Chapter - I

INTRODUCTION

ORGANIC WASTE AND ORGANIC WASTE MANAGEMENT

As the human civilization grew year by year, the production of organic

solid wastes increased by quantity as well as by variety The action of

microorganisms and others present in t he surroundings, digested and

converted the biodegradable wastes into harmless useful nutrient products

The recycling of organic waste into organic manure helps in the maintenance

of healthy soil by Improving soil quality thereby increasing crop production

and ultimately the welfare of man kind (Gaur and Singh. 1995) Among the

bioconversion methods composting and vermicomposting are the two non-

polluting methods in the recycling of organic s o l ~ d wastes The conversion of

organic waste Into manure by compost and vermlcompost, partly solves the

organic waste d~sposa l problems for municipal~ties, for agro ~ndustries and

for the ~ndus t r i a l corporations However demons t r a t~on o f the recycling

process 1s e s s e n t ~ a l a t t he laboratory level specifically t o identify t h e

extent of practical utility and advantages

GENERAL INTRODUCTION TO BIOLOGICAL METHODS OF ORGANIC WASTE

RECYCLING

The organic solid wastes are often rich in plant nutrients and energy

content When these wastes are not properly handled or disposed, they cause

pollution / contamination leading to pathological condi t~ons But if utilized

properly they can be turned into products of high economic value A possible

method envisaged for the segregation. recycling (biological), management and utility

of o r p i c waste is shown through the flow chart in Figure 1

Figure 1: Flow chart for biological methods of organic solid waste recycling

Organic wastes

(Plastic, Nylon PVC, weighing) glass metals, etc ,)

I

(sorting, chopping

The followng are the three general methods in the bio-process~ng of organic wastes

I Anaaobic digestion 2 Composting 3 Vermicompostlng

1. ANAEROBIC DIGESTION : Digestion of organlc s o ~ l ~ d waste in the

absencence of free oxygen, is otherwise referred to as hot fermentation

method (Acharaya. 1940) Anaerobic d~gest ion process can be broadly

grouped into two malor s teps 1 ) A c ~ d fermentation, 2 ) Methane

fermentation In acid fermentation the hydrolytic fermentative, (acidogenic)

bacteria hydrolyse the complex polymeric substrates into organic ac~ds, alcohols,

sugars, H, and CO, In methane fermentation, fermentation of amino acids and

sugars takes place, where hydrogen producing, acetogenic organisms convert

the fermentation products into hydrogen, acetates and CO, In methane fermen-

tation of long-chain fatty acids and alcohols are converted to short-chain fatty

acids, and CO, Hydogenation of CO, releases methane in addition to acetate

digested methane which gets released

2. COMPOSTlNG This is the conversion of organic solid waste which is

r ~ c h ~n humus and plant nutrients, by m~croorganisms where the organic

res~dues of plant and animal origin get converted into manure Organic wastes

when app l~ed dtrectly to agricultural fields cause phytotoxicity and other

so11 environment related problems (Hsu and Lo. 1999) Composting I S a

trad~tional practlce ~n the transformation of organic waste by biological

methods and I S useful for the development of a productive sustainable

agricultural system(Parr eta1 ,1990) Composting process involves a

blolog~cal treatment in w h ~ c h aerobic thermophil~c microorganisms use

organlc matter as a substrate Dumping of organic wastes in open areas (land

fill~ng) causes environmental problems such as the accumulation of heavy

metals ~n soil, pollution of ground and surface waters due to leaching and

run-off of nutrients To solve such problems after the separation of solids

from slurry, the organic matter when composted under controlled

conditions provides a better alternat~ve ~n terms of pollut~on management

and manure production

A flow chart for the composting of an organic waste is presented in Fig. 2.

Figure 2 Flow chart for composting

1 Oranic solid waste 1

t Wet digestion (hentino miuino)

+ solid

post-treatment (mxlng, sortmg,etc )

storagdmarket~ng I (compost) I

Type of comporting: Compostlng process is div~ded Into two types based on aeration

A. Aerob~c compostlng

B Anaerobic cornposting

Thir is the conversion of organic solid wastes into an amorphous dark

brown to black colloidal bumus-like substance under conditions of optimum

temperature, moisture and aeration. This type of bio degradation is called

decomposition md tbe process is called composting. Enzymatic activity of

microorganisms aids for biodegradation. In aerobic composting

bacteria, fungi and actinomycetes are involved in the breakdown process.

la aerobic composting aeration is done once in IS days to help maintain

the moisture and temperature which aid for faster degradation. However it

is also dependent on microbial populations like cellulolytic and lignolytic

microbes (Khslma d Krishnamoben, 1995).

In storing organic manure like Iltters, farmyard manure etc., meant

for use in organic fanning. 20- 40% of nitrogen is lost (during stomp) thou&

gaseous emissions, besides the problem of leaching of the plant nutrients from

thc sum Orgnnic manure But cornposting (aerobic) prcvcnts the nutrient loss from

the organic solid manure, and aeration wben done once in a month, helps to

Improve the fertilizer value of the organic manure (Sommer and Dhal, 1999).

