Comparative casestudy of biogas utilization from livestock manure in vietnam (focussing on CO2 balance)

At household scale, biogas is utilized mostly for cooking and such tons of greenhouse gas can be reduced from one household per year, mostly from correctlivestock manure management and f

TRƯƠNG THỊ KIM DUNG

COMPARATIVE CASE STUDY OF BIOGAS UTILIZATION FROM

LIVESTOCK MANURE IN VIETNAM

(FOCUSSING ON CO2 BALANCE) Field: waste management and contaminated site treatment

MASTER THESIS

Supervisor:

Dr.-Ing Christoph Wünsch

Dresden, September, 2011

Firstly I would like to thank to the Hanoi University of Science, VietnamNational University and Techniche Universtät Dresden, Institute of Waste Managementand Contaminated Site Treatment, whose have established a good study program for us

to learn a good new field of environment

I would like to thanks to Prof Bernd Bilitewski, Prof Nguyen Thi Diem Trangand Dr Hoang Van Ha, whose always keep an eye on our study and help us so much

My sincerely thanks to my supervisor Dr Christoph Wünsch, Dipl Veit

Grundmann , who guide and help me hold-heartedly during the time I did the thesis And I also want to thanks to Dr Catalin Stephan and Dipl.Hoang Mai I still rememberour discussion, small parties as well as your encouragements It helps me more self-confident in my ability

Finally I want to thanks so much to my family You are my motivation to

overcome difficulties in my life

From 2003 Livestock Production Department under Ministry of Agriculture and Rural Development - MARD cooperates with Netherlands Development Organization– SNV to deploy of domestic biogas program for livestock production in rural area

The program not only solve environment problems in terms of pollution andimprove rural life quality, it also contributes to greenhouse gas reduction considerably

At household scale, biogas is utilized mostly for cooking and such tons of greenhouse

gas can be reduced from one household per year, mostly from correctlivestock manure management and fossil fuel substitution

At farm scale, biogas can be utilized for electricity generation, thousands KWh

of electricity can be produced and such thousand tons of greenhouse gas can bereduced per farm per year

It should be encouraged to apply this treatment method for all kinds of livestock

of the country The greenhouse gas emission reduction will be much more significantly,contribute to meet the aim of the Kyoto Protocol “to achieve stabilization ofatmospheric concentration of greenhouse gases at a level that would prevent dangerousanthropogenic interference with the climate system” that Vietnam signed in

INTRODUCTION 6

I BACKGROUND 1

1.1 Greenhouse effects and climate change 1

1.1.1 Greenhouse effects 1

1.1.2 Climate change 3

1.2 Greenhouse gas emission situation in Vietnam 7

1.3 Livestock growing situation in Vietnam 12

II OVERVIEW ON BIOGAS 16

2.1 Scientific theory of anaerobic digestion (biogas formation) 16

2.2 Composition of biogas 19

2.3 Substrates for anaerobic digestion 22

III BIOGAS PROJECT IN VIETNAM 22

3.1 Project overview 22

3.2 Technology of anaerobic digester used in the project 23

3.2.1 Structure of the anaerobic digester 23

3.2.2 Operation of the biogas plant 25

3.2.3 Treatment efficiency of biogas plants 26

3.3 Utilization of outputs from biogas plants 27

3.3.1 Utilization of biogas 27

IV CASE STUDY 35

4.1 Project scenario 35

4.2 Methodology 36

4.2.1 GHG reduction from manure management 36

3.2.2 GHG reduction from the fossil fuel substitution in thermal application or electricity generation 42

3.2.3 GHG reduction from chemical fertilizer substitution by bio-slurry 46

4.3 Calculation and results 48

4.3.1 GHG reduction at household scale 48

4.3.2 GHG reduction at farm scale 64

4.4 Outlook 67

IV CONCLUSION 71

Landfill gasMinistry of agriculture and rural developmentNon-methane volatile organic compoundsThe Netherlands development organizationVolatile solid

United Nations framework Convention on Climate Change

LIST OF TABLES

Table 1: National greenhouse gas emission inventory by sector of Vietnam in 2000 7

