BACKGROUND OF THE INVENTION
Rapid industrialization and population explosion has led to the migration of people from villages to cities, which generate thousands of tons of municipal solid waste daily. The municipal solid waste amount is expected to increase significantly in the near future as the country strives to attain an industrialized nation status by the year 2020. The management of municipal solid waste is going through a critical phase, due to the unavailability of suitable facilities to treat and dispose of the larger amount of municipal solid waste generated daily in metropolitan cities. Unscientific disposal causes an adverse impact on all components of the environment and human health. The waste generated is consequently released into the nearby environment. Consequently, the management of the municipal solid waste needs to be revamped to accommodate the changes in the quantity and quality to ensure the longevity of the environment. Due to several legislative, environmental, economic and social constraints, the identification of most sustainable disposal route for municipal solid waste management remains an important issue in almost all industrial segment. Generally, municipal solid waste is disposed of in low lying areas without taking any precautions or operational controls. Current citizens are living at a

time of unprecedented economic growth and changing lifestyles. Unsanitary conditions on the streets and air pollution in the cities will widen the gap between their expectations due to the rapidly changing perception of their “being” and “where they belong” and the prevailing conditions, resulting in plummeting quality of life.
Therefore, municipal solid waste management is one of the major environmental problems of megacities. It involves activities associated with generation, storage, collection, transfer and transport, processing and disposal of municipal solid wastes. But, in most cities, the municipal solid waste management system comprises only four activities, i.e., waste generation, collection, transportation, and disposal. The management of municipal solid waste requires proper use of the municipal solid waste that can help the environment (Municipal solid waste management in Indian cities, Bundela P.S et al, INTERNATIONAL JOURNAL OF ENVIRONMENTAL SCIENCES Volume 1, No 4, 2010).
Landfilling or burning of the municipal solid waste materials are well known methods in general. Landfill method is easy to handle but the major drawback of the landfilling is surface and groundwater pollution by heavy metals and organic contaminants due to municipal solid waste. Another most popular way adopted by the villagers is burning of the waste in open area. In villages without heavy equipment, burning can provide a way of managing the dump so that a clear access is maintained. But, burning garbage is associated with its own risk. It creates toxic smoke. Uncontrolled burning is also a serious

fire risk. Burning of the waste produces higher amount of smoke which can cause major health problems such as, cancer, functional limitation, physiological impairment, asthma etc.
JP 6108075 discloses method for production of solid fuel from waste material. The method discloses solid fuel of a high calorific value produced by compression-molding easily with a less fuel consumption and an improved effect of sterilizing and deodorizing garbage. In this invention CaCO3 and pulverized coal are used with CaO6 to perform in which use of coal and CaCO3 makes the method more costly.
EP 10425346.3 discloses method for the production of a fuel from waste wherein waste is passed from the various channels for drying. The method comprises the sending of the waste (USW) along a transformation path in such a way that it goes through in succession the operations of grinding, screening, drying and compacting to obtain the solid (WDC). There is no treatment disclosed for deodorizing or treating the waste to make it free from pathogens which makes method hard and risky to perform because of foul odour and presence of pathogens.
Thus, the above difficulties are evident of the reason that there is an instant need of such type of process which is eco-friendly with high calorific valued fuel without foul odour and free from pathogens.
OBJECT OF THE INVENTION

The main object of the invention is to provide a process for converting municipal solid waste (MSW) to solid fuel which has higher calorific value compared to input MSW.
Another object of the invention is to disclose a process for converting municipal solid waste to solid fuel without any leachate generation.
Further object of the invention is to provide a process for converting municipal solid waste to solid fuel which is free from foul odour and pathogen.
Still another object of the invention is to disclose a process for converting municipal solid waste to solid fuel which is eco-friendly and consumes less energy.
Yet another object of the invention is to provide easy segregation procedure to recover recyclable materials and enhance revenue.
SUMMARY OF THE INVENTION
The converting method of waste materials to solid fuel is an eco-friendly method in which inoculums made from the naturally occurring strains of Lactobacillus and Saccharomyces are used to provide an odourless and pathogen free environment during the whole process. In the present invention municipal solid waste is collected and treated with microbe by mixing the inoculums made from the naturally occurring strains of Lactobacillus and Saccharomyces with municipal solid waste. After treatment heap is prepared and it is left to attain specific temperature to reduce moisture and to remove stickiness of

