Using algae to clean up mine water

Dr Chris Bryan and Dr Mark van der Giezen, University of Exeter are working alongside partners from Bath, Bristol and Cardiff to address the global problem of polluted mine water. The research of AVaRICE aims to improve the health and environment of millions of people around the world through an innovative process that uses algae to clean up polluted mine water, harvesting precious heavy metals and producing biofuels in the process.

How are you tackling this problem, and what is the solution?

Metal contaminated mine waste. Image credit: Mark van der Giezen.
Metal contaminated mine waste. Image credit: Mark van der Giezen.

Polluted mine water is a global problem. Costly clean-up and remediation activities are often inappropriate because of their high cost and low return.

We have taken untreated mine water samples from the Wheal Jane tin mine in Cornwall and grown algae in them, in an attempt to remove pollutants such as arsenic and cadmium. We then convert the algae via a process called hydrothermal liquefaction. This produces a water, gas, oil and solid phase and the heavy metals end up in concentrated form in the solid phase. We can use the oil phase (also called bio-crude) to make biofuels.

Our work showed that the polluted mine water can be used to grow algae. Tests demonstrated that the metals led to greater conversion of biomass to bio-crude, this is particularly noteworthy given the current interest in sustainable biofuel production. The water phase from the process contained much of the nitrogen and phosphorus from the algal biomass and we successfully used this as a fertiliser to boost algal growth.

This technology can be applied to any type of mine waste and also be used to clean up metal contaminated industrial effluents. By making the clean-up process pay for itself, we improve the health and the environment of millions of people around the world.

How has being part of GW4 benefited your research community?

Large-scale algal cultures growing on mine waste. Image credit: Mike Allen, PML.
Large-scale algal cultures growing on mine waste. Image credit: Mike Allen, PML.

AVaRICE has brought together expertise in a range of disciplines from molecular ecology to chemical engineering. We have also utilised facilities from across the four institutions. By drawing on each other’s strengths and complementing key expertise, we have made significant progress in proving the concept of AVaRICE. This could not have been delivered by a single group or institution.

Mine samples are incubated in Winogradsky columns to study microbial diversity. Image credit: Mike Allen, PML
Mine samples are incubated in Winogradsky columns to study microbial diversity. Image credit: Mike Allen, PML

GW4 funding has enabled us to employ a post-doctoral research fellow and a research assistant. Both have spent significant time in the field (including the Wheal Jane, Wheal Maid and County Adit sites) and working in partner laboratories.

This has provided an excellent opportunity for continual knowledge transfer amongst the partners and resulted in the cross fertilisation of concepts and ideas related to the project.

We have also purchased a pilot-scale algal cultivation system that we can employ on site to apply the AVaRICE concept at a suitable scale to test process behaviour and economics.

As the community has grown, partners have joined to pursue common interests linked to or outside of the AVaRICE concept, leading to many other joint research avenues. Our recent success in securing BBSRC funding to work with an industrial partner, applying our innovative process to their waste stream is another demonstration that we are on the right track with our work and are making an impact.

Plans for the future?

Euglena from electron micrograph. Photo credit: Mike Allen and Steve Gschmeissner, PML
Electron micrograph of Euglena, a photosynthetic protist isolated from our mine site. Photo credit: Mike Allen and Steve Gschmeissner, PML.

Huge progress towards proving the concept of the AVaRICE process has been made. We have demonstrated our concept at a laboratory scale. Challenges remain when we upscale our process to industrial level but new partnerships have been formed that will enable these exciting new steps. We are highly motivated and determined to pursue the development of AVaRICE further.

There has been significant national and international interest from the media, industrial and academic partners. Currently we are in discussion with various potential partners and collaborators to apply our innovate process to a variety of waste streams in the hope we can make a change.

GW4 Community leads
University of Bath: Christopher Chuck
University of Bristol: Tom Scott
Cardiff University: Devin Sapsford
University of Exeter: Chris Bryan
Plymouth Marine Laboratory: Mike Allen

PARTNERS                                                                                                        RELATED LINKS
Plymouth Marine Laboratory                                                                        avarice.org.uk
Coal Authority                                                                                                  @AVaRICE_gw4

View the project summary