Solving the problem of waste

There’s no doubt that if the planet is to survive, we have to start doing things differently. That means learning to think differently. One of the mindset changes we need to work on, it seems to me, is our whole attitude to waste and particularly human waste.

These thoughts were prompted by a reading of Al Gore’s interactive book, Our Choice, reissued as an interactive app for Apple iPads, iPhones and iPods earlier this year. You can download the Our Choice app right now.

It’s certainly a thought-provoking read and presents some pretty stark choices. One statement caught my eye: “Modern agriculture is one of the largest sources of global warming pollution.” This is quite some statement because, if it’s true, it really condemns us to extinction. The world population is growing at a rate of about 1.3% a year, which means it doubles in 54 years.

Added to that, a greater proportion of that growing population is emerging into the middle class. Think of the Asian economies (China in particular), Eastern Europe and Latin America. More people eating more food. It’s not only quantity: affluent people want food from all around the world, and more meat, which is very wasteful to produce. In fact, the Food and Agriculture Organisation of the United Nations estimated that the meat industry contributes 18% of all greenhouse gases.

Gore estimates that industrial agriculture uses 10 calories of energy from fossil fuels to produce one calorie of food. This is wasteful enough, you might think, but even more wasteful when you consider that a lot of that food is fed to meat animals, thus further reducing the yield.

In response to the growing world population, agricultural productivity has also increased. For example, US farm output has risen annually by 1.58% per year for the last 50 years, so that 2008’s output was 158% higher than that of 1948. A major factor in this rise in productivity has been the increasing use of nitrogen-based fertilisers. These fertilisers are largely synthetic and to make them requires the burning of enough natural gas to release 1.25 tons of carbon (or 4.6 tonnes of carbon dioxide) into the atmosphere.

Another unwanted by-product of nitrogen-based fertilisers is that they drain into rivers and dams and stimulate the growth of algae in them, and in the ocean. When alive, these algae tend to block out the sun thus affecting the growth of other water-borne organisms; when they die, their decomposition consumes the oxygen dissolved in the water. Fish and other plants die, creating what scientists call “dead zones”.

I’m reminded of nothing so much as an athlete who takes steroids. The results are quite excellent but the muscles (and the body in general) are degraded in ways that are not obvious at the time, but are cumulatively very damaging.

This is a serious problem and clearly it’s only getting worse. However, there is at least a partial solution. Even better, it also offers a partial solution to one of other seemingly intractable problems we just don’t like to face, namely the treatment of human waste.

Current methods of treating sewage are actually as wasteful as the modern methods used to create the food in the first place. Here in South Africa, a water-scarce country, we are particularly sensitive to the fact that treating sewage uses up a lot of water that was costly to obtain and purify in the first place. Haven’t we just signed another agreement to harvest more of Lesotho’s water at vast cost, for example?

In addition, overloaded sewage plants are simply discharging raw sewage into our riverine systems.

A very workable solution for developments such as housing estates (especially golf courses), shopping centres, intensive farming, rural hotels, game lodges, remote clinics, schools and others, is simply to divert all the waste water and sewage into a closed purification system that uses natural bacteria and ozone to purify the water. Once the system is purchased, it is relatively maintenance-free, requires minimal human intervention (no horrible solids to clear!) and produces water that is ideal for irrigating crops or gardens. Clients who use it for that purpose rave about the results. This way of thinking not only saves water, as you can see, it minimises the need for polluting fertilisers.

There’s also a nice symmetry about the whole process.