The filter and connection kit, installed on my Camelbak hose

Review: Water purification methods- Filter vs. UV vs. Tablets

Background

I’ve just returned from my 2 week trek to Everest Base Camp, which took me from Kathmandu, Lukla, Phakding, Namche Bazaar, Periche, Dingboche, Lobuche, Gorak Shep and a whole host of small villages in the Himalayas on the way back.

Across the entire journey (including Kathmandu), every guide book and travel advice centre highly recommends that any water consumed (unless it is bottled) be treated.  Whilst bottled water can be purchased along the trail, it can get very expensive as all these bottles need to be carried up on the backs of porters or animals (yaks, donkeys, or half yak/cow hybrids).  The empty bottles also pose a significant environmental problem as there is no immediate way to recycle such bottles in the mountains, nor any organised method to transfer the waste back to a place to be recycled.  Due to these reasons, trekkers are highly encouraged to take water from local sources, treat then consume.

Water treatment methods

When deciding on how to treat water, there are so many different methods to choose.  For me, practicality reasons narrowed it down to four main methods:

  1. Boiling,
  2. UV,
  3. Filtration; or
  4. the use of water purification tablets.
Boiling

Boiling was ruled out as the amount of energy required to boil up 4-5 litres a day was more which I could carry, not to mention the extra equipment required to do so.  Also, water would have to then cool before I could drink.  The time spent at boil would have to be increased due to the lower boiling point of water at altitude as well.

UV

This was an attractive option as all I would need is a bottle and a device such as a SteriPEN and a few AA batteries.  Basically, if you are able to source clear water, you can use this device to kill bacteria using UV light.  How it works is explained here.

Supposedly, a set of Lithium AA batteries is enough for 150 uses, or 150L of water.

I managed to pick up a SteriPEN Classic from REI when I was in the US for $60USD I think…  Which is much below the price in the UK and Australia.

Water filtration

Water filtration methods can be an instant source of clean drinking water.  By passing water through various membranes and filter materials, bacteria, viruses etc are filtered out.  Filters can come as hand pump systems, straws, in-built into drink bottles (not to be confused with the taste/odour removing filters for drink bottles which you can purchase – these do not filter the bacteria etc) or as systems which can be connected in-line to a hydration pack like a CamelBak.

This last option was appealing to me as it meant I could fill my Camelbak with water from whatever source (within reason) and just suck it through the filter as clean drinking water.

After Googling and searching the net, I found the Aquaguard Micro 3-in-1 product from Drink-safe Systems.  As they were having a Spring sale at the time of purchase, offering 15% off, I was sold, so I bought one.  The normal RRP is £48.95 with a connector set, or £38.95 without the kit.

Water purification tablets

There are so many different products available out there for hikers that I’m not going to go through them.  But basically, you get these tablets, typically priced anywhere from $3-$10 for a pack of 10 to 50.  Each tablet (unless you buy the super strength camp-group ones) treat 1L of water.  Any sediment should be filtered out before hand (such as with the use of a UV steriliser), drop the tablet in, wait a prescribed time for the tablet to dissolve and kill the bacteria and viruses (anywhere from 30min to 1.5hrs, also dependent on water temperature), then drink away.

Some tablets do affect the taste of water, others not so.  You can also buy neutralising tablets which remove any taste which other tablets may have.

As a third method, I bought a pack of 50 Oasis Water Purification tablets (active ingredient: Troclosene Sodium, NaDCC) for £2.00, ‘to be sure to be sure to be sure’ as they say…  Each tablet treated 1L.

How they performed

So across the two weeks in Nepal, I found that I relied on the SteriPEN UV for treating water for my drink bottle and the Aquaguard Micro for my bladder.  I did not use any tablets, through everyone else in my group used them, so I’ll use their observations.

SteriPEN Classic

The SteriPEN takes up little room in your bag and the Classic kit which I bought included a pre-filter attachment which could be screwed onto a Nalgene polycarbonate drink bottle.  The prefilter is a two-piece unit, with the filter part being removable once water is in the bottle to allow the attachment of the SteriPEN.

The pre-filter is for filtering out sediment only, much like straining water through a cloth.  If you have access to clear untreated water, this should be unnecessary.

The blue collar on the unit is rubber, which allows you to seal the unit on a standard sized drink bottle if you wish.

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SteriPEN Classic- Carry case, unit, cover, pre-filter and pre-filter attachment for drink bottle (fits Nalgene wide mouth)
Nalgene with prefilter screwed on.
Nalgene with prefilter screwed on.