municipal solid waste. Then, treated waste is fed to Trommel or Rotary Screen for size separation. Magnetic separation and eddy current separation are done for removal of ferrous and non-ferrous matter. Mechanical equipment is applied to remove stone and other heavy matter. Application of different equipments like rotary screen and shredding machine are utilized for size separation and size reduction to recover biomass, recyclable and non-recyclable materials. The shredded biomass is send to the pneumatic conveyor for cleaning of biomass to remove dirt, dust and other materials similar to thereof. Finally, the cleaned biomass is subjected to make Refused Derived Fuel (RDF) like briquettes, pellets and fluff.
BRIEF DESCRIPTION OFDRAWINGS
Figure 1 shows temperature gradient of municipal solid waste to solid fuel treatment.
Figure 2 shows pH gradient of municipal solid waste to solid fuel treatment.
Figure 3 shows moisture gradient of municipal solid waste to solid fuel treatment. Case 1 and Case 2 indicates input moisture content of collected waste that is 40% and 60% respectively.
Figure 4 shows flow diagram of process steps from receiving municipal solid waste to preparing heap or windrows.
Figure 5 shows flow diagram of process steps after preparing heap or windrow to molding into final product(s).

DETAILED DISCRIPTION
The nature of the invention and the manner in which it is performed is clearly described in the specification. The invention has various components and they are clearly described in the following pages of the complete specification.
The process for converting waste materials to solid fuel is an eco-friendly method to provide high calorific valued solid fuel by using Inoculum made from the naturally occurring strains of Lactobacillus and Saccharomyces to provide an odourless and pathogen free conditions throughout the process. Also the present method gives better production of fuel without leachate formation.
Lactobacillus is human friendly bacteria that can be found in the gut of the humans. They are major part of the lactic acid bacteria group, because most of its members convert lactose and other sugars to lactic acid. Lactobacilli are mainly used in fermentation industries. Lactobacillie strain is readily available in the market. In the present invention readily available powder of SPORLAC® is used.
Saccharomyces is unicellular, saprophytic fungi and the most popular fungi that mainly considered very important in food production such as wine, bread, and beer. Many members of this genus are considered very important in food production. It is known as the brewer's yeast or baker's yeast. Saccharomyces is purchased from Miskin Foods Pvt Ltd, Kalupur, Ahmedabad.
Municipal solid waste disposal is the major issue of most of the countries and waste management system has problems such as varying

composition of organic, non bio-degradable, moisture, foul odour and fly, leachate generation, difficult segregation of municipal solid waste due to stickiness and moisture, presence of pathogen and requirement of high energy for drying and conversion process. On the other hand the present invention process is safe, easy to handle, leachate free and completely free from foul odour and pathogens.
The present invention involves a process for converting municipal solid waste to solid fuel comprises the following steps:
1) Municipal solid waste is received from various places and segregation of the received waste is done incase of low moisture content (less than 20%) municipal solid waste.
2) Inoculum made from the naturally occurring strains of Lactobacillus and Saccharomyces is mixed with the collected municipal solid waste or to the segregated organic material by mass mixture or ribbon blender or any other equipment.
3) Heap or windrow of microbe mixed municipal solid waste is prepared and left for solid state fermentation to attain specific temperature and pH. This conditions leads to reduction of moisture in 8 – 15 days.
4) Once the moisture goes below 30%, municipal solid waste is fed to size segregation equipment.
5) Segregated municipal solid waste is subjected to mechanical equipment for removal of compost, stone, silt and any other material.

6) Oversize material from size segregation equipments are removed by means of manual or mechanical or pneumatic equipments.
7) Ferrous is separated by magnets and non-ferrous by eddy current.
8) The separated biomass is send to the pneumatic / mechanical equipments for cleaning to remove dirt, dust and other materials.
9) Shredding is done by shredding machine for getting specific sized refused derived fuel (RDF).
10)Refused derived fuel with specific size is further processed to form briquettes, pellets or fluff as per the market requirement. In the present invention 0.05-1% of microbial culture of Lactobacillus and Saccharomyces is taken and diluted with water having inoculum : water ratio 1:10 and after 16-24 hours foul odour control is controlled. 8-12 feet height heap or windrow is required to be prepared and it is kept under observation (i.e. for solid state fermentation) till it attains 50-80°C temperature and less than 7 pH. In the present invention selection of separation screen is depend upon the composition of the municipal solid waste. Biomass or MSW having 4-30 mm size is used to make solid fuel briquettes or pellets. Further, 0-4 mm sized MSW is used to make compost. Further shredded material having 20-50 mm size is used to make RDF (briquette or pellets or fluff).Removed stones are used to make concrete blocks. Further, Silt/dirt/dust, organic matter is reduced by mechanical or pneumatic equipment and utilized for making ‘Clay Bricks’.

