| Violation ID |
Occurred Date |
Violation Type |
(-) Violation Description |
Corrective Action |
Status |
Classification |
Source |
| 1136570 |
10/14/2024 |
OEV |
Total Coliform Not to exceed a specific limit more than once within any 30-day period. limit is 23 MPN/100 mL and reported value was 30 MPN/100 mL at EFF-001. |
Continue to maintain UV system. Investigate possibility of enclosing UV system. |
Violation |
U |
eSMR |
| 1126791 |
03/21/2024 |
DMON |
The minimum hourly average UV dose recorded was 96.23 mJ/cm2 the operating condition is no less than 100 mJ/cm2. |
A utility power failure that surged and single phased the plant on March 8th may have contributed to this event as it appears to have damaged components of the control system of the UV system. A 3 phase surge suppressor protecting the fire pump system had 1 phase that was destroyed in the event.
Staff found several communication control boards in the UV system that were burnt at the UV intensity (UVI) sensor terminals. The boards were communicating with the control system but were not reading the UVI signal from the UVI sensors. While the UVI data is important as an indication of the efficacy of the lamp sleeve cleaning system it is not used in dose calculations and is not a trigger of a critical alarm. The Trojan manual specifies that a low dose reading calls for all banks to start whether they have alarms or not so that a low dose never occurs. This did not happen in these events. We are working with Trojan UV technical support to troubleshoot the control system to ensure the system is doing what the manual specifies. We have replaced the damaged control boards and have not seen any low dose events since.
|
Violation |
U |
eSMR |
| 1126790 |
03/20/2024 |
Order Conditions |
The minimum hourly average UV dose recorded was 97.46 mJ/cm2 the operating condition is no less than 100 mJ/cm2. |
A utility power failure that surged and single phased the plant on March 8th may have contributed to this event as it appears to have damaged components of the control system of the UV system. A 3 phase surge suppressor protecting the fire pump system had 1 phase that was destroyed in the event.
Staff found several communication control boards in the UV system that were burnt at the UV intensity (UVI) sensor terminals. The boards were communicating with the control system but were not reading the UVI signal from the UVI sensors. While the UVI data is important as an indication of the efficacy of the lamp sleeve cleaning system it is not used in dose calculations and is not a trigger of a critical alarm. The Trojan manual specifies that a low dose reading calls for all banks to start whether they have alarms or not so that a low dose never occurs. This did not happen in these events. We are working with Trojan UV technical support to troubleshoot the control system to ensure the system is doing what the manual specifies. We have replaced the damaged control boards and have not seen any low dose events since.
|
Violation |
U |
eSMR |
| 1121575 |
09/07/2023 |
CAT2 |
Zinc, Total Recoverable Daily Discharge limit is 86 ug/L and reported value was 99 ug/L at EFF-001. |
Treatment plant staff is investigating this incident and has reviewed records to attempt to determine the cause. Aside from the zinc result no records appear out of normal range. No plant upset occurred around the date of this monitoring event and no influent changes were observed or detected in operational data. The last 5 years of zinc data were reviewed and charted. The chart is in the narrative attachment of this report
This 99ug/L result is more than 3 standard deviations from the 5-year average zinc discharge of 38ug/L, laboratory error is suspected. In observing the attached chart one thing stands out; month to month deviation of the data in 2023. Due to consolidation in the contract laboratory industry in 2022 the lab Atwater was using was purchased and became unable to provide timely reports. This led Atwater staff to change laboratories and in January 2023 the current contract laboratory began analysis for Atwater. In an upcoming sampling event, treatment plant staff plan to split the effluent zinc sample and send it to the two different contract laboratories. The results will be entered in the respective monthly report and a determination will be made whether to change laboratories again to attempt to provide the most accurate data possible.
|
Violation |
U |
eSMR |
|
Report displays most recent five years of violations. Refer to the Interactive Violation Report for more data.
|
