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Breakpoint Chlorination Explained Orenda Whiteboard
>> YOUR LINK HERE: ___ http://youtube.com/watch?v=MvL4ofViikc
Breakpoint Chlorination and Shocking, Explained • https://blog.orendatech.com/breakpoin... • Breakpoint chlorination is the continual process of overcoming the oxidant demand of nitrogen compounds in water, which combine with chlorine. The breakpoint is the threshold of chlorine that indicates combined chlorine compounds (chloramines) have been reduced as much as they can be, and a free chlorine residual can now be formed. In other words, Breakpoint chlorination is the point where chlorine levels exceed the oxidant demand, and the water begins to build a residual of free available chlorine (FAC). • According to the Wisconsin Department of Health, chlorine disinfection cannot proceed until the oxidant demand has been destroyed (http://dnr.wi.gov/regulations/labcert.... If that's even partially true, it's very important to understand this oxidant demand, because chorine's primary purpose is to be a sanitizer and keep our water safe. • The chemical reaction that creates Monochloramine (NH2Cl) looks like this: • 2NH3 + 2HOCl → 2NH2Cl + 2H2O • Ammonia + Hypochlorous Acid yields Monochloramine + Water • Further chlorination of monochloramine creates Dichloramine (NHCl2): • 2NH2Cl + 2HOCl → 2NHCl2 + 2H2O • Monochloramine + Hypochlorous Acid yields Dichloramine + Water • And of course, even further chlorination yields the most noxious of chloramines that off-gasses from pools, Nitrogen Trichloride, aka Trichloramine (NCl3): • NHCl2 + 3HOCl → NCl3 + 3H2O • Dichloramine + Hypochlorous Acid yields Trichloramine + Water • All of these reactions depend on pH and temperature. • Chloramines are weak disinfectants–which is why they are referred to as disinfectant byproducts (DBPs). In fact, many water treatment plants add chloramines to their water as a secondary disinfectant. Albeit weak and slow, chloramines first contribute to the total chlorine levels because they help with disinfection. This, however, reaches a threshold where chlorine turns on chloramines, indicated at point (B). In other words, chlorine oxidizes all contaminants, which includes chloramines after point (B) on the graph. That’s why the total chlorine level drops with the addition of more free chlorine (the X axis on the graph). • The downward trend on the graph shows chlorine starting to “win the fight” against contaminants until it oxidizes all but the combined chlorine residual. This level of chlorine residual is shown on the graph at point (C). If chlorine cannot overcome the oxidant demand, your water’s chlorine demand rises, and the ORP drops. This would look like a more prolonged downward trend toward breakpoint, because breakpoint would be at a much higher dose of chlorine. When the chlorine can meet the oxidant demand, the water has reached breakpoint chlorination.
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