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High DO in Lagoons
Kit Roush
Posted: Thursday, January 19, 2012 3:32 PM
Joined: 4/20/2010
Posts: 1


I have not seen of anything like this before.  One of my company's clients in New Mexico runs their four cell lagoon in series: aerated pond --> aerated pond --> facultative pond --> facultative pond.  They have been getting DO results of 16.0 mg/L from the facultative ponds.  This is using a DO meter AND a Winkler test kit side by side.  The two test methods are giving the same results.  The DO in their aerated ponds is running around 3-4 mg/L.  We have asked them run the test again early in the morning and again late in the day to see if the DO is depleted over night.  Has anyone seen algae produce this kind of super saturation?
goldenroshan
Posted: Wednesday, February 1, 2012 8:58 PM
Joined: 2/1/2012
Posts: 1


Hi Kit,

  I think it is just normal to have those values of DO. We are getting the same values here in our lagoon ponds in the Philippines. Especially, during sunny days. You can refer to the Standard Methods for the Examination of Wastewater, p.5-5. It mentioned that supersaturation is normal for cold waters and photosynthetic waters.

I hope this would help


JDBonner
Posted: Tuesday, June 19, 2012 12:38 PM
Joined: 6/19/2012
Posts: 1


Hi,

 

Typically when I have seen supersaturated DO readings in a facultative lagoon it has been during times of low rainfall and high temperatures.  What you are probably seeing is lagoon turnover.  I can't remember the exact process but it is due to the carbon dioxide being stripped off the upper layer of water.  I would assume they took the DO reading sometime around midday.  Another way to test this is to check the pH when you get a high DO reading.  If the pH is also high this is a typical sign of turnover.  Also this is a natural occurance.  The only thing I know is to change the time of sample collection to early morning to late evening.