In-reservoir destruction of Blue-Green Algae and their toxins

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One of the greatest global challenges currently facing human-kind is access to reliable safe clean drinking water. This is particularly acute in developing countries where human activities often adversely impact water quality. While the earth is known as the blue planet with 71% of its surface covered in water, nearly all of this is seawater and not suitable for human consumption or is utilised in industrial and agricultural processes. Only a tiny proportion of the earth's water is freshwater (about 3%) and of this less than 1% is available for use, since much of the remainder is frozen at the poles or in glaciers. Water levels and quality in drinking water reservoirs across the globe are seriously depleted with the United Nation predicting that 1.8 billion people will suffer serious recurrent water shortages by 2025 and two thirds of the population living in areas of water stress.Of the water that remains in these depleted reservoirs, nutrient (nitrate and phosphate) levels from agriculture, industry and domestic waste are found to be high resulting in the mass growth of blue-green algal blooms along with the production and release of dangerous toxins. These toxins can cause acute and chronic symptoms in humans and animals resulting in ill-health, fatalities and cancers. When present in high numbers traditional water treatment often fails to eliminate the blue-green algal cells resulting in human exposure. Furthermore, the toxins they produce are also very stable during treatment allowing them to pass unaltered into drinking water. Innovative water treatment to eliminate these problems which uses light and a simple catalyst (TiO2 photocatalysis) has been pioneered by Professor Linda Lawton (Environmental Microbiologist - RGU) and Professor Peter Robertson (Chemical Engineer - QUB). We have successfully demonstrated the rapid and effective removal of 4 out of the 6 classes of toxins (evidence suggests the remaining 2 classes, saxitoxins & BNAA, will be easily destroyed as they are more simple chemical structures). Furthermore, we have also shown that the same treatment is effective against harmful microbes in water.We have extensively evaluated this exciting technology both in the laboratory and on a pilot scale with considerable interest from water utilities in seeing the full implementation within the provision of drinking water. One limiting factor has been developing a simple strategy to expose and illuminate catalyst in contact with water while ensuring that the catalyst can be readily removed. The most efficient destruction has been found for nano-particulate catalysts which cannot easily be removed from water. We aim to transform the approach to dealing with blue-green algal contamination of reservoirs by developing and testing exciting new photocatalytic treatment pods which are continually powered by integrated, floating solar panels which drive low energy LEDs. Professor John Irvine (Electrochemist - St Andrews) will bring his world leading expertise in catalyst modification and characterisation along with electro-optimisation. Dr Christine Edwards (Biotechnologist - RGU) along with Professor Lawton have led the field in the production and detection of cyanotoxins and we will collaborate with leading scientists in Brazil where reservoirs are currently extremely depleted and suffering from significant blue-green algal blooms and their associated toxins. This collaboration will allow us to test the in-reservoir deployment of our novel treatment system in water bodies which are consistently contaminated with blue-green algae and in an environment with excellent solar irradiation with which to drive the very low running cost treatment.On completion of this research we will launch a fully scalable in-reservoir water treatment system which will be transferable to any developing or developed country to eliminate hazardous blue-green algal blooms, other pathogens and a wide range of toxic pollutants.