The material is covered with a thick film of bacteria. To establish the biofilm, scientists grow the bacteria in the reactor tube. They feed the bacteria a diet of hydrocarbon components and other nutrients. Once the bacteria have multiplied sufficiently to create a thick film in the tube, researchers can use the tube to treat waste water. The water is pumped into the top of the reactor tube.
Gravity pulls it down through the bacteria-covered packing material.
At the same time, air is pumped in from the bottom in order to keep the bacteria growing and digesting. Tests show that using the biofilm reactor, or bioreactor, is a very efficient way of enabling the bacteria to do their work. Both types of bacteria tested were able to remove the hydrocarbons from the waste water in far less time than it takes to treat the water in a lagoon. As well, the reactor bacteria did a very thorough job. The researchers also tested the biofilm reactor on salty water contaminated with hydrocarbons.