SuSanA - Forum Kunena Site Syndication Wed, 23 Jul 2014 01:14:59 +0000 Kunena 1.6 SuSanA - Forum en-gb Re: re.source: Mobile Sanitation Services for Dense Urban Slums (Stanford University, USA) - by: snghosh i have enjoyed your discussions about this toilet and business around this. I would love to know your experience about the relation between acceptability of this toilet and culture of people or communities where you apply this. Especially in rural India, it seems quite heard to push such toilet as people do not want to see their shit after they leave. There are two key aspects in rural areas which play big role in sanitation behaviors and application of technologies. People who have place in house always want permanent toilet of their won. These people look for two kinds of design (1) septic tank and (2) pit latrine. The pit latrine ( twin pit) are good as it decompose on site and likely to be sustainable mainly for areas where water table is not high and not flooding. it might be similar to many other countries. the other thing that people do not like in India is dry toilet as the culture is using water after defecation. I think toilet in rural areas ( like India) only when majority of people have toilet and do not allow the poor to defecate in their land. In such social pressure poor have no choice other than such toilet.
i see the chances of trying this in India is in urban communities where people do not have space at all in home for constructing toilet, neither they can go out for defecating. i also would love to know your experience in reducing the cost of this toilet if it is made of fiber. In urban areas, the business could be around collection and transportation if it is mechanical in India. It needs to be completely mechanical here in India because the low against manual scavenging.


Faecal sludge transport Tue, 22 Jul 2014 16:59:39 +0000
Re: re.source: Mobile Sanitation Services for Dense Urban Slums (Stanford University, USA) - by: DavidAlan
We are currently doing the same thing in villages with single chamber UDDTs and a collection service, but it is too early to discuss the sustainability.

As for the units, we currently have an urban (slum) system that doesn't give us the life/cost ratio we want. We are trying to get the price down to $300 with a life cycle of 30 years, and are working on a 'virtual' final design as I write. Our model is self-sustaining over this kind of life-cycle.

We will have more information later this year or early next.]]>
Faecal sludge transport Tue, 22 Jul 2014 07:33:03 +0000
Re: re.source: Mobile Sanitation Services for Dense Urban Slums (Stanford University, USA) - by: stevensugden
Black Solder Fly - I recently heard from elsewhere that they prefer other forms of organic waste to shit, and who can blame them?

Cost of unit production - seems to be recurrent issue and I wonder if the wooden / concrete versions have the same appeal. We really need to agree on one design and then approach a single supplier and encourage them to invest in a mold. They usually talk in selling 10s of 1000 of units to enable them to recover their mold costs, so even if we got together, it would be a hard sell. Tim at Envirosan in South Africa may be interested and the may even have an existing design which could be used.]]>
Faecal sludge transport Tue, 22 Jul 2014 07:24:33 +0000
Re: re.source: Mobile Sanitation Services for Dense Urban Slums (Stanford University, USA) - by: CeciliaRodrigues
Thank you all for this very interesting thread. I am learning a lot from it.

@Kory, I watched the video of your presentation at the webinar and there you mentioned that you were considering other treatment technologies and back-end products besides composting, such as the DEWATS and biogas. I am wondering how your research evolved in this regard. Would that be technically feasible considering that you are adopting UDDTs? I suppose you are using sawdust or some other dry material, wouldn't that interfere in other treatment processes?

Kind regards,
Faecal sludge transport Tue, 22 Jul 2014 05:25:05 +0000
Re: Sanitation Community of Practice Workshop - WISA Biennial Conference 28 May 2014, Nelspruit, South Africa - by: SudhirPillay on behalf on Mr Jay Bhagwan on the Sanitation Research Fund for Africa project, a joint initiative between the BMGF and the WRC.]]> Faecal sludge transport Tue, 10 Jun 2014 09:04:09 +0000 Re: Video of interview and demonstration for excravator - power auger to empty pits - by: twrogers Pits with trash pose several challenges for emptying. For the "Excrevator", fibrous materials such as bags, rope, hair, etc. can get caught in the auger and cause jamming, which leaves us with two main options:
1) Put a screen around the inlet to prevent objects from entering
2) introduce a cutting device at the inlet to reduce the size of the material coming in to a point at which it can move up the auger.

