He was also elected a member of the National Academy of Engineering in 2004 for pioneering the development of biofilm fundamentals and contributing to their widespread use in the cleanup of contaminated waters, soils, and ecosystems.

In 1992, Rittmann moved to Northwestern University to become the John Evans Professor and Area Coordinator of Environmental Engineering.

In 2005, he moved to Arizona State University to start the Center for Environmental Biotechnology in the newly formed Biodesign Institute.

[citation needed] Rittmann is one of the pioneers in developing and applying mathematical models of biofilms, which are microorganisms that grow attached to a solid surface.

Being major sinks for electrons and carbon, SMP and EPS have profound impacts on the performance of environmental biotechnologies in terms of effluent quality and the composition of the biomass.

Rittmann is the inventor of the Hydrogen-based Membrane Biofilm Reactor (MBfR),[3] which can be used to reduce and detoxify a wide range of oxidized pollutants commonly found in water: e.g., nitrate, perchlorate, chromate, selenate, trichloroethene, and uranyl.

[4] Rittmann’s photobioreactor team is working towards finding practical ways to utilize photosynthetic microorganisms to capture sunlight energy and convert CO2 into valuable feedstock for fuels and chemicals.

Working with Center colleagues César Torres and Sudeep Popat, Rittmann is advancing the fundamental science and technology bases for microbial electrochemistry, with the ultimate goal of using the technology to capture the energy in organic waste streams as valuable energy or chemical outputs.

The utilize high-throughput genomics, metabolomics, and quantitative modeling to understand the complex interactions among the many microorganisms and the human host, as well as to uncover means to manage the microbial communities towards good health outcomes.