Adaptable methods of emptying septic tanks in areas where de-sludging infrastructure is still not available
Does anyone know of alternative methods / solutions of emptying Septic tanks that could be adapted in remote areas where the de-sludging facilities are not yet available or areas that are inaccessible by emptying trucks? Looking for examples / suggestions.
Hi Sanjay, there's a few possibilities indeed. The ecompendium of sanitation systems and technologies describe a range of possibilities, and usefully includes not only pumping tools but also transport and disposal / treatment / reuse, which can often more critical than pumping out.
In very short, on the pumping side, the MAPET has largely failed; the VacuTug is used in Mozambique and I think in Bangladesh but it's often commercially unviable due to very low speeds. The Gulper is the fashionable pump at the moment, being very low-cost and easy to use, but still easily blocked by solid waste in pits. A new version, the Rammer, is being developed by Water for People.
There's a few other pumps (eVac, nanoVac...) being developed, see this story. However transport of sludge remains a big issue: if a tanker can't access, then a normal truck often can't either, and carrying 200-litre drums of sludge isn't an easy task. We in WaterAid have tried motorised tricycles in Tanzania, and Water for People has tried different options in Malawi and Uganda, but it is still what hinders the business model.
Also, many pumps / systems are being designed for latrine pits rather than septic tanks, which have a more liquid content.
when do you expect the required infrastructure to be available? Do you think it will ever happen?
In which case does it make sense to think about conversion of the existing septic tanks? Do these tanks have leach fields or are they closed? If not, does it make sense to convert these septic tanks with leach fields?
Or to convert them into composting toilets/installations?
I work for Water for People Malawi and agree with Remi - its the transport that's usually the killer.
Mind you, in very rural areas you may have better disposal options if you can cordon somewhere off as a composting site of sorts or just empty the latrine, dig a new pit for the waste and keep the superstructure intact.
We are working on a new version of the Gulper, called a Rammer...and we have also just imported some eVacs from PID South Africa.
Happy to share specs for Gulper/Rammer.
Hey Sanjay ;)
Even though I shared this already with you in person, for future reference:
http://desludging.org/ (simple septic tank sludge pump developed by Oxfam in Indonesia)
Have not tried it myself, so no direct endorsement, but it seems reasonably good for relatively liquid septic-tank sludge (as others have noted, most other manual pumps are designed for much more difficult pit-latrine contents).
However this really does not solve the issue of how to transport and where to dispose, and given the high water-tables around here (Leyte, Philippines) a simple drying and percolation trench seems like an unsuitable approach.
Normally I would construct a planted sludge drying bed with a sealed bottom and a secondary effluent treatment system, but this is really out of the scope of our current project.
even though the idea of re-utilization of human excrement is not (or seems to be) part of what you are looking for, I think the concept is worth a consideration. It reduces the need of handling, transportation and disposal:
An additional thought is the Arborloo latrine.
Human excrement as compost is not a common idea and often frowned upon by communities but it does have great benefits. Particularly making use of a resource that people generally spend way too much money and effort disposing of when it can be a great asset.
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