Friday, December 14, 2018

Use of Reverse Osmosis (RO) Filters in Developing Countries?

Dear Chen Ko

May I know what is your opinion on filters using the RO process? Will the result be water that is too “pure”, extracting both harmful components but removing beneficial minerals as well?

Specifically, I just received a 2nd hand filter, the Elken Bio Pure Narisia S250 which uses RO - however, they are distributed by a MLM company, so am somewhat skeptical of bringing this to use in developing countries (e.g. Vietnam, Thailand).

Locals have told me the water infrastructure has problems in their piping (metals) and water sources contaminated (industrial pollution). One would not drink tap water, unless boiled. Even then, it has its risks after boiling. Was wondering if you could share some light on such a filter's practicality there.

Thank you, and wishing you a good week ahead.

Warmest regards


Hi Thomas,

You did not mention whether you are bringing the Elken unit to Thailand, Vietnam for short term or permanently. Or are you going to be carrying it around with you from SG to other countries and back?

A few thoughts…

1.       To me, the logistics of packing such a unit to various countries do not sound appealing, especially on a short term basis. Hooking up the unit to the piping and making sure there is electricity (you have consistent electricity there, don’t you?) can be a hassle.

Getting replacement parts (e.g. filter cartridges) in your foreign country may also present a challenge, especially if they do not last long.

2.       You may want to read my article “3 Critical Questions to Choosing Your Water Filter” for a better understanding of selecting the right water filter.

3.       In short, there are 3 major considerations.

a.       Based on your water source, what contaminants do you expect to find in your raw water? You cited metals and industrial pollution. You may want to find out more (possibly from the local authorities and reports) and be more specific.

b.      Are the contaminants in the raw water of concern? Are their concentrations in water of concern? You may refer to the WHO drinking water guidelines for these answers.

c.       And most importantly, can your chosen water filter remove those contaminants of concern or at least reduce their concentrations to safe limits? I have checked up the Elken website and could not find your particular model. And for the other models, I can hardly find any documentation to their contaminant removal efficacy.

You may want to contact the company directly on whether it has any official documentation, preferably scientifically tested by an accredited laboratory on the performance of your water filter. The documentation should state clearly that the water filter can handle your contaminants of concern.

Of course, the gold standard is for the filter to be certified under NSF/ANSI 58 which pertains to RO treatment units. I don’t seem to find such certification mentioned on the Elken’s website so the chances of certification should be low.

To be honest, a well designed and built RO unit can remove (or at least reduce) a lot of water contaminants. The question is: is yours well designed and built? Being sold through an MLM structure, I am sceptical of the amount of development and testing that goes into your water filter since most of its costs go towards paying the hierarchy of marketers.

4.       As for your first concern on the purity of RO water: if I am going to use the filter on foreign water of questionable quality, I will be a lot more worried about the contaminants in the water and whether my filter can effectively remove/reduce them.

But let’s say you only use your RO unit in good, old SG, will the purity of the product be harmful? It seems that the main issue of very pure water (provided your unit is well designed and built) is its ability to leach stuff out of its containers or piping. Therefore, my suggestion is as much as possible, store such pure water in glass containers for minimum leaching. If you find glass too heavy or fragile, then stainless steel is next best. Obviously, use only food grade materials.

Figure: For serious filtration of raw water of questionable quality, I will bring my Doulton along. My version is a bit bulky but it can serve a family easily. It also comes in a smaller size. Similar and perhaps even better is Big Berkey. Both are well recognised and documented water filters that do not need electricity to work.