Palygorskite changes heavy metal bioavailability and microbial functional diversity in sewage sludge composting

The chemical speciation analysis by a Community Bureau of Reference-sequential extraction indicated the contribution of palygorskite to reduce the bioavailability of a model metal, Cu, during the composting process.

The Biolog EcoPlate TM test revealed that the microbial community showed better capability of utilizing complex macro-molecules (such as miscellaneous and polymers) in the presence of palygorskite. Increasing the palygorskite contents from 1% to 5%, the microbial activity showed an increasing tendency. However, continuously increasing the palygorskite resulted in a decline of the microbial metabolism.