On Thursday we rose with the sun and headed out to the surface water treatment site to see if we could get the system to produce clean water. A day earlier, the pumps at the Bamtiko borehole — the main source of water for Jamam refugee camp — had failed. The NGO that was responsible for water supply in the camp had made an urgent request to MSF to set up emergency water treatment capacity. Waterborne disease had always been one of the primary threats for the refugee population in this place, but with hepatitis E now also spreading in the camp, ensuring safe water supply was more critical than ever. MSF agreed to do what we could to fill the gap.
My team and I had brought the six crates of the water treatment system to the field the day before and set it up, but I still couldn’t get it working right.
The water treatment system is an assisted direct pressure filtration unit featuring three stages of treatment:
- In-line flocculation – a water treatment process by which suspended particles in the water clump together to become larger so that they can more quickly sediment or be filtered out.
- Filtration
- Chlorination
Water filtration set-up © Imran Ali
The system is designed to treat water with turbidity – cloudiness or haziness of water – up to 200 NTU with spikes of 300 NTU (Nephelometric Turbidity Units – a measure of the cloudiness or haziness of a water sample caused by suspended solids) but the turbidity in the kheffir* we were trying to treat was much higher, around 350 NTU. It seemed to be more than the system could handle and the water coming out was still too dirty to effectively disinfect with chlorine.
That morning, as the rains came in and lightning touched the earth around us, I tried experimenting with different system arrangements, coagulant doses, flow rates and water pressures — anything to make it go, but it still wasn’t working. I was nearing wits end when Eve arrived with the tanker coordinator from the water supply NGO; the taps in the camp had run dry. We needed water as soon as possible.
Line 1 backwash © Imran Ali
Quickly, we moved to disconnect the water treatment system and begin just batch flocculation and chlorination (a simplified emergency water treatment method) in the 30,000 litre tanks that we’d already set up, to get water of some kind of quality out to the camp. We dosed aluminum sulphate coagulant (a chemical agent that accelerates the agglomeration of suspended solids in the water) directly into the tanks and stirred it with a broken shovel that we found. The water began to flocculate immediately but it was still settling too slowly. The water supply NGO had in fact tried batch flocculation at this site before but they found that it took more than six hours settling time to get the water below 5 NTU, what it needed to be for effective chlorination. We didn’t have that kind of time; the camp needed water, and lots of it, right now. After two hours, the water in the tanks was still more than 30 NTU. It struck me that it was likely the high turbidity of the raw kheffir water that was exceeding the treatment system’s in-line flocculation capacity; if we could somehow clarify the raw water just a little bit before the filtration stage, it just might work.
Moving quickly, we disconnected the in-line flocculation apparatus from the treatment unit and shifted the system intake from the kheffir to the tanks in which the water had already been settling. We powered up the pumps, and there we had it — beautifully clear water of 2 or 3 NTU. The tanker coordinator radioed for his water tankers, and we spent the rest of that day pumping clean water directly into the trucks, batch chlorinating them, and sending them into the camp.
Clean water, dirty water © Imran Ali
Every day since then, the system has been producing more than 120,000 litres of safe water for the camp, about half of the total need. We’ve just handed it over to the water supply NGO who’ll be operating it until a newly-constructed pipeline to the Bamtiko borehole has been stabilized.
Clean water © Imran Ali
It’d been good fun getting that system going. By the time evening came around that first wet day, I was covered in mud, exhausted, hungry, my clothes bleached by spilled chlorine — a day well-lived. I’m looking forward to doing it again.
*A kheffir is a small surface water body where rain collects during the rainy season, that people use as a source of household water.
Good job imran. Coagulation and Flocculation is considered one of the approved and effective means of filteration. Every one started to believe the importance of water. I totally appreciate your efforts for the deprived.