The difficulty with option 1 is that often the sludge in the pits does not readily flow, so it would not pass through the screen or make it into the auger. If the sludge does pass through the screen, then your faced with the problem of trash clogging the screen and preventing flow into the auger.

The cutting designs we are currently working on here at NC State, would connect directly to the end of the Excrevator. The blades will shear materials that pass through it to sizes that will flow easier through the auger in addition to mixing the surrounding sludge to make it flow easier into the auger. Larger trash items such as shoes, large rocks, etc. would not make it into the auger and can be removed manually after the sludge has been removed.

In regards to having small pieces of trash mixed in with the sludge, this will be more or less of an issue depending on the downstream treatment process. Some technologies (like the LeDePa I believe) have a screening process on the front end that can remove trash before treatment. Also, if the treatment process involves some sort of combustion the trash may not be a big issue. Another option may be to have a screening process at the outlet of the Excrevator to separate the trash and sludge before transport.
We are early in our cutting technology development and will know more about the feasibility of the design after testing in South Africa in July and August.

As mentioned in the webinar, the best comprehensive solution for trash in pits is to design the toilets or to incentivize the users so that trash is never introduced to the pits. Programs like the one in Ethekwini have shown a significant reduction in the amount of trash found in the pits. Hopefully, in the near future trash will not be a huge issue, but currently it is a problem that needs solving for pit emptying technologies.

Tate Rogers]]>
Faecal sludge transport Mon, 02 Jun 2014 19:45:35 +0000
Re: Modernising urban sanitation in Southern Bangladesh (SNV) - by: sahidul93 Thanks,]]> Faecal sludge transport Tue, 13 May 2014 14:43:23 +0000 Re: Video of interview and demonstration for excravator - power auger to empty pits - by: muench

The Playlist list for the entire webinar is here:

The video includes the presentation as well as a question and answer session which I briefly summarise below (the questions start here in the video:

Arno asked how the Excravator deals with the solid waste (trash) that is in the pits of VIPs (or any pit that doesn't have a water seal on the toilet), since people tend to use the pits also as a general rubbish dump?

Answer by Francis: One aspect is education to teach the households to throw less trash in the pits (example eThekwini Municipality) (my own addition: or to give them alternatives for solid waste collection).

But in terms of the Excrevator: what enters the auger, normally gets pushed up due the rotational force. They are working on new designs to cut the trash by using the rotational power from the hydraulic motor - to "slice" the materials. So it should be able to handle some trash; they are experimenting with how the auger can deal with ropes and fabrics. But some other larger trash items will be left in the pit and it is then perhaps easier to take that out manually (once the rest of the sludge is gone).

--> follow-up question: a disadvantage of cutting of the trash is that you end up with e.g. small pieces of plastic mixed into your faecal sludge which will could reduce the reuse potential of the faecal sludge (in agriculture). From that point of view is it perhaps better to leave the trash as larger pieces would could be removed at a sorting facility of some sorts later?

I asked how easy or difficult it is for a professor in the USA to do research on pit emptying and what academic twist (research questions) can be put on it.

Francis highlighted that the "currency" of academics everywhere is publications and results. When you dig deeper into this topic (pardon the pun!) you realise how many open questions and knowledge gaps there are about the details, and this gives room for scientific publications. It gets more exciting the deeper you dig.
Research questions: Mechanical properties, operation, design, how people would use the tool, keeping the costs down --> it all becomes quite a challenge.

