Ultraviolet treatment for rural water supply

Published on by in Case Studies

We want to start a demonstration project about the capabilities of Water UV treatment to small communities, where sodium hydrochloride is difficult to transport and regulate. We are interested to learn for existing examples and similar experiences on small villages.

We're studying the possibility to utilize systems of disinfection with ultraviolet at the supply of water for these small rural populaces, with sudden changes of populace, many of them have little populace in the winter, that augments of sudden form in the summer or at determinate seasons.

We are interested to learn examples about the application of this technology, at small villages around the globe, and its effects, specially to know problems that we should preview and how to resolve them. Transport hypochlorite until the supply deposits  is not easy but I know that it will be necessary to dose punctual disinfectant quantities. It may be simpler that the constant and continued  dosages when water demands varies suddenly because of the reduced resident population.

Thanks

Taxonomy

14 Answers

  1. Good idea for electrified rural habitats.

  2. Dear Eduardo,

    The Plasma Water Sanitation System is an interesting technology. Please see:  http://az-foundation.org/question-answer-plasma-water-sanitation-system/

    Regards.

    Rafael

    1 Comment

    1. Dear Rafael,

      Sounds good, but I have no technical or scientific information about this process to analyse, I'm sorry.

      Could you, or your colleagues, sent me more detailed information.

      Best Regards,

      Eduardo (emg@comei.es)

      1 Comment reply

  3. Dear Eduardo,

    I fully agree with the points raised by Joseph Cotruvo,

    From my personal experiences, I would not go with using UV for disinfection of rural waters, its expensive and required professional work to operate and maintain, I assume you cold look for another cost-effective alternative

    It would be good if you can analyze the raw water to identify the man constituents, and based on that we can suggest another treatment options rather than UV technology

    I might suggest to use available natural materials from the project area such as natural coal/ sand Coal mixed in fixed bed form. Such beds will help in reducing nuisance odors/ irons, other dissolved solids and also microbiology from the raw water. The effluent from the fixed bed system can be disinfectant using any other proposed technology like chlorine, or UV . if this might be good option, please contact me and we will discuss further (zrashdan@yahoo.com)

    Best wishes

    Zaid

    2 Comments

    1. I agree with you, but using filter bed before applying uv or other disinfection tech will help in reducing costs of the UV system 

      If you already have some analysis for the raw water please share it with us so we can assist him in better way

      1 Comment reply

      1. Yes, I agree. That's why we keep in mind the possibility to incorporate sand filters (to reduce turbidity) and chlorine pulses or reduced continuous injection.

        Thanks

    2. Filters are useful to separate particles as smaller than clay, protozoa, and maybe some bacteria, but has no effect to all bacteria and viruses, where disinfectant chemicals (or radiation) are needed, that's why we are looking for alternatives to.

      Thanks for your opinion.

  4. Dear Eduardo

    I will not tell you that UV is not an appropriate solution for rural place but keep in mind that additional water transport is a practice for users. An additional advantage is to consider the remanance of chlorine

    If you have few minute i invite to to have a look on our Non electric Dosing pump DOSATRON Water line . it might help you to find appropriate solutions.

    And i fully agree , Naclo generator in situ can be a good solution . Salt is available everywhere  . Look after WATA technology

    I am at your full disposal

    Christophe

    2 Comments

    1. Thanks!!
      I didn't know this kind of pumps... do you have a distributor in Spain? if you want, they can e-mail me to emg@comei.es or call to +34 933 134 666

    2. What we are trying to avoid is to add chemicals to water and reduce wastes. Salt, and packaging, is another problem when people "thinks" that they drink the "best" water of world... (but it's necessary to treat against micros)    

       

       

      1 Comment reply

  5. Hi Eduardo.  Sounds like a great project.  I cannot help you with UV, but we do have a small ozone module that generates ozone from the water, so no chemicals are required. We have already used it to replace sodium hypochlorite in small and medium-scale disinfection applications.  You can recirculate the ozone in the storage tank so that when you need water, it will be free from pathogens at the point of use.  It runs off a 12V power supply.  Good luck, and if you are interested, just let me know.  Peter

    1 Comment

    1. Hi Peter Barratt , sounds good.
      Ozone was a first proposal to treat water but I thought that local generation will be energy costly. Ozone has some residual effect that can't offer UV treatment, and when is combined with in water degrades to oxygen...

      Could you send me more information about?

      Thanks!

