LITERATURE REVIEW
Greenhouse gas emission issues
1.1.1 Greenhouse effect and Greenhouse gases
Greenhouse gases (GHGs) are gaseous component of the atmosphere
However, clouds and they absorb and emit radiation at specific wavelengths within the spectrum of thermal infrared radiation emitted by the Earth’s surface This property causes the greenhouse effect Methane (CH4), carbon dioxide (CO2), nitrous oxide (N2O), zone (O3) and water vapor (H2O) are the main GHGs in the Earth’s atmosphere (Tab.1.1) [3] According to Montreal Protocol, the chlorine and bromine containing substances and the halocarbons are included Besides CH4, N2O and CO2, sulphur hexafluoride (SF6), hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs) are dealt with in the Kyoto Protocol [3]
Table 1.1: Main sources of GHG emission [4]
CH4 emission N2O emission CO2 emission
Methane (CH4) emission is from the transport of coal, natural gas, and oil and produce activities
Decomposition of organic wastes in municipal solid waste (MSW), in agriculture, landfills also generate it Estimating methane emissions from livestock relate to animal species, feeding, performance and gross energy
The calculations are based on conversion factors for each field
Nitrous oxide (N2O) is emitted from industrial and agricultural activities, even comes a part of combustion of fossil fuels or solid waste
Carbon dioxide (CO2) is emitted to atmosphere via burning such as fossil fuels (e.g oil, coal and natural gas), wood, solid waste or made from chemical reactions Carbon dioxide could get rid of the atmosphere by plants or participate in carbon cycle
Greenhouse effect is known as phenomenon in which GHGs absorb thermal infrared radiation and then emitted again to the Earth’s surface as well as the atmosphere Because of emission all sides, GHGs create a trap heat at surface- in the troposphere, thermal infrared radiation relate directly to temperature of the atmosphere depending on the altitude where it is emitted Normally, the temperature in the troposphere decreases with height However, due to increase concentration of GHGs leading to heat kept in layers near the surface of the Earth [3]
Figure 1.1: Greenhouse effect (US-EPA)
Environmental impact of Greenhouse effect is one of issues discussed in many workshop and conferences There are several core impacts which could be mentioned Firstly, it is very important is global warming Because it will affect to a large area and specially, it leads to temperature increase Therefore, this issue will be global issue and become the reason of climate change The sea level rise would be the second effect and finally, impact on human life (e.g agricultural impact; economic impact, eco-system, hydrological cycle…) [4]
In fact that Vietnam is one of the countries is vulnerable by climate change
According to a research about Global Climate Risk Index (CRI), Vietnam was at No.05 th (in 2016) and No.06 th (in 2017) in ranking countries which were effected by climate change (Annex A.1; A.2) So that in near future many coastal areas of Vietnam will be stayed under the sea level The Red river delta and the Mekong river delta are typical areas for adapting to climate change in Vietnam [5]
The annual reports of IPCC is very important, several reports from them are
“synthesis reports” (AR1-1990, AR2-1995, AR3-2001, AR4-2007, AR5-2014) and it will be expected new “synthesis report” AR6 in 2022 The Fig.1.2 was taken from
“Synthesis report 2007: climate change”, it was shown that GHGs emission increased more than 70% in 34 years [3] Total emission in 2004 is 49 Gt CO2eq/year (Fig.1.2)
However, share of different GHGs in total emission relatively were stability in many year and agriculture was about 13.5% of total emission (Detail of Annex A.3) a) Global anthropogenic GHG emissions, annual (1970-2004) b) Contribution of anthropogenic GHG in total emission (2004) c) Contribution of different sectors in total emission (2004)
Figure 1.2: Global anthropogenic GHG emissions [3]
According to the AR4-report (Fig.1.3), total emission in 2010 reach again to value of 2004 (49 Gt CO2eq/year) By acting together, GHGs emission was controlled stably from 2004 to 2010 Nevertheless, AFOLU sector is 24% and approximately 1% from indirect CO2 emission (the map of contribution in Annex A.4) From data of FAO, it could recognize that agriculture emission of the world raises near the 2 times from 1961 to now (Fig.1.4) Manure management also contributes approximately 40 percent into total emission Moreover, emission of Asia is the largest (39.5%); Americas as well as Europe is smaller respectively 25.5% and 18.3%
Figure 1.3: Greenhouse gas emissions by sectors [6]
Figure 1.4: Agricultural emission total and manure management of the world
If each country do not act, an expected trends in GHGs emissions in 2030 (Fig.1.5), global emissions will increase to 62 Gt CO2eq (including CO2 emissions of land use) Therefore, countries is developing such as China (5.5 Gt CO2eq), India (2.7
Gt CO2eq) will be affected On the other hand, emissions in the most developed countries are expected to remain more or less constant in period 2010 – 2030 [7] A part of raw data are shown in Annex A.6
Figure 1.5: A forecasting global GHGs to 2030 (Source: PBL FAIR/IMAGE/TIMER model calculations and OECD 2012) [7]
It could realize that the big countries with the large area as well as population usually contribute plenty of GHGs emission in the agricultural sector They need
Emissions (CO 2 equivalent), Agriculture total of the world, unit: kt (CO 2eq ) x 10000
Agriculture total of the world
Manure management of the world maintaining the large scale of agriculture in order to protect food security themselves
Therefore, it can explain why the emission of China and United States are higher many times than in other countries (Tab.1.2).
Table 1.2: Top 10 emitters (CO 2 equivalent) average 1961 - 2016, Agriculture total (FAO)
C h in a, m ain lan d USSR ( * ) Un ited States o f Am er ica In d ia R u ss ian Ger m an y Fra n ce B raz il Sp ain C an ad a
(*)USSR: Union of Soviet Socialist Repubics
According to FAO’s inventory data, the contribution of each agricultural sector depends on geographical location, culture, natural condition… Asia countries are rice cultivation so it is often bigger while generally on the world, emission from enteric fermentation is the biggest contribution
Figure 1.6: Agricultural emissions by sector
Generally, emission from manure management of the World, Japan as well as Vietnam is also roundly 7-9% in total agricultural emission In addition, share of sectors are not too different between Vietnam and Japan (Fig.1.6).
Figure 1.7: Share of sectors in manure management
As mentioned above, although emission of manure management sector is about 9% (Fig.1.6); it increases fast more than two times from 1961 to now Manure management sector includes some sub-sectors In case of Vietnam, among sub- sectors emission of swine (market, breeding) is very important contributing roundly 60% total (Fig.1.7) A half of agricultural emission comes from methane emission
All of emission inventory data are shown somewhat the necessary of methane (CH4) emission from manure management, especially for piggery
1.1.3 Greenhouse gases emission data and estimation
The database is quite important in researches This thesis is used two types of data Firstly, international emission data were collected from three famous organizations (e.g FAO; OECD, World Bank) Raw data is published and not difficult to download and use but it needs selecting and analyzing carefully.Secondly, local emission data were estimated from specific information of that place Method for estimating is referred guidelines of IPCC, UNFCCC, and Japan Almost used data is agricultural emission or relationship to agricultural activities To understand the idea for calculating methane emission Fig.1.8 and Fig.1.9 would describe a part of them Although there exist three approaches, almost they based on the method of IPCC as a primary reference They were built up and modified for specific conditions and each country Therefore, several name or value of emission factor could be same somewhat
Figure 1.8: Approaches way in estimating GHGs emission
According to IPCC, agricultural activities are included in AFOLU group (Agriculture, Forestry and Other Land Use) The Fig.1.9 could illustrate about it The estimates of GHGs emissions deriving from AFOLU sector includes [8] :
• “CO 2 emissions and removals resulting from C stock changes in biomass, dead organic matter (DOM), soil organic matter (SOM) of organic and mineral soils, and harvested woody products (HWP) for all managed lands;
• CO 2 from cultivated organic soils;
• Non-CO 2 emissions from fire on all managed land;
• CH 4 emissions from rice cultivation;
• N 2 O emissions from all managed soils;
• CO 2 emissions associated with liming and urea application to managed soils;
• CH 4 emissions from livestock enteric fermentation;
• CH 4 and N 2 O emissions from manure management systems”
There are many sub - category in agricultural emissions, but in this thesis focuses on sub-category: “CH 4 emissions from manure management systems”
Figure 1.9: GHGs emission sources in AFOLU sector [9]
The issues in waste management of Vietnam
1.2.1 Pig manure, agricultural by product and domestic waste
Nowadays, there exists many issues in rural area of Vietnam, especially as GHGs emission Locally agricultural residues are disposed following each season and manure are from farms such as swine, chicken…; even solid waste from daily life
Therefore, solid waste treatment become so urgently in rural area National environment reports of Vietnam were pointed out thatNational environment reports of Vietnam were pointed out more than 76 million tons of straw estimated and about
47 million tons of livestock waste are generated each year in rural areas (excluding a large amount of production waste from craft villages) In addition, agricultural solid waste, it is also necessary to pay attention to a large number of pesticide fertilizer packages and must not be collected and disposed of properly Along with the increase in the number and quantity of animals, environmental pollution caused by livestock waste is increasing Each year, livestock waste is discharged into the environment to over 80 million tons of livestock solid waste (Tab.1.3) including manure, garbage, food waste, animal and poultry carcasses According to statistics so far, about 40-50% of waste is treated, the rest is discharged directly into ponds, lakes, canals and creeks [2]
Table 1.3: Solid waste in livestock of Vietnam [2]
Species kg- waste/head/day
Year (Unit: 10milion tone/year)
According to statistics of MONRE and World Bank, the volume of swine manure is around 20 million tons per year This value seems stable several recent years (Fig.1.10)
Figure 1.10: Volume of manure in livestock of Vietnam 2010-2014 [10]
Since there are many advantages in natural conditions, livestock of Red river delta is quite developing especially as swine and poultry With the abundance of agricultural products, they are big feed sources for livestock However, the RRD is also limited area in area, so that the load of waste per one kilometer square is greater several times than other regions In this, waste of pig contributes up to 300 t/km 2 in
RRD: Red river delta, NMM: Mountainous and Midland, NSCC: North and South Central Coast,
CH: central highland, SE: South East, MRD: Mekong river delta
Figure 1.11: Animal waste discharged by economic region of Vietnam 2014 [10]
Almost the population and economic activities of northern rural centralize in Red river delta Hence, this area creates a big market for consuming pork GHGs emission usually is greater than in other economic regions (Tab.1.4)
Table 1.4: GHG emission in livestock by economic region sectors,
RRD: Red river delta, NMM: Mountainous and Midland, NSCC: North and South Central Coast,
CH: central highland, SE: South East, MRD: Mekong river delta
According to Vietnam’s National State of Environment 2010, amount of solid waste generated of rural areas in 2003 was 6,400 kt/year and in 2008 was more 9,000 kt/year A forecasting at that time, the load could increase to approximately 10,000 kt/year Each person in rural area was discharged 0.3 kg/day (2003) and 0.4 kg/day
Figure 1.12: The contribution of domestic waste in Vietnam' rural (2007) [12]
In Vietnam, following MONRE it could be divided into 3 categories for rural solid waste: 1- Craft’s solid waste (various types and sources); 2- Agricultural solid waste (cultivation, fertilizer, harvesting, animal husbandry,…); 3-Rural domestic solid waste (family households, hospitals, market, ) [12] The main part of agricultural solid waste is the agricultural by-products such as rice husk, rice straw, and other
