Portuguese domestic well water

[petermeachem]

We are buying a house in Portugal that has a well. Can anyone give me a starter on methods of treating the water so that it is ok to use around the house. I know absolutely nothing about the subject, except that I am told there is a high iron content. We need something that works automatically without intervention as we won't be there most of the year. The water will be used for washing etc, drinking would be a bonus but the locals seem to use bottled water for this, so it wouldn't that isn't so important. Size is also a factor. I need to build a shed for water and power and would rather it wasn't too large. We recently stayed in a house fed by a well that used 3 1000 litre tanks with filters. Took a lot of space.

 

[hydrae]

two questions

Iron
The classic treatment for iron is to add an oxidant such as chlorine, potasium permaganate, or ozone, which will oxidize the iron to a rust which is then removed by a filter containing granular media such as sand, antracite, greensand. (if the iron content is low, less than ~2 mg/liter you can sequester the iron using a polyphosphate)
The filter is typically sized at 2-5 gpm per sq ft (75 to 150 liter per min per sq meter). So the diameter of the tanks is proportional to quanity of water out of the well.
In either case this will require equipment that requires maintenance during well operatation. The maintenance includes replacing the oxidant when it runs out and, the filter(s) will need backwashing, the filter manufacterer can provide automatic controls to do this. If you have two or more filter vessels you can use the water from one to backwash the other but with one vessel it requires stored water and additional pump. Getting the oxidant dose correct requires trial and error.

A simple system that may work, the device drops a calcium hypochlorite tablets down the well for every 30 gallon (100 liter) produced. The iron is oxidized in the well and drops to the bottom of the well. But check local codes to see if this is allowed. USA Bluebook pg123

Having iron in the water is not unheathly but it will turn everything brown as the iron comes out of solution and promotes the growth of iron bacteria.


safe to drink
your primary concern is bacteria. A well constructed using good seals and drawing from a aquifer below a confining layer will be safe to drink if it has not been contaminated. Note wells are easy to containminate and hard to cleanup. Have the water tested for coliforms on a least a yearly basis if you wish to drink it.

 

[petermeachem]

Thanks very much for your reply. I didn't get email notification for some reason. I'm going out to Portugal soon so I'll bring a sample back for analysis.

 

[bimr]

The "classic treatment" for iron removal in a residential application is a water softener. Water softeners work resonably well provided the iron content is not too high and will continue to operate relatively unattended except for periodic salt replacement.

What hydrae has posted will work, but is not done very frequently because of the need for more maintenance. Most people don't want to do it.

Not too familiar with Portugal practice, but another aspect is the service business. With the service business, someone comes to your house to changeout the tanks on a periodic basis.

European practice leads to higher water quality standards. For that, carbon filters are commonly used to upgrade the water quality (improve the taste and odor).