September 09, 2006

THE government intends to construct 6,559 water treatment plants all over the country to provide safe drinking water to people. The project will cost Rs7.5 billion and will be completed by December 2007. A total of 554 plants have already been installed in various parts of the country in phase one and 6005 plants will be installed in phase two. According to reports, about 30 million people will benefi from the project. On a volumetric basis, three types of plants will be installed: 2,000, 1,000 and 500 gallons per hour capacity plants. The project is a component of “Khushal Pakistan Programme”.

It is reported that nearly 50 per cent of the plants installed are not working properly. Some plants are providing contaminated water, which is spreading water-related diseases. There have been reports of outbreaks of gastroenteritis.

The government is undertaking the Clean Drinking-Water Initiative to improve the quality of life and meet Millennium Development Goals (MGDs). While the MDGs are to be achieved by 2015, the government intends to complete the programme by 2007, eight years ahead of the deadline. It should be noted that, the UN Millennium Goals do not talk about “safe drinking-water” alone. It adds “sanitation” to it. Environmental engineers feel that the concerned UN Millennium Goal is inadequate. It does not include “hygiene promotion.” A complete and comprehensive approach towards improved public health should be water supply-sanitation-hygiene promotion, if one wants to achieve the objectives of a healthy environment. Even if a water treatment plant, under the present initiative, produces acceptable effluent, the water will still be contaminated if a proper water distribution system is not provided.

According to the World Health Organisation (Who), proper water storage is probably the most important way of keeping household water clean. The water can get contaminated during the process of treating water resources. Storage containers, therefore, need to be well-designed and should protect water from contamination. Again, if sanitation facilities are not proper, dirty water will be a result of that.

Hygiene behaviour

According to the UK Deparment for International Development (DFID) (1998), in the developing world, inadequate water supply and sanitation facilities are the prime causes of widespread and serious health problems but improvements in these services show few health benefits unless they are coupled with improved hygiene behaviour.

The architects of the present Clean Drinking-Water Initiative should know that, in addition to the linkages of water supply with sanitation and hygiene, they need to learn about environmental health in sufficient details if a holistic approach to communal health problems is aimed at. The bottom-line of the current project should not be installing a water plant at a public place and then running away from the project; there should be a quantified improvement in the health of the people.

Water-related diseases

Cairncross and Feachem (1993), classify water-related infections’ transmission into four groups and suggest preventive strategies:

1. Water-borne (typhoid, paratyphoid, hepatitis A, poliomyelitis, cholera, giardiasis, amoebic and bacillary dysenteries); preventive strategies are improved quality of drinking-water and prevention of casual use of unprotected sources.

2. Water-washed (skin and eye infections, louse-borne typhus and relapsing fever); preventive strategies include increased water quantity, improved accessibility and reliability of domestic water and improved hygiene.

3. Water-based (schistosomiasis, guinea worm, clonorchiasis, fasciolopsiasis); preventive strategies are reduce contact with infected water, the controlling of the snail population and reduced contamination of surface waters.

4. Water-related insect vector (malaria, filariasis, river blindness, yellow fever, dengue fever); preventive strategies are improve surface water management, destroying breeding sites of insects, reduced visits to breeding sites and mosquito netting.

According to the DFID, good water quality is important, as a fecally-contaminated water supply can lead to the direct ingestion of disease-causing organisms by many, possibly causing an epidemic. An adequate quantity of water, however, is more important in controlling non-epidemic diseases which, in fact, exert a higher toll. Increasing the quantity of water available allows better hygiene and can, thus, prevent disease transmission from the fecal contamination of hands, food, or household utensils. Washing hands and utensils in dirty water can still reduce contamination and, is better than not washing them at all (DFID, 1998).

Drivers of public health

1.8 million people die every year from diarrhoeal diseases (including children); 90 per cent are children under five, mostly in developing countries. 88 per cent of diarrhoeal diseases are attributed to an unsafe water supply, inadequate sanitation and hygiene. Improved water supply reduces diarrhoea morbidity by six to 25 per cent, if severe outcomes are included. Improved sanitation reduces diarrhoea morbidity by 32 per cent. Hygiene interventions, including hygiene education and promotion of hand washing, can lead to a reduction of diarrhoeal cases by up to 45 per cent. The improvement in drinking-water quality through household water treatment can lead to a reduction of diarrhoea episodes by 35 to 39 per cent (Who, 2004).

In Pakistan, only 48 per cent of the rural population has access to safe drinking-water, while only 23 per cent of the rural population has sanitation facilities. For the urban population, 55 per cent has access to safe drinking-water sources and, 35 per cent has adequate sanitation facilities.

A conventional approach

Quite often in developing countries, the conventional engineering approach is adopted for water treatment plant design. The approach involves planning on an individual town basis, in which a town is surveyed and water demands are ascertained. A preliminary engineering design is done, which is followed by a detailed engineering design. This approach allows a rational, specific and flexible design of the water treatment plant. Since, the plant is designed based on the town’s sanitary needs, the water quality and quantity usually meets the requirements. This is a preferred option in developing countries and has been practiced extensively for decades.

Another approach is the use of custom-designed water treatment plants, which are used typically for smaller installations in industrialised countries and in emergencies. The disadvantages of this approach are that they are rigid, typical and inflexible. They are not amenable to improvements and are prone to frequent breakdowns.

The two types of standardised designs used for small installations are package plant and modular plant designs. Package plant designs refer to a compact treatment system usually made of steel. The treatment units are manufactured wholly in a factory and are transported to the site. Modular plant designs also refer to compact treatment units but the difference is that they are generally made of concrete and are partly or entirely assembled at site. High-level skilled operators are required for the operation of such technologically advanced units. These types of plants are not suitable for small towns and villages, where usually, highly skilled operators are not available and there is a tendency of dereliction of duty on part of the staff. This is one of the major reasons why some of the installed plants under the clean water initiative are not working properly.

Package plants are suitable for small communities in industrialised countries, due to high construction and labour costs. They are not suitable for developing countries because it requires procurement of materials. There is also a lack of technical know-how. Then, use of steel plants with corrosive chemicals (chlorine, alum) requires special attention and knowledge.

Clean Drinking-Water Initiative

The Clean Drinking-Water Initiative will be executed through five packages. Package A talks about tube wells as source water. It says that the source water should not contain high concentrations of nitrates, nitrites, calcium, magnesium, and total dissolved solids (TDS). The water shall be treated through rapid sand (multimedia) filters, granular activated carbon (GAC) filter and ultraviolet sterilisers. Package B lists the source of water as overhead tanks with other conditions being the same as in package A. Package C lists the source of water as tube wells, with some other conditions as in package A. Package D says that the source of water contains high concentrations of nitrates, nitrites, calcium or magnesium. The treatment system should contain a nitrate chamber and water softener chamber. Package E is for source waters containing high levels of arsenic, TDS and other organic pollutants. It further says that additional appropriate treatment technology will be provided.

It is not known what pre-filtration is intended to mean, in this context. Typically, pre-filtration, in the shape of “roughing filters” is provided for treating highly turbid surface waters (more than 50JTU) when conventional slow sand filters are used as a rural water system.

The pollutants of primary concern for public health are fecal coliforms (E.coli), viruses, protozoa, helminth, cyanobacteria, turbidity, colour, fluoride, lead and iron. In addition, the dissolved oxygen parameter is important for aesthetic reasons. A critical review of the five packages shows that, either they have been prepared by people not qualified in the field of environmental engineering or by some outside “fly-by-night” consultant.

Surface water sources are available throughout the country. They should have been given preference. That would have made the water treatment system relatively cheaper and reliable. This could have avoided costly, problematic and maintenance-intensive GAC and UV filters.

