Abstract

The objective of this study was to ascertain the effects of pH and temperature on nutrient uptake efficiency of 3 wastewater protozoan isolates (Aspidisca (A), Trachelophyllum (B) and Peranema (C)) that have previously been screened for nutrient uptake ability. The study was carried out in shake flask at pH 5, 6, 7, 8 and 9 and incubation temperatures of 25, 30 and 35^oC for 96 h. The results revealed optimum pH ranges for the uptake of phosphate and nitrate to be 7 to 9 and 5 to 7, respectively. Maximum nutrient uptake was found to occur at 25^oC with phosphate concentration decreasing from 64.74 to 10.21 mg/l, 63.09 to 8.54 mg/l and 64.47 to 6.36 mg/l, for isolates ‘A’, ‘B’ and ‘C’, respectively. Also, nitrate concentration was found to decrease from 24.71 to 4.91 mg/l for isolate ‘A’, 24.47 to 11.15 mg/l for isolate ‘B’, and 24.58 to 15.00 mg/l for isolate ‘C’ at the same temperature. An increase in COD was observed in mixed liquor inoculated with the test isolates. The study has been able to give an insight into the optimum temperature and pH for phosphate and nitrate uptake by the isolates.

Key words:  Nitrate, pH, phosphate, temperature, uptake.