Institute of hotel management & catering technology & applied nutrition

Research projectBy

Bineet Merrie Jan3rd year

Topic

Feasibility study on setting up of proper waste management system in the food

and beverage industry.

Roll no.: 060685

IGNOU Roll no.:063206499

Year: 2008- 2009

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RESEARCH PROJECTA Feasibility study on setting up of proper waste management system in food and beverage industry. This is a bonafied record of work done by Bineet Merrie Jan, Roll No. 060685. Submitted in partial fulfillment of the requirement for the Final Year Bachelor in Hotel Management and Catering Technology 2008- 2009.

Faculty Guide Research Coordinator Principal

SUBMITTED FOR THE VIVA VOICE EXAMINATION HELD ON ………………...

Internal Examiner External Examiner

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RESEARCH PROJECTA Feasibility study on setting up of proper waste management system in food and beverage industry. This is a bonafied record of work done by Bineet Merrie Jan, Roll No. 060685. Submitted in partial fulfillment of the requirement for the Final Year Bachelor in Hotel Management and Catering Technology 2008- 2009.

Faculty Guide Research Coordinator Principal

SUBMITTED FOR THE VIVA VOICE EXAMINATION HELD ON ………………...

Internal Examiner External Examiner

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AUTHENTICATION CERTIFICATE

I Bineet Merrie Jan, Hereby declare that this project is my original work and that I have not submitted this report to any university or academic institute for the partial fulfillment of any course or degree or diploma as the case may be.

Station: Chennai Student SignatureDate:

I certify that the above particulars are true and the project work has been done under my supervision.

Station: Chennai Guide SignatureDate:

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ACKNOWLEDGEMENT

I Bineet Merrie Jan, would like to acknowledge my

sincere thanks and gratitude to Mr. S Rajamohan,

Principal IHM Chennai, for the support extended by him

in completing this project.

I would also like to thank Mr. Jitendra Das, my project

guide and also project coordinator

Mr. Thriulogachandar, for all the assistance they offered,

which enabled me to complete this project. I also thank

them for the guidance they provided in finalizing project.

I cannot forget the valuable contributions the hospitality

students, educator respondents, and recruiters, made to

this project and I want to thank them for their

informative responses.

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CONTENTS

PROPOSAL FORMAT 06

DEFINING WASTE MANAGEMENT 09

WASTE MANAGEMENT CONCEPTS 10

WASTE DISPOSAL METHODS 12

HISTORY OF ANAEROBIC DECOMPOSITION 19

METHOD.

BIOGAS PLANT FOR BIOLOGICAL WASTES

RECYCLING 25

WHAT ARE THE BENEFITS OF BIOGAS PLANT? 28

BIOGAS PRODUCTION PROCESS 31

BIOGAS PLANT SCHEME 46

CONCLUSION 55

BIBLIOGRAPHY 56

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PROPOSAL FORMAT

NAME: Bineet merrie jan

COURSE/ YEAR, BATCH: Bsc. H&ha 3rd year, ‘A’ batch.

TITLE: Feasibility study on setting up of proper waste

management system in the food and beverage industry.

INTRODUCTION

Waste is an important by-product of the food and beverage

industry. Also it poses a great threat to the environment in which

we survive. Hence it is very much important to eradicate the

various threats that are caused by the pollution. At this present

century waste management is an important strategy that every

industry is looking forward to. Through my research project I

would like to bring out the various strategies that food and

beverage industry has taken to do a proper waste management.

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OBJECTIVES

To study about various waste management systems prevalent

in the industry.

To study about the various waste products that our industry

produce and its impact on the environment

To plan out a proper waste management system for the

industry.

Providing information about use of biogas production

technology in reducing the pollution.

METHODOLOGY

Information through various books and newspapers.

Information from Internet.

Information from various personalities working in the

industry.

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SCOPE OF STUDY

This research project is carried out in order to bring out an

awareness in the people regarding the need for proper

waste management system that has to be installed in the

food and beverage industry in order to reduce the

environment pollution that it causes.

It also provides an outline about the strategies that the

industry has to plan in order to have a self-sustainable

growth.

