Modeling Nutrient Export From Coastal California Watersheds

Nitrate and phosphate export coefficient models were developed for coastal watersheds along the Santa Barbara Channel in central California. One approach was based on measurements of nutrient fluxes in streams from specific land use classes and included a watershed response function that scaled export up or down depending on antecedent moisture conditions. The second approach for nutrient export coefficient modeling used anthropogenic nutrient loading for land use classes and atmospheric nutrient deposition to model export. In an application of the first approach to one watershed, the nitrate and phosphate models were within 20% of measured values for most storms. When applied to another year, both nitrate and phosphate models generally performed adequately with annual, storm‐flow, and base‐flow values within 20% of measured nutrient loadings. Less satisfactory results were found when applied to neighboring watersheds with difference percentages of land use and hydrologic conditions. Application of the second approach was less successful than the first approach.     

土坡滑坡应急处置技术与防控机理研究

为适应滑坡应急处置的需要,在分析常见滑坡防控措施与机理后,选用螺旋锚作为应急处置的技术手段,研制开发了车载施工设备,大大提高了快速反应能力与机动性。对于降雨渗水引起的滑坡,提出了锚固与反滤导渗相结合的防控机理,综合提高坡体的稳定性。该技术方法具有处置速度快、劳动强度低的特点。     

上海霾与非霾期间大气颗粒物光学特性垂直分布特征和质量浓度对比研究

采用美国国家航空航天局的云-气溶胶激光雷达红外开拓者卫星搭载的正交极化云-气溶胶激光雷达数据产品,包括消光系数、光学厚度、总后向散射系数、体积退偏比和色比,结合地面监测的颗粒物质量浓度,分析上海大气相对湿度小于80%霾发生期间气溶胶光学属性的垂直分布特征和颗粒物质量浓度变化,并与非霾期间进行比较.结果表明:霾期间532 nm和1064 nm消光系数在垂直高度上(海拔:0~10 km)均大于非霾期间,且大多数霾期间颗粒物在整层大气的光学厚度大于非霾期间.在近地面,霾期间大气颗粒物散射能力大于非霾期间.各垂直高度层,霾与非霾期间小粒径和规则气溶胶占主导地位.霾期间近地面大粒径颗粒物在霾期间所占比例大于非霾期间;2.0~4.0 km高度层,霾和非霾期间细颗粒所占比例接近;4.0~10.0 km高度层,霾期间细颗粒气溶胶所占比例大于非霾期间.PM1、PM2.5和PM10质量浓度在霾期间均大于非霾期间,且霾期间细颗粒物所占比例明显增加.颗粒物质量浓度和比值PM1/PM2.5和PM2.5/PM10分别随霾污染程度的加重而升高.冬季颗粒物质量浓度最高,主要来自细颗粒物的贡献;而春季PM10质量浓度高于其它季节.     

Experimental study on MSW gasification and melting technology

In order to develop municipal solid waste (MSW) gasification and melting technology, two preliminary experiments and a principle integrated experiment were fulfilled respectively. The gasification characteristics of MSW are studied at 500-750℃ when equivalence ratio (ER) was 0.2-0.5 using a fluidized-bed gasifier. When temperature was 550-700℃ and ER was 0.2-0.4, low heat value (LHV) of syngas reaches 4000-12000 kJ/Nm3. The melting characteristics of fly ash were investigated at 1100-1460℃ using a fixed-bed furnace. It was proved that over 99.9% of dioxins could be decomposed and most heavy-metals could be solidified when temperature was 1100-1300℃. The principle integrated experiment was carried out in a fluidized-bed gasification and swirl-melting system. MSW was gasified efficiently at 550-650℃, swirl-melting furnace maintains at 1200-1300℃ stably and over 95% of fly ash could be caught by the swirl-melting furnace. The results provided much practical experience and basic data to develop MSW gasification and melting technology.     

