多级土壤渗漏系统处理农村生活污水

构建了多级土壤渗漏系统（MSL）以处理农村生活污水,主要研究了MSL的挂膜启动特征,进水水力负荷对MSL处理生活污水性能的影响,以及MSL运行过程中生物膜的特征.实验结果表明,采用连续进水的方式挂膜28d后,挂膜成功,MSL对生活污水中COD,氨氮,TN,TP的去除率分别达到84.5%,74.7%,66.7%,76.4%.MSL运行过程中,表现出对进水水力负荷变化较强的适应性,水力负荷为400L/（m²·d）时,生活污水中COD,氨氮,TN,TP的平均去除率分别达到93.4%,94.9%,80.4%,94.7%,系统出水水质能够满足城镇污水处理厂污染物排放标准（GB18918-2002）一级A标准.MSL对有机物和氮磷的去除途径结果表明,微生物降解和转化作用对污水中COD,氨氮,TN的去除贡献率最大,Fe³⁺与PO₄^3-的化学沉淀作用则是TP去除的主要途径.实时荧光定量PCR技术检测结果显示,生物膜中硝化功能菌占总菌群的35.5%.     

Volatilization and Biodegradation of VOCs in Membrane Bioreactors (MBR)

Volatilization and biodegradation are major competitive volatile organic compound (VOC) removal mechanisms in biological wastewater treatment process, which depend on compound specific properties and system design/operational parameters. In this study, a mathematical model was used to determine major removal pathways at various organic loading rates (OLR), solids residence time (SRT) and dissolved oxygen (DO) concentrations in a biological process for vinyl acetate. Model results showed that biological treatment process should be designed with long SRT, high OLR and low DO concentrations to maximize biodegradation and minimize volatilization of VOCs. Unless a VOC is toxic to microorganisms under the given conditions, low VOC emission rates are an inherent advantage of MBRs, which operate at higher OLR and longer SRT compared to conventional activated sludge process. A lab scale membrane bioreactor (MBR) was operated at varying OLR to investigate the relative volatilization and biodegradation rates for acetaldehyde, butyraldehyde and vinyl acetate. Synthetic wastewater containing three VOCs was introduced to the MBR. The DO concentration and SRT was maintained at 2.0 mg L^{− 1} and 100 days, respectively. The overall VOC removal rate was more than 99.7% for three VOCs at all the OLR. For vinyl acetate, the biodegradation rate increased from 93.87 to 99.40% and the volatilization removal rate decreased from 6.09 to 0.59% as OLR was increased from 1.1 to 2.0 kg COD m^{− 3} d^{− 1}. It was confirmed that a MBR can be a promising solution to reduce VOC emissions from wastewater.     

解析研究内部爆炸驱动金属圆筒的运动

从柱壳运动的控制方程出发，应用壳壁发生贯穿破裂的Taylor判据，给出了内部爆炸加载下金属圆筒壳壁的运动轨迹、平均破裂时间、破裂应变、半径及破片初速度的解析表达式。结果表明：计算结果与相关文献中的实验结果基本符合。     

江苏省近47年来的梅雨特征及灾害影响

利用江苏省气象台1954～2000年的梅雨期降水资料，采用趋势分析方法，对江苏省的梅雨变化特征进行了分析研究。结果表明：近47年来江苏省梅雨量年际变化大致可以分为少雨和多雨两个阶段；梅雨的区域分布特征是苏南及沿江地带梅雨量的年波动不及淮北地区；各年份梅雨持续的天数相差极为悬殊，而其降水极值除个别年份外大多低于800mm；梅雨量的丰歉常常决定了江苏省的旱涝总趋势，特别的丰梅年和枯梅年对江苏省农业生产和社会经济发展都带来显著的负面影响。     

LEAF LITTER BREAKDOWN IN A RECENTLY IMPOUNDED RESERVOIR1

ABSTRACT: The impoundment of Richard B. Russell Lake resulted in the inundation of 3490 ha of forested area or 33 percent of the total area of the lake. Estimates of the total inundated leaf litter biomass were combined with a leaf litter decomposition study to determine the nutrient load and dissolved oxygen demand to the reservoir. Hickory leaf bags broke down most rapidly at the 3-m and 28-rn depths, followed by short-needle pine, white oak, a hardwood litter mixture, beech, and red oak. Leaf bags incubated at the 3-m depth exhibited significantly higher breakdown rates than those at the 28-m depth for most leaf types, due to differences in dissolved oxygen and temperature. Respiration rates of litter were also higher at the 3-m depth. Most leaf types accumulated nitrogen and phosphorus and lost organic carbon after an initial leaching period. Richard B. Russell Lake exhibited extensive anoxia and the buildup of total organic carbon, nitrogen, and phosphorus during summer stratification. Leaf litter breakdown accounted for 64 percent of the organic carbon increase but acted as a sink for nitrogen and phosphorus. The dissolved oxygen demand of the litter accounted for over 50 percent of the demand incurred in the lake.     

