Abstract
Microplastics (MPs) are widespread in sewer systems, but how different MPs affect methane emissions from sewer systems remains unclear. Three typical MPs, non-biodegradable MPs (polypropylene (PP) and polyamide (PA)), and biodegradable MPs (polylactic acid (PLA)), were added to the sewer sediments at different concen-trations (7 and 20 particles/gww TS) and incubated for 70 days. The effects of PP and PA on methane production were concentration-dependent: the addition of PP increased methane production by 16.90%-20.40%, while the addition of PA decreased it by 9.11%-54.67%. By contrast, 20 particles/gww PLA produced the most significant increase in methane relative to the control. MPs promote the decomposition of 15%-50% of organic matter in sewage sludge. Simultaneously, the change in enzyme activity depends on the properties of the MPs. Microbial community analysis indicates that MPs reduce microbial diversity, with variations observed. These findings reveal the effect of MPs on methane emissions in sewers and the mechanisms by which MPs modulate the "organic matter-reactive oxygen species-enzyme activity-microorganisms" pathway to affect methanogenesis. The study provides valuable insights into the environmental impact of MPs in sewer systems and their effect on methane production.
NETL
NSTL
Elsevier