The nipple on the prefilter isn’t for drinking water out of – it is to let air inside the bottle escape as water is filtered in.  Filling a bottle can be down from a tap or similar source, or by submerging the bottle in a water source.

Pre-filter with exhaust nipple.
Pre-filter with exhaust nipple.
Open the nipple to allow air to escape as you fill the bottle.
Open the nipple to allow air to escape as you fill the bottle.

Once your bottle is filled, you can twist out the filter piece and jam in the SteriPEN.  You then press once and wait for the light to blink to sterilise 1L or water, or press twice to sterilise 0.5L or water.

Take the pre filter out and jam the SteriPEN in
Take the pre filter out and jam the SteriPEN in

After pressing the button, you need to ensure water bridges the electric contacts on the SteriPEN.  These are sensors which determine when the water is ready for drinking.

Turn the bottle upside down to bridge the connections, which turns on the light.  Shake around to 'agitate' the water to ensure all is sterilised.
Turn the bottle upside down to bridge the connections, which turns on the light. Shake around to ‘agitate’ the water to ensure all is sterilised.

If you have access to clear water to begin with (non-cloudy, no sediment) then the water can just be poured into the bottle and stirred around with the SteriPEN.  For the most part of the trek, this is how I used it.

Alternatively, use the pen to stir the bottle.
Alternatively, use the pen to stir the bottle.

In terms of battery life, I used a set of Engergizer Lithium AA’s and used the SteriPEN 3-4 times a day (1L each time).  Others in the group also occasionally used it.  The single set lasted the entire trip.

SteriPEN recommends the use of NiMH or Lithium AA's for maximum battery life (150 uses) vs alkalines (50 uses)
SteriPEN recommends the use of NiMH or Lithium AA’s for maximum battery life (150 uses) vs alkalines (50 uses)

I can say that from all the sterilised water I drank from my Nalgene, not once did I get or feel sick in any way.  I had no issues with the unit, just fill the bottle, press the button, stir and drink, whilst watching others who were using their water purification tablets sit and wait whilst their tablets dissolved in their water… 😛

The only time I felt uncomfortable in using the SteriPEN to treat my water was when I was in Gorak Shep, when the water given to be in my bottle was a little cloudy.  In that case, I just poured it into my CamelBak and used my water filter instead.

Drinksafe Systems Aquaguard Micro 3-in-1 Filter

The other primary method of water treatment for my trip was the use of the Aquaguard Micro 3-in-1 filter which I installed on my hydration bladder tube.

The filter and connection kit, installed on my Camelbak hose
The filter and connection kit, installed on my Camelbak hose

The kit I bought included a set of quick-fit adaptors.  These are not the same as the ones used by Camelbak, but are of similar quality.  To install them, just cut your tube, dip the ends in hot water to soften, then push them in place and cool under running water.

Throughout the trip, none of these fittings leaked.

The quick-fit fittings allows you to quickly install the filter or remove it when not required. Even though you have to cut your hose, you don’t actually lose any ‘length’ out of it.

The quick-fit connectors supplied allow you to quickly use or remove the filter from the hose.
The quick-fit connectors supplied allow you to quickly use or remove the filter from the hose.

The actual filter unit is partially serviceable, as you can open it up and clean the blue sediment filter inside.  Some chalk tape is also supplied in the fit to ensure the screw fittings are water tight.

The filter unit also has a sediment filter in-line to the main filter.  This can be taken out and rinsed.  Also allows you to clean the filter surface.
The filter unit also has a sediment filter in-line to the main filter. This can be taken out and rinsed. Also allows you to clean the filter surface.
The filter unit installed inline with the hose.
The filter unit installed inline with the hose.

As you can see in the image below, the unit is not very big and I can say that it is not very heavy either.  It fits nicely with the bladder in my day pack.

I purposely located the filter near the top of the bladder, so that when I start drinking, the empty space created by the reduced water level will furthermore hide the filter in the bladder pouch in my bag.

Compared to not having a filter, the water flow rate through the mouthpiece is noticeably reduced.  However, once the filter is primed, you can still use gravity to ‘drip feed’ water through the filter, albeit at a slow rate – maybe 1L/2-3min?

Sucking water through the filter wasn’t very hard, even when you’re short of breath, but you do notice the filter being there.

