We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Microplastic Degradation during Wet Air Oxidation Treatment
Summary
This review examines wet air oxidation (WAO) — a process that uses high temperatures and pressures to break down waste — as a potential method for destroying microplastics in wastewater sludge. WAO shows promising results in degrading plastic particles that survive conventional treatment, potentially preventing them from being spread on agricultural land or released into waterways. The authors outline both the advantages of the technology and the challenges that remain before it can be widely deployed. This is a useful addition to the toolkit for managing microplastics that concentrate in sewage sludge.
Microplastic (MP) pollution is one of the main eco-environmental concerns in the early 21st century. Wastewater treatment facilities are known as a critical source of MPs. During wastewater treatment, plastic particles can be enriched into sludge streams, especially in biological-based systems, and be released to soil, natural waters, and marine ecosystems. The wet air oxidation (WAO) process treats aqueous waste streams like wastewater sludge. In WAO, the wastewater is oxidized at high temperatures (120℃–300℃) and pressures (5–200 bar) in an air or oxygen environment. This technology has been recently explored for MP degradation, presenting promising outcomes. This work reviews the literature about WAO technology, focusing on MP removal. MP pollution and related issues are examined, as well as the applicability of WAO technology for treating MP-containing waste streams. The advantages and drawbacks of WAO are outlined, alongside an in-depth discussion of the principles and mechanisms involved in MP degradation through WAO processes. Last, the study identifies opportunities for further advancement in this research field.
Sign in to start a discussion.
More Papers Like This
Simultaneous degradation of microplastics and sludge during wet air oxidation
This study showed that wet air oxidation (WAO) — a high-temperature, high-pressure sludge treatment — can simultaneously break down polyethylene, polystyrene, and PET microplastics along with the sewage sludge they contaminate. All three plastic types were degraded without leaving detectable solid plastic residues, with acetic acid as the primary breakdown product. This is significant because conventional wastewater treatment cannot destroy microplastics, so WAO represents a promising upgrade for eliminating a major environmental release pathway.
Ozone-mediated breakdown of microplastics in aqueous environments
Researchers examined how ozone-based advanced oxidation processes break down microplastics in water treatment settings. They found that while ozone can degrade certain plastics, the effectiveness varies depending on particle size, polymer type, and treatment conditions, and the process may generate nanoplastic byproducts. The study highlights both the promise and limitations of ozone treatment as a strategy for removing microplastics from wastewater.
Fate, characteristics, and potential threat of microplastics in sludge under various dewatering treatments
Researchers compared four different sludge dewatering treatments used at wastewater plants and examined how each process affected the microplastics trapped in the sludge. They found that advanced oxidation treatments altered the surface properties of the microplastics and increased their ability to absorb heavy metals. The findings raise concerns that certain sludge treatment methods could make microplastics more environmentally hazardous when the treated sludge is disposed of or reused.
Fate of microplastics during conventional and hydrothermal treatments of sewage sludge: a short review
This review examines the fate of microplastics during conventional and hydrothermal treatment of sewage sludge, noting that approximately 90% of microplastics entering wastewater treatment plants are retained in sludge. Researchers found that while conventional disposal routes concentrate microplastics in sludge destined for land application, hydrothermal treatments offer potential pathways to degrade or transform microplastics, though the efficiency and byproducts of these processes require further investigation.
Microplastic degradation methods and corresponding degradation mechanism: Research status and future perspectives
This review summarizes current methods for degrading microplastics, including advanced oxidation processes, biodegradation, and thermal treatments, along with their underlying mechanisms. The study highlights that while several approaches show promise in laboratory settings, challenges remain in scaling these technologies for real-world environmental remediation of microplastic pollution.