Chapter 20 - Challenges and strategies of water supply and wastewater management in coastal urban and semi-urban areas

Abstract

Some of the world's greatest cities are harbors. The water supply and wastewater management complexity are compounded by the inland pipeline network design, wastewater treatment bacterial consortium design, and sludge management strategies. The risk of irreversible ecological damage at the point of effluent discharge, either in the marine environment or inland soft water reservoirs and finally, maritime contaminants in sewage backflow creates a unique technological roadblock to sustainability. Against the backdrop of some the significant coastal sectors like San Francisco, Boston, and other African and Indian coastal cities, this chapter focuses on a critical case-study analysis of how the water supply and wastewater management system in the coastal urban and semi-urban areas evolved over the years, addressing the pressing technological challenges and demands of the advancing legal regulations. Predominantly, the current progress of membrane technologies is discussed in this context, and its potential efficacy in water resource management of coastal cities is investigated. To increase the process efficiency of membrane distillation, membrane surface modification is being globally tested by making a hydrophobic membrane superhydrophobic. The success of this approach has been exhibited on many occasions, but most prominently in an experiment using tannic acid and vinyltrimethoxysilane on a PVDF membrane, where the membrane flux increased by almost 41% and process time reduced by around 16.3%. Maritime activities arising from trade-based activities in major coastal cities and other anthropological sources of pollution have caused severe disruption to the marine ecological balance, as evident from the rising of ocean surface temperature anomaly by almost 0.5°C over the last 30 years. A concept model has been designed and presented which aims to make use of the contaminants and pollutants to create an alternate route of energy production, which may be able to meet the ever-rising global need for clean and green energy.