Table 2: greenhouse gas emission from agriculture sector 8

Table 3: total primary energy consumption by type of energy 9

Table 4: GHG emission from fuel combustion by type of fuel in 2000 10

Table 5: GHG emission from fuel combustion by sub-sector 10

Table 6: GHG emission from fuel combustion by type of gas 11

Table 7: Livestock population growth (thousands) 13

Table 8: livestock and milk production, million metric tons 14

Table 9: total livestock waste (solid) generation in 2006 16

Table 10: Environmental requirements 19

Table 11: Biogas composition 19

Table 12: Biogas composition compared with natural gas 20

Table 13: General energy characteristics of biogas 21

Table 14: Treatment efficiency of biogas plants 26

Table 15: Limited parameters for surface water quality according to the National technical regulation 2008 27

Table 16: comparative values of biogas and other fuels 28

Table 17: consumption of biogas and kerosene fuel in lighting according to the experience of the Institute of Energy 30

Table 18: Nutrient concentrations in the bio-slurry 32

Table 19: concentration of some heavy metals in bio-slurry 33

Table 20: nutrient contents in compost fertilizer made from bio-slurry and agricultural waste 34

Table 21: benefits from application of bio-slurry in agriculture in some provinces 35

Table 22: input parameters for methane emission calculation from the baseline scenario (unrecoverable anaerobic lagoon) 49

Table 23 input parameters for indirect nitrogen oxide emission calculation from thebaseline scenario (unrecoverable anaerobic lagoon) and project scenario (biogas plant)51

Table 24: result of GHG emission reduction from manure management 52

Table 25: combustion efficiencies of combustion equipments with different fuels 53

Table 26: GHG emission factor of coal 54Table 27: input parameters for GHG emission reduction calculation from fuel

substitution in thermal application for at household scale 54

Table 28: GHG reduction results for a household growing 6 pigs 56Table 29: Emission factors for stationary combustion in the residential and

agricultural/forestry/fishing/farms 58Table 30: Results of GHG reduction in case different fossil fuel used in absence of the

project 59

Table 31: GHG emission reduction according to population of livestock (pig) 61

Table 32: the utilized biogas yield according to population of livestock (pig) 63Table 33: GHG reduction for a farm growing 100 pigs with utilization of biogas for

electricity generation 66Table 34: input parameters for GHG emission reduction calculation from biogas

destruction in the outlook 67Table 35: The result of GHG emission reduction from biogas destruction in the outlook68

Table 36: input parameters for GHG emission reduction calculation from nitrogen

oxide emission reduction in the outlook 68Table 37: The result of GHG emission reduction from nitrogen emission reduction in

the outlook 69Table 38: The result of GHG emission reduction from manure management in the

Table 39: input parameters for GHG emission reduction calculation fuel substitution in

thermal application in the outlook 70Table 40: GHG emission reduction calculation fuel substitution in thermal application

in the outlook 70

Table 41: Total GHG emission reduction in the outlook 71

LIST OF CHARTS

Chart 1: GHG reduction for a household growing 6 pigs with utilization of biogas for

cooking purpose 57Chart 2: GHG reduction in case different fossil fuel used in the absence of the project60

Chart 3: GHG emission reduction according to number of livestock 62Chart 4: GHG reduction for a farm growing 100 pigs with utilization of biogas for

electricity generation 66

LIST OF FIGURES

Figure 1: The greenhouse effect principle 3

Figure 2: changes in temperature, sea level and Northern Hemisphere snow cover 5

Figure 3: National greenhouse gas emission inventory by sector of Vietnam in 2000 8

Figure 4: Growth rate of pork production 15

Figure 5: the anaerobic digestion process 18

Figure 6: Types of fixed dome biogas plant used in the project are KT1 and KT2 24

Figure 7: two limit stages of fixed dome plant 25

Figure 8: diagram of biogas burner 27

Figure 9: Structure of biogas lamp 29

Figure 10: A biogas water boiler device 31

Figure 11: Project scenario 35

Figure 12: baseline scenario boundary of GHG reduction source: biogas destruction 38 Figure 13: project scenario boundary of GHG reduction source: biogas destruction .39

