Removing excess conductivity

However the conductivity remains in high, over 500 uS/cm which is not desirable for drinking water.
I don't agree with that statement.
Surely it depends what is causing the high conductivity?
Sodium chloried for example would be bad, but some calcium compounds are beneficial to the bones.
The water where I live (Essex UK) is about 0.7mS (relatively hard).

Del

You are absolutely correct in your desire to avoid RO in your environment. Although very effective when operated and maintained properly, such systems can multiply your cost of water production by a factor of 4 or more, just on the basis of the cost of electricity. The real kicker though, is the limited availability of skilled people to maintain the system. My experience tells me you could expect something like six months service out of an RO system under these conditions, in spite of manufacturer's warranty...

Regarding the "excessive conductivity", I agree with the others that you must first determine what is causing the conductivity before you can determine if this is really harmful or undesirable for drinking water. As others have noted, high mineral content is not necessarily detrimental, and may, in fact, be healthier to drink. It all depends on the minerals dissolved in the water. One thing that must be watched however, is that the chemical composition of the water does not change radically as the aquifer is drawn down during normal usage. If there is electricity available nearby, there is a good chance that there are potential pollution sources nearby that could leach in to the aquifer and destroy it for consumption purposes.

In short, hardness and conductivity testing are nice for monitoring water condition testing, but really do not provide enough information to establish if the water is truly safe to drink. You need a complete chemical analysis for that.

Your water softener replaces water hardness cations (Ca, Mg, Fe, etc.) with Sodium (Na). Not the best choice for drinking water, but good for washing or process water. Passive solar distillation is your cheapest bet in rural areas, you will need both chemical and bacterial testing to determine final safety in undeveloped areas. The old polyethylene covered pit with the feed water drizzled in around the upper edge like they used to teach Boy Scouts is a good system for single-family use.

A conductivity of over 500μS/cm at 20degC would fall within World Health Organisation parameters for "potable water".

The conductivity level is equivalent to a well-water source available here, which is drunk after filtering to below 5μm and zapped with an ultraviolet source for rendering any bacteria innocuous.

Guys & gals (if any),

I am sorry for not keeping you informed of the progress. I have been extremely busy!

We went ahead and implemented this CSR project and I am happy that system is working well.

This is for a school. There are only 2 wells in the village and one in in the school.

Raw water hardness is over 450ppm and with our treatment comes down to below 20ppm.

Conductivity of raw water is around 550 μS/cm and goes up slightly to around 600µS/cm.

Water after treatment is crystal clear,free of bacteria & virus very much suitable for drinking, million times better than what we start with. It passes all guidelines by WHO and also maximum permissible national limits.

However under national standards there are two parameters Maximum Concentration Desirable and Max. Conc. permissible. For conductivity it is 3500 & 750 respectively while for hardness it is 250 and 600.

Still I feel if we can improve on the parameter conductivity I would love to do it. In fact what I expected was input from someone who has used low pressure membranes ultra filtration or nano filtration. I wish to know whether ultra or Nano membranes make a difference in conductivity. I know for sure RO membranes do, but they need high pressure pumps and process is more complicated.

By the way for these poor people who had been living a hellish life of 3 decades under ruthless LTTE terrorists and hypertension and/or Sodium is and will not be a problem for at least one generation!

"I wish to know whether ultra or Nano membranes make a difference in conductivity."

No: they can only remove molecular size suspended solids. Only RO membranes can remove dissolved ions.

Thanks Dvader, Your contributions in this field have been always very helpful.

Dear Sisira,

Suggest go through information available at

http://barc.gov.in/technologies/home.html.

Bhaba Atomic Research Center, Government of India have developed number of technologies aimed at providing potable drinking water to poor and back ward regions of third world countries.

Regards

You need to spend money to make money like hiring people with skill.

well can you please explain what you mean?