comparative economical analysis of biogas …

MSc ProgramRenewable Energy in Central and Eastern Europe

A Master’s Thesis submitted for the degree of“Master of Science”

supervised by

COMPARATIVE ECONOMICAL ANALYSIS OF BIOGASPRODUCTION COSTS BETWEEN STANDARD

WET ANAEROBIC DIGESTION AND DRYFERMENTATION OF BIODEGRADBLE FRACTION OF

MUNICIPAL SOLID WASTE

Univ.Prof.Dr. Haas Reinhard

Vladimir-Miša Kova evi

9230117

Vienna, 30.09.2010

Die approbierte Originalversion dieser Diplom-/Masterarbeit ist an der Hauptbibliothek der Technischen Universität Wien aufgestellt (http://www.ub.tuwien.ac.at). The approved original version of this diploma or master thesis is available at the main library of the Vienna University of Technology (http://www.ub.tuwien.ac.at/englweb/).

i

Affidavit

I, Dipl.-Ing. Vladimir-Misa Kovacevic, hereby declare

1. that I am the sole author of the present Master‘s Thesis, "COMPARATIVE

ECONOMICAL ANALYSIS OF BIOGAS PRODUCTION COSTS

BETWEEN STANDARD WET ANAEROBIC DIGESTION AND DRY

FERMENTATION OF BIODEGRADABLE FRACTION OF MUNICIPAL

SOLID WASTE”, 65 pages, bound, and that I have not used any source or tool

other than those referenced or any other illicit aid or tool, and

2. that I have not prior to this date submitted this Master’s Thesis as an

examination paper in any form in Austria or abroad.

Vienna, 30.09.2010 ___________________________

Signature

ii

Abstract

Anaerobic biological treatment of biodegradable fraction of municipal solid waste

has the opportunity to be an integral part of the solution to two of the most pressing

environmental concerns of urban regions: waste management and renewable energy.

Anaerobic digestion AD is a well-known biological treatment process of

biodegradable fraction of municipal solid waste with an aim to produce biogas and in

that way generate electricity. When speaking about anaerobic digestion we mostly

refer to the so-called “wet” processes with total solids (TS) percentage between 15

and 25%. The biggest cost of the anaerobic digestion relates to treatment of percolate

water produced during the AD process and increased investment in the AD plants

because of the need for additional pre- and post treatment of biodegradable fraction

of municipal solid waste.

A few years ago, a new technology appeared on the market called Dry Fermentation

(DF) as an alternative to anaerobic digestion. In the Dry Fermentation process total

solids (TS) percentage is bigger than 50% which drastically decreases the amount of

percolate water necessary to manage and treat subsequently.

On the other hand, anaerobic digestion (AD) produces larger quantity of biogas

(electricity), and in addition anaerobic digestion (AD) plants are more suitable for

larger capacities of input waste material and they occupy less space.

This thesis examines in depth differences between “wet” Anaerobic Digestion and

Dry Fermentation and provides economical evaluation and comparison of two

processes by taking into account most important advantages and disadvantages of

both processes. It also gives precise information about influence of disposal cost and

sale electrical energy tariff on the profitability of both type of technological plants.

iii

Contents

Affidavit ........................................................................................................................ i

Abstract ........................................................................................................................ ii

Contents ...................................................................................................................... iii

Tables ........................................................................................................................... v

Figures ......................................................................................................................... vi

Abbreviations ............................................................................................................. vii

1. Introduction and purpose of the work ................................................................... 1

1.1 Motivation of this study ................................................................................ 1

1.2 Core question ................................................................................................. 2

1.3 Method of approach ....................................................................................... 2

1.4 The structure of the work .............................................................................. 2

1.5 Citation of main literature ............................................................................. 3

2. Anaerobic biological treatment of municipal solid waste .................................... 4

2.1 Definition of the Municipal Solid Waste....................................................... 4

2.2 Biochemical Reactions .................................................................................. 5

2.3 Products of anaerobic biological treatment ................................................... 7

2.3.1 Biogas ..................................................................................................... 7

2.3.2 Digestate ................................................................................................. 9

2.4 General advantages of anaerobic biological treatment ................................ 10

3. Anaerobic Digestion technology overview......................................................... 11

3.1 Process description ...................................................................................... 11

3.1.1 Pre-Treatment ....................................................................................... 11

3.1.2 Digestion .............................................................................................. 12

3.1.3 Post Treatment of digestate form AD .................................................. 14

3.2 Conditions and variables influencing AD ................................................... 17

3.2.1 Total Solid Content .............................................................................. 17

3.2.2 Temperature ......................................................................................... 17

3.2.3 Retention time ...................................................................................... 18

3.2.4 pH ......................................................................................................... 18

3.2.5 Carbon to Nitrogen ratio (C/N) ............................................................ 18

iv

3.2.6 Mixing .................................................................................................. 19

3.2.7 Organic Loading Rate/Volatile Solids ................................................. 19

4. Dry Fermentation technology overview ............................................................. 20

4.1 Process description ...................................................................................... 20

4.1.1 Pre-Treatment ....................................................................................... 22

4.1.2 Fermenters ............................................................................................ 22

4.1.3 Process monitoring and control ............................................................ 22

4.1.4 Heat and Power Generation ................................................................. 23

5. Basic key assumptions for financial analysis ..................................................... 24

5.1 Technical and Financial assumptions .......................................................... 24

5.2 Total costs calculation ................................................................................. 25

5.3 Calculation of Investment costs .................................................................. 25

5.3.1 Building Works costs and Electro – Mechanical Works costs for AD 26

5.3.2 Building Works costs and Electro – Mechanical Works costs for DF . 27

5.4 Calculation of Amortisation and Financing costs ....................................... 28

5.5 Calculation of Operating and Maintenance costs ........................................ 28

5.6 Disposal costs .............................................................................................. 28

5.7 Corporate earnings ...................................................................................... 29

5.8 Revenues ..................................................................................................... 29

5.9 Gate Fee calculation .................................................................................... 29

6. Technical and Economic Aspects of Anaerobic Digestion ................................ 30

7. Technical and Economic Aspects of Dry Fermentation ..................................... 37

8. Economic Comparison of Anaerobic Digestion and Dry Fermentation ............. 43

8.1 Economic comparison of the Investment and O&M Costs ......................... 44

8.2 Economic comparison of the Gate Fee ........................................................ 47

9. Conclusions and recommendations .................................................................... 53

9.1 Conclusions ................................................................................................. 53

9.2 Recommendations ....................................................................................... 54

References .................................................................................................................. 56

Annex 1 ...................................................................................................................... 57

v

Tables

Table 2.1 Typical structure of the MSW

Table 2.2 Typical composition of biogas

Table 2.3 – Benefits from anaerobic biological treatment

Table 6.1 Economic analysis of AD at different scales

Table 6.2 Total Disposal Costs in correlation with waste water disposal costs AD

Table 6.3 Total Costs in correlation with waste water disposal costs AD

Table 6.4 Total Revenues in correlation with Sale Energy Tariffs AD

Table 7.1 Economic analysis of DF at different scales

Table 7.2 Total Disposal Costs in correlation with waste water disposal costs DF

Table 7.3 Total Costs in correlation with waste water disposal costs DF

Table 7.4 Total Revenues in correlation with Sale Energy Tariffs DF

Table 8.1 Comparison of Gate Fee for Sale Energy tariff of 0,09 €/kWh



Table 10.1 Building Works costs calculation

Table 10.2 Electro-mechanical costs calculation

Table 10.3 Amortisation and financing costs calculation

Table 10.4 O & M summary costs calculation

Table 10.5 El. Energy costs calculation

Table 10.6 Personal costs calculation Anaerobic Digestion

Table 10.7 Personal costs calculation Dry Fermentation

Table 10.8 Maintenance costs calculation

Table 10.9 Mobile Vehicle costs calculation Anaerobic Digestion

Table 10.10 Mobile Vehicle costs calculation Dry Fermentation

vi

Figures

Figure 2.1 The Four Phases of Anaerobic Process

Figure 2.2 The Four Phases of Anaerobic Process

Figure 3.1 The General process for an AD plant

Figure 3.2 Classification of AD by operational criteria

Figure 4.1 The General process for an Dry Fermentation plant

Figure 6.1 Total investment costs AD

Figure 6.2 Unit investment costs AD

Figure 6.3 Specific unit investment costs for biogas production AD

Figure 6.4 Specific unit investment costs for electricity production AD

Figure 6.5 Mass balance flow diagram of Anaerobic Digestion

Figure 6.6 Total Disposal Costs of AD in correlation with waste water disposal costs

Figure 6.7 Total Costs of AD in correlation with waste water disposal costs

Figure 6.8 Total Revenues in correlation with Sale Energy Tariffs

Figure 7.1 Total investment costs DF

Figure 7.2 Unit investment costs DF

Figure 7.3 Specific unit investment costs for biogas production

Figure 7.4 Specific unit investment costs for electricity production

Figure 7.5 Mass balance flow diagram of Dry Fermentation

Figure 7.6 Total Disposal Costs of DF in correlation with waste water disposal costs

Figure 7.7 Total Costs of DF in correlation with waste water disposal costs

Figure 7.8 Total Revenues in correlation with Sale Energy Tariffs DF

Figure 8.1 Comparison of Total Investment Costs

Figure 8.2 Comparison of Unit Investment Costs

Figure 8.3 Comparison of O&M Costs

Figure 8.4 Comparison of Specific Investment Costs for biogas production

Figure 8.5 Comparison of Specific Investment Costs for electrical energy production

Figure 8.6 Comparison of Gate Fee for Sale Energy tariff of 0,09 €/kWh



vii

Abbreviations

AD Anaerobic Digestion

CHP Combined Heat and Power

COD Chemical Oxygen Demand

C/N Carbon to Nitrogen Ratio

DF Dry Fermentation

HS High Solids

MBT Mechanical Biological Treatment

MSW Municipal Solid Waste

OLR Organic Load Rate

O&M Operating and Maintenance

RT Retention Time

SET Sale Energy Tariff

TS Total Solids

VS Volatile Solids

WWDC Waste Water Disposal Costs

1

1. Introduction and purpose of the work

1.1 Motivation of this study

Biodegradable fraction of municipal waste represents 65 – 70% of total quantity of

municipal waste out of which biogas (electrical energy) is produced through the

process of anaerobic biological treatment. Taking into consideration the above-

mentioned and the daily quantity of newly generated municipal waste which is

constantly increasing, two goals may be achieved by using the generated biogas:

waste management and renewable energy. Anaerobic digestion (AD), as one of

today’s most popular anaerobic biological treatment technologies, has shown certain

disadvantages primarily due to the relatively high investment and operational costs,

and a very high cost of waste (percolate) water treatment created in the process itself.

Since the so-called wet process is concerned in which the total solids to water ratio is

20% to 80%, the quantity of these percolate waters are rather high and their treatment

represents a major item in the total waste management price.

A “new” technology called dry fermentation (DF) appeared on the market in the past

few years which uses, as its name says, a significantly less amount of water in the

process. The ratio of total solids to water part in the dry fermentation is 50% to 50%,

and in that way a significantly smaller amounts of waste waters that should be

additionally treated and managed are produced.

In addition to waste waters treatment, the waste manipulation itself during dry

fermentation process is simpler than in AD process. Contrary to AD where the

prepared material for biological treatment is being transported through pumps and

pipes (energy consumption and high maintenance cost) the waste manipulation in dry

fermentation which works via a batch process is carried out by wheel loader.

The second important fact is that experiences show that higher quantity of biogas is

produced out of 1 ton of biodegradable municipal waste fraction through AD process

than DF process.

Above mentioned pro and con facts were the main motives for comparison of two

mentioned anaerobic technologies related to the biological treatment of

biodegradable municipal waste fraction. Specifically the work was an endeavour to

compare biogas investment, treatment and production costs through a detailed

2

economic analysis which had as a goal a presentation of sufficiently reliable data

which may serve for choosing among these two technologies of anaerobic biological

treatment.

