Gary has replied most of your querries with linkage.
The "centralised RO " will still be a better option as you will have less
rejects. A household RO typically works at 15-20% recovery whereas a 100
m3/day RO with Reject Recycle can give up to 60-65% recovery easily. If you
calculate the "Water Saved" , you are there.
About Softening. This water already has "too much Sodium" & "too much
Alkalinity" . If you Softnen further, the Na/TC ratio will not be condusive
& there will be hardness leakage. Also at this hardness & alkalinity the
"feel" of water will be too slimy. We came across such case where we had to
"blend the hardness" to reduce slimyness. What about the " High TDS"
regeneration effluent?. Where is the disposal.
The RO Outlet can be PH corrected before pumping. This will also be a very
stable system as compared to other option. Ro reject will not be as high in
TDS( @ 3000 ppm) as Softner regeneration effluent (normally 7000- 8000 ppm)
Regards !
Shrikant
=================================
thanks a lot shrikant
the total water wastage may not click since they are proposing to install ro
in individual units only for kitchens whereas the central ro would be for
the whole area.and hence the total water wastage may be higher.I am
proposing that they use it for groundwater recharge and gardening.
the point regarding sliminess I will take up with them.I have also told them
that 300 as hardness for a domestic situation is not too hard and they
should be more worried about the chlorides.is that correct?
the point made to
Garry remains-
will the chlorides untreated not be corrosive? is there any other method of
removing them?
Neelesh
============================
Gary has replied most of your querries with linkage.
The "centralised RO " will still be a better option as you will have less
rejects. A household RO typically works at 15-20% recovery whereas a 100
m3/day RO with Reject Recycle can give up to 60-65% recovery easily. If you
calculate the "Water Saved" , you are there.
About Softening. This water already has "too much Sodium" & "too much
Alkalinity" . If you Softnen further, the Na/TC ratio will not be condusive
& there will be hardness leakage. Also at this hardness & alkalinity the
"feel" of water will be too slimy. We came across such case where we had to
"blend the hardness" to reduce slimyness. What about the " High TDS"
regeneration effluent?. Where is the disposal.
The RO Outlet can be PH corrected before pumping. This will also be a very
stable system as compared to other option. Ro reject will not be as high in
TDS( @ 3000 ppm) as Softner regeneration effluent (normally 7000- 8000 ppm)
Regards !
Shrikant
===============================
thanks Gary comments are as under-
I understand and appreciate that the chlorides will not go down with softening I was just wondering if the high chlorides will not interfere with the softening which shrikant deshpande has answered in the affirmative.
I also take the point that the dissolved gases will have to be removed to reduce the corrosion. This can be done by a degasification tower or can we use an activated carbon filter after the ro to remove the dissolved carbon dioxide.? that should be a simple solution is it not?
also the basic question remains. will not the chlorides be corrosive left as they are?
also what is the method of removing them if we just soften the water.
the site is not reachable. could you give me another link please.
Neelesh
================================
First, softening the water will not affect the chloride content of the
water.
Secondly, chlorides or sulfates alone are not the only factors to consider
in determining the corrosivity of water. The presence of Dissolved oxygen
and Carbon Dioxide are added factors. As are any electrical currents that
may be present and aggravated by dissolved ions in the water. These could
be any improperly grounded electrical systems or galvanic or dissimilar
metals cells that may exist in the plumbing. Your proposal of an RO
system would have pretty much the same effect on corrosivity as a water
softener. Maybe even more so because RO will pass any dissolved gases and
those would have the effect of reducing pH. In other words more corrosion
factors. A water softener would have no effect on pH. With the water
analysis you provide one would also expect to have to treat the resulting
water to reduce the corrosiveness of the water regardless of the method
used for mineral reduction.
A good web site to visit is
you a better idea of the various corrosion causing factors. It will not,
however, support your claim that reducing all mineral content of the water
will make the water less corrosive. In addition to any mineral reduction
one needs to also treat for water corrosivity.
Gary Schreiber, CWS VI
The Purolite Co.
========================================
dear friends,
we have come across a water sample with the following parameters
TDS 1698
hardness 325
Tss 3
ph 7.9
sulphates 175
chlorides 490
nitrates 11
iron o,10
alkalinity 1240
silica 0.7
the total water requirement for the building housing 70 families is about
100 m2/day.
we had proposed the installation of a reverse osmosis unit which would
reduce the TDs level and reduce all contaminants to make the water
potable.however someone else has suggested that they install a softener
and install individual ro units for drinking water in each flat.
I strongly felt that the water could become soft but yet the chlorides
would ultimately corrode the pipes. besides the alkalinity would cause
taste problems when rinsing etc.
my questions are-
will the chlorides interfere with the softening process if so how?
even if the water is softened will not the chlorides along with the
sulfates cause pipe corrosion?
can you suggest some sites or links which can corroborate your opinion
particularly about the corrosion to pipes etc due to the high chlorides
which softening will not remove.
is there any other method of removal, of the chlorides besides dm?
the reference to the links are very important since the client wants
irrefutable proof that I am right independently corroborates since the
company that made the initial recco is much larger than mine and carried
more weightage in the client mind.
Neelesh
> I would appreciate if any one can help with a problem that I have never
> encountered before.
>
> A customer of mine owns a 20 year old Kinetico model 30 water softener
> that
> has what appears to be green algae growing internally. It is visible
> inside
> level 1 through the clear top cap. The valve was rebuilt, resin replaced
> and components sterilized with chlorine about 6 months ago but the problem
> has returned. The customer also complains of a musty smell on the soft
> water only. It is installed on a chlorinated municipal water supply.
>
> Any advice on the best way to kill algae?
>
> Ken
Hello Ken...would you consider an option of an Electronic Water
softener?....to replace or work with it..also this unit prevents broadweed
in ponds...look into the technology...
Sincerely ...Terry
Team Enterprise..... it takes very little to put things right
130 Linwood St.
London, Ontario
N5Y 1W4
519.455.1468
======================================
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