| Violation ID |
Occurred Date |
Violation Type |
(-) Violation Description |
Corrective Action |
Status |
Classification |
Source |
| 1125037 |
02/02/2024 |
CAT2 |
Chlorine, Total Residual 1-Hour Average (Mean) limit is 0.34 mg/L and reported value was 0.55 mg/L at EFF-001. |
The Chlorine Process Control Plan and sample line maintenance SOP have been updated, and operators have been trained to prevent recurrence. |
Violation |
B |
eSMR |
| 1124191 |
01/23/2024 |
DMON |
The Plant performed a titration but failed to properly record the data during the 0500 hour. |
The Plant increased the frequency of titrations to once every half hour. Following the incidents, notification was made to the RWQCB and the 5-day reports were waived. |
Violation |
U |
eSMR |
| 1124190 |
01/15/2024 |
DMON |
failure to perform the required hourly titration during the 0600 hour. |
Training all operators to remind them of the regulatory implications of failing to perform and record hourly titrations. |
Violation |
U |
eSMR |
| 1122963 |
11/26/2023 |
CAT2 |
Chlorine, Total Residual Instantaneous Maximum limit is 0 mg/L and reported value was 0.56 mg/L at EFF-001. |
This exceedance was caused by a fault in PCM-08. The ethernet card malfunctioned resulting in the stoppage of all sodium bisulfite pumps and the prevention of any audible alarms notifying operators of the failure. The faulty ethernet card was replaced as soon as it was identified as the source of failure. |
Violation |
B |
eSMR |
| 1122962 |
11/01/2023 |
CAT2 |
Chlorine, Total Residual Instantaneous Maximum limit is 0 mg/L and reported value was 0.1 mg/L at EFF-001. |
This exceedance seems to have been caused by flush water flowing through an offline pump into the common discharge. The excessive flow and pressure prevented adequate dosing of sodium bisulfite during this brief period; however, the pressure relief valve should have prevented this from happening. Operators have been provided additional training on the bisulfite system and flushing, as well as directed to exercise greater care when performing similar activities. |
Violation |
B |
eSMR |
| 1121955 |
10/27/2023 |
CAT2 |
Chlorine, Total Residual Instantaneous Maximum limit is 0 mg/L and reported value was 0.055 mg/L at EFF-001. |
This effluent excursion was caused by a contractor deviating from work scope and shutting down the lead SBS pump. Operations is required to read the excursion report and sign acknowledgement. Additional contractor requirements have been set in place for all work relating to existing equipment and processes. Daily 0600 activity meetings have been instituted, detailing work occurring for that day and what contractors are involved. |
Violation |
B |
eSMR |
| 1121954 |
10/12/2023 |
CAT2 |
Chlorine, Total Residual Instantaneous Maximum limit is 0 mg/L and reported value was 0.25 mg/L at EFF-001. |
Operations is required to read the excursion report and sign acknowledgement. Contractors are now required to verify all PLC rack slots and cards after completing work in any PLC. |
Violation |
B |
eSMR |
| 1121048 |
09/13/2023 |
CAT2 |
Chlorine, Total Residual Instantaneous Maximum limit is 0.0 mg/L and reported value was 1.35 mg/L at EFF-001. |
Training re-emphasizing shutdown startup procedures will be issued and reviewed with Operations. All chlorine analyzers, initials and finals, will be re-scaled to confirm 0.0 mg/L to 20 mg/L. |
Violation |
B |
eSMR |
| 1118641 |
06/27/2023 |
CAT2 |
Chlorine, Total Residual Instantaneous Maximum limit is 0.0 mg/L and reported value was 0.1 mg/L at EFF-001. |
Operations was required to read the 5-day report and sign acknowledgement. Additional training focusing on chemical response was captured in a Chemical Response SOP which was reviewed with Operations and equally signed acknowledging receipt. It is now standard practice during any chemical emergency to secure the effluent pump station, stopping all bay discharge, until the chemical emergency has been resolved. |
Violation |
B |
eSMR |
| 1106975 |
07/26/2022 |
CAT2 |
Chlorine, Total Residual Instantaneous Maximum limit is 0.0 mg/L and reported value was .85 mg/L at EFF-001. |
The 5-day report was issued to the Operations department for review and signature.