1.2 Core question

This work should provide the following replies to the basic questions regarding the

above mentioned technologies:

Which are the most important costs of biodegradable waste treatment that

differ essentially in analysed technologies and in which way they influence the

cost of biogas production

In which way the cost of waste (percolate) water management and treatment

influence the price of biogas production

In which way the price of biogas production changes depending on size of

waste treatment plant

In which way sale energy tariff influences profitability of use of suggested

anaerobic process technologies

In which way Gate Fee is altered depending on size of the plant and change of

chosen variables – cost of waste water treatment and sale energy tariff

1.3 Method of approach

Alongside determined initial assumptions equally valid for both analysed

technologies (Chapter 5.1), and taking into account four assumed incoming

capacities of waste treatment plant, all necessary investments regarding building

works and technological equipment have been worked out identically and in detail.

Furthermore, all operative costs have been worked out to great details as well as the

costs of treatment and management of output fractions after treatment. On the basis

of calculated economic parameters of all costs for both technologies the analysis and

comparison has been carried out and the results are shown graphically.

1.4 The structure of the work

At the beginning of this work, a short depiction of anaerobic biological treatment is

given as some sort of introduction to the topic. The following two chapters describe

3

and analyse both of the chosen anaerobic biological treatment technologies:

Anaerobic Digestion and Dry Fermentation. Chapter 5 provides basic technical and

financial assumptions and describes in detail the manner of calculations within the

financial model. In two chapters which follow afterwards the results of calculations

for both technologies are shown in tables and graphically, while chapter 8 gives

comparison of results for both calculations. In Chapter 9, the results are analysed,

conclusion formulated regarding the comparison of the results and the

recommendations offered for possible future continuation of this work.

1.5 Citation of main literature

The literature cited in this study is mainly about the general technical description of

the Anaerobic Digestion and Dry Fermentation technologies.

All detailed technical information about anaerobic biological technology and relevant

economical input data used for the economical analysis and evaluation regarding

Anaerobic Digestion case had been obtained from the firm Daneco Impianti srl,

Milano Italy and for the Dry Fermentation case from the firm Eggersmann

Anlagenbau GmbH, Bad Oeynhausen, Germany.

4

2. Anaerobic biological treatment of municipal solid waste

2.1 Definition of the Municipal Solid Waste

Municipal Solid Waste (MSW), a by-product of modern society, has grown

dramatically in quantity and complexity in the last 50 years. This is particularly true

in wealthy societies which have become consumers of products and discarders of

waste on an epic scale.

The organic compound fraction of MSW represents up to 70% of the waste

composition and consists of paper, garden waste, food waste and other organic waste

including plastics.

Typical structure of the MSW is presented in Table 2.1 below

Table 2.1 Typical structure of the MSW

Waste component Mass proportion (%)

min average* max

Paper 17,57 25,10 32,63

Metal 4,94 7,06 9,18

Glass 3,61 5,16 6,71

Plastic 11,84 16,92 22,00

Wood 1,67 2,39 3,11

Rubber 0,60 0,85 1,11

Textile 3,20 4,57 5,94

Skin 0,45 0,64 0,83

An organic waste 9,88 14,12 18,36

Other organic waste 16,16 23,08 30,00

Other 0,08 0,12 0,16

Total 100,00

5

2.2 Biochemical Reactions

The process of anaerobic biological treatment uses specialised bacteria to degrade

organic part of the waste by turning it into a stable solid and biogas. Biogas is

principally a mixture of carbon dioxide and methane. Anaerobic biological processes

occur in nature in oxygen-free environment such as bogs, landfills and similar.

Anaerobic biological treatment is in fact a series of chemical reactions during which

the organic matter is being decomposed through metabolic transformation with

presence of microorganisms in the oxygen-free environment. Controlled anaerobic

biological process can be applied to any biodegradable material including food,

paper, sludge, solid waste taking into account various levels of success in

degradation of these materials.

Biodegradable fraction of the municipal solid waste is a complex mixture requesting

a series of metabolic reactions necessary for its degradation.

The complete degradation process of municipal solid waste can be described through

four phases as illustrated in Figure 2.1

Figure 2.1 The Four Phases of Anaerobic Process (Garcia-Heras, 2003)

6

Hydrolysis is a phase in which the large chains of organic compounds are broken

down into simple organic molecules; during acidogenesis simple organic compounds

are transformed into simple organic acids (volatile fatty acids); in acetogenesis phase

volatile fatty acids are transformed to acetate; while methanogenesis produces

methane from acetate or hydrogen.

The three major pathways for methanogenesis are (Brandle Group Inc, 2010):

CO2 + 4H2 → CH4 + 2H2O

4CH3COOH → 4CH4 + 4CO2

4CH3OH + 6H2 → 3CH4 + 2H2O

Another way to describe the four phases of anaerobic process is as illustrated in

Figure 2.2

Figure 2.2 The Four Phases of Anaerobic Process (Brendle Group Inc, 2010)

7

The anaerobic biological treatment itself is not finalised until the complete mixture

has not passed through all the aforementioned phases, each of which contains a

unique bacterial population responsible for different ecological conditions.

Described principle of chemical and biological degradation is the same, for both,

anaerobic digestion (AD) as well as dry fermentation (DF) processes.

The chemical processes which occur in each individual phase of the anaerobic

biological treatment will not be described in this thesis.

2.3 Products of anaerobic biological treatment

Final products of anaerobic digestion and dry fermentation are biogas and digestate,

a wet solid obtained through the process of straining process liquids in order to

separate water and solid material. The main components of biogas depend on the

process of anaerobic treatment, but mostly it consists of methane and carbon oxide.

Digestate is a stabile organic material while its quality depends on the quality of the

input biodegradable material in the anaerobic treatment process.

2.3.1 Biogas

The production of biogas is the most valuable aspect of the anaerobic biological

treatment. Typical values of the quantity of biogas production from one ton of the

input biodegradable fraction of municipal waste range from 80 to 150 m3. Such

quantity depends on the quality of the input waste processed at the plant; specifically

it depends on selected technology of anaerobic treatment.

The production of biogas will vary according to many factors. These parameters are

mainly quantity of biodegradable waste, biodegradability, volatile solid content,

moisture and biogas conversion potential.

The equation used to determine the biogas production (Bichsel, Glaude, Burnham,

2008):

BV = BW * (1 –MC) * VS * BF * BP

8

Where

BV = Volume of biogas

BW = Quantity of biodegradable waste

MC = Moisture content of biodegradable waste (%)

VS = Volatile solid content

BF = Biodegradable Factor

BP = Biogas potential

Biogas is primarily composed of methane (CH4) and carbon dioxide (CO2), and

small quantities of hydrogen sulphide (H2S) and ammonia (NH3). Traces of hydrogen

(H2) may be found in biogas, nitrogen (N2) and carbon monoxide (CO). Saturated or

halogenated carbohydrates and oxygen (O2) are only temporarily present in biogas.

As a rule this mixed gas is saturated by water vapour and may contain dust particles

and siloxanes.

Table 2.2 Typical composition of biogas (Monnet, 2003)

Constituents Units Biogas

Methane CH4 Vol% 55 - 70

Carbon oxide CO2 Vol% 30 - 45

Nitrogen N2 Vol% 0 - 2

Hydrogen H2 Vol% trace to less than 1 %

Hydrogen sulphide H2S ppm ~500

Ammonia NH3 ppm ~100

Carbon monoxide CO ppm trace

The composition of biogas obtained by anaerobic biological treatment differs from

the composition of natural gas, but is very similar to a composition of landfill gas.

The caloric value of natural gas is 36.14 MJ/m3 while the caloric value for biogas is

21.48 MJ/m3 (Monnet, 2003)

Biogas may be used for various applications as well as natural gas, subject to some

further upgrading, for example it can be used for heating using boilers, in Combined

Heat and Power (CHP) units or as a fuel for vehicles.

9

This thesis will focus on biogas as a fuel for CHP units, specifically attention will be

paid to production of electricity and heat from biogas.

2.3.2 Digestate

The digestate coming out from Anaerobic Digestion (AD) process is a thick sludge

having a water content of approximately 80 – 85 %. Taking into account that

transport of such a material is economically unjustifiable, and is also inappropriate

for further aerobic biological treatment, digestate is pressed and strained and in that

way its water content decreases to approximately 40%, while leachate is collected

and partly recycled during the process and partly transferred for further treatment at

the waste water treatment plant. Contrary to the AD, digestate left after dry

fermentation process in which incomparably less process water is used and which is

almost 100% recycled, has a significantly lower water content (around 50 – 65%)

therefore it is not subject to further straining but may be directly taken for further

aerobic biological treatment.

Fresh digestate has a very unpleasant smell thus the entire process of digestate

treatment has to be conducted in the closed building, while special attention has to be

paid to aspiration and air control of the working environment, and the air has to pass

through the biofilter before it is released into the atmosphere.

Only soluble organics are degraded in the process of anaerobic treatment, while other

materials, in case they are present in the input biodegradable waste, for example the

inert materials such as glass or plastics, or for example trace elements and heavy

metal or salts will remain present in digestate even after its biological treatment.

Therefore pre-treatment and separation of input biodegradable waste into the

processes of anaerobic biological treatment are very important.

Taking into consideration hygienic quality of the digestate it is necessary to conduct

continuous measurements of concentration of pathogens present. Pathogen

destruction may be guaranteed by a temperature and solid retention time in the

process itself. Therefore, in case it concerns a process involving thermophilic

temperature range and long retention time, very high level of pathogen destruction

may be guaranteed. Satisfactory pathogen destruction level may also be achieved by

mesophilic temperatures and shorter retention time of material in the process.

10

Generally speaking, if the process temperature is lower and retention period is

shorter the output material from the anaerobic treatment process will be more

biologically active.

The common temperature range of anaerobic biological treatment is from 20 – 65 oC

while the usual retention time is 12 – 30 days.

Digestate obtained through anaerobic biological treatment is most commonly

processed anaerobically and can be further matured into compost. The digestate

quality directly depends on the quality of input biodegradable waste in the anaerobic

biological treatment process.

Formula that can be used for determination of digestate production is (Bichsel,

Glaude, Burnham, 2008):

Biodegradable Waste + Water = Biogas + Digestate

2.4 General advantages of anaerobic biological treatment

There are number of advantages and benefits coming out of using anaerobic

biological treatment described in Table 2.2

Table 2.3 – Benefits from anaerobic biological treatment (Binod, 2008)

Waste treatment benefits Energy benefits

Needs less space than aerobic

biological treatments

Natural waste treatment process

Waste disposal reducing

Produce renewable fuel

Net energy producing

Reducing of CO2 emissions

Economic benefits Environmental

More cost – effective from a life

cycle perspective

Reducing of CO2 and CH4 emissions

Odour reduction

Production of compost and fertilizer

11

3. Anaerobic Digestion technology overview

3.1 Process description

Anaerobic Digestion (AD) process of municipal solid waste (MSW) can be divided

into 4 phases: pre-treatment, digestion, production of energy from biogas and post

treatment of digestate.

The scheme below (Figure 3.1 ) shows the general process of an Anaerobic digestion

plant.

Figure 3.1 The general process for an AD plant

3.1.1 Pre-Treatment

A level of pre-treatment depends on the quality of biodegradable waste brought to

the plant. In case a source separation of biodegradable waste exists, the quality of

input material will be greater and the pre-treatment plant simpler. On the other hand,

in case there does not exist source separation of biodegradable fraction of municipal

solid waste it is necessary to separate biodegradable fraction from the mixed MSW

resulting in more complex mechanical pre-treatment.

12

Pre-treatment process must minimally include:

− Removing the non-biodegradable materials (metals, inert materials plastic…)

− Sieving and reducing the size of the material to uniform particles for efficient

biological treatment

− Removing materials which may cause damage to the plant

− Removing materials which may decrease the quality of digestate

As mentioned already, mechanical pre-treatment of mixed municipal waste leads to a

lower quality digestate, because removal of all contaminants is not entirely possible,

especially for smaller particles such as heavy metals.

Pre-treatment process of mixed municipal waste most commonly consists of:

− Manual sorting

− Shredding

− Screening

− Air separation

− Ferrous separation

− Metal separation

3.1.2 Digestion

Digestion of biodegradable waste is carried out in digesters. There are several

various types of digesters which may be classified according to the following

categories (Monnet, 2003):

single stage

o low solid

o high solid

− multi stage

− batch

o single stage system

o sequential system

Which type of digester will be used depend on the temperature range of the

digestion, mesophilic or thermophilic, as well as the solid content.