SIGNATURE OF THE STUDENT. GUIDE

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Defining Waste Management

Waste minimization is a methodology used to achieve waste

reduction, primarily through reduction at source, but also including

recycling and re-use of materials, as shown in the figure below.

The benefits of waste minimization are both environmental and

financial and wide in their coverage. Some of the main benefits

include the following:

Improved bottom line through improved process efficiency

Reduced burden on the environment, with improved public

image and compliance with legislation

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Better communication and involvement of employees and

therefore greater commitment to the business

Waste management concepts

There are a number of concepts about waste management, which

vary in their usage between countries or regions. Some of the most

general, widely used concepts include:

Diagram of the waste hierarchy.

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Waste hierarchy - The waste hierarchy refers to the "3 Rs"

reduce, reuse and recycle, which classify waste management

strategies according to their desirability in terms of waste

minimization. The waste hierarchy remains the cornerstone

of most waste minimization strategies. The aim of the waste

hierarchy is to extract the maximum practical benefits from

products and to generate the minimum amount of waste.

Extended producer responsibility - Extended Producer

Responsibility (EPR) is a strategy designed to promote the

integration of all costs associated with products throughout

their life cycle (including end-of-life disposal costs) into the

market price of the product. Extended producer responsibility

is meant to impose accountability over the entire lifecycle of

products and packaging introduced to the market. This means

that firms which manufacture, import and/or sell products are

required to be responsible for the products after their useful

life as well as during manufacture.

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Polluter pays principle - the Polluter Pays Principle is a

principle where the polluting party pays for the impact

caused to the environment. With respect to waste

management, this generally refers to the requirement for a

waste generator to pay for appropriate disposal of the waste.

Waste Disposal Methods

Source reduction

Volume of solid waste is reduced by reducing packaging,

disposable products, etc.

Could introduce advanced practices, reducing waste at source.

Many sources lie outside individual cities.

Uncontrolled dumping

Controlled application of waste on land.

Low-cost and low technology solution when land available. Risks

in certain circumstances, e.g., to water supply.

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Sanitary land filling

Controlled application of waste on land.

Low-cost and low technology solution when land available. Risks

in certain circumstances, e.g., to water supply.

Composting

Biological decomposition of organic matter in waste under

controlled conditions.

Needs correct proportion of biodegradable material in waste. May

be expensive where no market for compost. Large decentralized

schemes claimed to be unsuccessful.

Multi-material recycling

Complements composting Design products for ready

recycling/reuse, sorting by consumers and pick-up by types of

materials.

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Recycling and reuse already occurs in many countries as a matter

of economic necessity.

Incineration

Controlled burning of waste at high temperatures to reduce its

volume; possibility to gain energy from combustion.

High capital cost; requires skilled operation and control. Waste

must have high calorific value. Advantage if land not available for

landfill.

Gasification

Biological decomposition of organic matter in waste under

controlled conditions to obtain methane and other gases.

High cost and technologically complicated.

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Refuse derived fuel

Separation of combustible materials from solid waste to be used

for fuel purposes.

Assumes combustible material not separated out. Costs and

operational issues not widely known for large-scale operations.

Pyrolysis

High temperature conversion of organic material in absence of

oxygen to obtain combustible by-products.

Capital intensive with high running costs, and technically complex.

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Advantages and Disadvantages

OCEAN DUMPING

Advantages:

Convenient

Inexpensive

Source of nutrients, shelter and breeding

Disadvantages:

Ocean overburdened

Destruction of food sources

Killing of plankton

Desalination

SANITARY LANDFILL

Advantages:

Volume can increase with little addition of people/equipment

Filled land can be reused for other community purposes

Disadvantages:

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Completed landfill areas can settle and requires maintenance

Requires proper planning, design, and operation

INCINERATION

Advantages:

Requires minimum land

Can be operated in any weather

Produces stable odor-free residue

Refuse volume is reduced by half

Disadvantages:

Expensive to build and operate

High energy requirement

Requires skilled personnel and continuous maintenance

Unsightly - smell, waste, vermin

OPEN DUMPING

Advantages:

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Inexpensive

Disadvantages:

Health-hazard - insects, rodents etc.

Damage due to air pollution

Ground water and run-off pollution

RECYCLING

Advantages:

Key to providing a livable environment for the future

Disadvantages:

Expensive

Some wastes cannot be recycled

Technological push needed

Separation of useful material from waste difficult

History of anaerobic decomposition method.

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Scientific interest in the gasses produced by the natural

decomposition of organic matter, was first reported in the

seventeenth century by Robert Boyle and Stephen Hale, who noted

that flammable gas was released by disturbing the sediment of

streams and lakes. In 1808, Sir Humphry Davy determined that

methane was present in the gasses produced by cattle manure. The

first anaerobic digester was built by a leper colony in Bombay,

India in 1859. In 1895 the technology was developed in Exeter,

England, where a septic tank was used to generate gas for street

lighting. Also in England, in 1904, the first dual purpose tank for

both sedimentation and sludge treatment was installed in Hampton.

In 1907, in Germany, a patent was issued for the Imhoff tank, an

early form of digester.

Through scientific research anaerobic digestion gained academic

recognition in the 1930s. This research led to the discovery of

anaerobic bacteria, the microorganisms that facilitate the process.

Further research was carried out to investigate the conditions under

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which methanogenic bacteria were able to grow and reproduce.

This work was developed during World War II where in both

Germany and France there was an increase in the application of

anaerobic digestion for the treatment of manure.

Applications

Anaerobic digestion is particularly suited to wet organic material

and is commonly used for effluent and sewage treatment.

Anaerobic digestion is a simple process that can greatly reduce the

amount of organic matter, which might otherwise be destined to be

land filled or burnt in an incinerator.

Almost any organic material can be processed with anaerobic

digestion. This includes biodegradable waste materials such as

waste paper, grass clippings, leftover food, sewage and animal

waste. The exception to this is woody wastes that are largely

unaffected by digestion as most anaerobes are unable to degrade

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lignin. The exception being xylophalgeous anaerobes (lignin

consumers), as used in the process for organic breakdown of

cellulosic material by a cellulosic ethanol start-up company in the

U.S. Anaerobic digesters can also be fed with specially grown

energy crops such as silage for dedicated biogas production. In

Germany and continental Europe these facilities are referred to as

biogas plants. A co-digestion or co-fermentation plant is typically

an agricultural anaerobic digester that accepts two or more input

materials for simultaneous digestion.

In developing countries simple home and farm-based anaerobic

digestion systems offer the potential for cheap, low-cost energy for

cooking and lighting. The United Nations Development

Programme has recognized anaerobic digestion facilities as one of

the most useful decentralized sources of energy supply. From

1975, China and India have both had large government-backed

schemes for adaptation of small biogas plants for use in the

household for cooking and lighting. Presently, projects for

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anaerobic digestion in the developing world can gain financial

support through the United Nations Clean Development

Mechanism if they are able to show they provide reduced carbon

emissions.

Pressure from environmentally related legislation on solid waste

disposal methods in developed countries has increased the

application of anaerobic digestion as a process for reducing waste

volumes and generating useful by-products. Anaerobic digestion

may either be used to process the source separated fraction of

municipal waste, or alternatively combined with mechanical

sorting systems, to process residual mixed municipal waste. These

facilities are called mechanical biological treatment plants.

Utilizing anaerobic digestion technologies can help to reduce the

emission of greenhouse gasses in a number of key ways:

Replacement of fossil fuels

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Reducing methane emission from landfills

Displacing industrially-produced chemical fertilizers

Reducing vehicle movements

Reducing electrical grid transportation losses

Methane and power produced in anaerobic digestion facilities can

be utilized to replace energy derived from fossil fuels, and hence

reduce emissions of greenhouse gasses. This is due to the fact that

the carbon in biodegradable material is part of a carbon cycle. The

carbon released into the atmosphere from the combustion of biogas

has been removed by plants in order for them to grow in the recent

past. This can have occurred within the last decade, but more

typically within the last growing season. If the plants are re-grown,

taking the carbon out of the atmosphere once more, the system will

be carbon neutral. This contrasts to carbon in fossil fuels that has

been sequestered in the earth for many millions of years, the

combustion of which increases the overall levels of carbon dioxide

in the atmosphere.

