SuSanA - Forum Kunena Site Syndication Sat, 28 Nov 2015 05:52:59 +0000 Kunena 1.6 SuSanA - Forum en-gb Re: Interesting discussion on scheduled desludging vs on-demand desludging on Urban Sanitation and Hygiene dgroup (SNV) - by: muench
Thanks for mentioning this discussion on Dgroups on scheduled desludging versus on-demand desludging of septic tanks.
We've also had quite a lively discussion about this topic here on the forum in the past:

So I think quite a few people in the SuSanA community are interested in it.

I will ask the organiser of that Dgroup discussion (Antoinette) if she can copy the posts across to here or post a summary of the discussion here. Copying posts 1:1 would be good but may not be feasible without asking each contributor for permission as the Dgroup is a closed group whereas the SuSanA discussion forum is an open group (some people may not like to have their contributions in the open arena which we need to respect).

Faecal sludge transport (including emptying of pits and septic tanks) Fri, 27 Nov 2015 08:47:20 +0000
Re: Modified treadle pump (pit pump) prototype - peddle powered gulper modification (Malawi) - by: awhitesell
How is the pump development going? I've been working on the design of a manual pump myself. I had a prototype of it at the toilet fair in India last year. There are some videos on the site that you can search for if you want to see what it looks like. I'm just finishing up a new design of the pump and over the next few months will be refining it. I'll post some pictures when it is ready.

Early on in the development of the pump I explored making it pedal powered. I liked the idea of riding up to a pit, engaging the pump mechanism and pedaling the bike to power the pump. I also looked at a pedal powered pump that was not integrated with a bike. It proved to be too complex and the mechanism wasn't ideally suited for pedal power. I may revisit the mechanism at some point but for the moment I'm going with arm power.

I watched your video and have some thoughts. Without actually working with your pump or at least seeing your detail drawings it's a little hard to evaluate but maybe this input will be useful.

1. The longer your stroke length is, the more efficient your pump will be (to a limit). The reason for this is every time you change direction, your one-way valves (check valves) need to open or close. Every time the are opening or closing, they are reducing your efficiency as material slips past them or they don't serve their purpose. If your cylinder were very short, the valves wouldn't have time to actuate. So the longer the better...

2. Except that you don't want a stroke length that exceeds the range of motion of the human providing power. More specifically, you don't want the stroke length to exceed that which the human can transmit through the mechanism when the human is keeping their stroke to the most efficient range. With arm power, at least on my pump, I consider that range to be about 20 inches. With leg power it might be 8-16 inches depending on the mechanism.

3. Since you are using pedal power, it's easy to argue that the ideal stroke is what a conventional bicycle has, after all, the geometry has had 100+ years to evolve and it hasn't changed much since early on. The next thing to define is the mechanism that converts your rotary petaling motion to the reciprocating motion of the cylinder.

4. Something to keep in mind while designing your system: the diameter of your piston (the bore) is important. The bore and the stroke are going to have a big impact on how much power your system needs and the design of your mechanism. You don't want the bore to be too large as the human powering the system may struggle or you'll need to gear the system. I suggest keeping the system as simple as possible so you'll need to carefully select your bore and stroke. My arm powered system has a bore of 70mm or so.

5. Another consideration is the design of the piston and the seals. Poor seal design will result in fluid or air getting past and a decrease in efficiency. Or, the seals will produce too much friction and require more power - the operator is going to get tired quickly.

6. You also need to prevent the piston from pivoting in the cylinder. If it pivots, it seizes. The design of the piston plays a part in this and so does the length of the piston rod. Ideally, the end of the piston rod will only experience vertical motion but that isn't necessarily practical. This is one of the very nice things about a two piston treadle pump; the piston stroke can be purely vertical. Anyway, you'll want to design your mechanism to reduce how much the piston rod and piston pivot. One way to achieve this is to maximize the distance between your rocker pivot point and the point where your piston rod attaches to the rocker. The "rockers" on your 2nd prototype are the 2 bars connected to the sprocket above the pump cylinders.

7. You should also try and get the point where the piston rod attaches to the rocker to be directly above the cylinder. You don't want it being off center throughout it's entire motion.

