Compare and understand the most common calcium carbonate scale prediction methods for cooling waters. Learn where and why some methods are inaccurate, and understand how an accurate prediction method can optimize a calcium carbonate scale-control program as well as provide a cost reduction in cooling water treatments.
Is it time to reconsider testing for total bacteria and Legionella in cooling tower water? Two case histories demonstrate how current water-testing methods could be indicating that bacteria control is acceptable and under good control — when the opposite is true.
Microbiological testing, specifically for total bacteria and Legionella bacteria in cooling tower water systems, has been using a methodology that basically has not changed for many years. The recent Legionnaires’ disease outbreaks due to cooling tower water systems has prompted a closer look at the methodology to determine if there is a need to consider a change that would be more representative of the true microbiological levels in these systems.
A common saying in the water treatment industry is that cooling tower manufacturers do not know (or care) about water treatment. Likewise, the cooling tower manufacturer says he knows how to cool water and does not address water treatment.
"Should filters be used on cooling water systems?" is a question I am
often asked. So what do I say? Well, it depends on a number of
considerations, but my first response is absolutely an unqualified
"Yes." Filters are a cost-effective investment. Filters remove
suspended solids from the cooling water and thus reduce many problems.
So, what are these considerations?
"Do all closed chilled water systems need water treatment?" is a
question I have been asked numerous times. Why is it asked? Well, I
know of persons who have been in charge of closed chilled water systems
that do not use any water treatment chemicals whatsoever -- and operate
An oxidizing microbiocide is as any chemical that is an oxidizing
agent. They are chemicals that kill and destroy not only the
microorganism but also the nutrients found in cooling water. Their
action is essentially "wet oxidation" or "burning" under water. No
microbiological organism is immune to this action -- provided that the
oxidizing biocide can reach the microorganisms.
Cooling water microbiological control is important all year long -- and
even more important during the warm days of summer. This is not only
due to warmer water temperatures but also due to more nutrients and
microbiological organisms entering the cooling tower system from the
What is MIC? It stands for microbiologically influenced corrosion --
yes, corrosion in water systems due to microbiological organisms. These
microbes do not "eat" metals such as mild steel, stainless steel,
copper alloys or galvanized steels. Rather, they produce byproducts
that are corrosive to these metals.
Check out the October 15, 2020 edition of Process Cooling: Precooling field produce for prolonged shelf life and quality, ammonia liquid chillers for accommodating plant growth, creating energy-efficient chiller systems, news, products and more!