Optimisation of thermally enhanced granular activated carbon biofiltration for decentralised drinking water treatment
Supervisor: Dr Anastasiia Kostrytsia and Dr Fabien Cholet
The development of low-cost and low-energy decentralised water treatment technologies for remote communities in Scotland is primordial in an effort to reach the zero-carbon economy target. Surface waters are the main sources for drinking water production in Scotland. Organic matter (OM) within surface water deteriorates water quality (taste and odour) and contribute to microbial regrowth in drinking water systems and the presence of pathogenic bacteria poses a threat to public health.
The removal of OM via biofiltration is an appealing technology because of its lower chemical and energy consumption compared to conventional methods. Biofilters packed with granular activated carbon (GAC) can remove pollutants via both physico-chemical (adsorption) and biological mechanisms. Microbial communities that establish within the biofilters are responsible for the biological degradation of OM and can be engineered to achieve better performance via the selection of operating and environmental parameters.
Surface water in Scotland is generally at temperatures below 10°C. These relatively low temperatures can be detrimental to the performance of the biofiltration process. In order to increase the kinetics of organic matter degradation, the thermal enhancement of biofiltration is proposed in this project. Sets of 30-cm GAC biofilters will be operated at 10°C and 20°C in respective temperature-controlled rooms. We hypothesise that higher OM removal will be achieved at 20°C. To test this, OM in influent and effluent water will be measured weekly over the course of a 12 weeks biofiltration experiment. The undergraduate student will be involved in weekly collection of influent and effluent water and routine physio-chemical measurements, data collection and pre-processing.
The effect of higher temperature on the microbial community in the effluent water and in particular the abundance and survival of bacterial pathogens will also be monitored throughout this project. To do so, a combination of molecular and culture-based methods will be employed. Total DNA and DNA originating from live-cells only will be extracted from filtered influent and effluent samples, and pathogens will be quantified from both DNA pools to estimate their survival. For comparison, traditional plate count methods will also be used. The student will be involved in water filtration for molecular analysis, media preparation and plate counting.