Treatment of kitchen waste by microbial culture

IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 03 Special Issue: 06 | May-2014 | RRDCE - 2014, Available @ http://www.ijret.org 37
TREATMENT OF KITCHEN WASTE BY MICROBIAL CULTURE
Anuradha.S.Tanksali1
, Sridevi.S.Angadi2
, Asha.Arwikar3
1
BLDEA’s V.P.P.G.H College of Engineering and Technology, Bijapur-586103, India.
2
3
Abstract
The sight of a dustbin overflowing and the stench rising from it are all too familiar sights of a crowded city. As we cross it, we look
away from it and hold our nose. If we give a thought to it, we also have a role to play in the creation of this stench. We can also play a
role in the lessening of this smell and reducing the dumping of the waste, if we follow proper methods of disposal of the waste
generated in the house.
The growth of urban cities and ever increasing human population and the misuse and abuse of the environment has led to increased
accumulation of waste materials which is polluting water, air, soil and increased risk to human life in the form of epidemics.
There are number of methods for solid waste management from ancient times. Some of the methods are sanitary land-fill, vermi-
composting, burning, incineration, biogas generation, anaerobic composting. These methods will not prove effective in some of the
circumstances such as high temperature, high moisture content. So, there is need to find such a method which suites to all the
environmental conditions & circumstances.
The above said problems can be solved by the new method of waste management viz. Mechanical Biological treatment (MBT). In this
method, the culture called mega-bacillus is considered as key agent for degradation of organic waste.
In the present study, kitchen waste is decomposed using mega-bacillus. A total quantity of 20 kg green waste was converted to 4.074
kgs of manure in just 16 days with a pH of 7.96, C : N ratio of 25.07:1 and a Nitrogen content of 2.15% which are within the desirable
parameters for increasing the yield of crop & maintaining the fertility of soil.
Keywords: Biological treatment, Solid waste, Aerobic composting, Compost.
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1. INTRODUCTION
1.1 Health Impacts of Solid Waste (5)
Modernization and progress has had its share of disadvantages
and one of the main aspects of concern is the pollution it is
causing to the earth – be it land, air, or water. With increase in
the global population and the rising demand for food and other
essentials, there has been a rise in the amount of waste being
generated daily by each household. This waste is ultimately
thrown into municipal waste collection centres from where it
is collected by the area municipalities to be further thrown into
the landfills and dumps. However, either due to resource
crunch or inefficient infrastructure, not all of this waste gets
collected and transported to the final dumpsites. If at this stage
the management and disposal is improperly done, it can cause
serious impacts on human health and problems to the
surrounding environment.
The group at risk from the unscientific disposal of solid waste
include – the population in areas where there is no proper
waste disposal method, especially the preschool children;
waste workers; and workers in facilities producing toxic and
infectious material. Other high-risk group includes population
living close to a waste dump and those, whose water supply
has become contaminated either due to waste dumping or
leakage from landfill sites. Uncollected solid waste also
increases risk of injury, and infection.
1.2 Occupation Hazards Associated with Waste
Handling (5)
1.2.1 Infections
a) Skin and blood infections resulting from direct
contact with waste, and from infected wounds
b) Eye and respiratory infections resulting from
exposure to infected dust, especially during landfill
operations
c) Different diseases that result from the bites of
animals, feeding on the waste
d) Intestinal infections that are transmitted by flies,
feeding on the waste

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1.2.2 Chronic Diseases
a) Incineration operators are at risk of chronic
respiratory diseases, including cancers resulting from
exposure to dust/ash and hazardous compounds
1.2.3 Accidents
a) Bone and muscle disorders resulting from the
handling of heavy containers
b) Infecting wounds resulting from contact with sharp
objects
c) Poisoning and chemical burns resulting from contact
with small amounts of
hazardous chemical waste mixed with general waste.
d) Burns and other injuries resulting from occupational
accidents at waste disposal sites or from methane gas
explosion at landfill sites.
