加强水表质量管理

简要介绍了水表存在的质量问题并提出了解决方法。

浅谈加强水表的质量管理

水表质量的优劣和准确与否直接关系到国家、企业和广大人民群众的切身利益。因此，应加强其质量管理。

浅谈如何确保水表计量准确

水表是计量用户使用水量的仪器，是用户交纳水费的依据。城市供水需要使用大量水表，故水表计量准确与否直接关系到供水公司的营业利润，也是我们进行降低管网水量漏失率工作的重要环节。如何把好水表计量精度这一关，首先必须清楚保证水表准确计量的一些条件和因素：

Fuzzy Synthetic Evaluation of Water Quality of Naoli River Using Parameter Correlation Analysis

In order to improve the effectiveness of Fuzzy Synthetic Evaluation (FSE) models, a Parameter Correlation Analysis (PCA) was introduced into the FSE and a case study was carried out in the Naoli River in the Sanjiang Plain, Northeast China. The basic principle of the PCA is that the pairs of parameters which are highly correlated and linear with each other would contribute the same information to an assessment and one of them should be eliminated. The method of the PCA is that a correlation relationship among candidate parameters is examined before the FSE. If there is an apparent nonlinear or curvilinear relationship between two parameters, then both will be retained; if the correlation is significant (p<0.01), and the scatter plot suggests a linear relationship, then one of them will be deleted. However, which one will be deleted? For solving this problem, a sensitivity test was conducted and the higher sensitivity parameters remained. The results indicate that the original data should be preprocessed through the PCA for redundancy and variability. The study shows that introducing the PCA into the FSE can simplify the FSE calculation process greatly, while the results have not been changed much.

Development of a New Index for Integrating Landscape Patterns with Ecological Processes at Watershed Scale

Understanding the relationship between landscape pattems and ecological processes has been a central yet challenging research theme in landscape ecology. Over the past decades, many landscape metrics have been proposed but few directly incorporated ecological processes. In this paper, we developed a landscape index, namely, location-weighted landscape index （LWLI） to highlight the role of landscape type in ecological processes, such as nutrient losses and soil erosion. Within the framework of the Lorenz curve theory, we develop this index by integrating land- scape pattern and point-based measurements at a watershed scale. The index can be used to characterize the contribution of landscape pattern to ecological processes （e.g. nutrient losses） with respect to a specific monitoring point in a watershed. Through a case study on nutrient losses in an agricultural area in northeastern China, we found that nutrient losses tended to be higher for a watershed with a higher LWLI value, and vice versa. It implied that LWLI can be used to evaluate the potential risk of nutrient losses or soil erosion by comparing their values across watersheds. In addition, this index can be extended to characterize ecological processes, such as the effect of landscape pattern on wildlife inhabitation and urban heat island effect. Finally, we discuss several problems that should be paid attention to when applying this index to a heterogeneous landscape site.

Anthropogenic Impact on Surface Water Quality in Taihu Lake Region,China

Taihu Lake region is one of the most industrialized areas in China, and the surface water is progressively susceptible to anthropogenic pollution. The physicochemical parameters of surface water quality were determined at 20 sampling sites in Taihu Lake region, China in spring, summer, autumn, and winter seasons of 2005-2006 to assess the effect of human activities on the surface water quality. Principal component analysis (PCA) and cluster analysis (CA) were used to identify characteristics of the water quality in the studied water bodies. PCA extracted the first three principal components (PCs), explaining 80.84% of the total variance of the raw data. Especially, PC1 (38.91%) was associated with NH 4 -N, total N, soluble reactive phosphorus, and total P. PC2 (22.70%) was characterized by NO 3 -N and temperature. PC3 (19.23%) was mainly associated with pH and dissolved organic carbon. CA showed that streams were influenced by urban residential subsistence and livestock farming contributed significantly to PC1 throughout the year. The streams influenced by farmland runoff contributed most to PC2 in spring and winter compared with other streams. PC3 was affected mainly by aquiculture in spring, rural residential subsistence in summer, and livestock farming in fall and winter seasons. Further analyses showed that farmlands contributed significantly to nitrogen pollution of Taihu Lake, while urban residential subsistence and livestock farming also polluted water quality of Taihu Lake in rainy season. The results would be helpful for the authorities to take sound actions for an effective management of water quality in Taihu Lake region.

Spatial distribution and environmental characterization of sediment-associated metals from middle-downstream of Xiangjiang River,southern China

The contamination and environmental risk assessment of the toxic elements in sediments from the middle-downstream (Zhuzhou-Changsha section) of the Xiangjiang River in Hunan Province of China were studied. The results show that As, Cd, Pb and Zn are major contaminants in sediments, and average concentrations of these elements significantly exceed both the Control Standards for Pollutants in Sludge of China (GB4284-84) for agricultural use in acidic soils and the effect range median (ERM) values. The average concentrations of As, Cd and Pb in the river water slightly exceed the limit of Surface Water Environment Quality Standard (GB3838-2002). The concentrations of As and Cr in depth profiles extensively change, but slight changes are observed in Pb and Zn. Cd and Zn in most sediment samples can easily enter the food-chain and bring possible ecotoxicological risk to organisms living in sediments according to the risk assessment code.

