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Water Treatment & Distribution - Industry Primer

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Industry Primer   |   Products   |   Calculations   |   Test Program Setup   |   Additional Resources

For a quick introduction of LuminUltra's capabilities in this market, go here.

Background

Water is mankind’s most valuable resource.  If it is not closely monitored, it can also be a breeding ground for microorganisms.  It is therefore the responsibility of municipalities and industrial water users to ensure clean water is available to minimize public risk.

In addition to health concerns, water quality management has significant implications with infrastructure management. Storage tanks, underground pipelines, and building water lines are all effected by microbial growth.  Microorganisms tend to form thick deposit layers known as biofilms on tank and pipe surfaces to establish a favourable ecosystem for growth and for protection from disinfection.  This can also lead to microbially-induced corrosion, eventually resulting in line breaks and premature equipment failure.

Additional Information:

The QGA method is similar in design to ASTM Standard D4012 for the measurement of ATP in water.  The full standard can be obtained here: http://www.astm.org/Standards/D4012.htm.

How can ATP Monitoring Help?

In water distribution systems, the bulk of the microorganisms is usually associated with the surfaces (sessile microorganisms) rather than those that are free-floating in the water (planktonic). To assess microbial content of fouled surfaces, biofilm collection devices are often installed within the system on which microorganisms grow and then measure the growth on these devices. LuminUltra's ATP technology is superior for measuring this type of sample because of the superior ATP extraction efficiency, sampling accuracy, and the ability to overcome interferences in the form of corrosion products and other non-microbial build-ups.

The use of QGA and DSA provide water treatment professionals with the ability to:

  • Assess raw/make-up water quality, which can also assist in estimating loading on the disinfection process.
  • Obtain a real-time estimation of overall disinfection efficacy.
  • Assess downstream locations for regrowth.
  • Quantify microbial build-up on surfaces.
  • Troubleshoot contamination via line breaks (trace up the line to find the source).
  • Prevent premature equipment failure by prevention of microbially-induced corrosion (MIC) and line plugging.
  • Supplement HACCP programs for preventative control of Legionella (http://www.legionella.org/).

While a combination of bulk water and biofilm analyses provides the best basis for microbial growth control, if surface analyses are not possible, bulk water monitoring on its own can be effective. If the planktonic population of the distribution water is increasing, the biocide control program is not effective. This information can therefore be used as a starting point for water quality management.

Types of Disinefction

  • Chlorine – Due to its relatively low cost, good effectiveness, and widespread availability, chlorine treatment is the most commonly used disinfectant for water treatment.  It is able to kill most microbial species, although it has been known to struggle with cyst-forming species (e.g. cryptosporidium).  It is also pH-dependent, with disinfection being less effective at pH values above 7.5.

Additional information:

Chlorine: http://en.wikipedia.org/wiki/Chlorine
Chlorination: http://en.wikipedia.org/wiki/Chlorination

  • Chloramine – While not quite as aggressive as chlorine, chloramine is often favoured because of its longer-lasting residual and also because it has a lower tendency to form disinfection by-products such as Trihalomethanes (THM) and Haloacetic Acids (HAA).  The main drawback to chloramine is that it contains ammonia in addition to chlorine, which serves as a food source for nitrifying bacteria.

Additional information: http://en.wikipedia.org/wiki/Chloramine

  • Chlorine Dioxide – While the most common use for ClO2 in the past has been for pulp bleaching, it is becoming more widespread in water treatment due to its ease of use (onsite ClO2 generators) and ability to destroy organics.  It is also more effective than Chlorine at pH values greater than 7, where chlorine on its own is less effective.

Additional information: http://en.wikipedia.org/wiki/Chlorine_dioxide

  • Ozone – While ozone can be a very effective biocide, it does not maintain a residual.  Therefore, additional biocide (e.g. chlorine) must be added downstream of treatment to establish a disinfectant residual prior to delivery to users.

Additional information: http://en.wikipedia.org/wiki/Ozone

  • UltraViolet (UV) – Perhaps the most common non-chemical water treatment, UV de-activates cells rather than destroying them, thereby preventing them from re-producing.  Like ozone, additional treatment is required downstream to establish a disinfectant residual.

Additional Information: http://en.wikipedia.org/wiki/UV_water_disinfection

Unique Situations

  • Biofilm Analyses – In addition to assessing bulk water cleanliness, LuminUltra’s DSA test kit can provide a quantitative measure of sessile build-ups. This can be achieved through three sampling mechanisms: swabbing, scraping and weighing a deposit, and directly testing a biofilm collection device. For more information on this, consult the DSA overview in the Products section of Water Treatment & Distribution.
  • Biologically Active Filters – Since, organic material present in municipal water can be converted to harmful disinfection by-products (e.g. THMs, HAAs) when chlorinated, biologically active filters are becoming more commonly used to reduce organics biologically prior to treatment. This involves passing water through a media filter which supports an indigenous microbial population. ATP monitoring can be used to quantify the microbial population within the filter and also detect the onset of breakthrough at the filter outlet.
  • Distribution System Infiltration - Leaks in water lines once thought to be insignificant with respect to fouling are now understood to be important. Negative pressures regularly occur in pipelines resulting in infiltration, which can be a significant contamination risk. ATP monitoring can be invaluable in these situations to identify the severity of contamination and quickly trace up the line to locate infiltration points.

Regulations

In most jurisdictions, government regulations are put in place to regulate treated water quality as well as that which is delivered to customers.   It is therefore critical to maintain cleanliness at all points in the system to prevent water quality violations.

Additional Information: