Well-- In Yemen, in Shibam, they employ a dual sewage system. Simply put, liquid waste is piped away while solid waste collects at the bottom of dropshafts until it’s removed and spread on the fields.
I’m in a planning class, though I’m concentrating on a project more to do with trash removal. Another person in the class is doing the sewage system. She contends that this is a viable method, that Americans are just too squeamish about our waste products.
I contend that it’s a health hazard. Even though it’s a desert climate and the matter dries out, and the smell is minimal…
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This is according to our prof, who oddly enough has a UN grant to try to develop plans for this city…and has given the the assignment to us to write the proposals …
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I think that the fecal material will still contain spores from bacteria that pass through the digestive system, and that these spores could be inhaled and cause disease through that vector.
Anybody know about this?
Well, just off the top of my head, people have been doing it this way for thousands of years. The trick is to have a low enough volume of sewage that Mother Nature takes care of it, via flies, sunshine, microbes, etc., so the level of disease microorganisms doesn’t build up quite so high. It works OK for widely scattered towns with access to rural land (or open desert) for dumping the “honey buckets”, but it wouldn’t work for, say, Chicago, where’s just too much “solid waste” and nowhere to put it.
Also, Yemen is about half desert, and I would think that the hot sun and drying winds would have a certain disinfecting effect.
That said, I personally don’t think it sounds very sanitary, but we can hardly expect the Third World to install flush toilets and modern sewage disposal systems before they even have decent supplies of running water. The CIA Factbook says, about Yemen:
They have a per capita income of $820 a year, with a GDP of $14.4 billion, and the CIA says they’re “one of the poorest countries in the Arab world”. Sewage disposal plants cost money, and call for a lot of infrastructure (pipes and water mains and things), which also cost money to install and maintain. Look at some of these prices for sewage disposal projects. We’re talking $780,000 just for a sludge tank.
Take London as an example: until the flushing toilet was invented, all waste went into a night soil pit, which was collected at night. When the flushing toilet was invented, everything went down a sewer into the thames. As a consequence, the Thames smelled pretty horrible most of the time, and caused many outbreaks of cholera, etc. Fortunately for us, the Government did something about this pretty quickly, mainly because parliament was situated just on the bank of the Thames, and the MP’s couldn’t stand the smell. At this point Bazalgette stepped in, and built the sewage system, half of which is still in use, and this helped the disease problem.
This seems to suggest that there’s not a problem with the dropshaft process you mention.