A Novel Surface Aeration Configuration for Improving Gas-Liquid Mass Transfer

A novel surface aeration configuration featured with aself-rotating and floating baffle (SRFB) and a Rushton disk turbine(DT) with a perforated disk has been developed. The SRFB, consistedof 12 fan blades twisted By an angle of 30 deg to the horizontalplane, is incorporated onto the impeller shaft to improve gasentrainment, bubble Breakup, mixing in a φ 154 mm agitated vessel.This new configuration is compared to the conventional DT surfaceAeration experimentally. The results suggest that the criticalimpeller speed for onset of gas entrainment is lower for The newconfiguration and it demands greater power consumption. Moreover, theSRFB system produces 30/100-168/100 Higher volumetric mass transfercoefficient per unit power input than that obtained in theconventional DT surface Aerator under the same operation conditions.

Evaluation and Trend Analysis of Surface Water Quality in Zhengzhou in 1998-2008

Water pollution is one of the major environmental prob- lems, especially in urban areas. Due to rapid urban expansion and industrialization, water pollution in Zhengzhou City, the capital of Henan Province in central China has become a serious problem for its development. In this study, the surface water quality was evalu- ated using Nemerow Comprehensive Pollution Index （NCPI）, and the change trend was calculated using methods of Mann-Kendall test and Sen＇s slope estimator, based on the monitoring data from 1998 to 2008. The results show that the NCP1 ranged from 3 to 50 in 70% of the monitoring cases, implying that most rivers were seriously polluted. However, this serious polltuon is expected to be gradually improved, as the concentration of water pollutants and NCPI declined significantly in most rivers. Water pollution in reservoirs was much lower than rivers, and the NCPI in the three monitored reservoirs was lower than 3 in most years, and shows a downward trend. Although the surface water quality was gradually improved, great efforts are still needed to enhance the protection and improvement of surface water environment.

Environmental Effects of Water Quality of Melendiz Stream and Mamasin Dam Site in Aksaray City in the Central Anatolia of Turkey

The main purpose of this study was to determine the changes in the water quality of Melendiz and Karasu streams, which recharge the Mamasin dam, and to evaluate its environmental impacts on the dam site that provides drinking water and irrigation demand in Aksaray city in the Central Anatolia of Turkey. The field researches were focused on estimating the main sources of contamination, determining and evaluating the changes in the water quality due to the direct wastewater discharges into the Melendiz and Karasu rivers, which recharge the Mamasin dam sites. During the study, water samples were collected from Melendiz and Karasu stream and Mamasin dam, and then, the physical and chemical analyses of water samples were conducted. The relevant in-situ and laboratory analyses were carried out during the dry and wet seasons. The results of the analyses showed that in term of the surface water quality criteria in terms of NO3-N value of both rivers and dam waters, the water quality is always considered as the 1st class in Melendiz stream, the 2nd class in Karasu stream and the 3rd class in Mamasin dam lake. Whereas, in terms of NO4-N values of both rivers and dam waters, the water quality is always considered as the 1st class in Melendiz stream, the 2nd-3rd class in Karasu stream. The total organic carbon （TOC） range for Karasu river is usually from 20 mg/L to 40 mg/L. The high value of organic matter in the Karasu stream can be explained by the availability of intensive green wetlands around this water resource. Finally, the Ministry of Forest and Water Authority give some suggestions for estimating protection zones of Melendiz stream and Mamasin basin＇s area, such as using the results of environmental tracers to investigate the agricultural contamination, including more sophisticated applications of multiple-tracer analyses to evaluate the travel time of contaminants and estimate the boundary of protection zones.

Characterization of Bovine and Ovine WPC Obtained by Different Membrane Configuration Processes

The objective of this stud）, was to valorize bovine and ovine cheese whey resulting from small and medium cheese manufacture plants, by producing liquid and dr）＂ whey protein concentrates （LWPC and WPC）. The flexibility implemented by batch ultrafiltration （UF） and diafiltration （DF） allowed for the production and ovine WPC with 61 -87% （dry basis）. Diatiltration, performed in of liquid bovine WPC with 43-66% protein contents （dry basis） sequential dilution mode （DFsdm） did not improve significantly the composition of WPC liquid products comparing to the results achieved by conventional UF. However, using DF in volume reduction mode （DFvrm） protein content was increased more than 20% comparing to conventional UF. Ovine products showed higher protein levels （62-84% dry basis） what makes their manufacture attractive. Protein profiles varied with the whey origin and with the concentration process. Using batch DFvrm was possible to obtain richer protein products free of low MW compounds.

Analysis of Surface and Ground Water Exchange in Two Different Watersheds

Water regime of Albanian rivers is a Mediterranean typical one. During the wet period, it flows 85%-90% of the annual flow and the dry period represents only 10%-15% of the annual amount. In this paper the water regime of the Semani and Vjosa River is analyzed. These are two rivers with total different hydro-geological characteristics. Vjosa river watershed is mainly composed of massif calcareous rocks that are streaky and karstifled. A totally different view is in the other river, in Seman where the impermeable rocks dominate. Even the distribution of the precipitation is quite different. In the Vjosa River the amount of the precipitation varies from 1,500 mm to 2,500 mm per year and in Semani River only 1,100 mm per year. The flow in the wet period is mainly a result of the precipitation and the minimum discharge occurs during the dry period representing the base flow that is the contribution from the groundwater. In this point of view the flow in the dry period is also an indicator of the underground water resource. During the dry period the watershed gives what it received and what has cumulated during the wet period. This is more evident in the case of a karstic watershed. The recession curves were analysed for all the hydrometric stations in both river basins and the parameters of these curves are evaluated. These results are analyzed and compared between the two different watersheds reflecting the differences on water exchange of surface and ground water. Finally, an assessment of groundwater resources in both hydro geological basins is worked out.