|Photobiorector Research At Bedford School|
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Three members of Bedford School (James Gardner James Backhouse and
Richard Claber) have begun some research into the factors
affecting carbon dioxide absorption by bacteria. The hope of
Profesor Hall, who is supporting us, is that if our research is
succesful and we are able to carry it out in a school rather than
a university experiment, other schools may also be able to take
up similar research projects.
We feel that high levels of carbon dioxide in the atmosphere
will continue to be a problem to the environment into the
foreseeable future. The photobioreactor may well offer a
practical way to reduce carbon dioxide emissions from power
stations and other industries producing carbon dioxide in an
environmentally friendly and efficient way. The bacteria
cultivated in the bioreactor can even be used as a food stuff for
The aim of our investigation is to research into the optimum
design of a tubular photobioreactor that is capable of removing
carbon dioxide from a waste gas outlet. The two basic goals we
have are to produce a bioreactor that removes maximum possible
amounts of carbon dioxide, and also to make the design we choose
as efficient as possible. We are building on research already
conducted by Professor D.O. Hall of King's College, London, and
plan to improve on his design.
The general construction of the photobioreactor, as of present (it is still subject to alterations), is as follows: It is made of 90 metre long transparent PVC tubing coiled up into a double helix around 5 wooden dowels. Within this tubing is a culture medium with the photosynthetic bacteria Spirulina Platensis. 10 fluorescent lamps on the inside of the coil provide light for photosynthesis.
At the top of the reactor there is an air pump, this pumps medium into the degasser which in turn circulates the medium and bacteria around the system. At the bottom of the bioreactor, carbon dioxide enters the tubing. The carbon dioxide dissolves into the medium where it is taken up by the bacteria for fixation. A degasser at the top of the system allows the gas to escape, whilst the liquid returns back down the tubing into a water bath set at the bacteria's optimum temperature. Due to the nature of a bacteria culture, the bioreactor can only run for several days at a time.
We now plan to alter certain variables in order to attain maximum carbon dioxide removal. This will include input gas flow rate and carbon dioxide concentration, general apparatus set-up and also the basic shape of the bioreactor. By altering the available variables, we hope to find the highest possible efficiency that the bioreactor is capable of producing. However, we have also allowed for the possibility of making some more major changes to the shape or design of the bioreactor, if this is likely to improve the performance. One idea we have already had is to set up a conical photobioreactor of similar design capable of utilising sunlight.
If our work was actually to be used on a commercial basis, it should have to be as cheap as possible, and for this reason we are going to try and calculate the efficiency of the bioreactor. This will involve determining the energy used up in the bulbs and pumps compared to the amount of carbon absorbed. Change in dry biomass weight will serve as a measurement for carbon uptake.
At present, there is no necessary finishing deadline, and we plan to continue until we have exhausted the possible ideas, unless some other reason forces us to stop. Due to the limited available time each week our team will have to meet, it is likely that the project will continue into the next school year, with the final possible finishing time of Easter 1999 (owing to final exams).
Below is a rough summary of our costs:
Main Photobioreactor: £77.20
We have not applied for financial assistance from any other source other than the Royal Society - Esso Partneship Grants scheme at present. However, certain equipment is already available form our school free of charge including a data-logging computer. Some of the PVC tubing has been donated by Professor Hall, along with the bacteria.
The research project is intended to be an opportunity for us to investigate something that interests us under our own initiative, with the teacher present merely in a supervisory role. The project will allow us to explore areas of science outside the normal school syllabus.
Two members of the team (James Backhouse and Richard Claber) study Biology, Chemistry and Maths whilst James Gardner studies Physics Chemistry Maths and Furthur Maths. This means that all of us can learn more about areas of science which we are not normally involved in.
The project will be conducted in the school, and we have been allocated a room dedicated to the investigation.
Welcome to the Photobioreactor Research Web Pages
page written by James Gardner e-mail jamesgardner @ unforgettable. com