Specialist treatment
pH Correction
(for neutralizing acid water and re-mineralizing very pure water)
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When rain
falls the water has a naturally
aggressive, slightly acidic nature. This water then dissolves chalk and/or metallic deposits present in the local rock strata, which leads to
contamination of the water.
This results in ground and borehole water containing a number of elements
that may not be acceptable for a modern water supply. These contaminants
(such as iron and manganese) then cause problems when the water is put
into use. Acidic water results in corrosion of pipe work, heating
cylinders and equipment. Any iron and manganese present will result in
poor tasting water, in addition to staining baths basins and any
appliances with which the water may come into contact. |
A
pH value below 7 is considered to be acidic, and corrosion accelerates at
pH levels below 6.5, with levels below 6.0 considered to be extremely
aggressive. It is usually difficult to remove iron and manganese from
acidic water, so often the first step in the process is to raise the ph.
The
simplest and safest way to raise the pH is to run the water through a
vessel containing a bed of specially activated limestone. This is a
mixture of calcium and magnesium salts, which are the salts found in
waters of pH greater than 7.0. This limestone gradually dissolves
increasing the pH level of the water. As the limestone dissolves, it will
need refilling periodically. Water with a pH below 5.0 is unsuitable for
this type of treatment but is uncommon.
pH
correction units are available in a wide variety if sizes to cater for all
flow rates, our engineers will carry out a site survey and water test to
ensure the most efficient unit is fitted.
Iron
and Manganese Removal (Turbidity Filtration)
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General
concept of Turbidity filtration-
Both metallic and some non-metallic contaminants
can be removed from water by passing the water through a bed of specialized
media. These media act in two ways: triggering the
precipitation of the contaminant to form an insoluble particle and then
physically filtering out the contamination to leave clean water. By
selecting the correct media, very specific water problems can be treated
easily. Iron
and Manganese can be removed from water by using a media, which encourages
reaction between the contaminant and oxygen present in the water. This
reaction forms an insoluble precipitate which then is filtered out. The
media acts as a catalyst; it triggers the reaction and is not used as part
of the process, giving a long life span from a single filter. The
exact chemical make up of the water changes from region to region, so we
have to select a specific blend of media to match the water that is being
filtered. Three of the main types of media are listed below.
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Gives good removal at a low cost, suited to waters that are of a hard
nature, adversely affected by the presence of chlorine, organic
contaminants and some chemical treatments.
FILOX R.
Has a much higher level of activity than
BIRM, suited for a wide
spectrum of water types. It is chlorine resistant and can also be used to
help in the removal of hydrogen sulphide (a bad egg smell).
Generally only used in industry, it requires chemical
regeneration (with potassium permanganate) to restore its activity
Multi media filters
General
turbidity removal at high flows can be achieved satisfactorily down to low
micron levels using a multi media filter with a layered bed of gravel,
filter sand, and selected filter media. Other specialist media may be
required to improve and polish certain types of water.
In order to remove accumulated deposits from the filter bed, the water flow through the filter is reversed (backwashed). Water is run to drain at a high flow rate to separate the deposits from the filter media.
Nitrate
reduction systems
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The
consumption of water with high nitrate levels causes many problems,
ranging from blue baby syndrome (if fed to babies under six months old) to
a build up in the meat of poultry( leading to
the meat no longer being white).
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Nitrate dissolved in water cannot be removed by simple filtration. It can
only be reduced by either re-generable or disposable ion exchange systems
or eliminated by Reverse Osmosis (RO). RO systems can be used to treat all
of the water for a specific application, or just to remove the nitrates
from a drinking water supply. For single dwellings with one drinking water
tap and low water consumption, a point of use system provides efficient
reduction at low cost. An under-sink unit can be installed with a drinking
faucet- Reverse osmosis. For large or multiple properties, commercial and
industrial applications, re-generable ion exchange systems are preferred.
Ion
exchange nitrate removal is a similar process to water softening, using a
slightly different polymer resin. The resin removes the nitrate (and
sulphate due to its chemical similarity) from the water and replaces them
with chloride ions. Once the resin bed is nearly exhausted of chloride
ion, the control valve carries out a regeneration of the bed. This is
achieved by passing a chloride rich brine solution (made up of common salt
dissolved in water) through the resin bed, which flushed out the nitrate
and sulphate to drain, replacing them with chlorides again. After a final
rinse to remove excess brine the unit is automatically put back into
service again. The only input required by the user is to ensure that the
brine tank is kept topped up with salt.
Again
our engineers will advise the best system depending on the nitrate level
of your supply (up to 93% removal can be achieved using this method) and
the flow rate required.
What to do
now?
Call for an informal chat or to arrange a site visit Tel 01600 860 344