In Taiwan, the continuously increasing levels of rice imports are likely to result in surplus paddy fields. Hence, the surplus paddy fields may be developed into wetlands to increase ground water recharge, provide appropriate environments for wildlife, and most importantly, store flood water. This study developed a hydrological model incorporating the distributed rainfall‐runoff model based on the kinematics wave approach and the distributed tank model for simulation, respectively, in mountainous and flat areas. The hydrological model was found to simulate the rainfall‐runoff behavior well in the study area. Furthermore, a decision method based on the genetic algorithm concepts was proposed to give policy makers the optimal location and area size of paddy fields to construct wetlands for flood mitigation. 相似文献
The main purpose of industrial ecology is to evaluate and minimize impacts from economic activities of human society. Tourism as one economic activity, results in a full range of environmental impacts, but few applications of industrial ecology to tourism management have previously been discussed. Life cycle assessment (LCA) is used in this research to explore environmental impacts of island tourism, and then the environmental loads per tourist per trip can be found. Penghu Island in Taiwan is taken as an example to examine this new approach. Various environmental loads in transportation, accommodation, and recreation activity sector are all inventoried and calculated here. In summary, per tourist per trip uses 1606 MJ of energy, 607 L of water, and emits 109,034 g of CO2, 2660 g of CO, 597 g of HC, 70 g of NOx. In addition, per tourist per trip also discharges 416 L of wastewater, 83.1 g of BOD, and 1.95 g of solid waste. In terms of energy use, the transportation consumes the largest energy (67%); in particular, the airplane sector. Moreover, per Penghu tourist results in more environmental loads than local people; for example, the amount of solid waste discharge per tourist is 1.95 kg per day, while that of per local people is 1.18 kg. Finally, the advantages and limitations of such LCA approach are also discussed. 相似文献
This study investigated the thermal degradation energy (activation energy, Ea) for nitrocellulose (NC) with low nitrogen content of 11.71 mass%, so-called NC3, by using two different kinds of thermal analysis instruments: thermogravimetric analyzer (TGA) and differential scanning calorimetry (DSC). A comparison of Ea for various nitrogen content NC samples at two scanning rates (5 and 10 °C min?1) tested by TGA and DSC is also discussed in this paper. Meanwhile, our aim was to analyze the anti-degradation of Ea for NC with high nitrogen content, as so-called NC1. Thermal stability for NC1 with diphenylamine (DPA) was tested via DSC with 10 DPA concentrations in weights of 0, 0.25, 0.50, 0.75, 1.0, 1.25, 1.50, 1.75, 2.0, and 3.0 mass%. Experimental results indicated that Ea of NC3s was 319.91 kJ mol?1. Moreover, that while dosing DPA into NC1 the best recipe could be employed to avoid any violent NC1 runaway and also can be used to distinguish the differences of thermal decomposition Ea between NC with different nitrogen contents. This study established a fast and efficient procedure for thermal decomposition properties of NC, and could be applied as an intrinsically safer design during relevant operations. 相似文献
Biopower can diversify energy supply and improve energy resiliency. Increases in biopower production from sustainable biomass can provide many economic and environmental benefits. For example, increasing biogas production through anaerobic digestion of food waste would increase the use of renewable fuels throughout California and add to its renewables portfolio. Although a biopower project will produce renewable energy, the process of producing bioenergy should harmonize with the goal of protecting public health. Meeting air emission requirements is paramount to the successful implementation of any biopower project. A case study was conducted by collecting field data from a wastewater treatment plant that employs anaerobic codigestion of fats, oils, and grease (FOG), food waste, and wastewater sludge, and also uses an internal combustion (IC) engine to generate biopower using the biogas. This research project generated scientific information on (a) quality and quantity of biogas from anaerobic codigestion of food waste and municipal wastewater sludge, (b) levels of contaminants in raw biogas that may affect beneficial uses of the biogas, (c) removal of the contaminants by the biogas conditioning systems, (d) emissions of NOx, SO2, CO, CO2, and methane, and (e) types and levels of air toxics present in the exhausts of the IC engine fueled by the biogas. The information is valuable to those who consider similar operations (i.e., co-digestion of food waste with municipal wastewater sludge and power generation using the produced biogas) and to support rulemaking decisions with regards to air quality issues for such applications.
