Reprinted by kind permission of Earthworks Magazine
The philosophy of zero waste goes far deeper than simple recycling and seeks fundamentally to restructure the production and distribution systems of our economies in order to prevent waste from being manufactured in the first place.
Different types of waste streams emanate from the urban environment. Organic wastes end up festering anaerobically in the nearest landfill site, belching methane into the atmosphere and contributing to climate change. Inorganic wastes such as plastic, glass and building rubble pile up at landfill sites, and industrial wastes from some of the goods we consume leach their toxic payload into our soils, contaminating the land and our water systems. Sewerage waste is pumped and treated using energy- and chemically-intensive processes which, when they fail, spew sewerage into our rivers and oceans.
With the greater proportion of the world’s human population now living in cities, high-density human habitats generate a particular set of challenges around the management of waste due to the disproportionately large volume of waste generated relative to the geographical space that they occupy. The poor and marginalised of urban society often bear the brunt of this, yet contribute the least in terms of waste output.
According to the Institute for Zero Waste in Africa (IZWA), the adoption of the zero waste philosophy could address many of these challenges, through its focus on the restructuring of production and distribution systems, to prevent waste from being manufactured in the first place. Muna Lakhani, National Co-ordinator and founder of IZWA provides the internationally peer-reviewed definition of the term Zero Waste as being “an ethical, economical, efficient and visionary goal that guides people to emulate sustainable natural cycles in which all discarded materials become resources for others.” At its most radical, the philosophy regards external recycling and landfill diversion as last resorts, since these practices imply a failure.
Lakhani cites the example of sanitation and food production, in which sewerage is fed into a bio-digester where it is anaerobically treated and partially cleansed, producing methane gas as a by-product which can then be burned for energy. The nutrient-rich effluent feeds into an algae pond with additional inputs from the sun via the process of photosynthesis. The algae can be used for animal feed, as fertiliser or as a feedstock for additional bioenergy production. Effluent from the algae pond then enters an aquaculture pond and can be used for floating vegetable production and fish farming. The fish introduce into the cycle some ammonia, which serves as a source of nitrogen for additional vegetable production. After having passed through both an aerobic and anaerobic phases of treatment, the water can also be recycled.
Whilst cities are the major culprits with regards to waste production, they also present opportunities for the implementation of the zero waste philosophy – due to their concentrated spatial layout which allows for more efficient configuration of the water, waste, nutrient and energy flows. A zero waste economy also speaks to some of the current impetus behind job creation in the clean technology sector.
The full article appeared in the August-September 2012 issue of Earthworks Magazine Earthworksmagazine