Biofilm and biofilm carriers

We have discussed how the water could be cleaned from the majority of coliform bacteria before it enters the channel, to reduce the risk involved with touching the water as well as the smell. One suggestion was to try and make a sub surface treatment with biofilm carriers before the water is released into the channel. Here follows a short, relatively technical, description of biofilm and biofilm carriers. 

Biofilm is a protecting surface (sometimes called slime) for a cluster of microorganisms, for example bacteria. Biofilm is often associated with sicknes but it is very important in wastewater treatment applications. In order to optimise the surface area of biofilm in a waterbodies, like treatment pools, carriers can be used. The carriers come in various shapes and sizes, all to try and optimize the number of bacteria that can sufficiently treat the water in question. The microorganisms extract and digest organic compounds from the water. Bacteria remove organic matter and microorganisms like protozoa and rotifers maily focus on suspended solids, pathogens and other microorganisms. Water is ultimately clean when there is nothing left for the microorganisms to process and then the biofilm goes away.

Biofilms also naturally occur in waterbodies on ricks, pebbles and on macrophytes growing in the water. It the water becomes stagnant there can even be biofilm on the water surface. Biofilm fits into the ecosystem as food for aquatic invertibrates, which are in turn fed on by fish.