Quick Boiler Replacement Avoids Sepsis

Replacing a wastewater treatment plant’s compromised, 1999, firebox-style boiler with a tube leak.

**FIGURE 1. The old, compromised, 1999, firebox-style boiler that once sat at the local wastewater treatment plant.**
*All images courtesy of Cole Industrial*

Over the summer, a member of Cole Industrial’s service team contacted a local municipality regarding its wastewater treatment plant (WWTP) to evaluate a compromised 1999, firebox-style boiler. The boiler was built to be a dual-fuel system capable of digester biogas and natural gas firing. The system had a newer fuel train and burner installed in 2015 but was ultimately a continuing problem, finally resulting in a moderate yet concerning tube leak starting early in 2023 and gradually getting worse. The primary factor for success was the recovery of thermal input to the WWTP’s digester systems. During summer months, required thermal input is reduced yet still very necessary to achieve 98°-99ºF optimal digester temperatures. Administrators made the decision to go completely off the digester biogas to avoid the continuing headaches of burning biogas and wanted to go to a clean, reliable, and efficient natural gas option.

Cole Industrial’s rental and new equipment sales groups teamed up to help the WWTP supervisor with some solutions. With the Cleaver-Brooks Clearfire CE boiler stock program and Cole’s repair division capabilities, the team could demo the current system; deliver, install, and commission a new CFC-E boiler; and recover thermal input to the city’s wastewater digesters before they dropped to critical temps of 85º and below. This is the point at which the sewage-eating microbiological “bugs” started dying off and the system became anoxic and septic, requiring a major expense to haul out the affected waste and an all-hands-on-deck situation to locate bugs from a nearby WWTP, seed the digesters, and slowly rebuild the biological base for them to recover and operate normally and at capacity.

The city was motivated to move forward, and the supervisor went to the mayor and city council to procure short-term funding with an emergency status project in hand. A city contract was delivered, reviewed immediately, and signed/returned to the customer the same day. The boiler was delivered from the Cleaver-Brooks stock program one week after the order. The new exhaust stack was not far behind. One complicating factor was the requirement to replace the stack with upgraded materials due to the new condensing boiler replacing a noncondensing boiler. This was not considered a complication for Cole Industrial’s repair division.

The repair group began work on the project and had the old boiler demolished and staged for removal on day one, much to the amazement of the city operations staff. Ancillary work continued into day two and, by day three, the new boiler had been set in place. By day six, the boiler had been fully piped into gas, water, and stack connections and wired by a city-provided electrical contractor. The city operations staff was reaching out to Cole Industrial’s service group for advice even before Cole’s technicians arrived to start up the boiler on day seven. The hydronic systems were then back online, and the bugs started getting comfortable again after experiencing some cooling down to about 89º. With some room, but not much to spare, the city’s WWTP operations staff slowly started bringing digester temperatures back up to the 99° sweet spot, and the systems smoothed out and have been working well ever since. Following up with commissioning, Cole’s service group provided a system check, handoff, and training session with the WWTP staff to complete the project.

Out with the old, in with the new

The whole project, including demolition, took only seven days. The final handoff to the customer was completed in just 13 days. The head operator has reached out to Cole’s service group by phone several times with questions since the startup, and Cole has been able to provide ongoing support. Not to mention, the WWTP supervisor had been on vacation during the entirety of the project. His staff wanted him to return to a successfully completed project, and they made it happen.

The supervisor reported back to the mayor and city council on the project’s success and his satisfaction, stating, “I’ve been telling everybody about this job and how the Cole team came through for us.”