The volume of them increases fast during harvest times The kinds of agricultural residues depend on regions and seasons The delta is suitable for growing vegetables, rice while in a highland area coffee tree is a typical tree [13]
The Mekong river delta and Red river delta are areas contributing a large of rural domestic waste The domestic waste of Red river delta shared 23% in total domestic waste of Vietnam (Fig.1.12) Agricultural solid waste contains various contents and majority of them are biodegradable (e.g rice straw, husk, stubble, livestock manure, animal husbandry waste Besides, it could be hazardous waste, persistent or pesticide
In fact that livestock wastes could lead to pollution (air, soil, and water) There are amount of waste treated, but a large of them discharged in to environment Open dumping and composting are typical solutions in rural area of Vietnam as well as in ASEAN (except for Singapore); open dumping is 50-80% and composting is about 5-15% (Fig.1.13)
Figure 1.13: Waste treatment in ASEAN [14]
Agricultural by-product somewhat could be used to compost or feed for animals
Rice straw also are bought to material for grow mushroom while a large of vegetable residues are dumped into fields to decay by the time In farms, they apply biogas digestions for treating or using it as fertilizers As you know co-digestion is new approach and it could solve both issues Manure and agricultural by-product or household waste are mixed following a ratios after putting into an anaerobic co- digestion tank They are decomposed together; so generally it might decrease the volume of reactor GHGs emission is different between traditional biogas and co- digestion At small-holder farms, rice straw and pig manure could be composted together and then they are used as fertilizer [10] Many farms apply biogas digesters to deal with manure However, there are 65 percent of farm in Hanoi applying non- biogas Normally, they divide into liquid fraction for making fertilize and dry-matter- rich for composting in the field or in their garden The time for composting could be from 3 to 4 months and in liquid fraction, clear water and urine are stored All of them also are used for the crop as fertilizers [15]
According to a report of World Bank, there are 30 percent of pig farms in Vietnam separating collection of liquid (urine,…) and solid waste (feces, ) However there are about 60 percent of farms treat a mixture of them [10] In Japan, separating the urine and feces is very necessary If they cannot separate in advance, they will collect together and then dehydrate in order to divide into 2 parts (liquid and solid phase) (Fig.1.14) a) Yagi bioecology center b) Kikugawa research center
Figure 1.14: Dehydrate system of livestock treatment in visited center in Japan
Almost farmers use biogas from anaerobic digesters for cooking and lighting It is too enough to use, so that they supply for their neighbors; even emit directly to environment However, it is not problem, cookers and equipment are rusted as well as damaged after using 2-4 years Therefore, they have abandoned using biogas when projects or programs are finished Dihydrogen sulphide (H2S) is the reason of this issue, it should have removed before cooking [15]
In general, in recent years, there have been a number of studies and a number of animal waste treatment models implemented in Vietnam (Tab.1.5) Although the success of each model is different, it contributes to reducing pollution Although the current methods of treating livestock waste are based on technologies that have been successfully applied in the world, to meet the Vietnamese reality, there are still many difficulties due to diversified animal husbandry, investment capital and low operating costs, qualifications of farmers and knowledge have not met the demand
Table 1.5: Summary of studies regard to co-digestion
No Content of research Author Year
Optimization of the specific methanogenic activity during the anaerobic co-digestion of pig manure and rice straw, using industrial clay residues as inorganic additive
2 Determining C/N ratios for typical organic wastes using biodegradable fractions
3 Effects of mixed difference combination between Zea mays and Pistia stratiotes L N.L.Phuong et al 2015
4 Estimation of methane and nitrous oxide emission from livestock and poultry in China during 1949–2003 J.B Zhou et al 2007
Anaerobic co-digestion of animal manures and lignocellulosic residues as a potent approach for sustainable biogas production
Mesophilic anaerobic digestion of pig slurry and fruit and vegetable waste: Dissection of the microbial community structure
Semi-continuous anaerobic co-digestion of sugar beet byproduct and pig manure: Effect of the organic loading rate
8 Feasibility of anaerobic co-digestion of pig waste and paper sludge
A research on the ability to treat pollutants in livestock waste by biogas system shows that the concentration of pollutants in livestock waste is significantly reduced after passing the biogas system, especially BOD5 and COD in waste water
METHODOLOGY
Concept of estimating emission reduction
In this thesis, GHGs emission was estimated in two scales The first are small scales which are farms and the second are large scales which are countries
Calculating emission in small scales based on guidelines and tool of three approaches of UNFCCC, IPCC as well as Japan Baseline emission (BE) were calculated when they do not any activities for treatment or managing waste; then if there are project activities of emission reduction (ER), the emission of those activities will be calculated following guidelines of each approach The reduction activities in this thesis focus on improving the realistic system (reduce water consumption, utilize biogas) and increase the efficiency of reaction by trying co-digestion pilot with three types substrates (manure, agricultural residues and domestic waste)
The estimated value of farms are scale up for whole of commune with similar condition assumption Comparison between Baseline emission (BE) and project emission (PE) of reduction activities show somewhat GHGs emission reduction (ER)
Besides, conducting and analyzing emission data from several famous international organizations for large scales By simply way, it is illustrated by this equation 2.1:
There are many sources of emission data However, data were conducted from World Bank, OECD, FAO as well as IPCC reports, which are reliable Draw data were downloaded, then they were re-calculated The links in below are used to export data about GHGs emission In this sector, GHGs emission of Vietnam and the World are analyzed by those data https://data.World Bank.org/indicator/EN.ATM.CO2E.KT https://stats.oecd.org/Index.aspx?DataSetCode=AIR_GHG http://www.fao.org/faostat/en/#data/GT
The data in these links are free, so it is not difficult to collect them However, there are plenty of data of fields; in this case, agricultural emission data are preferred
All parameters were measured and analyzed at Laboratory of Assoc Prof DO QUANG TRUNG in VNU University of Science (HUS) with my project team The sections in below will perform them detail.
