Developing an Event Prediction and Correction Framework for Microbial Management in Drinking Water Systems.

Drinking water is teeming with microbial life. In fact, drinking water can contain anywhere from millions to hundreds of millions of microbial cells per litre, all with extremely different evolutionary histories and abilities. For example, microbes can (1) affect human health by causing diseases, (2) corrode infrastructure, and (3) also deteriorate the aesthetic quality of water. In an effort to limit these detrimental scenarios, drinking water companies invest significant amounts of labour, energy, and money towards limiting microbial presence through the use of disinfection. Though disinfection approaches have been effective in reducing the incidence of waterborne diseases, they are not 100% successful and microbial communities persist. As a result, drinking water companies also engage in microbial management by implementing rigorous sampling programs with the goal of early detection of microbial contamination events. These early detection programs are reactive in nature and can only detect a problem once it has occurred and are limited to informing strategies that try to mitigate the imminent risk posed to consumers. Further, they also typically focus only on pathogenic microorganisms and ignore all other microbial impacts (e.g. corrosion causing bacteria that deteriorate water supply pipes).

These inefficiencies in microbial management can be remedied by transitioning from the existing Early Event Detection and Mitigation approach to an Event Prediction and Correction (EPC) framework in the drinking water industry.

An EPC framework would enable the drinking water companies to predict the risk presented by an array of detrimental microbes (disease/corrosion/odour/taste causers) over operationally relevant time-scales and allow for the initiation of measured and proactive corrective action strategies to eliminate this risk before it is manifested. The key towards developing a robust EPC framework would be to (1) identify key locations in the drinking water system that can serve as predictive indicators, (2) quantify the temporal dynamics of these locations and how it correlates with the whole drinking water system, and (3) develop statistical models informed by microbial community data to predict contamination events. In this study, we will engage in an extensive effort to characterize the bacterial, protozoal, and fungal communities at multiple drinking water systems in Scotland. This will be followed by a long-term sampling campaign at one representative drinking water system to quantify the spatial and temporal dynamics of the drinking water microbiome. By tapping into the on-going nucleic acid revolution, we will be able to describe the drinking water microbial communities at an unprecedented level of detail. This detailed quantitative insight will be used to parameterize and shape a statistical model that describes assembly of complex microbial communities and predicts their fate in the drinking water system.

This project has several anticipated benefits over a range of time-scales. In the short-term, this project will substantially improve our understanding of the drinking water microbial communities, which has been traditionally under-studied. In the medium-term, it will enable the predictive management of the drinking water systems, which will help prevent microbial contamination problems, rather than tackle them once they have occurred which can be risky, expensive, and laborious. Further, predictive models may also allow us to isolate and treat sources of microbial risk within the drinking water treatment plant, thus preventing its entry into the distribution system. Over the medium-long term, we anticipate that building a predictive microbial management capacity in the drinking water sector will enable us to beneficially manipulate the drinking water microbiome to transform the way we treat and deliver water.

In the short-term (1-5 years), this research will improve our understanding of the drinking water microbiome by making substantial contributions to the knowledgebase being generated in the UK (primarily through EPSRC investments), Europe and the US. This impact is significant given the field of drinking water microbial ecology is surprisingly data-deprived (only 620 publications since 1995 compared to 5310 in wastewater, more than 10,000 in soils, marine environments [ref1]). This poor understanding of the drinking water microbiome is unacceptable considering other research areas that impact human health are being transformed by the technological breakthroughs that have occurred in the field of molecular microbial ecology over the last 5 years (e.g. high throughput sequencing). For example, the human microbiome consortium alone has published more than 400 papers since 2009. I have already started to address this shortcoming, by conducting one of the most extensive surveys of a drinking water system in USA. This project will enable me to continue this effort by systematically studying the drinking water microbiome across Scotland.

In the medium term (5-10 years), I envision that the outcomes of this project will serve as a primer for a new research area in the drinking water field-Predictive Microbial Ecology. As a first step, this project will incorporate microbial community dynamics into a statistical model that can be used for microbial management in the drinking water industry. The ability to predict microbial community dynamics is critical for any biologically active engineered system and will inevitably lead towards efforts to manipulate the drinking water microbiome. Herein, lies the biggest transformational promise and this will undoubtedly attract a multi-disciplinary group of scientists into the drinking water field-which is our best bet at innovation within an industry that has seen little innovative change in more than a century (except, for disinfection). In its National Infrastructure Plan released in 2011, the UK government indicated that approximately £250 billion (beginning in 2015) would be invested towards improving the country's infrastructure. A sizeable portion (8-10%) of this will be directed towards improving the resilience of the UK water infrastructure towards imminent challenges such as climate change, population growth and redistribution, and the resulting war stress. It would behove the drinking water community to prepare for these investments by developing new solutions and approaches; rather than recycling and retrofitting out-dated ideas and technologies. One such opportunity is presented by this project.

In the long-term (10-50 years), I believe that the transformative potential of the predictive microbial ecology in the drinking water field will be immense. It will enable the drinking water sector to harness one of nature's greatest resource, microbial diversity and its metabolic potential, to permanently change how water is treated and delivered. For example, instead of using disinfection to try and kill pathogenic microbes at the plant; we will be able to manipulate the drinking water microbiome to ensure the presence of beneficial microbes that out-compete and eliminate detrimental microbes on a continuous basis in the entire drinking water system. This will mean that public will no longer be exposed to chronic doses of harmful disinfection by products. This is just one example how we may manipulate the drinking water microbiome for our benefit, using predictive microbial ecology. Given the remarkable diversity of microbial communities, such beneficial possibilities are endless. The ability to predict and manipulate the drinking water microbiome will allow us to meet our goal of providing truly "Safe and Healthy Drinking Water".

[ref1] Source: ISI Web of Knowledge using key words "microbial community" in combination with drinking water or wastewater or soils or marine.