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Legionnaires' Bacteria Reemerges In Previously Disinfected Cooling Towers
schwit1 writes with the New York Times' unsettling report that 15 water-cooling towers in the Bronx that this week tested positive for Legionnaires' disease had been disinfected less than two months ago.
From the NYT: After an outbreak of the disease killed 12 people in July and August in the South Bronx, the city required every building with cooling towers, a common source of the Legionella bacteria that cause the disease, to be cleaned within two weeks. ... [The] city found this week that bacteria had regrown in at least 15 towers that had been cleaned recently in the Morris Park section of the Bronx. The testing occurred after a fresh outbreak in that area that has killed one person and sickened at least 12, and spurred an order from health officials for the towers to be disinfected again.
But, we forgot about lazy, cheap people.
Yes, chlorine or hydrogen peroxidation would solve this, but require some method to maintain the antiseptic aspect.
Copper sheeting might shed enough Cu ions for many years, but would ne replacing as it eroded away.
Newly installed cooling towers deal with this, as this search shows.
https://www.google.ca/search?q...
You said the key word there: Biofilms
Odds are that they never actually (or fully) disinfected the system. A lot of bacteria remained, sheltered by biofilm, and disinfectants are proven to be ineffective against biofilm. After they "cleaned" it and checked the bacteria levels, it was just a matter of time before the biofilm naturally continued releasing the bacteria...