Submitted to Journal of Health Population and Nutrition
Revision October 14th 2005
ONE SOLUTION TO THE ARSENIC PROBLEM:
A RETURN TO SURFACE (IMPROVED DUG) WELLS
Sakila Af. Joya, Bivash C. Barmon, Ariful Islam, Golam Mostofa, Altab Elahi, Jabed Yousuf , Golam Mahiuddin#, Mahmuder Rahman, Quazi Quamruzzaman
Dhaka Community Hospital
Wireless Railgate
Dhaka, Bangladesh
Richard Wilson
Department of Physics*
Harvard University
Cambridge, MA 02138, USA
· Address to whom correspondence should be addressed
# Address to whom requests for reprints should be sent
Abstract
The problem of contamination of drinking water in Bangladesh by arsenic is a major catastrophe that dwarfs most other man made disasters. The national policy is to encourage a return to the plentiful surface waters in so far as possible without encountering the problems of sanitation that led to the use of ground water in the first place. In this paper we describe the procedure and the success of the Dhaka Community Hospital team in implementing sanitary, arsenic free, dug wells. The capital cost per person for running water is between $5 and $6 per person. Since it seems that other groups have not had the same success, we include a detailed description of the recommended procedures that others may follow in appendix 1. A detailed cost breakdown is provided in appendix 2 and a description of the initial chemical and bacteriological measurements is in appendix 3.
Key words: arsenic, dugwells, sanitary, coliform,
Introduction
The arsenic problem in Bangladesh has been widely discussed . About 20-40 years ago people in Bangladesh the past 40 to 50 years, have been abstracting ground water by sinking tube wells . The wells were cheap. The water seemed to be free of the bacteria that had caused cholera. This seemed to be a magic solution to the nation’s drinking water problems. But it produced its own very serious problems. About 30% of the wells contained too much arsenic. Physicians at Dhaka Community Hospital (DCH) became aware of the ailments caused by arsenic as early as 1982. But world attention was not brought to bear until the first (of eight) International Conference on arsenic held by Dhaka Community Hospital in January 1998 held jointly (in Dhaka) with Jadavpur University, Kolkata[1]. At that time also, DCH and Uposhon carried out a 500 village rapid assessment[2]. DCH and Jadavpur University carried out detailed surveys in many villages[3] . At that time there were several “obvious” conclusions.
(1) A short term solution might be acceptable if it was implemented on a wide scale at once.
(2) A long term solution should fit into a national water policy
(3) There was no reason for delay; short term solutions should be implemented at once.
(4) A simple return to unsanitary surface waters is undesirable
The proposals that were made at once were:
(i) to have a national survey of wells,
(ii) encourage well switching (use of a well without arsenic) and
(iii) install temporary (household scale) arsenic removal devices.
(iv) Use deep wells (deep enough to penetrate a clay layer)
However 7 years later, there was delay, the short term quickly became a long term and there are many villages still without pure water. Well switching has been variable: some estimates are that only 30% of villagers switched wells. Columbia University scientists find that the number is 60% in the area they studied, perhaps because they had an intense village education program. Moreover it is strongly suspected that continued pumping from a safe (green) well can bring arsenic laden water into that part of the acquifer. The arsenic removal devices proved too hard for many villagers to use and many of them were unsatisfactory and were abandoned[4]. And some scientists have cautioned against indiscriminate use of deep wells. Although the arsenic contamination of this deep layer is at present much smaller than the arsenic contamination of the ordinary tube wells at a depth of 40 meters it is unclear whether it will always remain so.[5] In Dhaka continuous extraction of ground water is non rechargeable at the same rate of extraction, and has resulted in severe lowering of the ground water level. According to the WASA report 2003 [6], the ground water level that was 11m in 1970s went down to 20m in 1980s.
In 2003 the Government of Bangladesh (GOB) promulgated a “National Water Policy”[7] which gives priority to surface water use among other options. These surface water options seem to be:
1) Encouraging a return to surface (dug) wells (DW), but with a strict adherence to WHO
sanitary standards.
2) Use of sand filters to filter pond water (PSF) or river water (RSF)
3) Storage of rain water
In all solutions, involvement of the local community seems essential. DCH is particularly suited to such pilot projects because each of their 40 local clinics can act as a focus for action. DCH chose the second of these surface water solutions, the use of dug wells, for this first demonstration facility in the Pabna district. This report describes three phases of the work starting in the year 2000, till 2003, and some indication of further developments in another district since 2003. Further tests on some of the wells in 2004/5 are also included. Other groups are actively studying other solutions, including use of deep wells, and we make no premature claim on whether, or where, a particular solution will prove to be the best.
The DCH Dug well Demonstration (Pilot) Project
Dugwells have been used for time immemorial, but were replaced by tube wells because of simplicity and in particular freedom from bacterial contamination without the apparent necessity of careful maintenance. A return to dugwells seems, therefore, an obvious possibility. However this has not been uniformly successful. This project was begun to demonstrate that it is possible to have bacteria free wells if due care is taken and in particular if WHO requirements were followed.[8] While this is obvious in a temperate climate such as UK, it is far from obvious in the tropical village conditions of Bangladesh. There were therefore several aims. Will the wells be bacteria free? Will the wells be free of arsenic and other undesirable chemicals? What will be the cost? What maintenance is necessary? Are there other conditions such as limited choice of sites that are necessary to achieve these aims? Will the wells be acceptable to the people? After the start of the project DCH noted that the Bangladesh government electrification program had already brought electricity to 50% of all villages and has the aim of bring electricity to them all by 2020. This makes it easy to install an electric pump to raise the water to a storage tank, from which it is gravity fed by pipeline to a number (6 or more) individual houses. This has proved very popular and is a major step toward the widespread acceptability of this solution. It is interesting that Ahmad et al.[9] found by survey that the availability of running water is more important in public perception than the fact that the water is arsenic free. The Bangladesh Arsenic Mitigation Water Supply Project (BAMWSP) has also stated its intention of providing 30 pipeline systems[10]. However we have no further information about them.