Additional training on SBS emergency response will also be emphasized to ensure future excursions of this nature do not reoccur. |
Violation |
B |
eSMR |
| 1106977 |
07/02/2022 |
CAT1 |
Carbonaceous Biochemical Oxygen Demand (CBOD) (5-day @ 20 Deg. C) Weekly Average limit is 25 mg/L and reported value was 27.4 mg/L at EFF-001. |
On Wednesday June 29, 2022 the debris was removed from secondary clarifier 3 rake arm and it was placed back into service.
To mitigate future secondary clarifier washout scenarios the secondary clarifiers will be taken offline one at a time.
In addition, the secondary clarifier removal from service SOP will be updated to reflect an SVI requirement of less than 220 mL/g along with a sludge settling requirement of less than 300 mL/L before a secondary clarifier can be removed from service. |
Violation |
U |
eSMR |
| 1106976 |
07/02/2022 |
CAT1 |
Total Suspended Solids (TSS) Weekly Average (Mean) limit is 30 mg/L and reported value was 41.5 mg/L at EFF-001. |
On Wednesday June 29, 2022 the debris was removed from secondary clarifier 3 rake arm and it was placed back into service.
To mitigate future secondary clarifier washout scenarios the secondary clarifiers will be taken offline one at a time.
In addition, the secondary clarifier removal from service SOP will be updated to reflect an SVI requirement of less than 220 mL/g along with a sludge settling requirement of less than 300 mL/L before a secondary clarifier can be removed from service. |
Violation |
U |
eSMR |
| 1106470 |
06/30/2022 |
CAT1 |
Carbonaceous Biochemical Oxygen Demand (CBOD) (5-day @ 20 Deg. C) Monthly Average (Mean) limit is 15 mg/L and reported value was 15.5 mg/L at EFF-001. |
On Wednesday June 29, 2022 the debris was removed from secondary clarifier 3 rake arm and it was placed back into service. To mitigate future secondary clarifier washout scenarios the secondary clarifiers will be taken offline one at a time. In addition, the secondary clarifier removal from service SOP will be updated to reflect an SVI requirement of less than 220 mL/g along with a sludge settling requirement of less than 300 mL/L before a secondary clarifier can be removed from service. |
Violation |
U |
eSMR |
| 1098821 |
12/23/2021 |
Order Conditions |
December 23, 2021, an unauthorized discharge occurred due to very high effluent flows which dislodged a temporary plug in a corroded automatic relief valve nozzle at the ARV#6 vault. The initial estimated unauthorized discharged quantity of 40-45,000 gallons reported to all required parties. The final discharge quantity of 158,400 gallons was reported in the 5-day report. The discharge took place over an 8-hour period.
During this 8-hour period the discharge occurred at effluent flows above 37MGD for 5.5-hours. |
During the event Operations reduced the effluent pumping temporarily by filling an offline aeration basin, but overall were unsuccessful in mitigating the discharge until the influent flows tapered off. A new welded suction ARV nozzle was installed in place of the corroded nozzle on 12.30.2021. Operators perform daily rounds at each ARV location twice per day. When flows are elevated above 25MGD the are required to perform additional rounds at the ARV#6 location. |
Violation |
U |
eSMR |
| 1098820 |
12/16/2021 |
Order Conditions |
The week of December 13, 2021, the Monday through Friday average effluent flow was 25.59 MGD with effluent flow peaks up to 50 MGD (normal average dry weather flows of 9 MGD). It is assumed but has not been confirmed that utilization of the final effluent storm pumps to handle the increased flows resulted in a discharge from an unknown location on the outfall pipeline between the final ARV#6 and the bay discharge. On December 16, 2021 water lightly bubbled up out of the soil near the ARV#6 vault into a curbed planter box and then onto a dirt utility road. An estimated 300 gallons was reported to all required parties. |
December 19, 2021 a full WWTP shutdown took place to perform an internal outfall inspection. All influent flow was backed up into the collection system or diverted to offline tankage to allow two divers to enter and inspect the outfall pipeline at ARV#6. This internal inspection did not identify the leak location. The ARV#6 vault and surrounding area is inspected twice per day as part of standard rounds. When the effluent flows are in excess of 25 MGD Operators are required to perform additional visual inspections. To date 1.7.2021 the leak location has not been identified but the COSM is actively pursuing numerous paths to confirm. |
Violation |
U |
eSMR |
| 1096360 |
10/25/2021 |
Order Conditions |
The City of San Mateo experienced a major storm event On October 24, 2021. On Oct 25, 2021, treated final effluent discharged onto East 3rd Avenue and into a City of Foster City storm drain. Per Foster City staff, this storm drain travels south and discharges into the San Francisco Bay via the Foster City Lagoon.
