Grantee Research Project Results
Final Report: Electrochemical removal of contaminants of emerging concern (CECs) using modular water reuse system
EPA Contract Number: 68HERC21C0034Title: Electrochemical removal of contaminants of emerging concern (CECs) using modular water reuse system
Investigators: Huong Le, Thi Xuan
Small Business: Faraday Technology, Inc.
EPA Contact: Richards, April
Phase: I
Project Period: March 1, 2021 through August 31, 2021
Project Amount: $100,000
RFA: Small Business Innovation Research (SBIR) - Phase I (2021) RFA Text | Recipients Lists
Research Category: Small Business Innovation Research (SBIR) , SBIR - Water , SBIR - Clean and Safe Water
Description:
The purpose of the research was to demonstrate the feasibility of a technology using a low-cost, scalable and modular electrochemical cell (FARADAYIC® ElectroReactor) and pulsed-waveform electrochemical process (FARADAYIC® ElectroDestruction) for efficient degradation/destruction of pharmaceutical contaminants, which (1) can be easily implemented as small and/or large scale systems, (2) does not require intensive maintenance, and (3) does not generate any salts, chemicals, or harmful by-products after treatment.
In this Phase I SBIR program, Faraday Technology designed and built a modular FARADAYIC® ElectroReactor for electro-destruction of pharmaceutical compounds. To quickly confirm reactor functionality, we initiated work with Acid Orange 7 (AO7), an easily-analyzed surrogate destruction substrate. Various AO7 experiments were performed to investigate the effect of experimental parameters like anode/cathode gap, applied voltage, and electrolyte flow rate of influent. In addition, multiple electrode materials were tested, including (1) boron doped diamond (BDD) and mixed metal oxide (MMO) anodes; and (2) carbon felt and Ti foam cathodes. Two operating modes, (i) anodic oxidation (AO) utilizing Ti foam cathode and (ii) simultaneous AO combined with cathodic electro-Fenton process utilizing carbon felt cathode, were used. The concentration of AO7 in the influent and effluent flows was identified using UV/Vis assay measurement. The knowledge gained from the Acid Orange 7 destruction tests was transferred to acetaminophen (ACE) experiments.
Faraday performed full factorial experiments for ACE to understand the effect of pulsed-waveform FARADAYIC® ElectroDestruction, number of passes, and influent flow rate on the acetaminophen destruction efficiency. The ACE concentrations were measured by HPLC/MS/MS at the University of Illinois at Chicago (UIC) Research Resources Center. The identity of ACE by-products was qualitatively determined by SVOC-TIC (Semi Volatile Organic Compound - Tentatively Identified Compounds) at a local laboratory (Pace Analytical, Englewood, Ohio). To validate the performance of the modular FARADAYIC® ElectroReactor and FARADAYIC® ElectroDestruction process for destruction of pharmaceutical contaminants in real streams, Faraday carried out experiments for the electro-destruction of ACE in RO retentate and permeate received from the Orange County (CA) Water District (OCWD).
Faraday carried out a technoeconomic analysis of the ElectroReactor/ElectroDestruction technology combination by calculating both an OPEX and a CAPEX metric for the ACE destruction trials. The OPEX metric was a specific energy consumption measure (energy input per log-reduction in ACE per volume of electrolyte) calculated from data including cell voltage, produced current, % ACE destruction and influent flow rate. A CAPEX metric embodying a lumped first-order kinetic representation of reactor performance was developed in order to characterize destruction performance as a function of electroreactor size.
Faraday drafted a preliminary design of an alpha-scale FARADAYIC® ElectroReuse apparatus, to be refined in the Phase II activity. Faraday also performed some preliminary experiments to investigate the performance of FARADAYIC® ElectroDialysis process for elimination of inorganic ions in the electrolyte stream, in anticipation of more extensive Phase II ElectroDialysis development. The ElectroDialysis experiments were carried out for ACE solutions prepared in each of DI water, RO permeate and RO retentate.
For the commercialization activities of the program, Faraday utilized Foresight Science & Technology for their “commercialization readiness report” and “expert and end-user identification” services, and engaged the USEPA and Water Research Foundation as technical and commercialization resources. Faraday reached out to numerous potential commercialization partners, including the Metropolitan Water District of Southern California, the Orange County (CA) Water District, Axine Water Technologies, Ms. Paula Kehoe and Ms. Taylor Nokhoudian of the San Francisco Public Utilities Commission (SFPUC), CONDIAS, numerous U.S. pharmaceutical manufacturing companies, and wastewater treatment plants in Englewood, OH, Toledo, OH, and Charleston, SC.
