Investigation of drinking water bacterial community through high-throughput sequencing

<正>Delivery of safe and pathogen-free drinking water is crucial to public health.However,there exist challenges to the maintenance of the sterility of drinking water throughout the drinking water distribution systems(DWDS).Microbial growth in DWDS,such as growth of opportunistic pathogenic microorganisms,can lead to severe health problems in consumers(Berry et al.,2006;Brettar and Hofle,2006;Lu et al.,2014;Zhang et al.,2015).     

Effects of O3/Cl2 disinfection on corrosion and opportunistic pathogens growth in drinking water distribution systems

The effects of O_3/Cl_2 disinfection on corrosion and the growth of opportunistic pathogens in drinking water distribution systems were studied using annular reactors(ARs).The corrosion process and most probable number(MPN) analysis indicated that the higher content of iron-oxidizing bacteria and iron-reducing bacteria in biofilms of the AR treated with O_3/Cl_2 induced higher Fe_3O_4 formation in corrosion scales.These corrosion scales became more stable than the ones that formed in the AR treated with Cl_2 alone.O_3/Cl_2 disinfection inhibited corrosion and iron release efficiently by changing the content of corrosion-related bacteria.Moreover,ozone disinfection inactivated or damaged the opportunistic pathogens due to its strong oxidizing properties.The damaged bacteria resulting from initial ozone treatment were inactivated by the subsequent chlorine disinfection.Compared with the AR treated with Cl_2 alone,the opportunistic pathogens M.avium and L.pneumophila were not detectable in effluents of the AR treated with O_3/Cl_2,and decreased to(4.60 ± 0.14) and(3.09 ± 0.12) log10(gene copies/g corrosion scales) in biofilms,respectively.The amoeba counts were also lower in the AR treated with O_3/Cl_2.Therefore,O_3/C_l2 disinfection can effectively control opportunistic pathogens in effluents and biofilms of an AR used as a model for a drinking water distribution system.     

An inexact optimization approach for river water-quality management

A previously developed fuzzy waste load allocation model (FWLAM) for a river system is extended to address uncertainty involved in fixing the membership functions for the fuzzy goals of the pollution control agency (PCA) and the dischargers using the concept of grey systems. The model provides flexibility for the PCA and the dischargers to specify their goals independently, as the parameters for membership functions are considered as interval grey numbers instead of deterministic real numbers. An inexact or a grey fuzzy optimization model is developed in a multiobjective framework, to maximize the width of the interval valued fractional removal levels for providing latitude in decision-making and to minimize the width of the goal fulfillment level for reducing the system uncertainty. The concept of an acceptability index for order relation between two partially or fully overlapping intervals is used to get a deterministic equivalent of the grey fuzzy optimization model developed. The improvement of the optimal solutions over a previously developed grey fuzzy waste load allocation model (GFWLAM) is shown through an application to a hypothetical river system. The fuzzy multiobjective optimization and fuzzy goal programming techniques are used to solve the deterministic equivalent of the GFWLAM.     

Factors affecting private forest landowner interest in ecosystem management: linking spatial and survey data

Many factors influence forest landowner management decisions. This study examines landowner decisions regarding participation in ecosystem management activities, such as a landscape corridor cutting across their private lands. Landscape corridors are recognized worldwide as an important tool in biodiversity conservation. For ecosystem management activities to occur in areas dominated by a multitude of small private forest landholdings, landowner participation and cooperation is necessary. Data from a survey of landowners combined with an analysis of their land's spatial attributes is used to assess their interest in ecosystem management. Results suggest that spatial attributes are not good predictors of an owner's interest in ecosystem management. Other factors such as attitudes and opinions about the environment are more effective in explaining landowner interest. The results have implications for any land manager using GIS data and implementing ecosystem management activities on private forestland.     

STATISTICAL LOW FLOW ESTIMATION USING GIS ANALYSIS IN HUMID MONTANE REGIONS IN PUERTO RICO1

ABSTRACT: Statistical analysis of watershed parameters derived using a Geographical Information system (GIS) was done to develop equations for estimating the 7d–10yr, 30d–10yr, and 7d–2yr low flow for watersheds in humid montane regions of Puerto Rico. Digital elevation models and land use, geology, soils, and stream network coverages were used to evaluate 21 geomorphic, 10 stream channel, 9 relief, 7 geology, 4 climate, and 2 soil parameters for each watershed. To assess which parameters should be used for further investigation, a correlation analysis was used to determine the independence and collinearity among these parameters and their relationship with low flows. Multiple regression analyses using the selected parameters were then performed to develop the statistical models of low flows. The final models were selected in the basis of the Mallow Cp statistic, the adjusted R², the Press statistic, the degree of collinearity, and an analysis of the residuals. In the final models, drainage density, the ratio of length of tributaries to the length of the main channel, the percent of drainage area with northeast aspect, and the average weighted slope of the drainage were the most significant parameters. The final models had adjusted standard errors of 58.7 percent, 59.2 percent, and 48.6 percent for the 7d–10yr, 30d–10yr, and 7d–2yr low flows respectively. For comparison, the best model based on watershed parameters that can be easily measured without a GIS had an adjusted standard error of 82.8 percent.     