Approaches of estimating GHGs emission
Generally, there exists many tool as well as method in order to estimate GHGs emission in the world The method of IPCC was enforced at 1996 and updated on newest version at 2006 [9] IPCC Guidelines were first accepted in 1994 and published in 1995 UNFCCC COP3 held in 1997 in Kyoto reaffirmed that the Revised 1996 IPCC Guidelines for National Greenhouse Gas Inventories should be used as
"methodologies for estimating anthropogenic emissions by sources and removals by sinks of greenhouse gases" in calculation of legally-binding targets during the first commitment period This is basic guideline which my countries applied or used it to develop a new method for themselves Several CDM (Clean Development Mechanism) and tool of UNFCCC were also applied for calculating Moreover, Japanese method was referred and compared with Vietnam Detail of methodology in below:
IPCC: 2006 IPCC Guidelines for National Greenhouse Gas Inventories, emissions from livestock and manure management (Volume 4: AFOLU, Chapter 10) [17] ; Biological treatment of solid waste (Volume 5: Waste, Chapter 4) [18] , Solid waste disposal (Volume 5: Waste, chapter 3) [19]
UNFCCC: AMS.IIID (Methane recovery in animal manure management systems) [20] , AMS.IIIH (Methane recovery in wastewater treatment) [21] , AMS.IC (Thermal energy production with or without electricity) [22] and Tool 04 in Methodological tool of CMD [23]
National Greenhouse Gas Inventory Report of Japan 2018 [24]
The classifications of IPCC is basic for other approaches in order to build up specific formulas Greenhouse gas emission and removal estimations are divided into main sectors, which are groupings of related sources, processes and sinks:
Industrial Processes and Product Use (IPPU);
Agriculture, Forestry and Other Land Use (AFOLU);
According to the IPCC-2006 Guidelines report, three tiered approaches related to methods which are used in the AFOLU Sector:
Tier 3: the most demanding, complexity and data requirements
Regarding to application for estimating CH4 emission of swine, emission factor is chosen in Chapter 10 IPCC-2006 and is referred from UNFCCC, Japan as well as previous researches in Vietnam [17]
There are many researches focusing on many animals in agricultural production and other sector such as CH4 emission from enteric fermentation, N2O emission from manure management [25] [26] However, this thesis analyzes CH4 emission from manure management and object is swine Moreover, the calculating is applied for many approaches of organizations and countries.
CH 4 emission in solid waste management
Methane emission from agricultural by-product as well as domestic waste disposal has relied on IPCC guideline Volume 5 (Chapter 3 for Solid waste disposal)
[19] Following this way, amount of methane emission is determined by equation 2.2; equation 2.3 and equation 2.4 in this document But it must assume that the amount of CH4 recovery (RT) is trivial and could omit them Moreover, the oxidation factor (OXT) is selected as 0, because solid waste disposal (SWDS) is usually in unmanaged and uncategorized SWDS In addition, DOC (degradable organic carbon) and DOCf
(fraction of DOC) depend on type of solid waste, for instance:
Table 2.1: DOC and DOC f of typical solid waste [18]
Equation 2.2 for CH4 emission from SWDS:
Equation 2.3 fordecomposable DOC (degradable organic matter) from solid waste disposal data:
(2.3) Equation 2.4 for CH4 generation potential:
Whole emission factors in above equations are shown that:
𝐶𝐻 4 CH4 emitted in year (Tone) Estimated value
𝐷𝐷𝑂𝐶 𝑚 Decomposable DOC (T/T-waste) Estimated value
DOC Degradable organic carbon Refer Table 2.1
DOC f Fraction of DOC Refer Table 2.1
W Mass of waste (T) Depend on
MCF Methane conversion factor (MCF) for the baseline animal manure management system j 1
F Fraction of CH4 generated in disposal site 0.5
Calculation GHGs emission in livestock management
In the scope of this thesis, livestock management is understood in narrow meaning that is manure from piggery Manure is defined as product from livestock including urine (liquid) and dung (solid)
First of all, we need to understand that what is baseline emission (BE)? The figure in below is briefly baseline emission concept [20]
Figure 2.1: Concept of Baseline emission [20]
According to AMS III.H of UNFCCC, baseline emission scenario has some conditions regarding to environmental temperature (>5oC), manure retention time (>1 month); in case of using anaerobic lagoons, the depth of them are at least 1 (m)
In addition, system is without methane recovery and do not use combustion and flaring for destructing methane generation (Fig.2.1)
Equation 2.5 is used for baseline emission Almost factors are chosen from default value or referring to suitable value which are attached:
𝐵𝐸 𝑦 Baseline emissions in year y (t CO2eq) Estimated value
𝐺𝑊𝑃 𝐶𝐻4 Global Warming Potential (GWP) of CH4 applicable to the crediting period (t CO2eq/t CH4) 25
𝑈𝐹 𝑏 Model correction factor to account for model uncertainties 1
𝑀𝐶𝐹 𝑗 Methane conversion factor (MCF) for the baseline animal manure management system j 0.7
Maximum methane producing potential of the volatile solid generated for animal type LT (m 3 CH4/kg-dry mass)
𝑁 𝐿𝑇,𝑦 Annual average number of animals in year (day) (refer Annex
𝑉𝑆 𝐿𝑇,𝑦 Volatile solids production/excretion per animal of livestock (kg/head/day) 0.3
𝑀𝑆% 𝐵𝑙,𝑗 Fraction of manure handled in baseline animal manure management system j 100 %
To estimate CH4 from livestock manure, IPCC recommend that: firstly, choice of method; secondly, choice of emission factors and finally, choice of activity data
The choice of method is very important It should base on data and national condition of each country in order to apply suitable method As mentioned, there are three methods (Tier 1, Tier 2, Tier 3) [17] Decision tree for choosing suitable methods was supplied by IPCC in Annex A.17
Tier 1: A simplified method that IPCC default emission factors are estimated emissions Therefore, this method will be reasonable for developing countries as Vietnam
Tier 2: A more complex This method needs more detailed information manure management practices as well as animal characteristics, so it could develop emission factors specific depending on the conditions of the country
