Condominial sanitation could achieve MDG
The Millennium Development Goal (MDG) for sanitation means bringing an extra 1.9 billion people on-stream by 2015, globally. Duncan Mara, Professor of Civil Engineering at the University of Leeds in the UK, argues that this can only be achieved by abandoning conventional approaches to sewerage and adopting a condominial approach to provision, across social classes.There will be a lot of talk about the MDGs at the 4th World Water Forum (WWF4) in Mexico City in March and about the water and sanitation targets in particular. Much of it will miss the point.
In the 1980s, the years of the International Drinking Water Supply and Sanitation Decade, around 370,000 people received an improved water supply every day. To meet the MDG water target, 'only' around 310,000 will need to receive an improved water supply every day during 2001-2015. So we can do it, if we want to - and we all say we want to.
However, with sanitation, it's a different story. To meet the MDG sanitation target, about 440,000 people will need improved sanitation every day during 2001-2015, but in the 1980s and the 1990s we only managed to serve just over 200,000 per day. Therefore, global efforts need to be more than doubled.
How can this be done? We all know the sanitation technologies that are suitable for rural areas: VIP latrines, pour-flush toilets and, for those unable to afford either of these, some type of, at least partially improved, latrine, such as the SanPlat latrine.
As has been said many times, and over many years, rural sanitation is much more a sociological problem than an engineering one. However, I am not sure there are all the 'rural sanitation sociologists' we need if we are to meet the MDG target for rural sanitation - around 220,000 people per day.
It is a different story in urban areas where the same number, 220,000 people per day, need improved sanitation. We all say 'urban' areas, but we actually mean 'periurban' areas, that is, low-income areas with poor municipal services and slum areas with no such services.
The problem is that almost nobody at local level (i.e. local government engineers) knows what to do. All they know about is conventional sewerage, but this is wholly unaffordable in periurban areas, as was pointed out by John Kalbermatten at the World Bank in the mid-1970s. There is the added problem that almost nobody going to the WWF4 knows what to do either!
So what can be done in periurban areas? Usually housing densities are too high for on-site sanitation technologies, so latrines of any sort and pour-flush toilets with on-site leach pits are out of the running. However, these high housing densities offer scope to realise economies of scale for both water supply and sanitation.
The answer to the question is, in a word, 'condominial' - water supply and sanitation provision should only be made to groups of households and not to individual households. This provision to groups of households should become the New Paradigm - we know that 'more of the same' will not meet the WatSan targets, so we need to change gear, and the New Paradigm is probably the only top gear we have.
In the 1980s roughly twice as many people in rural areas received improved water supplies as people in urban areas. To meet the MDG water target this has to be reversed: twice as many periurban households need to be served as rural households. Condominial water supplies will have to be applied on a very large scale. There are three basic variants:
- Standpipe cooperatives with one tap per group of households.
- Yard-tap cooperatives with one tap per member household.
- Multiple-tap, in-house cooperatives, that is, cooperatives of non-poor households (of course non-poor households need not form cooperatives, but those that choose not to should pay more for their water and sewerage).
The advantage of condominial water supplies is their very much lower costs, for example, in Parauapebas, a mining town of about 200,000 people in northern Brazil, the cost was US$44 per connection for multiple-tap in-house cooperatives with a design supply of 250L/d per person. This compared with US$167 for conventional supplies. This cost reduction was mainly due to the fact that 287km of streets were served by only 43km of pipes.
Condominial sewerage, also known as simplified sewerage, has been around since the early 1980s, much longer than condominial water supplies. It is no more than conventional sewerage stripped down to its hydraulic basics and with improved layouts, often in the backyard of a housing block, and simple inspection points and junction boxes rather than expensive manholes.
The result is that a 100mm diameter sewer laid at a minimum gradient of 1 in 200 can serve around 1100 people, each with a water consumption of 100L per day. So successful has condominial sewerage been that it is used in rich areas (in fact very rich areas), as well as poor areas, in Brasilia. Costs in Parauapebas were half those for conventional sewerage.
It is a simple matter for a water supply cooperative to become a water and sanitation cooperative: member households take with advice from the local water supply and sanitation agency and simply choose which sanitation system they will all have. Often this will be condominial sewerage as housing densities are commonly too high for on-site systems such as VIP latrines, pour-flush toilets and ecological sanitation.
Condominial sewerage is perfectly compatible with standpipe and yardtap supplies, as well as, of course, with in-house supplies. Very poor households and the homeless (street children and 'pavement dwellers', for example) are best served by community-managed toilet blocks of the type developed by SPARC in India.
My view is that the MDG targets for water and sanitation can only be met if condominial water supplies and condominial sewerage are implemented on a truly massive scale, especially in Asia. Why 'especially in Asia'? Because most of the 200,000 people in the world who need to receive improved water supplies, and the 220,000 needing improved sanitation, every day during 2001-2015 live, or will live, in Asia.
However, we cannot neglect Africa, although I think the we can leave Latin America to the Latin Americans as this region is the best served at present and has the lowest number of people needing improved water supplies and sanitation; it also has good and innovative engineers.
Outside of Latin America, there is huge ignorance of these 'condominial' technologies - the technologies at the heart of the New Paradigm. Therefore, we need dissemination and training on a correspondingly huge scale, particularly at local level.
Further, national design codes need to be changed to incorporate these technologies. They are being implemented, but only at small scale. It really is time to change gear as time is running out fast.