7. You mentioned that you are using a motorcycle chain instead of a bicycle chain because the bike chain was breaking. If the system is designed well, and the chain is properly aligned, a bike chain should be sufficient. I suspect you didn't have the chain rings / sprockets lined up. Or maybe it was a chain quality issue. Looking at one of the pictures, it seems that your piston rods are attached to the chain. Is that right? If so, I'm not surprised the bike chain broke, they really don't take side loads well. The approach you took in prototype 2 seems more sound.

8. What type of valves are you using?

9. Lastly, you are right. 2" diameter hose presents problems. We tested various sizes over the course of the Omni-Ingestor project and 3" seems like the right compromise.

Good luck with your work.


Faecal sludge transport (including emptying of pits and septic tanks) Sat, 07 Nov 2015 15:00:38 +0000
Re: Modified treadle pump (pit pump) prototype - peddle powered gulper modification (Malawi) - by: muench
You have probably in the meantime already connected with Nicola by e-mail. But in case not (and in case other people also don't know): Any forum member can contact any other forum member by using the "message" button which you see to the left of the person's post (you need to be logged in to be able to send your message).
Therefore, there is no real need to ask for someone's e-mail address.

If you want to make it even easier for people to contact you, you can also add your own e-mail address in your forum signature. An explanation on how to do that is provided here:

Kind regards,
Faecal sludge transport (including emptying of pits and septic tanks) Fri, 30 Oct 2015 13:15:07 +0000
ONAS Emptier's manual (looking for) - by: Xavier
Reading the "Boues Mag" n°4 from ONAS (Sénégal) I see that ONAS published a manual for cesspit emptiers.

However I don't manage to find it on the web or ONAS website.

It sounds to be a nice document with practical issues adressed to improve regulation of desludging activities.

Would someone know where to download this document ?

Thanks for advance
Xavier (Practica)]]>
Faecal sludge transport (including emptying of pits and septic tanks) Fri, 30 Oct 2015 04:23:14 +0000
Re: Kampala Sanihub Project (Uganda) - by: osbert I would like to share with you some of the activities that we have been able to do up to now. Kindly follow the Link.
Others in progress to be shared soon include Pit latrine life extender, BSF Progress, Scaling up of DEFAST,]]>
Faecal sludge transport (including emptying of pits and septic tanks) Tue, 27 Oct 2015 06:50:20 +0000
The Sludge Digger (a device I’ve developed for emptying pit latrines, septic tanks, and similar tanks) New Video - by: dandreatta
Some of my past posts have talked about a device I’ve developed for emptying pit latrines, septic tanks, and similar tanks. I’ve shared links to some preliminary videos, but here finally is a link to a proper video showing what the device can really do. It now has a proper name, and I’m calling it the Sludge Digger. The video is at:

If the link to the video doesn't work, one can do a youtube search for my name and find it easily.

The video starts with a long still scene while I narrate, but it eventually gets moving, and there is some comic relief at the end.

The sludge digger is a pivoting bucket on a stick, with a rope. It is intended to replace the direct use of shovels and buckets, while still retaining the simplicity of buckets. It can easily pick up just about any kind of trash in the sludge, and a wide range of thick or thin sludge.

The video shows prototype 3 or 4, in the attached still photo is prototype 5 or 6, with a much sleeker design, more durable and more suitable for production. Also attached is a manual for how to build the sludge digger.

My goal here is to keep people out of pits and tanks. This is only the first step of the sludge management chain, of course, but I think this device would fit well into a low-tech, low-capital system. In a village the sludge could be carted to a central waste management facility (possibly composting, or vermicomposting) using a human or animal drawn cart that fits through narrow streets if necessary. In a city the sludge could be carted to transfer stations spaced perhaps a kilometer apart (maximum travel distance for the cart therefore is 500 meters) then the tanks at the transfer station could be emptied by tanker trucks, which would carry the waste to larger facilities. If traffic were heavy, the trucks might only come during a time of day when the traffic is lighter. (On my trip to Chennai in August I gained a profound respect for how difficult the traffic can be in a big city.) If trunk sewer lines are present, perhaps instead of transfer stations, the carts could be emptied at selected inlet points to the trunk sewer lines.