Tier 3: It usually is applied by developing countries Through Tier 2 and create country-specific methodologies or apply measurement–based approaches in order to quantify emission factors
This thesis selects Tier 1 for estimation so that the steps and formulas will follow as Tab.2.2 However, if choosing Tier 2 or Tier 3, it is necessary to propose another procedure as well as formulas
Table 2.2: Steps of estimating CH 4 emission
FOR MANURE MANAGEMENT TIER 1 - BASELINE
B1 Find number of swine Survey
B2 Conduct the Day alive time Survey
B3 Choose Emission factors (temp.) Tab 10.14 IPCC chapter 10 for manure management B4 Estimate CH 4 following Eq 10.1 & 10.22 IPCC chapter10 for manure management
Equation 2.6 is based on the Equation 10.22 in IPCC chapter 10 for manure management [17] :
𝐶𝐻 4,𝑀𝑎𝑛𝑢𝑟𝑒 Methane emission from manure management kt CH4/year
Emission factor is chosen from table 10.14 inIPCC chapter 10 for manure management at 25 o C of average temperature (kg CH4/Head/year)
N Annual average population (refer Annex
According to the National Greenhouse Gas Inventory Report of Japan 2018, it is concerning to agricultural emission the methods and emission factors (EF) are shown in the table below It could see that emission is calculated by Tier 1 (T1) and default (D) emission factors [24]
Table 2.3: Japanese estimation methodology in agricultural sector [24]
2.4.2 Project activities in emission reduction
Nowadays, waste treatment in piggery is very important for keeping environment and protecting human heath around It is popular way, biological treatment technologies were applied in many countries
According to IPCC volume 05-chapter 04 for biological treatment systems, estimating CH4 emission is calculated briefly by steps and equations The Tab 2.4 is a summary of the procedure for estimating emission of biological treatment
Table 2.4: Steps of CH 4 estimation in biological treatment
Estimation CH 4 emission from biological treatment of waste Tier 1 after treatment
B1 Find number of swine Survey (Growing 30-50), finishing
80-100, breeding B2 Find amount of waste treated Survey
B3 Choose emission factors following biological type Tab 4.1 IPCC for biological treatment -
IPCC for biological treatment -Waste chapter
Equation 2.7 for estimating CH4 emission is the equation 4.1 in IPCC guideline [18] :
CH 4,Emission Methane emission from biological system
EF Emission factor is chosen from table 4.1 of IPCC guideline vol.5 (g CH4/kg waste treated)
M Mass organic of treated waste from biological system (kt) Measure
Figure 2.2: Project activities for GHGs emission reduction [20]
Anaerobic treatment is a popular project emission for managing livestock (feces and urine) as well as reducing methane emission However, estimating the baseline emission of each treatment system should consider the emission of wastewater after treating (Fig.2.4) In Vietnam, flow wastewater of farms relatively is high while COD removal efficiency is low Therefore, the CH4 emission from the discharge of wastewater should have included in calculations
According to AMS.IIIH and AMS.IID, it could determine the CH4 emission of anaerobic digestion The equation 2.8 is determined:
The methane emissions from wastewater discharged to water body such as lake, creek, river or sea It is estimated by this equation 2.9 below:
𝐶𝑂𝐷 𝑖𝑛 Chemical oxygen demand COD inflow to baseline treatment in year (t/m 3 ) Measure
𝐶𝑂𝐷 𝑑𝑖𝑠𝑐ℎ𝑎𝑟𝑔𝑒 Chemical oxygen demand COD inflow to baseline treatment in year (t/m 3 ) Measure
𝜑 COD removal efficiency Refer Annex
𝑀𝐶𝐹 1 Methane Correction Factor (Anaerobic without CH4 recovery) 0.80
𝑀𝐶𝐹 3 Methane Correction Factor (direct to lake and creek) 0.1
𝐵 0,𝐿𝑇 Maximum CH4 producing capacity kg CH4/kg COD 0.25
As mentioned above, estimating the baseline emission of Japan is based on IPCC guideline Nevertheless, there is a new method built for estimating emission from biological treatment systems In this case, countries-specific (CS) could be specific emission factor as well as new formulas It is calculated via CH4 emission per mass of organic matter Feces and urine are two main content of organic matter (OM) and CH4 emission is determined from the value of OM Depending on animal categories and technical treatment, CH4 emission values are different (Annex B3-B6)
2.4.3 Emission reduction applies in case of Vietnam
To reduce GHGs emission need co-operation from many stakeholders Polices emission are important in research long-term strategies [27] Besides, technical solution is also a part of emission reduction programs The idea are increase reaction efficiency as well as decrease GHGs reduction by changing behavior and reducing water consumption as well as creating removal CO2 and H2S system in order to utilize biogas for cooking and daily life
With input of biogas is high nitrogen content of animal manures, it could be effect to optimize C/N ratio required in system regarding to anaerobic digestion [28] Since, it need add the compound which rich carbon content before anaerobic digestion Agricultural residues content lignocellulosic which could supply for anaerobic digestion as substrates Co-digestion of lignocellulosic materials and animal manures ideas for a solution to balance the C:N ratio of feedstock for anaerobic digestion [29]
Co-digestion pilot model in rural area of northern Vietnam
Vietnam is in list countries which are affected by climate change According to a research report of Climate Central about sea level rise, more 23 million Vietnamese people will be threatened It means that approximately 26% of the national population affected We just were behind Holland in vulnerable level Moreover, as mentioned solid waste management is one of the issues existing during this time Agricultural by-product and domestic waste in countryside are not collected reasonably The abundance of these materials are sources which could add carbohydrate for traditional biogas Therefore, an idea about co-digestion known as new approach instead In addition, solutions of improving realistic system such as reduce water consumption, treatment biogas to utilize it for daily life
This is the experimental model 01: at Lam Dien commune, Ha Noi’s countryside