2. IMPORTANCE OF WASTE REDUCTION (5)
In the affluent countries, the main motivations for waste
reduction are frequently related to the high cost and scarcity of
sites for landfills, and the environmental degradation caused
by toxic materials in the deposited wastes. The same
considerations apply to large metropolitan areas in developing
countries that are surrounded by other populous jurisdictions.
The places that currently do not have significant disposal
pressures can still benefit from encouraging waste reduction.
Their solid waste departments, already overburdened, cannot
afford to spend more money and effort on the greater
quantities of wastes that will inevitably be produced as
consumption levels rise and urban wastes change.
Solid waste managers in developing countries tend to pay little
attention to the topic of reducing non-organic wastes because
the wastes they collect are between 50% to 90% organics, dirt
and ashes. These municipal wastes, however, are amenable to
composting or digestion, provided they contain very low
levels of synthetic materials. Solid waste departments thus
have an interest in promoting diversion of synthetic
recyclables from the waste stream.
Each household generates garbage or waste, day in and day
out. Items that are no longer needed or do not have any further
use, fall in the category of waste and we tend to throw them
away. There are different types of solid waste depending on
their source. In today’s polluted world, learning the correct
methods of handling the waste generated has become
essential. Segregation is an important method of handling
municipal solid waste. Segregation at source can be
understood clearly by schematic representation. One of the
important methods of managing and treating wastes is
composting. As the cities are growing in size and in numbers
problems such as the generation of plastic waste, various
municipal waste treatment and disposal methods are now
being used for trying and resolving these problems. One
common sight in all cities is the rag picker who plays an
important role in the segregation of this waste. Garbage
generated in households can be recycled and reused to prevent
creation of waste at source and reducing amount of waste
thrown into the community dustbins.
2.1 Four Rs Concept for Waste Management (5)
2.1.1 Refuse
Instead of buying new containers from the market, use the
ones that are in the house. Refuse to buy new items though
you may think they are prettier than the ones you already have.
2.1.2 Reuse
Do not throw away the soft drink cans or the bottles; cover
them with homemade paper or paint on them and use them as
pencil stands or small vases. Alternately, you can store them
and sell it to the kabariwalla who takes these for recycling.
Reuse the plastic bags for shopping again and again. It is
better if you use shopping bags made of cloth or jute, which
can be used over and over again.
2.1.3 Recycle
Segregate your wastes so that non-perishable wastes are easily
collected and taken for recycling. Dig a small pit to compost
your organic wastes like kitchen wastes at your home.
2.1.4 Reduce
Reduce the generation of unnecessary waste, e.g. carry your
own shopping bag when you go to the market and put all your
purchases directly into it.
3. METHODS OF SOLID WASTE MANAGEMENT
(6) (10)
3.1 Open Dumping
The solid waste generated in the society is dumped in the open
place outside the premises of the city. The following are the
disadvantages of this method:-
a) Bad smell & odour.
b) Air pollution.
c) Environmental problems.
d) Requirement of large area.
3.2 Open Burning
In this method the collected waste is dumped in open ground
& then it is burnt. The disadvantages of this method are:-
a) Burning creates bad smell.
b) As waste is burnt it leads to air pollution which
affects the ozone layer, as it contains lot of harmful
gases.

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c) Smoke generated from burning causes respiratory
problems in humans.
d) Affects the fertility of soil.
e) Creates huge amount of ash for which another
disposal methods should be found.
