Smart Management of Microplastic Pollution

Environmental Monitoring

There is a lack of information regarding microplastic pollution from point sources such as wastewater discharge and non-point sources such as degradation of plastic litter and storm water runoff. Compared to conventional methods, the IoT sensing technology, developed by the project team, provides a more rigorous platform for monitoring and sourcing microplastics inputs.

The IoT sensors will provide abundant critical information for microplastics monitoring, including the size, chemical composition, and aging/history of microplastics, as well as the correlation to the location and weather conditions.

In addition to microplastics monitoring, weather and environmental conditions such as temperature and pH will be simultaneously monitored. The availability of this information allows for targeted mitigation for pollution prevention in both Williamston and Pontiac. These mitigation efforts include the use of laundry bags and green stormwater infrastructure. Effectiveness will be evaluated by monitoring the change of microplastics inputs before and after the mitigation in both pilot cities.

Dr. Zhang’s research group published one research article in the journal of Science of the Total Environment: “Removal efficiency of micro- and nanoplastics (180 nm–125 μm) during drinking water treatment”

This study investigated the removal efficiency of micro- and nanoplastics (180 nm–125 μm) during drinking water treatment, particularly coagulation/flocculation combined with sedimentation (CFS) and granular filtration under ordinary working conditions at water treatment plants (WTPs). It also studied the interactions between biofilms and microplastics and the consequential impact on treatment efficiency. Generally, CFS was not sufficient to remove micro- and nanoplastics. The sedimentation rate of clean plastics was lower than 2.0% for all different sizes of plastic particles with coagulant Al2(SO4).

Even with the addition of coagulant aid (PolyDADMAC), the highest removal was only 13.6% for 45–53 μm of particles. In contrast, granular filtration was much more effective at filtering out micro- and nanoplastics, from 86.9% to nearly complete removal (99.9% for particles larger than 100 μm). However, there existed a critical size (10–20 μm) where a significant lower removal (86.9%) was observed. Biofilms were easily formed on microplastics.

In addition, biofilm formation significantly increased the removal efficiency of CFS treatment from < 2.0% to 16.5%. This work provides new knowledge to better understand the fate and transport of emerging micro- and nanoplastic pollutants during drinking water treatment, which is of increasing concern due to the potential human exposure to micro- and nanoplastics in drinking water.

Wayne State University

Wayne State University Department of Civil & Environmental Engineering
5050 Anthony Wayne Drive, Detroit, MI 48202