One piggery farm was chosen to test management model for livestock Many farms were built so explosively that overload the environment
Waste water includes manure and washing water collected into biogas tank
Before flowing into biogas tank, there is a small tank for monitoring and sampling
Volume of anaerobic tank is 900m 3 and gas bag HDPE is 600m 3 Capacity of Mr.Toi’s farm is around 1200 head, but there are twice a year exportation and retiring time is about 1 month between each batch
This is experimental model 02: at Hai Dong commune, Nam Dinh province It is coastal area where were applied composting program for garbage from daily life activities of local people instead of landfilling There is a different from pilot in Lam Dien, the pilot model of Hai Dong could control temperature because it was integrated a heater and isolator system This capacity is only 300-500 head and it has also twice a year exportation
In fact that water consumption for washing pig lodging is large and redundant
Therefore, traditional biogas could be overloaded, even it is not effective due to diluting wastewater input Lam Dien and Hai Dong commune [29]
Co-digestion is known as solution which could use two substrates input Instead of treating only manure from livestock farms as traditional biogas, co-digestion might treat the second input such as agricultural residues, domestic waste,
The main parts of anaerobic co-digestion system includes one anaerobic tank and biogas treatment by series Besides, there is a pump for mixing; a gas bag for sampling and other auxiliary parts such as valves, thermometers, pressure gauges and electric cabinet The biogas treatment system has a role as H2S removal, CO2 storage as well as enrich the concentration of CH4
One column activated carbon and iron shavings
For instance, washing time of Mr.Toi's farm usually lasts 75-85 min/turn, twice a day, water consumption is about 23-25 m 3 So that his farm consumes 46-50 m 3 daily, average for each pig is 42-44.5 L/d It is relatively higher than popular 10-
40 L/d Like as a half of Mr.Toi's farm capacity, the water consumption of Mr.Manh's farm is around 25 m 3 /d for 500 head pig, the water consumption is reduced about 15% Organic matter may be diluted by high water content in discharged waste, since it could lead process inhibition [29]
It is performed with the aim of reducing the size of materials and enhancement of heat and mass transfers so that consequent digestion process can be facilitated
Milling is a common method of mechanical pretreatment which provides smaller particles Pre-treatment includes 03 main steps (Fig.2.3):
Figure 2.3: The steps of raw material pre-treatment for co-digestion system
Step 1: Collection agricultural by product;
After collecting agricultural residues, they are cut and milled (1-3mm) in order to homogenize Then, they were mixed with livestock and put into reactor However, a research showed that enhance the solubility of organic matters was affected by pretreatment, but it was a required pretreatment to reduce the biomass size to below
Operation mode of co-digestion pilot (Fig.2.5):
Table 2.5: Co-digestion system mode
Mode HRT Volume tank Temp Raw material
Batch 25 day 1 m 3 Natural condition Manure a) Agricultural residues b) Domestic waste
The input of co-digestion is mixed substrate 1 with a type of substrate 2 at different mass ratio:
- TN2: Swine livestock + Agricultural residues or Domestic waste 10%
- TN3: Swine livestock + Agricultural residues or Domestic waste 15%
RESULTS AND DISCUSSIONS
GHGs emission from livestock management of Vietnam
From raw data of World Bank and FAO about Vietnam, it could calculate share of total agricultural emission in total GHG emission and agricultural methane emission among whole agricultural emission (Fig.3.1)
Figure 3.1: Contribution of total agricultural emission in total GHG emission of Vietnam
Figure 3.2: Contribution of GHG emission of agriculture in Vietnam
In this graph (Fig.3.1), it shows the contribution of total agricultural emission in total GHG emission of Vietnam The blue is sum of other components and orange is total agricultural emission Agricultural activities contribute more 60% CH4 of emission in Vietnam from 1970 to 1994 But it trends decrease following time and now it only about 40% (Fig.3.2)
Agricultural activities contribute quite large in total emission of the world (AFOLU: 24%); it was mentioned in previous chapter (Fig.1.3) By exploiting and using emissions data from FAO, OECD, as well as World Bank, it could take an overview regarding international emission
More than half total agricultural emissions of Vietnam is methane emission and loading of methane emission increase by years This is a general trend in the world; however, Japan showed a reverse trend
It is too difference between Vietnam and Japan during more 50 years, but development of agricultural emission follows two contrast ways While total emission as well as emission from Japanese management have mitigated, the developments of
Co n tr ib u tio n o f to tal agr icu ltu r al em issio n
Agricultural methane emissions (% of total) Agricultural other emissions (%)
Vietnam is shown that these emission increase fast (Fig.3.3) Trend of Vietnam is similar with general trend of the world Oppositely, Japan agricultural emission did not increase; even it was reduced in many years It could recognize that manure management systems as well as environmental policies of Japan were relatively effective in this phase (1960-2020) They have reduced agricultural emission for 50 years, especially as methane Through this, it might be lesson about environmental management
Figure 3.3: Agricultural emission total between Vietnam and Japan
Figure 3.4: Estimating evolutions of Methane (CH 4 ) emission and swine
Emissions (CO 2 equivalent), Agriculture total of
Vietnam agriculture total Japan agriculture totalVietnam manure management Japan manure management
At 2008 the emission of methane increases spike and population of swine, too
A number of swine population are high suddenly at that time (Fig.3.4) The reason why could be area of Ha Noi city expending, it was merged Ha Tay province to Ha Noi city in 2008 Therefore, data of Ha Noi city was inventoried with data of Ha Tay province together.
