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31.
Larry D. Qiu 《The Canadian journal of economics》2004,37(4):1061-1083
Abstract. This paper is concerned with the sustainability of free‐trade agreements (FTA). FTA sustainability is influenced by governments' valuations of political contributions, discount factors, the lobbying position of the specific‐interest groups in the intra‐industry trade sectors, and the sectoral coverage of the FTA. I find that (i) under certain conditions, the FTA under protectionist lobbying could be more sustainable than the FTA under no political pressure; (ii) the lobby‐supported FTA is more sustainable than the lobby‐opposed FTA and the FTA under no political pressure; and (iii) multisector trade enhances FTA sustainability. JEL Classification: F12, F13, F15. 相似文献
32.
Fermentative hydrogen production in a system using anaerobic digester sludge without heat treatment as a biomass source. 总被引:3,自引:0,他引:3
Hydrogen produced from anaerobic fermentation of organic matter is a sustainable energy source. Anaerobic hydrogen-producing systems have been typically seeded with heat-treated inocula to eliminate hydrogen-consuming methanogens. This can be both energy- and economically-intensive. In this work, operational parameters were modified to determine if operating a reactor at low pH (5.5) and low SRT (10 hours) would result in a hydrogen-producing system free of methanogens using anaerobic digester sludge with no heat treatment as an inoculum. Initially, the reactor exhibited a hydrogen productivity of approximately 7.9% when fed glucose. After purging was begun with 10% CO2/90% N2, the hydrogen productivity increased to > 20% for the first day. Hydrogenotrophic methanogens then established themselves in the reactor, reducing the hydrogen productivity in the second non-purged phase by 80%. The operational controls examined were not sufficient to eliminate hydrogen-consuming methanogens for longer than approximately one week, and thus further methods must be developed. 相似文献
33.
This paper first examines the rapid growth and changing composition of manufactured exports in Indonesia and Thailand, highlighting the rapid growth of office and computer machinery and electric machinery, somewhat slower growth of non-electric and transportation machinery, as well as the low growth of previously large exports of textiles apparel. Second, the important contributions of foreign multinational enterprises (MNEs) to export growth in the machinery industries, particularly in electric, office, and computing machinery, are documented. Third, the paper describes trade policies in all these industries in some detail, emphasizing how low protection was a key facilitator of rapid export growth in the MNEs that dominated the electric, office, and computing machinery industry, while high protection reduced incentives to export among MNEs in the transportation machinery industry. 相似文献
34.
O Baeder-Bederski M Dürr M Borneff-Lipp P Kuschk R Netter G Daeschlein P Mosig R A Müller 《Water science and technology》2005,51(9):205-212
Different types of constructed wetlands in a pilot-plant system were fed with identical municipal waste water to compare the sanitisation process in two-stage systems. With combinations of a vertical and a horizontal flow filter an E. coli reduction of 5 log10 with an E. coli influent concentration of 10(7) MPN/100 ml was achieved. Using different filter materials in each stage the total performance of the two-stage system was independent from the sequence of these materials. However, using coarser filter material in the first stage makes the filter less prone to clogging and is thus the preferential option with regard to operational reliability. 相似文献
35.
Lessons learnt from 15 years of ICA in anaerobic digesters. 总被引:1,自引:0,他引:1
Anaerobic digestion plants are highly efficient wastewater treatment processes with inherent energy production. Despite these advantages, many industries are still reluctant to use them because of their instability confronted with changes in operating conditions. There is therefore great potential for application of instrumentation, control and automation (ICA) in the field of anaerobic digestion. This paper will discuss the requirements (in terms of on-line sensors needed, modelling efforts and mathematical complexity) but also the advantages and drawbacks of different control strategies that have been applied to AD high rate processes over the last 15 years. 相似文献
36.
