| Question - 1 of 12 | a | b | c | d |
| The operation log shows that the liquid in the aeration tank is slightly septic. The indication shows that ; | The plant is in an alkaline condition | The plant is operating properly and there are no indications that a problem exists or may develope | The influent wastewater is excessively acid at times | The influent wastewater is excessively alkaline at times |
| Question - 2 of 12 | a | b | c | d |
| This may be caused by ; | The plant is periodically receiving undesirable chemical waste | The plant is periodically receiving septic wastewater | The plant is periodically receiving alkaline wastewater | None of them |
| Question - 3 of 12 | a | b | c | d |
| When this problem exists you should ; | By - pass the plant | Report the suspected problem to the owner of the treatment facility | Add acid to the aeration tank | Reduce the air supply to the aeration tank |
| Question - 4 of 12 | a | b | c | d |
| If the problem continues and the owner of the treatment facility is not responsive to your reports, then you should ; | By - pass the plant | Consult the "Water Pollution Control Agency" for assistance in determining the source | Add acid to the aeration tank | Reduce the air supply to the aeration tank |
| Question - 5 of 12 | a | b | c | d |
| However, this is not always a simple choice or an action that should be taken without first advising the owner of the treatment facility why it is necessary to discover the source of the problem and your need for outside assistance to do so. While the problem exists you should ; | Decrease the rate of returning sludge | Add extra chlorine to the chlorine contact tank | Reduce the air supply as much as possible | Attempt to neutralize the excessive acid condition |
| Question - 6 of 12 | a | b | c | d |
| To return the plant to an allowable pH range it may be necessary to ; | Add acid to the aeration tank | Add lime to the aeration tank | Add chlorine to the aeration tank | By - pass the plant |
| Question - 7 of 12 | a | b | c | d |
| The lime should be added ; | In small doses (approximately 4.5 kg at a time) to the aeration tank | In a least one packed (25 kg) quantities to the aeration tank | In small doses to both the aeration tank and settling tank | In high doses only to the settling tank |
| Question - 8 of 12 | a | b | c | d |
| After the lime is well mixed in the aeration tank, you should ; | Perform a settleability test of activated sludge | Perform a dissolved oxygen test | Perform a pH test and add more lime if required | Perform a residual chlorine test |
| Question - 9 of 12 | a | b | c | d |
| As a general rule, the safe operating pH range for bacteria is ; | 8.5 - 9.5 | 5.5 - 6.5 | 4.5 - 6.5 | 6.5 - 8.5 |
| Question - 10 of 12 | a | b | c | d |
| The operation log also indicates that aside from the periodic undesirable chemical discharges, the influent wastewater is normally in a slightyl acid condition. The cause of this is probably due to ; | An after effect of the chemical discharges | Septic conditions in the wastewater collection system | Alkaline discharges | None of them |
| Question - 11 of 12 | a | b | c | d |
| Septic conditions can be expected to be most common ; | In the summer when the outside and water temperatures are higher | In the winter when low temperatures kill the bacteria | In the winter when the outside and water temperatures are lower | None of them |
| Question - 12 of 12 | a | b | c | d |
| A septic condition causes an increase in the demand for oxygen and normally results in a slightly acid pH. An unacceptably low pH, resulting from some chemical waste discharge, causes a reduction in the demand for oxygen because ; | The bacteria in the aeration tank begin to die and become inactive | It is usually only experienced in the winter months | Acids can substitute for oxygen and the bacteria will use the acid in place of oxygen | None of them |
