Removing Nitrates from Your Drinking Water
Nitrate Removal From Your Drinking Water
Nitrates are commonly found in UK water, particularly in private water supplies (wells, boreholes etc).
Their presence is often the result of over-fertilisation by farmers but can also be caused naturally eg by rotting vegetation.
Nitrates are particularly prevalent in agricultural areas ie where fields have been sprayed. The rain washes the fertilser off the fields into aquifers which eventually end up in the water supply.
The limit for nitrates in drinking water is 50mg/L (WHO / EU and UK's Drinking Water Inspectorate).
Adverse Health Effects.
Standard / allopathic medicine concerns focus on Methemoglobinemia aka Blue baby syndrome. This is very rare - the last case in the UK was in the 1950s - but it can be fatal. It is certainly a risk with untreated water.
Alternative health concerns: very few it seems.
If you are on normal mains water you are unlikely to need to worry too much about nitrates unless you have a particular issue with it - in which case see just below for solutions to remove it from your drinking water.
How to Remove Nitrates
This depends on whether you want to remove it from your drinking water only or from the supply to your whole property:
A) From Your Drinking Water
Unfortunately you can't simply boil water to remove nitrates. Like many chemical pollutants, boiling it will have no effect. (In fact the nitrates might simply increase in concentration because the water evaporates leaving a higher proportion of nitrates to water).
Nitrates can be filtered out from your drinking water by the following methods:
- Distillation (thorough but fairly long-winded and impractical)
- Ion exchange (aka various "Nitrate removal resins" in cartridges which are maintenance heavy and not thorough. Performance declines over time)
- Reverse osmosis
The latter ie a reverse osmosis water filter is our recommended solution for reducing nitrates in your drinking water supply.
Not only does RO remove a wide range of other contaminants from your water but it will maintain the same level of performance for the life of the filters.
This compares well with Ion exchange resin cartridges which, at the beginning, work at say 80% effectiveness during the first Month, and then decline to minus 60% in Month 3, and so on.
Reverse osmosis will typically remove between 50% to 90% of nitrates - the actual percentage will depend on what else is in your source water* but you can expect it to be at the highest end of that scale ie nearer to 90%.
*(For example sodium and / or sulfates, and a low water pH will all reduce the effectiveness of nitrate removal).
B) Removing Nitrates from the Supply to Your Whole Property
Nitrates can be removed using a similar unit to a salt water softener, however instead of using softener resin, you would use nitrate removal resin.
This will need regenerating with salt - hence the similarity to a salt water softener.
You would need to give us specifics on your requirements but to give you an idea:
A typical (large) unit would be capable of a flow rate of 1.2m3/hr and have a capacity of 5.1m3 per regeneration.
The unit would work on a metered capacity rating so when it knows the media inside is expired, it would regenerate and make it reactive again to the incoming water.
Each regeneration would use 4.4kgs of salt.
So on average this unit would use around 9kgs of salt per week to remove the nitrates. (A cost of about £3 per week - much cheaper if you buy in bulk).
Every 10 years or so the media itself would need replacing (Cost for this size unit would be about £125 at current rates - ie £125 every ten years).
Please note: If anyone suggests you use cartridges to remove nitrates, politely ignore them.
This is because a large cartridge holding 4 Litres of resin would filter only 500 Litres of water.
Expect to pay at least £20 or more for each cartridge.
So you can see how buying a nitrate treatment unit, with it's higher upfront costs is much better value in the medium term.
(See the picture below for how your new unit would look).
How Much Would it Remove?
Nitrate resin when working correctly, and with the correct contact time (ie not exceeding the max flow rate) , will usually give a removal of 90% efficiency.
Where to Install it
Typically a nitrate removal filter for the whole house would be installed before the water tank. (Almost any property accepting a private water supply will have a holding tank).
This is because the flow rate into a tank is much more constant - and slower - than on the outlet side, where the outflow will depend on how much water the property happens to be drawing from the tank.
The private water supply should almost certainly have an Ultraviolet filter aswell. (The UV would always go after the tank).
These units operate with a standard 3 pin plug 240V
If you need a nitrate removal filter for your whole property please contact us to discuss your needs by email or phone and we'll be happy to give you a free customised quote.
Image: A typical large nitrate removal filter