Dunng cunposth& orgao~c waste gets transformed into water soluble concentnted

organic and humic substances like humic acid, fulvic acid, besides other non

humic f i . This cornposted product has the advantage of improving the soil

structure. organic content of soil, suppnssing soil-borne plant pathogens, and

enhancing plmt growth (Szezech and Smolinska 2001; Tomati and Grappelli,

1988). Microbid composting of organic wastes is also termed as a controlled

microbial rerobic dcaqo&m procss. The mam products of this processff ~ T C CO,.

H,O, and minerds with a stabilized organic matter often called as humus.

B. Anrvobic composting

Anaerobic wmposting is the bacterial decomposition of organic waste in the

absence of free oxygen Anaerobic digestion of organic waste is usehl in treating

industrial wastes and other biological wastes like farm and municipal waste at much

lesser costs and is less energy intensive (Abbasi and Nipaney, 1993) The biological

method of treatment in an anaerobic digestion IS the same as in aerobic wmposting

Anaerobic wmpostlng is otherwise called as hot fermentation method because heat loss

during decomposition IS considerably reduced (Acharya, 1940)

Anaerobic m.icierobial Freah organic metabol~sm Stabilized organic matter (compost)

wrcite ' + CO, + H,O + Heat + CH, + H,

METHODS OF COMPOSTING

In the decomposit~on of organlc waste by composting. the different methods

generally followed are

Windrows method of composting

Windrows can be from 2 to 6 m In w~dth at the base and 1 to 3m

In height and of any length However most common windrow size is

3-5 m at the base and 2 to 3 m In height and somewhat triangular in shape

Large windrows require considerably more land area Small windrows when

not properly maintamed release odors whenever aerated (Kuhlman, 1990)

The m u n ~ c ~ p a l sludge is cornposted by any of the three following

methods Aerated srolrc prle operalron. ('onr,enlronal wrndrow process and

Aerated wrndrow process (Benedick et al ,1986)

Aerated static pile operation

Aerated static pile operation'involves mixing dewatered sludge with

bulking agent, such as wood chips followed by active composting in specially

constructed piles Induced aeration is provided during active composting and

agun during curing or drying The active composting per~od lasts at least 21 days

after which alternate pathways to produce finished compost may be used

Conventional windrow process

The dewatered sludge with bulklng agent is often supplemented with

an external amendment followed by formation In long wlndrow Composting

p e r ~ o d of an active w ~ n d r o w is 30 days or more The w ~ n d r o w is turned

period~cally t o aerate and to mix The curlng period for the compost 1s 30 days

A portion of the fin~shed compost I S used for recycl~ng and another portion is

stock p~ led for d ~ s t r ~ b u t ~ o n

Aerated windrow process

Thls method 1s s lm~la r to the convent~onal w~ndrow process except

that induced aeratlon to enhance actlve compostlng and drying IS provided

In addttlon to aeration by turning

I n d o n method

This is an aerobic method w ~ t h an adequate supply of oxygen ma~ntained

during the decompos~ t~on process The organlc waste and animal manure are

lald in a heap or spread In alternate layers of 15 cm thick and 1 5 - 2m wide

Layer o f organic waste is spread in hard upland site followed by 4-5 cm thick

animal manure This is followed by s p r ~ n k l ~ n g of soil with a small quantity of

lime or wood ashes of 30 mm thick In all T h ~ s layering is repeated every 1 5

7

- 2 0 m of height and the final layer should be of the compostable material

covered by a thin layer of soil, about 60mm thick 60 - 70% of moisture is

provided for each layer The heap is turned at 3, 6 and I2 weeks intervals

After 3 months the compost is mature The labour involved in turning,

moisture maintaining, construction of heap are the disadvantages in thls method.

Modified lndore method (Rolae, 1960)

This is a quick aerobic composting method The intermittent turning

of the compostlng ma te r~a l is the major factor In this method To ensure

adequate moisture, the compost heap is turned thoroughly at an interval of

every three days Finally in three weeks time a good compost 1s ready for use

This is an optional method if composting is t o be done in a shorter period

Bangalom method

In this method initially the decomposition is done aerobically followed

by anae rob ic decompos i t i on This method 1s o the rwi se called a s hot

fermentation method as heat loss during decomposition 1s cons~derably reduced

(Acharya,1940) In rural areas animal dung is used for maklng compost

The trenches of any length are made in any ava~able site, generally out side

of city A p ~ t of I m depth, l 5 m width and 3-4 m length is used The material

for compostlng IS filled into the pit upto 1 5 cm thickness Above this layer

dung is spread to 5 cm thickness This layering is repeated to a level of 30 cms

height above the ground The final layer on top is the compostable material

To maintain optimum moisture, water 1s sprinkled on each layer Above the

ground the heap 1s made into a dome shape and finally covered with 2 5 cm

of mud-plaster The compost gets ready after 5 t o 6 months Thls method takes

one-and-a-half t imes longer period than that in aerobic compost ing o f

lndore method

Modified Banglore method

This is called chinese high temperature composting method. It is a

combination of both aerobic and anadrobic method (Rapa, 1988) To make the

compost at high temperature after the heap is erected, hollow bamboo pipes are

inserted into it both vertically and horizontally In 2 -3 days the temperature ofthe

