Toilet Ecologico

P. MORGAN

COMMENT BOOKS & ARTS

An ‘eco’ toilet such as Peter Morgan’s Blair VIP, which traps disease-carrying flies, can transform lives.

E CODESIGN

The bottom line

If architecture is ‘design for living’, one of its greatest
challenges is how to live with the masses of waste we
excrete. Four pioneers in green sanitation design outline
solutions to a dilemma too often shunteddown the pan.

E

very year, on average, each of us excretes
50 litres of faeces, rife with pathogens
and heavy metals. Multiplied by Earth’s
population of 7 billion — and rising — that
constitutes not so much an elephant in the
room as a herd of mammoths. Sustainable
solutions are urgently needed, particularly
for the 2.6 billion people who lack adequate
sanitation and the 1.1 billionpractising open
defecation. Rich countries, meanwhile, often

have hidden sanitation issues of their own.
There is no single design solution to sanitation. But there are universal principles for
systematically and safely detoxifying human
excreta, without contaminating, wasting
or even using water. Ecological sanitation
design — which is focused on sustainability
through reuse and recycling— offers workable solutions that are gaining footholds
around the world, as Nature explores on the

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© 2012 Macmillan Publishers Limited. All rights reserved

following pages through the work of Peter
Morgan in Zimbabwe, Ralf Otterpohl and
his team in Germany, Shunmuga Paramasivan in India, and Ed Harrington and his
colleagues inCalifornia.
In compost-based ecosanitation, excreta is
reframed as a resource: fertilizer. Much of the
research on this has focused on upping nutrient levels and finding faster, more effective
ways of removing heavy metals and pathogens such as viruses. Meanwhile, researchbased, ecological processing of waste water is
vastly improving water-based systems, bringing them closer to the ecosanitationideal.
Environmental sustainability is only part
of ecosanitation, however. Defecation is as
culture-laden as other behaviours, so the
designs must also be socially sustainable
— tailored to local customs and strictures,
whether in Malawi or Manhattan.
The developed world may think it has
cracked the problem, but trouble is gurgling
away underground. ‘Flush and forget’ sanitation systemsconstitute one of the more
bizarre hangovers from the Victorian age. In
older toilets, up to 25 litres of drinking water
go down the pan per flush, although ‘lowflow’ toilet designs are coming into their own
and, in 1995, the US federal government set
a 7-litre-per-flush limit.
Aside from wasted water, the faeces-laden
‘black water’ from flush toilets is not always
treated. Many older USand UK sewage systems, for instance, mix toilet waste water with
storm water in so-called combined sewage
outflows, which can overflow after heavy
rain. The US Environmental Protection
Agency estimated in a 2004 report to Congress that 850 billion gallons of untreated
water were entering US waterways every year.
Sewage sludge — the semi-solid mush left
after wastewater treatment in sewageworks
— can be as problematic. Although it can
contain significant traces of pharmaceuticals
and heavy metals even after treatment, it is
widely used in the West as a soil conditioner
and fertilizer on cropland, with uncertain
effects on human health.
In the packed cities and scattered villages
of the developing world, the challenge is
even more daunting. Thousands of children
die everyday from a lack of basic sanitation
or clean water. Open defecation contaminates soils with the eggs and larvae of soilborne intestinal worms, or helminths, as well
as other pathogens. More than one billion
people are infected with these helminths,
which cause, among other problems, weakness and malnutrition.
So a toilet can be transformative. A clean
environment means better health — and...