Sanitation // Green Opportunities for Urban Sanitation Challenges through Energy, Water and Nutrient Recovery
By Pay Drechsel and Munir A. Hanjra. A Nexus approach means that when governments and industries determine policies in one sector – whether energy, agriculture or water – they take into account the implications in other sectors. Applying this approach within an urbanizing world gives the Nexus a vital justification, since nowhere else are the flows of energy, water and food so stressed as where populations peak within confined spaces. Cities are hungry and thirsty and enormous hubs of consumption of all kind of goods, including food, water and energy. This in turn makes them major centres of solid and liquid waste generation. If this waste remains in the urban area or its landfills, cities will also become vast sinks for valuable resources, like crop nutrients, while rural production areas increasingly face soil fertility degradation.