Micro-analysis of nitrogen transport and conversion inside activated sludge flocs using microelectrodes

To investigate the nitrogen transport and conversion inside activated sludge flocs, micro-profiles of O₂, NH₄⁺, NO₂^–, NO₃^–, and pH were measured under different operating conditions. The flocs were obtained from a laboratory-scale sequencing batch reactor. Nitrification, as observed from interfacial ammonium and nitrate fluxes, was higher at pH 8.5, than at pH 6.5 and 7.5. At pH 8.5, heterotrophic bacteria used less oxygen than nitrifying bacteria, whereas at lower pH heterotrophic activity dominated. When the ratio of C to N was decreased from 20 to 10, the ammonium uptake increased. When dissolved oxygen (DO) concentration in the bulk liquid was decreased from 4 to 2 mg·L^-1, nitrification decreased, and only 25% of the DO influx into the flocs was used for nitrification. This study indicated that nitrifying bacteria became more competitive at a higher DO concentration, a higher pH value (approximately 8.5) and a lower C/N.     

广西漓江洪涝灾害及防御对策研究

利用GIS信息系统和降水实况资料,对发生在广西漓江的洪涝情况进行分析。通过对洪涝灾害进行实地调查,利用灾害风险评估技术,对漓江洪涝灾害进行风险区划,对洪涝灾害的防御措施进行探讨。漓江上游是广西的暴雨中心,汛期暴雨常造成漓江洪涝灾害,特别是5-6月份,每年基本上都有2~3次大面积的洪灾;沿江两岸都是洪涝灾害的高风险区;漓江洪水具有来得快,消得也快的特点;造成漓江致洪暴雨的天气形势主要是华南静止锋;加强上游降水量的监测和预报,加强上游水库蓄水错峰的调控能力,完善低洼地段防洪堤坝建设,可以有效地防御洪涝灾害。     

厌氧-两级SBR法处理高浓度洋蓟废水的研究

采用厌氧两级SBR工艺处理洋蓟罐头生产排放的高浓度有机废水,确定了厌氧、SBR工艺的最佳运行参数。结果表明,通过该工艺处理后,COD的总去除率达到98%以上,出水COD为78mg/L,达到国家排放标准。     

层次分析法与向量模法在水环境承载力评价中的应用——以胶州市为例

从社会经济、资源利用、与环境管理等角度分析了胶州市水环境承载力的主要影响因素,综合构建了胶州市水环境承载力评价指标体系。采用层次分析法和向量模法对胶州市2007~2011年水环境承载力进行了评价。结果表明,胶州市水环境承载力评价值范围为0.061~0.080,胶州市水环境承载力水平较低,总体上呈先下降后上升的趋势,其中,水资源短缺为制约胶州市水环境承载力的主要因素。     

Simulated photo-degradation of dissolved organic matter in lakes revealed by three-dimensional excitation-emission matrix with regional integration and parallel factor analysis

Simulated photo-degradation of fluorescent dissolved organic matter(FDOM) in Lake Baihua(BH) and Lake Hongfeng(HF) was investigated with three-dimensional excitationemission matrix(3 DEEM) fluorescence combined with the fluorescence regional integration(FRI),parallel factor(PARAFAC) analysis,and multi-order kinetic models.In the FRI analysis,fulvic-like and humic-like materials were the main constituents for both BH-FDOM and HF-FDOM.Four individual components were identified by use of PARAFAC analysis as humic-like components(C1),fulvic-like components(C2),protein-like components(C3) and unidentified components(C4).The maximum 3 DEEM fluorescence intensity of PARAFAC components C1-C3 decreased by about 60%,70% and 90%,respectively after photo-degradation.The multi-order kinetic model was acceptable to represent the photo-degradation of FDOM with correlation coefficient(R_(adj)~2)(0.963-0.998).The photo-degradation rate constants(k_n) showed differences of three orders of magnitude,from 1.09 x 10~(-6) to 4.02 x 10~(-4) min-1,and half-life of multi-order model(T_(1/2)~n)ranged from 5.26 to 64.01 min.The decreased values of fluorescence index(FI) and biogenic index(BI),the fact that of percent fluorescence response parameter of Region I(P_(Ⅰ,n)) showed the greatest change ratio,followed by percent fluorescence response parameter of Region II(P_(Ⅱ,n),while the largest decrease ratio was found for C3 components,and the lowest T_(1/2)~n was observed for C3,indicated preferential degradation of protein-like materials/components derived from biological sources during photodegradation.This research on the degradation of FDOM by 3 DEEM/FRI-PARAFAC would be beneficial to understanding the photo-degradation of FD OM in natural environments and accurately predicting the environmental behaviors of contaminants in the presence of FDOM.     