Implications: Full-scale operation of anaerobic codigestion of food waste with municipal sludge is viable, but it is still new. There is a lack of readily available scientific information on the quality of raw biogas, as well as on potential emissions from power generation using this biogas. This research developed scientific information with regard to quality and quantity of biogas from anaerobic co-digestion of food waste and municipal wastewater sludge, as well as impacts on air quality from biopower generation using this biogas. The need and performance of conditioning/pretreatment systems for biopower generation were also assessed. 相似文献
Daily and hourly average data from nine air-quality monitoring stations distributed across central Taiwan, which include ten items (i.e., PM10, PM2.5, wind direction, wind speed, temperature, relative humidity, SO2, NO2, NO, and CO), were collected from 2005 to 2009. Four episode types: long-range transport with dust storms (DS), long-range transport with frontal pollution (FP), river dust (RD), and stagnant weather (SW), and one mixed type of episode were identified. Of these four episode types, the SW was the dominant type, averaging about 70 %. The mean ratio of PM2.5/PM10 was the lowest during the RD episodes (0.42), while the mean ratio of PM2.5/PM10 was the highest during the SW episodes (0.64). Fine aerosol (PM2.5) and coarse aerosol (PM10–2.5) samples were collected by high-volume samplers for chemical composition analysis, from only three stations (Douliou, Lunbei, and Siansi) during the days of SW, RD, DS, and FP. The concentrations of PM2.5 and three ionic species (NH4+, NO3?, and SO42?) all showed significant differences among the four episode types. The highest levels of NO3? (12.1 μg/m3) and SO42? (20.5 μg/m3) were found during the SW and FP episodes, respectively. A comparison on the spatial similarity of aerosol compositions among the episodes and/or non-episodes (control) was characterized by the coefficient of divergence (CD). The results showed higher CD values in PM10–2.5 than in PM2.5, and the CD values between RD episodes and the other three episodes were higher than those between two types of episode for the other three episodes. The ratios of SOR (sulfur oxidation ratio), SO42?/EC (elemental carbon), NOR (nitrogen oxidation ratio), and NO3?/EC showed that sulfate formation was most rapid during the FP, while nitrate formation was most rapid during the SW. 相似文献
A computation scheme, which involves multi-step computation of the decoupled mass-balance equations in water quality models, was proposed by Park and Kuo (1996. Water Res. 30, 2255–2264). Using a simple hypothetical model, they explained the concept and demonstrated the accuracy and computational efficiency of the multi-step scheme. This paper describes the concept and the implementation of the multi-step computation scheme in a more generalized format for both intratidal and intertidal estuarine water quality models. The scheme is applied to a prototype estuary using a laterally-integrated two-dimensional intratidal model. The computational efficiency of the scheme is demonstrated by comparing the model results using the multi-step scheme with those using the traditional single-step explicit numerical solution of the kinetic processes. 相似文献
The present study tested the extraction efficiency and quantification reproducibility of anhydrosugars in a series of NIST SRMs using two extraction protocols and isotopically-labeled (d7-levoglucosan) vs. chemically analogous (sedoheptulosan) surrogates. In both instances, levoglucosan concentrations in the different versions of the Washington, D.C. urban dust standard (SRM 1649, 1649a, 1649b, and RM 8785) were similar. The present test also showed that levoglucosan concentrations were not affected by long-term shelf storage of dry material. Variability of analyses were similar for both surrogates and averaged <5%. Surrogate recoveries were shown to average 103 ± 7% and 97 ± 7% for d7-levoglucosan and sedoheptulosan, respectively. The choice of solvent was shown to affect recoveries the most (but not variability). Levoglucosan concentrations were either seriously underestimated or overestimated with ethyl acetate extraction when d7-levoglucosan or sedoheptulosan was used as surrogate, respectively. These results point to the need to use some fraction of polar solvent (i.e. methanol) in the solvent mixture. Anhydrosugar concentrations in the urban dust from the Czech Republic (candidate SRMs 2786 and 2787) were characterized by 3- to 7-fold higher anhydrosugar concentrations than those observed in the Washington, D.C. urban dust. The internal anhydrosugar signatures (i.e. levoglucosan/mannosan ratio: L/M) confirm the predominance of biomass combustion sources in both SRM series with mixed inputs from hardwood and softwood combustion in the Washington, D.C. urban dust and a predominantly softwood source in the Prague urban dust. The uniform distribution of anhydrosugars, across the particle size distribution of both SRM series, confirms earlier studies that low temperature charred materials contribute significant inputs to atmospheric ultrafine particles with long atmospheric residence time and transport ranges. 相似文献