Act, they inhibited growth at higher concentrations, implying that the two treatment plants were inefficient. Therefore, the importance of toxicity tests in wastewater discharge regulations was emphasized.