      1 Comment reply

  6. Hello. UV disinfection is used quite widely in Central Asia / former Soviet Union, especially for ground water which is generally (assumed?) to be high quality. Even basic systems seem quite effective (when bulbs are new and system is switched on an maintained!)  and due to remoteness of some villages, it is preferred to transport of chlorine products. Environmental concerns also discourage low quality powder which results in a lot or residue which is sometimes just cast aside. As others have said, the biggest issue is the lack of downstream protection. For new systems or those in good condition this is perhaps less of a consideration, but mostly the systems are old (often AC pipe or similar) and storage is not well maintained or monitored. For this reason we mostly discourage UV if chlorination is an option and only advise for fairly clean (particle free) ground water. 

    1 Comment

    1. I agree with you. The main UV advantages seems water taste, waste minimization and periodic transports of chemicals. At the other side we are considering reposition and energy costs and the main problem with residual effect.

      Is possible that chlorine, or another disinfectant, must be injected to pipes to maintain a residual effect. The question should be if disinfection must be done continuously or a batch treatment is enough.

      Any experience about?

      Thanks

  7. Dear Eduardo, UV works quite good for disinfection, although you should consume the water betweeen 12 and 24 h later so try to size small volume storage tank.

    For increasing the efectiveness, it´s high important to filter the water up to 5 - 10 micron. Bigger particles could produce ``shadow effect´´, increasing the pathogens after UV.

    About the number of lamps, you will have to size for the worst situation.

    Best regards,

    Pablo

    1 Comment

    1. We are studying its applicability with water with less than 0,5 NTU, to avoid this shadow effect, as we know that is ha handicap to treatment effectivity. Only spring or well water sources should be used, because UF o extra filtration should be costly.

      Thanks!

  8. Hi Eduardo,

    AS UV has no residual disinfection downstream capabilities, all UV units would need to be point of use for each tap to comply with WHO and other regulatory guidelines for potable drinking water,  multiple small UV's would need to be considered.   

    Basic alarms, clearly defined service intervals and maintenance over time is important as poor UV transmissivity, or non functioning lamps provide risk of pathogenic microorganisms infecting the people.  

    Calcium chlorine tablet dosing systems  are cheap low tech that could be considered  and residual chlorine can be measured with low cost dip strips.   

    A fundamental that must be considered is very low turbidity ( very clear water) is required for UV to not have particles shielding the virus, protozea, e-coli etc.   Ultrafiltration units that only require 2 m head to operate are the best way to ensure clean potable water.  Then any residual disinfection, or UV is a secondary precaution, not the key disinfecting technology.  

    It is very cost and best practice effective to use an absolute barrier to microorganisms and colloidal sub micron particles such as gravity fed ultrafiltration (UF) system upstream of any UV or chlorine dosing.   

    This ensures very low risk of transmission of water borne diseases despite less than ideal maintenance occurring.    You are welcome to get in touch if you require a price estimate.   Best wishes for your project.  Cheers Mark      

    1 Comment

    1. UF and UV combination sounds interesting but add more complexity to the system. At this stage we are looking to treat only well and spring water, that we assume has no turbulence.

      Your experience is very valuable.

  9. I'm aware that UV has been used in the past (1990's) in two small central Australian communities (pop <100) where there was strong community resistance to chlorine dosing but I expect that the hurdles to UV are higher now and alternatives might be better.

    Do you have a study design, evaluation criteria, risk assessment, community engagement plan etc' for this proposed demonstration project?  Address also the ethical aspects of experimenting on a community! 

    Some specific factors to consider:

    • fire flows - often even in small rural systems there are hydrants used for flushing and for firefighting which can cause very rapid increases in the flow rate. You need to be able to treat that full flow;
    • detention time in the network, from UV to outlet.  UV is great for point of use where the lamps are always on and the flow is pretty constant. As a rule of thumb, the detention time to the tap, NOT to the meter, should be less than 2 hours.
    • lamp warm up time - how do you propose to manage the required delay for the UV lamps to warm up before disinfection is effective?
    • network depressurisation & maintenance downstream of UV.  Disinfection is required if there is any loss of network containment or pressure arising from operation, maintenance, repairs, new connections and network extensions.
    • Operator risks - I've known technicians to override the UV lamp cut out safety switch when doing inspections and maintenance to "check that the lamps are working" and then suffer eye damage. You'll need to address "safety in design" aspects. 

