We are often asked to review, audit, improve upon, or otherwise comment on Water Management Plans (WMP’s) consisting of no more than a few pages of boilerplate text which, in reality, are actually NOT Water Management ‘Plans’ at all.  Rather, they are simply Legionella control policies.

So, what’s the difference between a “Policy” and a “Plan”?

Policy (always a noun):  a course, principles, rules, guidelines, etc., proposed or formulated by an organization, government, business, or individual, typically published or promulgated throughout the organization, in order to direct organizational behavior towards (or away from) a particular goal, objective, or condition. 

The phrase “Part Per Million” is a term we use to describe very small amounts of something in a much larger amount of something else. Here are some examples of one part of something in a million parts:

On a recent episode of the Public Broadcasting Systems’ Frontline “Flint’s Deadly Water,” investigative reporters looked deeply at the city of Flint from 2014 to now in hopes of identifying the true causes of the water crisis and the cause of the many deaths. As an outsider, we immediately associate Flint with a lead crisis, which undoubtedly remains an issue. However, Frontline finally dives deeper and states that Legionnaires Disease is the true public health crisis that happened in Flint. Below is a summary of the research they did and their findings.

Thermal energy storage (TES) systems are cooling systems that can use ice banks, brine systems, or chilled water storage tanks to capture BTUs for the purpose of removing a heat load at another point in time. In practice, the chillers for the TES operate outside peak electrical load hours and store the BTUs in the preferred form for use during peak electrical load hours. This practice reduces strain on the electrical grid and provides both cost and energy savings for the owner.

Cooling towers are a critical component in many water systems, providing comfort or process cooling across a broad spectrum of technologies and applications. Cooling towers vary greatly in design and footprint, but all have the main goal: to provide removal of waste heat from processes or building systems. Control parameters are critical to maintaining any cooling system to improve water and energy efficiency, maximize equipment life expectancy, reduce hazards, and minimize downtime.

We detected the presence of Legionella in one or more of our building water systems….. Now what do we do? This is probably the second most commonly asked question, surpassed only by:  “Do I have to test my water systems for Legionella?”  Often the question is posed this way:

“We recently performed Legionella testing on our building water systems and found one or more positive sample results.  What should we do about it?”

Each day people all over the world are exposed to ice. Whether it be from their refrigerator ice machine, their favorite restaurant, during their hospital stay, or on an airplane, people sip on their ice cold beverages or suck on ice chips unaware of the microorganisms that could be sitting dormant within the ice.

The simple answer is no (not directly), and here’s why:  There is no known safe level of Legionella in a building water system.  Therefore, even a non-detect sample result is not necessarily “safe.” The reason why is because the life cycle of this organism, coupled with the stresses put on it via temperature, disinfectants, etc. found within building water systems, may cause it to enter a viable but non-culturable (VBNC) state. 

Chlorine and bromine based biocides are widely used for microbiological control in cooling tower systems. These halogen compounds form strong oxidizing agents in water, which is how they kill bacteria and other microorganisms. Routine testing is important to confirm effective halogen residuals are maintained. Low residuals can result in poor microbiological control. High residuals can cause corrosion and destroy inhibitors.

The source(s) of water supplied to cooling towers, boilers, and processes may vary greatly daily or even hourly.  The impact this has on water systems must be closely monitored to avoid scale, deposits, corrosion, inefficient water usage, and other negative impacts on operational costs.