April 10 – The white clouds that form and dissipate in a glass of Grand Forks water just after it comes out of the tap can be the most notable feature of the city’s water supply.
It is dissolved oxygen, according to Fred Goetz, who oversees the new $ 150 million Grand Forks water treatment plant, and clouds form when the relatively cold water flowing through the hydraulic system heats up when entering an apartment or home. In addition to the clouds and occasional calls, sometimes irritated, about them, Goetz and other employees of the new plant and its predecessor usually work unnoticed. Goetz hopes to keep things that way.
The new plant has a “hybrid” design, which means that it can filter and clean river water with a relatively new system of membranes or a more conventional system that depends on lime softeners. The water that travels through the membranes ends up with a different pH value than the water treated with lime, which means a different process to make it drinkable. Goetz said that consumers should not know the difference between one process and another when they use city water.
“If they notice that I’m doing something,” he said, “then I’m probably doing my job wrong.”
Factory workers moved into the new building in May, but did not start pumping water into the city’s distribution system until July 17, when Mayor Brandon Bochenski ceremoniously opened a valve in front of a group of city officials and contractors .
The plant is a project “that occurs once in a century,” said Bochenski in his first speech on the state of the city last month, and it was designed to expand as the city grows: water usually enters the west side of the building and is processed through it to the east before being pumped into the homes of Grand Forks. The building was designed to expand to the north and south to accommodate more filtration and treatment equipment.
The factory team works in pairs, testing the water at different points in your system, making sure that the equipment is operating correctly and monitoring the entire factory from a vibrant control room that they have dubbed “the con”. Workers are using almost exclusively the most modern membrane system to treat Grand Forks drinking water and typically pump around 7.5 million gallons of water a day across the city. The most conventional lime system is ready to go into action if the membrane system fails or becomes overloaded.
“We decided to make a hybrid plan so that we can always send wet water to you as a customer,” said Goetz. “We have piloted membranes for five years to make sure they work for us, but … it is something new, and being conservative in North Dakota, we wanted to be sure.”
In addition to its monumental initial cost, the new factory, which is on the western end of the city, costs more to operate than the old one adjacent to the Red River. Goetz and Melanie Parvey, director of the Grand Forks water reservoir, said it is difficult to quantify how much the new plant is more expensive, in part because it has not been in operation for a full fiscal year. Still, Parvey and other city administrators increased their water treatment budget from $ 5 million in 2018, before construction of the new plant begins, to $ 5.5 million in 2021, which will be their first full year in operation.
But, costs aside, the membrane system is more efficient than lime, and the water it produces is considerably cleaner, even though it looks the same to the naked eye. The old water treatment plant, which used exclusively a conventional treatment system, took water measured in about 70 units of nephelometric turbidity – a metric used to measure cleanliness – and cleaned it to around 0.10 “NTU.” The new plant may reduce that number to 0.02 NTU.
The difference between these numbers, like any day-to-day differences in plant operation, should not be noticeable to residents, said Goetz, but it is meant to be a protection against “emerging contaminants” in drinking water in the United States, such as as fertilizers. , pesticides, medicines that people throw into their drains, and the polyfluoroalkyl substances – “PFAs” or “chemicals forever” – that have become a problem in other Midwestern cities, such as Bemidji, Minnesota, where water gushes close by from an airport location have been contaminated by fire-fighting foam containing PFAs.
Sulphates, for example, can flow from the Devils Lake basin to the Red River south of Fargo, and then north in the drinking water of the Big Cities. Ingested in high enough amounts, these sulfates can be a laxative. Conventional lime filtration cannot capture them, but the plant’s membrane system can, said Goetz.
The new plant can also filter PFAs, but in a 2018 test, they have not yet appeared in the Grand Forks water supply. The city is ready to test them again in the coming years, depending on when the federal government updates its drinking water regulations.
“Yes, it is more expensive to treat the water, but now we are protected from future contaminants,” said Goetz. “And the goal when we started this installation was for you, as Joe Público in general, not to be able to notice the difference.”