Friday, September 25, 2015

Nualgi in Lagoon STPs and dams in Queensland, Australia

An Overview of Trials Using Nualgi in Lagoon STPs and dams in Queensland, Australia

This blog post is somewhat more technical than some of the other posts I have done to date. The reason for this is that I am presenting actual data! Yes! The numbers are in and I have graphs, relationships and hypotheses to offer. So if you are interested in the more analytical side of things then I hope you enjoy this post. As we are moving towards summer here in Australia things are warming up so the cyanobacteria are getting more active and the use of Nualgi in these tests is going to get properly tested to see how good it is. I hope you enjoy the report and as always, feel free to contact me if you want to know more.
Nualgi is a nano-silica nutrient mixture that has all the micronutrients required for growth of diatom microalgae adsorbed into the amorphous nano-silica structure. As only diatoms have a requirement to take up silica, they are the only algae that benefit from the micro-nutrient boost. This means that the diatoms successfully out-compete the other algae for nutrients, and reduce blue-green algae growth in a natural way. The process is non-toxic and offers an added benefit in that bacterial activity is enhanced due to the increased dissolved oxygen content from the diatom bloom. This increase in dissolved oxygen and bacterial activity will assist in bringing down the biochemical oxygen demand (BOD) in the wastewater. 


The three trials presented here are each slightly different in regard to the conditions of the STP or the water being treated.  Trials 1 and 2 have both shown a strong change in the percentage of the BGA that make up the Total Cell count.  A similar pattern may slowly be emerging in Trial 3 which has a lower N concentration.
The Total Cell Counts in all trials have been seen to reduce markedly from the starting values.  Trial 2 has shown some recovery of non BGA algae, although this stage may be transitory as the lagoon continues to settle toward having a higher DO and lower BGA population.
Because of the increased activity of diatoms, especially benthic diatoms, induced by the addition of Nualgi there have been several positive changes to the water quality.  In Trial 3, a reduction in the pH and a qualitative assessment that the invertebrate populations in the water have increased suggest that the water is progressively returning to a more stable environment in which algae other than BGAs may proliferate and the nutrients will shift from being retained in algal cycles and may now move up the food chain through the invertebrates and into higher animals such as fish, eels and birds.
Longer trials are needed to assess the long term use of Nualgi in managing nutrients and controlling Blue Green Algae growth, but these three trials are strongly indicative that the use of Nualgi is a simple and effective pathway to achieve this outcome.

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