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A regional framework for establishing recovery criteria 总被引:6,自引:0,他引:6
Robert M. Hughes Thomas R. Whittier Christina M. Rohm David P. Larsen 《Environmental management》1990,14(5):673-683
Effective assessments of aquatic ecosystem recovery require ecologically sound endpoints against which progress can be measured.
Site-by-site assessments of end points and potential recovery trajectories are impractical for water resource agencies. Because
of the natural variation among ecosystems, applying a single set of criteria nationwide is not appropriate either. This article
demonstrates the use of a regional framework for stratifying natural variation and for determining realistic biological criteria.
A map of ecoregions, drawn from landscape characteristics, formed the framework for three statewide case studies and three
separate studies at the river basin scale. Statewide studies of Arkansas, Ohio, and Oregon, USA, streams demonstrated patterns
in fish assemblages corresponding to ecoregions. The river basin study in Oregon revealed a distinct change at the ecoregion
boundary; those in Ohio and Montana demonstrated the value of regional reference sites for assessing recovery. Ecoregions
can be used to facilitate the application of ecological theory and to set recovery criteria for various regions of states
or of the country. Such a framework provides an important alternative between site-specific and national approaches for assessing
recovery rates and conditions. 相似文献
524.
Budget changes, whether positive or negative, in water quality management agencies often mean a change in resources available for water quality monitoring. Many state agencies are currently facing monitoring budget cuts and, as a result, are reevaluating their monitoring programs. Such evaluations make use of a number of information sources, not the least of which are monitoring activities in other states. This article reports results of a survey of all fifty state water quality monitoring programs. Twenty questions were asked in the general areas of fixed-station monitoring, special studies, and biological monitoring. Each state was contacted by telephone at least twice during the survey. Fixed-station monitoring is conducted by 48 of 50 states. An average of 75 stations per state are sampled, generally on a monthly basis. There is a large variation in the way data are analyzed by the states; water quality indices and plots of concentration or loading over time are the most common methods. All but three states conduct special studies, but only seven repeat the studies on a regular basis. Special studies are generally problem specific as opposed to basin oriented. Biological monitoring is performed by 33 states; however, this is an area in which budget cuts are having a noticeable impact. In some cases, biological monitoring is being completely eliminated or suspended. Macroinvertebrate sampling is performed quarterly to biannualiy by 50% of the states; 75% of the states that sample macroinvertebrates do so annually. Periphyton sampling is performed by 33% of the states. Over 50% of the states are in the process of revising, or have revised, their monitoring program during the past five years. However, only four states had a detailed rationale and operating procedure for the entire monitoring system. Results of the survey are, therefore, averages of existing monitoring programs. Average results do not necessarily represent ideal situations, but do give an indication of how states are coping with their monitoring responsibilities. 相似文献
525.
毛细渗透法测定固体表面能 总被引:1,自引:0,他引:1
根据粒度对固体表面能的影响,选用了毛细渗透法测定固体表面能.详细介绍了毛细渗透法的原理和实验操作步骤.最后得出结论,毛细渗透法测定固体颗粒的表面能,是一种较好的测试方法. 相似文献
526.
文章概述了含砷废水的产生及其处理方法,重点介绍了国内外研究报道较少的活性污泥法,以引起人们对这一有效除砷方法的重视。通过总结活性污泥法除砷的研究进展,探讨了活性污泥除砷的机理和影响因素,并提出今后要从活性污泥法除砷的机理、除砷工艺、及含砷废渣处理三方面开展研究,以促进该方法的应用。 相似文献
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优势微生物强化水解—多级接触氧化工艺处理屠宰废水 总被引:2,自引:0,他引:2
结合工程实例,本文对优势微生物强化水解—多级接触氧化处理屠宰废水工艺及设计体会进行了讨论。设计进水COD、BOD5、SS、NH3-N、动植物油为2300~2700mg/L、900~1300mg/L、600~800mg/L、100~120mg/L、70~90mg/L,出水为90mg/L、20mg/L、60mg/L1、0mg/L1、0 mg/L。实际运行结果表明:主要出水指标COD、BOD5、SS、NH3-N、动植物油的去除率分别可达到97.9%、98.6%、93.7%、93.4%、90.7%。该工艺具有占地少、建设成本低、运行可靠、稳定达标、剩余污泥少、运行成本低、维护简便等优点。 相似文献
530.
污水生物处理系统中内源过程的研究进展 总被引:4,自引:0,他引:4
污水生物处理系统的内源过程涉及到一系列微生物学、生态学机制和过程,因而对处理系统的各个方面都有重要影响.然而-目前对内源过程的认识还相当有限.本文首先在总结现有知识的基础上对污水生物处理系统中的内源过程作了定义,并对其区分为细胞和群落两个水平-随后,分别对内源过程中的细胞维持、解偶联、程序化细胞死亡、饥饿状态、高等微生物捕食等过程作了综述,总结了其在污水生物处理领域的研究进展.此外.文章还概述了细胞维持能量和细胞衰减速率的测定方法及其研究进展和存在的问题.本文的目的是通过综述现有的知识,推动对污水生物处理系统中内源过程研究的进一步发展. 相似文献