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101.
102.
为了研究不同好氧预处理方式对餐厨垃圾厌氧消化产甲烷的影响,通过建立3个模拟厌氧生物反应器,研究了传统厌氧生物反应器C1、上层好氧预处理-厌氧生物反应器C2和底部好氧预处理-厌氧生物反应器C3 3种不同操作条件下的产甲烷过程.结果表明,挥发性有机酸的累积使C1始终处于产甲烷滞后阶段;而C2、C3的好氧预处理通过加快易水解酸化组分和过量挥发性有机酸的好氧降解,有效缓解了酸性抑制,产甲烷滞后时间明显缩短至10 d内.第32天C2停止上层曝气后,在27 d内甲烷浓度达到了50%以上,同时,产甲烷速率迅速上升,并在第81天可达到峰值773 mL/(kg·d).C3在第11天停止底部曝气后,虽然经过22 d的时间甲烷浓度即上升至50%,但之后产甲烷速率经历回落阶段后再次逐渐上升,在实验结束时仅达到517 mL/(kg·d).上层曝气的好氧预处理方式所需曝气时间相对较长,但其产甲烷启动快,与底部曝气相比,其后期的甲烷化过程更稳定并可达到较高的产甲烷速率. 相似文献
103.
能源短缺和环境污染已成为中国推行全面协调可持续发展的重要制约因素,作为能源消耗的主体和环境污染的控制重点,在城市层面推动能源发展战略的转变和强化环境保护是发展的基本要求.鉴于能源与环境之间的高度关联性,在管理方面要求对能源发展和环境保护进行统筹考虑和综合管理,充分强调能源经济效率和环境制约因素在能源发展中的作用.通过制定合理的产业能效标准和排放绩效标准,为城市经济、能源和环境的可持续性发展提供科学性、系统性决策支持. 相似文献
104.
通过对大连城市环境系统的考察,设立了完整的评价指标体系,运用模糊优选理论建立模糊评价模型,对大连城市环境进行了定量研究,并结合经济和城市化情况进行了分析。研究结果表明:城市环境质量总体上是在逐年提高的,但从2002年以来发展较为平缓。经济和城市化情况有较大发展,但仍有不足之处。 相似文献
105.
为提高乳品工业废水生物处理的去污脱氮能力,以新型螺旋状纤维填料作为载体,采用多级氧化槽内不同种类微生物形成的食物链系统(food chain reactor),详细考察了不同水力停留时间COD、TN、NH+4-N、TP等的去除率及其去除机理,并对污泥减量化效果进行了初步探讨.结果表明,当进水COD为842~1 843 mg/L、TN为36.3~92.2 mg/L、NH+4-N为30.1~52.1 mg/L,HRT=6 h时,系统COD的平均去除率达到93.3%;TN和NH+4-N的去除效果显著,其平均去除率分别达到73.3%和80.7%,出水COD、TN、NH+4-N平均值分别为79.4 mg/L、9.6 mg/L、6.1 mg/L,均低于《污水综合排放标准》(GB 8978-2002)的一级标准.该系统不仅具有较高的去污脱氮效果,而且产生的剩余污泥量极少,其污泥产率的平均值为7.7%.该系统运行费用低,操作管理方便,长期运行稳定,可应用于城市污水、中高浓度有机废水(如餐厅污水、食品工业废水)等的处理. 相似文献
106.
Transaction costs in community-based resource management are incurred by households attempting to enforce property right rules over common resources similar to those inherent in private property rights. Despite their importance, transaction costs of community-based management of common pool resources (CPRs) are often not incorporated into the economic analysis of participatory resource management. This paper examines the transaction costs incurred by forest users in community forestry (CF) based on a survey of 309 households belonging to eight different forest user groups (FUGs) in the mid hills of Nepal. The analysis reveals that the average 'poor' household incurred Nepalese rupees (NRS) 1265 in transaction costs annually, while wealthier 'rich' households incurred an average of NRS 2312 per year. Although richer households bear higher proportions of such costs, transaction costs for CF management as a percentage of resource appropriation costs are higher for poorer households (26%) than those of middle-wealth (24%) or rich households (14%). There are also village differences in the level of transaction costs. The results show that transaction costs are a major component of resource management costs and vary according to socio-economic status of resource users and characteristics of the community. 相似文献
107.
Delang CO 《Environmental management》2006,37(4):470-486
This article discusses the system of classification of forest types used by the Pwo Karen in Thung Yai Naresuan Wildlife Sanctuary
in western Thailand and the role of nontimber forest products (NTFPs), focusing on wild food plants, in Karen livelihoods.
The article argues that the Pwo Karen have two methods of forest classification, closely related to their swidden farming
practices. The first is used for forest land that has been, or can be, swiddened, and classifies forest types according to
growth conditions. The second system is used for land that is not suitable for cultivation and looks at soil properties and
slope. The article estimates the relative importance of each forest type in what concerns the collection of wild food plants.
A total of 134 wild food plant species were recorded in December 2004. They account for some 80–90% of the amount of edible
plants consumed by the Pwo Karen, and have a base value of Baht 11,505 per year, comparable to the cash incomes of many households.
The article argues that the Pwo Karen reliance on NTFPs has influenced their land-use and forest management practices. However,
by restricting the length of the fallow period, the Thai government has caused ecological changes that are challenging the
ability of the Karen to remain subsistence oriented. By ignoring shifting cultivators’ dependence on such products, the involvement
of governments in forest management, especially through restrictions imposed on swidden farming practices, is likely to have
a considerable impact on the livelihood strategies of these communities. 相似文献
108.
Study of urban population attitudes towards various wastewater reuse options: Israel as a case study
This paper summarizes the findings of a survey (256 participants) conducted to determine the attitude of the Israeli urban public towards various urban water reuse options. Israel is known for its long and successful agricultural water reuse scheme, but to date no large-scale urban reuse projects have been implemented. The survey included 21 reuse options, which were clustered into three reuse categories, namely: low, medium, and high contact levels. Results show that a high proportion of the participants supported medium contact reuse options such as sidewalk landscaping (95%), domestic WC flushing (85%) and firefighting (96%). Higher contact reuse options such as domestic laundry (38%), preserved food (13%), and potable aquifer recharge (11%) found much lesser support. Less than expected support was found for low contact reuse options with 86% for field crop irrigation, 62% for aquifer recharge for agricultural irrigation, and as low as 49% for orchard irrigation. This low support is surprising, since all three options have been practiced on a large scale for over three decades in Israel without any adverse effects to the public. No correlation was found between any biographical characteristic examined (education, gender, income, marital status, having young children, and age) and support for medium contact options. For the medium contact options, the results suggest that perceived financial gain (individual and/or communal) and positive public opinion enhances support, while perceived health effects negatively affects the degree of support. Technology, trust in authorities and awareness of water and environmental issues were found to not have a significant effect on support for medium contact reuse options. Analyzing the four possible reasons for support given by participants who identified themselves as supporters of wastewater reuse revealed that the most important reason for support was "water saving", followed by "minimization of importing water from abroad". These were followed by "infrastructure cost saving" together with "environmental improvement". 相似文献
109.
Tarsitano E 《Environmental management》2006,38(5):799-809
In urban ecosystems, the ecological system has become completely unbalanced; this, in turn, has led to an increase in well-known
problems such as air pollution, ground pollution, and water pollution. This imbalance has also led to the growth and spread
of pathogens harmful to man, animals, and plants. Urban sustainability indicators, both global and local, also “indicate”
the percentage of population, but these refer only to the human population, not the animal population. Cities need good waste,
water, and air management, effective traffic planning, and good zoning of businesses, crafts, and services; over and above
these activities, cities also need for planning to take into account the existence of pets (dogs, cats, and etc.) and nonpet
animals (insects, birds, mice, etc.). Cities tend to be designed around humans and “on a human scale,” without taking into
account the fact that a huge animal population is living side by side with people. That explains why overcrowding tends to
go hand in hand with urbanization; all these populations, including humans, need to adapt to new spaces and often need to
drastically change their behavior. This is a fact that must be included when drafting sustainable city plans. The supposed
strategy is that of “integrated-participatory” control of the interactions between the environment and animals in the cities.
Strategy will focus on the development of integrated approaches and tools for environment and animal management in the context
of urban settings. This will require such specific methods as ecological balance sheets and ecoplans for the planning, management,
and control of the interrelation among environment, animal, and public health. The objective is to develop a better understanding
of urban biodiversity and of urban ecosystem functioning, in order to understand and minimize the negative impacts of human
activities on them. The research will focus on assessing and forecasting changes in urban biodiversity, structure, function,
and dynamics of urban ecosystems, with relationships among society, economy, biodiversity, and habitats. 相似文献
110.
矿物材料对餐厨垃圾厌氧消化的影响研究 总被引:16,自引:0,他引:16
在试验的基础上研究了3种矿物材料膨润土、斜发沸石、粉煤灰对富含钠离子的餐厨垃圾厌氧消化过程的影响.结果表明,在发酵温度为35℃、底物固含量(TS)为10%、添加物用量为1%(质量分数,以消化底物计)时,膨润土、沸石粉、粉煤灰对含盐餐厨垃圾的厌氧发酵消化液中的钠离子具有良好的吸附性能,吸附率分别为13.75%、10.11%、7.99%.在未使用无机矿物的情况下,当钠离子浓度为3000~4000mg·L-1时,含盐餐厨垃圾的的厌氧消化过程受到Na 离子的明显抑制.从产气量分析,3种矿物材料均能明显促进餐厨垃圾的厌氧消化过程,与空白对照试组相比,膨润土、斜发沸石、粉煤灰分别使产气量提高了131%、82%和45%.三者对甲烷气产量的促进影响强弱顺序是,膨润土>斜发沸石>粉煤灰.初步讨论了这3种矿物材料提高餐厨垃圾厌氧消化甲烷产量的作用机理. 相似文献