#61 ·
It’s not really about that; it's more about a fundamental misunderstanding of the subject. He’s talking about laying pipes and disinfecting the lines themselves, but we’re discussing water disinfection. He doesn't seem to grasp that residual chlorine isn't added in excess because we can't accurately predict its concentration—it's added because maintaining a residual is legally required! A place like Bozeman is a perfect example where they use UV for disinfection, but when they switch it over to the supply system, they dose in chlorine. That residual stays there because none of what's dosed gets used up immediately; it just travels through the pipes.
like this:
The considerations for wastewater treatment are different from those for drinking water treatment. For example, U.S. EPA regulations require drinking water systems (regardless of the primary disinfection method used) to maintain a "residual" level of chlorine in treated water to prevent recontamination in the distribution system. On the other hand, wastewater systems usually need to remove residual chlorine before releasing treated effluent.
or in plain English :-)
Along with the chemical and microbiological indicators mentioned, it’s often a case of
misunderstanding the concept of drinking water disinfection, specifically regarding chlorine as the
most common disinfectant. Its purpose is to prevent potential contamination
during transport and to preserve the water from the moment it's pumped until it's consumed. The allowed
concentration is 0.50 mg/l. It is automatically dosed (with a maximum final
concentration of 0.30 mg/l) and electronically monitored. Since some of it is consumed within the network,
its concentration at the tap will never exceed the initial amount. Two phenomena
related to water disinfection at the consumer level often create the impression of "over-chlorinated water":
1. The human threshold for detecting chlorine by smell is very low, sitting around 0.05 mg/l, which is significantly
below the legal and actual concentration present.
2. "White water," which clears up in a glass as tiny bubbles rise, is actually
dissolved atmospheric air caused by technical work on the lines. When that water "degasses,"
that air carries dissolved chlorine with it, intensifying the "chlorine smell."
______________________________________
Debates about whether disinfection in public water supplies is beneficial or harmful are pointless because
this is a public health measure. Along with vaccinations, it has contributed most to extending
human life expectancy and reducing mortality, especially in young children, while improving
general living conditions. We see evidence of this in less developed parts of the world, where there is still a high prevalence of cholera
outbreaks and diseases linked to unsafe water.
With all due respect to his professor, he’s going to have to spend a lot more time in school before he can complain about something he clearly doesn't understand from this perspective (unless he is strictly talking about disinfecting pipes rather than the water itself, in which case I don't know and I'll back off—but as far as I can tell, we're talking about chlorine in the water).
like this:
The considerations for wastewater treatment are different from those for drinking water treatment. For example, U.S. EPA regulations require drinking water systems (regardless of the primary disinfection method used) to maintain a "residual" level of chlorine in treated water to prevent recontamination in the distribution system. On the other hand, wastewater systems usually need to remove residual chlorine before releasing treated effluent.
or in plain English :-)
Along with the chemical and microbiological indicators mentioned, it’s often a case of
misunderstanding the concept of drinking water disinfection, specifically regarding chlorine as the
most common disinfectant. Its purpose is to prevent potential contamination
during transport and to preserve the water from the moment it's pumped until it's consumed. The allowed
concentration is 0.50 mg/l. It is automatically dosed (with a maximum final
concentration of 0.30 mg/l) and electronically monitored. Since some of it is consumed within the network,
its concentration at the tap will never exceed the initial amount. Two phenomena
related to water disinfection at the consumer level often create the impression of "over-chlorinated water":
1. The human threshold for detecting chlorine by smell is very low, sitting around 0.05 mg/l, which is significantly
below the legal and actual concentration present.
2. "White water," which clears up in a glass as tiny bubbles rise, is actually
dissolved atmospheric air caused by technical work on the lines. When that water "degasses,"
that air carries dissolved chlorine with it, intensifying the "chlorine smell."
______________________________________
Debates about whether disinfection in public water supplies is beneficial or harmful are pointless because
this is a public health measure. Along with vaccinations, it has contributed most to extending
human life expectancy and reducing mortality, especially in young children, while improving
general living conditions. We see evidence of this in less developed parts of the world, where there is still a high prevalence of cholera
outbreaks and diseases linked to unsafe water.
With all due respect to his professor, he’s going to have to spend a lot more time in school before he can complain about something he clearly doesn't understand from this perspective (unless he is strictly talking about disinfecting pipes rather than the water itself, in which case I don't know and I'll back off—but as far as I can tell, we're talking about chlorine in the water).