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If the putrescible waste processed in anaerobic digesters were

disposed of in a landfill, it would break down naturally and often

anaerobically. In this case the gas will eventually escape into the

atmosphere. As methane is about twenty times more potent as a

greenhouse gas as carbon dioxide this has significant negative

environmental effects.

Digestate liquor can be used as a fertilizer supplying vital nutrients

to soils. The solid, fibrous component of digestate can be used as a

soil conditioner. The liquor can be used as a substitute for chemical

fertilizers, which require large amounts of energy to produce. The

use of manufactured fertilizers is therefore more carbon intensive

than the use of anaerobic digestate fertilizer. This solid digestate

can be used to boost the organic content of soils. There are some

countries, such as Spain where there are many organically depleted

soils, and here the markets for the digestate can be just as

important as the biogas.

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In countries that collect household waste, the utilization of local

anaerobic digestion facilities can help to reduce the amount of

waste that requires transportation to centralized landfill sites or

incineration facilities. This reduced burden on transportation has

and will reduce carbon emissions from the collection vehicles. If

localized anaerobic digestion facilities are embedded within an

electrical distribution network, they can help reduce the electrical

losses that are associated with transporting electricity over a

national grid.

Biogas plant for biological wastes recycling

What is biogas plant?

Biogas plant produces biogas and bio-fertilizer from biological

wastes of agricultural and food industries by means of oxygen-free

fermentation (anaerobic digestion).

Biogas plant – is the most active system of biological recycling.

This system performs utilization, recycling and has shortest

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payback period. The differences from the other recycling systems

are the following.

1) biogas plant does not consumes power, but produces it

2) produced electricity is used by the enterprise and end products

of other recycling systems (dry feed or dry manure) needs to be

sold or recycled.

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Following raw materials can be used for biogas

production:

Cattle manure, pig manure, chicken dung, slaughterhouse waste

(blood, fat, entrails, and rumen content), plants waste, silage, rotten

grain, waste water, fats, bio-waste, food industry waste, malt

remnants, marc, distillery slop, bioethanol plant slop, brewer’s

grain (crushed malt remnants after wort filtration), sugar beet and

fruit pulp, sugar beet tops, technical glycerin (after biodisel

production), fiber and other starch and treacle production, milk

whey, flotation sludge, dewatered flotation sludge from municipal

waste water treatment plants, algae. Most of the raw materials can

be mixed with each other.

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What are the benefits of biogas plant?

Waste recycling gives:

Main benefits

1. Ecological cleaning

2. Gas,

3. Bio-fertilizer,

4. Investment cost saving (for new enterprises)

Additional benefits

1. Electricity,

2. Heat,

\

Ecological cleaning and utilization

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Biogas plant can reduce sanitary zone (distance from the enterprise

to residential area) from 500m to 150m. In many cases such

ecological issues are vital for some enterprises.

Out-of-date lagoons occupy lots of space and have bad smell.

Biogas plant requires space that several times less if to be

compared to lagoons and manure storages. Water in lagoons is

bounded by colloid compounds hence evaporation is very faint.

After treatment in biogas plant water is separated and easily

vaporized. Digested biomass can be released to the fields without

any time delays, which can reduce lagoons area up to 5 times!

Investments into lagoon construction are money thrown down the

drain. By investing into biogas plant you payback your money with

profit and make land usage more effective. Biogas plant

construction is useful not only for new farms but for existing as

well, because old lagoons maintenance cost are considerable.

Some of waste products can be stored in lagoons while the other

requires energy and cost consuming utilization (slaughterhouse

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waste), biogas production looks more attractive in that respect.

Usage of conventional lagoons and land fills often makes possible

filtrate percolation to the groundwater that causes health problems

to people and animals as well as sanctions from state sanitary

service and costly medical treatment. Using biogas plant system

you will avoid diseases, medical and penalty bills.

Equipped with additional filtration devices (pressure filter,

decanter) biogas plant can reduce COD and BOD levels in filtrate

so it can be discharged to sewage system or factory water

treatment facility. COD – chemical oxygen demand and BOD –

biological oxygen demand. Biogas plant makes possible removal

of most part of contaminating biological matter (organic matter

content reduced up to 60-70%).

