Towards a benchmarking tool for minimizing wastewater utility greenhouse gas footprints

2012 ◽  
Vol 66 (11) ◽  
pp. 2483-2495 ◽  
Author(s):  
L. Guo ◽  
J. Porro ◽  
K. R. Sharma ◽  
Y. Amerlinck ◽  
L. Benedetti ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Greenhouse Gas ◽  
Ghg Emissions ◽  
Treatment Plant ◽  
N2o Emission ◽  
Mitigation Strategies ◽  
N2o Emissions ◽  
N2o Production ◽  
Average Value ◽  
And Control

A benchmark simulation model, which includes a wastewater treatment plant (WWTP)-wide model and a rising main sewer model, is proposed for testing mitigation strategies to reduce the system's greenhouse gas (GHG) emissions. The sewer model was run to predict methane emissions, and its output was used as the WWTP model input. An activated sludge model for GHG (ASMG) was used to describe nitrous oxide (N2O) generation and release in activated sludge process. N2O production through both heterotrophic and autotrophic pathways was included. Other GHG emissions were estimated using empirical relationships. Different scenarios were evaluated comparing GHG emissions, effluent quality and energy consumption. Aeration control played a clear role in N2O emissions, through concentrations and distributions of dissolved oxygen (DO) along the length of the bioreactor. The average value of N2O emission under dynamic influent cannot be simulated by a steady-state model subjected to a similar influent quality, stressing the importance of dynamic simulation and control. As the GHG models have yet to be validated, these results carry a degree of uncertainty; however, they fulfilled the objective of this study, i.e. to demonstrate the potential of a dynamic system-wide modelling and benchmarking approach for balancing water quality, operational costs and GHG emissions.

scholarly journals Eco-Friendly Yield and Greenhouse Gas Emissions as Affected by Fertilization Type in a Tropical Smallholder Rice System, Ghana

2020 ◽  
Vol 12 (24) ◽  
pp. 10239
Author(s):  
Kofi Konadu Boateng ◽  
George Yaw Obeng ◽  
Ebenezer Mensah
Keyword(s):  
Greenhouse Gas ◽  
Greenhouse Gas Emission ◽  
Ghg Emissions ◽  
Poultry Manure ◽  
N2o Emissions ◽  
N2o Flux ◽  
Chromatography Method ◽  
Forest Zone ◽  
Rice Season ◽  
And Control

Data on greenhouse gas emission levels associated with fertilization applied in smallholder paddy rice farms in Ghana are scanty. The current study investigated fertilization types to determine their eco-friendliness on yield, Global Warming Potential (GWP) and Greenhouse Gas Intensity (GHGI) in a major rice season in the forest zone of Ghana. In total, five treatments were studied viz Farmer Practice (BAU); Biochar + Farmer Practice (BAU + BIO); Poultry Manure + Farmer Practice (BAU + M); Biochar + Poultry Manure + Farmer Practice (BAU + BIO + M); and Control (CT). Fluxes of methane (CH4) and nitrous oxide (N2O) were measured using a static chamber-gas chromatography method. N2O emissions at the end of the growing season were significantly different across treatments. BAU + BIO + M had highest N2O flux mean of 0.38 kgNha−1day−1 (±0.18). BAU + M had the second highest N2O flux of 0.27 kgNha−1day−1 (±0.08), but was not significantly different from BAU at p > 0.05. BAU+BIO recorded 0.20 kgNha−1day−1 (±0.12), lower and significantly different from BAU, BAU + M and BAU + BIO + M. CH4 emissions across treatments were not significantly different. However, highest CH4 flux was recorded in BAU+BIO at 4.76 kgCH4ha−1day−1 (±4.87). GWP based on seasonal cumulative GHG emissions among treatments ranged from 5099.16 (±6878.43) to 20894.58 (±19645.04) for CH4 and 756.28 (±763.44) to 27201.54 (±9223.51) kgCO2eqha−1Season−1 for N2O. The treatment with significantly higher yield and low emissions was BAU + M with a GHGI of 4.38 (±1.90) kgCO2eqkg−1.

