Reuse of Water Contaminated by Microplastics, the Effectiveness of Filtration Processes: A Review

Water treatment generally does not specifically address the removal of microplastics (MPs). Nevertheless, treatment plants process water effectively, and the number of synthetic microparticles in effluents is usually very low. Still, discharge volumes from water-treatment plants are often elevated (reaching around 10(8) L/day), leading to the daily discharge of a substantial number of MPs and microfibers. Furthermore, MPs accumulate in the primary and secondary sludge, which in the end results in another environmental problem as they are currently used to amend soils, both for cultivation and forestry, leading to their dispersion. Something similar occurs with the treatment of water intended for human consumption, which has a much lower but still significant number of MPs. The amount of these pollutants being released into the environment depends on the processes that the water undergoes. One of the most-used treatment processes is rapid sand filtration, which is reviewed in this article. During the filtration process, MPs can break into smaller pieces, resulting in a greater number of plastic particles which mainly accumulate in sewage sludge. Thermal processes, such as incineration, carried out in facilities with the best available techniques in practice, could guarantee the safe disposal of highly MP-contaminated sewage sludges.

Automated summary

Water treatment usually does not specifically address the removal of microplastics, but treatment plants can effectively process water and reduce the number of synthetic microparticles in effluents. However, the discharge volumes from water treatment plants are often high, resulting in the daily release of a significant amount of microplastics and microfibers. Microplastics also accumulate in sludge and can disperse when used to amend soil. One of the most commonly used treatment processes, rapid sand filtration, can break microplastics into smaller pieces and increase the plastic particle count in sludge. Thermal processes, such as incineration, conducted using the best available techniques, can ensure the safe disposal of highly microplastic-contaminated sludge.