Although the project was begun in late 1999, it started in full measure in April 2002. In the first phase 39 wells were dug, (or in some cases reconditioned) by February 2003. These wells supplied 631 families and serve 3,250 users. Only one had a pipleine system attached. In phase 2 seventeen new wells were dug and all had the pipeline system installed. Another 518 families were supplied and 2,903 users were served. In phase 3, nine old wells were renovated (brought up to WHO sanitary standards) and one new one dug; all with electric pump, storage tank and pipeline. This supplied another 400 families with 2,400 users.
In all 66 sanitary dug wells were installed in this demonstration pilot project in the Pabna region. This region was chosen for a number of reasons. Firstly, the need seemed great in this area. In several villages all, or nearly all, tubewells showed excessive levels of arsenic. In several villages patients with evident arsenic related lesions had been found. Secondly, DCH has a clinic in Pabna where patients may be seen and water samples analyzed. Thirdly epidemiological studies of arsenic lesions are being studied in this region by DCH together with a group from Harvard University. The general geographical location of these wells is shown in figure 1.
Procedure for the installation of a Dug Well with Pipeline
March and April, which are the driest months in the country, are the best times for digging a well. During this period, ground water remains at the lowest level so that if the well hits water at that time it will always hit water. We believe that it is crucial to emphasize that DCH does not own the wells. The community owns the wells and is responsible for their installation and maintenance. DCH merely facilitates these, and in this paper reports upon them. Because of the crucial importance of the full participation by the community, and the fact that this has not always been achieved, we outline the procedures DCH have adopted to ensure this responsibility. DCH found that there were several major distinct activities, none of which can be omitted if success is to be assured: Community mobilization, Committee formation, Training of community workers and the caretaker, Site selection, Drawing of water supply network, Installation of dug well and pipe network, Community meeting, Water quality monitoring. These are detailed below.
Community mobilization
Various mobilization and motivational activities were conducted, such as courtyard meetings, to increase public awareness. Several meetings with the community were held in each village. Local Government of Bangladesh (GoB) elected persons and influential local people were present in meetings along with the DCH personnel. Community people including women, the poor and arsenic patients shared their situation, needs, opinions and preferences about mitigation options with DCH and others.
Committee formation
In each village a committee was formed for the supervision of each stage in the implementation. Each committee was responsible to maintain the option provided to them. DCH and the committees worked together to plan option installation and maintenance. The committee accepted responsibility to collect the community contribution. The committee decided the charges for water use for each family. A caretaker collected money from water users (usually 20 Tk or 35 cents a month for each family). Each family was provided with a water card for payment.
Training
Local mistris were selected for construction and maintenance of the options. They were trained on construction work options by DCH trainers. DCH trainers also trained caretakers and users of options.
Site selection
Sites for wells were selected in areas highly contaminated by arsenic. This was done after consultation with the community. Preference was given to sitting the wells near the patient families and the poor. All 66 sites satisfied guidelines provided for site selection, including but not limited to:
- Preparing a Dug Well 30-40 ft away from the latrine and dumping ground of waste materials
- Animals are penned away from the Dug Well
- The Dug well is installed at a safe distance from cropland and industrial area etc.
A detailed check list for adequacy of the site selection is being prepared taking account of the expereince gaines so far
Installation
A hole is dug with a diameter of about 36 inches. The depth of the well varies from place to place. A ring of cement or baked clay is set from bottom to top and the rings are joined (sealed) by cement to keep the well water safe from contamination from contaminated surface water. An apron of about four feet is made around the head wall and a 30-40 feet drain is constructed at the ground level to avoid water seeping into the well around the head wall. An electric pump pumps water from dug well to an overhead reservoir of 3,000 liters. This overhead tank is installed on an iron stand, 15 feet tall. The stand is fixed on the ground with RCC work. A main water supply pipe (made of 3 /4'' plastic) is connected with the tank for distribution of water to the household level. A GI pipeline of ½ inch plastic is connected with the main line to supply water to each individual household. 40-50 households are connected with a single main supply line. To prevent accidents, during construction of Dug Well, due to collapsing of side-soil and occasionally asphyxiation from carbon dioxide and methane gases- rope, ladder, a Bosun’s chair and other safety equipment are kept at the site. A 30-40 feet drain is constructed at the ground level to avoid water seeping into the well around the head wall.
Water quality monitoring and the Importance of Measurements
One of the most important functions of the village committee is the continuous monitoring and guarantee of water quality according to quality guidelines prepared by DCH in consultation with experts and according to the WHO guide lines. In this the village committee can call upon the advice and help of Dhaka Community Hospital and others. This aspect of the implementation is so important, and so often neglected that we emphasize it in a separate section here.
Failure to make adequate measurements has been at the heart of the tragedy of Bangladesh. For 20 years no one measuremed the arsenic levels in even a small sample of the millions of tube wells until it was too late. More recently many small-scale arsenic removal devices were installed without adequate measurements to demonstrate their efficacy. Some NGOs returned to surface waters without following WHO sanitary guidelines and without measurement of possible bacteriological contamination. For this, and other, reasons DCH have insisted on measurements from the outset. Because of the past failures in this regard, DCH recommend that a copy of all measurements be publicly available, for it is important that not only the individual who has the well be convinced, but also DCH as a whole and through DCH the wider community. The measurements of this pilot project are available in appendix 3 and more detail is available on the web at http://DCHtests.arsenic.ws.