Dr Raffaella Villa

Job: Reader in Environmental Engineering

Faculty: Technology

School/department: School of Engineering and Sustainable Development

Address: De Montfort University, The Gateway, Leicester, LE1 9BH, United Kingdom

T: 0116 255 1551

E: raffaella.villa@dmu.ac.uk

W: dmu.ac.uk


Personal profile

Dr Raffaella Villa joined De Montfort University in 2019 as Reader in Environmental Engineering. Prior to that she worked at Cranfield, Stirling, Exeter and the University of Milan (Italy).

Raffaella has worked on microbial bioengineering for the last 20 years. Her major contributions relate to the delivery of the next generation biotechnological processes that combine protection and production for a more circular bioeconomy, such as bioremediation and high-value products from waste. This is achieved by understanding the common science in the two areas (protection and production) on how to control and enhance specific functions of microbial communities by manipulating operative conditions to increase process yields and stability, with increasing emphasis on the concept of the “waste biorefinery”.

Raffaella has published over 60 research papers, books and conference proceedings with substantive contributions to waste biotransformations, bioremediation and anaerobic digestion.

Research group affiliations

Institute of Energy and Sustainable Development (IESD)

Publications and outputs 

  • On the potential of on-line free-surface constructed wetlands for attenuating pesticide losses from agricultural land to surface waters
    On the potential of on-line free-surface constructed wetlands for attenuating pesticide losses from agricultural land to surface waters Guymer, I.; Villa, R.; Jefferson, B.; Ramos, A.; Whelan, M. J. Pesticides make important contributions to agriculture but losses from land to water can present problems for environmental management, particularly in catchments where surface waters are abstracted for drinking water. “On-line” constructed wetlands have been proposed as a potential means of reducing pesticide fluxes in drainage ditches and headwater streams. Here, we evaluate the potential of two free-surface constructed wetland systems to reduce pesticide concentrations in surface waters using a combination of field monitoring and dynamic fugacity modelling. We specifically focus on metaldehyde, a commonly-used molluscicide which is moderately mobile and has been regularly detected at high concentrations in drinking water supply catchments in the UK over the past few years. We also present data for the herbicide metazachlor. Metaldehyde losses from the upstream catchment were significant with peak concentrations occurring in the first storm events in early autumn, soon after application. Concentrations and loads appeared to be minimally affected by transit through the monitored wetlands over a range of flow conditions. This was probably due to short solute residence times (quantified via several tracing experiments employing rhodamine WT – a fluorescent dye) exacerbated by solute exclusion phenomena resulting from patchy vegetation. Model analyses of different scenarios suggested that, even for pesticides with a relatively short aquatic half-life, wetland systems would need to exhibit much longer residence times (RTs) than those studied here in order to deliver any appreciable attenuation. If the ratio of wetland surface area to the area of the contributing catchment is assumed to be a surrogate for RT (i.e. not accounting for solute exclusion) then model predictions suggest that this needs to be greater than 1% to yield load reductions of 3 and 7% for metaldehyde and metazachlor, respectively. The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.
  • From full-scale biofilters to bioreactors: engineering biological metaldehyde removal
    From full-scale biofilters to bioreactors: engineering biological metaldehyde removal Rolph, Catherine A.; Jefferson, Bruce; Brookes, Adam; Choya, Andoni; Iceton, Gregg; Hassard, Francis; Villa, R. Polar, low molecular weight pesticides such as metaldehyde are challenging and costly to remove from drinking water using conventional treatment methods. Although biological treatments can be effective at treating micropollutants, through biodegradation and sorption processes, only some operational biofilters have shown the ability to remove metaldehyde. As sorption plays a minor role for such polar organic micropollutants, biodegradation is therefore likely to be the main removal pathway. Here, the biodegradation of metaldehyde was monitored, and assessed, in an operational slow sand filter. Long-term data showed that metaldehyde degradation improved when inlet concentrations increased. A comparison of inactive and active sand batch reactors showed that metaldehyde removal happened mainly through biodegradation and that the removal rates were greater after the biofilm was acclimated through exposure to high metaldehyde concentrations. This suggested that metaldehyde removal was reliant on enrichment and that the process could be engineered to decrease treatment times (from days to hours). Through-flow experiments using fluidised bed reactors, showed the same behaviour following metaldehyde acclimation. A 40% increase in metaldehyde removal was observed in acclimated compared with non-acclimated columns. This increase was sustained for more than 40 days, achieving an average of 80% removal and compliance (< 0.1 µ L-1) for more than 20 days. An initial microbial analysis of the acclimated and non-acclimated biofilm from the same filter materials, showed that the microbial community in acclimated sand was significantly different. This work presents a novel conceptual template for a faster, chemical free, low cost, biological treatment of metaldehyde and other polar pollutants in drinking water. In addition, this is the first study to report kinetics of metaldehyde degradation in an active microbial biofilm at a WTW. The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.

Research interests/expertise

Dr. Villa's research interests include:

applied microbial processes across the fields of wastewater treatment (bioremediation) and energy from waste (anaerobic digestion and algae);

waste biotransformation;

environmental engineering.


PGCert in Academic Practice

PhD in Food Biotechnologies, Universitá di Milano (Italy)

BSc and MSc in Food Sciences and Technologies, Universitá di Milano (Italy)

Honours and awards

Personal Marie Curie Post-Doctoral Fellowship (EU FP5), Stirling University 2000

MIUR (Ministry of Education, Universities and Research) Personal Advancement Fellowship (1995)

Membership of external committees

Member of the Editorial Board of ICE Water Management (https://www.icevirtuallibrary.com/toc/jwama/current)

Editor in Chief of Environmental Technology Reviews (https://www.tandfonline.com/toc/tetr20/current)

Membership of professional associations and societies

Member of the Society for Applied Microbiology

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