Treatment of faecal sludge and disposal at household/local level
We are dealing with an extensive area which has been flooded, meaning that most of the local pit latrines have also been filled with water. The response plan is to empty them, treat and then dispose of the watery faeces locally, as there are no centralised options - this would ideally be at a household or very local level (they normally compost the faeces and use them on fields locally). An option currently being considered is lime dosing for quick treatment, but given that there will be a significant amount of watery sludge, I am expecting the values of hydrated lime needed to be quite high.
I would be interested to hear of any other treatment options which could be considered and have been used before.
Lime is really only for small quantities.
The pits have already flooded, so the environment has lots of faeces spread around. Spread it on the fields as it is, but do not grow salad or other crops that do not need cooking. Educate farmers about the need to wash the produce and wash their hands after working in the fields. The ground is contaminated anyway so this would have to happen whatever you do with the sludge. An improvement would be to bury it or plough it in.
But - do the latrines need to be emptied? check to see if the water is receding. Are the pits full of faeces or silt? Would it be more sustainable to cap these latrines and build some that are more resilient?
Is this flooding frequent?
In addition to Brian's response, I would say that the treatment of sludge in situ is usually very hard, especially if it is quite wet. Pit additives have been shown to have little effectiveness (see this doc), and composting happens only with quite dry content. So I'd say either leave in situ and limit contamination (burying / taking farther away from water sources), or pumping and putting into a drying bed (often one the cheapest treatment options), depending on climate, transport, etc.
Good luck and please give more details of location / possibilities if you need more details.
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