Slashdot Mirror
Wrong Chemical Dumped Into Olympic Pools Made Them Green (arstechnica.com)
Z00L00K writes: [Ars Technica reports:] "After a week of trying to part with green tides in two outdoor swimming pools, Olympic officials over the weekend wrung out a fresh mea culpa and yet another explanation -- neither of which were comforting. According to officials, a local pool-maintenance worker mistakenly added 160 liters of hydrogen peroxide to the waters on August 5, which partially neutralized the chlorine used for disinfection. With chlorine disarmed, the officials said that 'organic compounds' -- i.e. algae and other microbes -- were able to grow and turn the water a murky green in the subsequent days. The revelation appears to contradict officials' previous assurances that despite the emerald hue, which first appeared Tuesday, the waters were safe." I would personally have avoided using the green pools, but that's just me. "Hydrogen peroxide is sometimes used in pools -- often to de-chlorinate them," reports Ars. "Basically, the chemical, a common household disinfectant, is a weak acid that reacts with chlorine and chlorine-containing compounds to release oxygen and form other chlorine-containing compounds. Those may not be good at disinfecting pools, but they still may be picked up by monitoring systems. Hydrogen peroxide can also be used to disinfect pools but must be maintained in the waters -- not a one-time dumping -- and can't be used in combination with chlorine." Apparently, the green water irritates eyes and smells like farts.
Partly.
The "chlorine" smell in pools is from Chloramines - a compound made of chorine and amines (ammonia). You get more of it from urine, but it'll build up anyway from other sources. The Chloramines are also what stings and irritates the eyes, nose, and lungs.
How do you get rid of it? Raise the free chlorine level in the pool to 10 ppm or so (normal range is 1 - 3 ppm). Presto, changeo, the pool stops smelling like chlorine.
Cryptosporidium is a difficult to remove parasite that can exist in pool water. How do you treat pool water that's been contaminated with crypto? Raise the chlorine level to 10 ppm for 24 hours (20 ppm if you use stabilized chlorine).
Me? I just keep my pool between 10-20 ppm chlorine all the time. Crystal clear water, no algae, no eye irritation, no chlorine smell, no nasties in the water, no side effects at all. My kids swim in it eyes wide open for hours at a time, friends come over and say "I'm glad you don't use too much chlorine; I can't even smell it".
And the worms ate into his brain.
News24 in South Africa had the official peroxide explanation on the 14th already. http://www.sport24.co.za/OtherSport/Olympics2016/rio-diving-pool-drained-of-green-water-20160814
If the bottom end of Africa had it then, then the world had it.
Trying to become famous by taking photos. Visit my homepage please.
Exactly,
Look at Utah (where the games made a profit), all our venues are in use year round. and the village became student housing at the University of Utah as planned. During the winter athletes train and compete at the venues but they are also open to the public to enjoy and try out which serves to recruit new athletes to some of the more obscure events (Lake Placid is the home to the only other bob sled and luge track in the country). And during the summer we find uses for the venues as well. The Ski Jump landing slopes became mega water slides during the summer.
The problem is when host cities throw money at getting the games with no plans beyond the closing ceremonies of the Paralympic games. We not only made a profit during the games but had plans for maintaining and using the venues afterwards.
I'm too lazy to compose a creative sig.
What FC (free chlorine) level is necessary to maintain a sanitized pool is entirely dependent on the current CYA (stabilizer) level. The more stabilizer present, the higher FC level that is needed. CYA is needed to protect FC from UV light but too much is a bad thing. For example, if you have 30 ppm CYA, you MUST maintain at least 2 ppm FC or greater at all times. If your CYA is at 60 ppm, you must maintain at least 5 ppm FC or greater at all times. This is for normal, daily sanitation. Minimum FC = 7.5% of CYA level. Indoor pools, it's not necessary to use CYA, but low amounts (10-30 ppm) can help buffer the harshness of chlorine and allow for easier maintenance of FC levels. Also, to clear a pool of algae, how high you need to raise the FC to fully eliminate algae depends on CYA level. Many times it takes longer than 24 hours of maintaining this higher FC level to clear the algae depending on how much algae, filtration capability... etc. For example, if your CYA is at 60 ppm, you'd need to elevate the FC to 24 ppm and keep it there until the algae is gone. "Shock" level FC is 40% of CYA level.
He who forgets will be destined to remember. - EV