News
Clean water for all
THE UNIVERSITY OF WAIKATO
THURSDAY, 25 OCTOBER 2012
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New technology developed in New Zealand cleans and disinfects bore water, making it safe to drink. The new system called PEFT (perforated electric flow through) could be used in developing nations to provide people with clean and affordable water.
Image: trout55/iStockphoto
Two chemists from the University of Waikato have come up with an innovative method for treating bore water on Waikato farms.
They’re currently trialling the system on a Waikato farm and may have hit upon a low-cost solution for developing countries, where many people have limited access to clean and affordable water.
Using electrochemistry Associate Professor Alan Langdon and post-doctoral researcher Dr Hilary Nath decided to try using electrochemistry to remove the iron and manganese prevalent in bore water from Waikato’s peaty soils.
The residues give the water its typical browny-orange colour, and generally make it undrinkable without expensive treatment using aerators, filters, ion exchangers and tanks.
The researchers came up with a simple system that uses electric current passing between two perforated titanium electrodes to turn naturally occurring chloride ions in the water into chlorine.
The chlorine then oxidises and precipitates out the metal contaminants, and also disinfects the water passing through the system, making it safe to drink.
Best of all, the whole system can be powered by a car battery.
“By bringing the electrodes closer together than anyone else has been able to we can reduce electrical resistance and consume less power,” says Dr Nath. “And because the flow path through the cell is very short, we can achieve good water flow at modest pressure.”
The system is known as PEFT – perforated electric flow through – and is patented in New Zealand with international patents filed. A prototype will be on show at the University of Waikato stand at Equidays next month; the university is a strategic partner of Equidays which runs from 2-4 November, 2012.
Langdon and Nath are now testing the prototype, and getting good results – they’ve seen total oxidation of iron during their trial.
“The initial focus will be disinfection of harvested rain water, disinfection of water supplies derived from surface water and bore water contaminated with iron – we need to be very sure our technology is robust before contemplating overseas markets, particularly in developing nations.”
The researchers noticed that the closer together the two electrodes were positioned, the higher the electric field generated between them. And the higher the electric field, the more potent the chlorine being produced.
The two together were so powerful they could kill bugs in the water at much lower chlorine levels than normally required – the electric field was able to puncture the membrane of a bug making it 100 times more susceptible to the disinfecting effect of the chlorine.
At slightly higher applied voltages the PEFT cell can also disinfect water by the electric field alone, with no need to produce any chlorine.
“It’s low technology, but it’s very clever nevertheless,” says Dr Langdon.
WaikatoLink, the University of Waikato’s commercialisation arm, is helping with the commercialisation of the technology. The Kiwi Innovation Network (KiwiNet) – a collaboration focused on research commercialisation – is also providing support as well as investment from the Ministry of Science and Innovation’s PreSeed Accelerator Fund (PSAF).]
Please check this site for info:
http://www.sciencealert.com.au/news/20122510-23819.html
Helle Imran bro…
You have done a great work indeed !
One of the biggest concerns for our water-based resources in the future is the sustainability of the current and even future water resource allocation. As water becomes more scarce the importance of how it is managed grows vastly. Finding a balance between what is needed by humans and what is needed in the environment is an important step in the sustainability of water resources. Attempts to create sustainable freshwater systems have been seen on a national level in countries such as Australia and South Africa, and such commitment to the environment could set a model for the rest of the world.
The field of water resources management will have to continue to adapt to the current and future issues facing the allocation of water. With the growing uncertainties of global climate change and the long term impacts of management actions,the decision-making will be even more difficult. It is likely that ongoing climate change will lead to situations that have not been encountered. As a result new management strategies will have to be implemented in order to avoid setbacks in the allocation of water resources.
We are also doing a lot in Water Resource Management. Our Technical expertise is used in an International Water Management Week i.e. India Water Week 2013 : Efficient Management of water: Challenges and Opportunities. For more detail you can visit http://www.indiawaterweek.in
Imran you have made important technical contributions to your field and done a commendable job. We all are proud of you ! !!
