Table 1.
Mutagenicity of the untreated and the treated combined effluent as tested by the Ames test.
| Sample | No. of colonies | ||||
|---|---|---|---|---|---|
| Plate 1 | Plate 2 | Average | Normalized# to control | % inhibition | |
| Control (Spontaneous revertants) | 81 | 35 | 58 | - | - |
| Combined effluent (untreated) | ~5,000 | ~5,000 | 5,000 | 4,942* | 100 |
| Permeate, HRT 1.5 h | 397 | 371 | 384 | 326 | 6.6 |
| Permeate, HRT 4.0 h | 344 | 328 | 336 | 278 | 5.6 |
| Permeate, HRT 6.0 h | 250 | 208 | 229 | 171 | 3.5 |
| Permeate, HRT 6.0 h (continuous operation) | 204 | 157 | ~180 | 122 | 2.5 |
The permeate samples are from either the batch operation at the indicated HRT or from the continuous operation. *This is taken as a 100% inhibition value. The inhibition of the treated samples is compared to this value for determining % inhibition. #The number of spontaneous revertants obtained in the control sample is subtracted from the average of the sample colonies.