Figure 3.2 indicates the classification of AD based on the operating criteria

13

Figure 3.2 Classification of AD by operational criteria (Evans,2001)

The digester should be sized according to the volume to be treated. The equation

used to determine the useful volume of the digester is (Bichsel, Glaude, Burnham,

2008):

DV = BW * WD * DF * DT

Where

DV = Useful digester volume

BW = Quantity of biodegradable waste

WD = Waste density

DF = Dilution factor

RT = Retention time

Dilution factor can be expressed as:

DF = VS Content/(RT * Loading Rate)

14

and

VS Content = (TS Fraction) * (VS/TS Fraction) * WD

In order to reduce the quantity of digestate to transport, water must be removed, thus

increasing the concentration of solids. The amount of water to remove can be

calculated using the following formula:

MR = M * (1 – MI/MF)

Where

MR = Water to remove

M = Quantity of digestate

MI = Moisture content initial (%)

MF = Moisture content final (%)

3.1.3 Post Treatment of digestate form AD

Digestate usually requires additional treatment after AD process before it can be used

for fertilizer or soil amendment. In case the input material is processed wet, digestate

may be spread directly on land and soil as slurry or it can be separated into a solid

and liquid fraction. The solid fraction is left to mature for about two to four weeks in

order to obtain dry and entirely stabilized compost. The liquid fraction is recycled

and used for the dilution of fresh waste. It can be applied directly onto farmland as a

liquid fertilizer, or sent furthermore to a wastewater treatment plant. If the

biodegradable fraction of municipal solid waste is treated in a dry process, the

digested material does not contain water and is matured to compost.

Most of the liquor is recycled to moisten the incoming raw biodegradable fraction,

but a surplus will be left that can be spread on farmland as a liquid fertilizer, or

furthermore treated in a wastewater treatment plant. The amount, quality and nature

of digestate depend upon the quality of the incoming material originally fed to the

anaerobic digestion process, the method of digestion, and the duration of the post-

treatment process. As the digestate can be used as soil conditioner after post

15

treatment, the energy consumption in fertilizer manufacturing could be reduced

(Monnet, 2003). Use of digestate or liquor on soil or farmland depends on digestate

quality and local regulations.

Possible use of anaerobic digestion residues as soil amendments improves the

economics and environmental benefits of the anaerobic digestion process. Utilization

of this residue depends largely on its agricultural characteristics and pollution

potential which can be evaluated on the basis of physical, chemical and biological

characteristics. The chemical characteristics of digestate are related to the presence

of heavy metals and other inorganic contaminants as well as persistence organic

contaminants and nutrients like Nitrogen, Phosphorus and Potash (NPK).

Since organic waste can contain hazardous materials, which can result in new ways

of transmission of pathogens and diseases between animals, humans and

environment, quality control of this type of biomass is essential regarding the

biological treatment.

The presence of contaminants in the digestate may cause a negative public opinion of

the AD technology. It may as well damage environment and increase operational

costs. Digestate may contain physical impurities such as: plastic, rubber, glass, metal,

ceramics, sand, stones and cellulosic materials. The contamination of the digestate

depends on the quality of the original feedstock, the pre-treatment process and

digestion itself. Source segregation is more efficient for the digestion of MSW than

mixed collection since the mechanical pre-treatments are less effective in removing

contaminants than elimination of potential contaminants at source.

Dewatering of digestate

Upon finalization of the anaerobic digestion process the digestate is usually sent for

post treatment. Such treatment includes: dewatering, aeration and leachate treatment.

Commonly, fiber and liquor which digestate contains has to be separated. The

following methods of dewatering exist: centrifuges, decanters, screw press, wire

presses and cyclones. The digestate is filtered to remove most of its water content

and the filter case is cured aerobically to form the compost product. The fiber is

bulky and contains a low level of plant nutrients therefore it is used as soil

conditioner, while the liquor contains a large proportion of nutrients and can be used

as a fertilizer. Its high moisture content makes its application through conventional

irrigation methods easier. However, attention has to be paid to application time in

16

order for the nitrogen to be taken up by the crop and not leached into the soil and

groundwater afterwards.

Composting of digestate (Intensive Maturation)

In order to obtain a high quality product with a very high value, the digestate should

be furthermore processed into compost. A composting process would ensure a

complete breakdown of the organic components as well as fixing the mineral

nitrogen on humus like fraction reducing nitrogen loss. As an additive to composting

process, it provides a good source of nitrogen which speeds up the process and at the

same time enriches the compost in phosphorus and micro nutrients such as

manganese (Mg), iron (Fe) etc. The water content of the digestate is also important

for keeping the moisture throughout the composting process. The compost which is

made from MSW should meet consumer and market requirements. The following

criteria are important in order to ensure the marketability:

- It must be contaminant free to a great extent

- It must not present any health hazards

- The level of toxic substances and heavy metals must comply with the

standards

17

3.2 Conditions and variables influencing AD

In order to achieve a satisfactory level of degradation of biodegradable fraction of

municipal solid waste it is necessary to ensure optimal process conditions and

parameters which would enable microbiological activity and increase efficiency of

anaerobic digestion (AD).

Some of the most important parameters necessary for good quality anaerobic

treatment are the following:

− Total Solid Content

− Temperature

− Retention Time

− pH

− Carbon to Nitrogen Ratio (C/N)

− Mixing

− Organic Loading rate/Volatile Solids

3.2.1 Total Solid Content

There are three different ranges of solid content: low solid (LS) which contains less

than 10% solid content, medium solid (MS) with solid content of 15 – 20% and high

solid (HS) with solid content of 20 – 40%.

An increase in the quantity of solid content automatically decreases the volume of

the digester because of the smaller quantity of necessary process water.

3.2.2 Temperature

We differentiate two temperature ranges of the AD process (Monnet 2003):

-Mesophilic conditions, between 20-45°C, usually 35°C.

-Thermophilic conditions, between 50-65° C, usually 55°C.

Optimal temperature of digestion varies depending on the type of biodegradable

material fed into the AD process and the type of digester, but it is important to

mention that it is necessary to maintain a constant temperature in order to sustain the

maximum gas production rate. Digesters which operate at thermophilic temperatures

are, generally speaking, more efficient due to the shorter retention time and nominal

18

production of biogas, but they need a higher heat input for proper functioning and are

very sensitive to operating and environmental variables, and thus more unreliable in

operating sense in comparison with digesters operating at mesophilic temperatures.

3.2.3 Retention time

Retention time is the time needed to achieve the complete degradation of the organic

matter. The retention time varies for different processes and parameters, such as

process temperature and waste composition.

Retention time necessary for digestion of biodegradable fraction of municipal waste

ranges from 15 to 30 days.

Retention time can be expressed with simple formula as (Monnet, 2003):

RT = DV / FR

Where

RT = Retention time

DV = Digester volume (m3)

FR = Flow rate (m3/d)

3.2.4 pH

The optimal pH values for the acidogenesis and methanogenesis phases are different.

Since acetic, lactic and propionic acids are formed during acidogenesis pH falls. A

low pH value may stop the acidogenesis phase, specifically pH value below 6.4 may

be toxic for methane-forming bacteria.

An optimal pH value for complete anaerobic digestion process is between 6.4 and

7.2.

3.2.5 Carbon to Nitrogen ratio (C/N)

The relationship between the amount of carbon and nitrogen present in biodegradable

material may be seen from the C/N ratio. An optimal C/N ratio is between 20 – 30

(Monnet, 2003).

19

A high C/N ratio indicates a fast consumption of nitrogen by the methanogens

resulting in lower biogas production, while on the other hand a lower C/N ratio

causes ammonia accumulation and higher pH values which is toxic to methanogenic

bacteria.

3.2.6 Mixing

Mixing materials within the digester improves the contact between microorganisms

and substrate, and improves the ability of the bacterial population to obtain nutrients.

Mixing also prevents the formation of scum and temperature increase within the

digester.

3.2.7 Organic Loading Rate/Volatile Solids

Organic Loading Rate is a measure of the biological conversion capacity within the

AD. Loading the AD system above its OLR results in reduced production of biogas

due to accumulation of inappropriate substances in the slurry of the digester. Under

such circumstances, it is necessary to reduce the feeding rate of new material into

digester. Thus OLR is extremely important parameter in continuous AD systems.

OLR is expressed in kg Chemical Oxygen Demand (COD) or in Volatile Solids (VS)

per cubic meter of digester. Volatile solids represent the organic matter in a pattern

which is measured as solid content minus ash content, as obtained by complete

combustion of the feed wastes (IWM, 2001).

20

4. Dry Fermentation technology overview

Dry fermentation is a process of anaerobic biological treatment which enables

methane production form organic matter with a high content of dry matter. It is

mostly based on batch principle, with a dry matter content ranging from 35 to 50 %

at mesophilic temperatures.

4.1 Process description

All Dry Fermentation technologies present on the market are mostly batch processes.

The fermenters are fed up with fresh substrate, closed and let to ferment. At the end

of the cycle the entire residue has to be removed. After removing the residue from

the fermenter, the process is repeated all over again.

Dry fermentation process also passes through the same stages similar to the AD

technology; hydrolysis, acidogenesis, acetogenesis and finally the methanogenesis

stage.

The biological degradation process in dry fermenting occurs upon accumulation of

free fluids. Microorganisms break down solid materials into solution (hydrolysis)

through development of organic acids. Active mixing in the percolation system does

not exist thus the transport of these dissolved materials occurs by the circulating

percolate. Percolate is sprayed on the fermenting pile in the fermenters. The fluid

then flows through the pile collecting the organic acids and transporting and mixing

them with the next stage microorganisms in order for the degradation to continue.

These steps take place is the percolate storage tank and in such a way a considerable

amount of biogas is produced. (Köttner, 2003)

After the input biodegradable feedstock was stored for one to three days and subject

to little pre-treatment, aerobic biological conversion in the material takes place which

is balancing the acidification of the starting anaerobic phase. Fermentation occurs at

mesophilic temperatures of 35 – 40oC, which are regulated through heated floors and

walls. An increase in temperature in aerobic phase catalyses the beginning of the

anaerobic mesophilic phase. Self-heating at the beginning of the phase reduces the

heat requirements in the continuation of the process. Temperature is controlled at 35

– 40˚C by spraying self-fed percolation liquid over the organic matter in the

ferementer and is furthermore regulated through heated floors and walls. In addition

21

a heat exchanger warms the percolation liquid. After 20 - 30 days retention time,

production of biogas is reduced to almost zero and the fermenters are emptied. The

venting period which is introduced in order to hygenize the residues then follows. It

ensures that no anaerobic bacteria remain in the digestate. Emissions of methane,

ammonia and odour should be minimized and the material removed. When digestate

is unloaded, both, the gas space in the dry fermenter is methane-free and new

formation of methane in the fermentation residue is prevented while digestate’s

odour is neutralised. Digestate is unloaded with wheel-loaders and transported for

further aerobic processing.

There is no need for constant mixing, additional pumping and stirring in the digester

during the fermentation process. Dry fermentation technology is therefore much

simpler.

The scheme below (Figure 4.1 ) shows the general process of Dry Fermentation

plant.

Figure 4.1 The General process for an Dry Fermentation plant

22

4.1.1 Pre-Treatment

Contrary to AD, taking into consideration that manipulation of the biodegradable

fraction of waste is conducted by front-end loader and that the material is standing

still during the process, practically no pre-treatment of organic waste is required.

4.1.2 Fermenters

The fermenters are gas-tight, concrete, tunnel-like chambers and can be filled and

emptied with front-end loaders. The material used in the process is dry stacked and is

loaded directly into the tunnel. When the material is loaded and the fermenter is full,

the gates are closed and the fermentation process is carried out. When the process is

completed, the digested material is mechanically emptied. Once the gates are opened

the emissions of the residual biogas to the atmosphere begins (Köttner, 2002).

The atmosphere in and around the system goes through the explosive range twice

each cycle. At that particular point the mixture of methane and oxygen sustain

combustion. It is the critical point at which a spark might ignite the gas cloud in and

around the tunnel. This occurs when the gates are opened and the digestate is

removed and then again after the gates are closed and the first methane is produced

which mixes with the oxygen rich air which enters at the time the material is fed into

the fermenter.