3.3 Sanitary Landfill
The sanitary landfill can be described as engineered burial of
waste. Sanitary landfill is defined as a method of disposing of
waste on land without creating nuisance or hazard to public
health or safety, by utilizing the principals of engineering to
confine the waste to the smallest practical area & reduce it to
smallest practical volume & to cover it with layer of earth at
the conclusion of each days operation or at such more frequent
intervals as may be necessary. The disadvantages of sanitary
landfill are:-
a) The microbial degradation is at a very slow rate when
compared with the other biological treatment
systems.
b) When too much organic matter is buried without
consideration for methane production, there is
possibility of potential fire hazard.
c) When there is less than 60% moisture, it is difficult
for bacteria to grow.
d) There is production of carbon-di-oxide which is
troublesome due to its density.
e) Lot of land fill gases are emitted which are to be
handled.
f) There is release of leachate, leading of pollution of
surface & ground water.
g) The land used for filling cannot be reused for a longer
time.
h) The waste after treatment does not have any reusable
value.
3.4 Incineration
Incineration is a waste treatment process that involves the
combustion of organic substances contained in waste
materials. Incineration and other high temperature waste
treatment systems are described as "thermal treatment".
Incineration of waste materials converts the waste into ash,
flue gas, and heat. The ash is mostly formed by the inorganic
constituents of the waste, and may take the form of solid
lumps or particulates carried by the flue gas. The flue gases
must be cleaned of gaseous and particulate pollutants before
they are dispersed into the atmosphere. In some cases, the heat
generated by incineration can be used to generate electric
power. The disadvantages of this method are:-
a) The highly toxic ash must be safely disposed off.
Additional landfill is required.
b) Incinerators emit varying levels of heavy metals such
as Vanadium, Manganese, Chromium, Nickel,
Arsenic, Mercury, Lead and Cadmium, which can be
toxic even at very minute levels.
c) Building and operating waste processing plants such
as incinerators requires long contract periods to
recover initial investment costs, causing a long term
lock-in period.
d) Some incinerators are visually undesirable.
3.5 Bio-gas (Anaerobic composting process)
Biogas typically refers to a gas produced by the biological
breakdown of organic matter in the absence of oxygen.
Organic waste such as dead plant and animal material, animal
faeces, and kitchen waste can be converted into a gaseous fuel
called biogas. Biogas originates from biogenic material and is
a type of bio-fuel. Biogas is produced by the anaerobic
digestion or fermentation of biodegradable materials such as
biomass, manure, sewage, municipal waste, green waste, plant
material, and crops. Biogas comprises primarily methane
(CH4) and carbon dioxide (CO2) and may have small amounts
of hydrogen sulphide (H2S), moisture and siloxanes. The gases
methane, hydrogen, and carbon monoxide (CO) can be
combusted or oxidized with oxygen. Biogas can be used as a
fuel for any heating purpose, such as cooking. It can also be
converted to electricity. Along with the advantages there are
disadvantages of Bio-gas which are listed below:-
a) Biogas contains contaminant gases which can be
corrosive to gas engines and boilers.
b) Digestate must meet high standards in order to be
used on land without
detrimental, effects on agricultural uses especially
food crops.
c) Produces a limited quantity of energy and is
dependent upon location. The plant needs to be
established near to feedstock and energy users.
d) There is little or no control on the rate of gas
production, although the gas can, to some extent be
stored and used as required.
e) Biogas needs to be cleaned of H2S prior to power
generation.
f) Compost needs dewatering & drying before use.
i) Requires skilled labour & supervision.
j) It works costly due to the establishment of digester,
dewatering & biogas cleaning system.
3.6 Composting
Composting is very similar in its action to a sanitary land fill
but is a controlled microbial reaction yielding a stable end
product much sooner. Composting is a method in which
putresible organic matter in the refuse or solid waste is
digested aerobically & converted into humus & stable mineral
compounds. Composting removes the readily degradable
organic matter from the garbage & produces a stable material
(Nitrogen rich manure) that can be used to recover waste land
or to grow food crops through the bacterial agencies.
Bioconversion of organic resides is carried out by different
groups of heterotrophic micro-organisms (bacteria, fungi,

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acitinomycetes & protozoa). The organic material present in
the municipal wastes can be converted into stable form either
aerobically or anaerobically.
