Bioresource Technology 90 (2003) 169–173

Municipal solid waste management through vermicomposting

employing exotic and local species of earthworms
Kaviraj a, Satyawati Sharma b,*

a
School of Energy and Environmental Studies, DAVV, Indore (M.P.) 452017, India
b
Centre for Rural Development and Technology, Indian Institute of Technology, New Delhi 110016, India
Received 10 March 2003; received in revised form 22 March 2003; accepted 26 March 2003

Abstract
A comparative study was conducted between exotic and local (epigeic-Eisenia fetida and anaecic-Lempito mauritii, respectively)
species of earthworms for the evaluation of their efficacy in vermicomposting of municipal solid waste (MSW). Vermicomposting of
MSW for 42 days resulted in significant difference between the two species in their performance measured as loss in total organic
carbon, carbon–nitrogen ratio (C:N) and increase in total Kjeldahl nitrogen, electrical conductivity and total potassium and weight
loss of MSW. The change in pH and increase in number of earthworms and cocoons and weight of earthworms were non-signi-
ficant.
Ó 2003 Elsevier Ltd. All rights reserved.

Keywords: MSW; Eisenia fetida; Lempito mauritii; Vermicomposting

1. Introduction control over the key areas of temperature, moisture and

aerobicity (Price, 1988). An improved mechanical sepa-
A rapidly increasing population and high rate of in- rator, having a novel combing action, for removing live
dustrialization has increased the problem of solid waste earthworms from vermicomposts has also been intro-
management. The problem has further increased in cities duced by Price and Phillips (1990).
because of shortage of dumping sites and strict envi- The action of earthworms in the process of vermi-
ronmental legislation, so scientists are seeking for composting of waste is physical and biochemical. The
management alternatives, which should be ecofriendly, physical process includes substrate aeration, mixing as
cheap and fast. Municipal solid waste (MSW) is highly well as actual grinding while the biochemical process is
organic in nature, so vermicomposting has become an influenced by microbial decomposition of substrate in
appropriate alternative for the safe, hygienic and cost the intestine of earthworms (Hand et al., 1998). Various
effective disposal of it. Earthworms feed on the organics studies have shown that vermicomposting of organic
and convert material into casting (ejected matter) rich in waste accelerates organic matter stabilization (Neuha-
plant nutrients. The chemical analyses of casts show two user et al., 1998; Frederickson et al., 1997) and gives
times available magnesium, 15 times available nitrogen chelating and phytohormonal elements (Tomati et al.,
and seven times available potassium compared to the 1995) which have a high content of microbial matter and
surrounding soil (Bridgens, 1981). A number of refer- stabilised humic substances.
ences are available on the potential of earthworms in In India the exotic epigeic species, like Eudrilus
vermicomposting of solid waste particularly household euginae (Ashok, 1994), Parionyx excavatus (Kale et al.,
waste (Appelholf et al., 1998). Advanced systems for 1982) and Eisenia fetida (Hartenstein et al., 1979) are
vermicomposting are based on top feeding and bottom being used for vermicomposting. The hazards of using
discharge of a raised reactor thus providing stability and alien species are well known. History is littered with
examples of confrontations between indigenous and
foreign organisms (Mackenzie, 1991). The introduction
*
Corresponding author. Tel.: +91-659-1716; fax: +91-686-2037. of foreign species has been justified by a few scientists
E-mail address: ddf@admin.iitd.ernet.in (S. Sharma). (Lavelle et al., 1989; Murphy, 1993), though it is

0960-8524/$ - see front matter Ó 2003 Elsevier Ltd. All rights reserved.
doi:10.1016/S0960-8524(03)00123-8
170 Kaviraj, S. Sharma / Bioresource Technology 90 (2003) 169–173

extremely unnecessary and undesirable to tamper with 2.5. Species observation

local biodiversity (Ismail, 1995). Keeping this in view
E. fetida and Lempito mauritii (exotic and local species The increase in growth rate, number of earthworms
respectively) were chosen for the comparative study of and cocoons and weight of earthworms were observed
their potential in vermicomposting of MSW. weekly. The mean of three replicates was used to express
the results.

