A socially, ecologically and commercially sustainable solution to the Arsenic problem in Bangladesh
Background
According to the United Nation’s World Health Organisation (WHO), the arsenic contamination of water wells in Bangladesh has caused the worst mass poisoning in history. After having studied the problem for almost a decade, the World Bank has published a remarkably candid report in April 2005. The title Towards a more effective operational response to the Arsenic problem indicates that what has been achieved this far in the international efforts to remediate the catastrophe has not been entirely successful.
Although the report concentrates on Bangladesh and South Asia, arsenic contamination of water is being discovered all over the world at an alarming rate. Arsenic poisoning affects millions of people in such diverse countries as Mexico, Argentina, Chile, Hungary, China, India, Cambodia, Vietnam, Thailand, Nepal and Ghana. Also more than 4,000 US water utilities serving 13 million people don't meet the US Environmental Protection Agency’s (EPA) standards for arsenic. Add to this all private wells that are as yet unregulated as far as arsenic is concerned.
In many additional countries the problem may surface as increasing strain on water resources mandate the use of formerly untapped groundwater sources. Arsenic is, after all, the twentieth most common substance in the earth crust and it has also been, and is, used extensively in industrial undertakings.
The World Bank finds, like WHO and the EPA have found earlier, that there is no existing technology that is suitable for removing arsenic on a household or village level. The conclusion of the report is that the only viable solution would be the introduction of large scale municipal water plants.
However, in a hot climate, the balance between microbiological contaminants and disinfectants is impossible to maintain in even the most up to date treatment plant. This means that you either risk to get sick to your stomach or to become affected by disinfectants and disinfection by-products. Drinking water from a municipal water plant will therefore never be a first choice for the affluent.
The present trend in all hot climates, Italy, Spain, Southern and South-Western United States, Middle East, Malaysia, Indonesia, is that the sales of bottled water and private water purification equipment skyrockets. Affluent city dweller would not use municipal water for drinking in Bangladesh either. So the huge investments needed for building and running modern water plants would in the long run be a non-solution to the arsenic problem.
In Bangladesh there is an added difficulty in that the surface water which is traditionally used for drinking is extremely difficult to purify because it is affected by recurrent flooding which blends latrine, agricultural chemicals and industrial waste into the feed water of any proposed water plants.
For small communities that cannot sustain large water plants, the situation is even more difficult. EPA has recently commissioned twelve demonstration plants for removing arsenic in small communities in the United States. All of the proposals seem expensive and not entirely reliable and none of them has solved the problematic disposal of arsenic residue. It does not seem to be an easy road to travel in the US and would certainly be even more difficult in Bangladesh.
Removing arsenic from the water with ion-exchange resins, absorbing or adsorbing substances such as iron or aluminium compounds, as has been suggested this far, will produce dangerous arsenic residues. These methods will also leave most other risk contaminants in the water and have often been shown to increase the risk for bacterial recontamination of the water. Any intervention must be judged not only by how well it reduces arsenic but also against the criterion of minimizing risks of water-related infections.
One obvious solution that has been proposed in Bangladesh is to close arsenic containing wells – a very large part of the 10 million wells – because “in many villages unsafe wells are near a safe well”. This would entail many extra miles of walking for the women in Bangladesh and the added strain on the remaining wells would probably hasten the release of arsenic also into these wells. Although there are presently strata in the ground that do not release arsenic, no doubt the ground contains arsenic all over the country and water has a way of moving around under ground and also a way of picking up and, at least partially, dissolving everything in its path.
Avoiding contaminated wells may therefore prove to be a passable temporary solution, but also dangerous, since it is difficult to monitor arsenic content in the wells on a continuous basis.
Providing absolutely pure drinking water from the tap has been the ambition of international water professionals for more than a century. Time has proven that in most places, it does not work. Although water professionals are reluctant to give up their dreams and still keep arguing that water from the tap is the best solution, consumers are already choosing another path. They buy bottled water or they buy special purifiers for purifying tap water before drinking. Also in Bangladesh, the realistic and sustainable solution is bottled water and home water purifiers – according to consumer’s choice.
This calls for community scale treatment methods for bottled water and household scale treatment methods for home water purification. These methods must remove arsenic and microbiological contamination as well as other pollutants from the water without adding new health hazards and without causing environmental contamination.
It goes without saying that to be accepted by the consumer, these methods must have low life cycle costs, be technically robust, reliable, easy to maintain, socially acceptable and affordable.
Such methods are not available off the shelf today as the World Bank report shows. To pioneer a method and business in this field that is socially, ecologically and commercially sustainable will therefore have relevance also for other communities around the world that sooner or later come to grapple with this extremely difficult to remove substance, Arsenic. In the following we will present one possible approach.
Distributed utilities
What is proposed is to integrate the arsenic remediation into the wider context of general business structure and welfare development. The proposed bio-gas cogen equipment will use human and agricultural waste for fuel to produce electricity, pure water and hot water as needed.
Improved health and work capacity from better water will increase individual productivity at the same time as locally produced electricity for electric motors, communications and IT will increase general productivity.