In case of aerobic decomposition micro-organisms oxidized
organic compounds to CO2, NO2 and NO3. Here carbon is
used as a source of energy and nitrogen is recycled. This is an
exothermic reaction, hence temperature rises.
Benefits of Compost:-
a) Composting yields a product which contains plant
nutrients (1% to 2% of NPK) as well as micro-
nutrients which can be utilized for growth of plants.
b) The solid waste volume is very much reduced; this
reduces the cost of transport & application in the
field.
c) The plant nutrients are converted to such forms that
they get released gradually over a longer period &
don’t get leached away easily.
d) It is known to contain trace elements such as Mn, Cu,
Bo, Mo which are essential for growth of plants.
e) It is a good soil conditioner & increases the texture of
soil.
f) It improves soil tilt & aeration, aids in root
penetration, loosens soil. Adds humic acid, organic
matter & nitrogen to soil, creating more fertile soil.
g) It increases water retention and improves the ion
change of soil reducing the need to irrigate.
h) It observes more radiant energy warming the soil,
increasing the growth of shrubs & trees.
i) It increases the buffering capacity of the soil.
Factors affecting composting process
a) Organisms: Bacteria, actinomycetes, fungi are
involved in the process.
b) Use of cultures: Innovators, enzymes hasten the
composting process.
c) Moisture: Optimum is 50 to 60%, less moisture
content reduces metabolic activity. But more
moisture content would set anaerobic conditions.
d) Temperature rises not appreciable.
e) C: N ratio of 30 is favourable for rapid composting.
f) Addition of sewage and sludge is done to maintain C:
N ration at optimum levels.
g) Aeration is done to maintain oxygen rate.
Methods of Composting
Method selection is an important factor. The operational cost,
capital investment, labour, space requirements and production
rate decides the type of method. The composting methods can
be classified into three sections:-
a) Manual method
b) Mechanical method
c) Microbial method
Manual composting can be done by Bangalore (Anaerobic)
and Indore (Aerobic) method, with underground trenches and
windrows respectively.
In these methods alternative layers of waste and cattle dung
are used.
Some of the common types of mechanical methods are,
1. Windrow composting
a). Passive windrow
b). Turned windrow
2. Aerated static pile composting
3. In-vessel composting
Windrow composting is one of the oldest and simplest
methods of composting. Windrows of 8 to10ft height and 20
to 25ft wide at the base with a front-end loader are used. It is
needed to turn the windrow once per year. High rate
systems are turned twice per week Complete composting is
accomplished in 3 to 4 weeks.
Aerated static pile composting is used to compost a wide
variety of organic wastes including yard waste or separated
MSW. The aerated static pile system consists of aeration or
exhaust piping over which the processed organic fraction of
MSW is placed. Typical pile heights are about 7 to 8ft (2 to
2.5m). A layer of screened compost is often placed on top of
the newly formed pile for insulation and odour control. Each
pile is provided with an individual blower for more effective
aeration control, so as to provide oxygen for biological
conversion and to control the temperature within the pile.
Complete composting is obtained in a period of 3 to 4 weeks.
In-vessel composting is accomplished inside an enclosed
container or vessel of any shape. This is divided into two
major categories; plug flow and dynamic. In plug flow system
the relationship between particles in the composting mass
remains same throughout the process, whereas in dynamic
system the composting material is mixed mechanically during
the processing. The detention period is from 1 to 2 weeks but
requires 4 to 12 weeks curing period.
4. MICROBIAL METHOD (MECHANICAL
BIOLOGICAL TREATMENT)
This is the advanced technique of solid waste management.
This method works on aerobic decomposition of organic
matter. In this method the generated MSW is segregated and
then crushed in the shredding machine. The mega-bacillus
culture and saw dust are added to the crushed waste and mixed
properly. The culture consists of essential minerals and amino
acids to bring about the decomposition. The mixture is then
kept in pits or containers for decomposition. The final product
is sieved and marketed.