Figure 14: Baseline scenario boundary of GHG reduction source: fossil fuel substitution in thermal application 43

Figure 15: project scenario boundary of GHG reduction source: fossil fuel substitution in thermal application 43

Figure 16: Baseline scenario boundary of GHG reduction source: fossil fuel substitution in electricity generation 44

Figure 17: Project scenario boundary of GHG reduction source: fossil fuel substitution in electricity generation 45

Figure 18: baseline scenario boundary of GHG reduction source: chemical fertilizer substitution 47

Figure 19: project scenario boundary of GHG reduction source: chemical fertilizer substitution 47

Above the environment pollution problems from the rapid growing in livestockproduction without livestock manure treatment, the situation of lack of energy, and theoveruse of chemical fertilizer production for crop production From 2003 LivestockProduction Department under Ministry of Agriculture and Rural Development -MARD cooperates with Netherlands Development Organization – SNV to deploy ofdomestic biogas program to solve the short term of environment problems and alsohave the long term objective of improving the livelihood and quality of life of ruralfarmers in Vietnam

Until now there are more than 106000 biogas systems constructed in over 50 provincesnationwide, millions tons of livestock manure are treated There are also someevaluation reports on economical and social effects But there isn’t any detail reportevaluating on environmental effects, especially greenhouse gas reduction from thatproject

The aim of this research is the detail assessment of GHG emission balance fromlivestock manure treatment method by anaerobic digesters (biogas plants) in the project

to provide the reference data about the benefits of that project in term of GHG emissionbalance

is higher than it would be if direct heating by solar radiation were the only warming

mechanism” http://en.wikipedia.org/wiki/Greenhouse_effect

From 1827, Joseph Fourier recognized the importance of the greenhouse effectfor the Earth’s climate He emphasized that the atmosphere is relatively transparent tosolar radiation, but highly absorbent to thermal radiation and that this preferential

trapping is responsible for raising the temperature of the Earth’s surface [Isaac M Held, Brian J Sodden, 2000] “The natural greenhouse effect means the short-wave

energy from the sun is absorbed at the earth’s surface and reradiated in the form ofinfrared Chart (long wave) radiation The greenhouse gas (some of low concentrategases in atmospheric notably CO2, CH4, NOx, CO, etc.) absorb and emit long waveradiation The increase in the atmospheric concentration of GHG leads to anincremental absorption and emission of long-wave radiation All of them would result

in a warming of the lower atmosphere and the surface of earth This effect is referred as

“greenhouse effect” Human beings and most other living creatures can not survivewithout Natural greenhouse effect The greenhouse effect keeps the temperature ofbiosphere stable and filters some harmful radiations and hence protects the ecological

system” [Jia Xiaodong, 2009]

Because of influence from human activities, greenhouse gas is increased,leading to enhanced greenhouse effect and climate change Expressions of the climatechange include temperature change in global scale, sea level rise, precipitation change

and the increase of extreme weather events [IPCC, 2008].

Figure 1: The greenhouse effect principle

Source: http://en.wikipedia.org/wiki/Greenhouse_effect

1.1.2 Climate change

* Definitions of climate change

The definitions of climate change are different of the Intergovernmental Panel

on Climate Change (IPCC) and the United Nations Framework Convention on ClimateChange (UNFCCC)

According to IPCC, “the climate change refers to a change in the state of theclimate that can be identified (e.g using statistical tests) by changes in the mean and/orthe variability of it property, and that persists for an extended period, typically decades

or longer It refers to any change in climate over time, whether due to natural

The climate change according to UNFCCC is a change of climate that iscontributed directly or indirectly to human activity that alters the composition of theglobal atmosphere and that is in addition to natural climate variability observed over

comparable time periods [IPCC, 2008]

* Climate change over the world

Global warming is now evident from increases of global air, ocean temperaturesand widespread melting of ice and snow and rising global sea level

According to the instrument record of global surface temperature from 1850, the eleven

years of the rank from 1995 to 2006 is the warmest years [IPCC, 2008].