heap rises to 60 - 70°C The poles are then removed and the heap is plastered with

mud The plaster is broken after 15 days and the heap is turned thoroughly

If needed moisture is adjusted to appropriate levels The heap is replaced and

let? for natural decomposition The compost gets mature in about two months

FACTORS AFFECTING COMPOSTING OF ORGANIC WASTES

ABIOTIC FACTORS

I . Chemical nature of raw material: The organic wastes mostly present in

plant resldues are cellulose, hemicellulose, Ilgnln, carbohydrates and proteins

in nature Except for lignin and tannln, other residues decompose faster Lignin

has slow degradation compared to cellulose The chemical nature of raw

materials ~nfluences the composting period (Kale. 1998)

2. C:N ratio: C N ratlo is dependent on the mater~al supplied in the degradation

of organlc wastes There can be Nitrogen in the form of protein, organic

nltrogen and nitrogen bonded with organic compounds like nitro cellulose etc

Generally 30 to 50 C N ratio has been reported as suitable for composting

(Kale. 1998)

3. Moisture: 60 - 70% of moisture content is optimum for composting

Moisture content determines the duration for the degradation of organlc

waste (Govin,l99I. Atchley and Clark. 1979) and moisture is essential for

microbial activity However high moisture content creates anaerobic conditions

4. Aeration and temperature: Aeration which controls the internal environment

of the compost, regulates the decomposition process along with humidity and

temperature. It helps to avoid anaerobic condition and prevents loss of

ammonia (Jakobsm1992) The variation in temperature is due to change in

microbial population. A high tempemture destroys weed seeds, pathogenic

microbes, insects, wonns and prevents fly breeding (Falcon et a1.,1987).

5. pH: A pH of 6.1 - 7.8 is preferred for on land use, at pH of 5.5 - 8.5 for

landfills, 3.6-4.4 for wetland reclamation and 6.1-7.8 for soil stabilization

and multiple use (Bye, 1991).

pea of microorganiamr used in composting

Three main groups of microbes (1) Bacteria, (2) Fungi and (3) Actinomycetes

determine the biodegradation pattern of plant materials (Fergus1964; Chang

and Hudson.1967) and are mainly responsible for the physical and chemical

changes during wmposting (Thambirajah et al., 1995).

ROLE OF MICROBES IN ORGANIC WASTE RECYCLING (COMPOSTING)

Composting is a microbial degradation of organic solid waste.

Compost improves the soil structure, increases soil organic matter, suppresses

soil borne plant pathogens and enhances plant growth (Saviozzi et al., 1987).

Trichoderrna species has been used extensively in the composting of

sorghum stalk, wheat straw, leaves of Eugenia jombolana, chooped paddy

straw (Gaur and Singh, 1995). The Bacillus subrilis and Actinomycetes

species were isolated from thermophilic phase of solid waste compost (Strom,

1985a) and the B, subfilis, Actinomycetes sp. and Pseudomonos fluorescens

were identified from solid waste compost (Strom, 1985b). Since Z viride and

Bacillus species both possess lignolytic and cellulolytic properties they

induce humification process besides mineralization. Anaerobic microbial

composting of municipal solid waste induces volume reduction, methanol

production, energy extraction and humification processes (Kayhanir e t . d ,

1991). Phanerochaete chrysosporium (Mattis et al., 1983), anaerobic microbes con-

vert lignin, cellulose and lignocelluloses into low molecular weight

aromatic compounds besides liberating methane (Benner et a1.,1985). Shindia

(1995) reported Trichoderma species, to degrade various pectin substances. Vallini

et al., (1989) reported a continuous decrease in the number of cellulytic bacteria

and an increase in the number of cellulytic fungi during the composting of vegetable

tannery sludge. Basidromycetes are also strongly suspected of degrading tannins

because of their ability to break down lignin (Kirk and Farrell, 1987) in the composting

of oil palm fruits.

The five types of mlcrobes used for composting in the present study are:

Anaerobic bacteria

Bacteriodes, Clostridium, Butyrivihrio. Eubacterium, Bifidobacterium,

Lactobacillus, Desulfolibrio. Syntrophobacter wolinir, Syntrophomonas,

Methanobacterium formicicum, M. byantii, Methanobrevibacter ruminantiurn,

M arbor iph i lus , Methanospir i lum hungate i , Methanosarcina barker i i ,

Methanothrix species are the bacterial species involved in the anaerobic

digestion of organic waste. Anaerobic microbes are widely used in anaerobic

composting.

