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TYPE III - OTHER PROJECT ACTIVITIES 

Project participants shall apply the general guidelines to SSC CDM methodologies and information 

on additionality (attachment A to Appendix B) provided at 

<http://cdm.unfccc.int/methodologies/SSCmethodologies/approved.html> mutatis mutandis. 

III.H. Methane recovery in wastewater treatment 

Technology/measure 

1. This methodology comprises measures that recover biogas from biogenic organic matter in 

wastewater by means of one, or a combination, of the following options: 

(a) Substitution of aerobic wastewater or sludge treatment systems with anaerobic 

systems with biogas recovery and combustion; 

(b) Introduction of anaerobic sludge treatment system with biogas recovery and 

combustion to a wastewater treatment plant without sludge treatment; 

(c) Introduction of biogas recovery and combustion to a sludge treatment system; 

(d) Introduction of biogas recovery and combustion to an anaerobic wastewater 

treatment system such as anaerobic reactor, lagoon, septic tank or an on site 

industrial plant;1

(e) Introduction of anaerobic wastewater treatment with biogas recovery and 

combustion, with or without anaerobic sludge treatment, to an untreated 

wastewater stream; 

(f) Introduction of a sequential stage of wastewater treatment with biogas recovery 

and combustion, with or without sludge treatment, to an anaerobic wastewater 

treatment system without biogas recovery (e.g. introduction of treatment in an 

anaerobic reactor with biogas recovery as a sequential treatment step for the 

wastewater that is presently being treated in an anaerobic lagoon without methane 

recovery). 

2. In cases where baseline system is anaerobic lagoon the methodology is applicable if: 

(a) The lagoons are ponds with a depth greater than two meters, without aeration. The 

value for depth is obtained from engineering design documents, or through direct 

measurement, or by dividing the surface area by the total volume. If the lagoon 

filling level varies seasonally, the average of the highest and lowest levels may be 

taken; 

(b) Ambient temperature above 15°C, at least during part of the year, on a monthly 

average basis; 

 

1 Other technologies in Table 6.3 of Chapter 6: Wastewater Treatment and Discharge of 2006 IPCC 

Guidelines for National Greenhouse Gas Inventories are included. 
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(c) The minimum interval between two consecutive sludge removal events shall be 

30 days. 

3. The recovered biogas from the above measures may also be utilised for the following 

applications instead of combustion/flaring: 

(a) Thermal or mechanical,2

 electrical energy generation directly; 

(b) Thermal or mechanical, electrical energy generation after bottling of upgraded 

biogas, in this case additional guidance provided in Annex 1 shall be followed; or 

(c) Thermal or mechanical, electrical energy generation after upgrading and 

distribution, in this case additional guidance provided in Annex 1 shall be 

followed: 

(i) Upgrading and injection of biogas into a natural gas distribution grid with 

no significant transmission constraints; 

(ii) Upgrading and transportation of biogas via a dedicated piped network to a 

group of end users; or 

(iii) Upgrading and transportation of biogas (e.g. by trucks) to distribution 

points for end users. 

(d) Hydrogen production; 

(e) Use as fuel in transportation applications after upgrading. 

4. If the recovered biogas is used for project activities covered under paragraph 3 (a), that 

component of the project activity can use a corresponding methodology under Type I. 

5. For project activities covered under paragraph 3 (b), if bottles with upgraded biogas are 

sold outside the project boundary, the end-use of the biogas shall be ensured via a contract between 

the bottled biogas vendor and the end-user. No emission reductions may be claimed from the 

displacement of fuels from the end use of bottled biogas in such situations. If however the end use 

of the bottled biogas is included in the project boundary and is monitored during the crediting 

period CO2 emissions avoided by the displacement of fossil fuel can be claimed under the 

corresponding Type I methodology, e.g. AMS-I.C ìThermal energy production with or without 

electricityî. 

6. For project activities covered under paragraph 3 (c) (i), emission reductions from the 

displacement of the use of natural gas are eligible under this methodology, provided the 

geographical extent of the natural gas distribution grid is within the host country boundaries. 

 

2

 For example combusted in a prime mover such as an engine coupled to a machine such as grinding 

machine. 
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7. For project activities covered under paragraph 3 (c) (ii), emission reductions for the 

displacement of the use of fuels can be claimed following the provision in the corresponding 

Type I methodology, e.g. AMS-I.C. 

8. In particular, for the case of 3 (b) and (c) (iii), the physical leakage during storage and 

transportation of upgraded biogas, as well as the emissions from fossil fuel consumed by vehicles 

for transporting biogas shall be considered. Relevant procedures in paragraph 11 of Annex 1 of 

AMS-III.H ìMethane recovery in wastewater treatmentî shall be followed in this regard. 

9. For project activities covered under paragraph 3 (b) and (c), this methodology is applicable 

if the upgraded methane content of the biogas is in accordance with relevant national regulations 

(where these exist) or, in the absence of national regulations, a minimum of 96% (by volume). 

10. If the recovered biogas is utilized for the production of hydrogen (project activities covered 

under paragraph 3 (d)), that component of the project activity shall use the corresponding 

methodology AMS-III.O ìHydrogen production using methane extracted from biogasî. 

11. If the recovered biogas is used for project activities covered under paragraph 3 (e), that 

component of the project activity shall use corresponding methodology AMS-III.AQ ìIntroduction 

of Bio-CNG in road transportationî. 

12. New facilities (Greenfield projects) and project activities involving a change of equipment 

resulting in a capacity addition of the wastewater or sludge treatment system compared to the 

designed capacity of the baseline treatment system are only eligible to apply this methodology if 

they comply with the relevant requirements in the ìGeneral guidelines to SSC CDM 

methodologiesî. In addition the requirements for demonstrating the remaining lifetime of the 

equipment replaced, as described in the general guidelines shall be followed. 

13. The location of the wastewater treatment plant as well as the source generating the 

wastewater shall be uniquely defined and described in the PDD. 

14. Measures are limited to those that result in aggregate emissions reductions of less than or 

equal to 60 kt CO2 equivalent annually from all Type III components of the project activity. 

Boundary 

15. The project boundary is the physical, geographical site where the wastewater and sludge 

treatment takes place, in the baseline and project situations. It covers all facilities affected by the 

project activity including sites where processing, transportation and application or disposal of 

waste products as well as biogas takes place. 

16. Implementation of the project activity at a wastewater and/or sludge treatment system will 

affect certain sections of the treatment systems while others may remain unaffected. The treatment 

systems not affected by the project activity, i.e. sections operating in the project scenario under the 

same operational conditions as in the baseline scenario (e.g. wastewater inflow and COD content, 

temperature, retention time, etc.), shall be described in the PDD, but emissions from those sections 

do not have to be accounted for in the baseline and project emission calculations (since the same 
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emissions would occur in both baseline and project scenarios).3 The assessment and identification 

of the systems affected by the project activity will be undertaken ex ante, and the PDD shall justify 

the exclusion of sections or components of the system. The treatment systems (lagoons, reactors, 

digesters, etc.) that will be covered and/or equipped with biogas recovery by the project activity, 

but continue to operate with the same quality of feed inflow, volume (retention time), and 

temperature (heating) as in the baseline scenario, may be considered as not affected i.e. the 

methane generation potential4

 remains unaltered.

Baseline 

17. Wastewater and sludge treatment systems equipped with a biogas recovery facility in the 

baseline shall be excluded from the baseline emission calculations. 

