Zeng’s research interests include the occurrence and fate of organic contaminants, formation and control of disinfection byproducts, public health implications of water reuse and environmental impacts of energy production. Zeng’s group combines controlled laboratory experiments with field work to study chemical processes occurring across diverse natural and engineered aquatic environments. His most recent work focuses on: (1) assessing transformation processes of organic contaminants and their interactions with dissolved and particulate constituents in natural waters and (2) characterizing sources of harmful byproducts to minimize their formation during drinking water purification and wastewater recycling to promote water sustainability while protecting public health.