Biogas production process

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Four steps of fermentation

Scheme 1. Metabolism products of the anaerobic fermentation

Bacteria decompose the organic matter in anaerobic environment.

Biogas is an intermediate product of their metabolism.

The decomposition process can be divided into 4 steps (see scheme 1)

each of those accompanied by different bacteria groups:

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In the first stage aerobic bacteria reconstructs high-molecular

substances (protein, carbohydrates, fats, cellulose) by means of

enzymes to low-molecular compounds like monosaccharide, amino

acids, fatty acids and water. Enzymes assigned by hydrolysis bacteria

decompose substrate components to small water-soluble molecules.

Polymers turn into monomers (separate molecules). This process

called hydrolysis.

Then acid-forming bacteria make decomposition. Separate molecules

penetrate into bacteria cells where further transformation takes place.

This process is partially accompanied by anaerobic bacteria that

consume rest of oxygen hence providing suitable anaerobic

environment for methane bacteria.

This step produces:

Acids (acetic acid, formic acid, butyric acid, propionic acid,

caproic acid, lactic acid),

Alcohols and ketones (methanol, ethanol, propanol, butanol,

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glycerin and acetone),

Gases (carbon dioxide, carbon, hydrogen sulfide and ammonia).

The step is called oxidation.

Afterwards acid-forming bacteria form initial products for methane

formation: acetic acid, carbon dioxide and hydrogen). These products

are formed from organic acids. For vital functions of these bacteria

that consume hydrogen, stable temperature mode is very important.

The last step is methane, carbon dioxide and water formation.

90% of methane yield takes place at this stage, 70% from acetic acid.

Thus acetic acid formation (3rd step) is the factor that defines the

speed of methane formation.

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One and two stages process

Scheme 2. One and two stages methane production process.

 

In most cases such processes take place simultaneously it means that

there is no boundaries for place and duration of decomposition. Such

technology is called two stages technology. For fermentation of

rapidly decomposable raw materials in pure state two stage

technology required. For example chicken dung, distillery slop

shouldn’t be recycled in one digester. In order to process those

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substrates hydrolysis reactor is needed. Such reactor allows control

over the acidity and alkalinity level in order to avoid bacteria collapse

and increase methane yield. (Scheme 2.)

For successful lifecycle of all microorganisms inside the digester

special conditions must be secured. Mandatory factors for that are the

following:

Anaerobic environment - active functioning of bacteria is possible

only in oxygen-free conditions.

Biogas plant design takes that into consideration.

Humidity - bacteria can live, feed and propagate only in moist

conditions.

Temperature - the optimum temperature for mode for all bacteria

groups is 35-40о С range. Human is not able to control this, that is

why it is done by automatic control system.

Fermentation period - The quantity of produced biogas is different

within the fermentation period. In the beginning of fermentation it is

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more intensive then at the en of it. Then comes the moment when

further biomass presence in the digester is economically unfeasible.

Our specialists rest upon long-term experience while calculating

fermentation period efficiency.

 

рН level - hydrolysis and oxidation bacteria can live in acid

environment with pH level 4.5-6.3 while methane and acetic acid

formation bacteria can exist only in low alkalinity environment with

pH 6.8-8. All the bacteria kinds have tendency to suspend their

activity in case pH level is higher of the optimum hence the biogas

production suspends as well. That is why the best pH level 7 should

be maintained.

Even substrate feed - the by-products of each group of bacteria

lifecycle are the nutrients for other bacteria group. The all work with

different speed. The bacteria should not be overfeed as they hardly be

able to produce nutrients for another group. That is why the substrate

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feed is calculated and programmed for each project carefully.

Nutrients supply - bacteria provided with all necessary nutrients that

are contained in substrate so the only thing is needed is constant

substrate supply. Substrate contains vitamins, soluble ammonia

compounds, microelements and heavy metals in small quantities.

Nickel, cobalt, molybdenum, wolfram and ferrum are required by

bacteria for enzyme formation and are also present in substrates.

Particle size - The smaller the better rule is working here. Bacteria

size 1/1000 mm the smaller the substrate particles the easier the

decomposition made by bacteria. Fermentation period becomes

shorter and biogas production faster. If necessary additional substrate

disintegration should be done before substrate feed into reactor.