Cheers ! ! !
Suhail
Hi everyone, many thanks for the kind comments and questions! It’s really encouraging to get that kinda feedback while out here in the field. Lemme take a quick moment to try to respond to some of the q’s posed by Greg:
One of the main constraints out here in Jamam is the region’s inaccessibility during the rainy season. It seems to be ending now, but for the past several months most of the dirt track roads in the region have been totally impassable, especially for heavy vehicles. As a result, almost everything has to be flown in — from food, to medical supplies, to water treatment units, all the way to chairs for people to sit on in the clinic. This, coupled with the hyperinflation that has struck South Sudan since oil production was suspended last year over conflict with Sudan regarding pipeline transit fees, has made the cost of bringing in material extremely prohibitive. As such, we have to do the best with what we have available and can realistically obtain, instead of what might be ideal. The water treatment system we had on hand (the three-stage system that I describe in the blog) is a tried, tested, and true strategy for emergency water supply. The system is actually an in-house MSF design, developed by the Belgian section of MSF. As we found here, with some simple system modifications, it is adaptable to, and effective with, most surface water sources.
Regarding coagulation — it actually began immediately once we had dosed the alum via the suction side doser. You could see the flocs forming as soon as the water was pumped into the 30,000 L settlement tanks. What took a long time was allowing the flocs to settle out. The influent water was around 350 NTU, and after half an hour of settlement, it was down to about 50 NTU. It took about one to two hours to get it to 30 NTU, at which point we ran it through the filtration phase. We did find that the settlement tanks we left at the end of the day were very clear the next morning, under 5 NTU, but that took 6+ hours of settling time to get water that clear, which was too long for the production rate we had to achieve. We had some limited quantities of iron chloride available, but I preferred to use alum in this case, as it is generally easier to obtain.
I hope this helps answer some of your questions!
Absolutely fantastic work that you are doing.
Awesome Imran- I just sent this on to a much of folks. Hope our paths cross again one day soon! Keep the updates coming. You write well… Which I’m sure others have told you. We need more Engineers / scientists who have that dual capacity
I am so proud of such great minds that scatch to provide solutions to the disadvantaged humanity…. This is a lesson learnt, sir. I am a logistician who has alot of interest in water and sanitation. You and your teams efforts have hardened my resolve. Thanks for saving lives and providing the water department with an opprotunity to improve. Kudos.
Is there a reason a staged system couldn’t be used? Perhaps a silica filter followed by membranes? I know pool filters using sand are pretty effective on their own and with minimal backflushing can operate for several million liters.
Do you know why the coagulation took so long? In my experience with it, all it takes is a few seconds to start precipitating out. Are there other substances available to you? Iron chloride?
That’s engineering at the sharp end, saving lives where engineering skills make the difference. Great job Imran – well written too!
Thank you for posting this! I am getting ready for an assignment, and just read the chapter in “Engineering for Emergencies” on water treatment options. I hope my site has an engineer as nimble and persistent as you!
Funny, reading the blog, it was immediately clear to me that it was the high turbidity of the intake water that was the issue. But of course, I knew this because you’d already figured it out, and there was foreshadowing in your blog post. As a troubleshooter myself, I know how hard it can be to have that moment of insight. Great work troubleshooting the issue, and helping to save lives!
Great work indeed! keep it up, you guys have served the community! I’m proud of you.
Hi Imran –
Great work you’re doing! For a new nonfiction anthology, The Places We’ve Been: Field Reports from Travelers Under 35, we are currently looking for submissions and would love to invite you to take a look and consider if you might like to participate. A bit of info from the general call for submissions is available at http://www.facebook.com/ThePlaces35. The deadline is stated as October 15, but we have a special invitation/extension through November 15 for invited bloggers.
Thanks for your consideration, and feel free to be in touch for more information!
Asha
Great work (and pictures), Imran!