M A M Maqueda Sergio A Martinez D Narváez Miriam G Rodriguez Ricardo Aguilar Victor M Herrero 《Water science and technology》2006,53(11):135-142
The Mexican petrochemical industry, Morelos S.A. de C.V., is one of the biggest and more important petroleum industries in Mexico and Latin America. It has an activated sludge system to treat its wastewater flow, which is approximately 7,000 m3/d. The wastewater contains volatile organic carbon substances classified as toxics. The old surface aeration system was changed for fine bubble diffusers; however, one major drawback of the new aeration system is that the temperature in the bioreactor has increased due to the compression of the air, which at the compressor exit reaches 85 degrees C. This effect results in the temperature in the bioreactor attaining 32 degrees C during the fall, whereas in the spring and summer, the bioreactor temperature reaches higher values than 40 degrees C. The high temperatures reduce the microorganism activity and cause a higher volatilisation rate of volatile compounds, among other effects, which affect the performance of the biological treatment. This work was performed to obtain a better modelling of the wastewater treatment from the petrochemical industry. The model describes the effect of the temperature on the performance of the biological treatment. The model was obtained from tests that were carried out in laboratory reactors with 14 L capacity, which were operated at different temperatures (from 30 to 45 degrees C), with the same wastewater and conditions as the actual system. 相似文献
37.
J Alemany J Comas C Turon M D Balaguer M Poch M A Puig J Bou 《Water science and technology》2005,51(10):179-186
The identification of adequate wastewater treatment for small communities is a complex problem since it demands a combination of data from different sources, such as aspects of the community and landscape, the receiving environment and the available wastewater treatment technologies. The Catalan Water Agency (Agència Catalana de l'Aigua) considered using an EDSS (Environmental Decision Support System) as a tool to help water managers select the most adequate treatment for the urban wastewater of nearly 3,500 small communities in Catalonia (Spain). From that moment, EDSS was applied to all the river basins in Catalonia. In this paper the authors present the results obtained for the 76 small communities located in one of these river basins: the Fluvia River Basin. The characteristics of the community used in the reasoning process of the EDSS, the list of selected wastewater treatment alternatives, the technical environmental justification for the selected treatments and the reasons for discarding, favouring or disadvantaging them are presented. Finally, some results for the Fluvia River Basin are compared with those obtained in other Catalan river basins with different characteristics in order to evaluate which are the significant features in identifying adequate wastewater treatments. 相似文献
38.
S H Yoon J H Collins D Musale S Sundararajan S P Tsai G A Hallsby J F Kong J Koppes P Cachia 《Water science and technology》2005,51(6-7):151-157
A newly developed membrane performance enhancer (MPE) was used to prevent membrane fouling in a membrane bioreactor (MBR) process. It transpired that 1,000 mg/l of MPE reduced polysaccharide levels from 41 mg/I to 21 mg/I on average under the experimental condition. Repeated experiments also confirmed that 50-1,000 mg/l of MPE could reduce membrane fouling significantly and increase the intervals between membrane cleanings. Depending on MPE dosages and experimental conditions, trans-membrane pressure (TMP) increase was suppressed for 20-30 days, while baseline TMP surged within a few days. In addition, MPE allowed MBR operation even at 50,000 mg/l of total solid and reduced permeate COD. However, no evidence of toxicity for sludge was found from respiratory works. 相似文献
39.
The biochemical composition can be seen as a good indicator of both the biodegradability and the methane potential of a given waste. The work presented here is an attempt to elaborate a typology of wastes and to compare it to the anaerobic degradation characteristics. The first data indicate that there is a link between the ligno-cellulosic content of the waste and the biodegradability. When dealing with application to anaerobic digestion processes, having a tool to predict the ability of the waste to be degraded could be of the greatest interest for preventing failures, estimating biogas production, methane content, or for the management of co-digestion processes. 相似文献
40.
O Bernard B Chachuat A Hélias B Le Dantec B Sialve J-P Steyer L Lardon P Neveu S Lambert J Gallop M Dixon P Ratini A Quintabà S Frattesi J M Lema E Roca G Ruiz J Rodriguez A Franco P Vanrolleghem U Zaher D J W De Pauw K De Neve K Lievens D Dochaine O Schoefs H Fibrianto R Farina V Alcaraz Gonzalez V Gonzalez Alvarez P Lemaire J A Martinez F Esandi O Duclaud J F Lavigne 《Water science and technology》2005,52(1-2):457-464
The TELEMAC project brings new methodologies from the Information and Science Technologies field to the world of water treatment. TELEMAC offers an advanced remote management system which adapts to most of the anaerobic wastewater treatment plants that do not benefit from a local expert in wastewater treatment. The TELEMAC system takes advantage of new sensors to better monitor the process dynamics and to run automatic controllers that stabilise the treatment plant, meet the depollution requirements and provide a biogas quality suitable for cogeneration. If the automatic system detects a failure which cannot be solved automatically or locally by a technician, then an expert from the TELEMAC Control Centre is contacted via the internet and manages the problem. 相似文献