Methane (CH4) removal in the presence of ethanol vapors was performed by a stone-based bed and a hybrid packing biofilter in parallel. In the absence of ethanol, a methane removal efficiency of 55 ± 1% was obtained for both biofilters under similar CH4 inlet load (IL) of 13 ± 0.5 gCH4 m?3 h?1 and an empty bed residence time (EBRT) of 6 min. The results proved the key role of the bottom section in both biofilters for simultaneous removal of CH4 and ethanol. Ethanol vapor was completely eliminated in the bottom sections for an ethanol IL variation between 1 and 11 gethanol m?3 h?1. Ethanol absorption and accumulation in the biofilm phase as well as ethanol conversion to CO2 contributed to ethanol removal efficiency of 100%. In the presence of ethanol vapor, CO2 productions in the bottom section increased almost fourfold in both biofilters. The ethanol concentration in the leachate of the biofilter exceeding 2200 gethanol m?3leachate in both biofilters demonstrated the excess accumulation of ethanol in the biofilm phase. The biofilters responded quickly to an ethanol shock load followed by a starvation with 20% decrease of their performance. The return to normal operations in both biofilters after the transient conditions took less than 5 days. Unlike the hybrid packing biofilter, excess pressure drop (up to 1.9 cmH2O m?1) was an important concern for the stone bed biofilter. The biomass accumulation in the bottom section of the stone bed biofilter contributed to 80% of the total pressure drop. However, the 14-day starvation reduced the pressure drop to 0.25 cmH2O m?1. 相似文献
Environmental Science and Pollution Research - Construction and demolition waste (CDW) and municipal solid waste (MSW) are the waste flows mostly generated at a global level. In developing... 相似文献
The occurrence of 43 pharmaceuticals belonging to predominant therapeutic classes and their distribution in surface water, suspended solids and sediments has been investigated in the Ebro river basin in the Northeast of Spain. WWTP effluents were found to be a main source of contamination and the spatial distribution was affected by the river flow at the sampling point and corresponding dilution factor, resulting in higher concentrations and higher loads in small tributary rivers than in the Ebro river. The study showed that some compounds are preferentially found bound to suspended solids and not detected in river water. Generally, compounds with basic characteristics (pKa > 7) showed higher tendency to bind to suspended solids. The sediment samples generally presented lower concentrations than suspended solids. 相似文献
In present research work the effect of climate change over the humidex in Iran is analyzed. From this research, we can conclude that the PDIAQ index showed a special sensibility to changes in temperature and relative humidity, hence, it can be an interesting tool, may be even better than the humidex to show the expected effect of climate change in perception of air quality. Thus, it was found that the humidex expected in the future will be more elevated than that in the preceding period and, on the other hand, the PDWRC has clearly reached a lower value than in the preceding period. The same effects, other than those using the earlier indexes in a more detailed manner, were observed with the PDIAQ. This index showed a higher sensitivity to variations in temperature and relative humidity, than the humidex. Finally, the main results obtained must be considered at the time of design and during construction of future buildings, since buildings that are being constructed today will be occupied in the future years of the 2100s. 相似文献
Sustainability science is a solution-oriented discipline. Yet, there are few theory-rich discussions about how this orientation structures the efforts of sustainability science. We argue that Niklas Luhmann’s social system theory, which explains how societies communicate problems, conceptualize solutions, and identify pathways towards implementation of solutions, is valuable in explaining the general structure of sustainability science. From Luhmann, we focus on two key concepts. First, his notion of resonance offers us a way to account for how sustainability science has attended and responded to environmental risks. As a product of resonance, we reveal solution-oriented research as the strategic coordination of capacities, resources, and information. Second, Luhmann’s interests in self-organizing processes explain how sustainability science can simultaneously advance multiple innovations. The value logic that supports this multiplicity of self-organizing activities as a recognition that human and natural systems are complex coupled and mutually influencing. To give form to this theoretical framework, we offer case evidence of renewable energy policy formation in Texas. Although the state’s wealth is rooted in a fossil-fuel heritage, Texas generates more electricity from wind than any US state. It is politically antagonistic towards climate-change policy, yet the state’s reception of wind energy technology illustrates how social and environmental systems can be strategically aligned to generate solutions that address diverse needs simultaneously. This case demonstrates that isolating climate change—as politicians do as a separate and discrete problem—is incapable of achieving sustainable solutions, and resonance offers researchers a framework for conceptualizing, designing, and communicating meaningfully integrated actions. 相似文献
Rapid land-use change arising from incentives for afforestation has created tensions in rural communities previously dominated
