Supplying clean drinking water to the Rajarata in Sri Lanka.
Posted on July 8th, 2015

By Bodhi Dhanapala, Quebec, Canada

The north-central province (NCP) in Sri  Lanka, encompassing much of the ancient Rajarata with its irrigation channels and tanks (weva),  has been afflicted with a kidney disease that was first identified by Nephrologists circa 1992. These patients were not linked with such well-understood causes like having diabetes or hypertension. The disease was named chronic kidney disease of unknown aetiology (CKDU). Also, although the first cases appeared in the early nineties, its causes must have existed before, as the illness develops slowly. This threw back the roots of the illness to the debut of the Mahaweli project, i.e., the  late 1970s. This period, and the earlier decade (following the eradication of Malaria) saw a rapid rise  in population in this  fragile dry-zone environment. The disease may even have existed in earlier times without being recognized.

Theories about the cause of CKDU.

A comprehensive study of the illness was sponsored by the  WHO and the NSF. It  examined the  recognized  causes like  toxic heavy metal pollutants like arsenic (As), cadmium (Cd), lead (Pb) etc., as well as pesticide residues, gender and life-styles.  The WHO-study showed clearly that  arsenic and other metal”  toxins, or pesticide residues like glyphosate were NOT  present in the NCP water or the soil.

Theories based on arsenic and other toxins had to be ruled out as several independent research groups (from Peradeniya, and from Japan etc.) confirmed the WHO-conclusion that  metal toxins are absent even at the astonishingly low  10 parts per billion level in the Rajarata water. However, a very small number of researchers like Dr. Jayasumana of the Rajarata University have adamantly maintained that arsenic enters into the body combined with glyphosate,  and causes CKDU, even though neither arsenic, not glyophosate is found in the Rajarata water table. The  arsenic people”  have the support of  credulous religious activists who claim that even divine spirits have confirmed that CKDU arises from  arsenic!  Their vociferous, short-sighted approach to combating CKDU has been to call for  a rapid ban on herbicides and fertilizers. In Sri Lanka.  Politicians propelled by uninformed journalists who fan public fear have recently banned glyphosate, throwing the plantation sector into jeopardy. This action is similar to that of persons  who take preventive medication” against some disease even though  blood tests show that they do not have the disease!

Arsenic was detected in the WHO study in the hair and body organs of CKDU patients. According to a study by Nanayakkara et al., jointly with Tokyo university, the  type of arsenic found in CKDU patients is identifiable with that found in dried fish. Healthy people reject such arsenic, but those with damaged kidneys bio-accumulate the arsenic and show up in bio-assays. Thus the arsenic accumulation is a result of bad kidneys rather than an initial cause.

Focus on clean water.

Rajarata residents who consumed spring water, municipal piped water  or flowing surface water (in rivers and tanks) are relatively free of CKDU . This prompted several researches to consider that the illness must be linked to drinking water,  since the metals, herbicides, and other  multi-factorial” causes  (like life-style, poor agro-chemical safety practices etc) cannot be the culprit” since the first two are absent, while the life-styles and agro-chemical usage of these farmers are common to all (a multi-factorial set of all the usual causes has been claimed by Prof. Wimalawansa).

This led to various proposals for the c ause of the disease, one of which  is that the high ionicity (excessively high levels of certain salts which affect protein layers in the kidney) could be the cause of CKDU. This has the merit of not needing arsenic, Cd, or glyphosate as  the causative agent, given that they  are in fact NOT  found in the Rajarata water at any significant levels. Irrespective of whether this ionicity idea (Prof. Dhamawardana et al) , and related ideas based on fluoride ions (Prof. Illeperuma et al)   etc., are  correct or not, it is evident that the supply of clean water  should be a very desirable step in eliminating CKDU. It has also been ascertained that the  water in ground wells (rather than from rivers and tanks)  have high electrical conductivities,  showing that they have a lot of salts and a high ionicity, while not containing arsenic or glyphosate.

How to provide clean water to NCP residents.

The above discussion  suggests that it is  desirable to use the water from rivers and tanks, and treat them at home or in community locations to bring the water to municipal standards,  using simple low-cost methods which are appropriate for the  affected rural villages  of the Rajarata.  Meanwhile, a number of NGOs have promoted the technology known as reverse osmosis” (RO), where the contaminated water is forced through special membranes using high pressure pumps. The membranes allow clean water to pass through, retaining the salts and contaminants behind.  This provides a high-tech turn-key” solution, providing fully de-mineralized water. This technology is not cheap, even for affluent communities.  However, RO is the only adequate method if the untreated water is salty. Water containing over 3.0 grams/litre of salt is salty. Completely demineralized water (RO water) is normally  remineralized  to bring its hardness to about 200 mg of Ca-equivalents/Liter to make the water palatable. It should also be  chlorinated  (as with municipal water) to ensure that no accidental bacterial contamination occurs. Many, but not all scientists,  believe that such mineralization helps to reduce cardio-vascular diseases (see, e,g., the Wikipedia article on hardness). The proposal to put back a bit of the RO waste water to remineralize the RO water may be adequate for livestock, but certainly not for human consumption.

However, very low-tech, extremely cheap methods are available for  obtaining clean water from polluted fresh water where the remove of NaCl and full de-meneralization are not needed. Since the NCP waters are not high in  NaCl  (c.f.,Table I of Water Lanka, vol. 3, issue 3), we discuss two possible water-cleaning devices which are, in our opinion, adequate  as they can deal with fluoride and many other toxins. The first is a simple domestic  filter that can be assembled at home,  which uses clean sand and granulated bleach (calcium hypochlorite),  and optionally some activated charcoal.  A family would need a bag of  fine clean sand, and a small drum of calcium hypochlorite granules from a swimming-pool supplier. To last 3-4 months.  About 25 liters (i.e., about 5 imperial gallons) of water are brought from a stream or  tank (weva”)  each day and provide the drinking and cooking water for a family of five. This water is stored in a glass fish-tank” and  treated with about one spoon of swimming-pool grade granulated bleach. The chlorine in the bleach destroys the bacteria, algae, organic matter etc.. The resulting broken-down debris  flocculate  and sink to the bottom of the tank.  Furthermore, the calcium hydroxide and calcium carbonate present in the bleach granules react with any fluorides, phosphates, (or arsenates)  and precipitate them  as insoluble calcium salts which are brought down with the rest of the debris. These processes work best when the pH of the water is maintained near 7.  Even if some of this material remain as suspended matter, they are removed by the next stage where the water passes through a sand filter. The sand is held in a cloth bag lining the container and thrown out every two or three  days.

The water may be (optionally)  brought into contact with (a cloth bag containing) activated charcoal (made at  home from coconut shells, or purchased), and  further  refiltered (sand bed).  The sand from the last stage can be used in the first stage to economize on sand.  A method of making home-made” activated charcoal from coconut shells, developed by  scientists at  Santa Clara University, California, USA  may be found at

I also contacted a municipal water-works engineer in Quebec, Canada who suggested that commonly available swimming pool filtration technology can be used to construct filtration units that may be used to at least pre-treat (or fully treat) river water or  weva”  water. It is easy to set up a 10, 000 gallon above-ground plastic pool and use it as the water container or storage tank. It is  filled, when needed,  from a stream containing contaminated water. The pool-tank” is treated with the appropriate amount of calcium hypochlorite  (determined using a drop of indicator in a test tube, available from pool supply stores  to optimize  the amount of bleach used), and the chlorine is allowed to act on the water. Once the algae, organic matter, and insoluble calcium salts have precipitated down (usually 24-48  hours), the pump is turned on. This circulates the water thorough a  sand-filtering system. As the sand gets clogged with the filtered debris, the pressure builds up. At that point a back-wash step is carried out to wash away the contamination and the filter is rejuvenated. This process is carried out till the water is clean, or using test papers and indicator solutions giving the pH, total solids, total chlorine etc. The back-washing process leads to a loss of about 10% of the good water produced by the unit.  RO membranes also needs regular back-washing, and also looses a significant amount of the input water as the RO-waste water is  unusable.