The linear trend of the global average temperature in the same long period of

100 years from 1906 to 2005 is 0.74 [0.56 to 0.92], higher than the 100-year periodfrom 1901 to 2000 that is 0.6 [0.4 to 0.8] The linear warming trend over the 50 yearsfrom 1956 to 2005 (0.13 [0.10 to 0.16]°C per decade) is nearly twice higher than the

period of 100 years from 1906 to 2005 [IPCC, 2008]

Figure 2: changes in temperature, sea level and Northern Hemisphere snow cover

Source: [IPCC, 2008]

The temperature increase has taken place at global scale The increase rate oftemperature in Acrtic is almost twice higher than the global average rate in the past 100years Land regions are warmed faster than the oceans

The increase of sea level is correlative with warming of the earth (figure 2) Thesea level rose have been clearer in recent years The global sea level rise rate from

1993 to 2003 is 3.1 [2.4 to 3.8] mm per year that is higher than the rate of 1.8 [1.3 to

2.3] of the period from 1961 to 2003 [IPCC, 2008] That increase is contributed by the

thermal expansion of the oceans (57%), by the decreases in glaciers and ice caps (28%)

and losses from polar ice sheets (15%) [IPCC, 2008].

The decreases of snow and ice are also relative with warming of the earth(figure 2) The annual average sea ice in Arctic has shrunken about 2.7 [2.1 to 3.3]%per decade, and this number is higher in summers of 7.4 [5.0 to 9.8]% per decade.Glaciers and snow in mountains in both hemispheres also have declined The frozendground extent in the Northern Hemisphere has decreased about 7% since 1900 Fromthe 1980s up to now, the temperature at the top of the permafrost layer in Arctic

increased by up 3°C [IPCC, 2008].

The precipitate also changed much in many regions “Globally, the area affected

by drought has likely increased since the 1970s” [IPCC, 2008]

The extreme changes of the weather have happened frequently over the last 50years: “it is very likely that cold days, cold nights and frosts have become less frequentover most land areas, while hot days and hot nights have become more frequent It islikely that heat waves have become more frequent over most land areas It is likely thatfrequency of heavy precipitation events has increased over most areas And it is likelythat the incidence of extreme high sea level has increased at abroad range of sites

worldwide since 1975”[IPCC, 2008].

The average temperature in the Northern Hemisphere during the second half ofthe 20th century is higher than any 50-year period in the last 500 years and is the

highest in at least past 1300 years [IPCC, 2008].

* Climate change in Vietnam

Vietnam is one of the countries that are suffered mostly of climate change.According to recent studies in Vietnam, the average temperature has increased about0.1 10C per decade The weather seems severer The temperature of beginning months

of the winter decreases but increases in months of the end of the winter Seasonalrainfall decreases in July and August and increases in September, October and

November The sea level has risen at average rate about 2.5 – 3 cm per decade Storms,floods and droughts have taken more frequently recent years.

Because of the climate change, the sea water level of Vietnam is forecasted to beraised by 33 cm in 2050 and 45 cm in 2070 And if the sea level increases up to 90 cm

in 2100, a huge area in the Red River Delta, north central coastal area and Cuu Long

delta area will be submerged under water [MARD, SNV, 2007].

1.2 Greenhouse gas emission situation in Vietnam

Vietnam has contributed around 151 million tons of CO2 equivalent in 2000 inwhich agriculture sector is the largest source (43.1%), then is from the energy sector(35.0 %) and at least from industrial sector (6.6 %) and from waste (5.3 %) as in thetable 1 and figure 3

Table 1: National greenhouse gas emission inventory by sector of Vietnam in 2000

Sector

Energy

Industrial processes

Agriculture

Land use, land-use

change and forestry

Waste

8

Table 3: total primary energy consumption by type of energy:

