Posted By joe.ami on 29 Sep 2010 11:41 AM
No fix for bacterial iron..... so closed loop is the only fix if you are to stay with geo.

Good Luck,
Joe

In case anyone (besides jon) forgot that geo was the context of the discusion.
I also agree that I will often be the source of contrary opinion when someone pretends expertise.
That the other pros here disagree less often is simply proof that they are more the gentlemen than I.
It is true I am less patient with posers.
J

Thanks everyone for the opinions. We are considering how best to proceed. It sounds like we could attempt to treat the problem for awhile. Part of the frustration is that it seems hard to find anyone who knows enough to help. Most people just want to bleach the well and call it good. Or (as the original post said) install a big iron filter that won't do the job.

Also getting quotes on a closed loop. We are on a shared pond so pond loop seems by far to be the most economical, although I am not sure I like the idea of sticking a big apparatus in the pond where people swim and fish. Although it is presumably no problem at all.

Pretty sure an unsuspecting fisherman with a "digger" style anchor could wreck your hdpe pond loop...what do others think???

Ps, do the math, but with federal tax credit you may be better off replacing your heat pump in conjuction with the loop. New warranty, and the heat pump heat exchanger wouldn't be fouled up either.

Posted By Dafr on 05 Oct 2010 08:04 PM
Pretty sure an unsuspecting fisherman with a "digger" style anchor could wreck your hdpe pond loop...what do others think???

Our pond is pretty small.  No gas engines allowed, so not worried about anchoring.  It's a good point though.  People fish off the bank, and get canoes out for paddling around and that's about it.

Interested bystander here, I've put off installing a geo system (temporarily) until I resolve the iron bacteria question too.  The closed loop option is considerably more expensive and seems to reduce the amount of heat available in peak heating system from a given heat pump.  So, I'm dragging my feet before reaching that conclusion.

Does anyone have experience bleaching the well, or other attemps to remove/reduce the iron bacteria?

Posted By waterpirate on 29 Sep 2010 06:25 AM
It has been my experiance that once bacterialised iron is identified as the culprit it is a death blow for your system. Maintanance intervals will become shorter and shorter untill the frequency is undesireable. The time it takes to go from where you are to system failure are the only variables.
We have tried every solution put forward by the brain trusts and drunk guys at the bar and nothing works. We have redrilled to different aquifers and converted to closed loop as the only solutions.
Eric

All of the things I said above are not theory but real world hurt.  Chlorine in any concentration, acid wash, re-development, surge block with chemicals, mechanical removal, anything else you can think of.  If there are successfull pump and dumps near you/within a mile/ you improve your odds.... but there is no free lunch.  A closed loop is a one time investment in a heat exchanger that should last well past 50 years and 5 geo units if we believe the ten year argument.  I wish I could say the same for a water well.

Eric

Thanks Eric, sounds like you do have the right kind of experience. I am slowly nudging from my hope of sharing open loop standing column w/ domesitc water well to seperate closed loop or DX if not cost prohibitve

Finding the right heat exchanger for a specific job can be daunting. Have you talked to any likely installers in your area? Sometimes they can be the biggest help if you can get them to put away the sales pitch in favor of solid design and education.
Eric

Thanks Eric,

Well, I've talked with 2 installers about iron in the water here but have only recently realized it must be iron bacteria (slime in toilet tank).

Knowing only about having iron they both said open loop should work: as long as you don't oxidize the water the iron should stay in suspension. I don't know what they would say re iron bacteria.

We have a fairly new backwashing iron filter. It's performance declined recently (about 1.5 years old) and I talked with a filter person who thought I probably did have iron bacteria. So, I shocked the filter itsellf with a small amount of chlorine and the water cleaned up for several months.

My well was never shocked when it was drilled and I'm thinking about doing that now to see what happens to the iron, any improvement will help the domestic water quality as well.

Anyway, that's where we stand as of now.

As Eric (waterpirate) indicated many procedures are often employed in an often unsuccessful attempt to eliminate or reduce iron bacteria once established in a well--most commonly due to a declining well yield.

These commonly include superchlorination, mechanical swabbing, continuous chlorination, ultrasonic treatments, acid and base treatment, surfactants, and pasteurization by heating the water to 140F for 30 minutes. None are permanent fixes but a combination employed in the correct order may help reduce concentrations temporarily. Removing it from your plumbing is also difficult and must be done as well One option that can help on a longer-term basis for domestic purposes is continuous chlorination. However, this option is not viable for open loop geothermal due to the quantities of chlorine oxidizer or re-injection of this water in aquifers. Sonic jetting is the most recent to come on the scene and we've had some good results with such but again it is temporary.

-Adam
Hydrogeologist

How much of a factor is the oxygen that iron bacteria receive from the air contacting the well column water? My understanding is no oxygen = no bacteria. Or to put it differently, why does iron bacteria grow so much better in the well and pipes than in the aquifer away from the well?

There is a definate connection between the bacteria and flow rates.  The higher the volume of flow the more prevelant the stuff becomes.  Exposure to 02 is really the issue with ferrous iron being taken out of solution, not bacterialised iron.  All we really have to work with here is effects of treating the symptoms not of treating the illness. 

I recently replaced a comercial open loop system that was failing due to bacterialised iron.  The wells were drilled, water was tested, it was found to be high quality i.e. no water treatment needed for building distribution.  The project proceeded and the return well failed within a month, two months later the supply well was toast, subsequent wells were drilled into confined aquifers where ferrous iron was present, and two weeks later we knew that it would not last, just a stop gap.  Solution was to change to closed loop, put building and irrigation back on unconfined supply well and all works fine.

Eric

Thanks Eric and Adam, Perhaps I have already found the best long term solution for my domestic well, and am steered away from the lure of a less expensive standing column well geo source. For domestic water, my well with iron bacteria, feeding through the Pyrolox filter, cleaned every 2 - 3 months with chlorine bleach seems to work pretty well. I could do a chlorine shock of the plumbing, hot water tank, etc once in a while as well.

Groundwater often has a fair amount of dissolved oxygen anyway depending on organic content, depth in water column, whether diffuse or conduit recharge, pH etc. Something to consider is that because iron bacteria converts ferrous iron to ferric iron and this only releases very little energy--the bacteria must convert a lot of iron. Iron bacteria seem to occur usually where concentrations of ferrous iron approach or exceed 0.3 mg/L-which isn't going to support a lot of iron bacteria in a slow-moving aquifer. Now if you suddenly start pumping the water, there is a lot more ferrous iron available to any bacteria in the vicinity, especially in the well bore or pipe. -Adam

Adam, could you explain the process of sonic jetting???

If the cost difference is enough between open loop and closed loop that I can't justify doing the closed loop, it seems it still might be rational to go open loop and plan for annual coil cleaning, and as mentioned earlier, make it easy to valve the coil to cleaning ports. Bringing this thread full circle back to the original poster...

Adam are you from State College Pa?

Happy are you from Jearsey?

South Jersey