Thus, a real risk of explosion exists in the fermenter when the fermentation is

complete and the gates are opened. This risk continues all the way until the methane

dissolves into the environment. The operator must ensure safety of its plants and

guarantee that the highest safety standards are met.

4.1.3 Process monitoring and control

The most important part of the percolate system lays in its design and management

of dry anaerobic digestion of substrates (Köttner 2002). The volume and frequency

of circulation, as well as the equipment must be sized and sequenced. Understanding

each input material and how it will decompose through the digestion process

becomes the great challenge. Thus process control technology becomes very

important because of various parameters and factors. It should be emphasised that

23

process data can be obtained exclusively by conducting a series of expensive water

tests to determine the right relationship between organic load and buffer capacity

When it finds necessary, according to the calculations of the monitoring device, the

same system will automatically add lime in order to stabilise pH or other substances

to optimise the process.

4.1.4 Heat and Power Generation

The biogas obtained in the dry fermentation process is then dried and gas quality and

volume are measured. The biogas is then pumped through a gas regulating device

with safety installations into a combined heat and power unit. Specially designed

biogas engine generates electricity and heat. Some of the extra heat is used to heat

the digesters, but majority of the heat is available for other use.

24

5. Basic key assumptions for financial analysis

In this work economic aspects and parameters of continuous wet mesophilic

anaerobic digestion and batch mesophilic dry fermentation for four different sizes of

plant, namely 50.000 t/a, 100.000 t/a, 150.000 t/a and finally 200.000 t/a were

analysed and compared. In the further text the basic preconditions observed during

creation of the economic model and calculations were offered, and the manner in

which individual costs were calculated was explained.

5.1 Technical and Financial assumptions

During creation of economic models and calculations, the following technical and

financial preconditions were taken into account:

- It is presumed that 50 % of input MSW is biodegradable fraction suitable for

anaerobic treatment in both processes AD and DF

- Due to simplified calculation of building works investment cost it is

presumed AD and DF digesters with single following dimesions: for AD

digestors with Ø 15 m and height of 15 m and for DF tunnels with

dimensions 27 x 5,5 x 4,1 m (L x W x H)

- In AD as well as in DF case the presumed duration of the process of

anaerobic biological treatment is 21 days

- It is presumed that post maturation investment and operational costs are the

same for both processes and as such they have not been taken into

consideration during calculations

- The costs of building the infrastructure and necessary roads within the plant

were not taken into consideration because it was presumed that they were the

same for both processes

- During calculation the revenues form thermal energy production from biogas

motors were not taken into account. Each of these processes uses the

generated thermal energy only for the purpose of warming up their own

digesters.

- During calculation the Electrical Conversion Efficiency coefficient ηel in

value of 38 % are taken into account as a fix value for the both processes

25

- During calculation the revenues from greenhouse-gas production savings

were not taken into account

- In the waste water disposal costs, transport costs from the plant to the waste

water disposal facility were not taken into account

- During calculation of investment costs estimating allowance of 10% was

considered

- During calculation of operating and maintenance costs, unforeseen costs of

10% and estimating allowance of 10% were taken into account

- All Gate Fee costs are calculated in relation to input plant capacity and results

are expressed in €/t

5.2 Total costs calculation

Total plant costs can be expressed with simple formula as:

CT= CTI + CFC + CO&M + CD + CCE

Where

CT = Total plant costs

CTI = Total Investment costs

CFC = Amortisation and Financial costs

CO&M = Operating & Maintenance costs

CD = Disposal costs

CCE = Corporate earnings

5.3 Calculation of Investment costs

The total Investment costs are calculated as follows:

CTI = CLA + CBW + CEMW

Where

CTI = Total Investment costs

CLA = Land acquisition costs

CBW = Building Works costs

CEMW = Electro-Mechanical Works costs

26

5.3.1 Building Works costs and Electro – Mechanical Works costs for AD

Building Works costs CBW for AD are calculated using the following formula:

CBW = CBMP + CBBP + CBBT + CBDW + CBIM + CBCHP

Where

CBMP = Building Works costs for mechanical pre-treatment including Solid

Recovered Fuel (SRF) production

CBBP = Building Works costs for biological pre-treatment

CBBT = Building Works costs for biological treatment

CBDW = Building Works costs for dewatering

CBIM = Building Works costs for intensive maturation

CBCHP = Building Works costs for biogas cogeneration plant including gas

cleaning

Electro-Mechanical Works costs CEMW for AD are calculated using the following

formula:

CEMW = CEMP + CEBP + CEBT + CEDW + CEIM + CECHP

Where

CEMP = Electro-Mechanical Works costs for mechanical pre-treatment

including Solid Recovered Fuel (SRF) production

CEBP = Electro-Mechanical Works costs for biological pre-treatment

CEBT = Electro-Mechanical Works costs for biological treatment

CEDW = Electro-Mechanical Works costs for dewatering

CEIM = Electro-Mechanical Works costs for intensive maturation

CECHP = Electro-Mechanical Works costs for biogas cogeneration plant

including gas cleaning

27

5.3.2 Building Works costs and Electro – Mechanical Works costs for DF

Thanks to no need of biological pre-treatment before DF and dewatering before

intensive maturation Building Works costs CBW for DF are calculated using the

simplified formula:

CBW = CMP + CBT + CIM + CCHP

Where

CMP = Building Works costs for mechanical pre-treatment including Solid

Recovered Fuel (SRF) production

CBT = Building Works costs for biological pre-treatment

CIM = Building Works costs for intensive maturation

CCHP = Building Works costs for biogas cogeneration plant including gas

cleaning

Electro-Mechanical Works costs CEMW for DF are calculated using the following

formula:

CEMW = CEMP + CEBT + CEIM + CECHP

Where

CEMP = Electro-Mechanical Works costs for mechanical pre-treatment

including Solid Recovered Fuel (SRF) production

CEBT = Electro-Mechanical Works costs for biological pre-treatment

CEIM = Electro-Mechanical Works costs for intensive maturation

CECHP = Electro-Mechanical Works costs for biogas cogeneration plant

including gas cleaning

28

5.4 Calculation of Amortisation and Financing costs

Amortisation and financial costs are calculated according to the following formula:

Where

A = Payment amount per period

P = Plant value

r = Interest rate per period

n = Total number of payments or periods

In our case we presume:

r = 6 %

n = 30 semi-annual amortization instalments

5.5 Calculation of Operating and Maintenance costs

The total Operating and Maintenance (O&M) costs are calculated as follows:

CO&M = CEE + CPC + CMC + CMMC +CAN

Where

CO&M = Total O & M costs

CEE = Electrical Energy costs

CPC = Personnel costs

CMC = Maintenance costs

CMMC = Mobile Vehicle Maintenance costs

CAN = Analysis costs

5.6 Disposal costs

The following disposal costs are taken into account in the total costs calculation.

Disposal costs for solids (landfill costs)

Disposal costs for SRF

29

Disposal costs for waste water (percolate)

5.7 Corporate earnings

Corporate earnings or company's profits is calculated with 18% on the sum of O&M

costs and disposal costs.

5.8 Revenues

Calculated expected revenues come from two resources, electricity production from

biogas and from separated metal sale.

Biogas production from 1 ton of input biodegradable waste in anaerobic process is

calculated with 120 m3 for Anaerobic Digestion and with 80 m

3 for Dry

Fermentation.

Presumed electrical conversion efficiency for biogas motor is 38% and thermal

conversion efficiency is calculated with 45%.

Revenues from metal sale are calculated with fix selling price for both processes.

5.9 Gate Fee calculation

A gate fee (or tipping fee) is the charge levied upon a given quantity of waste

received at a waste processing facility and can be calculated as Total plant costs

minus Revenues or by using following formula:

GF= CT - R

Where

GF = Gate Fee

CT = Total plant costs

R = Revenues from anaerobic treatment plant

According to our comparison and analysis of AD and DF, the level of Gate Fee will

in the end show profitability of the plant installation for anaerobic treatment.

http://en.wikipedia.org/wiki/Waste

30

6. Technical and Economic Aspects of Anaerobic

Digestion

The Anaerobic Digestion process and technology analysed in this work comprises:

receipt and inspection area for input waste, mechanical pre-treatment, biological pre-

treatment, anaerobic biological treatment, dewatering plant, intensive maturation

plant, post maturation and combined heat and power (CHP) plant.

An economic analysis is carried out for four plant sizes of AD facilities: 50.000 t/a,

100.000 t/a, 150.000 t/a and 200.000 t/a of input Municipal Solid Waste. Results are

presented in Table 6.1.

Table 6.1 Economic analysis of AD at different scales

MSW 50.000 100.000 150.000 200.000

Unit t/a t/a t/a t/a

Land acquistion costs € * 106 1,17 1,97 3,01 4,17

Building Works costs € * 106 3,30 5,51 8,34 11,48

Electro-Mechanical Works costs € * 106 9,74 15,22 21,04 25,81

TOTAL INVESTMENT COSTS € * 106 14,21 22,70 32,39 41,46

UNIT INVESTMENT COSTS €/t/a 284,21 227,04 215,92 207,28

TOTAL O&M COSTS € * 106/a 1,45 2,32 3,30 4,23

BIOGAS PRODUCTION m3/a 3.000.000 6.000.000 9.000.000 12.000.000

EL. ENRGY PRODUCTION kWh/a 6.646.200 13.292.400 19.938.600 26.584.800

SPEC. INVESTMENT COSTS €/m3

biogas 5,55 4,15 3,76 3,49

SPEC. INVESTMENT COSTS €/kWh 2,50 1,87 1,70 1,57

ANAEROBIC DIGESTION MBT PLANT

Capacity

The electricity is produced at 38% efficiency and thermal energy is produced at 45%

efficiency. This may be noted as bellow taking into account biogas calorific value of

21 MJ/Nm3 and 120 m

3 biogas per

ton of input waste:

[(120 m3/t * 21MJ/Nm

3 * 1000 kJ/MJ) / 3600 kJ/kWh] * 38/100 = 266 kWeh/t

[(120 m3/t * 21MJ/Nm

3 * 1000 kJ/MJ) / 3600 kJ/kWh] * 45/100 = 315 kWth/t

Figure 6.1 highlights the AD Total Investment Costs for different plant sizes and

Figure 6.2 highlights AD Unit Investment Costs

31

15,00

20,00

25,00

30,00

35,00

40,00

45,00

50.000 100.000 150.000 200.000

Tota

l in

ves

tmen

t co

sts

€*

10

6

Plant capacity t/a

TOTAL INVESTMENT COSTS AD

Figure 6.1 Total investment costs AD

200,00

220,00

240,00

260,00

280,00

300,00

320,00

340,00

50.000 100.000 150.000 200.000

To

tal

inv

estm

ent

cost

s €

/t/a

Plant capacity t/a

UNIT INVESTMENT COSTS AD

Figure 6.2 Unit investment costs AD

Taking into account biogas and electrical energy production, also specific unit

investment costs of biogas and electricity production can be calculated. The results

are presented in Figures 6.3 and 6.4

32

3,00

3,50

4,00

4,50

5,00

5,50

6,00

50.000 100.000 150.000 200.000

Sp

ec. In

vest

men

t co

st €

/m3

bio

ga

s

Plant capacity t/a

SPEC. INVESTMENT COSTS OF BIOGAS PRODUCTION - AD

Figure 6.3 Specific unit investment costs for biogas production AD

1,00

1,50

2,00

2,50

3,00

3,50

50.000 100.000 150.000 200.000

Sp

ec. In

vest

men

t co

st €

/kW

h

Plant capacity t/a

SPEC. INVESTMENT COSTS OF EL. ENERGY PRODUCTION - AD

Figure 6.4 Specific unit investment costs for electricity production AD

Figure 6.5 explains Mass Balance flow diagram of the process of anaerobic digestion

and shows all quantities of output fraction as waste water, digestate and biogas.

