黄葛增压站的噪声综合治理

根据黄葛增压站周边环境状况、增压机噪声强度及频谱分析特性,结合吸音、隔音、扩容、变频、减震、阻尼等降噪原理和治理技术,提出了该站噪声最优化的治理方案。监测结果表明,黄葛增压站噪声治理后的厂界噪声达到了《工业企业厂界噪声标准》(GB12348-90)规定的三类标准要求,该治理方法切实可行。     

空冷器噪声源分析及降噪措施研究

空冷器噪声导致厂界噪声超标现象时有发生,通过现场调查、参数测量、理论分析计算等手段,判断出空冷器进气噪声、排气噪声、风机叶片旋转噪声、高速气流与风筒摩擦噪声是厂界噪声超标的关键因素。文章在此基础上制定了针对性措施,降低了厂界噪声,满足环保标准要求。     

工业企业厂界噪声测量问题探讨

针对现行GB 12348-2008在厂界噪声实际测量中存在的一些问题进行分析探讨,并提出解决的方法与建议。     

某天然气处理厂压缩机噪声分析及治理方案

苏里格气田某天然气处理厂增压站天然气压缩机在运行过程中厂界噪声超过GB 12348—2008《工业企业厂界环境噪声排放标准》2类标准,通过分析压缩机组运行时产生的噪声源特性,结合国内降噪治理技术现状,提出3种治理方案,利用声学模拟软件对治理效果进行模拟,结果表明:在室外空冷器区域设置降噪房、消音器以及压缩机房降噪升级治理后,厂界噪声可满足GB 12348—2008《工业企业厂界环境噪声排放标准》2类标准,为该处理厂噪声治理提供了参考依据。     

某气田增压站压缩机组噪声治理效果分析

针对川东地区大多数增压场站存在的厂界噪声超标问题，以某气田增压站为例，从生产设备、厂界范围入手，分析了压缩机组噪声超标点位，提出了噪声超标治理方案。经现场改造后，噪声排放满足GB 12348—2008《工业企业厂界环境噪声排放标准》二类昼间≤60 dB（A），夜间≤50 dB（A）的要求。该压缩机组 降噪治理应用有效降低了噪声水平，符合国家环保政策，为气田后期开发提供参考。     

工业建设项目竣工环境保护验收问题初探

结合工业项目竣工验收中的常见问题，就敏感点噪声的监测方法、厂界噪声监测布点、等效排气筒参数计算、监测期间生产负荷计算等问题，进行探索。     

某天然气净化厂噪声污染来源及治理

某天然气净化厂投产初期厂界夜间噪声值超过GB 12348—2008《工业企业厂界环境噪声排放标准》3类声环境功能区噪声限值的要求。为降低噪声,该天然气净化厂通过现场测试确定主要噪声源,并将声源 噪声类型、噪声值、厂区和周边地势图输入噪声控制分析软件对厂界噪声进行声场模拟,分析计算各声源点需 降噪量,再结合声源现场情况制定了针对性的治理方案。通过采取加装消声器、隔声罩、隔声墙、隔声门等降噪 措施,消减了中控室空调风机和装置区透平风机、离心风机、污水回注泵、冷却水循环泵等的噪声影响,将厂界 噪声控制在55 dB（A）以下,满足了国家标准要求。     

油田企业厂界噪声监测技术要点

针对油田企业厂界噪声监测过程中遇到的技术难点,在熟练理解GB 12348—2008《工业企业厂界环境噪声排放标准》的基础上,归纳总结了测量条件、测点位置、测点布设、背景噪声、测量记录等过程细节的技术要点,并在实际监测工作中得以应用,为管理和决策提供了科学、有效和准确的监测数据。     

石化炼制企业噪声治理探讨

文章通过对石油化工炼制企业噪声的分析,相对不同场所噪声源进行不同治理方案的探讨,就某石化公司典型装置蒸馏装置为例进行噪声源及相应的治理方案分析,选择在临厂界处建设隔声屏障,对声源进行有效的阻隔,监测结果表明:隔声屏障起到了有效的隔声降噪作用,厂界噪声达GB 12348-2008《工业企业厂界环境噪声排放标准》。     

工业企业厂界环境噪声监测中背景噪声监测及修正探讨

针对测量结果修正的相关要求，本文对新颁布的《工业企业厂界环境噪声排放标准》（GB12348-2008）和旧标准《工业企业厂界噪声测量方法》（GB／T12349-1990）在实际工作中的运用进行了比对、分析和探讨，并根据实际工作经验，提出了在背景噪声难以测量的一些特殊情况下的几种解决途径，主要提出噪声源声值与背景声值相差小于3dB（A）时的解决方案。     

