Groundwater Quality - Health Safety

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A significant number of boreholes in Harare, Zimbabwe have been contaminated mostly by E. Coli according to tests carried out by the City council recently. Besides, cholera and typhoid cases have been reported and health officials have attributed this to poor water quality.

Is there any adaptation and mitigation tools that can be adapted to resolve this problem? Most domestic users do not have any kind of water treatment system. 

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21 Answers

  1. Contamination likely occurs due to percolation of sewage into underground water. Even if the well is disinfected the recurrence of contamination cannot be ruled out. Best method will be boiling of water & storing in the copper vessel. Copper acts as disinfectant. Storing the Water in Copper pot for overnight also disinfect the water. I can share more information with you.  Please write me on sarafrv@virajenvirozing.com

    Prof. Rajendrakumar V Saraf

    1 Comment

  2. Hi Tendai, yes there are is the short answer, unfortunately, and as you probably know, it is not that simple as regional/point source contamination is likely, presenting various degrees of water quality requiring various applications of treatment to render the water safe for consumption.

    There are technologies and products readily available and I am steering service delivery agents in Harare on similar approaches, we can be engaged on for further information gathering and application or roll out of solutions.

    Please contact me if you would like to explore mutual collaboration

    Regards

    Gary

  3. Are these boreholes or encases wells or springs? It is necessary to locate the sources of contamination and fix them. But in the short term it is essential to disinfect the wells. It is the simplest quickest and least expensive way to respond.  The standard technique for disinfecting wells is to add the appropriate amount of chlorine (as hypochlorite) to flush the system, and monitor regularly to determine whether the contamination has returned. See the American Water Works Association standards for new wells and well rehabilitation.

  4. Thanks for the information.  Please note that TAM Ceramics, Niagara Falls, NY USA, is readying distribution of water filter media of granulated ceramics, for large scale, community sized-water filters.  Do have a look at the website:  https://tzenvirohealth.wixsite.com/tamfiltermedia2

  5. Hi Tendai

    In a case like this where you might need a inexpensive and easily implementable fix to remediate the water coming from the boreholes. I would probably suggest treating the water with some intermediate tanks, dosing of the appropriate microbes and an aeration/mixing process.

    The microbes can fully remediate the water to an (more than) acceptable standard with minimal maintenance to the remediation systems.

    Now the issue stopping this contamination will need to be investigated so that the source can be identified and the water protected.

    I work for a company with some insight into such problems and we are based in Pretoria, South Africa; a stones' throw away. Please feel free to send me an email at francoisaleroux@gmail.com if you want some information or input.

    Regards

  7. Deanna Dunseith  I think if animals are the cause than there will be an increase in nitrates.

    Tendai H. Madzaramba  E Coli is from Human sewage. If it is a rural area where you sampled then I think lots of unlined septic tanks which are leaking into the groundwater. Sometimes residents even go for very deep septic tanks so that they don't have to empty them quite often and this results in groundwater contamination. Also rainy season may be resulting in carryover of sewage into the groundwater. So I think you should focus more on prevention of groundwater contamination. Simultaneously, boiling of water and chlorine tablets are the best idea. And all this should be done immediately as this is a very serious issue. All the Best!

  8. Hi Tendai,

    It is unfortunate that the water wells seem to have been contaminated by fecal matter from humans or animals resulting from sewage overflows, malfunctioning sewage systems, etc. A through and urgent investigation needs to be done and the hazardous situation remedied to avoid serious waterborne disease outbreak.

    Solutions or expedient measures by households:

    (1). Disinfecting the water with Sodium Hydroxide or any chlorine-containing water treatment disinfectant will help kill the E.coli and other pathogens in the water.

    (2). SaferEx - Multiaction Water Purifier innovation will be very very great in treating the water by households or large scale. SaferEx disinfects, coagulates, sediments and clarifies, removing colour, odour, taste, heavy metals, etc, from the unsafe water in "a single application and unit process". It can be used at homes by mixing in buckets and tanks or in installed water treatment plants by dosing or injection. SaferEx is in available in Botswana and South Africa. Please get more details about SaferEx Technical Date Sheet (TDS) link: https://goo.gl/4Ktqwq.

    Regards.

    Justin.