Filter unit with a Camelbak Omega hydration reservoir.   I cut the hose at that position to locate the filter near the top, as when water is consumed from the bladder, the top obviously empties first, making more room for the filter unit.
Filter unit with a Camelbak Omega hydration reservoir. I cut the hose at that position to locate the filter near the top, as when water is consumed from the bladder, the top obviously empties first, making more room for the filter unit.
Again, the quick fit adaptors allow for the easy use of the bladder without the filter.
Again, the quick fit adaptors allow for the easy use of the bladder without the filter.
An 'anti-kink' wrapping is supplied with the kit.  I found that I did not have to use it.
An ‘anti-kink’ wrapping is supplied with the kit. I found that I did not have to use it.

If you want to use the filter to fill a drink bottle, you can use the supplied water tap connector.  To use this, I had to unscrew one of the quick-fit adaptors.

A tap connection is also supplied.  I used one of the included connectors to connect it to the filter.
A tap connection is also supplied. I used one of the included connectors to connect it to the filter.

The tap connection provided a good seal with a range of taps, good enough to filter water without having to hold it in place.  The filter unit never felt like coming off from a tape, if you control how far open the tap is!  Warning, turn it on slowly!!!

Can be attached to most taps to be an source of clean water.
Can be attached to most taps to be an source of clean water.

Likewise, you can easily reverse the fittings to back-flush the filter using a clean water source.

Connections can be reversed so you can 'back-flush' the filter after use.
Connections can be reversed so you can ‘back-flush’ the filter after use.

The best part of this system is that it really water an install and forget product. After installing the filter to my Camelbak, I only had to hand my bladder over at the various tea-houses to be filled up and I would just suck the clean water through throughout the day as I needed it.

All of the fittings provided were top notch and there were no leaks.  Hose kinking wasn’t an issue for me and the water which came out tasted good.

I guess the only thing I couldn’t do was to use electrolyte flavourings in the water inside my hydration bladder, as this would then be filtered through before drinking, so the entire journey, I just drank plain water from my bladder.

I used by Nalgene bottle with SteriPEN treated water with the electrolyte mix which I had instead.

In the case where the source water was a little cloudy, I drip fed filtered water from my bladder into my Nalgene bottle and then added the electrolytes.  Again, it took around 2-3 minutes to fill a 1L bottle with the reduced flow rate through the filter.

As with the water treated using the SteriPEN, I never had any issues with drinking the Aquaguard Micro filtered water from my hydration bladder.  Installation was easy.  Using it was even easier and I can definitely vouch it’s effectiveness.

Water Treatment Tablets

I was the only person in my group to not use water treatment tablets to treat the drinking water for the entire trek.  Whilst the other 15 people had a range of different tablets (some used chlorine based tablets, others iodine, others Sodium Troclosene and Sodium Troclosene with Silver Nitrate etc), each had different experiences.

Some complained about the taste, whilst for others it was fine.  But all had to wait a particular time (at least half an hour) before they could consume water.  This meant that they had to manage their water consumption to ensure that they always had treated water on hand when they were thirsty, to ensure they were not tempted to drink water before the treatment period had elapsed.

I do have to say however, that when using the tablets, no one in my group got sick (to my knowledge), so whatever they used was effective enough and cheap at the same time.

Conclusion

Ultimately, it was this ‘waiting time’ which persuaded me to see alternative methods to water treatment tablets to treat my water for this trek.  The SteriPEN deal was too good to pass up, with the unit being on discount when I purchased it in the US and the simplicity of the in-line Aquaguard filter had me sold.

Both methods involve a significantly higher up-front cost vs. water treatment tablets, so if you’re considering a one-off trek or short journey, tablets would make far more economic sense.

But if you are going to be travelling for a long period of time or know that you’re going to be doing a lot of treks, investing in another method is probably worth it.

For me, with the Mongol Rally around the corner, investing in a method which will provide clean drinking water for a couple of months made sense and I’m happy with the performance, effectiveness and simplicity of the two solutions I purchased.

SteriPEN: http://www.steripen.com/classic/

Drink Safe Systems: http://www.drinksafe-systems.co.uk/

2 thoughts on “Review: Water purification methods- Filter vs. UV vs. Tablets”

  1. I’m sold too! I just ordered myself a Aquaguard Micro 3-in-1 Filter. SteriPEN Classic looks good too. Gonna head to Mountain Design shop in Chatswood later to check it out.

    Thanks for the reviews 😀

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