It's #TechnicalTuesday and our Water & Wastewater Treatment Consultant Sarah Smith is exploring how extremophilic microorganisms could be used in water treatment to target specific contaminants.
There are often significant contamination risks associated with industrial activities, including heavy metal and organic pollutants which can present a significant risk to the health of water bodies, and their associated ecosystems. Often, these pollutants are difficult and expensive to deal with, and the conditions present in the water matrices in which they occur may be extreme e.g. acidic, alkaline, salty. So how can extremophilic microorganisms help to tackle these challenges?
Firstly, what is an extremophilic microorganism? Essentially, they are microbes that can survive and even thrive in extreme environmental conditions that seem like they would be completely inhospitable! Environments that are extremely hot, like hydrothermal vents are host to hyperthermophilic microbes that are quite happy in the >100°C temperatures, and there are even psychrophilic microbes that are found in permafrost and sea ice that relish in the sub-zero temperatures. Acidophilic microbes flourish in acidic environments like some of the hot springs in Yellowstone National Park, and halophilic microbes are those require very salty environments like salt lakes. There are even metallophilic and radioresistant microbes that take delight in high levels of heavy metals and ionizing radiation! The adaptation mechanisms that extremophiles employ to enable them to thrive in such harsh conditions can include the increased production of DNA repair proteins and changes to cell membranes, and often they develop novel metabolic pathways and produce highly stable enzymes capable of functioning in extreme conditions that can be useful for treatment of highly contaminated water.
How might extremophiles be used to help to treat contaminated water? Here are some examples of the potential applications for extremophilic microbes in helping to remove contaminants from water:
- Produced water resulting from oil and gas production processes is commonly salty and contaminated with hydrocarbons, and the salt concentration can pose a barrier to many microorganisms capable of degrading the organic contaminants. Halophilic microbes, however, are able to tolerate high degrees of salinity, and a number of halophilic species are actually able to degrade hydrocarbons, potentially presenting a mechanism to remediate produced water.
- Mine water presents an environmental hazard and can be very acidic and contaminated with high concentrations of heavy metals. Some species of acidophilic microbes are able to facilitate processes under low pH conditions that not only help to neutralize the water, but also to precipitate metals allowing them to be more easily removed, offering a potential mechanism to treat mine water.
- There are some alkaliphilic microbes (high pH-loving) that are capable of tolerating the alkaline conditions associated with some effluents from textile industries, and some strains have been shown to be able to degrade dyes associated with such wastes.
These are just some of the examples of how extremophilic microbes are able to facilitate some of the wonderful processes that might help to keep our water clean!