Summary/Accomplishments (Outputs/Outcomes):
Based on the results obtained from trials for destruction of Acid Orange 7 (AO7), we quickly confirmed the functionality of the modular FARADAYIC® ElectroReactor. The destruction of AO7 increased with an increase in applied voltage, and with a decrease in influent flow rate and in the gap between anode and cathode. The best parameters identified in Phase I for electrochemical destruction of AO7 were an anode/cathode gap of 1 cm, an influent flow rate of 1.8 mL/min, a 4-layer MMO thin mesh anode and a carbon felt cathode; these parameters were used as the baseline for all subsequent acetaminophen (ACE) destruction tests. In these ACE tests, nearly 100% destruction was achieved in a single-pass configuration with initial ACE concentrations lower than 200 ppb. At an initial ACE concentration of 40,000 ppb, the destruction efficiency attained 99.4% after flowing the same solution through the reactor five times, and no toxic by-products were identified in the effluent. On 7/16/2021, a number of samples produced from the full factorial experiments for ACE destruction were sent to the UIC Research Resources Center for LC-MS quantitation; however, the automatic peak-analysis software for the LC-MS system has been malfunctioning for several weeks and delivery of the analytical results has been delayed. These data are omitted from this report, but will be included in the Phase II proposal.
The pulsed FARADAYIC® ElectroDestruction process exhibited favorable technoeconomic performance, with a specific energy input per log-reduction in ACE (OPEX metric) of 2.2 kWh/m3-log at a 6 V peak potential and 25% duty cycle, representing a 90% electricity usage reduction compared to a 6 V DC potential. Significant further reduction in this OPEX metric is likely feasible via further process and FARADAYIC® waveform optimization. The CAPEX metric embodying a lumped first-order kinetic representation of reactor performance suggested that the specific FARADAYIC® ElectroReactor configuration used in Phase I is best suited to remediate streams containing up to ~ 500 ppb of ACE, with an optimal metric of 35 h‑1 observed at an ACE concentration of 200 ppb; further electroreactor design optimization may be useful if streams with higher ACE content are to be processed. Results from Phase II work with other FARADAYIC® ElectroReactor configurations including multiple cells per stack and larger electrode areas will permit the CAPEX analysis based on this metric to be expanded to systems at multiple scales.
Faraday completed a 3D CAD model of the preliminary design of a full FARADAYIC® ElectroReuse apparatus comprising two elements, a FARADAYIC® ElectroDestruction module and a FARADAYIC® ElectroDialysis module. Results from preliminary ElectroDialysis experiments confirmed the feasibility of FARADAYIC® ElectroDialysis to remove inorganic ions in the effluent, producing “fresh” water without any salts, chemicals, or harmful by-products after the treatment. Faraday received the final commercialization report from Foresight Science & Technology Inc., and engaged commercial partners CONDIAS (Itzehoe, Germany), Orange County Water District (OCWD), and Axine Water Technologies (Vancouver, Canada) regarding the Phase I technical approach and Phase II strategy.
Conclusions:
Based on the Phase I data and analysis, Faraday anticipates that pulsed FARADAYIC® ElectroDestruction embodies a revolutionary, novel capability for destruction of CECs in aqueous streams for water reuse systems. The FARADAYIC® ElectroDialysis process, following the FARADAYIC® ElectroDestruction, can efficiently eliminate inorganic ions and enable reuse of the electrolyte streams to produce “fresh” water without any salts, chemicals, or harmful by-products after the treatment. The modular FARADAYIC® ElectroReactor is compact, is significantly more energy- and cost-efficient than the majority of competitor technologies, and can be adapted to a wide variety of water reuse systems in onsite small scales and/or large scale of wastewater treatment plants. Phase II/III efforts will work to establish specific operating parameters for remediation of various CECs in aqueous stream(s) of interest to our commercialization partner(s), as part of progressive larger-scale demonstrations of the technology.
The economic analysis performed as part of this Phase I SBIR program strongly supports the relevance of the modular FARADAYIC® ElectroReactor and FARADAYIC® ElectroDestruction technology for CECs destruction to various applications of commercial interest. The modular design of FARADAYIC® ElectroReactor makes it easily be implemented in small onsite systems to reuse water within individual buildings, at local scale, and/or larger scale systems such as wastewater treatment plants. Both CONDIAS and Axine Water Technologies have expressed significant interest in investigating the performance and economic gains to be obtained from the use of the FARADAYIC® Process with their electrochemical hardware, and Orange County Water District has expressed strong interest in investigating the potential of FARADAYIC® ElectroDestruction/ElectroDialysis to serve as an inline pretreatment technology for their RO concentrate, in order to enable further reuse of that stream instead of discharge to the ocean. The San Francisco Public Utilities Commission (SFPUC)have an interest in technologies enabling remediation of pharmaceutical CECs for building-scale water reuse.
The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.