P. fluorescens is a good bio control agent against soil borne plant

pathogenic fungi and is an efficient root colonizer on crop plants. This

fluorescence bacteria produces antibiotics, siderophores, volatile compounds like

HCN and NH, which act as biological inhibitors of the plant pathogen

and provide nutrients to plants (Anith et al., 1999). In cultures it is a rod shaped

non-spore forming plant growth promoting rhizobacteria. Its role in compost is

well reported and this species oxidises large number of organic compounds

and possesses a celluloytic and pectinolytic activity (Schelegel, 1990). Strom

(1985a), has reported Pseudomonos s p . as growing at 50' to 55OC

in mushroom compost.

Actinomycetes

Actinomycetes is an antibiotic producing microorganism. These are

rnycelia type filamentous gram - positive bacteria. The distribution of

Actinomycetes in different soils varies but higher population is found in

cultivated soils (Nandi, 1968). Actinomycetes is antagonist against various soil borne

pathogenic fungi (Graff, 1971; Reddi and Rao, 1971). The antagonism ofActino-

mycetes towards Rhzzoctonra solani , the sheath blight pathogen

of rice is reported by Janaki (2002). In soil they are involved in the

decomposition and mineralization cycles with the production of extra cellular

enzymes, such as cellulases, chitinases and lignin peroxides. Many

Actinomycetes produce exo enzymes and can degrade many polymeric substances

such as starch, chitin, cellulose and lignin. Actinomycetes. Srreptomyces spp., and

Thermoactinomyces widely occur in self heating materials like

composting (Strom.198Sb). The favorable high organic nutrient content,

moisture, aerobic and neutral to alkaline pH condition in composts

and manures often helps in the colonization by Actionomycetes, mainly

thermopiles which grow well in decomposing organic matter and animal

manure (Leaderberg, 2000).

Trichoderma viride

This fungus is o n e o f t h e b io con t ro l agen t s and p roduces

hydrolytic enzymes like chitinases, b-I, 3 - glucanases, proteases and

volatile and non - volatile antibiotics (Elad et al , 1982) Its multi-beneficial

uses are well reported Neelamegam and Govindarajulu (2002) reported that

when T. vrrrde is combined with farmyard manure, it provides bet ter

con t ro l ove r t o m a t o plant d iseases bes ides Increasing g rowth o f t h e

seedlings Trrchoderma spp is used as a composting inocula (Gaur and

Singh. 1995), Trrchoderma spp has pectinolytlc activity (Shindia,l995) and

degrades various pectin substances 7: vrrrde produces hyper celluloytic

and myco ly t~c enzymes such as b - I . 3-glucanases, b- l 4 endoglucanase,

ch~t lnase and protease (Kurnar and Gupta, 1999). 11 produces volatile and

non - volatile antibiotics (Jebakumar et al . 2000), and T vrrrde is used as

lnocula for compost alds in hum~fication and minerallzatlon of carbon and

nltrogen of o rgan~c wastes (Back et al , 1992)

Bacillus subrtl~,,

T h ~ s bacter~al populat~ons occur in both thermophillc and mesophilic

phases o f compost Racrllus subt~lis . i s isolated in mesophilic phase

(Falcon et a1.1987) In the rmoph~ l~c solid waste compost out of fifteen taxa

~sola ted ten were of genus Racr1lu.r which included R subtilu (Strom,1985a)

After isolation o f Rocrllus species from soil. Rajan and Srlnlvasan,(l992)

repor ted l ~ g n o l y t i c ac t lv l ty on screening The Bacr1lu.s spp. lowered

humif icat ion index and dec reases t h e amount o f humlc subs t ances

Slmllarly t h e modification and t r a n s f o r m a t ~ o n pathway o f l ~ g n i n is

very s l o w in Bacrllus spp Tha t B. su6tili.1 1s an tagon i s t i c t o

plant pathogenic fungi and bacteria IS reported by Baker and Cook.(1982)

Advantrgm of comporting

1 Recycl ing o f organic solid w a s t e s r e su l t s in manure -a r ich

product useful for agricultural soils

2 Problem of odour odour-causing material gets rapidly decomposed

through aerobic metabolism

3 The rate o f water vaporization is related to the ra te o f waste

decomposition

4 The volume r educ t~on of the organlc waste I S a very important

aspect of gain in composting method

5 The composting system helps to control surface and ground water

pollution w ~ t h nutrients and heavy metals through the leaching

of raw organlc waste

6 In faster decomposltlon less materlal IS required for composting

7 The r a t e o f f a s t e r d e c o m p o s l t ~ o n s t rong ly Inf luences c o s t -

effectiveness o f facillty In terms of construction and rout ine

operation

8 Compos t lng I S a w ~ d e l y used method to treat many types o f

s o l ~ d wastes both as a means of d~sposal and recycling

9 Compost lng system helps t o suppress plant pathogens and is

useful as a pottlng med~a for horticultural plants (Inbar et a1 ,1988)

10 Addi t~on of compost In so11 increases the a v a ~ l a b ~ l ~ t y of enzymes

like amidase and urease (Serra et al . 1995)

