Research Interests
The basic task of an environmental engineer engaged in water quality management is the maintenance of adequate water supplies for the benefit of society. Aspects of both quality and quantity of water are very much at the forefront of today’s challenges in the face of a changing climate and diminishing resources. For example, being able to determine the origins of fecal pollution in urban waterways is becoming increasingly important as we aim to respond to natural and man-made disasters. Knowledge about the sources of microbial and other contaminants can help mitigate their impacts and facilitate risk assessment of exposure to drinking and recreational waters, Similarly, treatment of used water requires increasingly stringent and innovative technologies that build on the discovery and exploitation of microbiological processes, such as those found in the N and P cycle.

Through the development of new tools in the life sciences it has become possible to complete whole genome analyses of microorganisms in a short period of time. Bioinformatics tools, while lagging behind in the development of technical solutions to fast and” deep” sequencing technology, are being readied to accommodate the growing need of data compilation, management and interpretation. Across the developed world engineers have begun to interact with their counterparts in the natural sciences in a search for knowledge that can result in new technology for the treatment of water and used water.

As a researcher and educator steeped in both environmental engineering and life sciences disciplines, I strongly believe in studying fundamental biological and physico-chemical processes to develop new technology that is sustainable and market-ready in the long term. My vision for the School of Civil and Environmental Engineering (CEE) along with the Singapore Center on Environmental Life Sciences Engineering (SCELSE) is to train students in practical and theoretical aspects of what can truly be called environmental life sciences engineering (a new discipline coined by the directorate of SCELSE) and provide guidance to academic colleagues and postgraduate researchers at NTU.

In specific terms, my research program involves the following three thrusts:

a) Fundamental studies of biofilms and microbial communities in natural and engineered systems

The emphasis is on a complete spatial and temporal description of microbial aggregates involved in the removal of chemical constituents-of-concern using advanced imaging and pyrosequencing techniques.

b) Optimizing bioreactor treatment strategies

As chemical analytical techniques become more sophisticated, so does our knowledge about the occurrence of specific contaminants in the environment. The field of wastewater treatment has historically been based on general treatment goals using empirically derived methods in design. However, this system often fails to deliver specific treatment goals such as degradation of a specific contaminant without affecting general treatment performance. An ever increasing number of chemical contaminants are being detected in treated used water effluent and in biosolids. Therefore, knowledge of the removal mechanisms of specific contaminants as well as an in-depth understanding of overall microbial community dynamics and expression of functional genes in a reactor is necessary.

c) Protecting Public Health in Singapore

For several years I have been working on the quantitative detection of pathogens in natural (e.g. storm) waters and biosolids using procedures based on the polymerase chain reaction (PCR). Much of this research is driven by the growing realization in the scientific and professional community that for a variety of reasons standard microbial indicators like E. coli, fecal coliforms and enterococci may be inadequate predictors of recent fecal contamination in recreational waters.