United States Distilled Products (USDP) is trying again to see if it can successfully send wastewater from its main operation to the city’s wastewater plant by first pretreating effluent from USDP’s liquor-mixing and bottling plant.
It began a second attempt starting near the end of May, after having problems in its first test run about a month earlier.
USDP was granted the city’s permission some months ago to send a limited amount of its plant’s wastewater to the city’s wastewater processing plant by first pretreating it. USDP began a trial run for nearly a week starting in late April. The city halted it when it discovered that the amount of phosphorous in the wastewater had spiked far beyond the allowed limits in the city’s permit.
USDP located in the industrial park in 1981 and ever since then has been trying to see if it could somehow send wastewater to the city’s wastewater plant rather than having to haul it elsewhere. It has been hauling its wastewater to either a hybrid lagoon setup at Zimmerman or to a wastewater plant at St. Paul.
About six months ago USDP set up a pretreatment facility in a building in its complex. It consists mainly of nine 6,000-gallon tanks, and a few smaller pieces of equipment, along with a pumping mechanism and electronic monitoring equipment.
USDP Director of Operations Jon Nordman gave the Union-Eagle a tour of the pretreatment plant recently. It is in a building once used as a machine shop business in the industrial park. The nine 6,000-gallon tanks are clustered together inside on one end.
Nordman’s tour actually began outside the building where he pointed to the ground. Two tanks sit there below the surface, he explained, one that holds 32,000 gallons of USDP wastewater and one that holds 12,000 gallons.
The larger one is a holding tank and the smaller one is called a batch tank. Wastewater from the holding tank is sent into the batch tank where water is added to dilute it to meet the parameters of the city’s permit.
The whole idea of pretreating USDP’s wastewater before sending it to the city is because of the “high strength” qualities of the wastewater coming out of the liquor-mixing plant. It’s high in sugar and alcohol and if there is too much of those properties that it overwhelms the bacteria in the city’s wastewater plant, the city plant could stop functioning, according to City Administrator Mark Karnowski.
USDP’s new pretreatment plant also uses bacteria, or microorganisms for breaking down the wastewater. Millions of bacteria are in the tanks in the USDP pretreatment plant, living off the nutrients and oxygen supplied to them. The nine tanks are grouped in threes. The first tank in each three-tank lineup is filled with wastewater from the batch tank outside the building. When the first of the three tanks gets to the overflow level, it runs into the next tank in line, and when the second tank fills up it flows into the third. Liquid, after more pretreatment in the third tank, goes to a sludge-settling tank before the remaining liquid is sent on its way. The pilot project allows USDP to send up to a maximum of 2,000 gallons per day of pretreated wastewater to the city’s wastewater plant
USDP, along with the city’s consulting engineers, closely monitors the qualities of the pretreated wastewater, Nordman said.
Besides making sure there is enough bacteria in the pretreatment tanks, air is also inserted through something called vacuum bubble technology, Nordman said, explaining that the oxygen helps feed the bacteria.
USDP has hired a testing company to maintain and operate the pretreatment plant and the city tests USDP’s pretreated wastewater independently of USDP.
Nordman indicated that a food for bacteria is sometimes put into a pretreatment tank to help the bacteria, but that not much of that is needed at USDP, he said. “Our waste is really clean so not a lot of food is added to promote growth (of the bacteria),” Nordman said.
To get the bacteria working initially at the USDP pretreatment plant, bacteria were hauled in from the wastewater facility at Zimmerman.
Any issues, including the one nearly a month ago when someone at neighboring Glenn Metalcraft called the police because of a bad odor coming from the USDP complex, were the kind of issues that come with starting up a pilot project, Nordman said. He said he didn’t know the precise cause of the odor, only that “the bacteria got shot by a slug of something. Maybe it was alcohol. I’m not sure.”
USDP is “committed to making it work,” Nordman said.
Princeton city officials have not indicated any problems with USDP’s most recent attempt to send pretreated wastewater to the city.
Nordman added that USDP studied the pretreatment technology “thoroughly,” and that this technology has been used at wineries on the West Coast.
Setting up the pretreatment plant was also expensive, Nordman said, explaining that it cost USDP “close to $1 million.”