Mixing - is important not only to avoid floating cork and sediment

formation but also for biogas extraction (mixers help bubbles to go up

the digester). Mixers work constantly in a bacteria preserving mode.

Process stability - microorganisms are used to certain feed other

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modes.

Any changes should be done smoothly.

Avoid getting into reactor antibiotics, chemical and disinfection

means, big quantities of heavy metals. Our specialists can advice you

on that.

The end product of biological treatment are:

biogas (methane not less then 55%, carbon dioxide not more

then 45%, hydrogen sulfide not more then 2%, hydrogen not

more then 1%);

fermented substrate as fermentation residue, consisting of

water, cellulose residues, small quantity of bacteria and organic

nutrients (nitrogen, phosphorus, potassium etc.).

Biogas

What is biogas?

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Biogas is the gas consisting of approximately 50-70% of methane

(CH4) and 50-30% of carbon dioxide (CO2). Synonyms for biogas

such words as sewage gas, marsh gas, methane. Different

microorganisms metabolizing carbon from organic matter in

oxygen-free environment (anaerobically). This process is known as

decomposition or anoxic fermentation and follows food chain. In

the process of fermentation biological waste produces biogas. This

gas can be used as natural gas for technological purposes, heating

or electricity production. It can be stored, pumped, used as vehicle

fuel or sold to your neighbors. In order to produce electricity no

additional treatment of biogas is required.

By properties biogas is similar to natural gas. In case adjustable

burner is used biogas needs only drying, hydrogen sulfide and

ammonia removal. If the burner is not adjustable the system of

carbon dioxide removal will be needed.

For vehicle refueling additional gas treatment system should be

used. After such treatment biogas becomes pure natural gas analog

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(90-97% of methane (CH4) and 10-3% of carbon dioxide (CO2)).

Another by-product of biogas treatment is CO2. This gas used as dry ice,

for beverages production or technological purposes and can be sold as valuable

commodity.

Raw materialBiogas yield m3/t of raw

material

Cow manure 60

Pig manure 65

Chicken dung 130

Fat 1300

Distillery slop 70

Grain 500-560

Silage, plant tops,

grass, algae400

Milk whey 50

Fruit and sugar beet 50-70

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pulp

Technical glycerin 500

Brewer’s grains 180

Anyone understands that natural gas price increase is inevitable

and substantial. Gas pipeline broaching worth millions of dollars,

contrarily biogas plants construction is more cost effective. After

investment into gas pipeline we have to pay for gas as well, to be

compared with biogas it is nearly costless (less then 30 123 per

1000 m3). Biogas plant is the best solution for gas supply to

remote regions.

Bio-fertilizer

Raw manure or other biological waste is not applicable as fertilizer

for 3-5 years. Anaerobically digested biomass is a finished and

ready for use high-performance bio-fertilizer. This is not only

ecological issue, but the matter of profit. In raw biological waste

(manure for example) minerals are chemically bounded to organics

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that complicates their consumption by plants. For example

mineralization in raw manure is 40% if to be compared to 60% in

digested biomass. Digested biomass is finished solid and liquid

bio-fertilizer free of nitrites, weed seeds, pathogenic microflora,

helminth eggs and odors. As a result of balanced bio-fertilizer

application crop yield can be increased up to 30-50%.

Biogas plant produces high quality bio-fertilizer. Bio-fertilizer is a

commodity. The quality of bio-fertilizer is higher then mineral

fertilizers and the net cost almost equals to “0”. As a commodity it

can be sold to anyone.

Investment savings

New enterprises can have considerable investment savings due to

the possibility to avoid building new gas pipeline, electricity line,

auxiliary generators and waste storage facilities. Thanks to the

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short digestion period the volume of waste lagoons can be reduced

twice. Investment cost savings can reach about 30-40% from

biogas plant price.

Electricity

Combustion of 1 m3 produces 2 kWh of electricity. You get

fluctuation free electricity in comparison with public electricity

network. By building biogas plant you will have electricity at a

fixed price, that makes about 0.01$/kWh.

Heat

Heat from generator cooling or biogas combustion is used for

working premises heating, technological purposes, steam

generation, seeds drying, firewood drying, hot water supply and

stock keeping.