|
On October 25, 2021, the City of San Mateo Maintenance department dispatched Public Works Field Maintenance crews for support; two vac-con trucks arrived on the scene. Foster City staff was contacted and assisted with diverting the flow to a nearby sanitary sewer manhole; Two sump pumps were used to recover from the storm drain and pump to Foster City's sanitary sewer system.
On October 28, the City of San Mateo Maintenance crew replaced the outfall access hatch gasket and corroded bolts.
An annual integrity inspection PM will be generated for each of the City of San Mateo's outfall pipeline access hatches. |
Violation |
U |
eSMR |
| 1092275 |
06/18/2021 |
Order Conditions |
The unauthorized discharge event took place on Friday, June 18, 2021 at 0600, 0800, and 0945, at the City of San Mateo WWTP. Approximately 3,056 gallons of raw wastewater from a Foster City force main bypass, overflowed out of a manhole onto Detroit Drive.
The event was reported to the Case Worker by using the formal Five-Day Report on June 22, 2021. Please see attachment 2 in the June eSMR for detail. |
City of San Mateo's sewer maintenance crew and the contractor supplied vactor trucks and hydro-jetted and vacuumed the storm drain and another upstream storm drain. The contractor removed six to eight inches (8 cubic feet) of contaminated soil and capped with fresh soil.
WWTP staff, and the City's contractors visually inspected the storm drain discharge point to the San Francisco Bay and confirmed zero discharge.
For the next force main bypass the contractors were required to plug each storm drain and bolt on a flanged "sealed" piping system versus the open wetwell approach taken for this bypass.
Please see attachment 2 in the June eSMR for detail. |
Violation |
U |
eSMR |
| 1077307 |
06/12/2020 |
Order Conditions |
On Friday, June 12, 2020 at the City of San Mateo WWTP, approximately 250 gallons of secondary pump pit sump discharge was pumped through a cracked 3" PVC line into our back alley. Approximately 50 gallons made its way under the fence and into Leslie Creek, which is currently dammed off from Seal Slough and is stagnant.
On Friday at 2015 Operations received a high-level sump alarm in the secondary pump pit. Upon investigation the sump was found to be locally off, the breaker de-energized, and an additional sump pump and hose routed to an offline tank installed. The supervisor failed to comprehend the situation as the breaker was de-energized and not LOTO. The Supervisor energized the breaker and set the pump to auto and watched the sump level drop. Upon exiting the secondary pump pit, he witnessed the sump discharge spraying into the back alley. By the time he made it back to the pump controls the sump had reached its low setpoint and shut off. The day shift failed to update the night shift of this damaged discharge line.
