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Facility Name:
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Shelburne 2 (Harbor Rd)
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Caller Name And Title:
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Chester A. Brigham III - Wastewater Superintendent
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Municipality:
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Town of Shelburne
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Location (street or site):
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Shelburne Wastewater Treatment Facility @ 53 Turtle Lane, Shelburne, VT 05482
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Incident Start Date:
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12/23/2025
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Incident End Date:
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01/02/2026
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Incident Start End Times:
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02:39 pm to 07:01 am
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Estimated Duration Of Event:
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Nature Of Incident:
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Discharged treated and partly disinfected effluent
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Estimated Volume (gallons):
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5916
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Cause Of Discharge:
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Other
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Type Of Obstruction:
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Point Of Discharge:
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WWTF outfall
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Corrective Action Taken:
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Upon receipt of the elevated E. coli result, operations staff immediately reviewed plant conditions and UV disinfection performance for the period surrounding the sampling event. A confirmatory effluent sample was collected approximately 34 minutes later, which returned within the range typically observed in recent monitoring. No operational upsets or bypass conditions were present, and discharge continued through the UV system.
Operators inspected the UV channels, verified lamp and ballast status indicators, checked flow pacing through the UV system, and confirmed acceptable effluent clarity and turbidity at the time of sampling. The event was documented, and effluent monitoring frequency was increased temporarily to ensure conditions remained stable.
As part of ongoing corrective work to improve disinfection reliability, we have ordered replacement UV quartz sleeves (delivery expected mid-January) and new ballasts, which will be installed upon receipt. The UV equipment manufacturer has been consulted and has offered bench testing of suspect components if needed. Until component replacement is completed, staff are maintaining conservative operating conditions through the UV system and are continuing close operational monitoring to prevent recurrence.
Following the event, two confirmatory samples were collected on 1/2/26, and both returned within permit limits, confirming that disinfection performance had returned to normal operating conditions.
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Waterbody Impacted:
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McCabe's Brook
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Contact Name And Title For Public:
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Chester A. Brigham III - Wastewater Superintendent
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Call Date:
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WW Staff Called:
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Type Of Notification:
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nForms
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Public Overflow Report For Web:
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Y
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Description Of Incident:
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On 12/23/25, two effluent E. coli compliance samples were collected approximately 34 minutes apart. The first sample (time 14:39) resulted in >400 MPN/100 mL, while the second sample resulted in 79.4 MPN/100 mL, which is consistent with recent values observed during ongoing UV system troubleshooting. Turbidity during the two samples measured 1.61 NTU and 1.52 NTU, respectively.
Based on operational review, the event appears to be associated with a brief and transient reduction in UV disinfection effectiveness during the first sampling period. The facility is currently evaluating potential contributing factors including UV ballasts and quartz sleeves, which are scheduled for replacement. UV lamps are within expected service life ( <6,000 hours used; manufacturer rating ~13,000 hours), and the manufacturer has not identified known lamp defects, though they have offered bench testing if needed.
Flow conditions at the time were within normal operating range; however, for reporting purposes, approximately 5,916 gallons have been conservatively assumed as potentially subject to reduced disinfection effectiveness during the incident window. The subsequent compliance sample indicated that conditions returned to typical levels shortly thereafter.
The exact root cause has not been definitively confirmed, and the facility is continuing review, component replacement, and verification testing. Additional exceedances are not anticipated based on current performance trends, but monitoring and troubleshooting remain ongoing.
On 1/2/26, two consecutive effluent E. coli compliance samples were collected and analyzed using membrane filtration, both of which were within permit limits. Based on these results, the incident period was closed and normal compliance conditions were verified
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nForm Submission Number:
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HQJ-3794-6TTY4
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