Wet-Weather Overflow at a Generator-Dependent Lift Station
A 1.8 MGD residential lift station serves 2,100 homes through 26 miles of 8- to 15-inch vitrified clay and concrete pipe, much of it installed in the 1960s. The station has two 75-hp pumps, a wet well that holds about 20 minutes at average flow, and telemetry that calls the duty operator's phone. On a Saturday at 3:10 a.m., 2.8 inches of rain falls in 90 minutes. By 4:05 a.m. both pumps are running continuously, the wet well is at the high-level float, and the alarm fires. The operator arrives at 4:40 a.m. to find sewage running out of the wet well hatch, down a 60-foot driveway, and into a roadside ditch that reaches Mill Creek about 1,200 feet downstream. The standby generator did not start; the starting battery is dead. A rented pump arrives at 7:30 a.m.; by then an estimated 8,000 gallons have discharged. A homeowner has already posted photos on social media.
1. List your actions for the first two hours in order, with the reasoning behind the sequence.
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Safety first: barricade the area, keep people and vehicles out of the spill path, and confirm no one is in the ditch. Then stop the source, because every minute of overflow adds volume. Get the generator running with a jump or a replacement battery, put the rented pump and a vacuum truck on the wet well, and if the downstream manhole can take it, set up a bypass so the station is not the relief point. Recovering sewage at the source with a vac truck beats trying to clean a ditch.
Contain what has already left: sandbag or earth-dike the ditch to stop flow reaching Mill Creek, and keep absorbent material on hand. Do not treat the ditch with lime and call it disinfected; lime is not a disinfectant and it does not fix the bacterial load. Sample the ditch and Mill Creek upstream and downstream of the entry point for fecal coliform and ammonia, because ammonia is a good sewage tracer. Photograph everything, log times, and start the volume estimate while the evidence is fresh, because the report will require it.
2. Who gets notified, when, and what does the written report need to contain?
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Ohio requires overflow notification to the Ohio EPA and the local health district, with the verbal or initial notice on a short clock (roughly 24 hours) and a written follow-up within about five days; confirm the exact deadlines and required form in your current permit and the state's overflow reporting rule, because the details are what get cited. Do not wait for the volume estimate to be final; report with what you know and amend later.
Before you call, check whether any public water system intake draws from Mill Creek downstream, and if so, call that system directly and immediately, because that is a potential drinking water exposure and it moves ahead of paperwork. Also notify your own management, the county emergency management agency if the spill reaches a road or a park, and any downstream property owner whose land the ditch crosses.
The written report should state the location and time of the release, the estimated volume and duration, how the volume was estimated, the receiving water and distance, the cause including the generator failure, the containment and recovery actions, sampling results, and the specific corrective actions with dates. Attach photos and the telemetry alarm record. Social media attention is not a reason to delay the report; it is a reason to make the public statement consistent with what you told the agencies.
3. What does a 2.8-inch storm in 90 minutes tell you about this collection system, and what do you propose for next year's budget?
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The station is being asked to pass stormwater, not just sewage. Compare the actual peak inflow against the dry-weather flow: 1.8 MGD average is about 1,250 gpm, and the fact that two 75-hp pumps could not hold the wet well during a short, intense storm means peak wet-weather flow is several times average. That ratio is the classic signature of infiltration and inflow, and in 1960s vitrified clay with open joints and cracked concrete, infiltration is expected. The driveway that carried the overflow also suggests private source connections, such as sump pumps and footing drains tied to sanitary laterals.
For the budget, propose flow monitoring at key sub-basins during wet weather to locate the sources, then smoke testing and manhole inspection to find direct connections. Pair that with a capacity project: either storage at the station or a larger force main, sized against a defensible design storm. The cheap, high-value items are monthly generator exercise under load with automatic-transfer testing, battery replacement on a schedule, and alarm escalation to a second number so a single missed call does not become a spill. Put the overflow volume and the cost of the fix in the same memo; that is what gets funded.