The chlorination and filtration presented here will purify the water but it will not reduce the hardness of the water. However, as mentioned before, the hardness data seen in Table I of the Walter Lanka, vol. 3 reference given earlier suggest that river and tank waters in the Rajarata are hard but quite palatable. In any case, it is very easy to determined that the output water (collected in the pool tank”) is palatable by drinking a bit of it. A detailed chemical assay (as done for municipal water) should be conducted as frequently as possible.

Notice that we have not used activated charcoal in this pool-tank filter system. We feel that maintaining  the stipulated amount of chlorine. Health  guidelines state that The use of chlorine in the treatment of drinking water has virtually eliminated water borne diseases, because chlorine can kill or inactivate most micro-organisms commonly found in water. All drinking water supplies should be disinfected, unless specifically exempted by the responsible authority. …The health risks associated with disinfection byproducts are much less than the risks from consuming water that has not been adequately disinfected. Free chlorine concentrations in most Canadian drinking water distribution systems range from 0.04 to 2.0 mg/L.”

The water delivered from a simple sand- filtration and chlorination system will run at a tiny fraction of the cost of high-tech RO plants, and will require minimal intervention. The sand in sand filters need not be replaced for several years. The filtration units for a 10,000 gallon installation would be less than $150! The chemicals, equipment and know-how needed for  a pool-filtration type water system should be freely available in Sri Lanka because tourists hotels and resorts routine maintain swimming pools.

It is sometimes suggested that the chlorine in the water should be removed and that its presence is mildly  objectionable. However, the Walkerton tragedy, where accidental contamination at the output stage (this led to the death of 7 people and hospitalization of thousands) was due to lack of adequate chlorination. Water from RO plants and other large distribution units should also include a chlorination step.

An important question that can be raised here is, what evidence do we have that this type of treatment of water is sufficient to eliminate CKDU? The main evidence we have is the fact that  Anuradhapura municipality is NOT a CKDU- stricken locality. The municipal water used in Anuradhapura does not completely de-mineralize the water as is done in RO plants. While the methods used bu municipalities are more elaborate than what is described here, the filtered water obtained by the simple methods used here should produce a water similar to municipal water, and far more healthy than the highly contaminated  water from grond wells consumed by residents in CKDU- affected areas.

ITI scientists have also proposed water-filtration systems using a clay-filtration tablet.  The tablets can be discarded when they get clogged, as back-wash may not be possible, unlike with a sand-filtration system. Chlorination and means to remove fluorides, phosphates etc., are not included in the ITI system.

Collection of rain water has also been discussed by many people, and this should also be encouraged by supplying inexpensive water tanks to the people in the affected areas.

In conclusion, we have explored a number of very simple and inexpensive water filtration devices that may be useful to rural people, and well within their technological and financial capacity.  The high-tech RO units belong to another level of sophistication and the two technologies are complementary. The rationale for proposing such simple units is that many of the causative factors originally proposed for CKDU can now be ruled out. For instance, metal toxins,  glyphosate,  agro-chemical  misuse, or poor lifestyles cannot be relevant since these are equivalent for people in a village using spring water and not contracting CKDU, or for people in an adjacent village who do not use spring water and end up with CKDU.  Metal toxins, herbicides or chloro-carbons  etc., are not detected even at 10 parts per billion levels and hence attempting to remove them is pointless. The simple methods proposed here do not require a re-mineralization process to make the water more palatable and more healthy. They automatically incorporate a chlorination step which is mandatory for  community water distribution systems. Furthermore, these simple filtration systems can be set up using local technological competence.

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