D e c o m p o s ~ t i o n o f organlc mat ter alded by ear thworms is called

v e r m i c ~ m p o s t i n ~ The end products are hlghly enrlched plant nutrients and

the earthworms themselves constitute high protein feed A flow chart for

vermicomposting is presented in Fig.3

Figure 3: Flow chart for vermicomposting

+ l~iodegradable Organic wastes1

worms actlwty 9 1 STAGE-I

---- c -- - Separat~on of worms '

I From worked byproductJ L ------- -

Vanous stages

1 J STAGE -11

DEPOT STAGES

METHODS OF VERMICOMPOSTING

Two me thods o f v e r m i c o m p o s t ~ n g a re l d e n t ~ f i e d in t h i s

ecofriendly simple technology- Discontinuous systems of vermicomposting

and Continuous system8 of vermicomposting. Each system has its own

specific advantages and can be adapted to handle different volumes, under

different environmental factors or under different economic conditions.

Discontinour system

This system is applicable in windrows, heaps, pits, boxes, bins, or

even containers stacked in racks. This traditional method of vermi culture has

application on beds or windrows on the ground where organic material is put

up to 20-60 cm in depth. Earthworms always move upwards following the

addition of successive organic matter in layers on the surface of beds. Pits

below soil surface level have lower aeration but better water retention.

Heaps above the soil level have more lateral aeration but lower water

retention. Though heaps are easier to work with and construct, the option is

based on specific situations. In tropics horizontal windrows need large

areas of land for large scale production which is labour intensive. The

relatively low cost of human labour, low technology input, large availability

of land, abundance of substrates makes it one of the most feasible methods.

However vermicompost ing process has to be interrupted inorder to

separate the earthworms, and to collect the end product and then to start

again with a new successive series of feed (Lavelle,1999).

Continour system

In this method (Figure 4) a container filled with raw organic waste

is kept above the ground. It allows raw materials to be added at the top from

mobile supp l ie r s and the transformed end product to be col lected

mechanically at the bottom through mesh floors using breakers bars.

The 'Can - 0 - Worm' consists of one bottom level for leaching and three

Figum 4: Continuous vermicomposting reactor (not to scale) (Price J S 1987)

W o r n nch v a m l bcd

Cotl&on and srspsr of VCmlCBSte

w o r k ~ n g levels each havlng hundreds o f holes in the base to allow the

ear thworms to eat t h e ~ r way up to the next level by the time the third

w o r k ~ n g tray I S put in to place and filled w ~ t h fresh organic materials

The bottom tray is ready for harvesting of the earthworm castings and is

free from earthworms The worms then move upwards agaln and the process

continues A small scale system of this method designed and introduced

by AustralIan commercial groups IS utilized In homes and in other domestic

projects ( Lavelle. 1999)

FACTORS AFFECTING VERMICOMPOSTINC

All ab~o t i c factors that affect normal ae rob~c m~crob~a l compostlng also

influence vermicomposting process

ABIOTIC FACTORS

lkmperature

In vermireactor the temperature, moisture and aeration affect earthworm

activity Temperature is controlled by varying the retained depth of waste

between 200 and 500 mm Normally a temperature of 20-25°C in upper layer

of the composting (waste) material IS suitable 30°C and above temperatures

results in the death of earthworms (Price, 1987)

Moisture

Mois ture is a very Important factor for successful vermiculture,

since, water constitutes 70-90% of earthworms' body weight, and to prevent

water loss a similar environment IS deslred However over waterlng results in

accentuated d r a ~ n a g e problem, besides bottom layerdevelops anaerobic

c o n d ~ t ~ o n 70-80% (Neuhauser et a1 , 1980), SO-SO% (Hartenstein, et a1 ,1981)

of water content 1s su~table for vermlculture

Aeration

Aeration reduces high temperatures and prevents the heating o f

the organlc waste material It controls anaerobic conditions from setting in

Earthworms are partly self-aerating in a vermicompost

Tolerance to soil pH varies from species to species (Ghosh.1993)

A pH greater than 5 or less than 9 (>5 or <9) is optlmum Earthworms galn in

weight when pH of soil is around 7 0 (Kaplan et al . 1980) Cow manure helps

to regulate pH between 6 9 to 7 2 (Reinecke and Venter. 1987)

Electrical conductivity

0 5% of salt concentration causes loss of we~ght o r death of earthworms

An EC with a range of 0 9 to 1 5 mm ohms (Kaplan et al , 1980) is optimum

for their survival

C:N ratio

Some species of earthworms are capable of digesting material with

a higher C N ratio, even more than 20 C N ratio influences the activity of

earthworm C N ratio of the vermicompost is considered as one of the

Important factors influencing the rate of mineralization ( Kale, 1998)

