Iron Bacteria Testing

[dalepuskas]

I'm working with a water district that gets its water from a series of wells, one of the new wells (2yrs old) has been tested with iron reducing bacteria between 500-9,000+ CFU/mL (note most results are reported in CFU/100 mL) for the past year (wasn't tested prior because it wasn't being used). But the pump has been pulled and none of the pipe nor the pump screen has any indication of biofilm growth; no dicoloration, no slimy feel, metal has the usual sheen.

Upon closer inspection of the results from the lab, I found out they were using a B.A.R.T. test (

http://www.lamotte.com/pages/domwat/bart.html),

as compared to the usual agar method, and using the manufactures lag time indication for determining the CFU/mL.

My question is if anyone has had any experience with the B.A.R.T. test method?

 

[kr1114]

Hi there,

In my last year at university I was taught by the guy who invented the BART test - Dr. D. Roy Cullimore. I was fairly impressed with how it worked and in fact I did my final year project using BART tests. Then when I graduated and got into consulting I used this test at one of my sites to test for IRBs (iron reducing/related bacteria), SRBs (sulfur reducing bacteria), HAB (heterotrophic aerobic bacteria) and a whole host of other bacteria. When I used it in consulting I put the BART tubes in what was basically a turbidty meter which was hooked up to a computer where the computer was taking readings at set intervals and at the end, a graph was produced that related the admission of light through the substance to colony forming units. If you don't use a computer you will bascially have to babysit the tubes day and night for the first few days and record what you see.

Summary: I found this test to be useful for prescene/absence of certain bacteria which helped me to make decisions how to migiate the problem. It is a fast and (I think) reliable test for a fairly low cost. I don't know where their technology is at now but I attached their website if wanted to look at it.

http://www.dbi.ca/

 

[dalepuskas]

Hmm I guess I should clarify; I don't doubt its use as a presence/absence test, but I doubt it is appropriate to determine actual colony counts based on lag time until sign of growth.

When you did research with the BART test did you use it to determine estimated colony counts based on signifer lag time? The lab that our samples have been sent to have been using the BART test to determine colony counts based on the lag time and DBI's recommendations to determine colony counts.

 

[kr1114]

your assumption is correct. you won't be able to determine actual colony counts with a BART tester, rather you will get a ballpark figure of how many cfu's there are. To get actual colony counts, the old plate counting method is still the best.

Remember that one of the most important signifers with the BART tests is the reaction time. For example if the test was done over 10 days (I am just using 10 days as an example) and if the number of cfu's increased slowly over the 10 days then you do no have aggressive IRBs in the well water (which is probably why you did not notice any visible growth on the pump or well screen) however, if the reaction time was very short (say a couple of hours or 1 day at the maximum) then you have an aggressive colony of IRBs and you would definitely notice bio-film forming on the pump and screen not to mention the pump would be starting to rust.

When I did my test on a groundwell I too had IRBs in my water sample and I did not notice any visible indicators (i.e. staining, slime, etc...) because my reaction time was over several days. Although there were IRBs in my water samples they were not an aggressive enough colony to do any real harm.

I hope this helps....

 

[dalepuskas]

This helps a lot. I am also in contact with someone else through various contacts that has also worked with Dr. Cullimore, so the more anecdotal info I receive the better I feel going to the testing lab with my concerns.