18 Study on the Quantitative Evaluation of Greenhouse Gas (GHG) …
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18.2.2.2 Selection of Sludge Treatment Process
According to the Guideline on Best Available Technologies of Pollution Prevention and Control for Treatment and Disposal of Sludge from Municipal Wastewater
Treatment Plant (MEPPRC 2010), three typical sludge treatment processes (landfill,
composting, and combustion) were analyzed.
18.2.3 Sources of Estimated Input Data
This study analyzed the theoretical estimation of GHG emissions from sewagesludge treatment scenarios in China. The estimated input data were obtained from
national/industrial standards, different technical guides, and environment assessment
reports. Some parameters used in this study were shown in Table 18.2.
A 40,000 m
3 /day sewage treatment capacity was used to analyze different
scenarios, as influent flow rates of small-scale WWTPs (≤40,000 m
3 /day)
(MOHURD 2006) account for 81.1% of the total WWTPs (MEPPRC 2015), which
is the mainstream treatment capacity of WWTPs built in China.
The effluent, which reflects the water quality of treated sewage, should be under
strict control before being discharged into natural waters, such as rivers and lakes.
The highest discharge standard of WWTPs in China, that is 1A-level standard
(Table 18.2), was used for GHG emissions calculation.
18.3 Estimation Procedure of Ghg Emissions
from Sewage-Sludge Treatment System
The sewage-sludge treatment system includes a sewage treatment process and a
sludge treatment process; furthermore, GHGs can be classified into direct emissions
and indirect emissions based on different emission sources. Direct emissions of
GHGs include CO 2 converted by organic matter in the biotreatment process, CH 4
emitted during the anaerobic process and sludge treatment, and N 2 O emitted during
biological nitrogen removal. Indirect emissions of GHGs mainly include electricity
consumption of mechanical equipment (such as lifting unit, aeration unit, and sludge
treatment unit) and chemicals consumption (such as PAC and PAM) during treatment
process.
In this study, estimation method of direct emissions of CO 2 and N 2 O was based
on mass balance and active sludge/anaerobic digester model (AS/AD). Indirect GHG
emissions from sewage treatment and GHG emissions from sludge treatment were
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18.2.2.2 Selection of Sludge Treatment Process
According to the Guideline on Best Available Technologies of Pollution Prevention and Control for Treatment and Disposal of Sludge from Municipal Wastewater
Treatment Plant (MEPPRC 2010), three typical sludge treatment processes (landfill,
composting, and combustion) were analyzed.
18.2.3 Sources of Estimated Input Data
This study analyzed the theoretical estimation of GHG emissions from sewagesludge treatment scenarios in China. The estimated input data were obtained from
national/industrial standards, different technical guides, and environment assessment
reports. Some parameters used in this study were shown in Table 18.2.
A 40,000 m
3 /day sewage treatment capacity was used to analyze different
scenarios, as influent flow rates of small-scale WWTPs (≤40,000 m
3 /day)
(MOHURD 2006) account for 81.1% of the total WWTPs (MEPPRC 2015), which
is the mainstream treatment capacity of WWTPs built in China.
The effluent, which reflects the water quality of treated sewage, should be under
strict control before being discharged into natural waters, such as rivers and lakes.
The highest discharge standard of WWTPs in China, that is 1A-level standard
(Table 18.2), was used for GHG emissions calculation.
18.3 Estimation Procedure of Ghg Emissions
from Sewage-Sludge Treatment System
The sewage-sludge treatment system includes a sewage treatment process and a
sludge treatment process; furthermore, GHGs can be classified into direct emissions
and indirect emissions based on different emission sources. Direct emissions of
GHGs include CO 2 converted by organic matter in the biotreatment process, CH 4
emitted during the anaerobic process and sludge treatment, and N 2 O emitted during
biological nitrogen removal. Indirect emissions of GHGs mainly include electricity
consumption of mechanical equipment (such as lifting unit, aeration unit, and sludge
treatment unit) and chemicals consumption (such as PAC and PAM) during treatment
process.
In this study, estimation method of direct emissions of CO 2 and N 2 O was based
on mass balance and active sludge/anaerobic digester model (AS/AD). Indirect GHG
emissions from sewage treatment and GHG emissions from sludge treatment were