Prof Njau is the team leader of BioInnovate Africa supported project on New integrated methods for industrial wastewater treatment. He is an Associate Professor and Head of the department of Water Resources and Environmental Science and Engineering at the Nelson Mandela African Institute of Science and Technology, Tanzania. He is also a consultant on environmental issues. His research interests are in constructed wetlands for pollution control, reactor engineering and optimisation, and smart solutions for environmental management.
He has led research groups on water purification and biogas systems. He holds a Ph.D in Environmental Engineering from University of Technology, Eindhoven, Netherlands); a Master of Science in Chemical Engineering from Norwegian Institute of Technology, Norway; and a Bachelor of Science in Process Engineering from University of Dar-es- Salaam, Tanzania.