Ryan Thacher
Ryan Thacher, Ph.D., P.E.
Managing Engineer
Environmental & Earth Sciences
Orange County

Dr. Thacher is an environmental engineer by training, and has over 8 years of experience in the fields of water quality and water resource engineering. Dr. Thacher is working on a variety of projects involving hydrodynamics, the environmental fate and transport of chemical constituents, water resource management, and water quality regulation and compliance. He is involved in California water supply and drought issues, with a developing expertise in California’s Bay-Delta estuary and the Delta Simulation Model. He has helped design and implements modeling studies to site and design diffusers, and to evaluate the impact of industrial discharge and treated wastewater on receiving waters. Dr. Thacher’s capabilities extend to stormwater issues and related construction site best-management practices, including runoff evaluation and design for natural and graded lands. Additionally, Dr. Thacher has been involved in multiple contaminated sites projects in various capacities, including chemical fate and transport investigations, using methods of environmental forensics to determine source contributions, and conducting remediation cost estimates.

Dr. Thacher’s graduate research involved inorganic contaminant transport through environmental media, water chemistry and redox processes, and environmental microbiology. He studied the transport of toxic metals including chromium, uranium, and arsenic through saturated media using electrokinetic phenomena, and remediation using various chemical and biological methods. Remediation was achieved using reduced iron species including zero-valent iron nanoparticles, and iron oxide coated sand. Separately, Dr. Thacher designed, fabricated, and operated microbial fuel cells as an ex situ groundwater treatment approach, and evaluated the feasibility of integration with electrokinetic transport systems. This research included a comprehensive analysis of the effects of natural organic matter on the efficacy of reduced iron species as a remediation tool, and the benefits of natural organic matter serving a multi-functional role as an electron shuttle and a terminal electron acceptor in microbial fuel cells. During a research position with the Space and Naval Warfare System Command System Center Pacific he worked in a small team designing, fabricating, and testing field-scale benthic microbial fuel cells intended to power submersible electronics.

CREDENTIALS & PROFESSIONAL HONORS

  • Ph.D., Environmental Engineering, University of Southern California, 2013
  • M.S., Environmental Engineering, University of Southern California, 2009
  • B.S., Chemical Engineering, University of California, Santa Barbara, 2007
  • USC Viterbi Undergraduate Mentoring Research Award, 2013

    USC Sonny Astani School of Civil and Environmental Engineering Best Teaching-Assistant Award, 2011

LICENSES & CERTIFICATIONS

Licensed Professional Engineer, California, #87757

Publications

Thacher R, Ravindran V, Pirbazari M. Modeling and performance prediction of chromate reduction by iron oxide coated sand in adsorber reactors. AIChE J 2016; 62: 3717–3729. doi:10.1002/aic.15257

Thacher R, Hsu S, Ravindran V, Nealson K, Pirbazari M. Modeling the transport and bioreduction of hexavalent chromium in aquifers: Influence of natural organic matter. Chemical Engineering Science 2015; in press.

Hsu L, Chadwick B, Kagan J, Thacher R, Wotawa-Bergen A, Richter K. Scale up considerations for sediment microbial fuel cells. RSC Advances 2013, in press. Epub ahead of print: http://pubs.rsc.org/en/content/articlelanding/2013/RA/C3RA43180K.

Posters and Presentations

Hsu L, Thacher R, Wotawa-Bergen A, Kagan J, Bell R, Arias-Thode M. Analysis of solid and fiber brush graphite and carbon cloth as cathode materials for benthic microbial fuel cells. Association for Environmental Health and Sciences Foundation, 24th Annual International Conference on Soil, Water, Energy, and Air, Abstract reference No. 0192-000167, San Diego, CA, March, 2013.

Thacher R, Pirbazari M. Hexavalent chromium remediation by electrokinetic transport and zero-valent iron nanoparticle injection: Effects of organic and inorganic groundwater constituents. Presented at the AIChE Annual Meeting, Pittsburg, PA, October 28–November 2, 2012.

Thacher R, Hsu L, Pirbazari M. Integrated electrokinetic and microbial fuel cell technologies for enhanced transport and bioremediation of hexavalent chromium in groundwater. Presented at the AIChE Annual Meeting, Pittsburg, PA, October 28–November 2, 2012.

Gray H, Thacher R, Ravindran V, Pirbazari M. Removal of radioactive uranium from groundwater using nanoparticle technology and bioremediation strategies. AIChE Annual Meeting, Pittsburg, PA, October 28–November 2, 2012.

Thacher R, Pirbazari M. Evaluating the dynamics of an integrated electrokinetic and zero-valent iron nanoparticle system for treatment of hexavalent chromium in groundwater. Presented at the AIChE Annual Meeting, Minneapolis, MN, October 16–21, 2011.

Thacher R, Chan C, Hsu L, Pirbazari M. Transport and remediation of chromium (VI) in groundwater using an integrated electrokinetic and nanoscale particle technology. Presented at the AIChE Annual Meeting, Minneapolis, MN, October 16–21, 2011.