by agricultural enterprises. This paper reports on an innovative experiment with social learning that incorporated participatory
modelling to resolve community concerns in a case study of plantation forestry in the Upper Clarence catchment of north-eastern
NSW Australia. The development of a diagnostic framework helped identify socioeconomic and environmental issues within the
community for investigation by a self-selected participatory advisory committee (PAC) representing a diversity of views. Implementation
of a social learning exercise offered empathetic and intellectual engagement among PAC members that maintained interest, built
confidence, and improved problem-solving capacity while fostering group ownership over decision making. A shared understanding
of dynamic landscape problems helped empower participants to collaboratively develop solutions for improved management and
operational practices, and cooperate to explore further options for plantation industry development under existing policy
guidelines which are presented in this paper. As a result of frank discussions between diverse stakeholders in a mutually
respectful learning environment that combined local, scientific and expert knowledge, concerns dissipated and participants
developed a more favourable view of plantation forestry activity. 相似文献
This study presents an integrated hydrologic–economic model as decision support system for groundwater use and incorporates uncertainties of climate change. The model was developed with the Vensim software (Ventana Systems) for system dynamic simulations. The software permitted the integration of economic variables along with hydrologic variables, in a unified format with the aim of evaluating the economic impacts of climate change on arid environments. To test the model, we applied it in one of the upper Tunuyán River sub-basin, located in the Mendoza Province (Argentina), where irrigation comes from groundwater. The model defines the best mix of crops and the total land use required to maximize the total river sub-basin monetary income, considering as a limit the amount of water that does not exceed the natural annual aquifer recharge. To estimate the impacts of climatic changes, four scenarios were compared: the business as usual (with the number of existing wells) in a dry year with a temperature increase of 4 °C; the business as usual in a wet year with an increase in temperature of 1.1 °C; an efficient use of wells in a dry year and a temperature increase of 4 °C and an efficient use of wells in a wet year with a temperature increase of 1.1 °C. Outputs calculated by the model were: land use per crop, total sub-basin net benefit, total sub-basin water extraction, water extraction limit depending on river discharge and total number of wells required to irrigate the entire area. Preliminary results showed that the number of existing wells exceeded the optimized number of wells required to sustainably irrigate the entire river sub-basin. Results indicated that in an average river discharge year, if wells were efficiently used, further rural development would be possible, until the limit of 350 million m3 of water extraction per year was reached (650 million m3 for a wet year and 180 million m3 for a dry year). The unified format and the low cost of the software license make the model a useful tool for Water Resources Management Institutions, particularly in developing countries. 相似文献
Participation is usually regarded as a good practice in environmental policymaking, but its effects on policy strategies are unclear. Based on literature research, surveys, and interviews with participants, the present paper assesses whether decisional participation in formulating Austria’s National Adaptation Strategy (NAS) was worth the effort. Assessed against the goals of the participation process, we find that it raised awareness for adaptation and facilitated an exchange among the participants and that it improved the content of the NAS. However, regarding the goal of enhancing the acceptance of and commitment to the NAS, we find that this has been achieved among those who participated but not among high-level policymakers who are responsible for implementing the NAS. We conclude that (decisional) participation has its benefits in formulating comprehensive policy strategies but that it is most likely not able to overhaul their well-documented weaknesses, among them weak political commitment and implementation failures.
Historical trends of PCDD/Fs and PCBs from the year 1900 have been reconstructed for the Venice Lagoon area by using a fugacity-based dynamic multimedia model. A novel approach to estimate the inputs to the system was applied. Emissions to the lagoon were estimated by studying dated sediment cores taken from salt marshes located in the lagoon area. These cores have recently proven to be a suitable tool to reconstruct the temporal trends of atmospheric deposition of POPs. According to the model, concentrations of PCBs and PCDD/Fs in air and water reflect the trends of their production and usage, peaking during the 1960s. The peaks in the sediment were delayed by 5-40 years depending on the congener. Predicted concentrations are in good agreement with experimental results. The most important input parameters, identified by a sensitivity analysis, are the degradation constants, K(ow), the Henry's law constant, vapour pressure, active sediment depth, sediment resuspension, and deposition rates, and water residence time in the lagoon. 相似文献