Algae Trial in New Zealand

Hamish Macfarlane has introduced me to a company that he has had involvement with named Aquaflow bionomic corporation out of New Zealand. What these folks have done is to tap municipal sewage settling ponds that are already producing algae for their feedstock.

They do not describe all the details of their process, but it is obvious that their first step has to be to run the algae rich water through a filter press. They are then able to harvest the contained lipids from the concentrated algae. No one is talking about yield which must be quite low since we are dealing with a mix of wild algae at this time.

Since the initial feed stock is sewage, it also suggests that the de-oiled dry mass may be unsuitable for cattle feed. This does beg the question of what to do with the substantial dry mass in any attempt to create a commercial industry.

What is important, is that these sewage settling ponds are nutrient rich and need to be biologically reprocessed before the fluids can be reused in whatever manner. Maximizing algae production while capturing the bio available nutrients is a very good intermediate step that preserves the nutrients.

Separating the algae from the grey water is simple, economic and easy with a rotary filter press, and if that produces a product that can then be used as a feed stock for further processing, we may have an economic basis for doing all this.

This harvesting of an algae feed stock from sewage settling ponds can be maximized and be an important contributor to the bio remediation of the sewage cocktail. The algae will not likely be a collector of toxins that it cannot handle or even break down. This means, that by and large this process separates the sewage feed stock into two separate feed stocks.

Through aeration and stimulation the settled and dissolved components will lose a lot of their reactivity and become usable even as high quality crop dressing. The surplus nutrients will end up been carried away in a living algae biomass that can then be perhaps used in further processing.

So far the New Zealand company has been able to collect the lipid content of a natural blend of wild algae. I suspect that the yield is at best a trivial amount of the total bio mass but will at least establish a threshold. We will discover what percentage of oil is retained regardless of processing energy and input. Anything over that may be deemed as potentially recoverable.

Then the interesting question is whether it is possible to selectively stimulate the growth of superior oil bearing strains, and just as important to keep them in suspension. We know that the most important oil algae species likes to sink to the bottom which is not very good in a sewage settling pond.

A simple fix might be the installation of a secondary pond that is fed by a surface waters only drawn off by a skimming barrier and packing the dissolved nutrients and micro organic particulates. Then the algae can grow out primarily in the secondary pond and be aggressively harvested there with pumps.

In a perfect world, the grey water then exiting the secondary pond would be totally spent with all the nutrients absorbed into the algae byproduct.

This would also allow a stimulation of algae populations to improve oil yields.

The other question is if it will be possible to treat the pressed algae in anyway that could make it fit for cattle feed. There is only so much molasses can do, but if the algae mix can sponge up the unpalatable components during the growing phase, then this becomes a very effective way to produce rich fodder for cattle and the oil yield is not necessarily the most important part of the process.

This is a lot of speculation, but at least someone has a working prototype system to explore the possibilities. We will have to keep watching.

In the meantime others will experiment with a mono culture approach fed by chemical feeds.

I personally like the idea of been able to use a wild algae blend, but must admit that I am not optimistic that economic yields of oil can be achieved that way.

No comments:

Post a Comment