33

Figure 6.5 Mass balance flow diagram of Anaerobic Digestion

34

Figure 6.5 shows the big quantities of the waste water in the AD process relating to

the input MSW quantities; therefore the cost of the waste water disposal is very

important in calculation of total disposal costs. For our calculation we took three

typical waste water disposal tariffs. Impact of waste water disposal price is shown in

the Table 6.2 and graphed as in Figure 6.6

Table 6.2 Total Disposal Costs in correlation with waste water disposal costs AD

MSW 50.000 100.000 150.000 200.000 W.W.D.C

Unit t/a t/a t/a t/a €/m3

TOTAL DISPOSAL COSTS €/a 1.980.000 3.960.000 5.940.000 7.920.000 15




Capacity

2.000.000

3.000.000

4.000.000

5.000.000

6.000.000

7.000.000

8.000.000

9.000.000

10.000.000

50.000 100.000 150.000 200.000

Dis

po

salc

ost

s €

/a

Plant capacity t/a

TOTAL DISPOSAL COSTS PER YEAR

Waste water disposal costs 15 €/m3



Figure 6.6 Total Disposal Costs of AD in correlation with waste water disposal costs

In the similar way the waste water disposal costs influence on the total costs of the

AD plant what can be seen in Table 6.3 and in Figure 6.7

35

Table 6.3 Total Costs in correlation with waste water disposal costs AD

MSW 50.000 100.000 150.000 200.000 W.W.D.C


TOTAL COSTS €/a 6.742.590 10.649.071 14.923.878 18.851.587 15

TOTAL COSTS €/a 6.978.590 11.121.071 15.631.878 19.795.587 25

TOTAL COSTS €/a 7.214.590 11.593.071 16.339.878 20.739.587 35


Capacity

6.500.000

8.500.000

10.500.000

12.500.000

14.500.000

16.500.000

18.500.000

20.500.000

50.000 100.000 150.000 200.000

To

tal c

ost

s €

/a

Plant capacity t/a

TOTAL COSTS PER YEAR




Figure 6.7 Total Costs of AD in correlation with waste water disposal costs

As the total costs are directly related to the waste water disposal costs similarly the

revenues are directly related to the Sale Energy Tariff (S.E.T). For better county

Tariffs comparison we took the Sale Energy Tariff from Italy (0,28 €/kWh), Slovenia

(0,14 €/kWh) and Germany (0,09 €/kWh). The results of calculation are presented in

Table 6.4 and in Figure 6.8.

36

Table 6.4 Total Revenues in correlation with Sale Energy Tariffs AD

MSW 50.000 100.000 150.000 200.000 S.E.T.

Unit t/a t/a t/a t/a €/kWh

TOTAL REVENUES PER YEAR €/a 748.158 1.496.316 2.244.474 2.992.632 0,090

TOTAL REVENUES PER YEAR €/a 1.080.468 2.160.936 3.241.404 4.321.872 0,140



Capacity

500.000

1.500.000

2.500.000

3.500.000

4.500.000

5.500.000

6.500.000

7.500.000

50.000 100.000 150.000 200.000

To

tal r

even

ues

€/a

Plant capacity t/a

TOTAL REVENUES PER YEAR

Sales Energy Tariff 0,09 €/kWh



Figure 6.8 Total Revenues in correlation with Sale Energy Tariffs

37

7. Technical and Economic Aspects of Dry Fermentation

Since Dry Fermentation uses simpler process technology than AD, the facility parts

analysed in this work comprise of: receipt and inspection area for input waste,

mechanical pre-treatment, anaerobic biological treatment, intensive maturation plant,

post maturation and combined heat and power (CHP) plant.

The same economic analysis is carried out for four plant sizes of DF facilities:

50.000 t/a, 100.000 t/a, 150.000 t/a and 200.000 t/a of input Municipal Solid Waste.

Results are presented in Table 7.1.

Table 7.1 Economic analysis of DF at different scales

MSW 50.000 100.000 150.000 200.000

Unit t/a t/a t/a t/a

Land acquistion costs € * 106 1,17 1,97 3,01 4,17

Building Works costs € * 106 3,30 5,51 8,34 11,48

Electro-Mechanical Works costs € * 106 9,74 15,22 21,04 25,81

TOTAL INVESTMENT COSTS € * 106 14,21 22,70 32,39 41,46

UNIT INVESTMENT COSTS €/t/a 284,21 227,04 215,92 207,28

TOTAL O&M COSTS € * 106/a 1,45 2,32 3,30 4,23

BIOGAS PRODUCTION m3/a 2.000.000 4.000.000 6.000.000 8.000.000

EL. ENRGY PRODUCTION kWh/a 4.430.800 8.861.600 13.292.400 17.723.200

SPEC. INVESTMENT COSTS €/m3

biogas 7,11 5,68 5,40 5,18

SPEC. INVESTMENT COSTS €/kWh 3,21 2,56 2,44 2,34

DRY FERMENTATION MBT PLANT

Capacity

The electricity is produced at 38% efficiency and thermal energy is produced at 45%

efficiency. This may be noted as bellow taking into account biogas calorific value of

21 MJ/Nm3 and 80 m

3 biogas per

ton of input waste:

[(80 m3/t * 21MJ/Nm

3 * 1000 kJ/MJ) / 3600 kJ/kWh] * 38/100 = 177,33 kWeh/t

[(80 m3/t * 21MJ/Nm

3 * 1000 kJ/MJ) / 3600 kJ/kWh] * 45/100 = 210 kWth/t

Figure 7.1 displays the DF Total Investment Costs for different plant sizes and

Figure 7.2 shows DF Unit Investment Costs

38

10,00

15,00

20,00

25,00

30,00

35,00

40,00

45,00

50.000 100.000 150.000 200.000

To

tal in

ves

tmen

t co

sts

€*

10

6

Plant capacity t/a

TOTAL INVESTMENT COSTS

DRY FERMENTATION

Figure 7.1 Total investment costs DF

200,00

210,00

220,00

230,00

240,00

250,00

260,00

270,00

280,00

290,00

50.000 100.000 150.000 200.000

Tota

l in

ves

tmen

t co

sts

€/t

/a

Plant capacity t/a

UNIT INVESTMENT COSTS

DRY FERMENTATION

Figure 7.2 Unit investment costs DF

39

The specific unit investment costs of biogas production and electricity production are

calculated in the same way as for AD and results are shown in the Figures 7.3 and

7.4.

4,50

5,00

5,50

6,00

6,50

7,00

7,50

50.000 100.000 150.000 200.000

Sp

ec. In

vest

men

t co

st €

/m3

bio

ga

s

Plant capacity t/a

SPEC. INVESTMENT COSTS OF BIOGAS PRODUCTION - DF

Figure 7.3 Specific unit investment costs for biogas production

2,00

2,20

2,40

2,60

2,80

3,00

3,20

3,40

50.000 100.000 150.000 200.000

Sp

ec. In

vest

men

t co

st €

/kW

h

Plant capacity t/a

SPEC. INVESTMENT COSTS OF EL. ENERGY PRODUCTION - DF

Figure 7.4 Specific unit investment costs for electricity production

40

Figure 7.5 explains Mass Balance flow diagram of the process of dry fermentation

and shows all quantities of output fraction as waste water, digestate and biogas.

Figure 7.5 Mass balance flow diagram of Dry Fermentation

Unlike AD the process of Dry Fermentation does not produce so much waste water

and therefore the variation of waste water disposal costs are not so influential in the

total disposal costs and total costs what can be seen in Tables 7.2 and 7.3 and in

Figure 7.6 and 7.7

Table 7.2 Total Disposal Costs in correlation with waste water disposal costs DF

MSW 50.000 100.000 150.000 200.000 W.W.D.C






Capacity

41

1.700.000

2.700.000

3.700.000

4.700.000

5.700.000

6.700.000

50.000 100.000 150.000 200.000

Dis

po

salc

ost

s €

/a

Plant capacity t/a

TOTAL DISPOSAL COSTS PER YEAR




Figure 7.6 Total Disposal Costs of DF in correlation with waste water disposal costs

Table 7.3 Total Costs in correlation with waste water disposal costs DF

MSW 50.000 100.000 150.000 200.000 W.W.D.C


TOTAL COSTS €/a 6.140.337 9.819.761 13.943.793 17.725.110 15

TOTAL COSTS €/a 6.175.737 9.890.561 14.049.993 17.866.710 25

TOTAL COSTS €/a 6.211.137 9.961.361 14.156.193 18.008.310 35


Capacity

6.000.000

8.000.000

10.000.000

12.000.000

14.000.000

16.000.000

18.000.000

50.000 100.000 150.000 200.000

To

tal c

ost

s €

/a

Plant capacity t/a

TOTAL COSTS PER YEAR




Figure 7.7 Total Costs of DF in correlation with waste water disposal costs

42

The Revenues calculation for Dry Fermentation in correlation with Sale Energy tariff

is presented in Table 7.4 and in Figure 7.8

MSW 50.000 100.000 150.000 200.000 S.E.T.

Unit t/a t/a t/a t/a €/kWh





Capacity

Table 7.4 Total Revenues in correlation with Sale Energy Tariffs DF

500.000

1.500.000

2.500.000

3.500.000

4.500.000

5.500.000

50.000 100.000 150.000 200.000

To

tal r

even

ues

€/a

Plant capacity t/a

TOTAL REVENUES PER YEAR




Figure 7.8 Total Revenues in correlation with Sale Energy Tariffs DF

43

8. Economic Comparison of Anaerobic Digestion and Dry

Fermentation

An economic comparison of Anaerobic Digestion and Dry fermentation is based on

the results shown in chapters 6 and 7 of this work.

After a detailed analysis of economics of both technologies during the preparation of

the economical model for the cost and benefit calculation, two basic variables were

shown as most important economic indicators: the cost of the waste water disposal

and sale energy tariff fee.

An economic comparison is divided in two important parts: comparison of

investment costs and operating and maintenance costs which is not under the

influence from selected variables and comparison of all others economical

parameters important trough the gate fee.

As already explained before, a gate fee (or tipping fee) is the charge levied upon a

given quantity of waste received at a waste processing facility but, in the case of this

economic comparison, represents the value that include changes of both selected

variables together with all other important economic parameters.

In other words, gate fee give us important information about necessary waste

management fee to keep the waste treatment feasible.

Waste management market all over Europe already defined waste management fee

for various treatment of MSW. This fee is changing mostly because of constant

changes of the output fractions disposal costs.

The lower gate fee for the same input capacity shows us opportunity to have bigger

profit and possibility to award waste management contract much easier.

Consequently, anaerobic treatment technology with lower gate fee is more suitable

for specific situation.

http://en.wikipedia.org/wiki/Waste

44

8.1 Economic comparison of the Investment and O&M Costs

The Figures 8.1 and 8.2 show the comparison of investment cost and Figure 8.3

shows comparison of O&M costs between Anaerobic Digestion and Dry

Fermentation.

12,00

17,00

22,00

27,00

32,00

37,00

42,00

50.000 100.000 150.000 200.000

Tota

l in

ves

tmen

t co

sts

€*

10

6

Plant capacity t/a

TOTAL INVESTMENT COSTS

ANAEROBIC

DIGESTION

DRY FERMENTATION

Figure 8.1 – Comparison of Total Investment Costs

200,00

220,00

240,00

260,00

280,00

300,00

320,00

340,00

50.000 100.000 150.000 200.000

Tota

l in

ves

tmen

t co

sts

€/t

/a

Plant capacity t/a

UNIT INVESTMENT COSTS

ANAEROBIC

DIGESTION

DRY FERMENTATION

Figure 8.2 – Comparison of Unit Investment Costs

45

2,00

2,50

3,00

3,50

4,00

4,50

5,00

50.000 100.000 150.000 200.000

Tota

l in

ves

tmen

t co

sts

€*

10

6

Plant capacity t/a

OPERATING & MAINTENANCE COSTS

ANAEROBIC

DIGESTION

DRY FERMENTATION

Figure 8.3 – Comparison of O&M Costs

As can be noticed from the Figures 8.1 and 8.2, the investment costs in the case of

Anaerobic Digestion were higher than the costs of Dry Fermentation for the facilities

with smaller capacity, but the investment costs become more equal as we approach

the facilities with bigger capacity. That can be explained with major necessary

investments in the land acquisition and building works for the Dry Fermentation due

to technological needs.

The O&M comparison shows that O&M costs for the Dry fermentation for the

smaller plants are lower due to simpler technology and less wear and spare parts

needed, but for the facilities with capacity exceeding approximately 100.000 t/a,

Anaerobic Digestion shows lower O&M costs due to the higher automation of the

process and less personal and mobile equipment costs.