2.6. Statistical analysis

2. Methods
All the reported data are the means of three repli-
2.1. Collection and culturing of earthworms cates. Two way analysis of variance (ANOVA) was done
to determine any significant difference among the pa-
The earthworms E. fetida were obtained from an rameters analysed in vermicompost. ‘‘StudentÕs t-distri-
earthworm bank (pit) in Micromodel, IIT Delhi where it bution’’ was done to determine any significant difference
has been cultured for the last 4 years (initially the species between the numbers and weights of earthworms (E.
was collected from G.H.V.K. University, Banglore). The fetida and L. mauritii) used.
species L. mauritii was collected from the soil of Mi-
cromodel, IIT Delhi and was identified by Prof. Julka,
National Zoological Survey of India, Solan, India. 3. Results and discussion

2.2. Collection of MSW Table 1 summarizes data pertaining to TOC, TKN,

and C:N ratio. The initial TOC, TKN and C:N ratio of
The organic waste used as substrate (MSW), was MSW were 17.6%, 0.31% and 56.7%. Data revealed a
collected from the waste collection site, IIT Delhi where significant difference in percentage decrease of the TOC
organic waste was being separated out manually. The in all three treatments (L. mauritii, E. fetida and con-
waste was predecomposed for eight days prior to study. trol). The maximum carbon reduction, after 42 days,
was obtained with E. fetida (44.3%) followed by L.
mauritii (44.1) and control (17.3). Our data are sup-
2.3. Experimental setup
ported by Elvira et al. (1998) who observed 20–42% loss
of carbon as CO2 during vermicomposting of paper mill
The experiments were conducted in earthenpots, each
and dairy sludges.
of capacity 2 kg waste, with a small hole at the bottom.
Total nitrogen content increased as a result of carbon
A total of 54 earthen pots were used and kept in three
loss with significant differences between the treatments
sets of 18 pots for E. fetida, L. mauritii and control
(Table 1(Panel A)). The loss of dry mass (organic car-
(without any earthworms). One kilogram of waste was
bon) in terms of CO2 as well as water loss by evapora-
taken in each pot along with 200 g of cowdung and soil
tion during mineralization of organic matter (Viel
(100 g cowdung and 100 g soil) to provide an initial
et al., 1987) might have determined the relative increase
favorable environmental condition for the worms.
in nitrogen. However in general the final content of
Twenty healthy earthworms of the same size (E. fetida
nitrogen in vermicomposting is dependent on initial
and L. mauritii) were introduced in each of two sets of
nitrogen present in the waste and the extant of decom-
earthen pots. Moisture content was maintained between
position (Crawford, 1983; Gaur and Singh, 1995). De-
40% and 60% during the study. The duration of experi-
crease in pH may be an important factor in nitrogen
ments was six weeks.
retention as this element is lost as volatile ammonia at
high pH values (Hartenstein and Hartenstein, 1981).
2.4. Chemical analysis Table 2 summarizes the data related to K and EC. A
10% increase was observed in TK by E. fetida and 5%
The chemical analysis of raw organic waste used and increase by L. mauritii (control did not show any TK
vermicompost samples, collected weekly, was done for increase). The TK difference between treatments was
total organic carbon (TOC), total Kjeldahl nitrogen significant while it was found to be non-significant rel-
(TKN) and total potassium (TK), electrical conductivity ative to the duration (Table 2(Panel A)). The E. fetida
(EC) and pH. The TKN and TOC were estimated by was superior to L. mauritii in this regard. The microflora
micro-Kjeldahl (Singh and Pradhan, 1981) and Walkey also influences the level of available potassium. Acid
and BlackÕs Rapid Titration methods (1934), respec- production by the micro-organisms is the major mech-
tively. TK was estimated by Flame Emission Technique anism for solubilizing of insoluble potassium. The im-
while EC and pH were determined using conductivity portant acids in phosphorus solubilisation are carbonic,
meter and pH meter. nitric, and sulfuric. The enhanced number of microflora
 Kaviraj, S. Sharma / Bioresource Technology 90 (2003) 169–173 171

present in the gut of earthworms in the case of vermi-

composting might have played an important role in this

C:N

4.92
8.23
–
process and increased K2 O over the control.
All the treatments showed a similar pattern of
change in EC, which increased from the initial value of

TKN

11.0
1.60–1.86 ms/cm in the case of E. fetida, 1.73 in

9.0

–
L. mauritii and 1.64 ms/cm in control after the whole
Chemical analysis of compost produced with different treatments for TOC, TKN and C:N ratio (Panel A), ANOVA of days and treatments for TOC and TKN (Panel B)

F -value
period of decomposition. A gradual increase in EC

TOC

4.49
7.44
was observed with increase in decomposition time.

