We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Facial Animation Based on 3D Scans and Motion Capture
Summary
This meta-analysis of 78 wastewater treatment plants across 57 studies found that WWTPs achieve over 90% total microplastic removal, with oxidation ditch, biofilm, and conventional activated sludge processes outperforming other methods. Membrane bioreactors were the most effective secondary treatment, and film, foam, and fragment microplastics were easier to remove than fibers and spheres.
Microplastics (MPs) are ubiquitous emerging pollutants that have been found in the marine, freshwater, air, and soil environments. Wastewater treatment plants (WWTPs) play an important role in releasing MPs to the environment. Therefore, understanding the occurrence, fate, and removal mechanism of MPs in WWTPs is of great importance towards microplastic control. In this review, the occurrence characteristics and removal rates of MPs in 78 WWTPs from 57 studies were discussed based on Meta-analysis. Specifically, the key aspects regarding MPs removal in WWTPs, such as wastewater treatment processes and MPs shapes, sizes, and polymer compositions were analyzed and compared. The results showed that:① the abundances of MPs in the influent and effluent were 1.56×10-2-3.14×104 n·L-1 and 1.70×10-3-3.09×102 n·L-1, respectively. The abundance of MPs in the sludge ranged from 1.80×10-1 to 9.38×103 n·g-1. ② The total removal rate (>90%) of MPs by WWTPs using oxidation ditch, biofilm, and conventional activated sludge treatment processes was higher than that using sequencing batch activated sludge, anaerobic-anoxic-aerobic, and anoxic-aerobic processes. ③ The removal rate of MPs in primary, secondary, and tertiary treatment process were 62.87%, 55.78%, and 58.45%, respectively. The combination process of "grid+ sedimentation tank+primary sedimentation tank" had the highest removal rate towards MPs in primary treatment processes, and the membrane bioreactor had the highest one beyond other secondary treatment processes. Filtration was the best process in tertiary treatment. ④ The film, foam, and fragment MPs were easier to remove (>90%) than fiber and spherical (<90%) MPs by WWTPs. The MPs with particle size larger than 0.5 mm were easier to remove than those with particle size smaller than 0.5 mm. The removal efficiencies of polyethylene (PE), polyethylene terephthalate (PET), and polypropylene (PP) MPs were higher than 80%.