The Effects of Sand, Cloth, and No Tertiary Filtration on Microplastic Particles

Microplastics are ubiquitous contaminants that reside in all environments worldwide. From Artic ice down to small-scale river systems, these are just a few of the environments that are affected by these inherently small particles. Three WWTP’s within central Illinois were studied to see how their filtration methods reduced microplastics in wastewater. Two types of tertiary filtration (Sand and cloth) were studied to determine their ability at microplastic reduction. Microplastic reduction ranged from 42%-50% for cloth, and 25%-52% for sand. Our 3rd plant did not have tertiary filtration and reduced microplastics at a higher rate than WWTP’s that had tertiary filtration. Although the reduction of microplastics was low, the effluent from WWTP’s was diluting stream environments downstream from their discharge outlet. Factors like populations sized served by our WWTP’s was seen as a factor in influencing microplastic concentrations and abundances in WWTP Effluent. Although our WWTP’s are diluting stream microplastic concentrations, WWTP’s are still discharging up to 250,000 microplastics a day. The large volumes discharged over the course of a day by WWTP result in these high numbers of particles discharged. WWTP’s across the country are adequately reducing microplastics in wastewater, but they can be a concentrated discharge outlet of microplastics to our environment.