New or existing greenhouse nearby biogas plant is a perfect

solution. Heat can come directly from biogas combustion or from

generator cooling device. Only generator cooling device can heat 2

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Ha of greenhouse area. 90% of expenses for growing greenhouse

cucumbers, tomatoes and flowers are heat and fertilizer costs. If

greenhouse combined with biogas plant it is possible to reach 300-

500% of profitability.

Heat is also used to activate refrigerator vaporizer and produce

cold for refrigeration of fresh milk at dairy farms or meat and eggs

storage.

Vehicle fuel

After treatment of biogas you get biomethane (90-95% methane,

the rest is CO2). Biomethane is complete analog of natural gas by

its properties and quality. The only difference is the source of the

gas. Such methane can be and should be filled into vehicle tank.

Huge gas filling station network already exists. In the

circumstances of constant diesel fuel rice in price, methane usage

becomes more attractive. Biogas plants equipped with biogas

treatment system and methane filling station. Also we can

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undertake conversion of engines to run on methane. Conversion of

one system unit to run on methane costs 2200 123, all materials

and work included. Methane filling station payback period is about

half a year.

Net cost of biomethane is 1200 Rs for 1000 m3, and price for diesel

fuel 50000 Rs for 1000 L.  1 L of diesel fuel equals 1 m3 of

biomethane.

 

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Biogas plant scheme

Operation principle of biogas plant

Liquid biological waste is pumped to biogas plant by sanitary

pump or extraction pipeline. Sewage pumping station (SPS) is

located in a separate service room. Solid biological waste (manure,

dung) delivered by belt conveyor, in case of manure or dung

storage, delivery made by tractor. Liquid wastes initially come to

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primary tank. In primary tank waste homogenized and heated

(sometimes cooled) for required temperature. As a rule such tank

has 2-3 days storage capacity. Solid waste can be loaded to that

tank as well for homogenization or get into digester through screw

charger.

From homogenization tank and screw charger biomass (manure,

dung or distillery slop) comes to digester (biological reactor).

Biological reactor is gas-proof tank made of acid-resistant

concrete. Reactor is heat-insulated. The heat-insulation is

calculated depending on the biogas plant site climate conditions.

For microorganisms’ vital activity a constant and even temperature

inside the digester is kept, usually it is mesophilic temperature

mode (+30-41°С). In some cases termophilic mode of temperature

is used (about 55°С). Biomass mixing inside the digester is made

by several ways and depends on the type of raw material, its

humidity and other features. Mixing can be done by slopped mixer,

“paddle giant” type mixer or submersed mixers. Al mixer types are

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made of stainless steel. In some cases mixing device can be

hydraulic instead of mechanical. Such mixers pump the biomass

into the layers with bacterial clumps. Bioreactors are built with

wooden or concrete dome and have service life of 25-30 years.

Digesters are heated by hot water with inlet temperature about

60°С and discharge temperature of about 40°С. Heating system is

a network of pipes, which can be built-in to reactor wall or to be

mounted to interior side of the digester wall. In case biogas plant

equipped with co-generation unit, digester can be heated by

generator cooling water. Generator cooling water has temperature

of 90°С and before getting into digester heating system it is mixed

with 40°С water so that heating system receives water with 60°С.

The water is previously treated and returnable. In winter time

biogas plant requires up to 70% of heat from generator cooling

device and 10% in summer time. If biogas plant is purposed only

for gas production hot water is taken from a special water boiler.

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Biogas plant self energy and heat consumption usually makes from

5% to 15% of overall produced.

The average hydraulic retention time of biomass in bioreactor

(depending on the material type) is 20-40 days. During this time

organic matter is metabolized (modified) by microorganisms

presented in the biomass. Corn silage hydraulic retention time is

about 70-160 days. The hydraulic retention time defines the size of

the digester.

The fermentation process is made by anaerobic microorganisms,

which are injected into the digester during the biogas plant start up.

Any further microorganisms injection is not required.

Microorganisms injection is made by one of three ways: 1)

microorganisms concentrate injection 2) fresh manure addition or

3) injection of biomass from operational biogas plant. As a rule

2nd and 3rd methods are used being cheapest ones.