Ecological and physiological implications of nitrogen oxide reduction pathways on greenhouse gas emissions in agroecosystems

2019 ◽  
Vol 95 (6) ◽  
Author(s):  
Sukhwan Yoon ◽  
Bongkeun Song ◽  
Rebecca L Phillips ◽  
Jin Chang ◽  
Min Joon Song
Keyword(s):  
Reductase Activity ◽  
Ghg Emissions ◽  
Mitigation Strategies ◽  
N2o Emissions ◽  
Oxide Reduction ◽  
N Budget ◽  
Ghg Mitigation ◽  
N Losses ◽  
N2o Production ◽  
N2o Reductase

ABSTRACT Microbial reductive pathways of nitrogen (N) oxides are highly relevant to net emissions of greenhouse gases (GHG) from agroecosystems. Several biotic and abiotic N-oxide reductive pathways influence the N budget and net GHG production in soil. This review summarizes the recent findings of N-oxide reduction pathways and their implications to GHG emissions in agroecosystems and proposes several mitigation strategies. Denitrification is the primary N-oxide reductive pathway that results in direct N2O emissions and fixed N losses, which add to the net carbon footprint. We highlight how dissimilatory nitrate reduction to ammonium (DNRA), an alternative N-oxide reduction pathway, may be used to reduce N2O production and N losses via denitrification. Implications of nosZ abundance and diversity and expressed N2O reductase activity to soil N2O emissions are reviewed with focus on the role of the N2O-reducers as an important N2O sink. Non-prokaryotic N2O sources, e.g. fungal denitrification, codenitrification and chemodenitrification, are also summarized to emphasize their potential significance as modulators of soil N2O emissions. Through the extensive review of these recent scientific advancements, this study posits opportunities for GHG mitigation through manipulation of microbial N-oxide reductive pathways in soil.

scholarly journals Potensi Bahan Alami dalam Menekan Produksi CH4 dan N2O dari Tanah Sawah

2021 ◽  
Vol 26 (4) ◽  
pp. 499-510
Author(s):  
Helena Lina Susilawati ◽  
Anicetus Wihardjaka ◽  
Nurhasan Nurhasan ◽  
Prihasto Setyanto
Keyword(s):  
Greenhouse Gas ◽  
Paddy Soil ◽  
Cocos Nucifera ◽  
Ghg Emissions ◽  
Nitrogen Efficiency ◽  
N2o Emissions ◽  
Nitrification Inhibitors ◽  
Ageratum Conyzoides ◽  
N2o Production ◽  
Ch4 Production

Low nitrogen efficiency is one of the sources of greenhouse gas (GHG) emissions from rice fields. Methane (CH4) and nitrous oxide (N2O) emissions could be controlled by nitrification inhibitors (NI). However, NI that has been commercialized is expensive. Therefore, some natural materials should be developed as NI that is low cost, easy to use, low N2O and CH4, and eco-friendly. The objective of this study was to observe the effect of natural NI on the production potential of CH4 and N2O from paddy soil. The experiment in the laboratory was arranged in a factorial design (2 × 7 × 3 replication). The first factor was soil types (inceptisols and vertisols), and the second factor was natural NI (control, Cocos nucifera, Camellia sinensis, Coffea robusta, Curcuma domestica, Ageratum conyzoides). The results showed that the average CH4 production from the natural NI in the inceptisols and vertisols ranged 0,014-1,710 mg CH4 g soil-1 and 0,002-0,337 mg CH4 g soil-1, respectively. Application of natural NI reduced 32-69% CH4 production compare to control. Redox potential affected CH4 production. The chemical compound of the natural NI affected CH4 production in the soil. The application of coffee waste, coconut husk, tea waste, and Ageratum conyzoides reduced 60,71; 54,61; 64,83 dan 64,16% of N2O production in Inceptisols compare to control, respectively. Application of natural NI could contribute to save the environment because it decreased GHG production in paddy soil.   Keywords: greenhouse gas, inceptisols, incubation experiment, natural nitrification inhibitors, vertisols

System Identification and Control of the Activated Sludge Process by Use of a Statistical Model

1989 ◽  
Vol 21 (10-11) ◽  
pp. 1161-1172 ◽  
Author(s):  
M. Hiraoka ◽  
K. Tsumura
Keyword(s):  
Control System ◽  
System Identification ◽  
Statistical Model ◽  
Activated Sludge ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Ar Model ◽  
Diurnal Changes ◽  
Activated Sludge Process ◽  
And Control

The authors have been developing a hierarchical control system for the activated sludge process which consists of an upper level system controlling long-term seasonal variations, a control system of intermediate level aiming at optimization of the process and a control system of lower level controlling diurnal changes or hourly fluctuations. The control system using the multi-variable statistical model is one of the most appropriate control systems based on the modern control theory, for applying the lower level control of the activated sludge process. This paper introduces our efforts for developing the reliable data acquisition system, the control experiments applying the AR-model, one of the statistical models which were conducted at a pilot plant and present studies on the system identification and control at a field sewage treatment plant.

scholarly journals Greenhouse gas emissions profiles of neighbourhoods in Durban, South Africa – an initial investigation

2017 ◽  
Vol 30 (1) ◽  
pp. 191-214 ◽  
Author(s):  
Meryl Jagarnath ◽  
Tirusha Thambiran
Keyword(s):  
Greenhouse Gas ◽  
Ghg Emissions ◽  
Mitigation Strategies ◽  
Low Carbon ◽  
Economic Activities ◽  
Emissions Inventory ◽  
High Emission ◽  
Development Goals ◽  
Reduce Emissions ◽  
The City

Because current emissions accounting approaches focus on an entire city, cities are often considered to be large emitters of greenhouse gas (GHG) emissions, with no attention to the variation within them. This makes it more difficult to identify climate change mitigation strategies that can simultaneously reduce emissions and address place-specific development challenges. In response to this gap, a bottom-up emissions inventory study was undertaken to identify high emission zones and development goals for the Durban metropolitan area (eThekwini Municipality). The study is the first attempt at creating a spatially disaggregated emissions inventory for key sectors in Durban. The results indicate that particular groups and economic activities are responsible for more emissions, and socio-spatial development and emission inequalities are found both within the city and within the high emission zone. This is valuable information for the municipality in tailoring mitigation efforts to reduce emissions and address development gaps for low-carbon spatial planning whilst contributing to objectives for social justice.

Biosolids odor reduction by solids inventory management in the secondary activated sludge treatment system

2009 ◽  
Vol 59 (2) ◽  
pp. 241-247 ◽  
Author(s):  
K. Sekyiamah ◽  
H. Kim
Keyword(s):  
Activated Sludge ◽  
Inventory Management ◽  
Process Parameters ◽  
Treatment Plant ◽  
Treatment System ◽  
Sludge Treatment ◽  
System A ◽  
Treatment Processes ◽  
Dominant Process ◽  
And Control

A wastewater treatment plant consists of unit processes designed to achieve specific waste reduction goals. Offensive odors associated with these treatment processes are a constant source of public complaints. The purpose of this study was to statistically determine the process parameters that influence the formation of volatile sulfur compounds (VSCs) in the secondary treatment system. A statistical model was developed to relate the process parameters to the formation of VSCs in this system. The model established that F/M ratio, sludge blanket depth and SSV60 were the dominant process parameters that influenced the formation of VSCs in the secondary sedimentation basin. This model provides a useful tool for plant engineers to predict and control the VSC formation in a secondary activated sludge treatment system.

Perspectives on greenhouse gas emission estimates based on Australian wastewater treatment plant operating data

2013 ◽  
Vol 69 (3) ◽  
pp. 451-463 ◽  
Author(s):  
D. W. de Haas ◽  
C. Pepperell ◽  
J. Foley
Keyword(s):  
Wastewater Treatment ◽  
Steady State ◽  
Greenhouse Gas ◽  
Greenhouse Gas Emission ◽  
Electrical Power ◽  
Research Work ◽  
Treatment Plant ◽  
Emission Factors ◽  
N2o Emissions ◽  
Operating Data

Primary operating data were collected from forty-six wastewater treatment plants (WWTPs) located across three states within Australia. The size range of plants was indicatively from 500 to 900,000 person equivalents. Direct and indirect greenhouse gas emissions were calculated using a mass balance approach and default emission factors, based on Australia's National Greenhouse Energy Reporting (NGER) scheme and IPCC guidelines. A Monte Carlo-type combined uncertainty analysis was applied to the some of the key emission factors in order to study sensitivity. The results suggest that Scope 2 (indirect emissions due to electrical power purchased from the grid) dominate the emissions profile for most of the plants (indicatively half to three quarters of the average estimated total emissions). This is only offset for the relatively small number of plants (in this study) that have significant on-site power generation from biogas, or where the water utility purchases grid electricity generated from renewable sources. For plants with anaerobic digestion, inventory data issues around theoretical biogas generation, capture and measurement were sometimes encountered that can skew reportable emissions using the NGER methodology. Typically, nitrous oxide (N2O) emissions dominated the Scope 1 (direct) emissions. However, N2O still only accounted for approximately 10 to 37% of total emissions. This conservative estimate is based on the ‘default’ NGER steady-state emission factor, which amounts to 1% of nitrogen removed through biological nitrification-denitrification processing in the plant (or indicatively 0.7 to 0.8% of plant influent total nitrogen). Current research suggests that true N2O emissions may be much lower and certainly not steady-state. The results of this study help to place in context research work that is focused on direct emissions from WWTPs (including N2O, methane and carbon dioxide of non-biogenic origin). For example, whereas non-biogenic CO2 contributions are relatively minor, it appears that opportunities to reduce indirect emissions as a result of modest savings in power consumption are at least in the same order as those from reducing N2O emissions. To avoid potentially high reportable emissions under NGER guidelines, particularly for methane, the onus is placed on WWTP managers to ensure that accurate plant monitoring operating records are kept.

scholarly journals Quantifying the Effects of Biochar Application on Greenhouse Gas Emissions from Agricultural Soils: A Global Meta-Analysis

2020 ◽  
Vol 12 (8) ◽  
pp. 3436 ◽  
Author(s):  
Qi Zhang ◽  
Jing Xiao ◽  
Jianhui Xue ◽  
Lang Zhang
Keyword(s):  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Crop Yield ◽  
Radiative Forcing ◽  
Specific Activity ◽  
C:N Ratio ◽  
Ghg Emissions ◽  
N2o Emissions ◽  
Response Ratio ◽  
Gas Emissions

Agricultural disturbance has significantly boosted soil greenhouse gas (GHG) emissions such as methane (CH4), carbon dioxide (CO2), and nitrous oxide (N2O). Biochar application is a potential option for regulating soil GHG emissions. However, the effects of biochar application on soil GHG emissions are variable among different environmental conditions. In this study, a dataset based on 129 published papers was used to quantify the effect sizes of biochar application on soil GHG emissions. Overall, biochar application significantly increased soil CH4 and CO2 emissions by an average of 15% and 16% but decreased soil N2O emissions by an average of 38%. The response ratio of biochar applications on soil GHG emissions was significantly different under various management strategies, biochar characteristics, and soil properties. The relative influence of biochar characteristics differed among soil GHG emissions, with the overall contribution of biochar characteristics to soil GHG emissions ranging from 29% (N2O) to 71% (CO2). Soil pH, the biochar C:N ratio, and the biochar application rate were the most influential variables on soil CH4, CO2, and N2O emissions, respectively. With biochar application, global warming potential (impact of the emission of different greenhouse gases on their radiative forcing by agricultural practices) and the intensity of greenhouse gas emissions (emission rate of a given pollutant relative to the intensity of a specific activity) significantly decreased, and crop yield greatly increased, with an average response ratio of 23%, 41%, and 21%, respectively. Our findings provide a scientific basis for reducing soil GHG emissions and increasing crop yield through biochar application.

scholarly journals Estimation of greenhouse gas (GHG) emissions from natural lagoon wastewater treatment plant: Case of Ain Taoujdate-Morocco

2020 ◽  
Vol 150 ◽  
pp. 01012
Author(s):  
Yassine Bahi ◽  
Ahmed Akhssas ◽  
Mohamed Khamar ◽  
Lahcen Bahi ◽  
Hanane Souidi
Keyword(s):  
Wastewater Treatment ◽  
Greenhouse Gas ◽  
Wastewater Treatment Plant ◽  
Wastewater Treatment Plants ◽  
Ghg Emissions ◽  
Treatment Plant ◽  
Empirical Method ◽  
Monthly Basis ◽  
Total Contribution ◽  
Simple Modeling

The process of removing organic components from wastewater as BOD5 through wastewater treatment plants has been proven to be a significant source of greenhouse gas emissions, mainly methane CH4, carbon dioxide CO2 and nitrous oxide N2O. The reduction of these emissions has attracted more interest given their major contribution to global warming. This study was able to identify and estimate the amount of methane and CO2 emissions on a monthly basis by a simple modeling approach and an empirical method (IPCC) for N2O emissions, in the case of Ain-Taoujdate wastewater treatment plant, throughout the years 2013, 2018 and 2019. The results showed that anaerobic ponds were the main source of on-site emissions with 66% of total contribution and 33% for facultative ponds, followed by the energy consumption of the pumping station as off-site GHG emissions.

scholarly journals A new look at an old concept: using <sup>15</sup>N<sub>2</sub>O isotopomers to understand the relationship between soil moisture and N<sub>2</sub>O production pathways

SOIL ◽  
2019 ◽  
Vol 5 (2) ◽  
pp. 265-274 ◽  
Author(s):  
Katelyn A. Congreves ◽  
Trang Phan ◽  
Richard E. Farrell
Keyword(s):  
Soil Moisture ◽  
Mitigation Strategies ◽  
Soil Conditions ◽  
Site Preference ◽  
N2o Emissions ◽  
Spectroscopic Techniques ◽  
N2o Production ◽  
Nitrification And Denitrification ◽  
The Relationship ◽  
Source Partitioning

Abstract. Understanding the production pathways of potent greenhouse gases, such as nitrous oxide (N2O), is essential for accurate flux prediction and for developing effective adaptation and mitigation strategies in response to climate change. Yet there remain surprising gaps in our understanding and precise quantification of the underlying production pathways – such as the relationship between soil moisture and N2O production pathways. A powerful, but arguably underutilized, approach for quantifying the relative contribution of nitrification and denitrification to N2O production involves determining 15N2O isotopomers and 15N site preference (SP) via spectroscopic techniques. Using one such technique, we conducted a short-term incubation where N2O production and 15N2O isotopomers were measured 24 h after soil moisture treatments of 40 % to 105 % water-filled pore space (WFPS) were established for each of three soils that differed in nutrient levels, organic matter, and texture. Relatively low N2O fluxes and high SP values indicted nitrification during dry soil conditions, whereas at higher soil moisture, peak N2O emissions coincided with a sharp decline in SP, indicating denitrification. This pattern supports the classic N2O production curves from nitrification and denitrification as inferred by earlier research; however, our isotopomer data enabled the quantification of source partitioning for either pathway. At soil moisture levels < 53 % WFPS, the fraction of N2O attributed to nitrification (FN) predominated but thereafter decreased rapidly with increasing soil moisture (x), according to FN=3.19-0.041x, until a WFPS of 78 % was reached. Simultaneously, from WFPS of 53 % to 78 %, the fraction of N2O that was attributed to denitrification (FD) was modelled as FD=-2.19+0.041x; at moisture levels of > 78 %, denitrification completely dominated. Clearly, the soil moisture level during transition is a key regulator of N2O production pathways. The presented equations may be helpful for other researchers in estimating N2O source partitioning when soil moisture falls within the transition from nitrification to denitrification.

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