The precondition for treatment is minimum moisture content of 35-40%. In case of waste having desired moisture, microbial treatment is done right after the collection of waste. In case of waste derived from ‘Segregation at Source’ systems, and then the waste having lower moisture content the treatment is applied to the organic and wet municipal solid waste after segregation. If moisture content is less than 35%, additional moisture is added by means of water. Also, method for the treatment of waste depends upon the types of the waste and moisture content of the collected waste material.
The invention is illustrated more in detail in the following example. The example describes and demonstrates embodiments within the scope of the present invention. This example is given solely for the purpose of illustration and is not to be construed as limitations of the present invention, as many variations thereof are possible without departing from the spirit and scope.
Example 1:
Composition of collected waste type I

Organic Compounds 37%
Metals 1.0%
Plastic materials 10%
Inert materials 15%
Moisture 37%
1. Municipal solid waste was received from the various places having composition as described above.

2. 0.06% solution of inoculum Lactobacillus and Saccharomyces were diluted in the water with the ratio of 1:10 and mixed with the collected municipal solid waste by mass mixture or ribbon blender.
3. 8 feet heighten heap of treated municipal solid waste was prepared and left for solid state fermentation till it attained over 50°C temperature, moisture less than 30% and pH of less than 7.
4. Waste from step (3) was fed to rotary screen for size separation of materials less than 100 mm size. Oversized materials were subjected to manual separation of organic matter, recyclable and non-recyclable material.
5. Waste of less than 100 mm size of step (4) was fed to rotary screen for separation of materials less than 25 mm size. Over 25 mm size material was fed to rotary screen of 75 mm and material under 25 mm size was fed to rotary screen of 4 mm.
6. Municipal solid waste over 75 mm size sent to separation, along with material over 100 mm separated municipal solid waste was further subjected to ferrous and nonferrous matter removal.
7. Material between 25 mm and 75 mm was subjected to mechanical or pneumatic or automatic sorter or similar thereof system for removal of stone, plastics, metal and/or similar thereof materials.
8. The shredded and separated MSW was sent to the pneumatic equipment or any other equipment for removal of dirt, dust and other unwanted materials.

9. Then, waste was fed to shredder for size reduction up to 25 mm
10. Cleaned MSW of 4-25 mm size was proceeded to make briquettes and pellets.
11. Cleaned briquettes, pellets and compost were packed in required mass and material.
Example 2:
Composition of collected waste type II

Organic Compounds 50%
Metals 15%
Plastic materials 15%
Paper 15%
Moisture 5%
1. Municipal solid waste was received from the various places having composition as described above.
2. Segregation of the waste was done to separate organic, recyclable and non-recyclable materials.
3. 1% solution of inoculum Lactobacillus and Saccharomyces were diluted in the water with the ratio of 1:10 and mixed with the segregated organic materials by mass mixture or ribbon blender or any other equipment.
4. Sufficient amount of water is added to raise the moisture content of 35% in organic matter.

5. 8 feet heighten heap of treated municipal solid waste was prepared and left for solid state fermentation till it attained over 50°C temperature and pH of less than 7.
6. Waste from step (5) was fed to rotary screen for size separation of materials less than 100 mm size.
7. Waste of less than 100 mm of step (6) was fed to rotary screen for separation of materials less than 25 mm size. Over 25 mm size material was fed to rotary screen of 75 mm and material under 25 mm size was fed to rotary screen of 4 mm.
8. Municipal solid waste over 75 mm size sent to - separation, along with material over 100 mm and separated municipal solid waste was further subjected to ferrous & non ferrous matter removal.
9. The shredded and separated biomass was sent to the pneumatic
conveyor or any other equipmentfor removal of dirt, dust and other unwanted materials. 10. Then, waste was fed to shredder for size reduction up to 25 mm.
11. Cleaned biomass of 4-25 mm size was proceeded to make briquettes and pellets.
12. Cleaned briquettes, pellets and compost were packed in required mass and material.
Comparative study analysis of different techniques has been done to check efficiency different technologies of composting methods.

