| Negative control | Positive control | Test |
| ||||||||
| Day zero | Day 7 | Day 14 | Day zero | Day 7 | Day 14 | Day zero | Day 7 | Day 14 | |||
Parameters |
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|
| |||||||||
pH | 7.5 | 7.5 | 7.5 | 7.5 | 7.5 | 7.5 | 7.5 | 7.5 | 7.5 | |||
Odour | D | D | D | D | A | A | D | A | A | |||
Suspended solids | N | N | N | N | N | N | N | N | N | |||
Colour with naked eyes | Dirty green | Dirty green | Dirty green | Dirty green | Brown | Brown | Dirty green | Brown | Yellow | |||
True colour with photometer (PCU) | 3030 | 3000 | 2970 | 3030 | 2200 | 2100 | 3030 | 2110 | 1680 | |||
COD (ppm) | 39177 | 38790 | 37763 | 39177 | 38040 | 33110 | 39177 | 34140 | 31000 | |||
Flocculationby wet mount | − | − | − | − | + | + + | − | + | + + | |||