GHGs emission reduction from livestock management of Japan
Suzuyo Shoji has put into motion “Biogas power generation method”, which conducts electricity from the waste The ingredients used the dispersed waste of tomatoes, coffee granules, oil, soil extracts, and mown grass with agricultural residual substances
It assumes that on the waste treated: 2% N in dry matter, 20-50% DOC in dry matter and moisture content 60% (Annex B.7 for food waste) [18] The CH4, which is generated after anaerobic digestion is burned in order to make stream It keeps heat for reactor and also generates electricity
According to data of this factory, the input material is mix gas between 5,726 mol/day of CO2 and 33,219 mol/day of CH4 However, the efficiency of burning does not complete (95%), so that it emits 0.53 Gg/year of CO2 (converted from 95% of CH4 input), 0.37 Gg/year of CO2 (non-burning) and 0.01 Gg/year of CH4 (5% no- reaction) It is convenience to estimate emission All of them were converted to global warming potential (GWP) with kt CO2eq/year of unit, the Tab.3.2 shows those converted values
A large amount of CH4 was converted to CO2 (efficiency 95%) Because the effect of CH4 is 25 times as great as CO2, which based on convert coefficient between
CH4 and CO2 (Annex B.8) Therefore, it would avoid relatively GHGs emission from
CH4 (reduce from 5.11 to 0.26 kt CO2eq/year) With 855 Nm 3 /day of CH4 gas productivity, they could supply for electric (2,500 kWh/d) and heat (5,000 MJ/d)
Table 3.1: The results are calculated and analyzed from Kikugawa biogas power plant survey
Emission after anaerobic digestion Emission after biogas engine
CH 4 emission per 1 kg raw material (g CH 4 /kg raw material)
Besides, CO2 after refinery always available for "Bell farm" which is near this factory The CH4 emission per one kilogram raw material is 4.2 g/kg raw material (Tab.3.2) It is in range of the IPCC recommendation for anaerobic digestion
According to the collected data and National greenhouse gas inventory report of Japan 2018, some results are shown in table below (Tab.3.3)
Table 3.2: Initial estimation the livestock excretion and CH 4 emission
Emission GWP head kg/day kg/day kg/day kg CH4/year ton
The livestock excretion includes both feces and urine The volume of swine urine is about 15 L/day Due to special excretion, amount of chicken urine is too small
Therefore, in some document or guideline, it is skipped [24] They are mixed together and dehydrate in order to compost
Table 3.3: Calculation CH 4 emission following IPCC volume 5 for biological solid waste treatment.
Emission GWP head kg/day kg/day kg CH 4 /day kg
Because of data limitation, “Tier 1” was applied for estimating CH4 emission
The emissions from composting, and anaerobic digestion in biogas facilities, will depend on factors such as type of waste composted, amount and type of supporting material (such as wood chips and peat) used, temperature, moisture content and aeration during the process (Tab.3.4) CH4 emission per 1 kg raw material is 0.061 (g
CH4/kg raw material) After composting process, the CH4 emission compares with initial estimation Moreover, it is also in range which IPCC recommendation for composting process.
