Rough Draft
Common Terms
Total organic carbon (TOC) is the amount of carbon found in water and is used as a non-specific indicator of water quality/contamination.
Total Coliform is a common group of bacteria present all around us, which are usually not dangerous to human health.
E. coli primarily come from the feces of warm blooded animals. The presence of E. coli indicates that the water has potentially been exposed to fecal material and an immediate risk to human health exists.
Chlorine or Chloramine is added to municipal water to reduce the levels of bacterial growth while the water travels through the distribution system. The level of residual chlorine/chloramine is typically sufficient only to maintain a disinfected water supply. Not to rectify contamination issues. Drinking water, like every other substance, contains small amounts of bacteria. Most of these bacteria are generally not harmful.
What are coliform bacteria? Coliform bacteria are common in the environment and are unlikely to cause illness. However, their presence in drinking water indicates that disease-causing organisms (pathogens) could be in the water system. Testing drinking water for all possible pathogens is complex, time-consuming, extremely expensive and usually unnecessary. It is simple to test for E. coli and coliform bacteria. If only coliform bacteria is found in drinking water, the source is probably environmental and fecal contamination is unlikely. It is important to find and resolve the source of the contamination.
What if my water tests positive for coliform bacteria? The cause of the contamination must be determined and steps should be taken to prevent a future recurrence. Common causes include new construction plumbing that was improperly sanitized after start-up, dead legs (areas of non-use) or plumbing systems with low or no flow/velocity, unsanitary operation or maintenance of filtration equipment, infrequent filter change-outs or lack of intermittent sanitization procedures and much more. Water temperature plays an important role in bacterial incidences as shown in the chart below. Water filters should never be installed in a “warm” location without considerable consideration and regularly scheduled sanitization procedures. Installing a water filtration device in an enclosed space with a refrigeration unit is a common mistake that can raise the water temperature well above 90°F which is ideal for bacterial colonization. Water filtration systems should be installed in areas that are kept to reasonably cool temperatures. Correct the problem with repairs, procedural changes and/or improved operation and maintenance practices. When coliform bacteria in drinking water is discovered it is recommend that the customer is notified as soon as possible and an alternate source should be used until corrective actions are completed and confirmed.
What is E.coli? E. Ccoli is a diverse group of bacteria. Most strains of E.coli are harmless, many can make you sick. Common symptoms include diarrhea, urinary tract infections, respiratory illnesses and even pneumonia.
What if my water tests positive for E. coli? E. coli in a water system indicates the possibility of fecal contamination which may pose an immediate health risk to anyone who consumes the water. The water must not be used and corrective actions and shock sanitization must be completed and confirmed prior to the water being allowed for any use. E. coli must not be taken lightly as it poses a serious potential health risk. Continued monitoring should be done and redundant approved sanitization methods should be considered. Common sanitization methods include chlorination with adequate contact time, and Ultra Violet water sterilization. The source of contamination must be determined and corrected and all plumbing equipment that is connected to this supply must be properly sanitized. After disinfection, the system must be retested at least 72 hours after the sanitizing procedure to ensure the process was successful
Sanitizing Pipes & Distribution Systems
New plumbing in commercial and residential buildings should be sanitized to kill bacteria when first put on line or if repairs or service have been performed. Shock chlorination is a common methods for sanitizing pipelines. Chlorine's powerful germicidal action reduces bacteria, molds and algae.
The threat of excessive microbial growth along the interior walls of drinking water distribution pipes is a potential health concern. Bio-fouling is the development of an organic bacterial community that is composed of microorganisms and their secretions. It is present in almost every water distribution system and when uncontrolled may present a threat to public health. The key is control. Intermittent sanitization is needed to reduce colonization.
Bio-films are layers of bacteria that attach to the interior walls of pipes and to one another. These bacterial communities trap nutrients, microbes, and waterborne pathogens and can become an almost impenetrable material. Bio-film growth begins when the plumbing system is new due to the presence of foreign material, dirt, plumbing flux, bacteria from plumbers, and environmentally introduced impurities that occur during construction and installation. Additional contamination can occur during maintenance and repair work.
It is extremely important that when a new pipeline or plumbing system is put in service or repaired, a thorough sanitizing and cleaning of the piping is completed.
Initial sanitizing by shock-chlorination:
¨ Inactivates bacteria
¨ Reduces dirt and debris in the piping system
¨ Helps to prevent against bio-film formation
Shock-chlorination:
1. A dosage of 50 to 200 ppm of free chlorine distributed throughout the piping and fixtures.
2. Confirmation of adequate chlorine residual at the fixtures and all plumbing lines. No dead-legs should be allowed as these will cross contaminate the entire plumbing system.
3. Contact time with the piping must be no less than 12 hours.
4. Confirmation of adequate chlorine residual after 12 hours.
If the chlorine residual is less than 10 ppm after 12 hours, repeat the entire procedure above. If the beginning dose is 50 to 100 ppm and the remaining residual after 12 hours is less than 10 ppm, this indicates the potential for severe bio-fouling or foreign material/contamination of some type is present.
All filter media/cartridges that can’t be sanitized must be replaced and the vessels used for the media should be adequately sanitized. Carbon filtration and other media’s that absorb rather than pass the chlorine residual through the media should be replaced or a proper and accepted sanitizing protocol must be followed.
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