There's so many factors to consider when it comes to trash in pits, so I'm glad to see the discussions around regulation, incineration, enforcement, behavior change around SWM and FSM... 

If you are curious to learn more about the Excluder , please join our webinar on December 9th (8:00 AM US EST/ 1:00PM GMT/ 4:00PM EAT/ 6:00PM IST).

Register: www.eventbrite.com/e/learn-about-the-exc...tickets-217167773657

We will discuss how the Excluder operates and the market opportunity for the device across different global regions.

We hope to see you there.

Thanks for the topic, *How to deal with trash in pits.* Just off hand, incineration should be an option, taking care that, 1. What should not be burned is sorted out, e.g., plastics and what is hazardous. 2. The incinerator needs to burn cleanly, not polluting.

Local bricks can be made to build an incinerator, preferably insulating bricks. What can be burned cleanly may be suitable as briquetted fuel. There is no need to cut down trees for fuel wood.

Part of this topic might also be *medical waste disposal, * the same suggestions applicable. In this case the hazardous medical waste, properly sorted, could be encapsulated in a simple glass and stored in steel lined containers. I.e., not disposed of per se, but stored.

The biggest challenge may be in sorting the waste for it's proper disposal or storing. Someone needs to know how to do this and to feel motivated, i.e., to be properly compensated.

Angela, I am glad you opened up this topic to a whole other avenue on how to deal with trash in pits. There is definitely more to consider as one thing depends on the other.

I have edited the subject of this topic to include laws and enforcement opportunities in dealing with the issue of trash in pits. I wonder what other experiences exist from across the Sub-saharan region. From the places i have visited, mainly the larger cities of (Kenya, Uganda, Tanzania, South Africa) the narrative at face value seems to be very similar to our Lusaka, Zambia situation.

Kr

Hi Chaiwe,
The City is currently working with the community Based Enterprises in these peri urban communities to improve the Management of solid waste.  Enforcement has continued to be a challenge. However, in order to improve service delivery, the Local Authority has started decentralizing the operation of Public Health Services. Mini offices have been created in the Constituencies in order to improve Public Health services. These include, enforcement and Sensitization. The city is working with Lusaka Water and Sanitation to ensure  there is an increase in services for Fecal Sludge Emptying.  Currently ,there are less service providers in this Sector. As we enforce the Regulations, It will be important to have a well coordinated and available Fecal Sludge Management System in Place. Some communities are willing to have their toilets serviced unfortunately the service providers are not readily available. The cost for emptying is also said to be high.  The current service providers have a challenge with the existing designs for toilets hence the By - Law will develop  guidelines on what type of Sanitary facility will be suitable for different area for the protection of underground water. This cause for a complete System to be in operation in order for enforcement to create impact. 

Hello Angela,

Glad that you have shared these progressive insights into Lusaka City Councils' work. 

The development of the By-law is a step in a very important direction for the sanitation sector in Zambia. Addressing the issue of Solid Waste in pit-latrines/ toilets by charging fees for waste found in facilities during emptying is an intervention that helps ''nip this disposal behavior in the bud''. However, i strongly believe we need to pay attention to other things that enable this  behavior,  such as lack of adequate waste disposal systems and services, particularly within informal communities. The lack of/ limited opportunities for enforcement of laws also fuels the problem.

Following the finalisation of the by-law, how does the Lusaka City Council plan to improve enforcement of the law? Would really love to hear from you Angela.

Regards,
Chaiwe

This is good. Dealing with waste in pits has been a challenge.  Having to charge owners an extra cost will bring about behaviour  Change. As Lusaka  City Council we have been working on the Online Sanitation  and Fecal Sludge Management  By Law. Issues  of Trash were brought up. it was resolved  that a fine be put to households that will be found disposing waste in pits. The By Law has not been passed yet. Still at approval  stage. We are also working on improving  solid waste management. We realised that as long as there is no improvement  in the management  of solid waste, the community will continue the practice  of throwing trash in the pit -Latrines. 

Thanks for posting!  A very interesting and important research pathway.

Hello all,
We have been developing the Excluder- an attachment head that can be connected to a vacuum truck, a vacuum drum system, or a sludge pump. The main concept is that designing a mechanized system for pits with lots of trash is really difficult. Grinders, macerators are too energy-costly. Fishing is time-consuming and is another exposure pathway for pathogens for the workers and the community.

Trash exclusion is already being done with typical filters or screens at the end of a hose, but the screen will not work for a long time against plastic bags, etc. We have tested a variety of configurations, and found that an external auger is best at keeping the screen clean for the amount of time needed to empty a pit (1-2 m3). 

The paper has just come out- see attached. It's open access, so feel free to distribute. Thank you!

pubs.rsc.org/en/content/articlelanding/2021/ew/d1ew00383f


-Francis

Hello Hajo,

Thanks for the inquiry, and I apologize for the late response.

You are correct; there are two technologies. The Flexcrevator is a pit-side vacuum system that incorporates a trash excluder. The Flex-X is the trash excluder designed to attach to any vacuum system (such as a vac truck). The idea is to continually push the trash away while vacuuming the faecal sludge, thus leaving the trash behind. Thank you of r your comments about trash exclusion. We have tried various methods for dealing with trash: screening, maceration, and they don't really work or require lots of energy.

1. The next phase of the project is oriented toward commercialization. This project is funded by the Bill & Melinda Gates Foundation, and hopefully we will have the continuation funding to get to "engineering validation" units. The plan is to test the Flexcrevator and Flex-X in the following countries: Malawi, Zambia, South Africa, Senegal, and Rwanda.

2. The fluidization approach in Malawi is probably the way to go. We are hoping that we would only need to fluidize to make FS movable with vacuum, and not fluidizing to make trash float or be easier to remove. So hopefully we would need less water if the FS is too thick for vacuum.

3. With the Flex-X, other pumps can be used (trash pumps, centrifugal pumps, diaphragm pumps). However, as you noted, a typical centrifugal pump would need more watery sludge. We welcome local solutions that are appropriate for the area- if a certain region has watery sludge with lots of trash, then they can use whatever pump works, and attach the Flex-X.

We will send updates on this forum when we have things to report. We welcome any comments, ideas, questions! Thank you again.

Regards,
Francis

+++++++++
Note by moderator: More information about this technology is available in this thread:
forum.susana.org/99-faecal-sludge-transp...hnology-flexcrevator

Thank you, Elisabeth, for directing me to the link... possibly should have found it by myself...

dear Francis,

I like the FLEXCREVATOR and the idea of trash exclusion, makes pit emptying easier (possible) and may serve educating people not using pits as solid waste dump.

I noted that the FLEX-X is a variation of the FLEXCREVATOR where it only serves as a 'trash excluder' while the pit emptying is done by a separate vacuum system.

I have a few questions:
1 have you made any progress in improving both systems as indicated in your presentation at FSM4 towards 'commercialisation'?
2 The problems of pit emptying are not only the trash but also the consistency of the sludge. Are you working on solutions for fluidisation when the sludge is too dense for vacuum pumping?
3 Is it necessary to have a (presumably more sophisticated) vacuum pump stationed near to the pit if it could be replaced with a 'simple' dewatering/sludge pump? Of course under the condition that trash is excluded and sludge be fluidised to the 'right' solid content. I like the 'simplicity' of the trash exclusion technique and like also to have a 'simple' pumping mechanism. If a 'dewatering' pump is placed near the pit, the 'pressure' distance from the pit to the sludge 'tanker/container' is more easy to handle with pressure than with suction. And if the pump is close to the pit, the atmospheric pressure may be sufficient to suck sludge from 3-4m depth.

looking forward to your comments,
ciao Hajo

I look forward to reading more from Francis about this here on the Forum, too (thanks for posting your paper here, Francis!).

I had a look at the FSM4 Conference page within SuSanA and found his presentation here:
www.susana.org/en/resources/conference-m...-india-february-2017

If you use the ctrl+F function and search for "exclusion" you find it here:

WEDNESDAY, 22 FEBRUARY 2017, 2:30pm – 4:00pm

RESEARCH 3.4: Pit Emptying & Sludge Accumulation Rates [Audio]

1. DE LOS REYES, F. et al.,“The Flexcrevator: An Improved Pit Emptying Technology with Trash Exclusion”, USA

Direct link to presentation: www.susana.org/_resources/documents/defa...883110.%20et%20alpdf

there is also a link to an audio file for the whole session:
www.susana.org/images/audio/Day3_Research_3_4.mp3

(are people finding the audio files convenient? If yes, it could be a good alternative to posting videos. Perhaps something to listen to during long boring train trips )

For new people I would like to point out: Francis' earlier research used the nam "excravator" - previous forum thread here:
forum.susana.org/99-faecal-sludge-transp...sa-now-field-testing
(note 4 pages of discussion)

hello,
I read your posting on the above topic but could not find any further documentation of the Flex-X presented in Chennai at FSM4.
Could you either send me a link or let us know where you stand with regard to trash exclusion which I find a very useful approach.
ciao
Hajo