New approaches to microbial ecology in biological phosphorus removal systems

Wastewater treatment can attenuate water scarcity, pollution and play a key role in the Bioeconomy. Using biological wastewater treatment processes can deliver effective treatment, often promoting higher efficiencies and acting as a source of value-added compounds, such as phosphorous and polyhydroxyalkanoates, that can be recovered from the microbial communities in these systems. In particular phosphorus can be both a pollutant, contributing towards eutrophication, and a valuable resource with a shortage of extractable phosphorus resources predicted within the next 100 years. Recovery of this nutrient from wastewater is estimated to be able to meet 22% of global phosphorus demand. 1 Enhanced Biological Phosphorus Removal (EBPR) is often considered one of the most attractive processes for phosphorus removal from wastewater, one that does not require the addition of chemical precipitants, and with clear synergies with phosphorus recovery technologies.2 The uptake of phosphorus is performed mainly by a group of bacteria named polyphosphate-accumulating organisms (PAOs). However, effective phosphorus removal is often compromised by the population dynamics of the existing mixed microbial communities following variability in operational and environmental conditions, competition between different organisms, predation and infection by bacteriophages. Also, due to low concentration of carbon source in the wastewater, the process often requires the addition of carbon feedstocks such as acetate, which contribute to the overall process cost and carbon footprint. Hence, to ensure the resilience and effectiveness of this technology, further research is needed on the impact of process operation and different microbial stresses on the microbial ecology and phenotype of PAOs, especially 'in the wild', i.e. in real full-scale mixed liquors.
This project will focus on developing and using innovative approaches for the study of the microbial ecology and function of the mixed communities present in biological wastewater treatment systems. Specifically, it will explore three key aspects applied to EBPR systems:
1 - Importance of PAO abundance on EBPR performance. This will be explored by artificially bio-augmenting real mixed-liquor samples with enrichment of key organisms in EBPR, mapping the ratio of different PAO organisms in relation to performance, in collaboration with Wessex Water for sample procurement;
2 - Development of techniques to identify the phage populations in EBPR systems and cultivate them. These techniques will be used to develop a new phage therapy methodology to knock-out specific populations of the mixed microbial cultures in EBPR and hence investigate their function;
3 - In collaboration with Anglian Water, investigate the use of glycerol as a viable source of supplementary of carbon in EBPR, its effect on the microbial ecology of the system and its efficiency. Glycerol is a by-product of the biodiesel industry with 40% carbon, low value as feedstock and that needs to be properly treated and discharged. Hence, glycerol would be an attractive alternative to other feedstocks used in wastewater treatment.
Ultimately, even though the project is focused on the system of EBPR, most of the approaches developed can be then applied to other biological systems.

1. Cordell, D., Rosemarin, A., Schroeder, J. J. & Smit, A. L. Towards global phosphorus security, A systems framework for phosphorus recovery and reuse options. Chemosphere 84, 747-758 (2011).
2. Oehmen, A. et al. Advances in enhanced biological phosphorus removal, From micro to macro scale. 41, 2271-2300 (2007).

The Centre for Doctoral Training (CDT) in Sustainable Chemical Technologies (SCT) at the University of Bath will place fundamental concepts of sustainability at the core of a broad spectrum of research and training at the interface of chemical science and engineering. It will train over 60 PhD students in 5 cohorts within four themes (Energy and Water, Renewable Resources and Biotechnology, Processes and Manufacturing and Healthcare Technologies) and its activities and graduates will have potential economic, environmental and social impact across a wide range of beneficiaries from academia, public sector and government, to industry, schools and the general public.

The primary impact of the CDT will be in providing a pool of highly skilled and talented graduates as tomorrow's leaders in industry, academia, and policy-making, who are committed to all aspects of sustainability. The economic need for such graduates is well-established and CDT graduates will enhance the economic competitiveness of the UK chemistry-using sector, which accounts for 6m jobs (RSC 2010), contributing £25b to the UK economy in 2010 (RSC 2013). The Industrial Biotechnology (IB) Innovation and Growth Team (2009) estimated the value of the IB market in 2025 between £4b and £12b, and CIKTN (BIS) found that "chemistry, chemical engineering and biology taken together underpin some £800b of activity in the UK economy".

UK industry will also gain through collaborative research and training proposed in the Centre. At this stage, the CDT has 24 partners including companies from across the chemistry- and biotechnology-using sectors. As well as direct involvement in collaborative CDT projects, the Centre will provide an excellent mechanism to engage with industrial and manufacturing partners via the industrial forum and the Summer Showcase, providing many opportunities to address economic, environmental and societal challenges, thereby achieving significant economic and environmental impact.

Many of the issues and topics covered by the centre (e.g., sustainable energy, renewable feedstocks, water, infection control) are of broad societal interest, providing excellent opportunities for engagement of a wide range of publics in broader technical and scientific aspects of sustainability. Social impact will be achieved through participation of Centre students and staff in science cafés, science fairs (Cheltenham Science Festival, British Science Festival, Royal Society Summer Science Exhibition) and other events (e.g., Famelab, I'm a Scientist Get Me Out of Here). Engagement with schools and schoolteachers will help stimulate the next generation of scientists and engineers through enthusing young minds in relevant topics such as biofuels, solar conversion, climate change and degradable plastics.

The activities of the CDT have potential to have impact on policy and to shape the future landscape of sustainable chemical technologies and manufacturing. The CDT will work with Bath's new Institute for Policy Research, through seminars, joint publication of policy briefs to shape and inform policy relevant to SCT. Internship opportunities with stakeholder partners and, for example, the Parliamentary Office of Science and Technology will provide further impact in this context.