Hi Jerome, I can email you ...

Hi Jerome, I can email you case studies here in Australia. My email is andrew@waterandoilsolutions.com.au

As a tertiary treatment, we were able to lower BOD and COD to within limits over a period of 30 days. What surprised us was the area of effect of the nanobubbles. We had read in research that once they stabilize between 300nm to 1 micron in diameter, they can actually remain suspended in the water for several days. We believe this to be the case with the trial at this particular STP. There is no physical way to measure the presence of nanobubbles in such a large water mass. However, we were able to note fish appearing at the outlet of the 1st tertiary pond after 20 days. This is 100m away from the aerator. Initially, we specified 2 aerators using conventional conservative calculations but due to budgetary constraints, only 1 aerator was used. The effect of the micro and nanobubbles were a surprise because we did not expect to reduce BOD and COD that much.

Water quality monitoring of this site can be seen at http://www.mpsc.nsw.gov.au/index.php/home/waste/epa-monitoring

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Note that the aerator was commissioned on March 31st 2016. It was taken out in late October for servicing and put back in mid-November 2016. Sampling this year should give a better indicator of performance. The STP operators are planning to replace the existing three 75kW aspirator type aerators with three micro and nano bubble generators each 6kW in size. This is a reduction of 92%. 

SOTR results from University of Southern Queensland show an estimated SOTR of 5kg O2 per hour and SAE of 3.15 O2 per kWH. This does not account for the dissolved oxygen in the form of nanobubbles, we have not found a solution yet in research to measure these accurately. We only know from the decrease in BOD and COD that there is possible a theoretical bank of stored oxygen in the form of nanobubbles. A visual way to detect the presence of nanobubbles is by green laser irradiation which we have confirmed.

Another interesting test we have done is 100% saturation of ozone in water in the form of nanobubbles. The water turns a pale pink color.

In terms of oxidation capabilities, we know that the oxidation potential of water can be raised up to 200 mV through hydrodynamic cavitation in a static mixer. As the nanobubbles are generated and collapse they decrease the zeta potential of the water, thus increasing coagulation and flocculation reactions and increasing oxidation potential. This has been tested in swimming pools with water temperatures typically between 30 and 35 degrees C.

We are currently testing nanobubble suspension and chemistry in salt water, this is of great interest to the prawn industry here in Australia.

We have also successfully used micro and nanobubble generation in pre-treatment of drinking water to oxidize iron, manganese, and breakdown 91 agricultural chemicals in river water through a micro and nanobubble generator in an aeration tank and a series of static mixers.

I am happy to answer any questions on micro and nanobubble research and application.

My email is andrew@waterandoilsolutions.com.au