Nature's water cleansers

10 June 2015 | Research
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Microbes have been found to be nature's pollutant cleaners

NUS scientists have found how raw water that collects in channels within megacities gets cleaned-up naturally, with help from multitudes of microbes.

This discovery shows the possibility of harnessing microbes in cleansing Singapore's waterways and serving as water quality indicators.

The study spanning seven years unveiled that canals for channelling rainwater harbour microbial communities. These microbes have the ability to get rid of nutrients, organic pollutants and metals in raw water. The constituents ' present in trace levels below the US-Environmental Protection Agency drinking water standards in Singapore raw water ' are further removed during water treatment processes.

Researchers from the NUS Environmental Research Institute (NERI) and the Singapore Centre for Environmental Life Sciences Engineering (SCELSE) ' a joint Research Centre of Excellence between NUS and the Nanyang Technological University ' believe that such pollutant-busting ability of microbes could be exploited for treating raw water before it is processed. In bioremediation, naturally occurring organisms are used to break down organic pollutants.

The collaborative work involving institutions in Singapore, Australia and the US, together with Singapore's national water agency PUB, was carried out around the Ulu Pandan catchment area. By extracting the DNA and RNA of the microbes, the team identified 2,100 members of the whole microbial community and their functions. The investigators also determined that aluminium, copper and potassium were critical factors influencing the community's ability to perform its ecological "cleansing properties.

The breakthrough work, published in Environmental Science & Technology, was headed by Associate Professor Sanjay Swarup, Deputy Director of NERI and Research Director at SCELSE. The project also compared microbial communities in residential and industrial watershed systems, which differ in functions. The observation demonstrated that various land use could influence the types of microorganisms and their capabilities.

Said Dr Gourvendu Saxena, Research Fellow at NERI and SCELSE: "Knowing what the microbes are doing provides information on what they are responding to. These marker-based microbial functions provide a higher resolving power than chemical markers that are currently in use.

Assoc Prof Swarup pointed out that "with the support of government administrators, environmental sustainability could be achieved naturally through science, creating a better living environment for both man and nature.

The research framework created in this study could be easily applied by other cities which face growing demand for efficient, sustainable solutions to water needs in urban areas. It is being adopted by the international World Harbour Project, a network of researchers and managers that aims to bring the best practices in understanding and managing ecological pressures in harbours across the world.

The team plans to explore the effects of plants on microbial communities, as well as different waterways designs and sensors to achieve optimal settings and parameters.