WINONA, Minn. – A September fire at the Miller scrapyard was caused by improperly sorted waste material from the municipal sewage plant, said scrapyard owner Jeremy Miller. The city, said Miller can expect a $1.3 million bill from the scrapyard’s insurance carrier. Miller pointed to an investigative report from the insurer that blamed the fire on methane filters that had been hauled to the scrapyard before being cooled and aired out sufficiently. The fire started in a truck that had driven into the scrapyard. Only later did the fire erupt. Firefighters extinguished the blaze, but it reignited after fire crews thought it was out and left. The greatest damage was to a transfer station building and a warehouse. The scrapyard, on Shives Creek on the Far East End, is owned by former Mayor Jerry Miller and his son Jeremy, a state senator.
Sewage plant. Source of spontaneous combustion at Miller scrapyard has been traced to the Winona municipal wastewater treatment plant. At 1400 Shives Road. Image: Steve Lunde
Perils of chemistry
If damage was indeed due to spontaneous combustion from meyhane filters, experts say this could be what happened:
> Equipment at the wastewater plant captures methane gas from sewage and burns it to generate energy.
> The filtering material itself consists of iron oxide pellets that capture the noxious gas hydrogen sulfide.
> A chemical reaction between the hydrogen sulfide and iron oxide converts the pellets into iron sulfide.
> When the spent pellets are exposed to oxygen in the air, another chemical reaction generates heat.
> The reaction occurs slowly and can go unnoticed until it sparks a fire.
A fire that wouldn’t die
Firefighters knew the burning trailer was loaded general waste, including shredded fabric and filter media from the wastewater plant. They sprayed the truckload with water and pushed some persistently burning material into a pile near Miller’s transfer station ramp. The rest was off-loaded into a large structure, where crews spent two hours extinguishing it. Scrapyard workers later moved debris to the far east side of yard. It apparently relit itself five days later. Miller said the warehouse and transfer station will be rebuilt.
A disposal history
Miller Scrap has had a continuing contract to dispose of material from the wastewater plant. There never had been a previous incident, Miller said. In an interview with the Winona Post, the city’s wastewater supervisor, Paul Drazkowski, acknowledged that recent filters had performance issues and were retired earlier than the typical one to three years. The usual procedure for disposing of spent filters, he said, was to water them down and let them sit for a day to prevent spontaneous combustion.
Earlier: First fire crew locked out at Miller scrapyard