Dear Dean,

I fully understand ALL of your disappointments.

In my educated guessing this “simple sewer” example is just one of many “reinventions of the wheel” in the sanitation sector (see e.g. CW’s) and other sectors too and is in many cases only called “innovative” just to obtain R&D or project funding from uninformed people who deciding about money.

In this forum the number of practical thinking people who are sharing Open Source - Creative Commons simple and practical ideas like you, Bogdan, Krishan and so one becoming over the years very rare, in my personal opinion because the SUSANA is more and more on the money drip of private organisations like Bill Gates’s with all “necessary” implications. In my opinion, a Sanitation Community does not exist, just many competing isolated individuals and organisations that look just for their own selfish forthcomings by creating temp and permanent changing money drove alliances.

100% sustainability is just a “tool-word” but in reality, it is only about stagnation. See explanation and graphic by Marc LEIBER at min 3:17:
What is our goal/future: Cooperation - Sustainability - Competition?


Again, even all this distractive developments are very understandable and I can not condemn this all with my personal moral-hammer


Take care

Detlef

Hi Detlef,

I am not questioning the relative success of the simplified sewer as a technology, but that this project was touted as innovative and sustainable. Looks to me more like trying to reinvent the wheel.

Yet another opportunity lost to the sanitation community? One where the plunge was taken with very little thought to the art and available technologies? This forum could have been part of the discovery exercise before embarking on design, rather than 'do the job in isolation and ask questions later'.

I ask what was "sustainable" about this project and what was the innovation here that justified external funding? The claim on the VIA website was that this was a "pilot innovative project". So what is new or innovative?

Then, on sustainability "The project management adopts an integrated approach to increase the value and use of all waste resources". Is this for real? What actual sustainability criteria were considered? I am not convinced that this project as it stands fulfils any genuine sustainability objectives. I'm sure that simplified sewers have the potential to deliver just that, but not until innovation actually takes place that attempts to address the shortfalls that have limited uptake of the technology. How do the agencies that are trying to make a difference weigh innovation and sustainability in making their funding decisions?

The opportunity for this community is to facilitate innovation, in an attempt to overcome the issues that have stymied the technology for decades, in particular:

1. generation of sludge and the need for treatment of sludge; 
2. the need to desludge the interceptor tank regularly; 
3. overflowing of interceptor/septic tanks and the need for removal of resulting blockages;
4. greenhouse gas generation from anaerobic digestion (or more accurately not utilising the gas).

 

Vermidigesters, on the other hand, cannot overflow solids into the sewer, they produce humus that can be removed by the layperson, the decomposition is aerobic and rapid and cost is lower than for interceptors.

It's ideas and the sharing of those ideas that will take this community forward.

cheers
Dean

Dear Dean,

Kindly see sswm.info/node/8235
Prof. D. Mara of Leeds University is a key name in this regard.

short History of this "Open Source" technology:
Simple sewage systems without fecal solids flooding have been in use since the 1950s-60s. In the former Northern Rhodesia (today Zambia) this system was developed as a "simplified sewerage" by the British civil engineer Mr. LJ Vincent, later also "settled sewerage" "condominial sewerage systems", "low cost sewerage", "effluent drainage", " solids-free sewer "," septic tank effluent filter system "(STEF)," FLAT ", etc. called. About 30-40 years later, in Brazil and also in rural areas of the USA (STEP / STEF ) (www.cityofcamas.us/pwstepstef) and in Australia and in many emerging countries this simplified system been built.

a good pdf-document from Illinois, USA: www.iacaanet.org/docs/programs/alt_wastewater_il.pdf

Not surprising, Consulting Engineers and larger construction companies = "concrete farmers" do not like small and common sense sewage systems like this in larger scales around the world, as profit margins would be small too...

Good work by Gert.

Best Regards.
Detlef

Gert wrote: The WWT has an capacity of 6000 people IF they use 1 liter water per flush. People are happy with that, because of the water shortages and price.

While I think solid-free sewerage is an interesting technology in certain circumstances, it would seem that with such a low flow it is not necessary to remove the gray & black water from the plots? You might also run into significant smell problems from the sewers if the water basically dries up in the pipe due to low flow.

Hi Gert,
If you don't have a water lock you will need active ventilation in your ventpipe if the toilet is indoors. Active as in positive pressure at all times (e.g. fan), otherwise you will get odours from the anaerobic digestion in your interceptor/septic tank. A water lock is the simpler way to go and although that requires more flush water than e.g. sato pan, you could reuse handwash water for that.

cheers
Dean

I'm surprised that such a project would be undertaken (apparently) in the absence of being adequately informed. Can I assume that "innovative" in this context means by being "in the dark" about the options, just try out ideas and then ask questions later? There doesn't seem to be any information provided on the website, nor provided here.

I haven't picked up on the advantages of this specific type of system yet and would appreciate being enlightened on these. Disadvantages I see by using septic tanks at the household to intercept the solids, include:

• a costly problem (sludge) that needs to be dealt with later;
• unnecessary generation of greenhouse gases. At this scale utilisation of methane gas is unlikely; and
• Using a septic tank for intercepting solids is effective but costly. A small "interceptor tank" would require regular removal of sludge, which inevitably will not happen.

So far this doesn't come across to me as a sustainable solution at all. Details please...

