|
Special Pathogens Laboratory provides water treaters with microbiologically influenced corrision (MIC) testing. In addition to Legionella and other waterborne pathogens, SPL can identify nuisiance bacteria that create slime and corrosion in industry water systems, cooling towers and boilers.
- Bacteria in the genera Serratia, Chromobacterium, Janthinobacterium
- Produces copious amounts of slime without metabolizing iron
- First symptom is increased turbidity followed by changes in taste, odor or color
- Generates thickest slime formations under aerobic conditions
- Under harsh environmental conditions slime layers get thicker
- Can cause serious engineering problems
- Reduces hydraulic or thermal conductivity and water quality
- Determine the potential for exposure within high risk areas to waterborne pathogens such as multi-drug resistant strains of Pseudomonas, Stenotrophomonas and Acinetobacter
Nitrifying Bacteria
- Bacteria in the genera Nitrosococcus, Nitrosomonas, and Nitrobacter
- Bacteria recycle organic nitrogenous materials from ammonia to nitrates
- Aggressive nitrifiers produce high concentrations of nitrates
- Aggressive nitrifying bacteria in water may indicate stages of aerobic degradation of nitrogen-rich organic matter
- Can indicate water may have been polluted by nitrogen-rich organics from compromised septic tanks, sewage systems, iindustrial and hazardous waste sites
- Potential health risk, particularly to infants who haven’t developed tolerance to nitrates
- A group of anaerobic bacteria that generate hydrogen sulfide (H2S) belonging to the genera Desulfobacterium, Desulfobacter, and Desulfovibrio
- Difficult to detect: anaerobic and grows deep within biofilms
- Sulfate reducing bacteria may not be present in free-flowing water over the site of the fouling
- Causes significant problems in water ranging from “rotten egg” odors to blackening equipment, slime formations, and initiates corrosive processes
Acid Producing Bacteria
- Acid producing activity is a result of a community, or consortia, of bacteria rather than one single species
- The acid producing bacteria cause corrosion due to their fermentative activities, mainly in the biofilms, to drop into the acid pH range
- The acids are produced under very reductive (oxygen-free) environments
- Acid-driven corrosion can cause metals to dissolve and concrete structures to lose integrity
- Examples include: Gallionella, Crenothrix, Sphaerotilus, Siderocapsa, and Thiobacillus ferroxidans
- Difficult to enumerate: subdivided into several groupings (e.g., iron-oxidizing and iron-reducing bacteria)
- Oxidize iron producing thick slime
- Taste and odor problems and “red water” are common symptoms
- Function under different reduction-oxidation (redox)
conditions and use a variety of substrates for growth
|
|
