Effects of combined composting and vermicomposting of waste sludge on arsenic fate and bioavailability

- Industrial sludge with high As content was treated by composting and vermicomposting.
- The volume of compost decreased, which led to an increase in total As content.
- The labile arsenic fraction was significantly decreased.
- AsV was the predominant arsenic species formed.
- The mobile fraction was not directly related to bioavailability to earthworms.