Como dizer "tratamento de água" em inglês

Just to clarify something...

(1)
Water Treatment = Tratamento de Água
Wastewater Treatment = Tratamento de Água Resdidual/Residuária; Tratamento de Efluente

(2)
You don't usually treat water from a river because you treat it before it goes (back)to the river.

Henrique

Henry, what I meant to say was that you don't treat water from a river like adding chemicals to the river and it's done. I wasn't thinking about water for human use at all. All city water is treated for human use, even though It's not 100% treated.

"Water Treatment" is a general term for treat the water for any use.
Industrial Water, Drinking Water, Shower Water, Cleaning Water, Irrigation Water, etc, all of them have their water quality parameters and that means different water treatment processes.

If you treat effluent water that you catch from a river and don't send it to some sewage treatment plant (STP) like SABESP, SAEE, etc, but you return it to the river, it must be within a range of quality parameters (pH, Temp, dissolved solids, conductivity, etc) prior to return it to the river.

If you treat water for use in a home-brewing process or something, the quality may not be the drinking-water quality and a softener or an ultrafiltration system (Reverse Osmosis) may be required.

I don't understad a lot of the city-water catchment, treatment and distribution, only what I've learned in Enviromental Engineearing Classes which I didn't paid a lot of attention to. However, I really understand about Water Treatment proccess for Industrial uses and disposal.

Sorry about grammar errors, hope it sounds clear and understandable.

Bye

Well, actually Henrique, all water is treated before it goes into human use, and it is all treated after human use. River water isn't generally considered "clean" as is, particularly around large urban centres. And treatment often involves adding fluorine, for instance, a dental decay prevention mesure.
I'm not an expert on the matter, but there may be a difference in the degree of treatment between affluent water feeding into a city's drinking water system, and effluent (wastewater) flowing out of the system. See here, for instance, where there is a clear distinction between drinking water treatment and wastewater treatment: http://www1.toronto.ca/wps/portal/conte ... d60f89RCRD

Following from my previous post, I went and read the info on how Toronto handles water in all its manifestations. I'd forgotten about another part of the system, which deals with "storm water" -- you know, the stuff that comes down as rain or snow. So for the most part we have three water delivery and withdrawal systems in the city -- all of which have treatment systems associated with them: supply of treated fresh (drinking) water, removal and treatment of wastewater (from toilets, baths, sinks), and removal of stormwater (from rain, snow, water used to water your garden, for instance). I didn't realize, for instance, that this restriction exists:

"Wash vehicles at commercial car wash facility (It's illegal to wash your car on your property if the water runs into storm sewers.)"

Now I have a legitimate reason to never wash my car in my driveway. Nice.

Jerry, estava frase pode ser usada: The river needs a water treatment. , ou há uma expressão mais simplificada?

Aproveitando este tópico, trago a tradução para "estação de tratamento de água":

Wastewater treatment plant

A wastewater treatment plant (WWTP) or wastewater treatment works is an industrial structure designed to remove biological or chemical waste products from water, thereby permitting the treated water to be used for other purposes. Wikipedia