characterization of the treated effluent and the vermicompost met the quality
requirement for agricultural applications. Hartenstein and Bisesi (1989) carried out
studies on the management of effluents using earthworms with wastewater having
high organic contents resulting to clean effluents and nutrient-rich vermicompost.
2.4 Benefits and Limitations of Vermifiltration
2.4.1 Benefits
Vermifiltration treatment has various advantages over all the conventional biological
wastewater treatment systems—the activated sludge process, trickling filters and
rotating biological contactors in terms of energy usage, cost, ease of operation, etc.
• Vermifiltration process can be carried out with very less capital and operating
costs and also can generate income with the nutrient-rich end product
(vermicompost) and earthworm biomass. Xing et al. (2005) reported 1.16%
nitrogen, 1.22% phosphorus and 1.34% potassium in the earthworm faeces.
• There is no sludge formation in the vermifiltration process which is not possible
in any of the available other wastewater treatment technologies.
• Vermifiltered sewage is free of pathogens as earthworms devour on all the
pathogens (bacteria, fungus, protozoa and nematodes) found in both the wastewater and the sludge as they are their loved food (Pierre et al. 1982).
• Vermifiltration process is odourless, and earthworm plays an important in doing
so as they maintain aerobic conditions in the filter bed by their burrowing actions,
inhibiting the action of anaerobic microorganisms.
• Vermifiltered sewage is free of toxic chemicals as earthworms have the ability to
bioaccumulate high concentrations of toxic chemicals including heavy metals and
also the ‘endocrine disrupting chemicals’ (EDCs) from sewage (Markman et al.
2007; Ireland 1983).
• Different varieties of wastewater can be treated with very less operational and
maintenance cost.
Table 2.3 (continued)
Sr.
no.
Types of
wastewater
Earthworm
species
Organics
removal
(%)
Nutrient
removal
(%)
Bed material and
size
HLR
(m
3
/
m
2
d)
HRT
(h)
10
Synthetic
wastewater
Eisenia
fetida
BOD 70–
81, COD
59–72,
TSS 55–
75
–
Vermicompost,
sand (2–4 mm),
riverbed material,
wood coal, glass
balls, mud balls,
gravel (10–
12.5 mm)
1.5
–
30
M. Khwairakpam
requirement for agricultural applications. Hartenstein and Bisesi (1989) carried out
studies on the management of effluents using earthworms with wastewater having
high organic contents resulting to clean effluents and nutrient-rich vermicompost.
2.4 Benefits and Limitations of Vermifiltration
2.4.1 Benefits
Vermifiltration treatment has various advantages over all the conventional biological
wastewater treatment systems—the activated sludge process, trickling filters and
rotating biological contactors in terms of energy usage, cost, ease of operation, etc.
• Vermifiltration process can be carried out with very less capital and operating
costs and also can generate income with the nutrient-rich end product
(vermicompost) and earthworm biomass. Xing et al. (2005) reported 1.16%
nitrogen, 1.22% phosphorus and 1.34% potassium in the earthworm faeces.
• There is no sludge formation in the vermifiltration process which is not possible
in any of the available other wastewater treatment technologies.
• Vermifiltered sewage is free of pathogens as earthworms devour on all the
pathogens (bacteria, fungus, protozoa and nematodes) found in both the wastewater and the sludge as they are their loved food (Pierre et al. 1982).
• Vermifiltration process is odourless, and earthworm plays an important in doing
so as they maintain aerobic conditions in the filter bed by their burrowing actions,
inhibiting the action of anaerobic microorganisms.
• Vermifiltered sewage is free of toxic chemicals as earthworms have the ability to
bioaccumulate high concentrations of toxic chemicals including heavy metals and
also the ‘endocrine disrupting chemicals’ (EDCs) from sewage (Markman et al.
2007; Ireland 1983).
• Different varieties of wastewater can be treated with very less operational and
maintenance cost.
Table 2.3 (continued)
Sr.
no.
Types of
wastewater
Earthworm
species
Organics
removal
(%)
Nutrient
removal
(%)
Bed material and
size
HLR
(m
3
/
m
2
d)
HRT
(h)
10
Synthetic
wastewater
Eisenia
fetida
BOD 70–
81, COD
59–72,
TSS 55–
75
–
Vermicompost,
sand (2–4 mm),
riverbed material,
wood coal, glass
balls, mud balls,
gravel (10–
12.5 mm)
1.5
–
30
M. Khwairakpam