(Updated 04 April, 2017) In our undersea station one of the ways to absorb Carbon dioxide from the air and to produce oxygen instead might be beside classic scrubbers the Biocoil reactor that was first introduced by a science class of Cascade High School in the US. It looks like a quiet simple system based on Chlorella algae and it was used in Lloyd Godson’s ‘BioSub’ project in 2007.
The Biocoil and BioSUB Projects on ABC’s Behind The News (BTN):
Given an excerpt from the homepage of the Cascade High School Idaho, USA:
‘The Biocoil was a science project first introduced to Cascade by a group of four girls who called themselves the sewage sisters. The biocoil has been running at the High School since 1993. It is a photosynthetic bioreactor, a sustained system that undergoes photosynthesis and uses nutrients, and has a very basic design plan: a tank, a pump, clear vinyl tubing, a light source, and chlorella algae with water. The clear vinyl tubing is normally wound around in a “coil’ because this makes the space that it fills up as compact as possible. The algae and water are pushed through the tubing by the pump and then splashed into the tank, where the oxygen is released and the CO2 is scrubbed. Lloyd will use our system to provide him the oxygen that he needs. ‘
A more detailed report named ‘In-Home Photosynthetic Bioreactor – 1997-98‘ is available on the homepage of Cascade High School.
An article from the magazine Illumin describes the system as follows:
‘Of all the engineering innovations present aboard the BioSUB, the specially-designed Biocoil is the most significant. When researching different air supply systems for the BioSUB Project, Godson contacted Cascade High School in Idaho, where the school’s advanced biology students had spent over a decade researching the properties of the chlorella algae and constructing Biocoils. Chlorella possesses a high photosynthetic efficiency and only requires carbon dioxide, water, light, and a small amount of minerals to rapidly produce energy. Essentially, a Biocoil is a photosynthetic bioreactor that consists of a series of coiled, plastic tubing filled with water and chlorella. The design of the Biocoil maximizes the amount of light available to the chlorella to assist their rate of photosynthesis. In Godson’s case, the carbon dioxide required for photosynthesis was provided by his own respiration, and his urine was recycled to provide the nutrients also required for the process. In this way, Godson and the Biocoil were able to interact in a self-sufficient “human-plant symbiosis”.’ (Source: http://illumin.usc.edu/article.php?articleID=178)
Results of the BioCoil in 2007
So, did the Biocoil reactor worked as desired? The BioSub webpage says: ‘However, the humidity was not at all as threatening as the constantly rising CO2 levels in the air. Although he used algae in a bioreactor to lower the amount of carbon dioxide in the air, the CO2 level rose continuously. The result: Lloyd slept more often, his blood pressure rose to unexpectedly high levels and towards the end he was psychologically at breaking point. Instead of being exhilarated at living in the depths he was beginning to crack. In the end it was the CO2 level that could no longer be lowered that forced him to abandon his experiment after twelve days.‘ (Source: http://www.lloydgodson.com/biosub.html)
Lloyd Godson said to The Scientist, the BioCoil reactor provided 10 % of the oxygen. Godson’s notes on the amount of oxygen the microalgae produced could help create building systems that generate more oxygen, such as by harvesting algae every day to improve their efficiency.
Though it looks like Biocoil was a failure, the idea deserves to be followed up. 10% of the oxygen (which is maybe a polite way to say, that it did not work at all) is surely not enough. And since there are probably no other potential users beside undersea or space stations, we should not wait until somebody improves the systems. So, why it did not work as expected?:
- Chlorella might be the wrong choice of algae.
- the shape of the tube might have been wrong. Instead of one long thin plastic tube, what about wider glass tanks, allowing more gas to pass the fluid?
- What about increasing the number of Biocoils instead of using one single set?
- Was the lighting ideal? Are there better solutions now compared to 2007?
(Wir haben alle Infos über das Projekt BioSub auf der deutschen Wikipedia zusammengestellt. Hier geht’s zum entsprechenden Artikel)
What do YOU think?