Posted by William Vander Plaats on Thu, Jun 03, 2010 @ 01:45 PM
Another recent round of outbreaks of Legionnaires Disease have made the news recently, underscoring the fact that even though we know the cause, prevention is still not always taken very seriously. Like those Legionella cases mentioned back in mid-December, many of these may have been prevented as well. According to the Center for Disease Control, the disease has already caused 538 deaths in the U.S. so far this year, and even more non-lethal cases have been found.
- In Sacramento, a cooling tower that cools and heats California's state capital building has twice tested positive for very low levels of Legionella
- Australia has seen a jump in cases of Legionnaires Disease recently as well. In the Victoria province alone there have already been 34 cases to date -- double the average
- In the United Kingdom, a recent death attributed to Legionella at a hospital and
- Also in the UK, fines charged to a building owner for NOT having a Legionella prevention system for the cooling towers
ASHRAE Guideline 12 outlines ways in which Legionella can be prevented, and a centrifugal separator is a suggested part of the solution. Properly sized and applied, it can prevent the situations in which Legionella can grow.
Legionella In Healthcare Environments
Hospitals and other healthcare environments are particularly vulnerable to Legionella and other bacteria because of the demographics of the patients, including elderly people and those already suffering immune deficiencies. Following proper cooling tower basin cleaning techniques in these facilities is a great step to prevent the growth of Legionella, but also to save water, energy, and reduce other liability risks inside the hospital.
Want to learn more about the special Legionella challenges in hospitals? Or just about preventing Legionella in general?
Visit our special hospital filtration page or download our "Preventing Legionella" brochure !
Posted by William Vander Plaats on Wed, Oct 21, 2009 @ 04:00 PM
Cooling towers for large buildings and plants are often magnets for dirt and other airborne particles. This is especially true if they are located near open fields, airports, or other things that raise the level of airborne debris. Contamination in tower basins can also be caused by large amounts of precipitated minerals from water treatment (calcium carbonate) or non-chemical water treatment.
The accumulation of this dirt and other solids will result in:
- Reduced efficiencies for all the system components
- Increased maintenance costs, since manual cleaning of the basin will be required from time to time
- Increased water usage, since occasional backwashings will be required
- Increased chemical water treatment costs, since the chemicals will not react as efficiently with non-filtered water as they will with FILTERED water. More chemicals will be needed if the water is not filtered.
A very effective method to prevent this accumulation of dirt is twofold: first to
- use strategically placed nozzles under pressure to keep the dirt from settling in one place and direct the dirt toward the inlet of a
- separator or other filtration device such as a sand media filter to remove the dirt and unwanted solids.
A short video showing how this is accomplished using LAKOS products is available on YouTube. Cooling towers can be custom built or purchased from a major manufacturer, and common basin layouts are available for those common sizes.
Deaconess Hospital in Oklahoma City (Case Study AB-209) saved 60 man hours per year AND reduced employee liability and water usage by installing such a system. They kept their heat exchangers and chillers clean and running at maximum efficiency using this system. This also helps in Legionella prevention as well, a special concern for hospitals.
Saint John's Hospital in Indiana (Case Study AB-208) experienced the same results with their system, consisting of a closed loop system and two chillers. Similar results have been found by many other cooling tower owners.
Have you ever tried to clean a cooling tower basin by hand?