18. Baseline emissions for the systems affected by the project activity may consist of: 

(i) Emissions on account of electricity or fossil fuel used (BEpower,y); 

(ii) Methane emissions from baseline wastewater treatment systems (BEww,treatment,y); 

(iii) Methane emissions from baseline sludge treatment systems (BEs,treatment,y); 

(iv) Methane emissions on account of inefficiencies in the baseline wastewater 

treatment systems and presence of degradable organic carbon in the treated 

wastewater discharged into river/lake/sea (BEww,discharge,y); 

(v) Methane emissions from the decay of the final sludge generated by the baseline 

treatment systems (BEs,final,y). 

BE y = {BE power , y + BE ww ,treatment , y + BE s,treatment , y + BE ww,dischar ge,y + BE s, final , y} (1) 

Where: 

BE y Baseline emissions in year y (tCO2e) 

BE power , y Baseline emissions from electricity or fuel consumption in year y (tCO2e) 

BE ww ,treatment , y Baseline emissions of the wastewater treatment systems affected by the 

project activity in year y (tCO2e) 

BE s,treatment , y Baseline emissions of the sludge treatment systems affected by the project 

activity in year y (tCO2e) 

 

3

 As per EB 22, annex 2 ìGuidance regarding methodological issuesî section E. 

4

 The covering of lagoons and the installation of biogas recovery equipment may result in changes in the 

operational conditions (such as temperature, COD removal, etc.) of an anaerobic treatment system. These 

changes are considered small and hence not accounted for under this methodology. 
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BE ww,dischar ge,y Baseline methane emissions from degradable organic carbon in treated 

wastewater discharged into sea/river/lake in year y (tCO2e). The value of this 

term is zero for the case 1 (b) 

BE s, final , y Baseline methane emissions from anaerobic decay of the final sludge 

produced in year y (tCO2e). If the sludge is controlled combusted, disposed in 

a landfill with biogas recovery, or used for soil application in the baseline 

scenario, this term shall be neglected 

19. Baseline emissions from electricity and fossil fuel consumption (BEpower,y) are determined 

as per the procedures described in the ìTool to calculate baseline, project and/or leakage emissions 

from electricity consumptionî and ìTool to calculate project or leakage CO2 emissions from fossil 

fuel combustionî, respectively. The energy consumption shall include all equipment/devices in the 

baseline wastewater and sludge treatment facility. If recovered biogas in the baseline is used to 

power auxiliary equipment it should be taken into account accordingly, using zero as its emission 

factor. 

20. Methane emissions from the baseline wastewater treatment systems affected by the project 

(BEww,treatment,y) are determined using the COD removal efficiency of the baseline plant: 

o ww BL CH4

i

BEww,treatment , y = ∑(Qww,i, y *CODinf low,i, y ∗η COD,BL,i ∗ MCFww,treatment ,BL,i)* B , ∗UF *GWP (2)

Where: 

Qww ,i, y Volume of wastewater treated in baseline wastewater treatment system i in 

year y (m3

). For ex ante estimation, forecasted wastewater generation volume 

or the designed capacity of the wastewater treatment facility can be used. 

However, the ex post emissions reduction calculation shall be based on the 

actual monitored volume of treated wastewater 

COD inf low ,i, y Chemical oxygen demand of the wastewater inflow to the baseline treatment 

system i in year y (t/m3

). Average value may be used through sampling with 

the confidence/precision level 90/10 

η COD,BL,i COD removal efficiency of the baseline treatment system i, determined as per 

the paragraphs 26, 27 or 28 below 

MCF ww ,treatment ,BL ,i Methane correction factor for baseline wastewater treatment systems i (MCF

values as per Table III.H.1) 

i Index for baseline wastewater treatment system 
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Bo ,ww Methane producing capacity of the wastewater (IPCC value of 0.25 kg 

CH4/kg COD)5 

UFBL Model correction factor to account for model uncertainties (0.89)6

GWPCH4 Global Warming Potential for methane (value of 21) 

If the baseline treatment system is different from the treatment system in the project scenario, the 

monitored values of the COD inflow during crediting period will be used to calculate the baseline 

emissions ex post. 

21. The Methane Correction Factor (MCF) shall be determined based on the following table: 

Table III.H.1. IPCC default values7

 for Methane Correction Factor (MCF) 

Type of wastewater treatment and discharge pathway or system MCF value 

Discharge of wastewater to sea, river or lake 0.1 

Aerobic treatment, well managed 0.0 

Aerobic treatment, poorly managed or overloaded 0.3 

Anaerobic digester for sludge without methane recovery 0.8 

Anaerobic reactor without methane recovery 0.8 

Anaerobic shallow lagoon (depth less than 2 metres) 0.2 

Anaerobic deep lagoon (depth more than 2 metres) 0.8 

Septic system 0.5 

22. Methane emissions from the baseline sludge treatment systems affected by the project 

activity are determined using the methane generation potential of the sludge treatment systems: 

s BL F CH4

j

BEtreatment ,s, y = ∑S j,BL, y ∗ MCFs,treatment ,BL, j* DOC ∗UF * DOC ∗ F ∗16 /12 ∗GWP (3)

Where: 

j BL y S , , Amount of dry matter in the sludge that would have been treated by the sludge 

treatment system j in the baseline scenario (t). For ex ante estimation, 

forecasted sludge generation volume or the designed capacity of the sludge 

treatment facility can be used. However, the ex post emissions reduction 

calculation shall be based on the actual monitored volume of treated sludge 

 

5

 Project activities may use the default value of 0.6 kg CH4/kg BOD, if the parameter BOD5,20 is used to 

determine the organic content of the wastewater. In this case, baseline and project emissions calculations 

shall use BOD instead of COD in the equations, and the monitoring of the project activity shall be based in 

direct measurements of BOD5,20, i.e. the estimation of BOD values based on COD measurements is not 

allowed. 

6

 Reference: FCCC/SBSTA/2003/10/Add.2, page 25. 

7

 Default values from chapter 6 of volume 5. Waste in 2006 IPCC Guidelines for National Greenhouse Gas 

Inventories. 
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j Index for baseline sludge treatment system 

DOCs Degradable organic content of the untreated sludge generated in the year y

(fraction, dry basis). Default values of 0.5 for domestic sludge and 0.257 for 

industrial sludge8

 shall be used 

MCF s,treatment ,BL , j Methane correction factor for the baseline sludge treatment system j (MCF

values as per Table III.H.1) 

UFBL Model correction factor to account for model uncertainties (0.89) 

DOCF Fraction of DOC dissimilated to biogas (IPCC default value of 0.5) 

F Fraction of CH4 in biogas (IPCC default of 0.5) 

If the sludge is composted, the following equation shall be applied: 

CH4

j

BEs,treatment,y = ∑S j,BL,y ∗EFcomposting∗GWP (4)

Where: 

EFcomposting Emission factor for composting organic waste (t CH4/t waste treated). 

Emission factors can be based on facility/site-specific measurements, country 

specific values or IPCC default values (Table 4.1, chapter 4, Volume 5, 2006 

IPCC Guidelines for National Greenhouse Gas Inventories). IPCC default 

value is 0.01 t CH4/ t sludge treated on a dry weight basis 

23. If the baseline wastewater treatment system is different from the treatment system in the 

project scenario, the sludge generation rate (amount of sludge generated per unit of COD removed) 

in the baseline may differ significantly from that of the project scenario. For example, it is known 

that the amount of sludge generated in aerobic wastewater systems is larger than in anaerobic 

systems, for the same COD removal efficiency. Therefore, for these cases, the monitored values of 

the amount of sludge generated during the crediting period will be used to estimate the amount of 

sludge generated in the baseline, as follows: 

PJ

BL

j BL y l PJ y SGR

SGR S S * , , = , , (5)

 

8

 The IPCC default values of 0.05 for domestic sludge (wet basis, considering a default dry matter content 

of 10%) or 0.09 for industrial sludge (wet basis, assuming dry matter content of 35%), were corrected for 

dry basis. 
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Where: 

l PJ y S , , Amount of dry matter in the sludge treated by the sludge treatment system l in 

year y in the project scenario (t) 

BL SGR Sludge generation ratio of the wastewater treatment plant in the baseline 

scenario (tonne of dry matter in sludge/t COD removed). This ratio will be 

determined as per paragraphs 26, 27 or 28 below 

SGRPJ Sludge generation ratio of the wastewater treatment plant in the project scenario 

(tonne of dry matter in sludge/t COD removed). Calculated using the 

monitored values of COD removal (i.e. CODinflow,i minus CODoutflow,i) and 

sludge generation in the project scenario 

24. Methane emissions from degradable organic carbon in treated wastewater discharged in 

e.g. a river, sea or lake in the baseline situation are determined as follows: 

BE ww ,discharge , y Qww , y GWP CH4 Bo ,ww UFBL COD ww ,discharge ,BL , y MCF ww ,BL ,discharge = ∗ * * * ∗ (6) 

Where: 

Qww , y Volume of treated wastewater discharged in year y (m3

)

UFBL Model correction factor to account for model uncertainties (0.89) 

COD ww ,discharge ,BL , y Chemical oxygen demand of the treated wastewater discharged into sea, river 

or lake in the baseline situation in the year y (t/m3

). If the baseline scenario is 

the discharge of untreated wastewater, the COD of untreated wastewater shall 

be used 

MCF ww ,BL ,discharge Methane correction factor based on discharge pathway in the baseline 

situation (e.g. into sea, river or lake) of the wastewater (fraction) (MCF 

values as per Table III.H.1) 

To determine CODww,discharge,BL,y: if the baseline treatment system(s) is different from the treatment 

system(s) in the project scenario, the monitored values of the COD inflow during crediting period 

will be used to calculate the baseline emissions ex post. The outflow COD of the baseline systems 

will be estimated using the removal efficiency of the baseline treatment systems, estimated as per 

paragraphs 26, 27 or 28 below.

25. Methane emissions from anaerobic decay of the final sludge produced are determined as 

follows: 

s final y final BL y DOC s UFBL MCF s BL final DOC F F GWP CH4 BE = S ∗ ∗ * ∗ ∗ ∗16 /12 ∗ , , , , , , (7)
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Where: 

final BL y S , , Amount of dry matter in the final sludge generated by the baseline 

wastewater treatment systems in the year y (t). If the baseline wastewater 

treatment system is different from the project system, it will be estimated 

using the monitored amount of dry matter in the final sludge generated by 

the project activity (Sfinal,PJ,y) corrected for the sludge generation ratios of 

the project and baseline systems as per equation 5 above 

MCF s,BL , final Methane correction factor of the disposal site that receives the final sludge 

in the baseline situation, estimated as per the procedures described in the 

ìTool to determine methane emissions avoided from disposal of waste at a 

solid waste disposal siteî 

UFBL Model correction factor to account for model uncertainties (0.89) 

26. In determining baseline emissions using equation 1, historical records of at least one year 

prior to the project implementation shall be used. This shall include for example the COD removal 

efficiency of the wastewater treatment systems, the amount of dry matter in sludge, power and 

electricity consumption per m3

 of wastewater treated the amount of final sludge generated per 

tonne of COD removed, and all other parameters required for determination of baseline emissions. 

27. For wastewater treatment plant that has been operating for at least three years and if one 

year of historical data is not available, the following procedures shall be followed: 

(a) All the available data in determining the required parameters (COD removal 

efficiency, specific energy consumption and specific sludge production) shall be 

used to determine the baseline emissions in year y; 

(b) An ex ante measurement campaign shall be implemented to determine the required 

parameters (COD removal efficiency, specific energy consumption and specific 

sludge production). The measurement campaign shall be implemented in the 

baseline wastewater systems for at least 10 days. The measurements should be 

undertaken during a period that is representative for the typical operation 

conditions of the systems and ambient conditions of the site (temperature, etc). 

Average values from the measurement campaign shall be used and the result shall 

be multiplied by 0.89 to account for the uncertainty range (30% to 50%). The 

parameters from the measurement campaign are used to calculate the baseline 

emission in year y; 

(c) The baseline emissions in year y is taken as the minimum between the result of (a) 

and (b). 

28. In the case of Greenfield and capacity addition projects, or existing plant without three year 

operating history, the following procedures shall be used to determine the baseline emissions: 

(1) For existing plant without three year operating history, procedures in paragraph 27 shall be 

followed; 
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(2) For Greenfield and capacity addition projects, one of the following procedures shall be 

used: 

(a) Value obtained from a measurement campaign in a comparable existing 

wastewater treatment plant i.e. having similar environmental and technological 

circumstances for example treating similar type of wastewater. Average values 

from the measurement campaign shall be used and the result shall be multiplied by 

0.89 to account for the uncertainty range (30% to 50%) associated with this 

approach. The treatment plant and wastewater source can be considered as similar 

as the baseline plant, whereby the measurement campaign can be implemented 

when following conditions can be fulfilled: 

(i) The two sources of wastewater (wastewater treated in the selected plant 

and from the project activity) are of the same type, e.g. either domestic or 

industrial wastewater; 

(ii) The selected plant and the baseline plants employ the same treatment 

technology (e.g. anaerobic lagoons or activated sludge), and the hydraulic 

retention times in their biological and physical treatment systems do not 

vary by more than 20%; and 

(iii) For project activity treating industrial wastewater, both industries have the 

same raw material and final products, and apply the same industrial 

technology. Alternatively, different industrial wastewaters may be 

considered as similar if the following requirements are fulfilled: 

• The ratio COD/BOD (related to the proportion of biodegradable 

organic matter) does not differ by more than 20%; and 

• The ratio total COD / soluble COD (related to the proportion of 

suspended organic matter, and therefore to the sludge generation 

capacity) does not differ by more than 20%. 

(b) Value provided by the manufacturer/designer of a Greenfield wastewater treatment 

plant using the same technology, demonstrated to be conservative, e.g. average values 

from the top 20 percent plants with lowest emission rate per ton COD removed among 

the plants installed in the last five years designed for the same country/region to treat 

the same type of wastewaters as the project activity. 

Project Activity Emissions 

29. Project activity emissions from the systems affected by the project activity are: 

(i) CO2 emissions from electricity and fuel used by the project facilities ( PEpower, y ); 

(ii) Methane emissions from wastewater treatment systems affected by the project 

activity, and not equipped with biogas recovery in the project scenario 

( PEww,treatment, y ); 
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(iii) Methane emissions from sludge treatment systems affected by the project activity, 

and not equipped with biogas recovery in the project situation ( PEs,treatment, y ); 

(iv) Methane emissions on account of inefficiency of the project activity wastewater 

treatment systems and presence of degradable organic carbon in treated wastewater 

( PE ww ,discharge , y ); 

(v) Methane emissions from the decay of the final sludge generated by the project 

activity treatment systems ( PEs, final , y ); 

(vi) Methane fugitive emissions due to inefficiencies in capture systems ( PE fugitive , y ); 

(vii) Methane emissions due to incomplete flaring ( PE flaring , y ); 

(viii) Methane emissions from biomass stored under anaerobic conditions which would 

not have occurred in the baseline situation (PEbiomass,y).9

⎪⎭

⎪

⎬

⎫

⎪⎩

⎪

⎨

⎧

+ +

+ + + + + =

fugitive y biomass y flaring y

power y ww treatment y s treatment y ww discharge y s final y

y PE PE PE

PE PE PE PE PE

PE

, , ,

, , , , , , , , , (8)

Where: 

PEy Project activity emissions in the year y (tCO2e) 

PEpower, y Emissions from electricity or fuel consumption in the year y (tCO2e). These 

emissions shall be calculated as per paragraph 19, for the situation of the 

project scenario, using energy consumption data of all equipment/devices 

used in the project activity wastewater and sludge treatment systems and 

systems for biogas recovery and flaring/gainful use 

 

9

 For instance in the baseline situation Palm Kernel Shells (PKS) are used as fuel in a boiler. In the project 

situation PKS is replaced by biogas captured at a wastewater treatment system. The PKS will no longer be 

used as fuel in the boiler, but sold on the market. Before it is sold it is likely it will be stored for a period 

of time (few months or longer) on site which might lead to methane emissions from anaerobic decay. 
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PEww,treatment, y Methane emissions from wastewater treatment systems affected by the project 

activity, and not equipped with biogas recovery, in year y (tCO2e). These 

emissions shall be calculated as per equation 2 in paragraph 20, using an 

uncertainty factor of 1.12 and data applicable to the project situation 

(MCFww,treatment,PJ,k and η,PJ,k,y) and with the following changed definition of 

parameters: 

MCFww,treatmen

t,PJ,k

Methane correction factor for project wastewater treatment 

system k (MCF values as per Table III.H.1) 

η,PJ,k, Chemical oxygen demand removal efficiency of the project 

wastewater treatment system k in year y (t/m3

), measured 

based on inflow COD and outflow COD in system k

PEs,treatment, y Methane emissions from sludge treatment systems affected by the project 

activity, and not equipped with biogas recovery, in year y (tCO2e). These 

emissions shall be calculated as per equations 3 and 4 in paragraph 22, using 

an uncertainty factor of 1.12 and data applicable to the project situation (Sl,PJ,y, 

MCFs,treatment,l) and with the following changed definition of parameters: 

Sl,PJ,y Amount of dry matter in the sludge treated by the sludge 

treatment system l in the project scenario in year y (t) 

MCFs,treatment,l Methane correction factor for the project sludge treatment 

system l (MCF values as per Table III.H.1) 

PEww,discharge, y Methane emissions from degradable organic carbon in treated wastewater in 

year y (tCO2e). These emissions shall be calculated as per equation 6 in 

paragraph 24, using an uncertainty factor of 1.12 and data applicable to the 

project conditions (CODww,discharge,PJ,y, MCFww,PJ,discharge) and with the following 

changed definition of parameters: 

CODww,discharg

e,PJ,y

Chemical oxygen demand of the treated wastewater 

discharged into the sea, river or lake in the project scenario in 

year y (t/m3

) 

MCFww,PJ,disch

arge

Methane correction factor based on the discharge pathway of 

the wastewater in the project scenario (e.g. into sea, river or 

lake) (MCF values as per Table III.H.1) 
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PEs, final, y Methane emissions from anaerobic decay of the final sludge produced in 

year y (tCO2e). These emissions shall be calculated as per equation 7 in 

paragraph 25, using an uncertainty factor of 1.12 and data applicable to the 

project conditions (MCFs,PJ,final, Sfinal,PJ,y). If the sludge is controlled 

combusted, disposed in a landfill with biogas recovery, or used for soil 

application in aerobic conditions in the project activity, this term shall be 

neglected, and the sludge treatment and/or use and/or final disposal shall be 

monitored during the crediting period with the following revised definition of 

the parameters: 

MCFs,PJ,final Methane correction factor of the disposal site that receives the 

final sludge in the project situation, estimated as per the 

procedures described in the ìTool to determine methane 

emissions avoided from disposal of waste at a solid waste 

disposal siteî 

Sfinal,PJ,y Amount of dry matter in final sludge generated by the project 

wastewater treatment systems in the year y (t) 

PEfugitive, y Methane emissions from biogas release in capture systems in year y, 

calculated as per paragraph 30 (tCO2e) 

PEflaring, y Methane emissions due to incomplete flaring in year y (tCO2e). For ex ante

estimation, baseline emission calculation for wastewater and/or sludge 

treatment (i.e. equation 2 and/or equation 3) can be used but without the 

consideration of GWP for CH4. However, the ex post emission reduction 

shall be calculated as per theìTool to determine project emissions from flaring 

gases containing methaneî by using actual monitored data 

PEbiomass, y

Methane emissions from biomass stored under anaerobic conditions. If 

storage of biomass under anaerobic conditions takes place in the project and 

does not occur in the baseline , methane emissions due to anaerobic decay of 

this biomass shall be considered and be determined as per the procedure in the 

ìTool to determine methane emissions avoided from disposal of waste at a 

solid waste disposal siteî (tCO2e) 

30. Project activity emissions from methane release in capture systems are determined as 

follows: 

(a) Based on the methane emission potential of wastewater and/or sludge: 

PE fugitive , y = PE fugitive ,ww , y + PE fugitive ,s, y (9)

Where: 

PE fugitive ,ww , y Fugitive emissions through capture inefficiencies in the anaerobic wastewater 

treatment systems in the year y (tCO2e) 

PE fugitive ,s, y Fugitive emissions through capture inefficiencies in the anaerobic sludge 

treatment systems in the year y (tCO2e) 
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PE fugitive ww y CFE ww MEP ww treatment y GWP CH4 = − ∗ ∗ , , , , (1 ) (10)

Where: 

CFEww Capture efficiency of the biogas recovery equipment in the wastewater 

treatment systems (a default value of 0.9 shall be used) 

MEP ww ,treatment , y Methane emission potential of wastewater treatment systems equipped with 

biogas recovery system in year y (t) 

removed PJ k y ww treatment PJ k

k

MEPww,treatment,y = Qww,y*Bo,ww ∗UFPJ*∑ COD , , , ∗MCF , , , (11)

Where: 

CODremoved ,PJ ,k , y The chemical oxygen demand removed10 by the treatment system k of the 

project activity equipped with biogas recovery in the year y (t/m3

) 

MCF ww ,treatment ,PJ ,k Methane correction factor for the project wastewater treatment system k

equipped with biogas recovery equipment (MCF values as per Table III.H.1) 

UFPJ Model correction factor to account for model uncertainties (1.12) 

PE fugitive s y CFE s MEP s treatment y GWP CH4 = − ∗ ∗ , , , , (1 ) (12)

Where: 

CFEs Capture efficiency of the biogas recovery equipment in the sludge treatment 

systems (a default value of 0.9 shall be used) 

MEP s,treatment , y Methane emission potential of the sludge treatment systems equipped with a 

biogas recovery system in year y (t) 

( )* * 16/12 , , , , , , , MEP = ∑ S ∗MCF DOC ∗UF DOC ∗F ∗ s PJ F

l

s treatment y l PJ y s treatment PJ l (13) 

Where: 

l PJ y S , , Amount of sludge treated in the project sludge treatment system l equipped 

with a biogas recovery system (on a dry basis) in year y (t) 

MCF s,treatment ,PJ ,l Methane correction factor for the sludge treatment system equipped with 

biogas recovery equipment (MCF values as per Table III.H.1) 

UFPJ Model correction factor to account for model uncertainties (1.12) 

 

10 Difference between the inflow COD and the outflow COD. 
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(b) Optionally a default value of 0.05 m3 biogas leaked/m3 biogas produced may be used as an 

alternative to calculations per equation 9 to 13. 

Leakage 

31. If the technology is using equipment transferred from another activity, leakage effects at 

the site of the other activity are to be considered and estimated (LEy). 

Emission Reduction 

32. For all scenarios in paragraph 1, i.e. 1 (a) to 1 (f), emission reductions shall be estimated 

ex ante in the PDD using the equations provided in the baseline, project and leakage emissions 

sections above. Emission reductions shall be estimated ex ante as follows: 

( ) ER y ,ex ante = BE y ,ex ante − PE y ,ex ante + LE y ,ex ante (14)

Where: 

ER y ,ex ante Ex ante emission reduction in year y (tCO2e) 

LE y ,ex ante Ex ante leakage emissions in year y (tCO2e) 

PE y , ex ante Ex ante project emissions in year y calculated as paragraph 29 (tCO2e) 

BE y ,ex ante Ex ante baseline emissions in year y calculated as per paragraph 18 (tCO2e) 

33. Ex post emission reductions shall be determined for case 1 (a) and 1 (e) as per 

paragraph 36. For cases 1 (b), 1 (c), 1 (d) and 1 (f), ex post emission reductions shall be based on 

the lowest value of the following, as per paragraph 34: 

(i) The amount of biogas recovered and fuelled or flared (MDy) during the crediting 

period, that is monitored ex post; 

(ii) Ex post calculated baseline, project and leakage emissions based on actual 

monitored data for the project activity. 

34. For cases 1 (b), 1 (c), 1 (d) and 1 (f): it is possible that the project activity involves 

wastewater and sludge treatment systems with higher methane conversion factors (MCF) or with 

higher efficiency than the treatment systems used in the baseline situation. Therefore the emission 

reductions achieved by the project activity is limited to the ex post calculated baseline emissions 

minus project emissions using the actual monitored data for the project activity. The emission 

reductions achieved in any year are the lowest value of the following: 

( ))

min(( ),

, , ,

, , , ,

y power y biomass y y ex post

y ex post y ex post y ex post y ex post

MD PE PE LE

ER BE PE LE

− − −

= − − (15)
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Where: 

ER y ,ex post Emission reductions achieved by the project activity based on monitored values 

for year y (tCO2e) 

BE y ,ex post Baseline emissions calculated as per paragraph 18 using ex post monitored values 

PE y ,ex post Project emissions calculated as per paragraph 29 using ex post monitored values 

MD y Methane captured and destroyed/gainfully used by the project activity in the year y

(tCO2e)

35. In the case of flaring/combustion MDy will be measured using the conditions of the flaring 

process: 

MDy BGburnt y wCH4 y DCH4 FE GWPCH4 * * * * = , , (16) 

Where: 

BG burnt , y Biogas11 flared/combusted in year y (m3

) 

wCH4 , y Methane content13 of the biogas in the year y (volume fraction) 

DCH4 Density of methane at the temperature and pressure of the biogas in the year y

(t/m3) 

FE Flare efficiency in year y (fraction). If the biogas is combusted for gainful 

purposes, e.g. fed to an engine, an efficiency of 100% may be applied 

36. For the cases listed in paragraph 1 such as: 

(a) Substitution of an aerobic wastewater or sludge treatment system with an anaerobic 

treatment system with methane recovery and combustion; and 

(b) Introduction of an anaerobic wastewater treatment system with methane recovery 

and combustion to an untreated wastewater stream. 

The emission reduction achieved by the project activity (ex post) will be the difference between the 

baseline emissions and the sum of the project emissions and leakage. 

( ) ER y = BE y ,ex post − PE y ,ex post + LE y ,ex post (17)

The historical records of electricity and fuel consumption, the COD content of untreated and 

treated wastewater, and the quantity of sludge produced by the replaced units will be used for the 

baseline calculation. 

 

11 Biogas volume and methane content measurements shall be on the same basis (wet or dry). 
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In case (a), if the volumetric flow and the characteristic properties (e.g. COD) of the inflow and 

outflow of the wastewater are equivalent in the project and the baseline scenarios (i.e. the project 

and baseline systems have the same efficiency for COD removal for wastewater treatment), then 

the higher energy consumption and sludge generation in the baseline scenario are the only 

significant differences contributing to emissions reductions in the project case. In this case, the 

emission reductions can be calculated as the difference between the historical energy consumption 

of the replaced unit and the recorded energy consumption of the new system, plus the difference in 

emissions from sludge treatment and/or disposal. Project emissions from fugitive emissions and 

incomplete flaring (PEfugitive,y, PEflaring,y) shall also be considered in the calculation of the emission 

reductions, however the emissions from the wastewater outflow and sludge (PEww,discharge,y, 

PEs,final,y) may be disregarded, if they are equivalent in the baseline and project scenarios. 
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Monitoring 37. Relevant parameters shall be monitored as indicated in the Table III.H.2. below. The applicable requiremen

SSC CDM Methodologiesî (e.g. calibration requirements, sampling requirements) are also an integral part of the mo

therefore shall be referred by the project participants. 

Table III.H.2. Parameters for monitoring during the crediting perio

No. Parameter Description Unit Monitoring/ 

recording 

Frequency 

Measure

1 Qww ,i, y The flow of wastewater m3/month Monitored 

continuously (at least hourly measurements are undertaken, if less, confidence/precision level of 90/10 shall be attained) 

Measurements are un

2 CODww,untreated,y, 

CODww,treated,y, 

CODww,discharge,PJ,y

The chemical oxygen demand of the wastewater before and after the treatment system affected by the project activity 

t COD/m3 Samples and 

measurements shall ensure a 90/10 confidence/precision level 

Measure the COD acstandards. COD is m
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No. Parameter Description Unit Monitoring/ 

recording 

Frequency 

Measure

3 l PJ y S , , , Sfinal,PJ,y, Amount of dry matter in 

the sludge 

t Monitoring of 100% 

of the sludge amount through continuous or batch measurements and moisture content through representative sampling to ensure the 90/10 confidence/precision level 

Measure the total qua(m3) and density or d

the sludge amount (wto determine the moisamount on dry basis. If the methane emissisludge are to be neglecombusted, disposed used for soil applicatbe monitored during If the baseline emissisludge generated by twithout methane recoclearly defined, and v
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No. Parameter Description Unit Monitoring/ 

recording 

Frequency 

Measure

4 BG burnt , y Biogas volume in year y m3 Monitored 

continuously (at least hourly measurements are undertaken, if less, confidence/precision level of 90/10 shall be attained) 

In all cases, the amouotherwise utilized (e.grid or distributed via monitored ex post, us

streams flared and futhe two fractions can biogas recovered, witbiogas before the sepshall be carried out clbiogas flow measurem

5 wCH4 , y Methane content in biogas 

in the year y

% The fraction of metha

continuous analyser omeasurements at a 90measured using equipcontent in the biogas biogas based on meassuch as CO2 is not pe

measurement shall be system where a bioga
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No. Parameter Description Unit Monitoring/ 

recording 

Frequency 

Measure

6 T Temperature of the biogas oC Shall be measured at 

the same time when methane content in biogas ( wCH4 , y ) is 

measured 

The temperature of thof the methane combmeasures flow, pressuthe normalised flow omonitoring of pressur

7 P Pressure of the biogas Pa Shall be measured at 

the same time when methane content in biogas ( wCH4 , y ) is 

measured 

The pressure of the gthe methane combustmeasures flow, pressuthe normalised flow omonitoring of pressur

8 The flare efficiency % As per the ìTool to d

gases containing Metcarried out to ensure 

9 Parameters related to 

emissions from electricity and/or fuel consumption in year y

 As per the procedure 

and/or leakage emissìTool to calculate pro

fuel combustionî. Arelevant electrical equ10% to account for dannum 
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No. Parameter Description Unit Monitoring/ 

recording 

Frequency 

Measure

10 Parameters related to 

methane emissions from biomass stored under anaerobic conditions which does not occur in the baseline situation 

tCO2e As per the latest vers

emissions avoided frodisposal siteî 
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Project activity under a programme of activities 

38. The following conditions apply for use of this methodology in a project activity under a 

programme of activities:

In case the project activity involves the replacement of equipment, and the leakage effect of the use 

of the replaced equipment in another activity is neglected, because the replaced equipment is 

scrapped, an independent monitoring of scrapping of replaced equipment needs to be implemented. 

The monitoring should include a check if the number of project activity equipment distributed by 

the project and the number of scrapped equipment correspond with each other. For this purpose 

scrapped equipment should be stored until such correspondence has been checked. The scrapping 

of replaced equipment should be documented and independently verified. 
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Annex 1 

PROVISIONS FOR UPGRADATION AND DISTRIBUTION OF BIOGAS 

Project Boundary 

1. In case of project activities covered under paragraph 3 (b) and (c),12 if the project activity 

involves bottling of biogas the project boundary includes the upgrade and compression 

installations, the dedicated piped network/natural gas distribution grid for distribution of biogas 

from the wastewater treatment plant to the end user sites and all the facilities and devices connected 

directly to it. 

Baseline 

2. In case of project activities covered under paragraph 3 (c) (i) the baseline emissions for 

upgraded biogas injection (BEinjection,y) are determined as follows: 

BEinjection y Eug y CEF NG * , = , (1) 

Where: 

BE injection , y Baseline emissions for injection of upgraded biogas into a natural gas distribution 

grid in year y (tCO2e) 

Eug , y Energy delivered from the upgraded biogas in the project activity to the natural 

gas distribution grid in year y (TJ) 

CEFNG Carbon emission factor of natural gas (tCO2e/TJ); (Accurate and reliable local or 

national data may be used where available, otherwise appropriate IPCC default 

values shall be used) 

3. The energy delivered from the upgraded biogas in the project activity to the natural gas 

distribution grid in year y (Eug,y) is calculated as follows: 

ug y Eug y Qug y NCV , , = , * (2) 

Where:

Qug , y Quantity of upgraded biogas displacing the use of natural gas in the natural gas 

distribution grid in year y (kg or m3

) 

NCVug, y Net calorific value of the upgraded biogas in year y (TJ/kg or TJ/m3

) 

 

12 These are references to the section ìtechnology/measureî in the methodology including upgrading of 

biogas before distribution to the quality of natural gas for use as fuel or for bottling or for injection into a 

natural gas distribution system. The eligible biogas upgrading technologies covered in this annex include: 

(1) Pressure Swing Adsorption; (2) Absorption with/without water circulation; (3) Absorption with water, 

with or without water recirculation (with or without recovery of methane emissions from discharge). For 

those technologies, please refer to annex 1 of the approved methodology AM0053 ìBiogenic methane 

injection to a natural gas distribution gridî/Version 01.1 regarding the description of these technologies 

Project proponent may submit a request for revision to include more technology options. 
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4. The quantity of upgraded biogas displacing the use of natural gas in the natural gas 

distribution grid in year y is calculated as follows: 

min( , ) Qug,y = Qug,in,y Qcap,CH4,y (3)

Where: 

Qug ,in , y Quantity of upgraded biogas injected into the natural gas distribution grid in year y 

(kg or m3

) 

Qcap ,CH4 , y Quantity of methane captured at the wastewater treatment source facility(ies) in 

year y (kg or m3

) 

5. The quantity of methane captured at the waste water treatment source facility(ies) is 

calculated as follows: 

Qcap ,CH4 , y wCH4 ,ww Qcap ,biogas , y = * (4)

Where: 

wCH4 ,ww Methane fraction of biogas as monitored at the outlet of the wastewater treatment 

source facility(ies) (kg or m3

 CH4/kg or m3 of biogas) 

Qcap ,biogas , y Monitored amount of biogas captured at the source facility(ies) in year y (kg or 

m3

) 

Project activity emission 

6. In case of project activities covered under paragraph 3 (b) and 3 (c) the following project 

emissions related to the upgrading and compression of the biogas (PEprocess,y) shall be included: 

(i) CO2 emissions from electricity and fuel used by the upgrading facilities (tCO2e); 

(ii) Methane emissions from the discharge of the upgrading equipment (tCO2e); 

(iii) Fugitive methane emissions from leaks in compression equipment (tCO2e); 

(iv) Emissions on account of vent gases from upgrading equipment (tCO2e). 

PE process , y = PE power ,upgrade , y + PE ww ,upgrade , y + PE CH4 ,equip , y + PE ventgas , y (5)

Where: 

PE process , y Project emissions related to the upgrading and compression of the biogas in 

year y (tCO2e) 

PEpower,upgrade, y CO2 emissions from electricity and fuel used by the upgrading facilities (tCO2e), 

as per paragraph 19 of AMS-III.H 

PE ww ,upgrade , y Emissions from methane contained in any waste water discharge of upgrading 

installation in year y (tCO2e) 
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PE CH4 ,equip , y Emissions from compressor leaks in year y (tCO2e) 

PE ventgas , y Emissions from venting gases retained in upgrading equipment in year y (tCO2e) 

7. Project activity emissions from methane contained in waste water discharge of upgrading 

installation are determined as follows: 

[ ] PEww,upgrade,y = Qww,upgrade,y

∗ CH4 ww,upgrade,y∗GWPCH4 (6)

Where: 

Qww ,upgrade , y Volume of wastewater discharge from upgrading installation in year y

[ ] CH4 ww,upgrade, y

Dissolved methane contained in the wastewater discharge in year y

8. Project activity emissions from compressor leaks are determined as follows: 

= ∑

equipment

PECH4,equip, yGWPCH4* wCH4,stream, y* EFequipment*Tequipment, y ) 1000

1 * ( (7)

Where: 

wCH4,stream, y Average methane weight fraction of the gas (kg-CH4/kg) in year y

Tequipment , y Operation time of the equipment in hours in year y (in absence of detailed 

information, it can be assumed that the equipment is used continuously, as a 

conservative approach) 

EFequipment Leakage rate for fugitive emissions from the compression technology as per 

specification from the compressor manufacturer in kg/hour/compressor. If no 

default value from the technology provider is available, the approach below 

shall be used 

Fugitive methane emissions occurring during the recovery and processing of gas may in some 

projects be small, but should be estimated as a conservative approach. Emission factors may be 

taken from the 1995 Protocol for Equipment Leak Emission Estimates, published by EPA.13

Emissions should be determined for all relevant activities and all equipment used for the upgrading 

of biogas (such as valves, pump seals, connectors, flanges, open-ended lines, etc.). 

 

13 Please refer to the document US EPA-453/R-95-017 at: 

<http://www.epa.gov/ttn/chief/efdocs/equiplks.pdf>, accessed on 23/10/2007. 
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The following data needs to be obtained: 

(1) The number of each type of component in a unit (valve, connector, etc.); 

(2) The methane concentration of the stream; 

(3) The time period each component is in service. 

The EPA approach is based on average emission factors for Total Organic Compounds (TOC) in a 

stream and has been revised to estimate methane emissions. Methane emissions are calculated for 

each single piece of equipment by multiplying the methane concentration with the appropriate 

emission factor from Table III.H.2 below. 

Table III.H.2. Methane emission factors for equipment14

Equipment type Emission Factor (kg/hour/ source) for 

methane 

Valves 4.5E-0.3 

Pump seals 2.4E-0.3 

Others15 8.8E-0.3 

Connectors 2.0E-0.4 

Flangs 3.9E-0.4 

Open ended lines 2.0E-0.3 

9. Project activity emissions from venting gases retained in upgrading equipment do not have 

to be considered if vent gases (PEvent gas,y) are channeled to storage bags. In case vent gases are 

flared, emissions due to the incomplete or inefficient combustion of the gases will be calculated 

using the ìTool to determine project emissions from flaring gases containing methaneî, as follows: 

1000

*(1 , )*

8760

1

, , CH4 flare h

h

ventgas y RG h

GWP PE = ∑TM −η =

 (8) 

Where: 

TMRG, h Mass flow rate of methane in the residual gas in hour h (kg/h) 

ηflare, h Flare efficiency in hour h 

In case vent gases are not flared the ìTool to determine project emissions from flaring gases 

containing methaneî will be used, without considering measurements and calculations for the flare 

efficiency, which will be assumed to be zero. In this case, emissions due to the vent gases will be: 

 

14 Please refer to the document US EPA-453/R-95-017 Table 2.4, page 2-15, accessed on 23/10/2007. 

15 The emission factor for ìotherî equipment type was derived from compressors, diaphragms, drains, dump 

arms, hatches, instruments, meters, pressure relief valves, polished rods, relief valves and vents. This 

ìotherî equipment type should be applied for any equipment type other than connectors, flanges, openended lines, pumps or valves. 
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1000

*

8760

1

, , CH4

h

y ventgas RG h

GWP PE ∑TM

=

= (9)

Alternatively, in case vent gases are directly vented to the atmosphere, it may also be calculated by 

conservatively calculating the mass of the gases vented based on the volume, pressure and 

temperature of gas retained in upgrading equipment. This mass should be multiplied with the 

frequency with which it is vented and assuming that the vented gas is pure methane. 

In order to account for emissions that occur when the upgrade facility is shut down due to 

maintenance, repair work or emergencies one of the alternatives proposed above should be used to 

calculate and include emissions from flaring or venting. 

10. In case of project activities covered under paragraph 3 (c) (ii) emissions due to physical 

leakage of upgraded biogas from the dedicated piped network (PEleakage,pipeline,y) shall be determined 

as follows: 

PE leakage pipeline y Qmethane pipeline y LR pipeline GWP CH4 = ∗ ∗ , , , , (10)

Where: 

PE leakage , pipeline , y Emissions due to physical leakage from the dedicated piped network in year y

(tCO2e) 

Qmethane , pipeline , y Total quantity of methane transported in the dedicated piped network in year y

(m3

) 

LR pipeline Physical leakage rate from the dedicated piped network (if no project-specific 

values can be identified a conservative default value of 0.0125 Gg per 106

 m3 of 

utility sales shall be applied16) 

Leakage emissions 

11. In case of project activities covered under paragraph 3 (b) and the users of the bottles filled 

with upgraded biogas are not included in the project boundary then the following leakage 

emissions shall be included and calculated as follows: 

(a) Emissions due to physical leakage of biogas from the bottles during storage, 

transport etc. until final end use (tCO2e); 

(b) Emissions due to fossil fuel use for transportation of bottles; biogas filled bottles to 

the end users and the return of empty bottles to the filling site (tCO2e). 

LE bottling , y = LE leakage ,bb , y + LE trans , y (11) 

 

16 2006 IPCC Guidelines for National Greenhouse Gas Inventories, Volume 2, chapter 4, Table 4.2.5 

provides default values for fugitive emissions from gas operations in developing countries. The default 

values provided for fugitive emissions for the distribution of natural gas to end users range from 1.1 E-3 to 

2.5 E-3 Gg per 106

 m3 of utility sales. The uncertainty in this value is -20% to 500%. A conservative 

value of 2.5 E-3 * 500% = 0.0125 Gg per 106

 m3 of utility sales shall be taken. 
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Where: 

LE bottling , y Leakage emissions project activities involving bottling of biogas in year y

(tCO2e) 

LE leakage ,bb , y Emissions due to physical leakage from biogas bottles in year y (tCO2e) 

LEtrans, y Emissions due to fossil fuel use for transportation of bottles; biogas filled bottles 

to the end users and the return of empty bottles to the filling site in year y

(tCO2e) 

12. Leakage emissions due to physical leakage from biogas bottles are determined as follows: 

LEleakage ,bb , y Qmethane ,bb , y LRbb GWP CH 4 = ∗ ∗ (12)

Where: 

Qmethane ,bb , y Total quantity of methane bottled in year y (m3

) 

LRbb Physical leakage rate from biogas bottles (if no project-specific values can be 

identified a default value of 1.25% shall be applied)17

13. Leakage emissions due to fossil fuel use for transportation of bottles (biogas filled bottles 

to the end users and the return of empty bottles to the filling site) are determined as below. If some 

of the locations of the end-users are unknown a conservative approach assuming transport 

emissions of 250 km, shall be used. 

2

,

,

, bb CO

bb y

bb y

trans y DAF EF

CT

Q PE ∗ ∗ ⎟

⎟

⎠

⎞

⎜

⎜

⎝

⎛ = (13)

Where: 

Qbb , y Total freight volume of upgraded biogas in bottles transported in year y (m3

) 

CT bb , y Average truck freight volume capacity for the transportation of bottles with 

upgraded biogas (m3

/truck) 

DAFbb Aggregated average distance for bottle transportation; biogas filled bottles to the 

end users and the return of empty bottles to the filling site (km/truck) 

EFCO2 CO2 emission factor from fuel use due to transportation (tCO2/km) 

 

17 Victor (1989) Leaking Methane from Natural Gas Vehicles: Implication for Transportation Policy in the 

Greenhouse Era, in Climatic Change 20: 113-141, 1992 and American Gas Association (1986), 'Lost and 

Unaccounted for Gas', Planning and Analysis issues, issue brief 1986-28, p. 3. 
UNFCCC/CCNUCC 

CDM ñ Executive Board III.H./Version 16

Sectoral Scope: 13 

EB 58

Indicative simplified baseline and monitoring methodologies 

for selected small-scale CDM project activity categories 

III.H. Methane recovery in wastewater treatment (cont) 

30/32 

Monitoring 

14. The project proponents shall maintain a biogas (or methane) balance based on: 

(a) Continuous measurement of the amount of biogas captured at the wastewater 

treatment system; 

(b) Continuous measurement of the amount of biogas used for various purposes in the 

project activity: e.g. heat, electricity, flare, hydrogen production, injection into 

natural gas distribution grid, etc. The difference is considered as loss due to 

physical leakage and deducted from the emission reductions. 

15. In case of project activities covered under paragraph 3 (c) the quantity of biogas, 

temperature, pressure and concentration of methane in the biogas injected into the natural gas 

grid/distributed via the dedicated piped network shall be measured continuously using certified 

equipment. The net calorific value (NCV) shall be measured directly from the gas stream using an 

online Heating Value Meter or calculated based on the measured methane content using the NCV 

of methane. This measurement must be in mass or volume basis and the project participants shall 

ensure that units of the measurements of the amount of biogas injected and of the net calorific 

value are consistent. The methane content of the injected or transported biogas shall always be in 

accordance with national regulations or, in absence of national regulations, 96% (by volume) or 

higher. Biogas injected or transported with inferior methane content shall be excluded from the 

emission reduction calculations. 

16. In case of project activities covered under paragraph 3 (b) and 3 (c), the following 

parameters shall be monitored and recorded: 

(a) The volume of discharge into the desorption pond from the upgrading installation 

(Qww,upgrade,y), monitored continuously; 

(b) The methane content ([CH4]ww,upgrade,y) of the discharge water from the upgrade 

facility, samples are taken at least every six months during normal operation of the 

facility; 

(c) The annual operation time of the compressor and each piece of equipment in the 

biogas upgrading and compression installations in hours (Tequipment,y). In case this 

information is not available it shall be assumed that the upgrading installation and 

compressor is used continuously; 

(d) The quantity, pressure and composition of the bottled biogas, biogas injected into a 

natural grid or transported via a dedicated piped network; monitored continuously 

using flow meters and regularly calibrated methane monitors. The pressure of the 

biogas shall be regulated and monitored using a regularly calibrated pressure 

gauge. The methane content of the biogas shall always be in accordance with 

national regulations or, in absence of national regulations, 96% (by volume) or 

higher in order to ensure that biogas could readily be used as a fuel, inferior 

methane content shall be excluded from the emission reduction calculations; 
UNFCCC/CCNUCC 

CDM ñ Executive Board III.H./Version 16

Sectoral Scope: 13 

EB 58

Indicative simplified baseline and monitoring methodologies 

for selected small-scale CDM project activity categories 

III.H. Methane recovery in wastewater treatment (cont) 

31/32 

(e) In case vent gases are calculated using the ìTool to determine project emissions 

from flaring gases containing methaneî, the monitoring criteria contained in this 

tool shall be used. In case this tool is not used and the alternative approach in 

paragraph 9 of this annex is used, then temperature and pressure of gas retained in 

upgrading equipment shall be measured continuously and their values before the 

venting process are used, together with the volume capacity of the installation, to 

estimate the amount of methane released during the venting process; 

(f) During the periods when the biogas upgrading facility is closed due to scheduled 

maintenance or repair of equipment or during exigencies, project participants 

should ensure that the captured biogas is flared at the site of its capture using an 

(emergency) flare. Appropriate monitoring procedures should be established to 

monitor this emergency flare; 

(g) In case of project activities covered under paragraph 3 (b) the number and volume 

of biogas bottles produced and transported, the average truck capacity (CTbb,y) and 

the average aggregated distance for transporting the bottled biogas (DAFbb). 

- - - - - 

History of the document 

Version Date Nature of revision 

16 EB 58, Annex 22 

26 November 2010 

To include additional guidelines pertaining to transport of biogas (e.g. 

by trucks) and biogas application for transportation; 

To clarify the conditions under which the measurement campaign can 

be used for baseline emissions determination. 

15 EB 55 Annex 34 

30 July 2010 

To clarify the criteria to be satisfied for the baseline lagoon treatments 

systems under the methodology; 

To include the monitoring table with the required frequency of 

measurements and options for collection and recording of data. 

14 EB 53, Annex 17 

26 March 2010 

To include additional clarification on the monitoring requirements of 

biogas. 

13 EB 48, Annex 21 

17 July 2009 

To include additional eligible technologies for upgrading biogas for 

bottling or feeding to natural gas distribution grid. Include an option to 

use the calculated net calorific value (NCV) of biogas based on 

methane content measurement instead of directly monitoring NCV 

using a NCV meter. 

12 EB 47, Annex 26 

28 May 2009 

To include additional guidance on use of methane generation potential 

based on Biochemical Oxygen Demand (BOD5,20). 

11 EB 46, Annex 22 

25 March 2009 

To clarify the methods for determination of baseline for Greenfield 

projects; 

To specify minimum requirements concerning sludge removal interval 

in the baseline anaerobic lagoon; Further guidance on measuring 

equipment for biogas pressure, temperature and flow rate. 
UNFCCC/CCNUCC 

CDM ñ Executive Board III.H./Version 16

Sectoral Scope: 13 

EB 58

Indicative simplified baseline and monitoring methodologies 

for selected small-scale CDM project activity categories 

III.H. Methane recovery in wastewater treatment (cont) 

32/32 

Version Date Nature of revision 

10 EB 42, Annex 17 

26 September 2008 

Additional guidance on baseline determination and project emission 

calculations; 

Restructured, provisions related to methane correction factor and 

related uncertainties were revised. 

09 EB 38, Annex 10 

14 March 2008 

Expand applicability to include pipeline transport of the recovered and 

upgraded biogas; 

Additional guidance on sequential treatment of wastewater in 

anaerobic lagoons. 

08 EB 36, Annex 24 

30 November 2007 

Expand applicability to bottling of recovered biogas; 

Additional guidance on emissions from dissolved methane in the 

treated wastewater; 

Guidance on use of IPCC default factors for the degradable organic 

content of sludge. 

07 EB 35, Annex 29 

19 October 2007 

Expand the applicability to allow recovered biogas to be used for 

hydrogen production. 

06 EB 33, Annex 35 

27 July 2007 

Additional leakage guidance to allow for application under a 

programme of activities (PoA). 

05 EB 31, Annex 27 

04 May 2007 

To exclude scope 15 from the methodology 

04 EB 28, Annex 26 

15 December 2006 

Broaden the applicability to include sequential stage of anaerobic 

wastewater treatment; 

Additional guidance based on 2006 IPCC Guidelines for National 

Greenhouse Gas Inventories on the following: 

(a) Methane correction factor (MCF) determined by wastewater 

discharge pathways or type of treatment; 

(b) Default values for sludge treatment, particularly for degradable 

organic carbon (DOC) and methane correction factor (MCF). 

03 EB 25, Annex 28 

21 July 2006 

Clarify the inclusion of methane emission factor in the equation for 

baseline calculations. 

02 EB 24, 10 May 2006 

paragraph 64 of the 

report 

The Board at its twenty-fourth meeting noted that Type III project 

activities might be able to achieve significant emission reductions, 

without exceeding the direct emissions limits i.e. 15 kilo tonnes CO2e 

applicable at the time. As an interim solution, the Board agreed to 

include the following text in all Type III categories: ìThis category is 

applicable for project activities resulting in annual emission reductions 

lower than 25,000 tonnes CO2e. If the emission reduction of a project 

activity exceeds the reference value of 25,000 tonnes CO2e in any 

year of the crediting period, the annual emission reduction for that 

particular year is capped at 25,000 tonnes CO2e.î 

01 EB 23, Annex 23 

24 February 2006 

Initial adoption. 

Decision Class: Regulatory 

Document Type: Standard 

Business Function: Methodology