PRODUCTION PROCESSES UNDER THE ICE IN LAKE ST. CLAIR: 1. IRRADIATION AND TEMPERATURE1

ABSTRACT: Data from three ice-covered stations in Lake St. Clair were collected to evaluate the effect of ice and related variables on phytoplankton production. Primary production, phytoplankton standing crop, irradiation and temperature were measured from January to April, 1973. Mean production values ranged from 0.74 mgC/m³/h at station 1 near Mitchell Bay to 3.4 mgC/m³/h in waters at stations 2 and 3 below the Thames River mouth. A similar pattern was observed in chlorophyll a concentration, the mean values ranged from 0.63 μg/1 at station 1 to 2.1 and 1.3 μg/1 at stations 2 and 3. Temperature stratification occurred at the three stations. However, the temperatures at station 1 were consistently more than a degree warmer than at the other two stations. Irradiation was low, having a mean value at the sampling depth of .075 ly/min. The data is interpreted to indicate that the ice-bound phytoplankton were adapted to the low irradiation. It is suggested that the variation observed between stations is related to the formation of a plume by the Thames River and differences in nutrient loads carried by the St. Clair and Thames Rivers.     

京杭运河(苏州段)水质时空分布特征分析

本文基于数据分析工具Excel 2007和SPSS17.0,采用多元统计方法中的聚类分析与判别分析对2008年京杭运河(苏州段)水质时空分布特征进行分析,以识别水质指标的时间与空间差异性。时间分析结果将京杭运河(苏州段)划分为与丰、平、枯水期略有差异的3个时期,其中7项显著性时间差异的水质指标为pH、NH4-N、CODMn、DO、BOD5、V-phen、cn-total。空间分析结果将研究区域分为3个污染区域;空间分析判别函数的构建表明仅pH、NH4-N、CODMn、DO、BOD55项水质指标即可反映研究区域水质的差异性。本研究结果对改善省界河流水质、缓解省际纠纷、维护社会和谐稳定具有重要意义。     

Trends in water quality in LEASEQ rivers and streams (northwestern Ohio), 1975-1995. Lake Erie Agricultural Systems for Environmental Quality

Trends in water quality in four northwest Ohio rivers over the period 1975-1995 were identified using datasets of daily concentrations containing 4500 to 6800 observations per river during the study period. Concentrations were log-transformed prior to analysis, and adjusted for flow using a locally weighted scatterplot smoother (LOWESS) fit between log(concentration) and log(flow). Seasonality was modeled using one- and two-cycle sinusoidal oscillations and monthly additive constants. Substantial decreases in total and soluble reactive phosphorus were documented at all stations. Smaller but highly significant decreases in total Kjeldahl nitrogen were documented at all stations, and significant decreases in total suspended solids were documented at three of the four stations. Nitrate did not show significant trends at the two stations draining major watersheds, and showed significant trends in opposite directions at the two stations on smaller watersheds. Comparisons using nonparametric, nonlinear trend fits (LOWESS) suggest that changes in fertilizer and manure application rates are the most important cause of trends in phosphorus and total Kjeldahl nitrogen; point sources are insufficient to account for the phosphorus trends. The conflicting trends for nitrate are enigmatic, but may reflect diverging land use in the two smaller watersheds.     

DECLINING INTENSITY OF ACID MINE DRAINAGE IN THE NORTHERN APPALACHIAN BITUMINOUS COAL FIELDS: MAJOR ALLEGHENY RIVER TRIBUTARIES1

ABSTRACT: For more than 30 years, a program of continuous monitoring of pH, acidity, alkalinity, and other parameters has been maintained on a network of large streams degraded by acid mine drainage in the northern Appalachian high sulfur coal region. Continuous records since 1952 are available at a number of stations, and at several stations, acidity records date back to 1930. Comparable analysis techniques were maintained over the period of record, assuring the long term continuity of the database. This monitoring program has captured integrated long term trends within large and complex watersheds with numerous and varied types of mine discharges. The focus of this paper is a historical trend analysis of lightly to severely acid degraded major tributaries of the Allegheny River. Over the past three decades, all of the Allegheny River drainage basin stations have demonstrated steady and substantial declines in acidity and associated increases in pH and alkalinity. The average recorded decline in total acidity at four stations monitored since the 1950s was 94 percent. Since the 1970s, acidity declined by an average of 63 percent at 10 stations. Oxidative exhaustion of pyritic minerals exposed by mining is proposed as a major factor influencing these trends.     