Earthworm species used in vermicomposting

In India 385 species of earthworms be long~ng to 64 genera are

recognized of which about 10% of them constitute well known species

(Julka, 1999) These earthworm specles can be dlvlded into two main classes

Manure worms (red worms) and Soil processing worms. Although there

are nearly 6500 described species of earthworms In the world, only a few

are identified sultable for culturing In organlc waste materials The best known

specles with potential for waste management are Ersenra andre, (Red earth-

worm) I:' ferida (Brand~ng or tiger earthworm), Eudrl1u.s rlrge~rrar (African night

crawler), and Pc,rronyx excavatus (Or~ental earthworm) A few other species

1)rowida nepalet~s,s, Lamprro maurrrrr. Drchogasrer spp , Polyphererrma

rlotrgara. Amynrhos spp . Dendrobaena ocraedra. f:'rsetr~a hortensr.~ (Lavelle,

1999) have been used for compost ing under specific condit ions

For a potentlal vermlcornpostlng process earthworms w ~ t h the following

characteristics (Salhlanarayanan.1999) are best suited

I The worm should be capable of inhab~ting in high percentage of organic

material

2 Should possess high rates of consumption. assimilation and growth

3 Should possess high fecundity rate with low incubation period

4 Interval period bdween hatching and maturity should be less

5 Should possess high stability for environmental variations, fluctuations

6 Should be disease and stress resistant

ROLE OF EARTHWORMS IN ORGANIC WASTE RECYCLING

Earthworms belong to the phylum Annelids, order Oligochaeta,

class Clitellata Earthworms are terrestrial invertebrates that live in the soil

Earthworms do not feed on living parts of plants but on such parts in

which decay has already set in (Satchell. 1983)

Based on feeding habit of earthworms they are divided Into two types

In temperate regions 88% of earthworms are (humus feeder) detritivorous

feed~ng at or near soil surface and only 12% are geophagous (soil ingesting

earthworms) feed~ng on organic r ~ c h soil l ~ k e plant debris in the organic

material or dung Earthworms have been extensively utilized for the recycling

of a varlety of organ~c wastes l ~ k e mun~c~pal so l~d wastes (Ciavatta et a1.1993)

wheat straw (Bannik and Joergensen. 1993). Sewage sludge (Govi et al, 1993).

forestry waste (Martizez ~nigo and Almedros. 1994). vegetable waste (Vallin~

and Pera, 1989). farmyard manure (Jakobsen et al, 1990), sorghum stalk, wheat

straw. Paddy straw (Gaur and Singh. 1995). Colr pith jot him an^. 1994)

The four specles of earthworms used for recycling In the present study

are

Lampito rnauritii (Kinberg)

It is an anecic earthworm termed to be a "Peregrine" species as it

dominates from northern to southern regions of the Indian peninsula It has

a wide range of distribution and occurs in association with other species

of earthworms It is a detritivorous earthworm. This species is an effective

drilosphere burrowing through the soil depositing granular casts of moderate

size on soil surface Lamprto maurrtrr is a dominant species which is known

to promote soil communication and surface castings in dense soils (Habibullah

and Ismail. 1985) It also promotes mixing of organic matter with mineral matter

forming soil aggregates (Grace and lsmai1,1994). When L. murrtrr is used in

pressmud recycling, odour complicity is removed and there is significant

increase in micro and macro nutrients About 18 types of fungi were isolated

from the gut of L. maurrttr (Parthasarathi and Ranganathan, 1998) and they are

mostly cellulolytic fungi (Parthasarathy et al . 1997). L. maurrtrr is reported to

enhance the nutrient concentration of the feed substrate, particularly carbon

and nitrogen, and also boosts reproduction In pressmud feed (Parthasarathi

and Ranganathan, 2000a) lnactivatlon of the microb~al populat~on lower

stabil~ty of aged earthworm casts (Parthasarathi and Ranganathan, 2000b)

In the presence of pressmud I. rnaurrrrr demonstrated enhanced rate

of degradation but slow rates of growth and reproduction (Ramalingam, 1997,

Ramalingam et al . 2000)

Eudrilus engcniac (Kinberg)

1:udrrlus eugenrae, called as the African nightcrawler (Dominguez et al ,

200 I ), 1s an exotic earthwormspecies (Gobi et al . 200 1 ) 6 eugenrae is most

common In West African soils, and is used as a commerc~al vermiculture

species (Reinecke and Viljoen. 1988). a commercial breeder and as a potential

prolein source The cast released by the earthworm on so11 surface is in fine

loose granular shape (Kale. 1998) E euge~lrae similar to P rxcavatus is very

effeclive and adaptable in cultures under semi-natural cond~tlons E.eugenrae

Is used all over the would for agricultural waste degradation (post-

harvest stubble's,) sugar cane thrash, coir waste, and paper pulp, fecal

matter of cow, sheep, horse, biogas sludge, and poultry droppings (Kale

and Krishnamurthy, 1982, Kale and Bano, 1988 and Kale et al , 1992)

Though E. eugenrae, is a suitable species, it appears to be less tolerant

to cold temperatures and easily escapes during heavy rains (Neuhauser

et 111.1988, Rodriguez et a1.1986) An increased content of nitrogen,

phosphate, and potash is reported In the casts of both Lamprro rnourrlrr,

Eudrrlus eugenrae. (Parthasarathl and Ranganathan,2000a). E. eugenrae has

a faster feeding rate, higher moisture content in the casts,high microbial

population and h ~ g h enzymatic rate in both gut and casts (Vinotha, 1999)