The students are actually very keen to do work on developing countries issues. It's not glamorous work but the students enjoy the challenge of this type of work

One problem is that it is very hard to simulate the pit content and pit empyting in the lab! The key is to go out in the field and to iterate in the field and that's what they will do this year. For example: How do you standardise trash content in a VIP pit (collaborationg with Uni UKZN in Durban, South Africa) - pit contents will be different in India to South Africa, differences for toilets with water seal (pour flush) to toilets withoug etc.

Question by Brian: you are working on cutting technology for the input solid waste to augers, is this something you would collaborate on with other grantees (like with us)?

Answer by Francis: "Yes, sure. We have a new design that we are testing in the lab, we feel that we can harness the rotational motion and power of the auger for cutting. The auger will hopefully also change a bit the quality of the sludge and the size of particles as the faecal sludge passes through the auger during the pit emptying. The input of energy will alter the sludge characteristics."

In the general discussion video, Francis was asked again by Mutala about source separation, i.e. how to get less trash in to the pits.

You can listen to Mutala's question and Francis' answer here:
The answer to this question is more or less the same as given under Point 1 above.

The general discussion video for the entire webinar is here:

I hope you found this useful and I am curious to know what other people who are working in the field with similar devices think of the Excravator? Sounds great but too expensive in practice? Or price OK, but too difficult to operate? Or all great? What are your thoughts?

Faecal sludge transport Mon, 12 May 2014 16:06:30 +0000
Re: Low cost innovative technologies for Pit Emptying - by: willychipeta Faecal sludge transport Wed, 07 May 2014 13:26:38 +0000 Re: Measuring the physical strength of faecal sludge/pit latrine contents - by: muench
I only found this photo in your presentation from last year, but am not sure if it is representative?

I found it in this presentation:]]>
Faecal sludge transport Wed, 07 May 2014 12:41:10 +0000
Re: Kampala Sanihub Project (Uganda) - by: gdrum01
Let me respond on behalf of Cate. My name is George, and i'm a sanitation engineer managing WFP's Sani-Hub project in Uganda. In answer to your questions:

1) Our review of policies on FSM found that most of the existing policies are outdated and poorly enforced. With regards to involving decision makers, we see our role as to prove the benefits of the market driven approach to sanitation, such that the policies can then be reviewed and updated, which should attract more entrepreneurs to sanitation as a business.

2) While developing improved pit emptying devices, we have worked directly with existing pit emptying operators to better understand the operation, the limitations of existing technologies, and how the techology can be improved. The rammer (gulper 2), is an example of this. It can pump thicker sludge and reach deeper into the pit, thus allowing businesses to expand their customer base. We have also developed a chain based pit emptying device, however, development was halted due to the range of challenges, most notably dismissal upon showcasing the device to existing operators.

3) We are developing a pit emptying equipment leasing model which will be geographically tied into a pilot DEWATS treatment plant. This model should prevent illegal dumping as the equipment will need to be returned with full barrels of sludge, which can then be loaded into the DEWATS. The DEWATS has a gas meter to measure biogas production but we are still considering our options regarding productive use for energy generation. The pit emptying business model is financially sustainable, but because the pilot DEWATS is still under construction, we are still considering how it can become a business model in itself. This, I think, will be our biggest challenge.

Faecal sludge transport Wed, 07 May 2014 07:45:18 +0000
Re: Develop new innovation for pit latrine emptying in peri-urban Mzuzu - by: gdrum01
I am currently working as a sanitation engineer for Water For People Uganda, and we are also funded under the WRC/SRFA grant (see here: Our latest desludging tool - the rammer (gulper 2) - is currently being field tested. It's advantages over the gulper are that it is extendable (reaches deeper into the pit), and because the moving valves are submerged, it pumps thicker sludge. Furthermore, the device uses a donkey tail, so is not so strenuous on the arms as direct lifting. The design improvements were made by interacting directly with pit emptying businesses in Kampala.

Technical drawings of the rammer can be found on our blog:

Alternatively we can ship these devices across Africa if you'd like to test it and provide feedback and insight.