The secondary pump pit sits below sea level and receives salt water infiltration via floor drains. Two separate samples of the secondary pump pit sump were taken and analyzed by our Laboratory. The first sample, taken immediately after the discharge, is a more representative sample of what made its way into Leslie Creek as the sump still had a residual level. |
Operations is required to LOTO all equipment that is left out of service past their shift. The imperative nature of LOTO has been reiterated to the Operations department. All Shift Supervisor's and Op III's are required to read the previous crews log entries immediately after turnover. Ultimately, secondary pump pit sump discharge line, will be rerouted to a tank within the walls of the pump pit to remove any chance that this line will ever make its way to Leslie Creek again. |
Violation |
U |
eSMR |
| 1084545 |
06/12/2020 |
Order Conditions |
On Friday, June 12, 2020 at the City of San Mateo WWTP, approximately 250 gallons of secondary pump pit sump discharge was pumped through a cracked 3" PVC line into our back alley. Approximately 50 gallons made its way under the fence and into Leslie Creek, which is currently dammed off from Seal Slough and is stagnant. On Friday at 2015 Operations received a high-level sump alarm in the secondary pump pit. Upon investigation the sump was found to be locally off, the breaker de-energized, and an additional sump pump and hose routed to an offline tank installed. The supervisor failed to comprehend the situation as the breaker was de-energized and not LOTO. The Supervisor energized the breaker and set the pump to auto and watched the sump level drop. Upon exiting the secondary pump pit, he witnessed the sump discharge spraying into the back alley. By the time he made it back to the pump controls the sump had reached its low setpoint and shut off. The day shift failed to update the night shift of this damaged discharge line. The secondary pump pit sits below sea level and receives salt water infiltration via floor drains. Two separate samples of the secondary pump pit sump were taken and analyzed by our Laboratory. The first sample, taken immediately after the discharge, is a more representative sample of what made its way into Leslie Creek as the sump still had a residual level. |
Operations is required to LOTO all equipment that is left out of service past their shift. The imperative nature of LOTO has been reiterated to the Operations department. All Shift Supervisor's and Op III's are required to read the previous crews log entries immediately after turnover. Ultimately, secondary pump pit sump discharge line, will be rerouted to a tank within the walls of the pump pit to remove any chance that this line will ever make its way to Leslie Creek again. |
Violation |
U |
eSMR |
| 1077306 |
06/06/2020 |
CAT1 |
Total Suspended Solids (TSS) Weekly Average (Mean) limit is 30 mg/L and reported value was 39.6 mg/L at EFF-001. |
On Wednesday, 6.3.2020, a microscope examination revealed an excessive amount of filaments in the process combined with an SVI of 497. Operations started chlorinating the RAS and increased the WAS rate to remove the filaments from the system.
Since June 13, final effluent TSS has been continuously dropping down to less than 20 mg/L. In the latest two weeks of June, the daily TSS is stable within range 6-8 mg/L. The monthly average in June is 20.3 mg/L, which does not exceed the permit limitation. The plant has instituted an SVI rule. If the SVI exceeds 330mg/L for two consecutive days and the effluent TSS is over 10mg/L we start chlorinating the RAS at 18lbs. |
Violation |
B |
eSMR |
| 1084544 |
06/03/2020 |
CAT1 |
Total Suspended Solids (TSS) Weekly Average (Mean) limit is 30 mg/L and reported value was 39.6 mg/L at EFF-001. *** MMP Exempt Reason:Duplicate of Violation 1077306. |
Since the weekly TSS excursion, the Plant has taken corrective actions including SVI policy as follows:
· Operations has instituted weekly process control meetings.
· Operations has issued an SVI policy detailing requirements when the SVI rises above certain control limits to start chlorinating the RAS.
· Operations has started performing weekly SOUR testing in the Aeration Basins.
· Operations started testing primary clarifier effluent for TSS and BOD. |
Violation |
B |
eSMR |
| 1070220 |
08/11/2019 |
Order Conditions |
On August 11, 2019, due to the failure of Chlorine Contact Tank #1 sodium hypochlorite feed pump on motor overload, approximately 300,000 gallons of non-chlorinated / non-disinfected effluent made its way to the San Francisco Bay via the outfall line. |
A weekly PM will be generated to confirm the standby HYPO feed pump is operable and ready for service as needed. |
Violation |
U |
eSMR |
| 1064629 |
08/11/2019 |
Order Conditions |
On August 11, 2019, due to the failure of Chlorine Contact Tank #1 sodium hypochlorite feed pump on motor overload, approximately 300,000 gallons of non-chlorinated / non-disinfected effluent made its way to the San Francisco Bay via the outfall line. |
A weekly PM will be generated to confirm the standby HYPO feed pump is operable and ready for service as needed. |
Violation |
U |
eSMR |
|
Report displays most recent five years of violations. Refer to the Interactive Violation Report for more data.
|