I assume the idea is to reduce the cost of the sewer network. The tradeoff is between the cost of the treatment plant (per person) and the cost of conveyance (per person). Data please on the technologies considered. So will this then discharge to a waterway or to land? Context please.

Are the costs of installing and maintaining septic tanks outweighed by the reduced costs for conveyance pipes? I would suggest not. Well... perhaps for a while, but how long? Treatment plants have sufficient scale to (cost effectively) produce (adequately) treated solid and liquid waste. In this case, equipment would be required to extract the sludge from the septic tanks and an additional facility would be required to treat the sludge. Has vermidigester technology even been considered for interception? If not why not? This is by far the lowest cost option to remove solids from wastewater at source and produces easily handled humus rather than sludge. Paradigms fall slowly, from the weight of repeated failure... was this a lost opportunity for true innovation?

Dear Elisabeth and Dhwani,

The problem we had when we started the project that Kevin Tailor was the only person I knew who had any practical as well as knowledge of soem other interceptor sewer projects. The literature on this kinf of sewer network is very scarce. We did not find much information that was practical and provided enough details. I had work with Kevin in Palestine on a similar project 20 years ago, and in since that days few other project had been implemented. The advantages of this kind of sewer systems seemed obvious to us, but we could not answer the question why it had not been implemented more. As we are in the last phase of our project, we did not meet substantial reason (yet) why the system has not been tried elswhere.
Soon we will be able to share details of our project.
As for the toilet 'seats' we are looking for: Yes we are familar with the SatoPan. And I think that it is the best option for the Muslim community of Salamba (Tamale) where we laying the network. So far we did not find pour flush toilet in Ghana. But we would be glad to find them.

The project serves 3000 people (including a school with 1000 pupils and vocational school with 350 resident students). More on the project can be find on www.viawater.nl/projects/ghana-settled-s...k-sakasaka-in-tamale. The project information needs to be updated and that will happen soon.

The assumption we are testing is: a ventpipe vertically connected on the sewer pipe from thetoilet to an interceptor (or septic tank) will allow you to install scat pans / toilet without water-lock / stench trap (goose-neck). If anybody can confirm that (or not) based on experience we would appreciate that.

Dear Gert,

Since you are implementing this project you must have researched on it before.
Request you to share few case studies on settled/solid free sewer.
I would like to know more about it in detail.

Dear Elisabeth,
It will be really helpful if you also share few case studies on it.

Thank you.

Regards,
Dhwani

Hi Gert,
Welcome back to the Forum! In my role as moderator I try to ensure that no post that should be answered is left without an answer... For this reason, I have moved your two posts into this new thread as I think they belong together.

You wrote:

Where can we find (in Ghana) equipment to serve our purpose.

Which equipment do you mean? Do you mean pour flush sitting or squatting toilets? Maybe with the SaTo pan which appears to be quite popular these days? Have you already found what you were looking for?

And which design assumptions exactly did you need feedback for?

Also, which project is this, what is its scale and how is it funded? I see you are now a Senior Advisor with Daily Business which is established to support Bottom of the Pyramid business development for urban sanitation and waste management in fast growing cities. (according to your LinkedIn profile). Is that a consultancy firm?

Regards,
Elisabeth

Dear Kevin, (and others)
Sorry for not being in contact since we started to construct the WWT and network in Tamale (Ghana). The project is moving slowly but steadily. We added a ABR between the settling tank (which we changed in to a septic tank, and the aerobic filter that we concluded later work very well. So we decided to clean it and change the filter media with bettre local material; vulcanic rocks and plastic scrapnel. It running at its full capacity (40 m3 / day) and we started to test the effluent quality. We estimate that the WWT will be abel to serve about 6000 people.
More than 1,5 kilometer of small diameter (though we remained conservative) have been laid and we started to connect households.

As you predicted the willingness to connect imprive very slow, but now peoople can show neighbours the system and the opotion to connect the existing septic tanks help a lot. Yes, it remains a challenge, but the PerfSan teanm has been was strengthened by a clever female collegue with to work with the families and she is doing well.

The other challenge is the minimize the water use. As you might have seen in an other posting today we are looking for pour flush option.

During breakfast today, we came came up with the following assumption which we hope to get feed bak on from the SUSANA community.
The influent into the interceptor tank (adapted water polytank) is a 90-elbow. The pipe from the toilet to the interceptor has a good ventpipe (4 inch, 2-3 meters high). See images.

We assume that the ventilation will allow us to install scat pans / toilet without water-lock / stench trap (goose-neck).

In Tamale (Ghana) we are working on a solid free sewer network in a low-income area in the centre of the city, Salamba and Sakasaka. We build / renovated a waste water treatment (septictank, ABR, trickling filter) for about 6000 people (including 1000 school children and 350 school resident students of a nursery school).
Last month we are started to lay the small diameter sewer lines and are making the first connections. 1,5 kilometer of sewer pipes have been manually laid within 3 weeks with unskilled labourers.

SDoon we we will be posting a report on our experience. The project partners are PerfSan Ltd (Ghana), Daily Business/WASTE (The Netherlands) and GMB (The Netherlands). The project is partly funded by ViaWater.

The WWT has an capacity of 6000 people IF they use 1 liter water per flush. People are happy with that, because of the water shortages and price. We have under estimated the supply of pour flush options: scatting pans, soft S traps etc.

Where can we find (in Ghana) equipment to serve our purpose. We are also open to use solutions that we have to make from existing other materials.

Gert