Unit: kilo tons of oil equivalent

Table 4: GHG emission from fuel combustion by type of fuel in 2000

Unit: thousand tons

Table 5: GHG emission from fuel combustion by sub-sector

Unit: thousand tons

10

Table 6: GHG emission from fuel combustion by type of gas

GHG emissionGas

Vietnam has been a part of UNFCCC and signed the Kyoto Protocol on 25th,

September 2002 with the aim “to achieve stabilization of atmospheric concentration of

greenhouse gases at a level that would prevent dangerous anthropogenic interference

with the climate system”

Related to the aim of greenhouse gas reduction in the Kyoto Protocol, Vietnam has

had a number of environment protection laws and regulations including:

 Environmental Protection Law No 52/2005/QH11 dated 29th November 2005

 Water Resources Law No 08/1998/QH10 dated 20th May 1998.

 Petroleum Law (1993) No 10/2008/QH12 dated 6th July 1993

(amended twice on 9th June 2000 and 3rd June 2008)

 Law on Minerals No 2/1996/QH9 dated 1st September 1996 (amended

on 27th June 2005)

 Law on Forest Protection and Development No 29/2004/QH11 dated

3rd December 2004 (replaces the 1991 Law on Forest Protection and

 Law on Safe and Efficient Use of Energy No 50/2010/QH12 dated 28th June

2010

Vietnam also has had the national strategies and programs related to GHGreduction The National Environment Protection strategy 2003 aims to apply of cleantechnologies, cleaner production processes and use of environment-friendly fuels andmaterials The National Target Program 2006 enforces on regulations on energyconservation and efficiency And the National Target Program 2008 to respond toclimate change, in which the development and implementation of GHG reductionoptions contributes an important role in this program Replace cooking coal by biogas

is one of options of the Government towards to reduce GHG emission

1.3 Livestock growing situation in Vietnam

Vietnam is on the trend of development, which the increasing growth rate in GDP

is stable around 6.5 percent from 1998 to 2003 Although the agriculture justcontributes 20% to of GDP in 2007, but Vietnam is still an agricultural country, most ofthe population lives based on agriculture production The livestock production

contributes 20% to agricultural GDP [General Statistic Office of Vietnam, 2007, 2008].

The main types of livestock are swine, cattle, buffalo and poultry The table 7 showsthe livestock production growth from 2000 to 2010, in which the pig population is mostand increase continuously fast from 20,194 to 26,701 thousands of heads

Table 7: Livestock population growth (thousands)

Year

20002001

200220032004200520062007

20082009

2010 (preliminary) Source: [General Statistic Office of Vietnam, 2007, 2008, 2010]

Vietnam is also one of countries which export mostly pork over the world (2.55million metric tons in 2008) The table 8 shows product productions from livestock, inwhich pork is the most significant contributor (71% of total livestock production)

Table 8: livestock and milk production, million metric tons

Figure 4: Growth rate of pork production

Source: [General Statistic Office of Vietnam, 2008]

Livestock production brings quiet high financial benefits to farmers, but it alsogenerates environmental problems The table 9 shows most of manure from livestock isnot treated properly, causes smell, water and soil pollution as well as greenhouse gasemission

Table 9: total livestock waste (solid) generation in 2006

Source: [Eastern research Group et al, 2010]

II OVERVIEW ON BIOGAS

2.1 Scientific theory of anaerobic digestion (biogas formation)

The anaerobic digestion is a complex process that can be divided up into four stages

of degradation: hydrolysis, acidogenesis, acetogenesis and methanation, under theinfluence of different kinds of microorganisms

Stage 1 - Hydrolysis: high-molecular compounds, like cellulose, proteins, andfats are cracked into lower-molecular compounds, like monosaccharide, amino

acids, fatty acids and water under the influence of enzymes of facultative andobligatorily anaerobic microorganisms.