Figures 8.4 and 8.5 present a comparison of the specific unit investment cost for

biogas production and electricity production. From the figures we can conclude that

the unit investment for production of biogas and electric energy is smaller for

Anaerobic Digestion than for Dry Fermentation which is pretty logical taking into

account the fact that Anaerobic Digestion process produces more that 30% more

biogas from 1 ton of biodegradable waste when compared with Dry Fermentation.

46

3,00

3,50

4,00

4,50

5,00

5,50

6,00

6,50

7,00

7,50

50.000 100.000 150.000 200.000

Sp

ec. In

vest

men

t co

st €

/m3

bio

ga

s

Plant capacity t/a

SPEC. INVESTMENT COSTS OF BIOGAS PRODUCTION

ANAEROBIC DIGESTION

DRY FERMENTATION

Figure 8.4 Comparison of Specific Investment Costs for biogas production

1,00

1,50

2,00

2,50

3,00

3,50

50.000 100.000 150.000 200.000

Sp

ec. In

vest

men

t co

st €

/kW

h

Plant capacity t/a

SPEC. INVESTMENT COSTS OF EL. ENERGY PRODUCTION

ANAEROBIC DIGESTION

DRY FERMENTATION

Figure 8.5 Comparison of Specific Investment Costs for electrical energy production

47

8.2 Economic comparison of the Gate Fee

The comparison of Gate Fee is made for all combinations between selected variables

in order to get a complete scale of information necessary to decide in which cases

Anaerobic Digestion is more advanced than Dry Fermentation and vice versa.

The Table 8.1 and Figure 8.6 present Gate Fee comparison for fix Sale Energy Tariff

of 0,09 €/kWh and waste water disposal cost changing from 15 to 35 €/m3.


Waste Water disposal cost 15 €/t

Sale Energy Tariff 0,09 €/kWh

MSW 50.000 100.000 150.000 200.000 50.000 100.000 150.000 200.000

Unit t/a t/a t/a t/a t/a t/a t/a t/a

GATE FEE €/t 119,89 91,53 84,53 79,29 111,83 87,22 81,98 77,65



MSW 50.000 100.000 150.000 200.000 50.000 100.000 150.000 200.000


GATE FEE €/t 124,61 96,25 89,25 84,01 112,54 87,93 82,69 78,36



MSW 50.000 100.000 150.000 200.000 50.000 100.000 150.000 200.000


GATE FEE €/t 129,33 100,97 93,97 88,73 113,25 88,64 83,40 79,07

Capacity

Capacity


Capacity

ANAEROBIC DIGESTION MBT PLANT DRY FERMENTATION MBT PLANT

Capacity


Capacity


Capacity

75,00

80,00

85,00

90,00

95,00

100,00

105,00

110,00

115,00

120,00

125,00

50.000 100.000 150.000 200.000

Ga

te F

ee €

/t

Plant capacity t/a

GATE FEE - Sales Energy Tariff 0,09 €/kWh; Waste water diposal cost

15 €/m3

ANAEROBIC

DIGESTION

DRY FERMENTATION

48

75,00

85,00

95,00

105,00

115,00

125,00

135,00

50.000 100.000 150.000 200.000

Gate

Fee

€/t

Plant capacity t/a

GATE FEE - Sales Energy Tariff 0,09 €/kWh; Waste water disposal cost

25 €/m3

ANAEROBIC

DIGESTION

DRY FERMENTATION

75,00

85,00

95,00

105,00

115,00

125,00

135,00

50.000 100.000 150.000 200.000

Gate

Fee

€/t

Plant capacity t/a


35 €/m3

ANAEROBIC

DIGESTION

DRY FERMENTATION


The Table 8.1 and Figure 8.6 indicate that Dry Fermentation is more advanced

technology in all three cases. Low Sale Energy Tariff evidently cannot cover disposal

costs, however a convergence of gate fee can be noted in the case of the waste water

disposal cost of 15 €/m3

.

49

The Table 8.2 and Figure 8.7 present Gate Fee comparison for fix Sale Energy Tariff

of 0,14 €/kWh and waste water disposal cost changing from 15 to 35 €/m3.




MSW 50.000 100.000 150.000 200.000 50.000 100.000 150.000 200.000


GATE FEE €/t 113,24 84,88 77,88 72,65 107,40 82,79 77,55 73,22



MSW 50.000 100.000 150.000 200.000 50.000 100.000 150.000 200.000


GATE FEE €/t 117,96 89,60 82,60 77,37 108,11 83,50 78,26 73,93



MSW 50.000 100.000 150.000 200.000 50.000 100.000 150.000 200.000


GATE FEE €/t 122,68 94,32 87,32 82,09 108,82 84,21 78,97 74,64

Capacity


Capacity Capacity


Capacity Capacity

DRY FERMENTATION MBT PLANTANAEROBIC DIGESTION MBT PLANT


Capacity

70,00

75,00

80,00

85,00

90,00

95,00

100,00

105,00

110,00

115,00

50.000 100.000 150.000 200.000

Gate

Fee

€/t

Plant capacity t/a


15 €/m3

ANAEROBIC

DIGESTION

DRY FERMENTATION

50

70,00

75,00

80,00

85,00

90,00

95,00

100,00

105,00

110,00

115,00

120,00

50.000 100.000 150.000 200.000

Gate

Fee

€/t

Plant capacity t/a


25 €/m3

ANAEROBIC

DIGESTION

DRY FERMENTATION

70,00

80,00

90,00

100,00

110,00

120,00

130,00

50.000 100.000 150.000 200.000

Gate

Fee

€/t

Plant capacity t/a


35 €/m3

ANAEROBIC

DIGESTION

DRY FERMENTATION


In the case of Sale Energy Tariff of 0,14 €/kWh and Waste water disposal cost of 15

€/m3 we can notice that the Dry Fermentation gate fee for the capacity of 200.000 t/a

exceed the gate fee for Anaerobic Digestion and in that case influence of revenue

from electrical energy overcome influence of costs for waste water disposal which

makes Anaerobic Digestion more acceptable as solution.

51

The last Table 8.3 and Figure 8.8 depict Gate Fee comparison for fix Sale Energy

Tariff of 0,28 €/kWh and waste water disposal cost in the same range as in previous

two cases.




MSW 50.000 100.000 150.000 200.000 50.000 100.000 150.000 200.000


GATE FEE €/t 94,63 66,27 59,27 54,04 94,99 70,39 65,15 60,81



MSW 50.000 100.000 150.000 200.000 50.000 100.000 150.000 200.000


GATE FEE €/t 99,35 70,99 63,99 58,76 95,70 71,09 65,85 61,52



MSW 50.000 100.000 150.000 200.000 50.000 100.000 150.000 200.000


GATE FEE €/t 104,07 75,71 68,71 63,48 96,41 71,80 66,56 62,23

Capacity Capacity

Capacity


Capacity Capacity



Capacity

50,00

55,00

60,00

65,00

70,00

75,00

80,00

85,00

90,00

95,00

50.000 100.000 150.000 200.000

Gate

Fee

€/t

Plant capacity t/a


15 €/m3

ANAEROBIC

DIGESTION

DRY FERMENTATION

52

55,00

60,00

65,00

70,00

75,00

80,00

85,00

90,00

95,00

100,00

50.000 100.000 150.000 200.000

Gate

Fee

€/t

Plant capacity t/a


25 €/m3

ANAEROBIC

DIGESTION

DRY FERMENTATION

60,00

65,00

70,00

75,00

80,00

85,00

90,00

95,00

100,00

105,00

50.000 100.000 150.000 200.000

Gate

Fee

€/t

Plant capacity t/a


35 €/m3

ANAEROBIC

DIGESTION

DRY FERMENTATION


The high Sale Energy Tariff brings advance to Anaerobic Digestion in the case of

low and medium waste water disposal costs, however Dry Fermentation is still more

advanced technology for high waste water disposal cost.

53

9. Conclusions and recommendations

9.1 Conclusions

From this analysis and investigation it is concluded that both technologies,

Anaerobic Digestion and Dry Fermentation can be successfully used for the biogas

production from biodegradable fraction of municipal solid waste.

To date experiences regarding the Anaerobic Digestion treatment point at the big

problem related to the waste water treatment cost arising from the biological

treatment process itself. That along with some other technological differences was

the main reason for development of dry fermentation technology.

Anaerobic Digestion demands more investment in pre-treatment of input material

prior to the biological treatment itself alongside with the investment into digestate

post-treatment after anaerobic biological treatment which is not the case in dry

fermentation.

Manipulation of biodegradable waste in case of anaerobic digestion is fully

automatic and is conducted by conveyors, specifically by pumps and pipes, while in

the case of dry fermentation conveyors and mobile vehicles are used. Automatic

manipulation of the material on one hand increases investment cost while on the

other hand it decreases operating costs from the aspect of work force. That is why it

is necessary to conduct a detailed analysis of waste material, its composition and

quality and naturally quantities necessary for treatment.

During economic analysis and development of economic model for calculation of all

relevant costs and incomes for both technologies besides several minor there were

also two very important variables which have a direct impact on profitability of both

technologies. That is waste water disposal cost and amount of sale energy tariff for

the electrical energy produced from biogas.

The result of this research and analysis shows that anaerobic digestion can be

compared economically with dry fermentation only in cases where waste water

disposal costs are low, and sale energy tariff is high, which is not the case

everywhere in Europe.

It is important to mention that waste water disposal costs did not include cost of the

transport of waste (percolate) waters to waste water treatment plant, which

54

additionally emphasises importance of choosing the right site for construction of the

plant.

It is possible to keep the cost of the waste water treatment under control by building

one’s own waste water treatment plant within the plant itself which on the other hand

increases the investment cost of the plant itself.

Sale Energy Tariff (Feed-Inn Tariff) specifically incomes from selling electrical

energy essentially differ in various European states so that it cannot be generally

spoken about higher profitability of one or the other technology of anaerobic

processes, however the local situation regarding the existing costs of treatment of the

output fractions, and incomes from selling produced energy, should be always

analysed in detail.

General conclusion related to the outcome of the conducted analysis and

investigation would be that dry fermentation is recommended for anaerobic treatment

plants of biodegradable fraction of municipal solid waste of smaller and medium

capacities to 100.000 t/a while anaerobic digestion technology is recommended for

larger anaerobic treatment plants above 150.000 t/a.

9.2 Recommendations

Since this work analyses municipal solid waste as input material perhaps some future

work should deal in greater detail and pay special attention to other output fractions

from similar plants for mechanical biological treatment (MBT) especially of solid

recovery fuel fraction as renewable energy source and in that way analyse additional

value produced by using SRF.

As the continuation of this work, the analysis of different scenarios of Greenhouse-

Gas used for both types of technologies would also be recommended.

55

Acknowledgements

I extend my deepest gratitude to my advisor, University Professor Dr. Haas

Reinhard, for his support, patience, advice and direction while I researched this

thesis.

I am grateful to extend my appreciation to my colleagues and friends in MSc

Program “Renewable Energy in Central and Eastern Europe” for wonderful time

spent together.

I would also like to thank Daneco Impianti srl and Eggersman Anlagenbau GmbH

for their helpful suggestions and valuable discussions.

Finally, and most importantly, I would not have been able to complete this work

without the understanding of my family, my wife Nataša, daughter Lana and son

Luka, for whom I dedicate this piece of achievement.