The only down side to the sludge digger, in my opinion, is that it requires a hole of about 25 cm diameter to get into the pit. (Of course, to send a human into the pit would require an even bigger hole.) I am currently working on similar devices that will go in through the squatting hole, though these will probably only work in fairly thin sludge. More on this later, with similar videos coming in a few months.

Dale Andreatta]]>
Faecal sludge transport (including emptying of pits and septic tanks) Sun, 25 Oct 2015 21:50:19 +0000
Interesting discussion on scheduled desludging vs on-demand desludging on Urban Sanitation and Hygiene dgroup (SNV) - by: ggalli
I would like to draw your attention to the discussion on the urbsan dgroups mailing list which is currently being held. It's linked to an SNV learning activity around “Urban Sanitation – Professionalization of sludge emptying services”, but I'm sure contributions from other organisations are welcome. This week the discussion is on regularised desludging and there are quite some interesting contributions coming in from Indonesia and pertinent questions being asked from our Kenyan peers.

I'm not sure how to link SuSanA with this discussion, maybe one of the moderators can help here. Otherwise individual members can join the mailing list here: or by emailing: This e-mail address is being protected from spambots. You need JavaScript enabled to view it

Faecal sludge transport (including emptying of pits and septic tanks) Fri, 23 Oct 2015 08:18:24 +0000
Re: Survey for PhD research: Validate Business Model innovation of Faecal Sludge Collection & Transport Service - by: tahunganh
Thanks to your participation. My survey has about more than 200 respondents from around the world mostly from developing countries based on onsite sanitation system

We are on the way to analyse the data to confirm the result which components effect on the business success which can be share to you soon after is it peer-reviewed

In the meantime, in case you interested more detailed please discuss on the coming platform:

Engaging the Private Sector in Sanitation

Week 1 (26 Oct - 1 Nov) will focus on raising demand through sanitation marketing and financing options including access to household credit, financing local entrepreneurs, etc.

Week 2 (2 - 8 Nov) will focus on efforts to engage local entrepreneurs to respond to this demand. to lead on this topic looking mainly at local entrepreneur engagement around toilet construction and emptying.

Week 3 (9-15 Nov) will focus on the prospects and challenges of engaging the local private sector in transport, disposal and reuse.

Will back to you soon.

Faecal sludge transport (including emptying of pits and septic tanks) Tue, 20 Oct 2015 06:31:01 +0000
Re: Brief on pit emptying as a business - by: JKMakowka
I found the comment about the low demand for equipment very interesting (see also my comment in the other thread). I guess in many places the existing entrepreneurs are in a position were they are supplying a service to a small niche market and are not so interested in risking that market by scaling up their services.]]>
Faecal sludge transport (including emptying of pits and septic tanks) Wed, 07 Oct 2015 03:36:04 +0000
Brief on pit emptying as a business - by: rkaupp
The Stone Family Foundation has done a short brief on and attached, summarising discussions between WSUP, Water for People and WaterAid on our main lessons from pit emptying as a business on Tanzania, Malawi and Uganda.

Faecal sludge transport (including emptying of pits and septic tanks) Tue, 06 Oct 2015 15:23:49 +0000
Re: Solutions for pit desludging and sludge management in low income urban settlements in Malawi (Mzuzu University) - and policy issues - by: Daniel82
I write to share the progress made for my research work on investigating Faecal Sludge Management (FSM) Policy gaps in Mzuzu City – Malawi.

I did household surveys to determine the current FSM practice in the city. I discovered that over 50% of households did not own the residential premises which made it difficult for them to make decisions on the facilities. The city does not recommend any specific type of facility which leads to people just constructing any type. This coupled with distance to sludge ponds leads to varying costs of pit emptying services. Additionally, some households construct deep pits in areas with high water tables which risks contamination of ground water.

