50 ways to clean your waste

On a 2003 assignment, I first saw and used the traditional Ladakhi composting toilet. Without a hint of disgust, the farmer described how he extracted the fertilizer from the composting chamber. He changed the way my urban eyes saw sanitation, farming and nutrient cycles; it was an 'outsider coming in' experience. The unlearning and learning that followed resulted in my 2016 book, Jal Thal Mal, on the subject. The Other Dark Matter, however, is an 'inside-out' book, written by a farmer's grandchild.

Lina Zeldovich grew up on a Russian farm, watching her grandfather composting human waste into fertilizer. In that, her book should stand with the likes of Joseph Jenkins' masterpiece The Humanure Handbook and Gene Logsdon's charming 2010 book Holy Shit; both are books on sanitation by farmers. But Zeldovich begins where the two farmers (and her grandfather) left. Because she moved from Russia to New York City, became a widely published science journalist, travelled the world, examined a variety of innovations in sanitation, assessed the technology options and has pushed the envelope. Her farm-derived sensitivity extends into a common-sense humanity - the oft-forgotten 'sanity' in sanitation - that she puts to work across global horizons.

When the material is complex, communication requires simplicity. The book is broken into three chronological sections: the first describes the past in five chapters; the second section is the heart of the book, examining 'the sludge revolution in progress'; and the third looks at the future, detailing the cutting edge of possibilities. For the lay reader, there is emotional connection with the characters and their tribulations. But even readers familiar with the history and ecology of waste management will not be disappointed.