Photophilic formation of bromate prevented in California's Ivanhoe Reservoir through the addition of black balls.
I'm a little dubious of Gizmodo's description of the chemistry of bromate formation - I don't think sunlight combines chlorine and bromine to form bromate. I think it's more likely that the energy from light (and heat) helps drive the reaction where chlorine frees/replaces bromine from various bromide salts in the water, leaving the bromine free to react with ozone (which is used in the water disinfectant process, or just occurs naturally from the combination of direct sunlight and water vapor over the reservoir) to form bromate. The benefit of the balls would be, primarily, to keep the system energy/temperature down and prevent ozone formation, yes? Any input from the resident chemists, Wax or Sherv? I took solid-state chemistry and organic chemistry over inorganic chemistry (8 years ago) so this is a stab in the dark (ha-hah). I miss Dylan Stiles and his Tenderbutton Chemistry Blog.
For more information on the formation of bromate in purified drinking supplies: [1]. [2]. [3], [4], [5].
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I'm a little dubious of Gizmodo's description of the chemistry of bromate formation - I don't think sunlight combines chlorine and bromine to form bromate. I think it's more likely that the energy from light (and heat) helps drive the reaction where chlorine frees/replaces bromine from various bromide salts in the water, leaving the bromine free to react with ozone (which is used in the water disinfectant process, or just occurs naturally from the combination of direct sunlight and water vapor over the reservoir) to form bromate.
* Water destroys ozone in a fairly short period of time,
* the interchange between air with an ozone level of "1 ppm" to meet "instantanous demand" on potable water would achieve really insufficient ozone to generate detectable hypobromous acid, much less the much slower bromate formation reaction.
I'd look to carbonate as the oxygen source.
The benefit of the balls would be, primarily, to keep the system energy/temperature down
Surface temperature will increase. The reservoir will stratify.
and prevent ozone formation, yes?
Photoproduction of bromate from chlorine dioxide is well doucmented. Not that this reservoir used chlorine dioxide, but that photoproduction is a well known phenomenon.
Sorry, I am just a MechE, but I have been fighting the dispensation against bromate by the US-EPA for a while.
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