Well, Karachi is famous for inventing simplified sewerage at the same time as condominial was being developed in Brazil, so I think you won't need to go far from home to see it in action. Check out the orangi pilot project. www.opp.org.pk

But as far as I know, it has not been installed on an industrial scale, like it has in Brazil. Maybe you can help us understand why.

Almost as a sort of companion publication is the report by the United Nations Centre for Human Settlements (Habitat), Nairobi 1986, with the caption of The Design of Shallow Sewer Systems. The publication is attached.

According to the publication:

Shallow sewers are designed to accept all household wastewaters - excreta, toilet flushwater, and sullage — in their fresh state for off—site treatment and disposal. They consist of a network of small— diameter pipes laid at flat gradients in locations away from heavy imposed loads, such as vehicular loads, usually in the backyards and narrow back alleys of both planned and unplanned settlements. This allows short overall lengths of pipework to bé laid in shallow trenches (hence the name) with the small inspection chambers provided along their lengths to facilitate access for maintenance. Most high density low-income housing areas have few motor—accessible roads within them and, hence, a majority of the sewers may be laid at shallow depths throughout most of their length. Shallow sewers are designed to be flushed frequently: essentially, all households within a block are connected to the sewer that passes through it. This is required not only to ensure trouble-free operation but, more important, to interrupt intra-community contamination.

Shallow sewers do not rely on large quantities of flush-water for trouble-free operation; instead, they rely on the high frequency with which wastewaters pass through the system. Densely populated areas offer ample opportunities for such operation. At the head of the sewer network, wastewater solids are flushed along by successive waves of wastewater, and, if any solids settle out in the sewer invert, wastewater builds up behind the deposit until the pressure is great enough to set it moving again. Such back pressures are easily established when the diameter of the pipe is small, since leakages
past the deposited solids are minimized and an effective back pressure can be built up. Solids progress along the top end of the sewer line in a sequence of deposition — transport — deposition — transport, and this continues until the sewer has drained a sufficiently large area for the flow to cease being intermittent. Shallow sewers are also laid out in such a manner that they are located adjacent to the wastewater generating points within
households. Hence, peak discharges created during flushing assist solid transport even when water consumption and, hence, wastewater generation are limited.

For design engineers, this is a useful and engrossing report.

F H Mughal
PS: This system cannot attach the publication. It can be assessed at: www.ircwash.org/sites/default/files/332-3964-2.pdf

Talking of David Duncan Mara, attached is a publication of simplified sewerage.

According to the publication, the key features of the system are as follows:

In order to reduce costs, simplified sewerage is developed as an in-block system, rather than – as with conventional sewerage
– an in-road system. The key feature of an in-block system is that sewers are routed in private land, through either back or front yards. This in-block or back-yard system of simplified sewerage is often termed condominial sewerage in recognition of the fact that tertiary sewers are located in private or semi-private space within the boundaries of the `condominium’.

Simplified sewers are laid at shallow depths, often with covers of 400 mm or less. The minimum allowable sewer diameter is 100 mm, rather than the 150 mm or more that is normally required for conventional sewerage. The relatively shallow depth allows small access
chambers to be used rather than large expensive manholes.

This is pretty useful and inspiring publication.

F H Mughal

Dear Ms. Grace,

Thank you for your kind help. I'll contact Mr. Neder for more information. This is an interesting topic.

Regards,

F H Mughal

Also, I am working with two Brazilian engineers who have developed a 5 day hands on course on how to do condominial. They can teach it in Spanish and Portuguese, but we are hoping to create an English language version. As well, there is a free software for condominial design which will be available in English, Spanish and Portuguese. It will be ready soon, probably in the next month. We will put the link up here when it is ready.

Klaus Neder is the only one in either company who speaks English, as far as I know. He is at CAESB in Brasilia. This email address is being protected from spambots. You need JavaScript enabled to view it.

Here is a short video thatKlaus made recently.


I'm not sure if a recent report exists. The InterAmerican development bank is working on an operations and maintenance report now in Brasilia, but that study has not been done yet. But, Klaus probably has some useful information for you.

All the best,
Grace

Dear Ms. Grace,

Thank you for your help. I'll myself the companies. Kindly send me their contact information.

Regards,
F H Mughal

Hi FH,

Maybe what might help you is an operations & maintenance report from the water and sanitation companies themselves? Something like that may not be available publicly but I can ask them if they can share it with you if that is what you have in mind.

Yes, my understanding is that Mara has retired. Earthea Nance has done some of the only evaluations in English, but they too are from more than a decade ago. I'll ask her to get on and post what she thinks are the most relevant papers. There is work being done in Portuguese, but interest died out in English for a while. My opinion on why they are not spreading is that they are spreading - but slowly. They are spreading where the people who know how to do them can travel in Latin America and other places where the language is not too big of a barrier. Most of the practitioners in Brazil don't speak English, and it takes more than knowing how to physically put them in to get a system going. Aside from the knowledge gap there are often legal barriers, prejudice against a simplified system and a big learning curve on how to make the participation work. Another problem is that the technology is not being taught at any university - it is basically ignored within Brasil. That is part of the idea of the institute - pass this knowledge on in and outside Brazil before all of the practitioners retire and it is lost.

I had a look at what we have on condominium sewers in the SuSanA library by putting "condomi" in the search field.
It gave 13 results: www.susana.org/en/knowledge-hub/resource...ndomi?search=condomi

This publication by Melo might be the closest to what Mughal is looking for, but it's from 2005 (13 years ago - has a lot changed since then?):
www.susana.org/en/knowledge-hub/resource.../library/details/441
Melo, J.C. (2005) The Experience of Condominial Water and Sewerage Systems in Brazil -Case Studies from Brasilia, Salvador and Parauapebas

One wonders why condominial sewers have not spread further, given that they have been around for such a long time. Duncan Mara has also published a lot about them. Actually a good state of affairs is summarised in this forum thread, see in particular the post by Rémi Kaupp:
forum.susana.org/conventional-sewers-sim...-simplified-sewerage
The title of that thread is "Any recent reports in English assessing the latest in condominial/simplified sewerage?".

Grace, perhaps you also would like to comment in the other thread, It would be very useful to hear about your opinion!

Regards,
Elisabeth

Dear Ms. Grace,

That June 2000 document is an interesting report. However, I'm more interested in the Brazil's monitoring and evaluation report, as you have pointed out.

Kindly share the documents, when they are ready in English.

Regards,
F H Mughal

Hi FH,

Are you looking for a technical manual? That exists on the web.

www.google.com/url?sa=t&source=web&rct=j...eyNZCaBpvt1IBcQZBh7e

If you are looking for a technical evaluation, some exist in Portuguese. I'm working on getting a virtual condominial sewerage institute up, and will be translating things into English as soon as I get funding for it. If you have a specific idea of what you are looking for I can see if it exists in Portuguese and put it up, and then you can use Google translate.