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4.1 Culture Details (4)
Mega Bacillus (Bacillus Subtilis) also known as hay or grass
bacillus is a gram-positive, catalase-positive bacterium. It is a
member of genus Bacillus. It is rod-shaped and has the ability
to form a tough, protective endospore, allowing the organism
to tolerate extreme environmental conditions. They are
resistant to ultraviolet radiation, high temperature, extreme
freezing and chemical disinfectants. These produce useful
enzymes like amylase, protease, cellulose, and lipase which
help in decomposing the organic matter. This species is
commonly found in soil, more evidence suggest that B.subtilis
is a normal gut commensal in humans.
Fig-1 Bacillus Subtilis
4.2 Advantages of use of Mega-Bacillus Culture (8)
(9)
Apart from converting the organic matter in a eco-friendly,
nutrient rich compost, there are many more advantages of
mega bacillus, they are
a) Degradation of greases, fats and oil.
b) Degradation of detergent in industrial effluent and
municipal sewage.
c) Degradation of cellulose matter such as the effluent of paper
factory.
d) Rapid flocculation.
e) Effectively reduces BOD and COD in wastewater.
f) Keeps drain lines flowing smoothly; reduces the amount of
pumping.
g) Reduces offensive odours.
h) Suppresses green algae.
i) Increases population of zoo plankton.
j) Restores damaged aquatic life.
Fig-2 Mega-Bacillus Culture
4.3 Precautions in MBT Method
a) Regular mixing is required.
b) A moisture content of 60% is to be maintained.
c) Ideal temperature for MBT is 350
C to 370
C.
5. MBT PROCESS (8) (9)
The waste is collected from different sectors and is segregated.
The bio-degradable waste is shredded or crushed with the help
of mechanical means and mixed with saw dust or baggasse, in
order to maintain the moisture content to 60 to 70 %
approximately. The culture is mixed with waste and filled in
containers and brick pits and allowed for decomposition.
Regular mixing results in faster decomposition.
6. CASE STUDY
In this project the wastes used are, green waste (vegetable and
kitchen waste).These wastes were collected from the market,
canteen as well as college mess. The waste comprised of
different left over putrefied vegetables such as cabbage,
cauliflower, carrot, brinjal and leafy vegetables. A small
amount of non-biodegradable fraction was segregated. The
waste proportions used were,
1. Vegetable waste = 8.75 kg
2. Kitchen waste = 8.33 kg
3. Saw dust = 2.92 kg
4. Culture = 75 mg
5. Total = 20 kg (Except culture)

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Fig-3 Collection of kitchen and vegetable waste
Fig-4 Shredding of the waste
Fig-5 Mixing and placing for decomposition
Temperature was noted daily using a thermometer. Moisture
content was measured by oven. The temperature observed
during the starting days of composting process was 38.70
C.
During the decomposition process the temperature rose from
400
C to 600
C and reduced as the process reached completion.
After the composting process organic carbon (OC) and major
nutrients like total nitrogen (N), total phosphorus (P),
potassium (K), calcium (Ca) and magnesium (Mg) were
analysed. A pH of 9.76 was seen throughout the process.
7. RESULTS AND DISCUSSION
A total of 4.074 kgs of manure was obtained after 16 days and
the analysis results are as follows,
Fig-6 Analysis result

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Fig-7 Final product of MBT
Table 1 Nutrient Analysis
Checking the nutrients of compost obtained from MBT it was
observed that the manure of MBT waste possessed
significantly higher concentrations of the nutrients which are
required for good growth of plants and the time consumed in
the process was very less i.e., 16 days.