Microorganisms get into manure from animal bowels and are not

harmful to human or animal. Moreover bioreactor is a hermetically

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sealed container. That is why bioreactors or fermenters can be

placed near the farm or production facilities.

As end products we have: biogas and bio-fertilizer (composted or

liquid).

Biogas is stored at a gasholder. Inside the gasholder pressure and

biogas composition is evened. Gasholder is a high-tensile and

distensible EPDM membrane. The membrane material is resistant

to sunlight and internal bioreactor sediments and evaporations.

Gasholder service lifetime is 15 years. Bioreactor hermetically

sealed by the gasholder from the topside and covered by additional

tilt cover. The space between the gasholder and tilt cover is

pumped with an air in order to form pressure and heat insulation.

Sometimes gasholder is a multichamber cover. Depending on the

project solution such cover can be secured by belts on the top of

the concrete dome or to be placed in a separate concrete tank.

Gasholder volume capacity is 0.5 – 1 operational day.

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From the gasholder biogas constantly comes to gas or diesel/gas

co-generation unit. Here heat and electricity are being produced.

1m3 of biogas produces 2 kWh of electrical and 2 kWh of heat

power. Big biogas plants are equipped with an emergency flare for

instances of engines malfunction and the necessity to burn the

excessive biogas. Biogas system can be equipped with ventilation,

condensate extractor and desulphurization unit.

The automatic control unit operates the whole system. Control unit

operates the work of pumping station, mixers, heating system, gas

automatics and generator. For operational control only one person

for 2 hours a day is required. This person affects the control with

the help of computer. After two weeks of training any person

without any special skills can operate the biogas plant.

Anaerobically digested biomass is finished and ready for use as

fertilizer. Liquid bio-fertilizer is separated by separation unit and

stored in a tank. In Germany this liquid (ammonia water) is used as

a fertilizer due to high ammonia (NH4) content. Solid fertilizer is

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stored separately. From the storage tank liquid bio-fertilizer is

pumped to transportation tanks for further distribution or sale. As

an option biogas plant can be supplied with fertilizer packing line

(bottles 0.3, 0.5, 1.0 l). In case liquid fertilizer is of no interest for

biogas plant owner, such plant can be equipped with additional

wastewater treatment modules.

When company doesn’t need electricity but gas for vehicle filling,

biogas plant supplied with gas treatment system and methane

filling station. Gas treatment system is equipment that separates

carbon dioxide from biogas and is based on absorption and stripper

technology. Carbon dioxide content can be reduced from 40% up

to 10% (even 1% is possible if required). This option is very

interesting taking into consideration diesel fuel high prices.

For some types of biological waste above mentioned operation

principle requires modification. For example it is not workable

with single raw materials such as distillery slop and brewer’s grain.

In that instance two stage systems with additional hydrolysis

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reactor should be used. The peculiarity of the process is the support

of acidity level in hydrolysis reactors. This technology patented by

123 and is under protection that makes impossible it’s usage by

other companies.

Biogas plant self energy consumption is 10-15% in wintertime and

3-7% in summer time. In order to operate even big biogas plant

only one person for two hours a day required.

Biogas plant equipment and facilities

1. Homogenization tank

2. Solid biomass loader

3. Bioreactor (digester)

4. Mixing devices

5. Gasholder (gas storage)

6. Water mixing and heating system

7. Gas system

8. Pumping station

9. Separator

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10. Control gauges

11. Control equipment with visualization

12. Emergency flare system and security system

CONCLUSION

Thus it can be concluded that waste management is an

important part in outlining the developmental strategies

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of every industry especially in the food and beverage

industry.

Now a days since the environmental laws are really

strict it becomes the need of the hour to plan and

execute the various waste management programmes

that are necessary for the industry.

BIBLIOGRAPHY

The Hindu Daily.

Hotel and Hospitality Magazines

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Wikipedia.org

Gdrc.org

Zorg-biogas.com

Wm.com

Auroville.com

Ficci.com

BOOKS

Journal of industrial Ecology, S. Nakamura. 2002.

International Journal Of Contemporary

Hospitality Management, D. Krik- 1995

Waste Management And Reserch,Y. S Wang-1997

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