–
These results are corroborated by Wong et al. (1997).
The increase in EC might have been due to the loss of
56.7
0.02
56.7
0.06
56.7
0.09
56.4
0.13
56.4
0.12
54.3
0.11
54.0
0.16

weight of organic matter and release of different mineral

salts in available forms (such as phosphate, ammonium,
C:N

C:N

38.0
187
313
potassium).
The results related to the weight loss and pH are
depicted in Table 3. There was a decrease in total bulk
0.31
0.10
0.31
0.05
0.31
0.06
0.31
0.08
0.31
0.12
0.32
0.13
0.32
0.10

weight of the substrates with the passage of time. On

0.0009
0.0011
0.0001
TKN

TKN

analysing the result by ANOVA, the decrease in weight

of substrate varied significantly between the treatments
and days. The pH decline in all the cases was believed to
17.6
0.11
17.6
0.07
17.6
0.08
17.5
0.07
17.5
0.09
17.4
0.05
17.3
0.09

occur because of the high mineralization of the nitrogen

Control

and phosphorus into nitrates/nitrites and orthophos-

TOC

TOC

11.6
19.2
2.58
MS

phate.
Interesting results were obtained pertaining to the
growth of earthworms. Although the doubling rate in
56.7
0.11
56.1
0.13
52.6
0.16
47.2
0.09
41.0
0.12
33.7
0.15
28.1
0.03

terms of number was greater in the case of E. fetida (51)

than in L. mauritii (46), the latter gained more weight
C:N

C:N

12
6
2

(0.39 g/earthworm) than did E. fetida (0.20 g/earth-

worm) in 42 days (Table 4). Ismail (1995), who got
All values are the mean of three replicates; all values are given in percentage except C:N ratio.
0.31
0.01
0.31
0.01
0.32
0.03
0.33
0.04
0.35
0.02
0.35
0.05
0.36
0.01

double numbers of L. mauritii in 38.0 days, supports our

data. When the results were analyzed by t-test the dif-
TKN

TKN

ferences between these two species were found to be

12
6
2

non-significant. The increase in population might also

be attributed to the C:N ratio decreasing with time
17.6
0.10
17.4
0.08
16.8
0.09
15.6
0.02
11.8
0.01
11.8
0.01
10.2
0.13

(Nedgwa and Thompson, 2000).

Local
TOC

TOC
DF

12
6
2

4. Conclusion
56.7
0.05
54.0
0.08
51.2
0.12
46.0
0.14
40.0
0.11
32.5
0.09
25.1
0.12

1123
625
457
C:N

C:N

On the basis of chemical analysis, the observations

indicated the E. fetida to be superior in performance
over L. mauritii, in terms of loss of TOC, reduction in
0.31
0.12
0.31
0.06
0.32
0.09
0.33
0.11
0.34
0.08
0.36
0.06
0.39
0.04

carbon to nitrogen ratio, increase in EC and TK.

0.0055
0.0022
0.0022

Though the epigeic species of earthworms (i.e. E. fetida)

TKN

TKN

are capable of working hard to convert all the organic

waste into manure, they are of no significant value in
modifying the structure of soil. The anaecic (like L.
17.6
0.14
17.2
0.16
16.4
0.13
15.2
0.16
13.6
0.17
11.7
0.05
9.8
0.12

mauritii) however, are capable of both organic waste

Exotic
TOC

TOC

consumption as well as of modifying the soil structure.

69.8
38.4
31.0
SS

Moreover L. mauritii can also be used for other pur-

poses i.e. medicinal (Reynolds and Reynolds, 1972; Hori
Treatments

et al., 1974), as a rich source of protein (Hennuy and

Residual
Panel A

Panel B

Gaspar, 1986) or pig feed (Hardwood and Sabine, 1978;

Table 1

Days

Days

Makarda et al., 1979) and in nematode control (Dash

14
21
28
35
42
0
7

et al., 1980; Yeates, 1981) besides vermicomposting.

