| Question - 1 of 4 | a | b | c | d |
| Which of the followings is the cause of the filamentous bulking sludge ? | Low dissolved oxygen concentration | High S-2 concentration | High F : M ratio | All of them |
| Question - 2 of 4 | a | b | c | d |
| What is the cause of the bulking sludge originated from the fungus ? | Low dissolved oxygen concentration | High S-2 concentration | Low pH (4 - 5) | All of them |
| Question - 3 of 4 | a | b | c | d |
| How can you recognize that your plant has filamentous bulking sludge or fungal bulking sludge ? | By pH test | By 30 - minute settling test | By microscopic examination | All of them |
| Question - 4 of 4 | a | b | c | d |
| If your plant has filamentous bulking sludge, what should you do ? | Chlorination the sludge returning line | Adding chemical coagulants into the settling tank | Operating the selector if it is available | All of them |
