effluents. However, very few studies (Table 1.1) are being carried out on the
vermifiltration of industrial wastewater because of the sensitive nature of earthworms towards parameters like pH, heavy metals, pesticides and salinity. Regardless
of this, vermifiltration applied to industrial effluent from the food and beverage
sector has shown encouraging pollutant removal efficiency and can pave way for
application for many other industrial effluents that have low or no toxicity (Singh
et al. 2019a). Additionally, vermifiltration system has been applied to other industrial effluents, such as petroleum industry and pharmaceutical industry (Dhadse et al.
2010; Sinha et al. 2012). Sinha et al. (2007) have successfully applied vermiltration
system to treat effluent from dairy industries which mainly consist of organics like
proteins, carbohydrates and fats. According to the study, earthworm species Eisenia
fetida has resulted in the removal of about 99% BOD 5 and COD in the range of
80–90%. It also leads to the removal of TDS and TSS in the range of 90–92% and
90–95%, respectively. Another study conducted by Sinha et al. (2012) on petroleum
industry wastewater has shown 99% removal of C10–C14, C15–C28 and C26–C36.
Further, cheese whey waste has been treated by using vermifiltration and achieved
about 76% BOD, 82% COD and 77% TSS removal efficiency (Merlin and Cottin
2009). Ghatnekar et al. (2010) reported the removal of COD and BOD by 89 and
90%, respectively, from gelatine industry wastewater employing earthworm species
Lumbricus rubellus. Dhadse et al. (2010) studied application of vermifiltration on
herbal pharmaceutical effluents using earthworm Eudrilus eugeniae at different
organic loading rates (OLR) of 0.8, 1.6, 2.4 and 3.2 kg COD/m
3 /d with 3.2 kg
COD/m
3 /d as the optimum with COD and BOD removal efficiencies in the range of
85–94% and 90–96%, respectively. Macrophyte-assisted vermifiltration was applied
to treat synthetic dairy wastewater by employing macrophyte species Canna indica
and reported removal of BOD, COD, TSS, TDS and TN by 81%, 76%, 85%, 23%
and 43%, respectively (Samal et al. 2017b).
1.4 Mechanisms of Vermifiltration Technique
Vermifiltration technique works in combination of earthworms and microbes. Evolving from the basic system, macrophyte-assisted vermifiltration has emerged as an
eco-friendly alternative for wastewater treatment and recycling. In order to unravel
the treatment mechanisms, the roles of various layers and components of a typical
macrophyte-assisted vermifiltration system have been schematically presented in
Fig. 1.5. The solids retained on the filter bed are consumed by the earthworms and
converted into the humus (Sinha et al. 2008; Singh et al. 2017). A microbial layer
formed on the filter bed also contributes to the degradation of the contaminants
retained on the filter bed. Generally, vermifiltration system consists of components,
i.e. earthworms and filter bed. Filter bed supports the earthworm growth by providing food source by sorption mechanism from the wastewater, and a microbial layer is
formed because of low porosity (Liu et al. 2013; Singh et al. 2017; Wang et al.
2010a, b). Further, the earthworm active zone is also known as aerobic zone while
12
Bhavini et al.
vermifiltration of industrial wastewater because of the sensitive nature of earthworms towards parameters like pH, heavy metals, pesticides and salinity. Regardless
of this, vermifiltration applied to industrial effluent from the food and beverage
sector has shown encouraging pollutant removal efficiency and can pave way for
application for many other industrial effluents that have low or no toxicity (Singh
et al. 2019a). Additionally, vermifiltration system has been applied to other industrial effluents, such as petroleum industry and pharmaceutical industry (Dhadse et al.
2010; Sinha et al. 2012). Sinha et al. (2007) have successfully applied vermiltration
system to treat effluent from dairy industries which mainly consist of organics like
proteins, carbohydrates and fats. According to the study, earthworm species Eisenia
fetida has resulted in the removal of about 99% BOD 5 and COD in the range of
80–90%. It also leads to the removal of TDS and TSS in the range of 90–92% and
90–95%, respectively. Another study conducted by Sinha et al. (2012) on petroleum
industry wastewater has shown 99% removal of C10–C14, C15–C28 and C26–C36.
Further, cheese whey waste has been treated by using vermifiltration and achieved
about 76% BOD, 82% COD and 77% TSS removal efficiency (Merlin and Cottin
2009). Ghatnekar et al. (2010) reported the removal of COD and BOD by 89 and
90%, respectively, from gelatine industry wastewater employing earthworm species
Lumbricus rubellus. Dhadse et al. (2010) studied application of vermifiltration on
herbal pharmaceutical effluents using earthworm Eudrilus eugeniae at different
organic loading rates (OLR) of 0.8, 1.6, 2.4 and 3.2 kg COD/m
3 /d with 3.2 kg
COD/m
3 /d as the optimum with COD and BOD removal efficiencies in the range of
85–94% and 90–96%, respectively. Macrophyte-assisted vermifiltration was applied
to treat synthetic dairy wastewater by employing macrophyte species Canna indica
and reported removal of BOD, COD, TSS, TDS and TN by 81%, 76%, 85%, 23%
and 43%, respectively (Samal et al. 2017b).
1.4 Mechanisms of Vermifiltration Technique
Vermifiltration technique works in combination of earthworms and microbes. Evolving from the basic system, macrophyte-assisted vermifiltration has emerged as an
eco-friendly alternative for wastewater treatment and recycling. In order to unravel
the treatment mechanisms, the roles of various layers and components of a typical
macrophyte-assisted vermifiltration system have been schematically presented in
Fig. 1.5. The solids retained on the filter bed are consumed by the earthworms and
converted into the humus (Sinha et al. 2008; Singh et al. 2017). A microbial layer
formed on the filter bed also contributes to the degradation of the contaminants
retained on the filter bed. Generally, vermifiltration system consists of components,
i.e. earthworms and filter bed. Filter bed supports the earthworm growth by providing food source by sorption mechanism from the wastewater, and a microbial layer is
formed because of low porosity (Liu et al. 2013; Singh et al. 2017; Wang et al.
2010a, b). Further, the earthworm active zone is also known as aerobic zone while
12
Bhavini et al.