From the City of Greeley:
There’s a feeding frenzy going on in east Greeley and it has nothing to do with cows. Rather, Greeley’s “bugs” are chomping away while keeping the city’s wastewater environmentally sustainable.
These bugs — what our wastewater treatment operators lovingly refer to as the “Nitrifiers” and PAOs — have been happy little workers for decades. But soon, their microscopic lives will change for the better.
Keeping the bugs happy
Let’s face it, cleaning wastewater has never been glamorous, but these bugs might as well have a red carpet to an all-star premiere where they will munch away in the all-you-can-eat line at the buffet. Put simply, the city is working to expand their buffet table. In wastewater terms, the city is building new treatment basins where microorganisms that make up the city’s nitrifying force can eat more alongside a lot more friends.
Removing nutrients to meet new state regulation
A new regulation, also known as “Reg. 85” by the Water Quality Control Division, mandates that municipalities work even harder to reduce the amount of “nutrients” that are put back into bodies of water such as the Poudre River after treatment at the Greeley Wastewater Treatment and Reclamation Facility. There, the waste is cleaned and filtered out, with remaining treated water pumped back downstream of the Poudre River.
The regulation mandates municipalities reduce nitrogen and phosphorous levels in their effluent (treated wastewater). Nutrients — nitrogen and phosphorous — are byproducts of human and animal waste and common fertilizers. Excess nutrients in water creates blooms of algae, which use up the oxygen in the water that marine life need to survive. Too much algae can kill off an entire food chain in bodies of water such as the growing ‘dead zone’ in the Gulf of Mexico.
Creating the right conditions for biology to work
The city’s job is to keep the feeding frenzy going, using biology to keep the algae fuel to a minimum. In the right conditions, monitored 24/7, nitrifiers and PAOs (phosphorous accumulating organisms) feed on the nutrients present in the municipal waste. That leads them through a complex biological process in which the nitrifiers convert ammonia into nitrogen gas, which is released into the atmosphere. PAOs collect phosphorus in the waste and congeals where operators can remove it. That is later applied to agricultural land as fertilizer.
Construction of new basins to meet regulation
To meet the new requirements, the city is undertaking a $35.5 million construction project at the WTRF. Greeley is constructing specialized treatment basins that will upgrade the site’s organic treatment capacity. The city also is rerouting the water flow in the basins, allowing the ability to take a basin off line while keeping the bugs happy and complying with the new state regulations. This is the first phase of scheduled plant improvements through 2036.
What the construction and enhancements do now to remove more nutrients will potentially earn the city extra time before having to implement even stricter nutrient removal guidelines that will come into play in the future.
Treating wastewater is getting more complicated, but Greeley operators are on top of making the entire process more environmentally sustainable so not only the state but Mother Nature can be happy – just like the bugs.