8. ECONOMICS OF BIO-COMPOST
This project can be started from any available fund, starting
from Rs. 10,000/-. Raw materials are available easily and
locally in abundance. It brings about successful organic
farming, which is very easy to market. The end product bio-
compost based humus bio-fertilizer has multiple utility. It can
be used in farms for seasonal crops, for week soil
improvement, wasteland development etc. It is an Eco-
Technology and the project is installed on the soil in its natural
conditions, hence there is no chance of failure of the project. It
is labour intensive industry; raw material is locally purchased
from local suppliers thereby generating employment. Another
plus point is on organic manure there is no State or Central
Sales Tax. Income Tax is exempted for 10 years for industry
which is producing organic manure from wastes. All
biodegradables are converted into organic manure, so all
villages and towns can be kept clean. The use of chemical
fertilizers & pesticides can be reduced to 50% so pollution of
water and air can be reduced.
9. LIMITATIONS
MBT method cannot treat the waste such as pieces of plastics,
polythene and polystyrene foam, iron or steel scrap. It requires
machines for shredding or crushing.
10. CONCLUSIONS
This project is eco-friendly and one stroke solution of most of
the burning problems like pollution, unemployment,
development of rural area, waste land development, poor
health, declining yield, improvement of soil structure,
porosity, poor soil fertility and excessive use of chemical
fertilizers and pesticides.
The MBT method can be successfully used to decompose the
vegetable & kitchen waste and converted into useful eco-
friendly manure. It undergoes more effective aeration leading
to faster decomposition and better NPK value of the manure.
The amount of culture used was very less. Though initial
investment is high, in the form of shredding machine it proves
to be more economical in future.
FUTURE SCOPE
It has been estimated that organic resource available in our
country can produce about 20 MT of plant nutrients (NPK).
The five major crops paddy, jowar, wheat, bajra and maize
alone are estimated to yield approximately 141.2 MT of straw
and legumes add another 10 MT. An estimated domestic waste
of about 25 MT, cattle manure of 320 MT and poultry manure
of 3.3 MT, is generated annually in India. This tremendous
agro waste and city garbage can is converted into valuable
agricultural input along with a safe and clean environment.
Instead of saw dust, baggasse of sugar industry waste can also
be used.
REFERENCES
[1] Applied and Environmental Soil Science Volume 2010
(2010), Article ID 967526, 13 pages
doi:10.1155/2010/967526
[2] Australian journal of Basic and Applied Sciences,
3(4):3671-3676,2009, ISSN 1991-817815
[3] Centre for earth resources research & management,
Malaysia.
[4] “Effective Synthesis of Bio-Nylon materials using
Bacillus”, by M.Ashiuchi, 2007.
[5] "Healthcare Waste Management for primary health
facilities". Centre for Renewable Energy, Appropriate
Technology and Environment
Sl.No Nutrients MBT
1 Ph 7.96
2 EC 260
3 Total N 2.15%
4 Total P2O5 0.82%
5 K2O 2.11%
6 OC 53.92%
7 C:N 25.07:1
8 Zn 60 ppm
9 Cu 0 ppm
10 Fe 300 ppm
11 Mg 0.19 %
12 Ca 0.8 %
13 B 0 ppm
14 S 0.14%

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[6] Hickmann, H. Lanier, Jr. (2003). American alchemy:
the history of solid waste management in the United
States. ForesterPress. ISBN 978-0-9707687-2-8.
[7] Prakriti, Centre for Management Studies, Dibrugarh
University.
[8] Sanitization and composting of municipal solid waste-
by J.M.S. Biotech Pvt.ltd Mysore.
[9] Site visit to Save environment engineers pvt.ltd Pune
and actual details are collected from the unit.
[10] Solid waste management in developing countries- by
A.D.Bhide, B.B. Sudaresan.
BIOGRAPHIES
Prof (Smt) A.S.Tanksali , M.Tech (Env),
working as Asst. Prof in Civil Engg Dept of
BLDEA’s CET, Bijapur
Prof (Smt) S.S.Angadi , M.Tech (Strs), working
as Asso. Prof/HOD in Civil Engg Dept of
Prof (Smt) A.S.Arwikar , M.Tech (Env),
working as Asso. Prof. in Civil Engg Dept of

Treatment of kitchen waste by microbial culture

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