A review of government WASH related policy documents and Acts showed that they are disjointed as they are not clear as to which entity is mandated to do what and which one is responsible to enforce the guidelines. From the research work, FSM guidelines are going to be developed for the city basing on the already existing by-laws for solid waste management.
I therefore invite any input towards suggestions on what needs to be incorporated in the guidelines for FSM considering the background given. You may also wish to look at the paper presented at the 38th WEDC International Conference and comment. Follow the link below:]]>
Faecal sludge transport (including emptying of pits and septic tanks) Thu, 01 Oct 2015 09:33:12 +0000
Re: Lively discussion on 'fishing' of rubbish from pit latrines at WEDC - by: stevensugden
I think fishing is the elephant in the room with regard to the pit emptying process. There are a number of devices in development which can handle varying densities of sludge, but none is capable of managing the solid waste dumped in to pit latrine. Vacuum based devices no doubt have advantages in that they have no valves which can easily block as the waste passed through them.

I went fishing the last time I was in Malawi and it is hot, sweaty, physically demanding work. (We should have a rule that the only people able to attend FSM 4 are those who have fished out at least one latrine - that would help being a focus to the problem) The fishing process used a standard fishing tool and took 1.5 hours. It resulted in around 180 l of solid waste. After it was laborious removed, emptying the remaining 800 liters from the put took around an hour. It was mainly plastic bags, and cloth of varying sizes, and a large school bag. The argument that the pit latrine is important for the disposal of menstrual pads may be true, but the size of some of the cloth pieces and the size of the plastic bags would seem to indicate that this is far from the only source of waste.

Faecal sludge transport (including emptying of pits and septic tanks) Thu, 24 Sep 2015 07:43:29 +0000
Re: Lively discussion on 'fishing' of rubbish from pit latrines at WEDC - by: dandreatta
A preliminary video of the Sludge Digger is at:

The device has been made much more neat and compact since this video, small enough to fit through a 25 cm hole. As soon as I can get my company's video techncian to finish the new video, I will post a much better video. This should be in a week or two. This video will show the Sludge Digger being used in very thick sludge. Based on Jan Spit's statements at the WEDC conference, I believe this is about equal to the sludge he was unable to pump without being fluidized. As you will see, the Sludge Digger also picks up a variety of trash easily, since it is essentially a bucket on a stick.

Dale Andreatta]]>
Faecal sludge transport (including emptying of pits and septic tanks) Tue, 22 Sep 2015 20:21:03 +0000
Re: Lively discussion on 'fishing' of rubbish from pit latrines at WEDC - by: hajo
thanks for picking up my post and responding to it.. I am very curious to learn more about your Sludge Digger especially as you emphasise that it works 'without fluidizing, and without fishing out all the trash'. That sounds very interesting because I had learned from eThekwini that sludge which has been fluidized for pumping is too fluid to put it into the LaDePa. And I wonder how big trash can be so that the Sludge Digger can still handle it.

Looking forward to see your next posting,
ciao Hajo]]>
Faecal sludge transport (including emptying of pits and septic tanks) Tue, 22 Sep 2015 06:50:26 +0000
Re: Lively discussion on 'fishing' of rubbish from pit latrines at WEDC - by: dandreatta
Sorry for the slow response, I always seem to be 2 weeks late on my Susana reading.

I believe Jan is referring to me when he talks about lively discussion and alternative ideas. I had seen most of the content of Jan's presentation previously, on the Susana Forum and through links to the Hanoi conference in January (I attended the WEDC Conference but not the Hanoi Conference). At WEDC I asked a number of questions about how thick is the sludge before and after fluidizing, and the "alternate idea" that I proposed was my Sludge Digger. This is a low-cost alternative to gulpers, vacuum trucks, vacutugs, etc, which is under development and will be shared soon through the Susana network. Based on Jan's description of how thick is the sludge before fluidizing, I believe my Sludge Digger would pick up sludge without fluidizing, and without fishing out all the trash. Watch for a video in the next couple weeks demonstrating the Sludge Digger. The down side to my Sludge Digger is that you need a hole of about 25 cm diameter to access the pit. (A smaller version that goes through the squatting hole is also being worked on.)

I'll also mention that in the following part of the conference Steven Sudgen talked about how fishing trash out of a pit is a terribly filthy process.


Dale Andreatta,
Mechanical Engineer]]>
Faecal sludge transport (including emptying of pits and septic tanks) Mon, 21 Sep 2015 20:48:22 +0000