Development of information intensive agrichemical management services in wisconsin

This paper examines opportunities to improve the environmental and economic performance of cropping systems through intensified application of information in agrichemical management. Through intensified application of information, both net farm income and environmental quality may increase through more closely matching the specific needs of the crop with the type, timing, and volume of chemical inputs used in crop production. This study examines the current status and future prospect of agrichemical dealers offering information intensive agrichemical management services to producers. Agrichemical dealers are the focus of this study because: (1) farmers are perceived as ill-prepared to substantially upgrade the sophistication of their agrichemical management without off-farm support, and (2) dealers enjoy a close relationship with farmers, which potentially could be expanded to include a variety of information-based services. A mail survey was conducted of all agrichemical suppliers/applications in Wisconsin. The response rate was 76% (172 of 225). Substantial numbers of services were found to be offered by many dealers. The majority of these services were related to traditional yield-enhancement function. Services that have a greater potential to mitigate the negative environmental impacts of inefficient agrichemical use and have higher on-farm data requirements were found to be less widely offered by dealers. Analysis of constraints to further development of information-intensive services indicates that dealers offering significant numbers of services are concerned with constraints external to the dealership, while dealers offering relatively few services perceive internal constraints as most limiting. This relationship indicates that efforts to accelerate dealerships' development of information-intensive agrichemical management services should focus on specific constraints operating on targeted dealerships.     

SELECTION OF WASTE DISPOSAL SITES USING GIS1

ABSTRACT: Geographic Information Systems (GIS) technology is used to identify candidate sites for a solid waste disposal facility in the Gölbasi region of Turkey that has suffered from the negative impact of a current but poorly-located open-dump site on the environment. The municipality of Gölbasi has noticed its deleterious effect on the environment, and has thus decided to dismiss this open-dump site and search for new landfill sites. In this study, the procedure followed under a GIS framework rejects the unacceptable sites considering environmental factors exclusively, other than economic and political issues, contained in the form of multiple layers of attribute information to select the candidate sites for landfilling wastes through an overlay analysis performed by GIS software, ARC/INFO V 7.1. For the spatial data requirements of GIS, a number of thematic map layers (ground water, wetlands and swamp areas, surface water, roads, topographic contours, ecological features, settlements, erosion susceptibility zones, and soil type) are prepared in digital form. In this application, GIS is considered as a screening tool in a site selection process to narrow the number of candidate sites, subsequently leading to one or more sites for detailed investigation. Preliminary ranking for a group of potential sites is done on the basis of simple calculations coupled with on-site field studies.     

县级生态农业建设规划的编制

本文运用生态经济学、系统工程学和规划论的观点,对如何编制县级生态农业建设规划进行了探讨。提出编制规划的基本思路和应遵循的主要原则,并从现状评价、潜力分析、规划目标、规划方案、重点项目、效益预测和主要措施等方面对规划应包括的主要内容和具体要求进行了系统的阐述。     

Assessing landscape dynamics in a protected area

This article describes an approach to assessing spatial and temporal land-use and land-cover changes in and adjacent to protected areas and to the measurement of landscape stability within a protected area. Methods employed include aerial photographic interpretation and GIS technology. Odum's four-compartment ecosystem model provides the conceptual framework for assessing landscape stability. The study area is a selected sample of the Upper San Pedro National Riparian Conservation Area in the high desert grassland of southeastern Arizona. Significant changes were observed in the landscape matrix and riparian ecosystem. However, when these changes were assessed in the context of Odum's model, the change was nonsignificant. Implications of the approach and potential applications in protected area management are discussed.     

Conventional and alternative technologies for the treatment of infectious waste

 The limited scientific information about infectious waste, and the heightened public awareness of this special component of the waste stream, have contributed to the implementation or strengthening of the regulations in this area. This paper proposes a general working definition of infectious waste, and describes the systems used to limit its potential occupational and public health impacts. Although incineration and autoclaving are the most widely used methods of treating infectious waste, the introduction of more stringent air-quality standards for incinerators, and the inherent limitations to the application of autoclaves, have created a demand for other methods of processing this segment of the solid and liquid waste streams. These alternative technologies use one or more of the following methods: (1) heating the waste to a minimum of 90–95°C; (2) exposing the waste to suitable chemicals; (3) subjecting the waste to heated chemicals; (4) irradiating the infectious waste with ionizing sources. The advantages and disadvantages of each of these alternative forms of treatment are discussed in this paper. Received: April 22, 2002 / Accepted: October 14, 2002