Estimation GHGs emission reduction from manure management at pilots in
The ratio of each The COD removal efficiency has changed following the development of input TN1 is a sample in traditional biogas while TN2 & TN3 are samples in co-digestion and TN4 is water reduction (Detail of parameter in Annex A.9 & A.10) The removal efficiency of co-digestion is better than traditional biogas because it takes C:N ratio to the suitable condition.The ratio of each sample C:N in each batch respectively: TN1: 21.6:1; TN2: 48.2:1 – 58.4:1; TN3 ~ 70:1
Baseline emission (BE) of swine farm
Depending on three approaches in estimating GHGs emission, it could apply for calculate emission by those ways Generally, there exist the differences among three approaches for estimating
Figure 3.5: Emission from traditional biogas of Mr.Toi's farm and Mr Manh’s farm
From results of Mr.Toi’s farm, if it assumes that treatment efficiency of other piggery farms is relatively similar with his farm, Lam Dien emission in swine manure management is estimated as table in below (Tab.3.4)
Table 3.4: Estimation of Lam Dien and Hai Dong emission reduction
BE Traditional biogas ER Efficiency ton CO 2 eq/year ton CO 2 eq/year ton CO 2 eq/year %
Hai Dong commune BE Traditional biogas ER Efficiency ton CO 2 eq/year ton CO 2 eq/year ton CO 2 eq/year %
There exists the different value among calculation methods (Fig.3.5) Normally, UNFCCC’s approach is greater than IPCC as well as Japan approach A reason of this differences could be emission factors (EF), sub-parameter and the detail of formulas The IPCC is a basic approach for all countries while the UNFCC’s approach takes more detail for each application The Japanese approach is the combination between the method of the IPCC and local customize in order to take specific emission factors
According to the guideline of each approach for anaerobic treatment, it could estimate baseline emission of Mr Toi's farm (in Lam Dien commune) as well as Mr
Manh's farm (in Hai Dong) The results are shown that both baseline emission and emission of biological treatment is relatively different Actually, the UNFCCC's approach gets value higher than the IPCC's approach and Japan's approach as well A reason to explain that it could be emission factors which were chosen to calculate in each approach Besides, there is an importance that UNFCCC's approach estimates for both emissions of anaerobic treatment and wastewater after treating, while the IPCC's approach and the Japanese approach does not include
Regarding baseline emission between the IPCC's approach and the Japanese approach, it is similar because the Japanese approach based on Tier 01 which is one default (D) of the IPCC guideline However, in estimating emission from biological treatment, they had a country-specific method and emission (CS)
From those results above, methane emission from the anaerobic treatment system of Japan is quite low, it is only 10 percent of their baseline emission In Japan, anaerobic treatment systems usually collect biogas and utilize them by generating electric in big factories or burning in small scales Moreover, they prefer treating centralization big scale in factories so management and operation could reach optimal conditions Therefore, methane emission of anaerobic system are controlled very well
Baseline emission (BE) from solid waste management
Almost agricultural by-products in Mr.Toi's farm are leaf, vegetables, created from daily product activities of his farm There are two types of pilot (Tab.3.5) The Mr.Mann's farm combines swine manure and domestic waste while the Mr.Toi's farm is swine manure and agricultural residues According to a survey, they are disposed to environment around 4-5 kg per day and methane generation potential could be up to 110 kg CH4 per year (2.7 ton CO2eq in Mr.Toi’s farm and 3.2 ton CO2eq in Mr.Manh’s farm) Commune scales are estimated with assumption that other farms in those areas are similar to Mr Manh’s farm as well as Mr Toi’s farm
Table 3.5: Emission of agricultural by-product and domestic waste
Global warming potential kg CH 4 /year ton CO 2 eq/year
Normally, Mr Manh’s family (~12 members) dispose of domestic waste more
6 kg/day Therefore, each person has about 0.5 kg-waste/day; it corresponds to national reports and previous research [31]
Mr Toi’s farm is the big farm combining swine, fish and growing vegetable so agricultural residues relatively are large But they depend on seasons and type of trees
This research was taken place in summer
Total baseline emission (BE): From estimated results above (Manure and Solid waste), total baseline emissions are calculated as table 3.6 below Total baseline emission in this case is the sum between swine manure emission and agricultural residue or domestic waste (depending on type pilot of each area).
Basic emission (BE) ton CO2eq/year
Total BE Manure Agricultural residue Domestic waste
Mitigating methane emission from manure management in this research includes traditional biogas, co-digestion, reducing water consumption and utilizing bio-gas This table below performs emission reduction potential Details of the calculation are enclosed in the annex A8-A16 Emission reduction of each project activities were estimated by equation 2.1
Emission reduction potential (ton CO 2 eq/year)
Total baseline emissions minus corresponding project emissions, which is emission reduction of each project activities such as traditional biogas and co- digestion The value of total BE was gained from Tab.3.6 above The approach of UNFCCC was chosen to estimate the emission of biogas system as well as co- digestion system Therefore, the equation 2.8 and 2.9 were applied for this case All parameters and coefficients are shown in Annex 12 & 13
It is concerning other project activities, reducing water consumption was calculated by the difference between before and after applying water saving (Annex 12&13) About utilizing biogas, emission reduction was estimated via amount of CH4 was consumed for daily life (e.g cooking, burning, )
According to this table above, if farm applies only biogas technology currently,
CH4 emission reduction potential is quite limiting (35-37%) Co-digestion could increase efficiency to 40-60% (depend on mixing ratio substrate) The TN3 (Mix15%) usually achieves high performance due to reasonable C:N ratio for anaerobic digestion Co-digestion system with adding substrate (10-15%) had potential methane generation relatively higher than in origin input The Fig.3.6 performs the potential of each emission reduction activities mentioned in this thesis
Reducing water consumption and utilizing biogas could help to decrease 4-10%, totally (Fig.3.6) Despite of the fact that convenient using biogas for daily life, almost farm in Vietnam do not utilize it They do not treat biogas before burning so it damages to cooker and causes material corrosion
In Vietnam, biogas systems are operated not good and do not customize for the specific condition as well as overloading so that efficiency is low and emission is high Co-digestion is a new approach; however, it needs to research more and optimize the process in order to increase efficiency
Figure 3.6: Emission reduction potential commune scale
The figure above shows that if it might apply this reduction idea for the whole commune, CH4 emission could reduce up to approximately 70% Before taking a comprehensive solution for solid waste management in the countryside area, those are simple approaches to cut down CH4 emission, currently
Biogas technology Co-digestion Reduce water consumption
Lam Dien communeHai Dong commune