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Microbial activity during composting of anthracene-contaminated soil
1Department of Biology, Institute for Natural Resources and Environmental Management, Hong Kong Baptist University, Kowloon Tong, Hong Kong.
Chemosphere
|July 18, 2003
Summary
Adding old compost to kitchen waste during composting increased thermophilic microbes but did not significantly enhance anthracene removal. Microbial communities shifted, with diversity peaking at lower temperatures.
Area of Science:
- Environmental Microbiology
- Bioremediation
- Composting Science
Background:
- Soil contamination with polycyclic aromatic hydrocarbons (PAHs) like anthracene poses environmental risks.
- Composting is a viable method for PAH degradation, but efficiency can be limited.
- The role of microbial succession and enzyme activity in anthracene removal during composting requires further investigation.
Purpose of the Study:
- To investigate microbial activity and anthracene removal during laboratory composting of anthracene-spiked soil mixed with kitchen waste.
- To evaluate the impact of inoculating with old compost, containing acclimated microorganisms, on composting efficiency.
- To analyze microbial succession, enzyme activity, microbial diversity, and anthracene removal rates over 42 days.
Main Methods:
- Laboratory-scale in-vessel composting of soil and kitchen waste mixture.
- Addition of old compost as inoculum to assess its effect.
- Monitoring of microbial parameters: succession, enzyme activity (polyphenol oxidase, catalase), and diversity.
- Quantification of anthracene removal rate throughout the 42-day composting period.
Main Results:
- Inoculation with old compost increased thermophilic microorganism populations but did not significantly improve anthracene removal rates.
- A clear microbial succession was observed, progressing from mesophilic bacteria to thermophilic bacteria and actinomycetes.
- Polyphenol oxidase activity decreased, while catalase activity showed irregular variations during composting.
- Microbial diversity increased significantly with temperature rise from 35°C to 56°C, then declined at sustained high temperatures (56-59°C).
Conclusions:
- While old compost inoculation supports thermophilic microbial growth, it offers limited enhancement for anthracene biodegradation in this composting system.
- Microbial community dynamics, including succession and diversity shifts, are strongly influenced by composting temperature.
- Understanding these microbial responses is crucial for optimizing composting processes for effective bioremediation of contaminated soils.