The equipment is state-of-the art equipment that is especially tuned to be maintenance free. It will consist of small power plants that run on bio-gas from bio waste and a water purification unit that runs on the waste heat from the engine. So, agriculture will not only provide food, but also electricity and pure water – and do this in a sustainable way.
In certain areas of the world, and especially in Bangladesh, there might be a short term economic advantage in using natural gas instead of biogas – essentially in order to speed up the introduction phase.
Distribution of the drinking water will be done in containers of convenient sizes, 1,5 or 4 liters. A modern bottling plant will therefore accompany the equipment.
As an example, a compound may deliver 1 MW of electricity and 100 M3 water per day. Additional water output can, if necessary, be obtained by adding solar panels to the system.
Ecological sustainability
Distributed energy and water production will eliminate the need of huge dams and other environmental disruptions. And it will avoid huge investments in transmission infrastructures and the cost of their up-keep.
Neither the water treatment nor the energy production will create waste and modern engines create minimal air-pollution. And they will not contribute to global warming. Rather, both processes utilise waste and return whatever residue to nature’s cycle, even minerals to the soil which will stop the present depletion of agricultural lands.
After the investment is made, the running costs are minimal. The total running input for the system, except maintenance, will be human and agricultural waste. According to a study made by the Swedish Aid Agency Sida, the world-wide energy content of agricultural waste approximately equals the energy content of annually used petrochemical fuels.
Social sustainability
A distributed utility will of course reduce poisoning from arsenic and other contaminants in water. Beyond this it will contribute to the development of the society by providing two of the most important factors for development, electricity and clean water. In addition it will free the human work now being used for fetching and treating water. By increasing economic equality, it will also empower local people and thus reduce profiteering and bribes.
Commercial sustainability
Probably the most important aspect of this solution is that it will empower all the people that are beneficiaries of the systems and support their move from dependency to economic self sufficiency. Specifically it will, of course, benefit the people who are directly involved in the commercial implementation and operation of the equipment.
Small is beautiful
Distributed utilities could vary very much in size, from a few hundred kW of electricity production and a few thousand liters of clean water per day to several MW of electricity and hundreds, maybe thousands, of cubic meters of water per day. What they all have in common is that the electricity is delivered through a local grid and the drinking water is delivered in bottles and containers – locally or regionally.
Costs
Assuming a rather large plant with an electrical capacity of 1 MW, 24 000 kWh electricity and approximately 100 000 liters of water is produced per day.
The capital cost for such a plant will be approximately 2 million US $ and it should be written off in five years although the real life will be much longer, more than ten for the power and water equipment, perhaps less for the bottling equipment.
Another capital cost would appear if there is no local grid to connect to. Then one would have to build a local grid. Also, assuming that the water is not bought by a retailer, there would have to be delivery trucks for distribution to retailers or directly to end users. These costs fall outside of this calculation and would have to be added to the final prices of the products.
The bio waste for the engine will initially have a collections cost and later when the use of bio-fuels is more common it will have a market price. A probable future market price should be used in the feasibility.
The power equipment and the water treatment need very little maintenance and service whereas the bottling equipment needs more. We can assume an average of a few percent of capital cost annually. Since the equipment is largely self-regulating, the labour cost is not high. There are virtually no consumables for the water treatment equipment. For the power plant, apart from bio-fuel, there is lube oil and hardly anything else. For the bottling, the cost of bottles can be calculated on non-returnable bottles although in most cases, because of the local character, bottles would be reused.
Total cost including depreciation, interest and operation would be less than 1 million US$ per year. A system ten times smaller in size (2 400 kWh electricity and 10 000 liters of water per day) would have an annual total cost of approximately US$ 200 000.
Income
Electricity: In most of the target areas there is no electricity or not sufficient electricity. Many of the people may not be able to afford electricity. However, in the long run everybody should have electricity. Everybody would benefit from electricity and will eventually be able to pay for electricity.
To calculate the potential sales of electricity is the most important part of the feasibility plan for each project and will determine what capacity of equipment is included. If there is a small market for electricity at the actual spot, the basic system may produce less water than desired, but water production can be augmented by solar power or heating from biomass.
Water: The water produced will be completely free from arsenic but it will also be free from any other known or unknown contaminations. This will be a strong marketing point in an area that is afflicted by arsenic, but also in any other market.
Small plants will sell their water locally to villagers in the neighbourhood. In very destitute areas we would expect that the water is initially purchased for the villages by NGOs such as BRAC and possibly by international Aid agencies. However, no project should be financed unless it has a clear long term commercial viability.
The larger plants should have a wider perspective. They can market – “the cleanest water in the world” – to adjacent towns. A very imaginative entrepreneur could also start an export activity. We would support with water expertise and marketing know-how.
Site specific feasibility
With an output of 8.640 MWh electricity and 36 million liters of bottled water per year at an annual cost of 1 million US$ the entrepreneur should be able to develop a profitable business.
Although there would be standard models for the operations, each unit would have to be evaluated in its own context. A bankable feasibility study will have to be prepared by the aspiring entrepreneur. We will of course assist with figures and calculations but in the end, the viability of the project will have to be the responsibility of the person or team that runs it.