Michael H. Gerardi holds an M.S. in Biology from James Madison University and has served as an expert witness for the US EPA on nitrification and denitrification. In addition to the prior books in Wiley's Wastewater Microbiology series, he has authored more than one hundred technical publications and has provided wastewater microscopy and consulting services for numerous municipal and industrial wastewater treatment plants. He is an independent consultant and has developed wastewater biology courses for Penn State University and has present course to an audience of over 10,000 operators.