Result:

Particulars Active Aerated Static In-Vessel Vermi Present
Windrow Windrow Channel composting Invention compositing
General Active systems Effective for farm Large-scale Low Effective for
most common and municipal solid systems for technology for farm and
on farms waste commercial medium size municipal solid
applications facility waste
Labour Increases with Requires trained Requires Labour Medium
aeration technical personnels trained intensive for labour of semi-
frequency and technical watering, skilled
poor planning personnels shifting & turning category
Water Medium Medium Low High Medium
requirement
Investment Medium High Very high Medium Medium
Energy Medium High Very high Low Medium
requirement
Segregation of Yes Yes Yes Yes No
waste
Leachate Yes Very less Yes Yes No
generation

Leachate Treatment Required Required Required Required Not required
Land Can require
large land
areas Less land required Very limited land Large with
composting
structure Less land required
Bulking Agent Flexible Less flexible, must be porous Flexible Less flexible,
limited feeds
allowed Flexible
Active Period Range: 21 - 40 days Range: 21 - 40 days Range: 21 - 35 days Range: 45 - 60 days Range: 15 - 30 days
Curing 30+ days 30+ days 30+ days Not applicable Not applicable
Size: Height 1 - 2.8 meters 3 - 4.5 meters Dependent on bay design Dependent on bin design. 2 - 4 meters
Size: Width 3 - 6 meters Variable Variable Dependent on bin design 2 - 4 meters
Size: Length Variable Variable Variable Variable Variable
Aeration System Mechanical turning and
natural convection Forced
positive/negative
airflow through pile Extensive
mechanical
turning and
aeration Manual turning Mechanical turning and
natural convection
Process Control Initial mix and turning Initial mix, aeration, temperature Initial mix,
aeration,
temperature Feed mix, turning, watering Initial mix and turning

Odour Factors
From surface Odour can occur, Odour can Odour can No odour after
area of but controls can be occur, Often occur, but 16-24 hours of
windrow used, such as pile due to generally for NPB Treatment
Turning can insulation and filters equipment first 30 days
create odours
during initial
weeks on air systems failure or
system design
limitations
Lossof C Yes, in case of Yes, in case of Yes, in case of Yes, in case of No, pH ranges
&N higher pH & higher pH & time higher pH & higher pH & between 5.5 -
time more more than 45 days time more time more 6.9 from 2nd
than 45 days than 45 days than 45 days day onward
Temperature Ambient to 700 Ambient to 700 C Ambient to 700 Ambient to 400 Ambient to 800
range C C C C
weed seed Partial Partial Partial Partial Yes, Control
control through
temperature
changes
Pathogen Partial Partial Partial Partial Yes, Control
control through pH &
temperature
changes
Table 1: Comparative study analysis of different technologies

Observation:
The present invention for solid state fermentation method is proved to be cost effective and eco-friendly as compare to other tedious methods with higher difficulties and more energy consumption as well as injurious to the environment.
While, the invention has been described with respect to the given embodiment, it will be appreciated that many variations, modifications and other applications of the invention may be made. However, it is to be expressly understood that such modifications and adaptations are within the scope of the present invention, as set forth in the following claims.

WE CLAIM,
1. A process for converting municipal solid waste (MSW) to solid fuel
comprises the following steps:
a) receiving municipal solid waste from various places;
b) mixing of diluted inoculums made from naturally occurring strains of Lactobacillus and Saccharomyces in received MSW;
c) preparing of heap or windrow and leaving the prepared heap or windrow for solid state fermentation;
d) feeding treated MSW on size segregation equipment;
e) separating treated MSW by mechanical equipment;
f) separating ferrous material by magnetic equipment and non ferrous material by eddy current from MSW;
g) cleaning the shredded MSW by pneumatic or mechanical equipment,
h) shredding treated MSW;
i) manually separating leather, cloths and plastic materials from the
MSW; j) molding and packaging into final product.
2. The process as claimed in claim 1 (b), wherein 0.05-1% inoculum of Lactobacillus and Saccharomyces is dilutedwith water by 1:10 inoculum : water ratio.
3. The process as claimed in claim 1 (c), wherein heap or windrow is kept for solid state fermentation till it reaches 50-80 °C temperature and less than 7 pH.
4. The process as claimed in claim 1 (e), wherein compost, stones, slit and other materials are removed during mechanical separation.

5. The process as claimed in claim 4, wherein concrete blocks are preparedfrom removedstones.
6. The process as claimed in claim 1 (g), wherein dirt, dust and other materials are removed during cleaning.
7. The process as claimed in claim 6, wherein clay bricks are made from removed dirt, dust and other organic materials.
8. The process as claimed in claim 1, wherein refused derived fuel is obtained by shredding.
9. The process as claimed in claim 1 (j), wherein the final product is briquettes, compost, pellets or fluff of solid fuel.
10. The process as claimed in claim 9, wherein final product is prepared on the size and character of the material.