process that adapts traditional vermicomposting system into a passive
wastewater treatment process by using potentials of epigeic
earthworms. According to Komarowski [23] in vermi-biofiltration
system suspended solids are trapped on top of the vermifilter and
processed by the earthworms and fed to the soil microbes immobilized
in the vermifilter. The dissolved and suspended organic and inorganic
solids are trapped by adsorption and stabilization through
complex biodegradation processes that take place in the “living soil”
inhabited by earthworm and the aerobic microbes. Intensification of
soil processes and aeration by earthworms enable the soil stabilization
and filtration system become effective and smaller in size [19].
In general, inoculated earthworms in vermibeds accumulate many organic
pollutants fromthe surrounding soil environment, passive absorption
through the bodywall and also intestinal uptake during the passage
of soil through the gut [24]. The efficacy of vermi-biofiltration system is
already described in literature (Table 1). Sinha and his group investigated
the potential of vermi-biofiltration system in treatment of dairy industry
effluent [3]. They claimed that earthworms have been found to remove
the 5 day BOD by over 98%, COD by 80–90%, TDS by 90–92% from any
liquid wastes by the general mechanism of ingestion and biodegradation
of organic wastes. According to a study conducted by Ghatnekar
et al. [18] suggested that the vermi-biofiltration systemis efficient to remove
COD and BOD load of wastewater generated from gelatin industry.
They applied a three-tier biotechnology unit coupled with vermibiofiltration
systemto convert secondary liquid effluents froma gelatin
manufacturing unit into bio-safe clean water. Results thus, suggested a
significant decrease in COD by 90% and BOD by 89%. Recently, Zhao et al.
[2] studied the stabilization of domestic waste water sludge using
earthworms and results have revealed that the presence of earthworms
in the vermibeds to the significant stabilization of the sludge. The volatile
suspended solids (VSS) reduction in the vermibeds was in the
ranges of 56.2–66.6% in different treatment units aided with earthworms.
Similarly, Sinha et al. [19] developed a low-cost sustainable