The Orangi Pilot Project (OPP) in Karachi, Pakistan is a very well known low-cost sewerage project, but what is not so well known perhaps is that the site gradients in Orangi were greater than the minimum required sewer gradient, so hydraulically at least the project was bound to succeed. However, when this low-cost sanitation technology was applied in other cities in Pakistan, problems occurred as the site gradients were lower than the minimum sewer gradients.
I remember, after I gave a talk on simplified sewerage some years ago at a WaterAid meeting in London, a young woman engineer from OPP came up to me and asked if I’d go to Karachi and teach OPP staff how to design sewers! Well, nothing came of that, other than a realisation on my part that sewer hydraulics are incredibly important – a fact that really needs to be more widely appreciated.
About Me
- Duncan Mara
- University of Leeds, United Kingdom
- I'm an emeritus professor of civil engineering at the University of Leeds in England. I've been working on low-cost sanitation in developing countries since the mid-1970s, and also on low-cost wastewater treatment and reuse. I was a lecturer at the University of Nairobi, Kenya, 1970-73 and then a senior lecturer at the University of Dundee, Scotland, 1974-79 before moving to Leeds in late 1979. I was a visiting professor of sanitary engineering at the Universidade Federal da Paraiba in Campina Grande, northeast Brazil, during 1976-95, and since 1996 I have been a visiting professor of environmental engineering at the Instituto Cinara, Universidad del Valle in Cali, Colombia.