Recycle those nutrients

Published Tuesday, May 28, 2013 in the New Brunswick Telegraph Journal.

“Dad, I gotta go,” came the little voice from the back seat.  When my sons were younger, it seemed no trip to their grandmother’s was complete without an unscheduled stop for a quick visit to the woods.  I’m guessing it’s a routine familiar to many parents.

As it turns out, peeing in the woods is not such a bad thing – it’s a positive contributor to nature’s perennial flow of nutrients through the various life forms of our ecosystem. 

Nutrient cycling
In Cradle to Cradle, authors William McDonough and Michael Braungart point out that waste is a concept created entirely by humans.  In nature, there is no such thing as waste.  Leaves shed annually by a tree nourish grass.  The grass nourishes animals.  The animals produce manure, which nourishes the tree and helps it produce a new crop of leaves.  It’s the ultimate zero-waste recycling system, as nutrients shed by one life form decompose and find renewed purpose in a new life form.

However, human activities are affecting the flows and balance of nature’s perfect nutrient cycling system.

Fertilizers, sewage and landfills
Our global food production system is dependent on three critical commercial fertilizers, nitrogen, phosphorus and potash (N, P and K).  NPK fertilizers were the force behind the Green Revolution of 50 years ago, underpinning the spectacular increases in crop yields that have enabled us to feed more and more people. That’s been a huge upside. 

But fertilizers have a huge downside too.  Nitrogen is synthesized from natural gas, so it is extremely energy- and emission-intensive.  No natural gas, no nitrogen fertilizer.  Phosphorus and potash are mined from non-renewable deposits around the world.  Potash is plentiful, but long term global phosphorus supplies appear less certain.  Mining, processing, transportation and application of fertilizer all require energy, which usually comes from fossil fuels.

Also, fertilizer is often applied too generously and surplus nutrients leach into rivers, lakes and oceans.  They contribute to aquatic dead zones, where oxygen levels are too low for marine life to survive.  The huge dead zones in Lake Erie and the Gulf of Mexico are graphic examples of what nitrates and phosphates can do to aquatic ecosystems.

Fertilizers are not the sole culprit.  Municipal sewage systems are major sources of nitrates, phosphates and anything we flush down the drain.  It’s comforting to imagine that sewage treatment plants turn waste into pure water, but that only really happens on the International Space Station; you probably wouldn’t want to drink what flows from the outlets of your local sewage treatment plant into the nearest body of water.

Finally, in our squeamish human world, the very organic materials that nature recycles so effectively are often discarded into landfills.  They remain there permanently, the occasional belch of methane being the only reminder of their existence.

What to do
Some of the larger system overhauls needed are beyond the scope of the average consumer.  For example, in agriculture, commercial fertilizer applications need to be better aligned with actual crop needs, and natural materials like manure need to be better conserved and used.  Fortunately, much work is being done in both areas.

Some municipalities are coming to realize that sewage can be a resource rather than a pollutant.  In Oslo, municipal sewage generates biogas to fuel the city’s transit buses.  Some municipalities are also looking at constructed wetlands, where plants extract – for free – many of the waste stream nutrients that would otherwise end up in waterways.

But there is one important thing the average consumer can do: compost.  At home, at work and at school, keep kitchen scraps, coffee grounds and other organic material out of the landfill, and turn it into rich plant fertilizer.  It’s simple to do; the province’s website,, has all the information you need.

And if the opportunity should present itself, don’t hesitate to pee in the woods – because while it’s important to recycle paper and plastic, it’s equally important to recycle nutrients.