Arsenic remediation using
anaerobically digested sewage sludge
Anaerobically digested sewage sludge, which is a mixed culture, was used as
the inoculum for the volitilization of inorganic arsenic. The sludge was
initially activated by feeding with a nutrient solution containing molasses.
Activity of the culture was monitored by measuring the gas production from
the digester. Inorganic arsenic at different concentrations was spiked into
the bioreactor and its effect on gas production was monitored. It was found
that arsenic was distributed in solid, liquid and gaseous forms. The results
indicated that arsenic concentration up to 34 ppm was not toxic to the
microorganisms. The present study confirms that microorganisms in
anaerobically digested sewage sludge volatilizes inorganic arsenic.