大气臭氧总量的一个统计计算方法

根据大气臭氧和太阳紫外辐射的观测资料，利用相关分析，得到了计算臭氧总量的一个统计计算方法，并计算了１９９１年北京地区晴天和实际天然条件下臭氧总量的月平均值，计算结果表明，计算值与观测值吻合得比较好，计算值与观测值相对偏差的平均值小于２．５％，大气中的光化学反应是影响臭氧总量的主要因子。     

Spatial distribution and ecological risk assessment of heavy metals in surface sediments from a typical plateau lake wetland, China

Surface sediment (0-15 cm) samples were collected from 31 different grid points throughout the Yilong Lake in April 2004. Samples were subjected to a total digestion technique and analyzed for As, Cd, Cr, Pb, Ni, Cu, and Zn in order to study spatial distribution characteristics based on Kriging method and assess their ecological risks posed by these heavy metals. Results showed that the mean concentrations of these heavy metals were lower than potential effect levels. Patches of higher heavy metal concentrations occurred in the inflow area of the Cheng River and northeast area nearby the road and railway. The higher concentrations of As and Cr also appeared in the east area (lake outlet), while the patches of lower concentrations were uniformly distributed at the southwest corner between Luosewan and Xiaoguoxi. The heavy metal loads such as As, Cd and Pb might come from the common sources due to industrial sewage and traffic pollution, while higher concentrations of Ni, Cr, and Zn in these sediments were dominated by parent rocks. However, Cu originated from both sources. Sediments with respect to As, Cd and Cu were grouped below the effect range low (ERL) at all sites, and with respect to Cr and Pb were grouped into the range from ERL to the effect range median (ERM) at more than 50% of sampling sites. The mean heavy metal toxic units in the Yilong Lake decreased following the order Pb > Cr > As > Ni > Zn > Cd > Cu, with higher contributions to the sum of toxic units of Pb, Cr and As.     

吉林省西部农牧交错区不同土地利用方式对土壤线虫群落特征的影响

对吉林省西部农牧交错区典型生境土壤线虫群落进行调查,共捕获线虫23属、1 264只,优势属为真滑刃属和短体属。研究结果显示,土地利用方式对土壤线虫群落特征有一定影响,不同生境间土壤线虫群落共有属不多,农业生产活动促使土壤线虫向土壤下层移动;不同农业生产活动对土壤线虫群落多样性影响不同, 4种生境中,居民点园地土壤线虫群落多样性最高,而玉米田最低;不同土地利用方式下土壤线虫功能类群差异显著,玉米田不利于捕食类群/杂食类群的存在。     

"二重源解析"技术及其系统实现

化学质量平衡是被广泛用于空气质量管理的受体模型之一.由于混合源(城市扬尘)和单一源因颗粒物源谱的严重共线性,采用美国环境保护署推荐使用的EPA-CMB8.2,无法定量解析出各排放源初始态和扬尘态颗粒物的贡献值和分担率.针对这一问题,完善和规范了"二重源解析"技术原理,开发了具有"二重源解析"功能的NKCMB3.0.对鞍山市样品污染物来源解析的试验结果表明,"二重源解析"技术在对混合源和单一源同时进行源解析时是有效的.     

Assessment of heavy metal pollution in wetland soils from the young and old reclaimed regions in the Pearl River Estuary, South China

Soils were sampled in three types of wetlands from the young (A) and old (B) reclaimed regions of the Pearl River Estuary. They were analyzed for total concentrations of heavy metals to investigate their distributions and pollution levels in both regions. Results showed that most heavy metals in ditch and riparian wetlands did not significantly differ from those in reclaimed wetlands in A region, while significantly lower for Cd, Cu, Pb, and Zn in reclaimed wetlands in B region, suggesting higher effects of long-term reclamation. Iron, Cr and Cu were identified as metal pollutants of primary concern and had higher contributions to the total toxic units compared to other metals. Almost all metals exceeded their lowest effect levels and Fe and Cr even exceeded the severe effect levels. Multivariate analysis shows that Fe and Mn are controlled by parent rocks and other metals mainly originate from anthropogenic source.