Given that water is an extremely scarce resource, encouraging wastewater management and improving the water quality are extremely important aspects of any eco-city.  According to a  United Nations report, water demand is growing at twice the rate of population growth. The report also states that about 80% of wastewater from human settlements and industrial sources is discharged into the environment without treatment. Urban areas have large areas of impervious surfaces that increase the risk of surface run-off, leading to frequent floods, especially during monsoons. Further, such surfaces also reduce groundwater water recharge. Urban areas also have a large demand for food and thus depend on agriculture, which is a water-intensive activity.

Along with wastewater, urban areas also generate large quantities of solid waste that also poses serious challenges for city planners. A report by the World Bank estimates that cities currently generate roughly 1.3 billion tons of solid waste per year. These are projected to grow to 2.2 billion tons per year by 2025 – an increase of 70 percent. Inefficient disposal of solid waste can lead to serious health issues in cities. It is thus clear that without strategies for effective solid waste management;  recycling and efficient use of water; the growth of cities will be constrained.

However, both wastewater and solid waste issues also present a large opportunity for cities to lower their carbon footprint. Since water and waste management is inextricably linked with energy, it can present opportunities for sustainable energy generation. Further, techniques such as water harvest, greywater recycling, etc. can meet irrigation demands without putting pressure on scarce water resources. Further, as has been shown in the figure above, waste and wastewater management can have significant returns on investments primarily by avoiding health-related costs. It is thus important to implement effective strategies for waste and wastewater management. In the section below we recommend the five most important strategies.