City to treat USDP wastewater

The city has approved an agreement to take pre-treated industrial wastewater from the United States Distilled Products (USDP) plant as part of a pilot project, pending city attorney review.

The USDP plant sits prominently in the city’s main industrial park, with its large metal silo tanks, while the liquor scented air around it should be a tip-off to most noses as to what’s inside those tanks.

USDP, which mixes and bottles a variety of alcoholic beverages, is also a growing business with one large expansion going on and another being planned.

But until now, USDP has not been able to count on the Princeton wastewater processing facility to take USDP’s industrial wastewater. That effluent is rich in sugar and other nutrients that come from blending liquors and flavorings.

USDP officials had hoped about 16 years or so ago to send its industrial wastewater to the city’s wastewater facility but the city would not allow it because it would have been too much for its processing capabilities. USDP, therefore, has been taking all of its processing wastewater outside of Princeton for disposal. It has produced about 10,000 gallons of industrial wastewater per month recently, according to city public works director Bob Gerold.

The city’s first mechanical wastewater plant opened in 1995 to replace the city’s former lagoon system of treating sewage and now the wastewater plant is being expanded. The expansion project is scheduled to be completed about the end of this year.

There has been talk over the years about the idea of USDP building a pretreatment facility at its plant, but it wasn’t until recently that USDP has gotten close to trying that. The pretreatment facility, which is not quite finished, according to USDP official Todd Guisness, sits inside USDP’s nearly-completed plant addition.


The agreement

The amount of wastewater that the city’s wastewater treatment facility took in last month from the entire city was an average of 360,000 gallons per day, according to Gerold.

The agreement to take USDP’s pretreated wastewater requires both the city and USDP to do regular and frequent testing of the USDP effluent to make sure that it is of a strength that the wastewater plant can sufficiently handle. The agreement notes, for example, that if the city increases the frequency of those tests, USDP has to increase its testing.

Also, if there is an accident where a slug of high-strength wastewater should discharge from the USDP plant into a city wastewater main, USDP must notify the city immediately.

The plan is for USDP to treat its wastewater to get it down to a level where it can be sent to the city’s wastewater facility, City Administrator Mark Karnowski said.


A delicate balance

The city’s wastewater plant operates on the principal of millions of bacteria digesting sewage aerobically, meaning with oxygen, and working in a kind of delicate balance, according to Karnowski. The bacteria need enough of a supply of sewage to survive and grow, but if too much of certain materials come in, the bacteria can be overwhelmed, Karnowski said.

In fact, Karnowski used the word, “havoc,” to explain a situation where the wastewater plant should ever become overwhelmed, noting that it would take days to recover before it could again treat wastewater.

Among the problems that could result while the plant is not working, he continued, is a heavy sewage odor.

The city’s wastewater plant operators are “always cautious” about what might be getting into the city’s wastewater mains, noting that the local hospital and the various industries could be potential contributors of something harmful for the wastewater processing, Karnowski said.

The key is to know what is coming into the wastewater collection system, Karnowski said.