Modern Use of Water Produced by Purification of Municipal Wastewater: A Case Study

Giorgia Tomassi, Pietro Romano and Gabriele Di Giacomo
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Giorgia Tomassi: Department of Industrial Engineering, University of Padova, Via Gradenigo 6/a, 35131 Padova, Italy
Pietro Romano: Department of Industrial and Information Engineering and of Economics, Campus of Roio, University of L’Aquila, 67100 L’Aquila, Italy
Gabriele Di Giacomo: Department of Industrial and Information Engineering and of Economics, Campus of Roio, University of L’Aquila, 67100 L’Aquila, Italy

Energies, 2021, vol. 14, issue 22, 1-13

Abstract: All the urban areas of developed countries have hydric distribution grids and sewage systems for collecting municipal wastewater to treatment plants. In this way, the municipal wastewater is purified from human excreta and other minor contaminants while producing excess sludges and purified water. In arid and semi-arid areas of the world, the purified water can be used, before discharging, to enhance the energy efficiency of seawater desalination and solve the problems of marine pollution created by desalination plants. Over the past half-century, seawater desalination has gradually met demand in urbanized, oil-rich, arid areas. At the same time, technological evolution has made it possible to significantly increase the energy efficiency of the plants and reduce the unit cost of the produced water. However, for some years, these trends have flattened out. The purified water passes through the hybridized desalination plant and produces renewable osmotic energy before the final discharge in the sea to restart the descent behaviour. Current technological development of reverse osmosis (RO), pressure retarded osmosis (PRO) and very efficient energy recovery devices (ERDs) allows this. Furthermore, it is reasonable to predict that, in the short-medium term, a new generation of membranes specifically designed for improving the performance of the pressure retarded osmosis will be available. In such circumstances, the presently estimated 13-20% decrease of the specific energy consumption will improve up to more than 30%. With the hybrid plant, the salinity of the final discharged brine is like that of seawater, while the adverse effect of GHG emission will be significantly mitigated.

Keywords: freshwater from the sea; purification of municipal wastewater; osmotic energy; reverse osmosis; pressure retarded osmosis; process integration; energy efficiency; environmental sustainability (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2021
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (2)

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