     

    1 Comment

  9. For my opinion, pls check the source of waste water leak which might be flow down to underground water. For the technology you can use chlorine, UV, Activated carbon. Normally we have never face much  this topic in Thailand and we dig or do the well hole to check around waste water (AD) plant. I have journal which write down of the natural fitration of the soil will make the ground water still clear with good quality with the depth 30-50 for villager and 200 for the Factory which consume 1000-1500m3 per day mix with big canal or big river including rain harvesting.

  12. Well, it is rare case that ground water is contaminated with E.coli, even if it is shallow well. Now , urgently you need to provide treatment basically disinfection. But further investigation will be required to protect the well field from contamination with domestic sewage.

  13. Here is plasma reactor + active carbon filter  for perfect disinfection of all bacteria and removal of heavy metals and arsenic  in the under ground water .. and no chemical, no ozone, no RO,
    simple to use .. physical treatment......  http://bbnworld.net/water/awp15_techdoc.pdf 

    The plasma high voltage pulsed discharge is induced directly in the effluent stream generating multiple oxidants and radicals such as OH, O, H, O3, H2O2, etc.

    Such aggressive oxidant species are nonselective and oxidize all contaminants in the effluent. A high intensity UV light released during the process is used for bacteria disinfection. 

    The price is USD7500 and delivery by FeDex  within a month. bbn@bbnworld.com  Frank Choi

    1 Comment

  14. Hi Tendai,

    As well as the useful posts given so far, you are welcome to consider the use of the community-based ClariWash treatment system - low cost and low maintenance. It is effectively self-build - I attach a leaflet. The filtration using a high-quality media should remove most e.coli and chlorination can be used afterwards to give a free residual.

    Kind regards Nigel Heeler  - WaterReach

    1 Comment

    1. I have a question about the ClariWash ​treatment ​system:  Where this is deployed, for how many years does Clariwash provide maintenance, and at what cost?

  15. as an immediate first step you should consider point of use filtration of the types use by backpackers as these are easy to transport and use and relatively inexpensive. check with aid agencies to see if you can get some funding and other assistance. 

    1 Comment

  16. Hello Tendai, there seem to be several approaches, for me remains still the question how much water you want to treat. If there is a only a minor volume per day (e.g. 100 liters), an simple ultrafiltration filter can solve the issue here. We from Kwatee have used in similar cases a simple filter (combination of ultrafiltration or microfiltration with activated carbon) that can treat 5000 liters of water and costs only 80 EUR. It is a standard 10" filter, the housing is available all over the world (e.g. "the blue filters").

  17. @Tendai

    This is an issue which requires a holistic approach from both stakeholders( end user and service provider). There is need to make sure there is no contaminated water infiltration close to the borehole to prevent contaminating the source groundwater. Secondly there is need to educate the end user (community) to engage in healthy and safety activities regarding cleaning water maintenance. If the service provider and the end user are able to do this, the issue can be minimised, otherwise to totally eradicate the problem there is need of more advanced approaches prior to the supply of borehole water, probably chlorination before being used.

  18. Brumby Pumps aerate the water at the source and can help deal with these bacteria as the water is pumped to the surface. www.brumbypumps.com 

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  19. In addition to using chlorine to disinfecting the water, create an animal free zone around the boreholes. In the US, its typically 150 feet. Runoff from feces can easily contaminate the water, as can "dirty" hands. Education will help with both of those.

  20. I am thinking of chlorine tablets either at source or supplied to households/ households encouraged to use these as a precaution. Biggest challenge in my view is that source of contamination seem to be frequent failure of the sewerage network and unless this is resolved the problem will be recurring.

  21. Hi Tendai, we have similar challenges in some parts of Kenya. I assume when you say boreholes you mean hand dug shallow wells . In Kenya we have situations where chlorine is dosed directly into the well. The chlorine is either in tablet or liquid form, packaged for household use.

    A household can also put chlorine tablets in the storage container which they use for drinking as a form of household water treatment.

    However, for this to be effective, proper training at community level on use of the chlorine is absolutely necessary.

    2 Comments

    1. You do not define borehole, so I am like Rose, thinking you may actually refer to hand-dug wells, which can be contaminated by runoff or nearby septic tanks or animals. I immediate solution would be chlorine (sodium hypochlorite tablets) or ceramic filters in the house. I the longer term, a well-protection scheme is needed to line wells and isolate them from coliform sources by fencing. This is a VERY serious public health concern, which should be brought to the attention to public health authorities in your vicinity. Infected people need to be kept hydrated until they recover. It needs a comprehensive approach to address your problem, and your government must be involved.   David Boggs, PE (water engineer)