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Excrement Happens For centuries, society has been faced with a problem: what to do with the vast volumes of human waste produced by its population. Treated properly, human excreta can be a natural and beneficial fertiliser. But today, across the industrialised world, we are paying the price for two centuries of a 'get rid of it ' approach to human wastes - and our soil is being poi­soned as a result. By Peter Montague.

Ho w I t Al l Bega n Humans began to lead a settled life, growing crops to supplement hunting and gathering, only about 10,000 years ago. For all time before that, humans "deposited their excreta - urine and faeces on the ground, here and there, in the manner of all other land creatures."1 The soil and its communities (including plants, small animals and micro-organisms) captured almost all of the nutrients in animal excrement and recycled them into new components for soil. In this way, the nutrients were endlessly recycled within the soil ecosystem and largely kept out of surface water.

As a result, what we call 'pure water' is low in nutrients, particularly the major nutrients nitrogen and phosphorus. Because these conditions have existed for a very long time, life in lakes, rivers and oceans is accustomed to the relative absence of these nutrients. Over the past couple of billion years, life has flourished in this low-nutrient environment, growing complex and interdependent in the process - an aquatic condition we call 'clean' and 'healthy'.

When a body of water is suddenly inundated with nutrients especially nitrogen and phosphorus - things change drastically. One or a few organisms flourish and begin to crowd out the others. We can all recall seeing a body of water that is pea-soup green from overgrowth of algae. Such a water body is clearly sick, choked, its diversity vastly diminished.

Today, much of the surface water of the planet is in a state of il l health because of misplaced nutrients. And a main contributing culprit is misplaced human excreta.

Eas t an d West : Conflictin g View s o n Sewag e Managemen t Long ago, human civilisations split into two camps regarding the management of excreta. Many Asian societies recognised the nutrient value of 'night soil' (as i t became known). For several thousand years, and up until very recently, Asian agriculture flourished by recycling human wastes into croplands.

The opposing camp, particularly in Europe, had ambiguous feelings about human waste - was i t valuable fertiliser or was it a nasty and embarrassing problem to get rid of?

In Europe, a pattern evolved: the first stage was urinating and defecating on the ground near dwellings. As population density increased, this became intolerable and the community pit evolved. For privacy, this evolved into the pit privy or 'outhouse' - a structure for privacy atop a hole in the ground. Despite what many people may think, the pit privy is not environmentally sound - i t deprives the soil of the nutrients in excrement, and by concentrating wastes it promotes pollution of groundwater by those same nutrients.

Before the advent of piped water in the late 18th century, Euro-

Algal blooms in the oceans are often a result of sewage pollution.

pean towns stored excreta in cesspools (lined pits with some drainage of liquids) or in vault privies (tight tanks without any drainage). The 'night soil' was removed by 'scavengers' and was either taken to farms, or dumped into pits in the ground or into rivers. In general, Europeans never developed a clear and consistent perception of the nutrient value of excrement, as Asians had done.

In ancient Rome, the wealthy elite had indoor toilets and running water to remove excrement via sewers. Later, European cities developed crude sewer systems - usually open gutters but sometimes covered trenches along the centre or sides of streets - though

The Ecologist, Vol. 29, No 4, July 1999

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