Toilet Selection for a Small Clinic in Tanzania
A small UK based charity is supporting a Health Centre in Tanzania with two wards of 20 men and 20 women beds but the health clinic lacks any sanitation. They are also working with a local NGO that is working on improving agricultural activity in the area. They supplied a tractor and trailer so could possible use compost from compost toilets.
The proposal is to have two pit latrines, one for each ward. Can we review and suggest suitable options? They have been quoted at around £1800 for the installation of the toilets.
The Questions relating to this issue are:-
• Are they going for the best option, the basic pit latrine, what alternatives might be considered in their particular circumstances?
• Does the cost sound reasonable?
• What are the implications in terms of sustainability of the sanitation, won’t a pit latrines need to be replaced / dug out at some point in the near future and who will manage the ongoing maintenance?
They lack mobile coverage in the village in which they are working so they are looking to install a small satellite dish powered by solar panels with a modem. It will cost around £1000 to install and around £1000 per year for the service charge. They are currently talking to SimbaNET which looks like they operate in Kenya and Tanzania. The questions he has on this installation are:-
• Do we know if SimbaNET are a good and reliable company that would be ok to work with?
• Does the cost of £1000 installation and £1000 per year service charge seem reasonable?
• Have they missed anything that they should be considering here?
It looks like something for the Kenya office in most respects but especially in relation to SimberNET.
Generally, toilet design should be based around composting solutions. The essential difference between these and latrines is that fecal matter is collected in a containment vessel rather than just allowed to collect in a pit and seep into the water table. Vessels can either be constructed of masonry or based on manufactured tanks or large bins - depending on what is available. This allows residues to be moved away from other WATSAN facilities and also for aerobic treatment before they are disposed of.
Composted waste (humanure) is a useful resource if well made and can help to recycle nutrients back into soil fertility. However, if the waste is coming from a health clinic you must be aware that there may be virus contamination of the waste. In a well designed latrine this will not be an issue as the viruses will have died before the pit is opened for emptying - assuming that the filled latrine pit is sealed for about 18 months to 2 years before final emptying. If that is how the system is designed you will of course need a second pit to be used whilst the first is sealed. You must also consider ensuring that no other medical waste is disposed of in the latrines, especially sharps which can be a major hazard if the waste is to be composted.
In terms of cost, I don't have any experience of costing in Tanzania so can't really comment.
The health facility will need to designate staff to maintain the latrines in a clean and safe condition and this should be established immediately. Again, I'd reiterate the need to educate staff on the need to ensure not medical waste is disposed of in the latrines.
On the question of latrines, this is not my specialist field, but I have lived and worked here in East & Southern Africa for many years and I can tell you what I have observed in passing, as follows:
- Yes, Ventilated Improved Pit (VIP) Latrines would be the best solution. One sees these in use at schools and clinics throughout the rural areas of the region.
- From recent personal experience in Zimbabwe you could cost these at $250-$300 per unit, provided you adopt a cost-effective design and get the community to provide all the locally available materials (such as river sand) free. Therefore, with your £1800 you should easily be able to build more than one unit per ward (and I think you will need more than one).
- There is a wealth of information and advice available on the Internet, including an old, but excellent, World Bank report that will tell you all you need to know about the design and construction of VIP latrines: see https://www.pseau.org/outils/ouvrages/....
- The first step is to decide on the preferred life of the units. Obviously the longer, the better. But the longer the life, the higher the cost. My suggestion would be to start by assuming a required life of, say, 10 years and to see how this translates to the number of standard units required vs the budget. Consider life vs the cost of emptying (but I must say I have never seen VIP latrines being emptied anywhere).
- The World Bank report tells you how to calculate the annual volume of deposit per person and how to translate this into the number of standard units required for the life required and number of people to be served.
- Points to note:
- Make sure that the interior of the cubicle is permanently dark. Do not include a door (they get left open; hinges get broken). Instead use a helical superstructure (see WB report -- unfortunately the figures in the copy I referred to are indistinct, but I am sure there are better copies available; if not, let us know).
- Don't worry about a pedestal: a hole in the cover slab is fine.
- Do NOT exclude the flue. This can be a built-in pipe or a flue built in masonry/brickwork, but in either case do NOT exclude the fly screen.
- Do NOT leave a gap between the walls and roof (or windows/wall vents/any other source of interior light).
Suggest thinking carefully about two toilets per ward (so one always available while other being cleaned / repaired) also to making sure all surfaces including lower section of walls can be cleaned easily - note enormous challenges in UK hospitals around hygiene. Some patients will have possibly highly infectious diseases... There are lots of useful references on line. Googling "pit latrine hospital ward" for instance throws up documents by both UNICEF and WHO. I am sure others will be available from IRC, WEDC, MSF etc. Finally the question does not mention whether water is available. If it is, then other solutions might be better. I would suggest focusing on hygienic latrines which are used well (big enough challenge) before exploring whether composting for agricultural (health risks and cultural practicse!!!) use is also an option.
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