56

References

Bichsel M., Glaude P., Burnham M.: A municipal collection, anaerobic digestion,

and end-product recuperation for residential food waste, Design Project,

McGill University, 2008

Binod K.: Dry Continuous anaerobic digestion of municipal solid wastes in

thermophilic conditions. Asian Institute of Technology, Thailand, 2008

Braber K.: Anaerobic digestion of municipal solid waste: a modern waste disposal

option on the verge of breakthrough. Biomass and Bioenergy, 9, 1995

Brandle Group Inc.: Anaerobic Digestion Feasibility Study, 2010

García-Heras, J.L.: Reactor sizing, process kinetics, and modelling of anaerobic

digestion of complex wastes. In: Biomethanization of the Organic Fraction of

Municipal Solid Wastes (edited by J. Mata-Alvarez), London: IWA Publishing,

2003

Evans G.: Biowaste and biological waste treatment. The Cromwell press ISBN: 1-

902916-08.05, 2001

Köttner M: Dry Fermentation – a new method for biological treatment. Article from

Internet, 2002

Institute of Wastes Management (IWM): Anaerobic digestion, a detailed report on

AD of MSW , 2001

Management (IWM) AD working group for IWM

Monnet F.: An Introduction to Anaerobic Digestion of Organic Wastes. Remade

Scotland, Final Report, 2003

RISE-AT.: Review of Current Status of Anaerobic Digestion Technology for

Treatment of Municipal Solid Waste. Retrieved on June 25, 2007. Chiang Mai

University, Institute of Science and Technology Research and Development.,

2007

57

Annex 1

LIST OF CALCULATION TABLES

Table 10.1 Building Works costs calculation

MSW 50 100 150 200 50 100 150 200

Organic (50%) 25 50 75 100 25 50 75 100

Parameter Unit kt/a kt/a kt/a kt/a kt/a kt/a kt/a kt/a

0. Working capacity

0.1 Working days per year

0.1.1 Mehanical treatment days 312 312 312 312 312 312 312 312

0.1.2 Biological treatment days 365 365 365 365 365 365 365 365

0.2 Working hours per day

0.2.1 Mehanical treatment hours 10 10 10 10 10 10 10 10

0.2.2 Biological treatment hours 24 24 24 24 24 24 24 24

0.3 Input plant capacity t/h 16 32 48 64 16 32 48 64

0.4 Number of processing lines No. 1 1 2 2 1 1 2 2

1. Investment price building works

1.1. Mechanical pretreatment plant incl.SRF Production and receivement pit € * 106

1,26 1,82 2,38 2,59 1,26 1,82 2,38 2,59

Surface m2

1.800 2.600 3.400 3.700 1.800 2.600 3.400 3.700

Price €/m2

700,00 700,00 700,00 700,00 700,00 700,00 700,00 700,00

1.2. Pretreatment for biological treatment plant incl. Dewatering € * 106

0,35 0,49 0,70 1,05 0,00 0,00 0,00 0,00

Surface m2

500 700 1.000 1.500

Price €/m2

700,00 700,00 700,00 700,00

1.3. Biological treatment € * 106

1,10 1,98 2,64 3,08 1,20 2,10 3,60 5,70

Surface m2

2.000 3.500 6.000 9.500

Price €/m2

600,00 600,00 600,00 600,00

1.4. Intensive Maturation plant (Tunnel) € * 106

0,45 0,91 1,36 1,82 0,45 0,91 1,36 1,82

Surface m2

908 1.815 2.723 3.630 908 1.815 2.723 3.630

Price €/m2

500,00 500,00 500,00 500,00 500,00 500,00 500,00 500,00

1.5. Post Maturation plant (open) € * 106

Surface m2

Price €/m2

1.6. Refinement plant € * 106

Surface m2

Price €/m2

1.7. Biogas cogeneration plant incl. gas cleaning € * 106

0,0900 0,1800 0,2400 0,3300 0,0900 0,1800 0,2400 0,3300

Surface m2

150 300 400 550 150 300 400 550

Price €/m2

600,00 600,00 600,00 600,00 600,00 600,00 600,00 600,00

Investment building works € * 106

3,25 5,38 7,32 8,87 3,00 5,01 7,58 10,44

Estimating Allowance (10%) € * 106

0,33 0,54 0,73 0,89 0,30 0,50 0,76 1,04

Total Investment building works € * 106

3,58 5,92 8,05 9,75 3,30 5,51 8,34 11,48

Per Ton Investment Costs Building Works €/t 71,58 59,15 53,69 48,76 66,08 55,08 55,60 57,39

LAND ACQUSITION COSTS

MSW 50 100 150 200 50 100 150 200

Organic (50%) 25 50 75 100 25 50 75 100


Necessary surface m2 5.692 9.304 12.996 16.288 7.772 13.144 20.036 27.808

Price €/m2 150 150 150 150 150 150 150 150

TOTAL INVESTMENT € 853.800 1.395.600 1.949.400 2.443.200 1.165.800 1.971.600 3.005.400 4.171.200

Capacity Capacity

Capacity

ANAEROBIC DIGESTION DRY FERMENTATION

Capacity


58

Table 10.2 Electro-mechanical costs calculation

MSW 50 100 150 200 50 100 150 200

Organic (50%) 25 50 75 100 25 50 75 100


0. Working capacity

0.1 Working days per year

0.1.1 Mehanical treatment days 312 312 312 312 312 312 312 312

0.1.2 Biological treatment days 365 365 365 365 365 365 365 365

0.2 Working hours per day

0.2.1 Mehanical treatment hours 10 10 10 10 10 10 10 10

0.2.2 Biological treatment hours 24 24 24 24 24 24 24 24

0.3 Input plant capacity t/h 16 32 48 64 16 32 48 64

0.4 Number of processing lines No. 1 1 2 2 1 1 2 2

1. Investment price electro-mechanical works

1.1. Mechanical pretreatment plant incl.RDF Production and receivement pit € * 106

4,06 5,34 7,23 8,46 4,06 5,34 7,23 8,46

Preshredder € * 106

0,30 0,40 0,60 0,80 0,30 0,40 0,60 0,80

Final Shredder € * 106

0,30 0,40 0,70 0,80 0,30 0,40 0,70 0,80

Screen € * 106

0,40 0,60 0,70 0,80 0,40 0,60 0,70 0,80

Air Separator € * 106

0,20 0,30 0,40 0,50 0,20 0,30 0,40 0,50

Magnets € * 106

0,03 0,04 0,05 0,06 0,03 0,04 0,05 0,06

Eddy Current € * 106

0,08 0,10 0,13 0,15 0,08 0,10 0,13 0,15

Chain Conveyors € * 106

0,20 0,30 0,40 0,50 0,20 0,30 0,40 0,50

Belt Conveyors € * 106

0,60 0,75 1,00 1,20 0,60 0,75 1,00 1,20

Air treatment € * 106

0,30 0,40 0,55 0,65 0,30 0,40 0,55 0,65

Steel structure € * 106

0,40 0,50 0,70 0,80 0,40 0,50 0,70 0,80

Electrical installations € * 106

0,45 0,65 0,75 0,80 0,45 0,65 0,75 0,80

Instrumentation and control system € * 106

0,20 0,25 0,35 0,40 0,20 0,25 0,35 0,40

Installation and commissioning € * 106

0,60 0,65 0,90 1,00 0,60 0,65 0,90 1,00


1,60 2,00 2,40 3,00 0,00 0,00 0,00 0,00

1.3. Biological treatment (AD/Dry Fermentation) € * 106

3,00 4,20 5,50 7,00 2,40 4,00 5,00 6,00

(incl. Main and Post-Processing Equipment)


1,25 2,50 3,75 5,00 1,50 3,00 4,50 6,00




1,20 1,95 2,80 3,50 0,90 1,50 2,40 3,00

1.8. Plant Vehicles € * 106

0,60 0,60 0,73 0,73 0,73 0,73 0,82 0,86

Investment Electro-Mechanical works € * 106

11,11 15,99 21,68 26,96 8,86 13,84 19,13 23,46

Estmating Allowance (10%) € * 106 1,11 1,60 2,17 2,70 0,89 1,38 1,91 2,35

Investment Electro-Mechanical works € * 106

12,22 17,59 23,85 29,66 9,74 15,22 21,04 25,81

Per Ton Investment Costs Electro-mechanic Works €/t 244,31 175,89 158,99 148,28 194,81 152,24 140,29 129,03


Capacity Capacity

59

Table 10.3 Amortisation and financing costs calculation

WASTE DISPOSAL ON AN ANNUAL BASIS: 50.000,00 tons WASTE DISPOSAL ON AN ANNUAL BASIS: 50.000,00 tons

AMORTIZATION PERIOD 15,00 years AMORTIZATION PERIOD 15,00 years

Years of Financing (equal to the duration of concession) 15,00 Years of Financing (equal to the duration of concession) 15,00

I=level of interest 6,00% I=level of interest 6,00%

Va=plant value € 16.648.425,00 Va=plant value € 14.210.425,00

i=I/2 0,030 i=I/2 0,030

1+i 1,030 1+i 1,030

1/(1+i) 0,970873786 1/(1+i) 0,970873786

n=semi-annual instalments 30 n=semi-annual instalments 30

Semi-annual amortization instalments 849.390 Semi-annual amortization instalments 725.005

Annual amortization instalments € 1.698.780,62 Annual amortization instalments € 1.450.010,72






i=I/2 0,030 i=I/2 0,030

1+i 1,030 1+i 1,030

1/(1+i) 0,970873786 1/(1+i) 0,970873786


Semi-annual amortization instalments 1.270.372 Semi-annual amortization instalments 1.158.334







i=I/2 0,030 i=I/2 0,030

1+i 1,030 1+i 1,030

1/(1+i) 0,970873786 1/(1+i) 0,970873786









i=I/2 0,030 i=I/2 0,030

1+i 1,030 1+i 1,030

1/(1+i) 0,970873786 1/(1+i) 0,970873786




€ 22,03

FINANCING

€ 21,15

FINANCING

€ 23,03

FINANCING

€ 21,35

DRY FERMENTATION

FINANCING

€ 29,00

FINANCING

€ 23,17

FINANCING

FINANCING

€ 33,98

ANAEROBIC DIGESTION

FINANCING

€ 25,41

60

Table 10.4 O & M summary costs calculation

MSW 50 100 150 200 50 100 150 200

Organic (50%) 25 50 75 100 25 50 75 100


1. El. Energy Costs €/y 537.903 803.610 1.197.608 1.480.590 413.008 639.675 981.353 1.202.210

2. Total personnel cost €/y 725.120 799.280 873.440 947.600 799.280 947.600 1.095.920 1.244.240

3. Maintenance Costs €/y 413.250 575.500 779.000 945.000 333.250 483.000 686.000 833.000

4. Mobile wehicles Maintenance Costs €/y 175.740 187.830 240.090 264.270 269.340 293.520 377.640 440.940

5. Analysis €/y 60.000 60.000 60.000 60.000 60.000 60.000 60.000 60.000

6. Unforseen (10%) €/y 191.201 242.622 315.014 369.746 187.488 242.380 320.091 378.039

7. Estimating Allowance (10%) €/y 191.201 242.622 315.014 369.746 187.488 242.380 320.091 378.039

TOTAL O & M Costs €/y 2.294.415 2.911.464 3.780.165 4.436.952 2.249.853 2.908.554 3.841.095 4.536.468

O & M Costs per input ton €/t 45,89 29,11 25,20 22,18 45,00 29,09 25,61 22,68

Capacity Capacity


Table 10.5 El. Energy costs calculation

MSW 50 100 150 200 50 100 150 200

Organic (50%) 25 50 75 100 25 50 75 100

Unit kt/a kt/a kt/a kt/a kt/a kt/a kt/a kt/a

1. El. Energy Installed

1.1. Mechanical pretreatment plant incl.RDF Production and receivement pit kW 1.200 1.600 2.500 2.900 1.200 1.600 2.500 2.900

% of use % 0,70 0,70 0,70 0,70 0,70 0,70 0,70 0,70

Working hours per year h 3.120 3.120 3.120 3.120 3.120 3.120 3.120 3.120

Total kWh consumed kWh 2.620.800 3.494.400 5.460.000 6.333.600 2.620.800 3.494.400 5.460.000 6.333.600

1.2. Pretreatment for biological treatment plant incl. Dewatering kW 500 700 900 1.200 0 0 0 0

% of use % 0,70 0,70 0,70 0,70

Working hours per year h 3.120 3.120 3.120 3.120

Total kWh consumed kWh 1.092.000 1.528.800 1.965.600 2.620.800 0 0 0 0

1.3. Biological treatment (AD/Dry Fermentation) kW 55 75 120 150 75 150 225 300

% of use % 0,50 0,50 0,50 0,50 0,50 0,50 0,50 0,50


Total kWh consumed kWh 228.250 311.250 498.000 622.500 187.500 375.000 562.500 750.000