The organic content of the substrate I S vital for supporting growth and

cocoon production in E eugenroe (Vlljoen and Relnecke, 1989)

Ocrochaerona Serrato(Gates)

It IS an endogelc earthworm specles generally found in the clay and clay

loamy so11 ofcoconut field, ground nut field, and paddy fields It I S a geophagous

earthworm specles and h a v ~ n g 80-1 SOmm length 3-4 mm diameter and

16 1-202 segments The Ocrochoerono species 1s reported to contaln protease,

amylase, Invertase, and cellulase enzymes ~n ~ t s gut (M~shra and Dash. 1980)

Perionyx cxcavalrs (Perrier)

I'erronyx excavaius known as blue worm and found in large areas of

trop~cal Asla (Gates. 1972) Europe and North Amer~ca (Edward and Fletcher,

1998), IS an epigeic found ~n organlc wastes This earthworm generally grows

to a length of 65 - 152 mm and 3 - 4 5 mm In d~arneter with 89 to 157

segments In total This t rop~cal earthworm is extremely prolific for use rn

vermlculture and easy to handle and easy to harvest I t I S an deal species for

trop~cal conditions and is called 6s orlental compost earthworm (Lavelle, 1999)

1' cxcuvorus and I;.eugenrae are both suitable specles for vermicomposting and

vermiculture in tropical climates(Dominquez et a1 ,2001) Maturation rate is

faster with early cocoon production than Eudrrlus eugeniae and Ersenra foetrda

(Reinecke et al , 1992). The vermicasts of this species are fine loose and

granular in shape on soil surface (Kale, 1998) Perionyx excava/us grows slowly

compared to other vermicomposting species (Reinecke and Hallatt,1989)

Advantages of vermicornpost

1 The Interactions between mlcrobes and earthworms during

vermicompos t~ng process have more beneficla1 than negatlve

effects (Brown. 1995)

2 Earthworm gut acts as a 'hot Spot' with Intense enzyme act lv~ty

for decomposit~on of organlc matter (Brussaard and Juma, 1996)

3 The vermlcast also offers a sultable base for free l tv~ng benefic~al

m~crobes whose a c t i v ~ t ~ e s are essential for releas~ng of nutrients In

the so11 to h ~ g h e r plants (Atlavinyte et al. 1971. Atlavinyte and

Vanagas 1982)

4 Verm~compost control plant pathogens and Increase the growth and

yield of plants

5 Verm~compost methodology reduces and removes bad odours, and

a numbers of unwanted flies etc (Ismail, 1997)

6 There I S considerable scient~fic ev~dence to suggest that plant and

human pathogens do not survlve the verm~composting process, so

if mater~als contalnlng pathogens are present they are for the most

part k~l led In passing through the earthworm gut (Sabine. 1983.

Tornati et al. 1988. Edwards and Bohlen. 1996)

7 Earthworm are used for the removal of heavy metals and pestic~de

from the contaminated soil (Jairajpur~. 1993)

8. Earthworm biomass obtained during vermicomposting is used as vermi

-protein for poultry and fish farms, (Edwards and Lofty, 1977)

9 In India. in Unani system of medicine in the preparation of external

applications for treating wounds, piles, chronic boils, sore-throat,

hernia, e tc .dr ied earthworms are used Other preparat ions taken

internally are for curing respiratory ailments, jaundice, rheumatic

pain etc

ORGANIC WASTE RECYCLING WITH SPECIAL REFERENCE TO

COIR PITH AND COFFEE HUSK

Coir plth is an agro industrial organlc waste Coconut husk is used

in the manufacture of coir fiber and the Industry In fast growlng in the country

due to increased area under coconut cultivat~on Coir p ~ t h I S a bulky waste

ma te r~a l from colr fiber industry and I S accurnulatted In Industrial yards

causlng environmental problems

Colr ptth IS a sultable material for both compostlng and verm~composting

(Gobi et al . 2001) Application o f b~otechnology for the conversion o f coir

plth into a useful biomass would not only solve the waste drsposal problem

but would a lso indirectly meet the growing energy crisis o f developing

countries

Coffee husk is one o f the by-products from coffee processing units

Approxlmetely three tons of by-products a r e generated and four tons o f

water is required to obtain one ton of dry dehulled coffee Usually coffee husk

is dumped In large open placesln go rges o r near rlvers causing water

pollution (Aranda and Barois, 2000) Perronyx excavates 1s a dominant

earthworm species found in coffee pulp piles on land (Perrier, 1872)