We have also tried developing chain based devices, however, this work stopped due to the variety of challenges we found - rusting of the chain, cleaning after use, weight, the fact that thicker sludge is at the base of most pits but the device is not extendable.... we held a feedback survey with pit emptying operators and they dismissed the device immediately.

Faecal sludge transport Wed, 07 May 2014 06:40:18 +0000
Re: The Fecal Sludge Omni-Ingestor (FSOI) suite of technologies (several companies, USA) - by: awhitesell Faecal sludge transport Mon, 05 May 2014 17:01:44 +0000 Re: The Fecal Sludge Omni-Ingestor (FSOI) suite of technologies (several companies, USA) - by: awhitesell
The Manual Pump is a low cost pump designed for use by manual emptiers with the main objective of allowing them to empty vaults in a more safe and sanitary manner. It was designed for emptying relatively shallow vaults (2 meters) and pump material with a solids content below 10%. As of yet, I don’t have any empirical data about the shear strength of the simulants that have been used but we have mixed up some pretty thick material. I’ve used the pump with actual septage and can pump at 1 liter/sec easily and at 2 liters/sec with some effort. I’m working on a third generation design and expect to have prototypes in the field in about 4 months.

There are 3 different powered pumping solutions being developed. The one demonstrated in India was designed for emptying septic tanks having a TS below 5%. The shear strength of what has been pumped hasn’t been measured but I think we can pry an estimate from Jamie Radford, who is consulting on the project. It can handle septage that is loaded with debris and grit, and can pump it greater distances than most vacuum trucks. The other two pumps are still being designed or manufactured. Both of them can handle material with a TS of 40%. All three can pump at a rate of at least 3 liters/sec.

The three powered-pumps are all entering intensive domestic field-testing in the next few months. They’ll be independently tested by waste management companies that will use them in their day-to-day businesses of emptying residential, commercial, and government septic tanks and out-houses. Following the successful completion of that testing, one of the pumps will move on to foreign field-testing.

Over the last 2 years, many simulants have been used and we’re still refining the recipes. They’ve varied from the simple (bentonite and water, kaolin clay and water) to the complex and costly. But, for the most part, they have been homogenous mixtures, not weak mixtures with TS values exaggerated by adding gravel or dense material. We also have a long list of extraneous matter that can be added to the sludge to make it extra challenging. Within the next 8 weeks, when the ingredients are settled upon and the instructions for producing them and testing them are finalized, we’ll be sharing the information online.

One of our directives was to develop a pumping system that would make emptying the vast majority of the vaults in the developing world possible. This presents two big challenges. First, the pump must be capable of pumping a wide range of sludges. Shear strength, density, plasticity, stickiness, debris types and quantities, and grit types and volumes are just some of the factors to account for. Second, the pumping systems need to reach the vaults. GIS data and custom algorithms were used to determine the hose length needed to reach 90% of the pits in African urban settlements and the results were verified with ground surveys. It was determined that about 92% of the vaults in Africa could be reached from the nearest drivable road by a 50 meter hose. The survey work also drove the design requirements. Path widths, roughness, turn radii, incline, road types, road-to-vault distances, weather conditions, soil type, door width, ceiling height, access hole size, hose types, and vault dimensions are a few of the variables considered.

This is an exciting time for those of us working on the Omni-Ingestor project as we’re entering the field-testing phase, getting closer to having a commercial product, and the work is getting more public exposure. We’ve been pretty quiet up till now and RTTF India was the first time we really publicly shared information about the equipment being developed. It was fun talk to people about the OI and answer their questions. So thanks for your questions and I’m happy to answer any more you might have.


Andrew Whitesell, USA

p.s. I've attached a short video showing one of the simulants.]]>
Faecal sludge transport Mon, 05 May 2014 16:39:39 +0000
Develop new innovation for pit latrine emptying in peri-urban Mzuzu - by: kusheliwa Faecal sludge transport Sat, 03 May 2014 08:26:29 +0000