THWRC Awarded Proposal 513UHH0033H

Project number:          513UHH0033H

Title:                             Enhanced Removal Of Viruses And Pharmaceuticals And Personal Care

                                      Products By A Hybrid Electroflotation-Microfiltration Process                       

Lead PI:                        Shankar Chellam

Awarded amount:       $40,000


Project Abstract

We propose to develop and mechanistically understand a novel electrochemical–microfiltration process designed to control micropollutants and viruses with minimal membrane fouling. The electrochemical process will achieve destabilization by the in situ electrolytic addition of coagulants via dissolution of a sacrificial elemental aluminum anode. Electrolysis presents significant advantages over conventional alum coagulation, in part because the applied electric field also generates reactive oxygen and chlorine species, which can inactivate viruses and oxidize trace organics. Further, cathodic release of H2 bubbles concurrently facilitates floc flotation, which will reduce mass loading onto any solid-liquid separation process (i.e. microfiltration membrane) downstream of the electrochemical cell thereby reducing fouling.

The overarching goal of this project is to quantify performance improvements associated with a novel electrochemical–microfiltration system as a multi-barrier process against colloids, trace pharmaceutical and personal care products (PPCPs), viruses, and natural organic matter. The removal/inactivation of three dissimilar viruses and sorption/oxidation of several PPCPs during electroflotation will be systematically enumerated. The proposed research is driven by the hypothesis that electrochemical aluminum addition will effectively inactivate and destabilize viruses and oxidize/adsorb PPCPs. Simultaneously, electroflotation will reduce downstream membrane fouling by decreasing the solids concentration in the feed water. Specific project objectives related to the hybrid aluminum electroflotation-microfiltration process include:

  1. Delineate chlorine and reactive oxygen species generation (·OH, O3, H2O2, 1O2, O2-, HOCl) and electrolysis conditions under which virus inactivation and PPCP oxidation is maximized,
  2. Optimize electrochemical cell parameters to maximize bubble formation and associated electroflotation thereby minimizing mass loading to the microfilter and associated fouling,
  3. Empirically demonstrate enhanced removal of viruses and PPCPs from surface waters,
  4. Systematically elucidate underlying destabilization/removal mechanisms, and
  5. Rigorously quantify the relative effects of physical removal by coagulation and chemical oxidation/inactivation by generation of chemical oxidants of viruses and dissolved micropollutants. Note that cumulative reductions in concentrations during treatment are the result of these two physicochemical processes (i.e. removal and oxidation).

Understanding the interactions of applied electric fields and in situ added electrocoagulants with microorganisms and trace organic compounds is important to develop novel, feasible, improved, and sustainable water purification technologies. To our knowledge, this would be the first rigorous and systematic investigation of contaminant control by such an integrated electroflotation – microfiltration treatment train. Aluminum will be generated in situ by electrolytic oxidation of an elemental anode, which will be accompanied by the cathodic release of hydrogen bubbles due to water splitting. This phenomenon will be exploited to induce floc-flotation and reduce mass loading to the membrane, thereby improving microfilter performance. Lake Houston will be used as a representative surface water source since we are interested in developing alternative treatment processes to meet the increasing demands associated with population growth and mandates to eliminate groundwater usage in the greater Houston area (see attached support letter from the City of Houston). At the successful conclusion of this project, we would have developed a hybrid system that constitutes multiple barriers against current and emerging contaminants. Closely working with City personnel would provide students with an appreciation of more practical aspects of their research.