What is the ‘Real Cost’ of the proposed thermal chiller not working at the City Admin building?

Fast Forward to 47:00

Notice Director Cotter talking about how the system is malfunctioning because of the high level of minerals in the water . . . then he says that the water then has to be discharged in the the sanitary sewer (this was going on during the summer and not now).

How does this tie to the capacity of the current water reclamation plant?

Rough estimates from doing engineering research is that if this system is running at full capacity during the summer (pumping cool water) and not simply discharging the warm water back into the well, as intended (but back into the sanitary sewer) it would be approximately discharging 300 gallons a minute, which equates to about 14,000 homes in Sioux Falls a day.

I wonder why we need a new sewer plant?



#1 "Very Stable Genius" on 01.15.19 at 12:52 am

Soon, our town will be known not only for cold storage, but for cold sewage too….

#2 Say What? on 01.15.19 at 7:57 am

Wouldn’t a basic requirement of this installed system be a test of the water used for suitability for the intended use, prior to even considering the design. “High mineral content”, re. hard water…oh, it must have turned hard after installation…yeah…that’s it! It is the Romantix Annex.

#3 D@ily Spin on 01.15.19 at 10:15 am

High mineral content? Should we worry about our drinking water. Why is it that older bigger buildings downtown don’t have this problem? Whose brother-in-law sold this turkey to the not at risk CMAR.

#4 Blasphemo on 01.15.19 at 6:15 pm

“Say What”: Your observation is SPOT ON. I wondered the same thing: would it not be prudent to perhaps drill a test well at the site first? Like, HVAC engineers wouldn’t understand in advance that water orifices/nozzles/atomizers/sprayers in a thermal chiller system like this, are susceptible to plugging by water with heavy mineral content??!!!

#5 WellDigger on 01.16.19 at 8:14 pm

Why would it be required to drill a test well first? The City owns several wells not very far from that site and the geology is well known. In fact I suspect that looking at the City water department web pages one would get a good idea just what the water minerals would be. I would be surprised if calls to well drillers would not have gotten a very good estimate of expected results. The engineering parameters of these systems are also well known. Presumably there were no nozzles in a hard water system and they used water to water heat exchanges. In my experience mineralization of these kinds of systems are dramatically amplified when the well screens and heat exchangers are undersized. The temperature and pressure changes which are amplified by undersizing cause the solids to flocculate and also deposit on metal surfaces. A well pumping at that rate would also be expected to depress water tables in a large circular area so a reinjection well would need to consider what level of recycling was appropriate to avoid heating the groundwater near the intake well. Most businesses would not throw the system out without an analysis by an outsider of precisely what would be needed to fix the system. It sounded like the City was saying that the “construction manager at risk” system was setup by the City such that as long as the contractor and engineer blamed the other party the City would be left with no recourse but to eat the cost.

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