The facultative anaerobic microorganisms use oxygen dissolved in water andcreate the low redox potential that necessary for obligatorily anaerobicmicroorganisms

Stage 2 - Acidogenesis: this stage is done by the acid-formingmicroorganisms, which degrade lower-molecular compounds from the firststage into short-chain organic acids, C1 – C5 molecules (e.g., butyric acid,propionic acid, acetate, and acetic acid), alcohols, hydrogen, and carbondioxide

Stage 3 – Acetogenesis: The products from acidogenic phase serve as substratefor other microorganisms In which, homo-acetogenic microorganismsconstantly convert exergonic H2 and CO2 to acetic acid for the next stepaccording to the following reaction:

Figure 5: the anaerobic digestion processThis process is biological, so any change in temperature, substrates or substrateconcentration can lead to shutdown the gas production The following table is theoptimal environment parameters for an optimum fermentation process.

Table 10: Environmental requirements

19

Biogas compared to other methane-containing gases: natural gas is the mostwell-known methane-containing gas that is divided into two groups H-gas and L-gas.The table 12 shows a comparison of specifications of natural gases with biogases(agricultural biogas, biogas from sewage plants, landfill gas)

Table 12: Biogas composition compared with natural gas

20

Source: [Dieter D, Angelika S, 2008]

When comparing biogas with the natural gas, biogas contains methane less thannatural gas but it is still flammable The following table presents the general energycharacteristic of biogas

Table 13: General energy characteristics of biogas

Source: [Dieter D, Angelika S, 2008]

21

2.3 Substrates for anaerobic digestion

Generally, all types of biogas can be substrates for the anaerobic digestion as long

as they contain carbohydrates, proteins, fats, cellulose and hemicelluloses as maincomponents, such as liquid manure, domestic waste, sewage sludge…

The practical methane yield that is attained from the anaerobic digestion depends

on many factors such as composition, grain size, and proportions of the assignedsubstrates, on microbial degradability of biomass, the content of dry matter and organicdry matter and the relationship of the nutrients to each other And it also depends oncharacteristics of the technology used, such as the number of stages, the temperature,the residence time of the substrate, and the quantity and frequency of the substrateaddition These parameter should be analyzed and measured before constructinganaerobic plants

III BIOGAS PROJECT IN VIETNAM

3.1 Project overview

The support project to biogas program for the animal husbandry sector in Vietnam

is implemented by Livestock Production Department (under MARD), in cooperationwith Netherlands Development Organization – SNV, that has been started since 2003and done until now

The long term objectives: Improve the livelihood and quality of life of rural farmers

in Vietnam

The short term objectives:

- Prevent and reduce the environment pollution caused by livestock manure; Contribute to minimize the green house emission;

- Provide bio slurry for cultivation and livestock production to produce clean products;

- Additionally support to establish socioeconomic organizations and enterprisesdoing the biogas services; contribute to improve the livelihoods and quality oflife of the rural farmers in Vietnam

http://210.245.92.22/english/Home.aspx

3.2 Technology of anaerobic digester used in the project

3.2.1 Structure of the anaerobic digester

The biogas technology used in the project is designed and developed byVietnamese engineers to make it suitable with the environment conditions in Vietnam,named the “fixed dome biogas plant” That is the digester with simple structure and

continuous feeding mechanism, including six main parts [MARD, SNV, 2007]:

(1) Mixed tank: is a place to discharge feedstock

(2) Inlet pipe: lead input materials to digester

(3) Digester: the main part of biogas plant Slurry is contained andfermented in the digester for biogas production

(4) Outlet pipe: similar in the structure with the inlet pipe However insidediameter of outlet can be smaller than or as big as the inlet pipe

(5) Compensation tank is a dome shape and with a function to regulate gaspressure in digester Additional this tank also contains bio-slurry and act as avalve to protect digester

(6) Gas pipe: is connected to the gasholder of the digester to collect andtransport gas out of the digester

[MARD, SNV, 2007]

Advantages of these types:

- Saving construction materials because the surface area is small and bricks are laid slantingly which result in best strength

- Use common materials and minimize using of steel

- Area of sphere gas storage is small, without corners to reduce gas loss and avoid cracks

- Digester’s surface is underground and thus it can save space, limit the

influence of low temperature outside and keep temperature stable

- The slurry surface is always up and down, reduce the formation of scum

- Use common struction materials which are available in province and local mason can do the construction work

- Digester dimensions can be changed as long as suitable with climate, quantity