Tech Talk 25
What is their size? There are thousands of strains and two major groups. Heterotrophs use organic carbon (as we do). They are elongated, often rod-shaped bacteria, typically .2 µ (microns) wide and 4-6 µ long. Autotrophs use inorganic carbon (carbonate or carbon dioxide) as plants do. They are cocci-shaped (round to oval) bacteria, typically .2–.4 µ in diameter.
What do they do? Like all other living things, they have a biological directive to eat and reproduce. They must compete with each other and with predators. Each strain does only one job, so it takes a coordinated team of strains to purify water, for example.
What do they eat? An individual strain may digest a specific type of fat, certain proteins, carbohydrates, cellulose or hydrocarbons. Together the right team can eat sludge, animal wastes, etc.
How fast do they grow? A population of heterotrophic bacteria can double every 20 minutes. Nitrobacter can double every 8 hours. This rapid reproduction (with mutations) quickly evolves new strains.
Where can you buy them? From Pentair Aquatic Eco-Systems, Proline liquid and bacteria in a bag.
Do they move around? Some bacteria form floc, the slippery material one feels on a tank wall. Although many involved in water purification may get trapped in the floc they typically flow through the system. The bacteria on a biofilter are immobile, and water movement is essential to insure that food is brought into contact with them.
Where do they come from? Bacteria can live in most places, but all strains are not everywhere all the time. Water purification cannot be optimized if all the required strains are not present. Bioaugmentation with Proline liquid and bacteria in a bag encourages the presence of the balanced team. If a proper environment exists, they will multiply.
How are they eliminated? Freezing can kill over 99 percent of some strains, such as Nitrosomonas and Nitrobacter. Spore-forming bacteria are less affected, at least the spores survive. UV light, disinfectants, heat, acids, bacteriacides and oxidizers (ozone, chlorine, hydrogen peroxide and potassium permanganate) will also kill them.
What is the relation between light and bacteria? Light is not only unnecessary for the growth of beneficial bacteria that improve water quality, but also will inhibit the growth of nutrifiers, particularly Nitrobacter. Biological filters should be kept in the dark. Ultraviolet light is used to kill bacteria. The toxicity of the uv light is a function of the wavelength, intensity and exposure duration.
Assistance on this Tech Talk was provided by IET, Inc.