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121.
This study employs a parametric input distance function that incorporates both desirable and undesirable outputs to provide a more complete representation of the production technology from which environmentally sensitive productivity and efficiency measures can be generated. This framework also generates pollution abatement cost estimates that are useful for policy making. An input-based Malmquist index of productivity growth that appropriately credits the producer not only for increases in marketable or desirable outputs but also for the production of improved environmental quality through pollution abatement activities is derived from the input distance function. The method was applied to time series data from the Canadian pulp and paper industry. Our shadow price estimates indicate that the marginal cost to producers of pollution control has been rising. The main conclusion of this study is that productivity improvement, from the social viewpoint, has been stronger than conventional measures would suggest.  相似文献   
122.
水是人类赖以生存的条件之一,没有了水,人类将无法生存,世间万物也都将不复存在。因此,合理的利用水资源、治理废水、保护环境是分析工作者的责任和使命。废水的分析项目有很多,其中耗氧量是水被污染的检验指标之一,耗氧量又分为化学耗氧量和生化耗氧量(即COD与BOD5),二者之间既有区别又有联系。  相似文献   
123.
为促进干旱区湖泊健康发展,分析了博斯腾湖大湖区湖水多年溶解氧与五日生化需氧量、高锰酸盐指数、总磷、总氮和氨氮的动态特征:1991年-2014年(2009、2012除外)水体溶解氧为6.71~9.20 mg/L,最高值与最低值分别在2005年和2006年,此与2005年水位最高,而后下降的特征一致;五日生化需氧量在0.5~6.99 mg/L变幅较大,并与溶解氧同年出现最高值,且二者符合线性回归关系y=0.213x+7.053;高锰酸盐指数波动明显;总氮和总磷则较平稳;氨氮从0.01 mg/L升至最高值0.45 mg/L.高锰酸盐指数和总氮对水质影响最大.  相似文献   
124.
125.
魏星  易杨柳 《四川环境》2008,27(5):31-34
对武汉市某小型浅水人工湖泊水质进行一年的理化监测并分析,结果显示:COD、BOD5均有季节性变化的规律;气温的变化影响湖水及底泥中微生物的活性;天然降水量不同对湖水稀释程度不同;底泥的污染物释放量受温度影响;该水体可生化性差。据此,提出保护湖水的措施。  相似文献   
126.
To investigate the relationship between methane production in the sediments and pollution of the river and lake, biochemical oxygen demand (BOD) and chemical oxygen demand (COD) of the water sample, organic matter content and methane production of the sediment were measured. Experimental results indicated that BOD, COD and organic matter contents were low in Bei-tan Lake, the I-lan River and reservoirs; and methane production of these sediments ranged from 0.24 to 1.06 mg L- 1. However, BOD, COD and organic matter contents were high in the Hsin-dan River, Keelung River, drainage river of Taoyuan County, park pond and fishery pond. Methane production of these sediments was between 11.75 and 54.54 mg L-1. Sediments of drain river and fishery pond had high methane production, at 25.41 to 54.54 mg methane L. Methane production of sediments had a good correlation with BOD, COD and organic matter contents. Methane production was proportional to the increment in incubation temperature from 12 to 40C.  相似文献   
127.
从接种液种类、空白BOD5大小、接种液最佳添加范围等方面对BOD5测定进行探讨,提出以接纳工业废水的河水作为最佳接种液,雨季时以土壤浸取液更适合。探讨了接种液空白值对BOD5标液和工业废水的影响,结果表明,河水空白应控制在0.1-0.8mg/L土壤浸取液空白控制在0.01-0.10mg/L为宜。  相似文献   
128.
We introduce a generalized form of the common first-order (exponential) decay model, that has potential utility for describing contaminant declines in environmental applications, particularly when declines are a mixture of many underlying processes. The exponent on contaminant concentration is left as a free parameter allowing the order of the reaction to be determined by the data. The mixed-order model is more flexible than models with the exponent determined a priori, facilitating an improved fit to observed behavior. We demonstrate the utility of this model, and compare it to two other models, by estimating PCB concentration declines in Lake Michigan fishes.  相似文献   
129.
BOD5分析方法中计算公式存在的误差进行了分析,并提出了可消除计算误差的修正建议。  相似文献   
130.
Abstract: Selection of a biochemical oxygen demand (BOD) reaction model to incorporate into dissolved oxygen (DO) water quality models is an overlooked choice available to river water quality modelers. Data from rivers can serve in screening methods to discriminate between competing water quality models. In this study, 15 published BOD and DO datasets based on a 7 year long study of the Bormida River in Italy are used to calibrate three‐multiorder BOD models: first‐order, three‐halves order, and second‐order, which are then included in three corresponding DO models which incorporate these BOD models. The adequacy of the first‐order, three‐halves order and second‐order BOD models was evaluated by calculating the root mean square error between a model and data. A similar procedure was followed to evaluate three DO models, each of which incorporated one of the three BOD models. The first‐order BOD model most frequently fit the river data best, followed by the three‐halves order and the second‐order BOD models. The DO model incorporating a first‐order BOD model most frequently fit the data best, followed by the DO order incorporating second‐order BOD and the DO model incorporating three‐halves order BOD.  相似文献   
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