Craig Ayres

Dr. Ayres has a background in environmental engineering with an emphasis on drinking water treatment processes, microbial pathogens in drinking water, engineered water systems, nanomaterial applications, and contaminant fate and transport. He has extensive laboratory experience cultivating bacteria and analyzing tolerance to treatment applications.

At Exponent, Dr. Ayres has applied his knowledge of drinking water disinfection and water distribution systems to various projects, including microbial contamination in the process water of an industrial facility and failed microbial quality control testing during installation of new drinking water service lines. He has also been involved in projects related to per- and polyfluoroalkyl substances (PFAS) in both the consumer product regulatory space and evaluation of capacity for removal at drinking water treatment facilities.

His doctoral thesis focused on the development of a point-of-use drinking water treatment strategy for the waterborne pathogen Legionella pneumophila and associated free-living amoebae that provide a replicative niche and increased treatment resistance. To overcome this resistance, he coupled microwave radiation with silver in the nanoparticulate or ionic form to induce localized heating or cellular membrane stress. In addition to his work on microbial inactivation, he specialized in the complex parasitic relationship between Legionella and free-living amoebae such as Acanthamoeba castellanii. Intracellular growth of Legionella within amoebae has been shown to enhance virulence and Dr. Ayres also investigated the drivers of this phenomenon and how infectivity related to treatment resistance.

He performed additional doctoral research with community water systems and incorporating nanotechnology into familiar and readily available technologies for point-of-use treatment. He was involved in research relating perceived and actual water quality through community survey responses and water quality testing, respectively. Dr. Ayres co-authored a review paper of existing and potential nanomaterial applications for the treatment of PFAS in drinking water. Dr. Ayres also studied SARS-CoV-2 detection in wastewater, assisting in the development of a routine monitoring strategy using digital polymerase chain reaction (dPCR).

Dr. Ayres earned his Ph.D. in Civil Engineering and M.S. in Environmental Engineering from the University of Texas at Austin. He earned his B.S. in Environmental Engineering from The Ohio State University. Prior to joining Exponent, Dr. Ayres also had three years of experience as an engineering consultant, focusing primarily on combined sewer overflow mitigation, stormwater and hydraulic modeling, and asset management.