遥感技术在基层环境监测单位的常见应用

卫星遥感成为环境监测的新手段,基层环保部门由于受技术装备、知识储备、资金的限制,只能开展部分工作。文章介绍了常见的数据源,基层单位可开展的常见工作及取得的工作经验。期望为广大环保基层单位在现有条件下开展遥感环境监测工作提供参考。     

JUSTIFICATION FOR A REDUCTION IN THE CREST-STAGE GAGE PROGRAM IN LOUISIANA1

The crest-stage gage program in Louisiana was evaluated to determine if the data were adequate for use in developing regional flood-frequency equations and to determine if any crest-stage gage stations could be discontinued. An abundance of data at many crest-stage gage stations and a lack of data for urban areas and flat-slope areas indicated a need for a shift in the number, type, and locations of gages. Correlations and comparisons of annual peak discharges and watershed characteristics of 96 existing stations resulted in the elimination of 72 stations and the addition of one new station, reducing the total network to 25 stations that could be used for future flood-frequency analyses. The adequacy of the reduced network for development and verification of regional flood-frequency equations was tested by comparing a set of regional flood-frequency equations developed using data from the full network with a set developed using data from the reduced network. The results indicate that the crest-stage gage network can be reduced to 25 stations and still provide adequate information for future flood-frequency analyses.     

Use of Streamflow Data to Estimate Base Flow/Ground‐Water Recharge For Wisconsin1

Abstract: The average annual base flow/recharge was determined for streamflow‐gaging stations throughout Wisconsin by base‐flow separation. A map of the State was prepared that shows the average annual base flow for the period 1970‐99 for watersheds at 118 gaging stations. Trend analysis was performed on 22 of the 118 streamflow‐gaging stations that had long‐term records, unregulated flow, and provided aerial coverage of the State. The analysis found that a statistically significant increasing trend was occurring for watersheds where the primary land use was agriculture. Most gaging stations where the land cover was forest had no significant trend. A method to estimate the average annual base flow at ungaged sites was developed by multiple‐regression analysis using basin characteristics. The equation with the lowest standard error of estimate, 9.5%, has drainage area, soil infiltration and base flow factor as independent variables. To determine the average annual base flow for smaller watersheds, estimates were made at low‐flow partial‐record stations in 3 of the 12 major river basins in Wisconsin. Regression equations were developed for each of the three major river basins using basin characteristics. Drainage area, soil infiltration, basin storage and base‐flow factor were the independent variables in the regression equations with the lowest standard error of estimate. The standard error of estimate ranged from 17% to 52% for the three river basins.     

Evaluation of spatial and temporal variation in Karun River water quality during five decades (1968–2014)

In the present study, the multivariate statistical technique cluster analysis (CA) is used to evaluate the spatial and temporal variations in the water quality data for the Karun River, which was gathered during 46 years of monitoring (from 1968 to 2014). The data recorded electrical conductivity (EC) in the river at six water monitoring stations along its course. The mean of EC was 972.05 ± 365.466 micromhos per centimeter (μmhos/cm) at the most upstream station and showed an increase to 1458.41 ± 675.048 μmhos/cm at the most downstream of the stations. By using hierarchical CA, the six sampling stations were grouped into three clusters of similar characteristics, which may be a result of different land uses in proximity to the stations. Furthermore, two‐way analysis of variance showed that EC had a significant correlation (p < 0.001) with the season, and the mean of the pollution depended on the level of the cluster and the season (spring, summer, autumn, and winter).     

闽江支流梯级电站开发对生态环境的影响及防治措施

采用现场调查监测，并结合收集的水电、渔业等方面资料，对闽江上游渔塘溪支流上的布上、碧州、马坪三级电站开发对植被、水土保持、水生植物、浮游生物、底栖动物、鱼类、水质的影响作了分析。结果表明，电站开发造成库区污染严重、富营养化、河段断流并产生一定的不利影响等。提出其环境减缓补救措施及今后闽江支流梯级电站开发生态环境保护的防治措施。     

Regional and Temporal Differences in Nitrate Trends Discerned from Long‐Term Water Quality Monitoring Data

Riverine nitrate (NO₃) is a well‐documented driver of eutrophication and hypoxia in coastal areas. The development of the elevated river NO₃ concentration is linked to anthropogenic inputs from municipal, agricultural, and atmospheric sources. The intensity of these sources has varied regionally, through time, and in response to multiple causes such as economic drivers and policy responses. This study uses long‐term water quality, land use, and other ancillary data to further describe the evolution of river NO₃ concentrations at 22 monitoring stations in the United States (U.S.). The stations were selected for long‐term data availability and to represent a range of climate and land‐use conditions. We examined NO₃ at the monitoring stations, using a flow‐weighting scheme meant to account for interannual flow variability allowing greater focus on river chemical conditions. River NO₃ concentration increased strongly during 1945‐1980 at most of the stations and have remained elevated, but stopped increasing during 1981‐2008. NO₃ increased to a greater extent at monitoring stations in the Midwest U.S. and less so at those in the Eastern and Western U.S. We discuss 20th Century agricultural development in the U.S. and demonstrate that regional differences in NO₃ concentration patterns were strongly related to an agricultural index developed using principal components analysis. This unique century‐scale dataset adds to our understanding of long‐term NO₃ patterns in the U.S.