PROVINCETOWN — The “sewer emergency” — a cascade of wastewater problems that shut down most of the town’s central business district for all of Aug. 11 and 12 — began rather modestly, with a rainstorm on Tuesday, Aug. 9. It was a decent storm, the first real rain the Outer Cape had seen in weeks, but the power outage that came with it was almost subtle. The lights dimmed and brightened several times, in the flickery way of a scary movie, before going out completely and coming right back on again. In some parts of Commercial Street, power was cut off for only two or three seconds.
Outages like this are common here. At the town’s central vacuum station, a nondescript building near the municipal parking lot and the Peter Pan bus stop, however, something serious had happened. Director of Public Works Jim Vincent said the precise causes are still being investigated, but “something happened with the circuit breakers that was unusual.”
The main control panel in the vacuum station is covered in flashing lights that show the status of various parts of the system, Vincent said. When DPW engineers arrived around 4:30 p.m. Tuesday, the entire panel was dark. “There was nothing on the board,” said Vincent. “It was all out.”
The vacuum sewer system serves almost 600 properties in the center of Provincetown, including nearly every business on Commercial Street, a significant chunk of Bradford Street, and hundreds of homes on the small streets that connect them. Wastewater was still flowing into the system as intended, pulled by gravity to the 365 valve pits that lie beneath iron manhole covers in the town’s paved streets. But no wastewater was flowing out of those pits. The vacuum system that is automatically triggered when wastewater pools in these pits, whisking it away like the pressurized toilet in an airplane, wasn’t responding.
“We were down for a couple of hours” before an electrician got the central vacuum station powered back up, Vincent said. Town staff had alerted some nearby restaurants to be watchful for wastewater backing up into their sinks and dishwashers — a huge health risk — and a few venues closed early that night as a precaution.
Once the vacuum station was back on, however, town staff were optimistic that they could clear the backlog of wastewater. An alert from town hall on Tuesday evening said that isolated issues could exist along the vacuum line and that it could take several hours to be sure the reactivated system was working properly — but there were no reported overflows.
As engineers moved from valve pit to valve pit, following the main lines outward from the central station so as to restore vacuum pressure along the line, they kept finding trouble, Vincent said. Some pits were so full of wastewater that the electrical controllers were submerged and damaged. Others had valves stuck in the open position, preventing the drainage lines from holding pressure. Some controllers could be repaired, while others needed to be replaced.
Repairs were proceeding on Wednesday, Vincent said, but as the town filled up with people and inundated the system with more wastewater, the work that had been done was coming undone.
“Wednesday came, and it was such a busy day, it felt like a Carnival day,” said Vincent. “The streets were packed — it was the first cloudy day in a long stretch — and the high volume of flow was overwhelming the progress they had made.”
Controllers that had already been fixed were breaking again, as valve pits filled up with fresh wastewater. Commercial Street was also physically crowded.
“We had pump trucks surfacing sewage, and people crawling into manholes, and so many people around them,” said Vincent. Thursday was forecast to be even worse, with rain forcing people off the beaches and into the town’s commercial district.
“We were backsliding,” said Vincent. Too much of the system wasn’t functioning, and incoming flows were enormous. “By Thursday morning, there was no other way to fix the system,” he said, than to radically curtail the incoming flow of wastewater.
The sewer emergency was declared Thursday morning — first in an alert from Town Manager Alex Morse and then at a joint meeting of the select board and board of health. Residents served by the vacuum system were told to cease dishwashing, laundry, and showering, and to flush “only when absolutely necessary.” Restaurants and food service businesses in the affected area were closed entirely, with an exception for retail outlets to sell groceries.
Eighteen porta-potties were set up on Ryder Street outside town hall. The sewer emergency was advertised on electric signs up and down Route 6 to discourage people from coming to town. The initial announcement estimated it would take 48 hours to get the system back to normal.
In the end, it took a little less than that. Residential users were told at 6 p.m. Friday that they could “gradually return to normal water use,” and businesses were told that they could expect to reopen Saturday morning. The two-day shutdown had caused a great deal of lost income — but at least it did not extend into Carnival week, the year’s busiest, which began Saturday.
A modernization of the vacuum system was already set to take place this fall, funded by $2.2 million from the Cape and Islands Water Protection Fund, Vincent said.
A much larger project to sewer all of the remaining unsewered parts of Provincetown — estimated to cost $75 million, though a third of that would come from federal grants — is designed entirely as a gravity system, Vincent said. Some low-lying properties will need a grinder pump to send their wastewater uphill to the nearest sewer main, but the expansion will not enlarge the vacuum system.
Vacuum systems are not outdated, Vincent said, although they are more common in Europe than in America. A gravity system would have been extremely expensive on Commercial Street, he added. “You’d have to dig significantly deeper, under narrow streets, with high density and groundwater, historic buildings, and utility poles” to make a gravity system work in that area, Vincent said.
“Provincetown is a complicated geography,” Vincent added. Less dense parts of town can run on gravity while the central district remains a vacuum system.
Vincent also said that stormwater runoff was not a particularly large factor in this event. Stormwater is not supposed to enter the wastewater system, although it has happened at least once when a 2017 rainstorm created a clear spike in volume at the wastewater treatment facility, Vincent said.
There may have been some stormwater runoff in some of the valve pits, Vincent said, but there was not a geographic pattern that suggested stormwater had overwhelmed the sewer. Even though the rain was mighty and the power outage brief that Tuesday afternoon, it was the electricals that brought the sewer system to a halt — and it was a human tide that made it so difficult to get it going again.
