Four Elements

Coastal megacities in emerging economies such as India and Bangladesh currently face severe environmental deterioration due to rapid population growth coupled with increased waste, wastewater and sewage sludge generation. At the same time, fresh water sources are overextended as a result of excessive withdrawals, climate change related salinity intrusion and weakened soil structure. These problems result from overburden on entrenched systems of waste management and food production, and the pressures on built, natural and especially boundary environments will only increase in the coming years. Thus innovative approaches are required which make use of existing and novel synergies within the food-water-energy nexus, and tackle multiple problems simultaneously while taking into account externalities which might limit project practicability.

Seawater is a practically limitless resource, supplemented by brackish ground and surface water (1%-50% salt content of seawater). There are clear opportunities for next generation synergies between ecological interfaces e.g. soil/water or biomass/atmosphere which exploit natural mechanisms for energy and nutrient transfer along and between trophic levels, and strive toward zero waste. The most promising of these synergies involves the restoration of salt-degraded lands, a goal with multiple cascading effects including community building.

The project will create a comprehensive methodology for food, water and energy production, as well as improved waste management within vulnerable areas in developing countries like Bangladesh and India. To date, no literature is available regarding the combined concept, but several process couplings have been successfully demonstrated previously. The system will combine pyrolysis of organic wastes and bioenergy crops with desalination of brackish/salt water to provide clean water, energy, carbon sequestration and soil amendment in the form of biochar and numerous ancillary benefits which are perhaps harder to valorize but no less vital to ensure a sustainable approach. In addition, halophyte cultivation will be combined with soil phytoremediation in a connected system which filters out salts while providing biomass for pyrolysis as well as freshwater collected from transpiring plants in a solar still/greenhouse assembly.