    UV disinfection has an important role and I like the technology, but in this application I suspect that, at best, it should be used in conjunction with technology that provides a  residual disinfectant.

    Regards, Harry

  10. I don't think this is a great idea. UV is much more expensive and requires maintenance, lamp replacement, electric power, degrades over time, and leaves no residual disinfectant. Chlorine bleach is cheap and effective and leaves an effective residual for transport to the consumer. The positive for UV is that it is better for protozoa like crypto or giardia. Is it easier to locate and purchase/pay for and transport the UV systems, than to obtain chlorine? Chlorine can be made on site from salt.

  11. Good Afternoon Eduardo,

    UV efficiencies are dependent on system design for flow proximity to radiation, internal refraction, chamber contact time, source water turbidity, hardness and iron content...and equally important, constant uninterrupted electricity.

    Aquathin uses a UV system with ozone generating bulb.  We also integrate the AquaShield Anti-Microbial Filter as a failsafe.

    The AquaShield is used for over 15 years in Sub Saharan regions where electricity does not exist.  You may know of the Roundabout Company, that produces a well pump within a playground merry-go-round.  When children play on the roundabout, it pumps water from a borehole into jojo cisterns through the AquaShield to filter and destroy bacterial including cholera.  See attached document.   Also visit Aquathin South Africa website for their "Rural" system which is a "pour through" utilizing AquaShield. www.aquathin.co.za 

    Feel free to contact if we may be of further service.

    Warmest regards,

     

     

    FOR THE BEST TASTE IN LIFE

    Celebrating 40  Years Pure Excellence

    ...into another Half Century re-inventing the water industry !

    Think Aquathin...AquathinK !

    ( visit the all new www.aquathin.com )

     

    ** AN ISO9001:2000, ISO9001:2008 , ISO9001:2015  QMS REGISTERED / CERTIFIED COMPANY - (IMS 0192, NQA 12635) **

    & 2008 PRESIDENT'S E STAR AWARD RECIPIENT ( visit www.aquathin.com/estar2008.pps  )

     

            Alfie

    Alfred J. Lipshultz

    President & CEO

    Aquathin Business Center  /  950 South Andrews Avenue / Pompano Beach, FL  33069

    T 954 781 7777 / F 954 781 7336 /E info@aquathin.com  / Skype aquathinhq.alfie

     

     

     

  12. UV is a very effective disinfectant, provided that  UV units are properly sized and maintained. However, I have concerns about using it for small communities for these  reasons: (1) no residual disinfection is provided by UV. Thus, chlorine (in smaller doses) will still be needed if there is a distribution system; (2) UV lamps require periodic replacement and are also subject to failure before their theoretical lifetime expires. (3) UV units may be damaged by voltage fluctuations which may occur in remote areas. Lamps are not readily available, while chlorine disinfectants. particularly NaOCl  and CaOCl are much easier to find. Have you considered on-site hypochlorite generation from a salt-water solution?

    1 Comment

    1. Thanks,
      smaller chlorine doses is an option to keep net clean, but I don't know if somebody has experience about periodically bluff of chlorine to disinfect distribution pipes, what will be the best alternative?
      I propose frequently microbiological tests to check treatment quality.

      Local government are looking for an easy treatment that evicts product transportation and water taste to the supply tanks, and also no residues, that's why sodium or calcium hypochlorite is not an option (because NaOCl is in use nowadays)

  13. Hi There

    We have technology available that is South African developed and patented.

    It is perfectly suited to small rural habitats that generally do not have the power needed to run RO and UV tech. 

    If you are interested to know more, please email hugh@cybercom.co.za or call +27 (0) 721422501

    Kind regards

    Hugh Ingpem

    0721422501

    Water 4 All

  14. My experience from an engineering side is limited, but from a social and acceptance side, please be advised that a strong community engagement and education programme may be necessary. In rural Tanzania, I encountered a very nice UV disinfection programme for small rural communities. However, no awareness raising was undertaken. As such, none of the community would drink/trust the water that was UV disinfected, and instead, only drank unsafe water from shallow dug wells. (The male community members believed it would make them sterile.) Good luck with your research.

    Answered on by

    1 Comment

    1. Thanks,
      Our work will be done at rural European communities where people don't like the chlorine taste and are curious and interested about any economic and tasteless solution with no residues.

      Your experience is very interesting because it demonstrates the importance of society education and prior implication on proposed solutions. Explain the project and convince people is necessary to project success, of course!