Microplastics have been found in land, air, freshwater, effluent from a wastewater treatment plant and even in tap water and bottled water. The small plastic particles (less than 5 mm) pose a threat to the freshwater and marine ecosystem including fish and mussels due to potential adsorption of hydrophobic contaminants like polychlorinated biphenyls (PCBs) into the body of microplastics depending on size and shape of particles. The land application of sewage sludge along with the sludge produced from water treatment process (sedimentation tank) is a large source of microplastics pollution in freshwater. The run off resulted from precipitation and high wind cause transport of microplastics from a place far from where it is produced. This is an acute problem, particularly for the regions of the world where sewage is not even treated up to the secondary treatment level and the target effluent quality is poorly managed. So, the question is: can microplastics be controlled in a watershed and if so, how?
This is a question that everyone is struggling with, and there are no definitive answers. I think it's likely that some technological methodologies will continue to develop that enable us to do some removal in future. More degradable polymers will be developed and move through into products, causing similar problems but for much less time. There appear to be several interesting microbiological avenues that offer digestion of troublesome plastics too. There is also a role for effective capture of waste plastics, so that inadvertent loss to the environment is really infrequent.
Ultimately though, the most powerful tools are changing consumer expectations and behaviors so that fewer macroplastics and microplastics are produced, discarded and reach the environment. On top of that perhaps is considering a more realistic financial value being placed on plastics, reflecting their life cycle impacts and environmental issues and not just the production cost.
Thank you, Prof. Andy Smith for the wonderful thoughts. I was thinking along the line of treatments. We can improve filtration technology using microfiltration, nanofiltration, and even membrane treatment, etc. It will increase the cost of treatment. The sludge from a wastewater treatment plant, however, need to be controlled efficienctly. Microbiological treatment of plastics would be a feasible process to manage microplastics. I would like to hear more about that avenue. Thanks!
Hi,
Try to look to this paper: Microplastic Contamination in Freshwater Environments: A Review, Focusing on Interactions with Sediments and Benthic Organisms
Maybe it will help to find some answers.
https://www.mdpi.com/2076-3298/7/4/30
L.
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