The AD assays were conducted in 2-L (working volume)
laboratory-scale batch reactors. Temperatures were maintained at a
mesophilic (37 1 C) range by means of incubators. Test specimens
(25 g of sample carbon) were mixed with 750 g wet of
methanogenically active sludge obtained in October of 2010 from a
full-scale (3000 m3) anaerobic digester located at the City of Akron
wastewater treatment plant and operated by KB Compost Services,
Akron, Ohio [28]. This was mixed with 187.5 g wet of the organic
fraction of municipal solid waste (OFMSW) of the Medina County,
Ohio Solid Waste District to achieve the desired solids content for
the test and to provide supplemental nutrients for the anaerobic
microbial consortia. The chemical properties of the seed sludge and
OFMSW substrate are shown in Table 4. Ammonium phosphate
(Fisher Scientific, PA, U.S.) was added to the mixture to adjust the
C:N ratio to a value of 20:1 considering the carbon content of the
test specimen.