172 Kaviraj, S. Sharma / Bioresource Technology 90 (2003) 169–173

Table 2
Chemical analysis of compost produced with different treatments for EC and TK (Panel A), ANOVA of days and species for TK and EC (Panel B)
Days Exotic Local Control
EC TK EC TK EC TK
Panel A
0 1.60
0.05 0.20
0.02 1.60
0.06 0.20
0.09 1.60
0.03 0.20
0.01
7 1.60
0.06 0.20
0.03 1.60
0.08 0.20
0.02 1.60
0.02 0.20
0.05
14 1.61
0.08 0.20
0.01 1.61
0.07 0.20
0.03 1.60
0.01 0.20
0.03
21 1.61
0.03 0.20
0.09 1.61
0.02 0.21
0.01 1.62
0.08 0.20
0.04
28 1.72
0.09 0.21
0.05 1.67
0.03 0.21
0.05 1.62
0.02 0.20
0.03
35 1.79
0.07 0.22
0.03 1.72
0.01 0.21
0.06 1.64
0.03 0.20
0.02
42 1.86
0.02 0.22
0.02 1.73
0.01 0.21
0.02 1.64
0.05 0.20
0.01

SS DF MSS F -value
TK EC TK EC TK EC TK EC
Panel B
Days 0.0004 0.0157 6 6 0.00006 0.0026 3.0 8.72
Treatments 0.0003 0.0625 2 2 0.00015 0.0312 7.5 17.33
Residual 0.0003 0.0227 12 12 0.00002 0.0018 – –
All values are the mean of three replicates; all values of K are given in the percentage and EC in ms/cm.

Table 3
Chemical analysis of compost produced with different treatments for weight loss and pH (Panel A), ANOVA of days and treatments for weight loss
and pH (Panel B)
Days Exotic Local Control
Wt. loss pH Wt. loss pH Wt. loss pH
Panel A
0 0
0.00 8.9
0.09 0
0.00 8.9
0.09 0
0.00 8.9
0.02
7 3.3
0.01 8.4
0.12 3.3
0.09 8.4
0.12 2.3
0.08 8.4
0.03
14 6.6
0.02 7.4
0.12 5.5
0.08 7.0
0.13 3.6
0.06 7.2
0.01
21 9.4
0.03 6.9
0.11 5.5
0.06 7.0
0.09 3.6
0.02 7.2
0.01
28 13.5
0.02 7.1
0.09 16.8
0.02 7.2
0.08 8.0
0.06 6.7
0.02
35 20.0
0.12 6.9
0.01 16.8
0.16 7.2
0.09 8.0
0.02 6.7
0.06
42 39.3
0.12 6.9
0.02 30.71
0.10 7.1
0.02 9.4
0.03 6.7
0.03

SS DF MSS F -value
Wt. loss pH Wt. loss pH Wt. loss pH Wt. loss pH
Panel B
Days 1422.3 5.10 6 6 237 8.50 8.34 0.25
Treatments 257.8 5.85 2 2 128.9 2.92 4.53 0.86
Residual 341.8 40.39 12 12 28.4 3.36 – –
All values are the mean of three replicates; the value of weight loss is given in percentage.

Table 4
Change in growth rate, number of earthworms and cocoons and weight of earthworms
Days Exotic Local
NW GR NC Wt. NW GR NC Wt.
0 20.0 0.0 0.00 4.0 20.0 0.0 0.00 6.0
7 20.0 0.0 0.10 4.1 20.0 0.0 0.05 6.2
14 20.0 2.0 0.26 4.2 21.0 3.0 0.13 6.2
21 21.0 4.5 0.80 4.4 22.0 6.5 0.75 6.6
28 22.0 8.5 1.60 5.2 22.0 7.5 1.60 7.6
35 37.0 85.5 9.60 11.6 29.0 46.5 6.60 13.6
42 51.0 156.5 14.0 12.0 46.0 130.0 8.60 18.6
NW––mean number of earthworms; GR––growth rate of earthworms (number) in percentage; NC––mean number of cocoons; Wt.––mean weight of
earthworms (gm); t-calculated: earthwormsÕ number ¼ 0.20, earthwormsÕ weight ¼ 0.96.
 Kaviraj, S. Sharma / Bioresource Technology 90 (2003) 169–173 173

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