Global Wastewater is a Resource

More people now die as a result of polluted water than die from all forms of war and violence, according to a recent UNEP report.  More than half of the world’s hospital bed occupants are there with illnesses linked to contaminated water.  One child under 5 years old dies every 20 seconds from water-related disease. The global estimate of wastewater quantity from sewage, agricultural and industrial waste is 2000 million tonnes, containing 2 million tonnes of ‘waste’ dry matter.  Couple that with estimates that more than half of the 6800 million global population are now urban, and the importance of municipal and industrial wastewater management becomes obvious.  But some of that ‘waste’ dry matter is nitrogen, phosphorus, potassium and various useful micro-nutrients, plus organic matter from which useful energy could be extracted.  Already about 10% of the world population is supplied with food grown using wastewater fertiliser and irrigation and this could be increased substantially.  The trial in Christchurch growing algae in municipal wastewater for oil production [see Interests and Concerns: Oil from Algae]  illustrates wastewater cleanup alongside bioenergy production.  The Christchurch City Council already uses anaerobic digestion of sewage for biogas production upstream of the wastewater ponds.  The UNEP report lists 6 major recommendations to cope with present and increasing wastewater production, including a ‘source to ocean’ approach and the need for national to local policies and strategies.  That translates in the New Zealand context to a need for national, regional and local policies and strategies.