NONPARAMETRIC STATISTICAL ANALYSIS OF ANNUAL PEAK FLOW DATA FROM A RECENTLY URBANIZED WATERSHED1

ABSTRACT. In order to demonstrate the feasibility of a nonparametric statistical application in investigating the hydrologic impact of the rapid land use change accompanying intense urbanization, annual maximum peak flow data from an actual example (the Northeast Branch Basin, a recently urbanized Washington, D.C., suburban watershed) were analyzed. Annual peak flow data from the Patuxent Basin above Unity, Maryland, a rural watershed in close proximity to the study area, were compared to data from the Northeast Branch for the Same period utilizing the Wilcoxon matched-pairs signed-ranks test. A change in central tendency of each series was noted at the 0.01 significance level; however, the change was negative in the rural basin and positive in the urbanized Northeast Branch Basin. This central tendency change was considered indicative of an average decrease in the size of rainstorms producing annual maximum peak discharges. Rainstorm data from the Northeast Branch Basin were divided into two equal periods (before urbanization and after) and the Wilcoxon test was applied. It was found that rainstorms producing maximum annual peak discharges in the urbanized period were indeed smaller than those in the prior period (0.01 level of significance); however, larger annual peaks were produced. It was concluded that nonparametric statistical methods can be used readily with conventional methods to isolate and clearly analyze the various problems in an actual urban hydrologic study.     

沱江氮污染物转化规律及污染容量

本文研究氮污染物在沱江水体中的转化规律及其主要的影响因素。通过实验室模拟试验和野外现场水团追踪试验求得氨氮在沱江水中的总消失速度常数k_T、硝化速度常数k_N、温度校正系数θ以及氨氮的耗氧系数f_n。在参数计算方法上较前人有所改进。建立了计算沱江氮污染容量的数学模式,并用该模式估算了沱江在不同流量和不同水温条件下所能容纳氮污染物的负荷量。     

华北平原东部全新世古年地表径流量的估算

利用以现代数据建立的年平均降水量、年平均温度与年平均地表径流深间的关系式和全新世古年降水量、古年温度的推测值估算了华北平原东部的全新世古年地表径流深,并将估算结果与已有的古水文数据作了对比。     

Initial results from a multi-institutional collaboration to monitor harmful algal blooms in South Carolina

The rapid rate of development in the South Carolina (SC) coastal zone has heightened public concern for the condition of the state's estuaries, and alerted scientists to the potential that novel and adverse effects on estuarine ecosystems may result. Although well-developed databases from long-term monitoring programs exist for many variables valuable in predicting and following system responses, information on phytoplankton distributions in SC estuaries has lagged. Knowledge of the dynamical relationship between environmental (e.g., nutrient quantity and quality) and biological (e.g., grazing) regulation, and phytoplankton biomass and composition is critical to understanding estuarine susceptibility to eutrophication or harmful algal blooms (HABs). Recently, SC scientists from federal, state, and academic institutions established a collaborative monitoring program to assess HAB distribution and ecology statewide. The South Carolina Harmful Algal Bloom Program includes: a) intensive temporal monitoring at areas of known HAB occurrence or those exhibiting symptoms potentially related to HABs (e.g., prevalent fish lesions), b) extensive spatial monitoring in coordination with existing statewide efforts, c) a citizen volunteer monitoring network, d) nutrient response bioassays, and e) laboratory-based physiological experiments on HAB isolates. By combining trip-wire surveillance and rapid response systems, routine monitoring of environmental parameters and HAB distribution, and process-oriented studies examining the physiological functioning of HAB species, an enhanced understanding of the impact and environmental control of HABs in SC estuaries will be achieved. The application of this approach to studies on the distribution and physiological ecology of a new widespread SC red tide, and to the discovery of several potentially toxic blooms (including Pfiesteria) in SC holding ponds, are described.     

城市径流质量模型参数率定方法研究

本文针对某一具体城市集水区，简要介绍一种污染物集聚模型和冲洗模型参数的率定方法。该方法概念清晰，操作简便，且成果符合实际，有一定精度。