CHEMICAL NATURE AND YEARLY PRODUCTION OF COIR PITH

AND COFFEE HUSK

Coir pith

Coconut husk is a renewable agro waste arising out of extraction of

coconut Coconut being a perennial crop produces large quantitles of

materials such as leaves, flower stalks, spathes and petioles besides husk and

pcth These materials are rich In plant nutr ients and their

degradation adds considerable quantitles of organic matter to the soil

The husk I S a rlch source of K ' and 11 can absorb 6-8 times water by

11s weight The leaves and husk are used as mulch around the base of

coconut trees The husk 1s kept in one or two layers at the bottom of the

plt before plant~ng It 1s also burled In trenches of 0 5m wide and 0 4m deep in

between two coconut rows Coir p ~ t h I S another excellent material

contalnlng large proportions of cellulose and llgnln Coir plth and colr dust are

two wastes resulting from the extraction of fiber from cocunut husk

Thus colr pith is a waste of waste The extraction of one kilo of coir

fiber generates two k~los of coir pith (Joseph.1995) Though it decomposes

rather slowly. the coir pith being a rlch K ' source helps to retain moisture in

the soil for longer periods (Jothlmanl. 1994) The chemlcal composition

of coir plth presented in Table-1, ~nd~ca tes hlgh content of lignln 30(%) and

C N ratio of 1 1 2 1 (Joseph, 1995) The Production of colr fiber and coir pith

per year is presented in Table-2. Coir pith a light weight material, occupies

large space and its water absorbance is high C o ~ r dust 1s blown by wind,

does not burn completely, emits continuous smoke for several days and

causes air pollution Coir pith production and recycling process is

shown through Figure 5.

Figurn 5 Flow chart for wir pith production and recycling

Coconut husk 'r'

Production of Rope and other materials

Coffee husk

The coffee beans a re extracted from the fruit using wet

process Coffee pulp represents approx~mately 40% of the weight of fresh

f ru~ t Yearly product~on of the coffee pulp (husk) 1s presented in Table-2

Chem~cal composition of coffee husk is shown In Table-I. Disposal of

coffee waste is one of the major problems In coffee processing unfits

For one ton of dry de-hulled coffee production, three tons of by-products

are generated for whichfour tons of water is requ~red Fresh coffee beans

consist of 39% "depulpers" and 28 7% of weight on dry basis (Zuluaga.

1989)

Table 1. Chemical compostion of raw coir waste and coffee husk

Manganese (ppm) 257 73

Znc (pprn) 147 83

Copper (ppm)

C N rato 112 1 CN rum 2 7 84 1

Vohme (mm)

Table 2: Yearly production of cior fiber, ca r ptth, Green coffee and coffee husk (Values In rnult~ples of thousand metric tonnes)

Source F A 0 report. 2003

Figure 6: Flow chart for coffee husk production and recycling.

Coffee husk l c o ~ ~ ~ l

Production and recycling process with regard to coffee husk is

presented through Figure 6. Coffee wastes are generally dumped in large open

plles in gorgesor near rivers and cause both water and soil pollution (Aranda

and Barois.2000; Sera,2000). Coffee pulp is one of the natural best organic

residues in fresh condition and is mixed w ~ t h food for animals (Campabadal,

1987). However since coffee husk contains caffeine, polyphenols, tannins,

clorogenic, ferulic, and cafeicacids it is not a preferred feed for animals

(Gaime-Perraud et a1.,1991 a and b). In the absence of oxygen, coffee

waste turns acidic, hot and yellowish and is unfit for farmland use (Barois

and Aranda, 1995). However coffee husk can be transformed into useful

products for farmland and horticulture through environmental bio-

technological methods like vermicomposting and microbial composting.

This way the problem of enormous generation of main by-products in both

coffee and coir fibre industry can be resolved. Added advantage is the

Commercial benefit in organic farming and at larger national level in

generating export revenue.

28

AIM AND OBJECTIVE OF THE STUDY

1 to screen four specles of eathworms- Lamprto maurrtrr, Kinberg,

Eudrr lus eugenrae , Kinberg, Octochaetona se r r a t a , Gates and

Perronyx excavatus, Perrier-for their ability to recycle colr pith and

coffee husk with different feed combinations

2 to analyse the rate of vermlcasts and biomass product~on besides

analyz~ng the nutrient status of the vermlcasts (of coir pith and coffee

husk) obta~ned through vermtcompostlng by these four species of

earthworms

3 to analyse the rate of compost~ng of coir pith and coffee husk using the

microbes-Pseudomonas sp , Bacrllus sp , Trrchoderma sp . A~~~~~~

and A n a e r o b ~ c b a c t e r ~ a and to analyze the nutrlent s ta tus o f

composted products

4 t o analyze the rate of recycl~ng through vermlcompostlng of the

composted products of colr p ~ t h and coffee husk and to compare their

nutrlent status w ~ t h vermlcasts and composted products

5 to demonstrate the effect of vermlcasts of coir p ~ t h and coffee husk

on germination of black gram seeds and plants as well

6 to demonstrate pathogen suppressiveness of coir pith and coffee husk

vermlcasts a g a ~ n s t plant pathogens-Rhrzoctonra solanr and

Rhrzopus s/olonijer

7 t o analyse and Identify the actlve compounds/functional groups

involved in the pathogen suppression attr~bute of the verm~casts of coir

pith and coffee husk through lnfra Red Spectroscopy and to compare

with the functional groups present In the composted coir pith and

coffee husk