Bioreactors

This reactor is a continuous unit treating an aqueous waste stream from a chemical plant. The treated harmless effluent is discharged into a river or the sea. An example of effluent treatment is the water industry where dirty water from households is cleaned up before discharge.

In this particular example, a contaminant in the waste stream is removed by oxidising it with oxygen on the surface of catalyst particles. The oxygen is fed as a gas into a continuous reactor fitted with a ‘draft tube’. The oxygen bubbles up the draft tube and the low density of the fluid (gas plus water) in the tube causes the contents and catalyst particles to circulate and mix. The better the mixing, the more oxygen and contaminants can reach the catalyst surface, increasing the reaction rates and thus reducing the contaminants in the stream leaving the reactor.

The user can adjust the oxygen feed rate and the catalyst loading and challenge for this game is to optimise the use of oxygen and catalyst, ie not to spend too much money or waste too many resources, but still ensure the effluent is safe to discharge.

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