Search results for "Warming"

Greenhouse gases from membrane bioreactors: a pilot plant case study

2015

In this study the N2O emitted from the aerobic and anoxic tank of a Sequential Batch (SB) Membrane Bioreactor (MBR) pilot plant has been investigated. The SB-MBR pilot plant was fed with a mixture of synthetic and real wastewater. The influence of salinity on N2O concentration was analyzed by gradually increasing the salinity by addition of salt to concentrations ranging from 0 to 10 gNaCl L-1. The results demonstrated that the N2O concentration of the gaseous samples was strongly influenced by the salinity in the range of 0.25 ppm to 3.4 ppm salinity. This result was explained by lower autotrophic kinetics due to the biomass lysis. Dissolved oxygen concentration and salinity were found to …

Quantifying sensitivity and uncertainty analysis of a new mathematical model for the evaluation of greenhouse gas emissions from membrane bioreactors

2015

Abstract A new mathematical model able to quantify greenhouse gas (GHG) emissions in terms of carbon dioxide (CO 2 ) and nitrous oxide (N 2 O) for a Membrane Bioreactor (MBR) is presented. The proposed mathematical model is of the Activated Sludge Model (ASM) family and takes into account simultaneously both biological and physical processes (e.g., membrane fouling). An analysis of the key factors and sources of uncertainty influencing GHG emissions is also presented. Specifically, the standardized regression coefficient, the Extended-FAST and a Monte Carlo based method are employed for assessing model factors which influence three performance indicators: effluent quality index, operational…

Towards a conceptual mathematical tool linking physical and biological processes for a reduction of ghg emissions from an mb-mbr plant

2016

The current study explores the influence of the air flow rate on greenhouse gas (GHG) emissions (direct and indirect), the operational costs (OCs), the effluent quality index (EQI) and effluent fines (EF). An University Cape Town (UCT) moving bed (MB) membrane bioreactor (MBR) pilot plant has been considered as case study where the influence of the air flow rate on the biological and physical processes has been analyzed. Constitutive relationships between the air flow rate and some performance indicators (i.e., EQI, OCs, direct and indirect GHG emissions) have been identified. Results showed that the EQI increases at low flow rate likely due to the dissolved oxygen (DO) limitation in the bi…

Outdoor Mean Radiant Temperature Estimation: Is the Black-Globe Thermometer Method a Feasible Course of Action?

2018

Urban planning has become one of the crucial action in order to address and mitigate the effect and the consequences of the global warming and it also entails different sectors of the urban context. The survey and control of the outdoor climatic conditions are among the involved sectors and mean radiant temperature is amid the most analyzed parameters. The aim of the paper is to investigate the effective suitability of one of the most used method in the assessment of the mean radiant temperature, namely the globe-thermometer method, in outdoor urban environment, singling out possible shortcomings and actual efficacy. Specifically, data obtained by measurement campaigns performed by means of…

An integrated building energy simulation early—Design tool for future heating and cooling demand assessment

2022

Climate change and its effects are becoming clear on a global scale either from the perspective of global warming and the increase in the rate of occurrence of weather events of extreme magnitude. This has impacts also for sure on the standard building performance analysis approach, since the buildings designed today are supposed to withstand for the following decades climate impacts that may be different than those they were designed for. The paper proposes a simple, easy to use and freely available building simulation utility which performs morphing of existing weather data files and, by connecting to the Energy Plus simulation routine, allows to perform future climate building simulation…

The emission saving related to the use of renewable energy sources: The case study of solar thermal collectors

2003

The employment of renewable energy sources can represent a useful way to reduce air emissions released by conventional ones. In this paper we describe the results of a Life Cycle Analysis performed upon one of the most world-wide diffused renewable technologies: the solar thermal collectors for warm sanitary water. Two domestic solar plants have been investigated: mono-familiar plant with a passive flat collector and a large solar plant with forced fluid circulation. The first step has been the evaluation of direct and indirect emissions related to the production and use of plants. The main emissions have been categorised in three of the most important indicators (Global Warming Potential, …

Life Cycle Assessment of solar heating and cooling systems: the tool “ELISA”

2018

Solar heating and cooling (SHC) systems play an important role in the achievement of energy and climate European goals. The benefits of these technologies should be evaluated taking into account their lifecycle energy and environmental impacts, calculated by applying the Life Cycle Assessment (LCA) methodology. The development of a complete LCA can be difficult and time-consuming particularly for no-LCA experts, discouraging them in the inclusion of the lifecycle perspective in their assessments. To overcome this limit, the paper presents “ELISA - Environmental Lifecycle Impacts of Solar Air-conditioning systems”, a user-friendly simplified tool for estimating the lifecycle energy and envir…

Analysis of the effects of climate change on the energy and environmental performance of a building with and without onsite generation from renewable…

2020

Climate Change is a priority, due to the large variety of implications and importance that it may cause in the next decades. In this context, the building sector is a significant contributor to greenhouse gas emissions. For this reason, buildings should be designed in such a way that they are responsible for fewer GHG emissions. In this context, the paper analyses the potential impact of climate change on the energy performances of buildings, with and without onsite generation from renewable energy, using a prototype building located in Messina (Italy) as case study. The analysis is based on Intergovernmental Panel on Climate Change RCP scenarios and the results confirm the already known ov…

2018

Ever since the beginning of international climate conservation politics there has been variation across nations in political traditions in debating the climate issue. Political decision-makers have interpreted the scientific findings on global warming with different emphases, thereby giving rise to variation in views on preferred national or international solutions. These tensions first became evident before and during the Earth Summit of the United Nations in 1992 in Rio de Janeiro, when the United Nations Climate Change Convention was prepared and eventually signed. This article discusses the historical background of international climate conservation politics and illustrates the tensions…

Nano- to Global-Scale Uncertainties in Terrestrial Enhanced Weathering.

2022

Enhanced weathering (EW) is one of the most promising negative emissions technologies urgently needed to limit global warming to at least below 2 °C, a goal recently reaffirmed at the UN Global Climate Change conference (i.e., COP26). EW relies on the accelerated dissolution of crushed silicate rocks applied to soils and is considered a sustainable solution requiring limited technology. While EW has a high theoretical potential of sequestering CO2, research is still needed to provide accurate estimates of carbon (C) sequestration when applying different silicate materials across distinct climates and major soil types in combination with a variety of plants. Here we elaborate on fundamental …