Hsu L, Thacher R, Yokota-Joshi A, Wong A, Nealson KH, Pirbazari M. Evaluation of a novel bioremediation process coupling an electrokinetic system with microbial fuel cell technology. AIChE Annual Meeting, Salt Lake City, UT, November 7–12, 2010.

Prior Experience

Graduate Research Assistant, University of Southern California, 2010–2013

Naval Research Enterprise Internship Program, Space and Naval Warfare System Command (SPAWAR) System Center Pacific, Summer 2012

Water Resource Engineer Intern, Los Angeles Regional Water Quality Control Board, 2009–2010

Professional Affiliations

American Institute of Chemical Engineers—AIChE (member, 2005–2015)

American Water Resources Association—AWRA (member, 2013–2015)

Project Experience

Provided technical support for multiple municipalities in the hearings regarding the petition filed by the California Department of Water Resources and U.S. Bureau of Reclamation requesting changes in water rights for the California WaterFix Project. Investigated the effects of proposed project operations on water quality throughout the Sacramento-San Joaquin River Delta (Delta) using the DSM2 model. Evaluated the impact of predicted water quality changes on drinking water diversions, treatment operations, and costs.

Supported an investigation of the formation of a small delta in the Colorado River allegedly caused by land grading activities. Calculated stormwater runoff and sediment transport quantities from the watershed and from graded land and determined that grading had a less than significant influence on delta development.

Estimated soil excavation costs for a diesel spill resulting from a tanker-truck explosion in Arizona. Estimated soil excavation, waste hauling, and disposal costs to meet various clean-up criteria.

Developed and executed a soil sampling program at an amusement park in California to confirm soil quality prior to planned construction activities. Conducted employee interviews and a historic document review to identify areas of potential concern. Collected soil samples at a range of depths at locations where planned construction activities overlapped with areas of potential concern.

Modeled near-field and far-field plume characteristics of effluent discharged via diffusers from industrial facilities in the San Francisco Bay. Assisted in the development of a method to define a mixing zone for each diffuser that could be applied uniformly regardless of ambient water flow and tidal conditions.

Evaluated storm water runoff quality and quantity from an industrial facility in the Pacific Northwest to determine potential harm to receiving waters. Investigated the amount of dilution that would occur when site runoff mixed with storm water from the surrounding watershed, and modeled the size of the mixing zone and dilution at the point of discharge.

Estimated the cost of remediating historically contaminated soils for the purposes of land valuation. Determined construction costs for a site investigation, excavation activities, and waste hauling and disposal. Evaluated multiple removal scenarios based on potential hypothetical future land use for areas that exceeded risk-based TPH concentrations.

Provided an analysis of the timing and occurrence of how hazardous materials came to be located at a property in Waianae, Hawaii. Contamination included used lead-acid batteries; sandblast material; wrecked autos and associated petroleum; and oil, lubricants, painting wastes, and solvents. Additionally, several burn pits were located on the property. The site underwent an emergency remedial action following a raid by the EPA Criminal Investigation Division (CID).

Assisted in an evaluation of the metals distributions in sediments, soil, and dust in the upper Columbia River drainage basin. Numerous mines, mills, and smelters operated in this area. Metals contributions to the Columbia River system from various sources including mines, mills, and smelters, landslides, background, and other anthropogenic sources were considered. Chemical fingerprinting methods were employed for source identification.

Assessed sediment and nutrient loading to Kaelepulu Pond in Kailua, Hawaii, from grading activities at an adjacent construction site. Soil and nutrient loss from the site was estimated using the universal soil loss equation (USLE), as well as by the use of field data collected during storm events. Contributions of sediment and nutrients to Kaelepulu Pond from the construction site were evaluated with regard to sediment and nutrient loading from the greater watershed area. A comprehensive evaluation of site BMPs was conducted, which included comparison of the BMP plan to what was implemented in the field, and an assessment of BMP successes and failures during substantial rainfall events. This case settled at mediation July, 20, 2015.

Supported an analysis of apportionment of surface water contributions to the Kahala drainage system near Honolulu, Hawaii. A review of historic drainage canals, storm water best management practices, and stream hydrology were involved in the evaluation.

Worked with team members at Space and Naval Warfare System Command (SPAWAR) System Center Pacific on the scale-up approach, design, and fabrication of a benthic microbial fuel cell (BMFC) with a sustained power goal of 1 W to power Navy-relevant submersible electronics. Conducted multiple lab-scale BMFC experiments investigating power density variation relative to anode size, and organized and analyzed data from existing lab-scale and field-scale experiments to guide the scale-up approach. Fabricated a full-scale anode system (20 m2 anode surface area) to meet a fall 2012 deployment schedule.

CREDENTIALS & PROFESSIONAL HONORS

  • Ph.D., Environmental Engineering, University of Southern California, 2013
  • M.S., Environmental Engineering, University of Southern California, 2009
  • B.S., Chemical Engineering, University of California, Santa Barbara, 2007
  • USC Viterbi Undergraduate Mentoring Research Award, 2013

    USC Sonny Astani School of Civil and Environmental Engineering Best Teaching-Assistant Award, 2011

LICENSES & CERTIFICATIONS

Licensed Professional Engineer, California, #87757