Environmental and Energy Assessment of Municipal Wastewater Treatment Plants in Italy and Romania: A Comparative Study

This study presents a holistic approach to evaluate energy performance and greenhouse gas (GHG) emissions from urban water supply and sanitation stages, which are important for sustainable water management and climate change mitigation. The study was conducted for Antalya city of Turkey to compare baseline and improved scenario conditions using the Energy Performance and Carbon Emissions Assessment and Monitoring (ECAM) tool. The current application of urban water and wastewater services was defined as the baseline scenario. For the improved urban water cycle, the reduction of non-revenue water, onsite sanitation prevention, increase in energy efficiency, biogas production and reuse of treated wastewater were investigated. Water supply and sanitation stages contributed to approximately 26 and 74% of total GHG emissions and 70 and 30% of energy consumption for the baseline scenario, respectively. GHG emissions were determined approximately as 52,423 tCO2eq/year for CO2 (40%), 47,029 tCO2eq/year for CH4 (35%) and 33,006 tCO2eq/year for N2O (25%) for the baseline scenario. The total GHG emissions of 132,457 tCO2eq/year and energy consumption of 136,328 MWh/year were reduced by 27.65% for GHG emissions and 16.48% for energy consumption for the improved urban water cycle. The outcomes of this research are expected to achieve sustainable cities and combat climate change.

This study presents a baseline assessment of carbon emissions in water utilities in Madaba, Jordan. The Energy Performance and Carbon Emissions Assessment and Monitoring Tool (ECAM) is applied in the present study in order to reduce indirect and direct emissions. Input data for the assessment included inter alia, population, water volumes, energy consumption, and type of wastewater treatment. The methodology focuses on the greenhouse gas (GHG) emissions and energy use that is directly associated with the utility operations covering the whole water cycle. The ECAM's Quick Assessment revealed that 89.7% of the energy is consumed in abstraction and distribution systems of water supply, whereas wastewater collection, treatment, and discharge consumed only 10.3% in Madaba. The detailed ECAM tool assessment results showed that total GHG emissions from the entire water and wastewater system in Madaba are approximately 28.122 million kg CO2/year. The water supply is the major contributor to GHG accounting for 62.4%, while 37.6% of GHG emissions result from sewage treatment, and are associated with treatment process requirements considered in this work, in addition to sludge transport from septic tanks to the wastewater treatment plant. The findings of this work can help the utility to undertake energy efficiency and GHG reduction measures.

Municipal water and wastewater services have complicated sources of greenhouse gas (GHG) emissions, and quantifying their roles is critical for tackling global environmental challenges. In this study we provide a systematic review of the state‐of‐the‐art on GHG emission characterizations of China's urban water infrastructure with the aim of shedding light on global implications for sustainable development. We started by synthesizing a framework on GHG emissions associated with water and wastewater infrastructure. Then we analyzed the different sources of GHG emissions in drinking water and wastewater treatment systems. In drinking water services, electricity consumption is the largest source of GHG emissions. A particular concern in China is the common use of secondary pumping for high‐rise buildings. Optimized pressure management with an efficient pumping system should be prioritized. In wastewater services, non‐CO2 emissions such as methane (CH4) and nitrous oxide (N2O) emissions are substantial, but vary greatly depending on regional and technological differences. Further research directions may include GHG inventory development for urban water systems at the plant level, quantifications of GHG emissions from sewer systems, emission reduction measures via water reclamation, renewable energy recovery, energy efficiency improvement, cost–benefit analyses, and characterizations of Scope 3 emissions.This article is categorized under: Engineering Water > Sustainable Engineering of Water Science of Water > Water and Environmental Change Engineering Water > Planning Water

In recent times, waste management has emerged as a significant environmental challenge, and sewage is among the major contributors due to the rapidly increasing population. Despite sewage treatment plants (STPs) being the solution for the treatment of sewage, they have been identified as sources of greenhouse gas (GHG) emissions. This study aimed to estimate the contribution of STPs to GHG emissions in the state. This was achieved by visiting the sites, filling scientifically designed questionnaires, sample collection as well as computational methods by Intergovernmental Panel on Climate Change. The assessment of direct and indirect emissions from the STPs revealed that emissions were caused by the activated sludge process, electricity consumption, transportation, and sludge storage. Electricity consumption by STPs was responsible for the highest emissions, accounting for 43% of the total emissions, equivalent to 20,823 tCO2 eq. The activated sludge process contributed 31% (14,934 tCO2 eq) of the emissions, while storage of sludge in landfills accounted for 24% (11,359 tCO2 eq). Additionally, transportation contributed 2% (1121 tCO2 eq) of the emissions. In total, the STPs in Himachal Pradesh had the potential to contribute 48,237 tCO2 eq GHG emissions annually. Thus, the study suggests process-level modifications in STPs of Himachal Pradesh to mitigate GHG emissions. This research provides insight into the GHG emissions from STPs and highlights the need for their management to reduce environmental impacts.

Urban water cycle systems(UWCS), including water treatment facilities, distribution facilities, sewers, and wastewater treatment facilities, are energy intensive and significant source of greenhouse gas (GHG) emissions, making the reduction of GHG emissions and the transition to eco-friendly energy essential. This study identifies specific GHG emission sources at each stage of the UWCS and proposes detailed methods to achieve a 40% reduction in GHG emissions, implement RE100, and attain Net Zero by employing insets and offsets. This study develops scenarios for insets and offsets based on the baseline process of the UWCS, and investigates potential pathways to reduce GHG emissions by quantifying emissions from each process. Internal insets, which are self-implemented and technical measures, are prioritized, while external offsets are applied to compensate for the remaining emissions. Internal insets include the application of anaerobic digesters and combined heat and power(CHP), improvements in energy efficiency of equipment, reduction in water pipe leakage, implementation of water footprint labeling, and installation of on-site photovoltaic system. External offsets comprise renewable energy certificates(REC), power purchase agreements(PPA), green hydrogen fuel for vehicles, natural sequestration improvement, and emission trading system. GHG emissions at each stage within the UWCS are quantified using modeling software. Based on these results, the effectiveness of insets and offsets in achieving a 40% GHG emissions reduction, Net Zero, and RE100 goal is analyzed. The baseline total GHG emissions for the UWCS are estimated at 4,732.8 tCO2eq/yr, of which 56.8% is identified as targets for internal insets, and the remaining 43.2% is reduced through external offsets. A 40% GHG reduction can be achieved through internal insets, and Net Zero can be attained by incorporating additionally applying external offsets. The total power demand of UWCS facilities and equipment is calculated as 572.8 kW. Renewable energy is generated through anaerobic digesters and CHP(116.1kW) as well as on-site PV(395.0 kW), while RE100 compliance is achieved by securing an aditional 61.7 kW through REC/PPA. Achieving Net Zero and RE100 requires prioritizing strategies for insets, offsets and efficient resource allocation. For this, the technical feasibility and self-implementation potential of reduction efforts and the external conditions for offsets, should be carefully reviewed to optimize implementation strategies. GHG reduction and renewable energy utilization in the UWCS are key priorities for addressing the climate crisis and achieving sustainable water resource management, requiring technological innovation and institutional support. The comprehensive and systematic application of GHG insets and offsets is the optimal approach to achieving these goals. Furthermore, modeling software serves as a key tool for quantifying GHG emissions and formulating concrete, viable GHG reduction strategies. In addition to the technical and institutional approaches proposed in this study, achieving Net Zero and implementing RE100 requires the integrated consideration of economic factors in the future.

Wastewater treatment plants (WWTPs) using membrane bioreactor (MBR) technology have been considered a significant source of greenhouse gas (GHG) emissions. This study chose a small-scale wastewater treatment plant using MBR technology to estimate its potential for GHG emissions. The total GHG emissions from this wastewater treatment plant ranged from 2,802 to 11,946kg CO2 -eq/month within the 4-year study period, and they were mainly attributable to electricity consumption (79.94%) followed by chemical usages (17.13%) and on-site GHG emissions (2.93%). The on-site GHG emissions varied monthly, but most of them ranged from 80 to 160kg CO2 -eq/month. The aeration tank was an important operating unit for GHG emissions. Off-site GHG emissions mainly came from carbon dioxide (CO2 ) emissions resulting from electricity consumption. The results of this study provide useful information about the potential of GHG emissions from WWTPs using MBR technology and indicate that WWTPs can be sustainably managed. PRACTITIONER POINTS: Wastewater treatment plants have been considered a source of greenhouse gas emissions. Total greenhouse gas emissions from the wastewater treatment plants using membrane bioreactor were mainly attributable to electricity consumption. On-site greenhouse gas emissions were relatively insignificant in this study.

Embodied GHG emissions of buildings – The hidden challenge for effective climate change mitigation

Different environmental and social concerns can arise due to the generation of gaseous emissions during the treatment of urban wastewater. However, there is not an extensive knowledge about which are the main potential odour and greenhouse gas (GHG) emission sources in a wastewater treatment plant (WWTP) and their variability. In this study, a multipoint characterization of the gaseous emissions generated in a full-scale municipal WWTP located in Barcelona was conducted, aiming at identifying the main odour and GHG emission sources. The WWTP under study treats an average inlet flow of 33,000 m3 d−1 using a Ludzack-Ettinger system with Membrane BioReactor (MBR) technology, and it has installed a gas caption and treatment system consisting of a biotrickling filter followed by a conventional biofilter to treat part of the off-gases produced during the wastewater treatment. For this work, gaseous emissions characterization campaigns were conducted to assess the proper performance of the gas treatment unit and to estimate the emission factors referred to odorants and GHGs for the different emission sources and to assess the proper performance of the gas treatment system. Besides, a chemical characterization of the different volatile organic compounds (VOC) present in the gaseous emissions was performed through TD-GC/MS. The main potential odour sources were the reception tank, the barscreens building and the primary settler, where odour concentrations were in the range of 1300 and 2600 ou·m−3. Moreover, GHG emissions were found during the primary treatment and in the MBR units, ranging from 2.21 to 68,217.13 mg CO2eq·m−3. Different VOCs such as aromatic hydrocarbons, alkanes and ketones were found in the gaseous emissions with a high variability among all the emission sources. The results obtained are valuable indicators that can be used to develop odour and GHG mitigation strategies in WWTPs and to estimate the environmental impact of these facilities.

Modeling greenhouse gas emissions from biological wastewater treatment process with experimental verification: A case study of paper mill

Municipal wastewater treatment plants (MWWTPs) are considered significant artificial sources of greenhouse gas (GHG) emissions, in the forms of methane (CH4) and nitrous oxide (N2O), during their normal operations. In this study, we used an emission factor method to determine the spatial and temporal distribution characteristics of GHG emissions from MWWTPs in China during the period 2005–2014; influencing factors and uncertainties were also analyzed. Our results show that total GHG emissions from Chinese MWWTPs increased from 326.54 to 1294.03 Gg CO2‐eq between 2005 and 2014, and that regional distribution was extremely variable. During this decade, the proportion of CH4 in the total GHG emissions decreased from 74.1 to 59.4% while that of N2O increased from 25.9 to 40.6%. The observed increase in N2O was probably due to the enhancement of wastewater discharge standards for nitrogen discharge, resulting in lower waterborne but higher atmospheric levels of nitrogen oxides. Our comparison of GHG emissions from wastewater discharging directly to the aquatic environment with that treated at MWWTPs in 2014 indicate that the latter disposal method resulted in an 18‐fold drop in GHG emissions. Regional economic development level and wastewater treatment capacity were the factors most closely related to GHG emissions from MWWTPs; the per‐capita protein supply was closely related to N2O emissions.

Livestock farming constitutes a significant source of greenhouse gas (GHG) emissions, presenting a challenge to the fulfilment of regional and international climate change mitigation. However, research on the mitigation of livestock emissions remains underrepresented in environmental legal scholarship. The current exploratory study aims to bridge this gap by systematically addressing law research focused on reducing GHG emissions from livestock. Given the distinct characteristics of various regional contexts, this work places a particular emphasis on the European Union (EU). Indeed, while maintaining ambitious climate change mitigation obligations, the EU records unhealthily high levels of animal food production and consumption. Furthermore, considering both its strong enforcement powers and the central role it plays as one of the main producers and consumers of animal food products worldwide, the EU is in a privileged position for conditioning global animal food systems. The article begins by outlining the scale and features of livestock’s impact on climate change. It then reviews the existing legal literature on the mitigation of livestock emissions, with a special focus on EU-specific analyses. After highlighting insights from current legal scholarship, assessing its alignment with scientific evidence, and identifying research gaps, the article proposes the development of a research agenda focused on the EU mitigation of livestock GHG emissions, informed by four preliminary observations. The observations clarify that: 1-the livestock sector has traditionally been neglected in climate change law and policy documents; 2-there is shortage of legal research on the mitigation of livestock emissions at the EU level; 3- curbing livestock related GHG emissions will have a major role to play for the EU to meet international and regional climate change mitigation obligations; 4- at the EU level, there is no possibility to decouple livestock production and consumption from GHG emissions.

Sewage treatment processes are considered an important source of greenhouse gas (GHG) emissions, particularly N2O and CH4. In rural sewage treatment processes, GHG emissions are often neglected owing to the small scale of treatment and dispersed distribution. In this study, the non-CO2 GHG emission quantity, spatiotemporal distribution characteristics, and influences factors were analyzed based on rural sewage from 2015 to 2020. Emissions from rural sewage treatment in 2020 reached 122.72 Gg (CO2-eq), comprising 69.81 Gg N2O and 52.91 Gg CH4, representing a 35.29% increase compared to 2015. There are large variations between province-level regions: more GHG was emitted from the eastern than the north-west of China. The treatment of rural domestic sewage can simultaneously purify water quality and decrease GHG emissions, and the improvement in the rate of treatment is beneficial to "carbon peak and carbon neutralization." GHG emissions from rural sewage treatment showed a positive correlation with both GDP and sewage discharge, and N2O was positively correlated with protein consumption per capita. This study would provide a theoretical basis for policy formulation, as it supplies basic data on carbon emissions for China's rural sewage treatment. SUMMARY: Rural sewage treatment (RST) plants contribute significantly to GHG emissions. N2O emission from rural sewage treatment in 2020 in China was 69.81 Gg. CH4 emission from rural sewage treatment in 2020 in China was 52.91 Gg. Large variations in GHG emissions were found between province-level regions. Domestic RST can simultaneously purify water quality and decrease GHG emissions.

Mitigating climate change and achieving stabilization of greenhouse gas atmospheric concentrations — the objective of the United Nations Framework Convention on Climate Change (UNFCCC) — will require deep reductions in global Energy-related Carbon Dioxide (CO2) emissions. G-8 leaders called for a 50% reduction in greenhouse gas (GHG) emissions before 2050 to avoid the most serious consequences of climate change. Meeting this goal requires transforming the way energy is produced, delivered, and consumed across all sectors of the economy and regions of the world. Energy efficiency offers seemingly glittering promises to all-savings for consumers and utilities, profits for shareholders, improvements in industrial productivity, enhanced international competitiveness and reduced environmental impacts. As global energy demand continues to grow, actions to increase energy efficiency will be essential. The technical opportunities are myriad and potential savings real, but consumers and utilities have so far been slow to invest in the most cost-effective, energy-efficient technologies available. The energy efficiency of buildings, electric equipment, and appliances in use falls far short of what is technically attainable. Energy analysts have attributed this efficiency gap to a variety of market, institutional and technical constraints. Electric utility energy efficiency techniques have great potential to narrow this gap and achieve significant energy savings. This paper provides some of the recent trends in energy efficiency technologies that have been successful and also used widely worldwide. They are: 1) Energy efficient motors 2) Soft starters with energy saver 3) Variable speed drives 4) Energy efficient transformers 5) Electronic ballast 6) Occupancy sensors & Energy efficient lighting controls 7) Energy efficient Lamps This paper presents Case Studies of various energy efficient techniques used in a Steel Plant resulting in considerable Electrical energy savings varying from 10–15%. Electric motors drive both core industrial processes, like presses or roll mills, and auxiliary systems, like compressed air generation, ventilation or water pumping. They are utilized throughout all industrial branches, though the main applications vary. With only some exceptions, electric motors are the main source for the provision of mechanical energy in industry. In recent years, many studies identified large energy efficiency potentials in electric motors and motor systems with many saving options showing very short payback times and high cost-effectiveness. Furthermore, almost all electricity in India is generated by rotating electrical generators, and approximately half of that generated is used to drive electrical motors. Hence, efficiency improvements with electrical machines can have a very large impact on energy consumption. The key challenges to increased efficiency in systems driven by electrical machines lie in three areas: a. To extend the application areas of variable-speed electric drives through reduction of power electronic and control costs b. Secondly, to integrate the drive and the driven load to maximize system efficiency c. Finally, to increase the efficiency of the electrical machine. Lighting is a large and rapidly growing source of energy demand and greenhouse gas emissions. At the same time the savings potential of lighting energy is high, even with the current technology, and there are new energy efficient lighting technologies coming onto the market. Currently, more than 33 billion lamps operate worldwide, consuming more than 2650 TWh of energy annually, which is approximately 19% of the global electricity consumption. The introduction of more energy efficient lighting products and procedures can at the same time provide better living and working environments and also contribute in a cost-effective manner to the global reduction of energy consumption and greenhouse gas emissions.

The article presents an assessment of the main sources of greenhouse gas emissions in the «Waste» sector in the Republic of Belarus in the context of global climate change and its impact on the environment. The relevance of this study is determined by the growing problems associated with waste management, as well as the necessity to reduce greenhouse gas emissions to achieve climate goals established by international agreements. From 1989 to 2019, the average annual temperature in the country increased by 1.3°C. Predictions from Belarusian scientists forecast a further temperature rise of 1–5°C by the end of the century. Belarus, as a party to the UN Framework Convention on Climate Change (UNFCCC), the Kyoto Protocol, and the Paris Agreement, has committed to reducing greenhouse gas emissions by 28% by 2030 compared to 1990 levels. The “Waste” sector is a significant source of greenhouse gases, related to the processes of disposal, recycling,and landfilling of large volumes of waste generated by human activities. It has been established that the main sources of greenhouse gas emissions in this sector are solid municipal waste landfills and wastewater treatment facilities. This sector accounts for 32.76% of the total national methane (CH4) emissions and 4.17% of nitrous oxide (N2O) emissions. The total volume of greenhouse gas emissions in the «Waste» sector in 2020 amounted to 5,829.72 Gg in CO2-equivalent, which constitutes 6.56% of the total emissions in the country. The results obtained highlight the importance of developing effective waste management strategies to reduce greenhouse gas emissions and minimize their impact on the climate system.

Sewage treatment processes are considered an important source of greenhouse gas (GHG) emissions, particularly N2O and CH4. In rural sewage treatment processes, GHG emissions are often neglected owing to the small scale of treatment and dispersed distribution. In this study the non-CO2 GHG emission quantity, spatiotemporal distribution characteristics, and influences factors were analyzed based on rural sewage from 2015 to 2020. Emissions from rural sewage treatment in 2020 were 122.72 Gg (CO2-eq), comprising 69.81 Gg N2O and 52.91 Gg CH4, an increase of 35.29%. There are large variations between province-level regions: more GHG was emitted from the eastern than the north-west of China. The treatment of rural domestic sewage can simultaneously purify water quality and decrease GHG emissions, and the improvement in the rate of treatment is beneficial to, ‘carbon peak and carbon neutralization’. GHG emissions from rural sewage treatment showed a positive correlation with both GDP and sewage discharge, and N2O was positively correlated with protein consumption per capita. This study would provide a theoretical basis for policy formulation, as it supplies basic data on carbon emissions for China's rural sewage treatment.