The purpose of the game is to make money by treating effluent to the required discharge specification. The more effluent one treats the more money but treating the effluent to better (lower) than the specification doesn’t earn extra money. Failing to meet the standard incurs a penalty fine.
The effluent is treated by reactions using dissolved oxygen and catalyst particles. One can control the amount of dissolved oxygen by controlling the oxygen flow rate, the bubbles. One can also add more catalyst particles. More oxygen and more particles increase the efficiency of the reaction and thus reduce the concentration of contaminant in the outlet. However increasing the oxygen feed and increasing the catalyst cost money.
Be careful. The effluent flow in and concentration vary randomly during the game. There is also a delay as the system slowly responds to the changes in conditions
A bioreactor is a vessel for carrying out biochemical reactions. These reactions could be used to grow microbial plant or animal cells, to make products such as pharmaceuticals, or for effluent treatment as in the model example.
You can find out more about bioreactors here: