What can I add to a pit latrine to stop it smelling?

  • Angus
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What can I add to a pit latrine to stop it smelling?

Hello,

I am investigating what could be added to pit latrines to stop them smelling/make them smell of roses!

It's for some existing systems so UD isn't an option. They are completely sealed pit latrines and are desludged regularly.

I'm looking for anybody who has successfully used some additive in the past, knows of some additive that might work, or has some other good idea for stopping the smell?

Any help would be greatly appreciated,
Angus
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  • muench
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Re: What can I add to a pit latrine to stop it smelling?

Dear Angus,

(could you please introduce yourself, as it is your first post, or edit your profile, so that we know a little bit about you? Thanks.)

I can only tell you what doesn't work: commercial pit additives.
See here in the forum where have have discussed commercial pit additives quite in depth, mainly based on research from South Africa:
forum.susana.org/forum/categories/53-fae...l-sludge-includes-em

Mind you, there is research going on at the London School of Tropical Hygiene and Medicine which is also looking into pit additives. Maybe they are onto something that I am not aware of. See here on the forum and perhaps ask Jeroen Ensink on the forum:
forum.susana.org/forum/categories/105-pr...h-africa-and-vietnam

Other than that: what is the root cause of the odour in that pit latrine? Probably too many users for one toilet? Soil not enough infiltration capacity to infiltrate liquids? Groundwater table too high? Too much liquid added (get the users to urinate in a separate urinal and soak pit?)

Difficult to say, please give us more context to your question. Actually, now I noticed that you said they are "completely sealed pit latrines". If they are sealed at the bottom then they are not a pit latrine? Pit = infiltration? You mean rather a holding tank? Maybe you should convert it to pour flush in that case?

Oh and welcome to the forum! :)

Regards,
Elisabeth

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  • Angus
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Re: What can I add to a pit latrine to stop it smelling?

Hello Elisabeth,

Thanks for the links: those commercial pit additives aim to (and fail to) increase decomposition of the faecal matter, and are not designed for smell reduction. Maybe something similar to the toilet fluid used for camping toilets might work?

The pit latrines (or 'holding tank latrines'?) are shared communal latrines in a refugee camp. They are fully lined so no liquids can infiltrate the soil. Unfortunately this is a regulatory requirement and can't be changed. Some of the pits are pour flush but apparently they still smell.

Adding lime might work, but would alter the pH and might cause problems for the treatment plant. Could this be mitigated somehow?

To introduce myself, I have been following this forum for quite a while. I am a civil engineer working for Oxfam researching sanitation solutions suitable for emergency situations. I have previously volunteered in South Africa working for Dave Still emptying pit latrines.

Angus
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  • nazir
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Re: What can I add to a pit latrine to stop it smelling?

Dear Angus

Kindly contact me on : This email address is being protected from spambots. You need JavaScript enabled to view it. would be glad to send you samples for trials.
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  • Angus
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Re: What can I add to a pit latrine to stop it smelling?

Hello Nazir,

I have contacted you by email to see if we can arrange a trial with your product.

Angus
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  • nazir
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Re: What can I add to a pit latrine to stop it smelling?

Thank you, as soon as I receive your mail, I will respond to your esteem self.
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  • MRonteltap
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Re: What can I add to a pit latrine to stop it smelling?

And is changing to urine diverting an option for you? Have you followed the work of SOIL in Haiti? They took the existing chemical toilets and converted them into UDDs with great success. Of course you need the proper O&M and all the other difficulties, but surely life is not easy now either - with sealed pits there will be a lot of desludging involved.

Good luck, and indeed keep us posted,
Mariska.
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  • F H Mughal
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Re: What can I add to a pit latrine to stop it smelling?

Odour control can be achieved by using lime (as has been mentioned above). A little elevated pH of the contents would not be a problem in wastewater treatment. In some restricted areas, air-freshener tablets are kept at appropriate places. They act to neutralize the pit odours.

Siting of the pit latrine, relative to wind, is often helpful. Under a draft, odors are removed quickly (natural convection). Keeping the pit area well ventilated is also helpful.

If nothing else works, then the best option would be to put up a vent (this will convert the pit to ventilated pit latrine). The vent acts to suck up the odours into the pit and up to the vent. It should be ensured that the vent protrudes well above, to make it work. Painting the vent black helps to maximize absorption of heat from the sun. Hot air rises in the vent and, in the process, draws air from the pit.

F H Mughal

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  • JeffHoliman
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Re: What can I add to a pit latrine to stop it smelling?

Dear Angus,
From my experience with bucket toilet system, I have found that in addition to urine diversion, which others have recommended here, integrating crushed BIOCHAR (charcoal made by particular process for the purposes of integrating into soil building efforts) with the high carbon cover material such as sawdust, woodchips, leaves, coffee bean hulls is effective to help absorb odors. Adding biochar to dry toilet systems is an excellent way to "charge" the sterile black carbon scaffold which is biochar, with nutrients and microbes, so as to be able to enhance the soil food web upon additon to ecoagricultural systems. This biochar can be produced as byproduct from relatively simple TLUD (top lit updraft) cooking stoves that can utilize agricultural waste in order to cook meals.

Ideally, the pit could be redeigned in order to recover this valuable soil amendment.
Kind regards,
Jeff Holiman
PHLUSH

Jeff Holiman
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Portland, OR, USA
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