Yes, you are right Christoph.

Dry latrines are not connected to any sort of pit or septic tank. They have a divider to separate urine and feces. Urine flows out to the nearest drain or evaporates in certain cases. But the feces needs to be scooped up and disposed somewhere.

Very nice pictures and comments.
I really enjoyed. Just one question/remark. I think it is confusing when you speak of dry latrine.
Even I did not understand very well what is meant. I guess a latrine without any from of flushing? Is that right?

Congrats.
Christoph

Thank you all for your inputs. I am sorry for the delay in my reply. I started traveling soon after putting this query up on SuSanA. I will go through your responses and get back to you soon.

Here is the link to the short photo essay on manual scavenging that kept me busy. It might be of interest to some of you - sharadaprasad.com/portfolio/essays/manual-scavengers-of-lucknow

I wonder if we need to take a step back from 'counting pathogens' and look at the 'overall transmissibility and outcome of exposure' to these biological entities.

For a pathogen/parasite to successfully infect a new host through fecal sludge, it must surmount several steps:

1: gain contact

2: retain infectivity - i.e. have enough vitality to establish and procreate once contact is made

3: overcome the potential host's own defences - which are influenced by past exposure, diet, hygiene, genetics and concurrent medical conditions.

I would like to cite helminth control practices used in organic livestock farming here in the UK, which are:
Clean grazing (foraged feedstuffs) for susceptible individuals to reduce burden of exposure;
Optimum nutrition and avoidance of overcrowding;
Strategic use of anthelmintics, vaccines;
Breeding for resistance.

It might be worth considering that humans have evolved alongside a multitude of parasites and pathogens, and encountering some at low levels actually have beneficial impacts on protective gut microbiota and immune responses. In developing nations scenarios, there are usually individuals who appear remarkably healthy in the face of vast health challenges. Too clean can perhaps be damaging as too dirty!

Susannah Batstone, Soilet Systems.
Convinced that tiny things can solve big problems!

+++++++++

Note by moderator:

A reply by Keith Bell in this thread has been moved to here to keep this thread more focussed:

forum.susana.org/forum/categories/92-nut...e-to-poor-sanitation

We also found this references of articles that work with treated and untreated sludges hope they have information usefull to you:

Blanca E. Jiménez C., Catalina Maya R. and Germán Salgado V. (2001).
The Elimination of Helminth Ova, Fecal Coliforms, Salmonella and Protozoan Cyst by Various Physicochemical Processes in Wastewater and Sludge. Water Science and Technology.43 (12): 179-182. **Indexed in the MEDLINE database.


Jiménez, C. Maya, E. Sánchez, A. Romero, L. Lira and J. A. Barrios (2002).
Comparison of the Quantity and Quality of the Microbiological Content of Sludge In Countries with Low and High Content of Pathogens. IWA Journal Water Science and Technology. 46 (10): 17-24


Diaz-Avelar J., Barrios J.A., Maya C. and Jiménez B. (2004)
Reduction of Helminths Ova and Faecal Coliforms in Biological Sludge using a Biodegradable Acid (PAA). Water Environmental Management, 7:299- 306.

Jiménez B., Mendez J., Barrios J., Salgado G. and Sheinbaum C. (2004)
Characterization and Evaluation of Potential Reuse Options for Wastewater Sludge and Combined Sewer Systems in Mexico. Water Science and Technology, 49(10):171-178. ISSN: 0273-1223.

Jiménez B., Barrios J., Mendez J. and Diaz J. (2004)
Sustainable Management of Sludge in Developing Countries. Water Science and Technology, 49(10):251-258. ISSN: 0273-1223.

Best regards,

Cati.

While there might be a theoretical average pathogen burden on populations, which would be then passed on to sanitation systems, I don't see how that would make much sense to measure in on site sanitation systems, where one might be highly polluted as there is a infected person living in the household, while the one next door is free of most pathogens.
Of course there are some opportunistic pathogens that are wide spread in healthy populations, but those are probably not such a huge concern in most cases.

Measuring fecal coliforms only makes sense as a measure of treatment efficiency as they are by themselves (mostly) non pathogenic.

Maybe you could explain what the actual purpose of knowing/measuring those pathogens would be for you?

Hi

We have a little information on raw untreated sludges. Maybe you can use some of it. Here is a table with the information we have.




Hope it is useful, best of luck.

Cati.

Hello all,

I am trying to estimate the concentration of pathogens in untreated (fresh from the septic tank) septage. I could find papers that estimate the pathogen concentration in treated sludge but not in fresh septage. Many papers acknowledge the lack of data related to the biological characteristics of fecal sludge (data related to physical and chemical characteristics are relatively easier to find)

Studies of Heinss et al (1994 and 1998) provide a wide range for Helminth egg concentration in fecal sludge. And multiple studies in African slums list - NWSC (National Water and Sewerage Corporation) (2008). Kampala Sanitation Program (KSP) - Feasibility study for sanitation in Kampala, Uganda - as the source of estimating fecal coliform concentration.

I was wondering if you have come across any other papers that estimate the concentration of any of the following pathogens in untreated septage.

• Protozoan parasites
• Enteric viruses ( Enteroviruses, Rotavirus, Adenovirus, or Norovirus)
• Enteric bacteria (Salmonella or shigella)

Haas et al (2014 2nd ed) lists the concentration of all the above pathogens in human feces. But I am not sure whether we can estimate the concentration in fecal sludge based on the concentration in feces (die-off rates are not easy to assume).

I searched through SuSanA posts and I could not find any information related to concentration of protozoa, viruses or enteric bacteria.

Any pointers are highly appreciated. Thanks.

Best,
Sharada