molecular structure binds with different metal ions and thereby helps in metal
removal (Singh et al. 2017).
In addition, significant pathogen reduction by the vermifiltration technique has
been reported (Samal et al. 2017a). Earthworms have the capacity to cull the
pathogens present in the ingested materials (Sinha et al. 2010). The pathogen
reduction in vermifiltration is caused mainly because of the enzymatic and microbial
activities (Alberts et al. 2002; Hartenstein 1978; Monroy et al. 2008, 2009; Swati and
Hait 2018). In addition, inhibition in humates in the guts of earthworms is responsible for the pathogen removal (Brown and Mitchell 1981; Hartenstein 1978).
1.5 Future Perspectives
The potential of vermifiltration to treat domestic as well as industrial wastewater is
well documented. An insight of vermifiltration based on the experimental results,
design configurations and treatment mechanism has been provided. Vermifiltration
integrated with macrophyte is an emerging technique for the wastewater treatment.
Most of the studies have demonstrated vertical vermifilter at laboratory-scale level
only for synthetic wastewater treatment. For this purpose, vermifiltration studies
with real sewage and industrial effluents will be useful to assess the organic, nutrient
and pathogen removal efficiency. However, research is warranted to explore the
different vermifiltration system design configuration for wastewater treatment. Various process parameters such as earthworm stocking density, flow rate, hydraulic
retention time (HRT), OLR and filter bed configuration need to be optimized for
scaling-up the process. In addition, most of the studies have employed epigeic
earthworm species Eisenia fetida only. In this context, it is pertinent to explore the
various other earthworm species as pure and mixed cultures as diverse earthworm
species co-exist in nature. Studies are required to be conducted to explore the effect
of symbiotic relationships or mixed earthworm species on the removal of contaminants from wastewater.
1.6 Conclusions
The applicability of vermifiltration technique for the treatment of both sewage and
industrial effluents along with the treatment mechanisms involved has been extensively discussed. Additionally, the potential of macrophytes has also been discussed
in an integrated vermifiltration system for wastewater treatment. Further, the influence of different filter design and operational parameters on the system performance
has been presented. The combined effect of earthworm active zone and filter media
in the vermifiltration system has been reported for the effective removal of pollutants
from the wastewater. Maximum organic and nutrient removal efficiencies of 99%
BOD, 96% COD, 86% nitrogen and 83% phosphorus have been reported in the
vermifiltration of wastewater. Pathogen removal of 90–99% for FC and 99% for TC,
14
Bhavini et al.
removal (Singh et al. 2017).
In addition, significant pathogen reduction by the vermifiltration technique has
been reported (Samal et al. 2017a). Earthworms have the capacity to cull the
pathogens present in the ingested materials (Sinha et al. 2010). The pathogen
reduction in vermifiltration is caused mainly because of the enzymatic and microbial
activities (Alberts et al. 2002; Hartenstein 1978; Monroy et al. 2008, 2009; Swati and
Hait 2018). In addition, inhibition in humates in the guts of earthworms is responsible for the pathogen removal (Brown and Mitchell 1981; Hartenstein 1978).
1.5 Future Perspectives
The potential of vermifiltration to treat domestic as well as industrial wastewater is
well documented. An insight of vermifiltration based on the experimental results,
design configurations and treatment mechanism has been provided. Vermifiltration
integrated with macrophyte is an emerging technique for the wastewater treatment.
Most of the studies have demonstrated vertical vermifilter at laboratory-scale level
only for synthetic wastewater treatment. For this purpose, vermifiltration studies
with real sewage and industrial effluents will be useful to assess the organic, nutrient
and pathogen removal efficiency. However, research is warranted to explore the
different vermifiltration system design configuration for wastewater treatment. Various process parameters such as earthworm stocking density, flow rate, hydraulic
retention time (HRT), OLR and filter bed configuration need to be optimized for
scaling-up the process. In addition, most of the studies have employed epigeic
earthworm species Eisenia fetida only. In this context, it is pertinent to explore the
various other earthworm species as pure and mixed cultures as diverse earthworm
species co-exist in nature. Studies are required to be conducted to explore the effect
of symbiotic relationships or mixed earthworm species on the removal of contaminants from wastewater.
1.6 Conclusions
The applicability of vermifiltration technique for the treatment of both sewage and
industrial effluents along with the treatment mechanisms involved has been extensively discussed. Additionally, the potential of macrophytes has also been discussed
in an integrated vermifiltration system for wastewater treatment. Further, the influence of different filter design and operational parameters on the system performance
has been presented. The combined effect of earthworm active zone and filter media
in the vermifiltration system has been reported for the effective removal of pollutants
from the wastewater. Maximum organic and nutrient removal efficiencies of 99%
BOD, 96% COD, 86% nitrogen and 83% phosphorus have been reported in the
vermifiltration of wastewater. Pathogen removal of 90–99% for FC and 99% for TC,
14
Bhavini et al.