Monday, November 12, 2012

For our convenience

We use many names for the place where we perform our daily business. Snobs prefer the old-fashioned ‘lavatory’, and Americans the ‘restroom’ – suggesting a place where one might lie down and doze.
Despite its supposed vulgarity, ‘toilet’ is the word that has entered international parlance and carries the flag in the formal literature. Derived from the French ‘toilette’, it links the concepts of sanitation and grooming. Cultural ideas of cleanliness and personal convenience have driven toilet evolution more powerfully than public health.
Over time, there have been shifts between ‘dry’ and ‘wet’ forms of excreta receptacle and disposal. The system using porcelain bowl, water-seal U-bend and plumbing connection to a sewer only became widespread in the West late in the 19th century. It gradually replaced the earth closet, privy, outhouse and other ‘dry’ systems, and revolutionized defecation by bringing it indoors.
Today’s need for a sanitary revolution, together with the high costs of sewerage and the profligacy of using water for flushing means that ‘dry’ – ecologically more correct, composting toilet models – have made a comeback.
1. First flush – Fit for a Queen
Sir John Harington’s design for the first water closet. In 1592, Sir John installed this in his house near Bath to impress his godmother, Queen Elizabeth I. Harington hoped to make his fortune, and published a book: A New Discourse on a Stale Subject. His boast was to transform your ‘worst privy’ to become ‘as sweet as your best chamber’, but it did not catch on. The water cistern is A, the seat D, the stool pot H; water was released from the cistern to a point just below the seat, and the key G opened the brass sluice K and flushed the waste into the water below.
2. Commercially successful toilet pans
In the late 18th century, patents were taken out by new pioneers, including Joseph Bramah (1778), whose pan with valves was the first to achieve commercial success. The more famous Thomas Crapper (1835-1910) was not technologically inventive, but strikingly successful as a sanitary entrepreneur. Valve WCs became standard fitments by the mid-1800s; but their workings were complex and liable to fouling or breakdown. Worse, the amount of waterborne detritus released into inadequate drains threatened public health: the 19th-century flush toilet actually contributed to epidemics of dangerous disease until proper sewerage came along.
3. ‘Dry conservancy’
Sewerage was not universally approved, given the volumes of excreta polluting the rivers and the squandering of nutrients valuable to farming. So there were many advocates of ‘dry conservancy’. One successful promoter was the Reverend Henry Moule.
a) One of his more fancy toilets, manufactured in 1863. The contents of the fixed pan beneath the seat led into a trough, where they were mixed by a rotating screw and deposited down a chute. The model remained on sale until the 1930s.
b) A later design of 1873 was much simpler: the brass handle was pulled up to draw the hopper forward and release soil into a bucket under the seat hole.
4. The absorbent pail system
In the late 19th century, over 100 large towns and cities launched schemes for the collection of faeces from households and its distribution as fertilizer. But the recycling of human excrement never became profitable.
A toilet pail for systematic delivery and collection, designed by a Frenchman, Pierre Goux. After emptying, it was repacked with three inches of absorbent material at the side and four inches at the base. The pail was used in northern British towns and military camps in the 1870s.
Simplified sewerage with standard pans for sitting or squatting has become more widely deployed in poor urban environments in recent years. But where any form of sewerage is impracticable and too expensive, ‘on-site’ toilets – combining the personal need for a place to ‘go’ and a system of excreta removal or storage – are the only option. Different variations of ‘dry’ and ‘wet’ have been developed in recent years, in a new explosion of toiletary invention. Except where human excreta are valued in agriculture, ‘wet’ is almost always preferred, although, used properly, ‘dry’ need not smell.
1. The double-vault composting toilet
An early modern composting toilet, invented in Vietnam in the 1950s. It is for people who collect excreta for fertilizer in areas with a high water table, where dug pits may lead to pollution. The above-ground compartments for the shit – urine is diverted into a pot – need not be large since faeces alone do not take up much space. This can be seen as the original eco-san toilet: many other smarter versions now exist.
The two compartments are covered by a urine-diverting squatting slab. When one is full, its drop-hole is covered and sealed, and the other used instead. After a year, the composted faeces – now entirely inoffensive and safe – are removed via the door.
2. The ‘ventilated improved pit’ or VIP
The VIP is today’s aristocrat of stand-alone ‘dry’ toilet houses for rural areas in Africa and some other water-short parts of the world (Uzbekistan, China and Afghanistan have taken it up, but not South Asia, where ‘dry’ is culturally less acceptable). It was invented in Zimbabwe and originally known as a Blair (after a former health secretary). The key is the vent-pipe, which sucks smells up courtesy of the wind, and traps flies aiming for the light. There are variations in building materials, affecting costs; and in pit numbers and eco-refinements. The expense of a solidly constructed VIP (over $200) can be a problem.
3. The sanplat
The sanplat is a much more basic affair, and in different variations – some of which incorporate vent-pipes – is today’s brand leader for cheap ‘dry’ toilets in Africa. It consists of a moulded slab, in thin concrete or reinforced plastic, with a drop-hole and fitting plug, fabricated for as little as $2. The plastic version (more expensive) can be carried home on your head. Slab and cover are placed over a pit in a ventilated cubicle or surrounded by a brush fence and left open to the sky.
4. The twin-pit pour flush
This ‘wet’ toilet with a pan and water-seal has been constructed in public blocks to transform daily lavatorial life for millions of Indians in urban slums. For a household, the toilet is expensive ($200 or more, depending on materials) as well as requiring a lot of space. Simpler versions in polished cement (just the pan and slab, a water-seal version of the sanplat) are fabricated in village production centres in parts of India and Bangladesh, and are bought by millions of customers for use over a single pit, for as little as $8.
All illustrations on this page are from David J Eveleigh, Bogs, Baths and Basins: The Story of Domestic Sanitation, Sutton Publishing, 2002.

No comments:

Post a Comment