Complete sustainability in electrodialysis reversal desalination: reusing tertiary-treated municipal wastewater as feed in the concentrate stream and electrodes rinsing water

abstract

Electrodialysis reversal (EDR) has been innovative based on unplanned indirect potable water reuse to replace the same amount of raw water withdrawn from brackish (sea) water source and conserving 15–20% of freshwater by reusing tertiary-treated municipal wastewater (TTMWW) as feed in the concentrate and electrode stream while brackish groundwater (sea water) remains feed into dilute stream. By substituting TTMWW, our analysis shows the resulting total dissolved solid (TDS) concentration in the waste stream lower than that in the original source of brackish groundwater (sea water) which fed into dilute stream. The waste from EDR system with TTMWW as feed in concentrate and electrode streams can be recharged back into groundwater (sea water) source which do not add the TDS concentration. In fact, it reduces the TDS concentration by dilution. New significant findings are: (1) 17,500 m³/d of freshwater could be saved with the data from 1990; the saving would be increased in 2011 and much more in future due to the increasing installation of ED/EDR and (2) cost reductions by enhancing the life of membrane and electrodes; and by reducing current required to attract ions and antiscalant due to low concentration of TDS and low scale causing ions in the TTMWW which fed into concentrate stream.

Keywords:

• EDR
• Electrode rinsing water
• Feed in concentrate
• Fouling
• Scaling
• Unplanned indirect potable water reuse

Acknowledgment

This project was supported by the United States Office of Naval Research (ONR) (Contract # N00014-08-1-0304) and Tier I: Reclamation Cooperative Agreement Program (Bureau of Reclamation GR0002841-GHASSEMI BOR COOP). We also thank anonymous reviewers, editor from DWT for their constructive professional comments, and advices.