1.4. Intensive Maturation plant (Tunnel) kW 375 750 1.125 1.500 375 750 1.125 1.500

% of use % 0,35 0,35 0,35 0,35 0,35 0,35 0,35 0,35


Total kWh consumed kWh 1.089.375 2.178.750 3.268.125 4.357.500 1.089.375 2.178.750 3.268.125 4.357.500

1.5. Post Maturation plant (open) kW

% of use %

Working hours per year h

Total kWh consumed kWh

1.6. Refinement plant kW

% of use %

Working hours per year h

Total kWh consumed kWh

1.7. Biogas cogeneration plant incl. gas cleaning kW 120 180 270 300 80 120 180 200

% of use % 0,35 0,35 0,35 0,35 0,35 0,35 0,35 0,35


Total kWh consumed kWh 348.600 522.900 784.350 871.500 232.400 348.600 522.900 581.000

Total El. Energy Consumed kWh/y 5.379.025 8.036.100 11.976.075 14.805.900 4.130.075 6.396.750 9.813.525 12.022.100

El. Energy Cost €/kWh 0,1 0,1 0,1 0,1 0,1 0,1 0,1 0,1

Total El Energy Costs €/y 537.903 803.610 1.197.608 1.480.590 413.008 639.675 981.353 1.202.210

Capacity Capacity


61

Table 10.6 Personal costs calculation Anaerobic Digestion

First ShiftSecond

ShiftSingle Total Unit Cost Total Cost

Plant Manager 1 1 € 60.000,00 € 60.000,00

Weight Bridge attendant - admin. 1 1 2 € 35.000,00 € 70.000,00

Receivement pit - plant loading 1 1 2 € 35.000,00 € 70.000,00

Wheeled Loader Operator - Intensive maturation 1 1 2 € 36.000,00 € 72.000,00

Process Control operators for mechanical treatment 1 1 2 € 45.000,00 € 90.000,00

Process Control operators for biological treatment 1 1 2 € 45.000,00 € 90.000,00

Responsible for eco environment 1 1 € 36.000,00 € 36.000,00

Maintenance 2 2 4 € 36.000,00 € 144.000,00

Jolly 1 1 2 € 36.000,00 € 72.000,00

Total 8 8 2 18 € 704.000,00

Bonuses - Extra allowances - Overtime € 21.120,00

TOTAL COST of PERSONNEL € 725.120,00

First ShiftSecond


Plant Manager 1 1 € 60.000,00 € 60.000,00







Maintenance 3 3 6 € 36.000,00 € 216.000,00

Jolly 1 1 2 € 36.000,00 € 72.000,00

Total 9 8 2 19 € 776.000,00



First ShiftSecond


Plant Manager 1 1 € 60.000,00 € 60.000,00







Maintenance 4 4 8 € 36.000,00 € 288.000,00

Jolly 1 1 2 € 36.000,00 € 72.000,00

Total 10 9 2 21 € 848.000,00



First ShiftSecond


Plant Manager 1 1 € 60.000,00 € 60.000,00







Maintenance 5 5 10 € 36.000,00 € 360.000,00

Jolly 1 1 2 € 36.000,00 € 72.000,00

Total 11 10 2 23 € 920.000,00



Extra allowances nightshift - Overtime - 3%

PERSONNEL COSTS PLANT CAPACITY 100.000 t/y


TASK

ANAEROBIC DIGESTION


TASK

PRESENCE COST ( euro )


TASK






TASK


62

Table 10.7 Personal costs calculation Dry Fermentation

First ShiftSecond


Plant Manager 1 1 € 60.000,00 € 60.000,00



Wheeled Loader Operator 2 2 4 € 36.000,00 € 144.000,00




Maintenance 2 2 4 € 36.000,00 € 144.000,00

Jolly 1 1 2 € 36.000,00 € 72.000,00

Total 9 9 2 20 € 776.000,00



First ShiftSecond


Plant Manager 1 1 € 60.000,00 € 60.000,00







Maintenance 3 3 6 € 36.000,00 € 216.000,00

Jolly 1 1 2 € 36.000,00 € 72.000,00

Total 11 10 2 23 € 920.000,00



First ShiftSecond


Plant Manager 1 1 € 60.000,00 € 60.000,00







Maintenance 4 4 8 € 36.000,00 € 288.000,00

Jolly 1 1 2 € 36.000,00 € 72.000,00

Total 13 12 2 27 € 1.064.000,00


TOTAL COST of PERSONNEL € 1.095.920,00

First ShiftSecond


Plant Manager 1 1 € 60.000,00 € 60.000,00







Maintenance 5 5 10 € 36.000,00 € 360.000,00

Jolly 1 1 2 € 36.000,00 € 72.000,00

Total 15 14 2 31 € 1.208.000,00


TOTAL COST of PERSONNEL € 1.244.240,00



TASK




TASK





TASK


DRY FERMENTATION


TASK


63

Table 10.8 Maintenance costs calculation

MSW 50 100 150 200 50 100 150 200

Organic (50%) 25 50 75 100 25 50 75 100

Unit kt/a kt/a kt/a kt/a kt/a kt/a kt/a kt/a

1. Investment Costs

1.1. Mechanical pretreatment plant incl.RDF Production and receivement pit € * 106

4,06 5,34 7,23 8,46 4,06 5,34 7,23 8,46

% for Maintenance per year % 0,05 0,05 0,05 0,05 0,05 0,05 0,05 0,05

Total Maintenance cost €/y 202.750 267.000 361.500 423.000 202.750 267.000 361.500 423.000


1,60 2,00 2,40 3,00 0,00 0,00 0,00 0,00


Total Maintenance cost €/y 48.000 60.000 72.000 90.000 0 0 0 0

1.3. Biological treatment (AD/Dry Fermentation) € * 106

3,00 4,20 5,60 6,90 2,60 4,20 6,40 8,00




1,25 2,50 3,75 5,00 1,25 2,50 3,75 5,00




% for Maintenance per year %

Total Maintenance cost €/y


% for Maintenance per year %

Total Maintenance cost €/y


1,20 1,95 2,80 3,50 0,80 1,30 1,90 2,40



Total Maintenance Costs per year €/y 413.250 575.500 779.000 945.000 333.250 483.000 686.000 833.000


Capacity Capacity

64

Table 10.9 Mobile Vehicle costs calculation Anaerobic Digestion

Total O&M

WorkingSpecific

ConsumptionFuel Costs Purchased Costs

Maintenance

PercentageTotal cost

Hours per year Litters 1,3 € % €

Wheeled Loader 2.500 15 € 48.750,00 € 130.000,00 12% € 15.600,00 64.350,00€

Turner - 32 € - € - 12% € - -€

Grab Loader 1.500 15 € 29.250,00 € 200.000,00 12% € 24.000,00 53.250,00€

Truck - 12 € - € - 12% € - -€

Forklift 600 8 € 6.240,00 € 70.000,00 12% € 8.400,00 14.640,00€

Mobile Shredder 500 30 € 19.500,00 € 200.000,00 12% € 24.000,00 43.500,00€

TOTAL € 103.740,00 € 600.000,00 € 72.000,00 175.740,00€

Total O&M

WorkingSpecific


Maintenance



Wheeled Loader 3.120 15 € 60.840,00 € 130.000,00 12% € 15.600,00 76.440,00€

Turner - 32 € - € - 12% € - -€

Grab Loader 1.500 15 € 29.250,00 € 200.000,00 12% € 24.000,00 53.250,00€

Truck - 12 € - € - 12% € - -€

Forklift 600 8 € 6.240,00 € 70.000,00 12% € 8.400,00 14.640,00€

Mobile Shredder 500 30 € 19.500,00 € 200.000,00 12% € 24.000,00 43.500,00€

TOTAL € 115.830,00 € 600.000,00 € 72.000,00 187.830,00€

Total O&M

WorkingSpecific


Maintenance



Wheeled Loader 5.000 15 € 97.500,00 € 260.000,00 12% € 31.200,00 128.700,00€

Turner - 32 € - € - 12% € - -€

Grab Loader 1.500 15 € 29.250,00 € 200.000,00 12% € 24.000,00 53.250,00€

Truck - 12 € - € - 12% € - -€

Forklift 600 8 € 6.240,00 € 70.000,00 12% € 8.400,00 14.640,00€

Mobile Shredder 500 30 € 19.500,00 € 200.000,00 12% € 24.000,00 43.500,00€

TOTAL € 152.490,00 € 730.000,00 € 87.600,00 240.090,00€

Total O&M

WorkingSpecific


Maintenance



Wheeled Loader 6.240 15 € 121.680,00 € 260.000,00 12% € 31.200,00 152.880,00€

Turner - 32 € - € - 12% € - -€

Grab Loader 1.500 15 € 29.250,00 € 200.000,00 12% € 24.000,00 53.250,00€

Truck - 12 € - € - 12% € - -€

Forklift 600 8 € 6.240,00 € 70.000,00 12% € 8.400,00 14.640,00€

Mobile Shredder 500 30 € 19.500,00 € 200.000,00 12% € 24.000,00 43.500,00€

TOTAL € 176.670,00 € 730.000,00 € 87.600,00 264.270,00€

VEHICLE

Fuel Consumption Maintenance

VEHICLE

PLANT VEHICLES MANAGEMENT PLANT CAPACITY 200.000 t/y


ANAEROBIC DIGESTION



VEHICLE



VEHICLE


65

Table 10.10 Mobile Vehicle costs calculation Dry Fermentation

Total O&M

WorkingSpecific


Maintenance



Wheeled Loader 5.000 15 € 97.500,00 € 260.000,00 12% € 31.200,00 128.700,00€

Turner - 32 € - € - 12% € - -€

Grab Loader 3.000 15 € 58.500,00 € 200.000,00 12% € 24.000,00 82.500,00€

Truck - 12 € - € - 12% € - -€

Forklift 600 8 € 6.240,00 € 70.000,00 12% € 8.400,00 14.640,00€

Mobile Shredder 500 30 € 19.500,00 € 200.000,00 12% € 24.000,00 43.500,00€

TOTAL € 181.740,00 € 730.000,00 € 87.600,00 269.340,00€

Total O&M

WorkingSpecific


Maintenance



Wheeled Loader 6.240 15 € 121.680,00 € 260.000,00 12% € 31.200,00 152.880,00€

Turner - 32 € - € - 12% € - -€

Grab Loader 3.000 15 € 58.500,00 € 200.000,00 12% € 24.000,00 82.500,00€

Truck - 12 € - € - 12% € - -€

Forklift 600 8 € 6.240,00 € 70.000,00 12% € 8.400,00 14.640,00€

Mobile Shredder 500 30 € 19.500,00 € 200.000,00 12% € 24.000,00 43.500,00€

TOTAL € 205.920,00 € 730.000,00 € 87.600,00 293.520,00€

Total O&M

WorkingSpecific


Maintenance



Wheeled Loader 10.000 15 € 195.000,00 € 350.000,00 12% € 42.000,00 237.000,00€

Turner - 32 € - € - 12% € - -€

Grab Loader 3.000 15 € 58.500,00 € 200.000,00 12% € 24.000,00 82.500,00€

Truck - 12 € - € - 12% € - -€

Forklift 600 8 € 6.240,00 € 70.000,00 12% € 8.400,00 14.640,00€

Mobile Shredder 500 30 € 19.500,00 € 200.000,00 12% € 24.000,00 43.500,00€

TOTAL € 279.240,00 € 820.000,00 € 98.400,00 377.640,00€

Total O&M

WorkingSpecific


Maintenance



Wheeled Loader 13.000 15 € 253.500,00 € 390.000,00 12% € 46.800,00 300.300,00€

Turner - 32 € - € - 12% € - -€

Grab Loader 3.000 15 € 58.500,00 € 200.000,00 12% € 24.000,00 82.500,00€

Truck - 12 € - € - 12% € - -€

Forklift 600 8 € 6.240,00 € 70.000,00 12% € 8.400,00 14.640,00€

Mobile Shredder 500 30 € 19.500,00 € 200.000,00 12% € 24.000,00 43.500,00€

TOTAL € 337.740,00 € 860.000,00 € 103.200,00 440.940,00€

VEHICLE



VEHICLE



DRY FERMENTATION



VEHICLE



VEHICLE

comparative economical analysis of biogas …

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