1) How did the idea for a book on the treatment of waste come to you?
Somewhat circuitously. I was working at COLORS magazine and our editor-in-chief decided we should do a coffee table book called ‘Cacas’, glossy pictures of excreta and short articles about sewage, shit, waste and toilets. I found it fascinating, a great topic for a book. I also wanted to answer a simple question, which has a very complicated answer: what do we do with our waste and why do we call it waste when it isn't?
2) What was the most surprising thing you learned?
That two thirds of the world's population don't have a toilet.
3) And the funniest?
The “no loo no ‘I do’ “ campaigns in India and elsewhere are pretty funny but also smart. They make having a toilet a social necessity, so brides will refuse to marry grooms who don't have a toilet.
4) Why has human waste disposal become such a problem?
Population growth mainly but it was always a problem. Samuel Pepys once went into his cellar and put his foot into a pile of his neighbour's ‘turds’, as he put it. We used to be far more intimate with our defecatory functions, which was good in that it was frankly discussed, unlike now. But as soon as people moved into the intimate, overcrowded city environments, the safe disposal of shit became more difficult.
5) How deep are we in it?
Very. And that includes our great cities. Anywhere with massive populations is going to have huge issues dealing with waste.
6) Is it a matter of development?
Development is not necessarily the answer. Although waterborne sewerage worked well when there were no population pressures, it has become wasteful, expensive and not particularly sustainable. It’s still the most efficient way to carry away a potentially toxic substance - human faeces can carry 50 communicable diseases along with viruses, worms and bad bacteria - but environmentally, it's questionable.
7) What are the most obvious solutions?
There are plenty, from eco-sanitation (i.e. composting toilets, dry toilets), to reducing the volume of water going into overtaxed sewer systems, to community toilets in slum areas. We need universal sanitation to reduce the appalling number of children under 5 who die of diarrhoea: it's the second biggest killer of children after respiratory disease but still gets a fraction of the funding and the attention. There's now an official UN World Toilet Day, which is a milestone but it needs senior politicians and donors to take it as seriously as they take clean water supply.
8) Is there an upside to waste?
It's not waste. It's a great resource, whether as fertiliser - China has used human waste for 4,000 years - or biogas. Rwanda's prison system makes its own cooking gas and saves 1.5 million USD a year. It can also save your life. If someone has a chronic case of clostridium difficile, a faecal transplant can regenerate healthy bacteria.
9) You’ve just written a book about shipping called ‘Ninety Percent of Everything’. Why the change of topic?
‘The Big Necessity’ was very successful and I spent a year or two lecturing and talking about sanitation. But I love writing books so I had to find a topic that would be as stimulating as shit. I took a trip in a container ship across the Atlantic in midwinter in 1999 and I thought, that's what I want to write about next, an invisible industry that’s fundamental to our existence, just like sanitation. Also, I wanted to go back to sea.
10) If you met your 10 year-old self and you told her she’d grow up to write a book about shit, what would she say?
I think she'd laugh. In a good way.