The logic behind water treatment

When tube wells are the source of water, then, typically, filtration units are not required. Most of the tube wells are relatively free from pesticides, which would preclude the use of GAC – appropriate for waters containing high levels of pesticides and other organic chemicals. UV filters are not suitable for communal water systems. Either a conventional method of disinfection should be used, or a post slow sand filtration system, designed to remove organic contaminants, should be used. This will have an additional useful advantage of removal of fecal coliforms.

Overhead tank water, as a source of water is a strange water source. Only water of acceptable quality is pumped to high service reservoirs. There is no need for any treatment for the overhead tank’s water. Stagnant overhead tank water may become low in dissolved oxygen, which can be treated, if required, through sprinkling or splashing.

Water from deep wells does not require rapid sand filtration, GAC and UV treatment units. The only concern in deep wells is the presence of iron. It is preferable to discard the source with high iron content. Iron levels of more than four mg/l (milligrams per litre) are not acceptable as it imparts taste and stains cloth. UNICEF conducted an extensive study in Sindh in 2002, regarding presence of arsenic in wells and designed a household filter system for its removal. If other sources of water are available, then well water containing high levels of arsenic should be discarded.

In packages D and E, water sources with high inorganic constituents (nitrates, arsenic, calcium) have been listed, with treatment units of rapid filters, GAC, UV system and other appropriate units. Since communal water system is the focus of the project, it is not advisable to go for advanced or tertiary treatment units. They incur heavy recurring costs and would not be a sustainable water system.

Package D mentions the provision of a nitrogen and water softener chamber. Nitrate is removed by the ion exchange method. Ion exchange of chloride for nitrate is the simplest method for removing nitrate from water. The sulfate content in water influences the nitrate removal efficiencies. The more the content of sulfate in water, the less the removal efficiencies for nitrate. The system is complicated to operate upon and is not suitable for small-scale communities. One major problem is the disposal of nitrate-laden brine, which cannot be easily disposed of, due to eutrophication potential. The best course is to discard the source of water containing high levels of nitrates.

The way forward

In order to rationalise the institutional set-up, the project offices should be set up in all provinces, instead of having one in Islamabad. The provincial offices should be headed by persons qualified in the field of environmental engineering with field of specialisation as water and wastewater engineering. It should be equipped with qualified support staff. The provincial office should adopt a participatory approach for water supply, sanitation and hygiene interventions. The days of solving water and sanitation problems with concrete and pipes are over. A participatory approach allows community’s involvement, empowers people for responsibility, respect tradition and culture, includes gender considerations, mobilise public-private partnerships and creates willingness-to-pay criterion. A demand-responsive approach to the water and sanitation interventions will determine what levels of service the users are willing to adopt.

Suitable projects should then be formulated. They should preferably be conventional water treatment plants with slow sand filtration systems. The Presence of a particular pollutant in water should be dealt with for that particular plant with an option of discarding that source for a more favourable source. The locations of plants should be fixed in consultation with district and taluka administrations.

The water treatment plants must be coupled with the water distribution system. The level of service should be decided with local administration. For example, in case of water supply, the level of service can range from high (piped connections in houses) to minimum (communal hand pumps). In case of sanitation, the level of service can range from high (sewerage system, or flushed toilet with septic tank and soakpits) to minimum (simple pit latrines on householder’s plot). Hygiene education would be an important adjunct of the programme. An extensive programme of hygiene promotion needs to be laid out. The whole system should be made sustainable by making the community to pay for the facilities.

With Rs7.5 billion in hand and 6,005 plants to be installed, it is a “tall order” and constitutes a mega programme, having tremendous potential for the health of the people, provided it is managed by technically qualified and honest people. It is a one-time, great opportunity for the country to improve the environmental conditions and public health of the people, provided a sensible and technically sound framework is laid down.

The writer is a freelance contributor

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