活性污泥异常膨胀原因分析

分析污水在生化过程中出现污泥膨胀的原因,主要体现在污泥沉降性能下降,采用相应的解决措施,使污泥的活性得到改善,从而解决污泥膨胀问题。     

丹江口水库典型入库支流氮磷动态特征研究

重污染的神定河(接收城市污染)、中污染的大柏河(接收城镇污染)以及轻污染的五龙池(接收轻微农业面源污染)是丹江口水库3条典型入库支流.在2010年4月～2011年4月对这3条入库支流及其河口水质监测的基础上,分析了水中氮、磷的动态变化特征,并利用综合营养状态指数法对其营养状态进行评价.结果表明,神定河的TN、TP全年浓度均值分别为11.63 mg.L-1、0.93 mg.L-1,与五龙池(TN为4.41 mg.L-1,TP为0.076 mg.L-1)相比分别超过3倍和12倍;大柏河的TN、TP全年浓度均值分别为4.79 mg.L-1、0.15 mg.L-1,略高于五龙池中TN、TP浓度均值.3条支流及其河口中营养盐的时间差异为TN浓度在丰水期低于枯水期,而多数支流中TP浓度在枯水期低于丰水期.神定河中NH4+-N占TN的质量分数高达69%,其它支流及河口中NH4+-N占TN的质量分数均低于20%.NO3--N浓度变化范围为1.3～2.7 mg.L-1,SRP占TP的质量分数为30%～45%.神定河及其河口氮、磷营养元素比例关系研究表明神定河总体处于氮限制状态,河口总体处于磷限制状态.综合营养状态指数评价显示3条典型污染入库支流及其河口都处于富营养化状态,轻污染的五龙池的入库河口(东库湾)处于轻度富营养化状态.     

DO C/N对同步硝化反硝化影响的试验研究

在序批式活性污泥反应器(SBR)内,以模拟的城市污水为处理对象,研究DO、C/N等因素对同步硝化反硝化脱氮效率的影响。研究表明:采用连续曝气工艺,在进水COD=200mg/L,NH4+-N=30mg/L条件下,控制DO在0.5～1.5mg/L范围内时,出水TN浓度为1.98～6.3mg/L,TN的平均去除率在80%以上,最高去除率达到93.74%,并可推断出在反应系统内存在好氧反硝化菌;C/N在3.3～10之间时,C/N越高,出水NO3--N浓度越低,SND效果越好。     

Impact of land-use types on nitrate concentration and δN in unconfined groundwater in rural areas of Korea

An understanding of the long-term changes in the nitrate contamination pattern of unconfined groundwater is critical to conservation of drinking water in rural areas supporting mixed land-use activities such as cropping, livestock farming, and residence. To examine the effect of different land-use activities on nitrate contamination, groundwater samples were collected monthly for 3 years (1997–1999) from 12 wells in rural areas with different land-use activities and analyzed for the concentrations and N isotopic ratios (δ¹⁵N) of nitrate. The characteristics of nitrate contamination clearly differed with land-use activities. The percentages of samples that had a nitrate concentration exceeding the national standard for drinking water (10 mg N L⁻¹) were 0, 23, 43, and 67% for the uncontaminated natural area, cropping area, cropping-livestock farming complex area, and residential area, respectively. The range of δ¹⁵N values was between +1.4 and +4.5‰ for groundwater nitrate from the uncontaminated natural area. In the cropping area, the δ¹⁵N values were slightly different with the type of fertilizer applied to fields in the vicinity of the well, and the values ranged between +8.7 and +14.4‰ for the compost-applied area and between +4.5 and +8.5‰ for the area where urea was applied with compost. The δ¹⁵N values of the cropping-livestock farming complex area ranged from +1.0 to +17.7‰, probably resulting from mixed contamination sources (inorganic fertilizer and livestock manure). The well located closest to the livestock feedlot had relatively higher δ¹⁵N values, with a range between +8.7 and +17.6‰. In the residential area, a higher δ¹⁵N (most frequently above +10‰) of nitrate suggested that the major source of contamination was effluent from leaky septic tanks. Our data showed that unconfined groundwater is susceptible to land-use activities above the aquifers, and the impacts of the activities could be more precisely inferred from long-term data on the concentration and δ¹⁵N of nitrate. By determining the impacts, more effective (specific to contamination sources) measures for preventing groundwater quality could be implemented.     

Effect of nutrient level on phytoplankton community structure in different water bodies

Increasing levels of pollution within water bodies can cause eutrophication and an associated rapid growth in and reproduction of phytoplankton. Although most frequently occurring in bodies of water such as lakes and dams, in recent years an increasing number of river systems in China have suffered serious algal blooms. The community structure of phytoplankton may differ, however, dependent on the hydrodynamic conditions and nutrient levels within the water body. The field investigation results obtained from a stagnant river in Suzhou City and Taihu Lake, China, showed that in water with higher concentrations of nitrogen and phosphorus, Chlorophyta became the predominant species and in water with lower concentrations of nitrogen and phosphorus, Cyanobacteria became the predominant species. Growth experiments with competitive species, Microcystis aeruginosa Kütz and Scenedesmus quadricauda (Turp.), were conducted at three different nutrient levels. The biomass of algae in pure and mixed cultures was measured under conditions of different N/P ratios at oligotrophic, eutrophic and hypertrophic nutrient levels. The results indicated that the most suitable state for the growth and reproduction of M. aeruginosa and S. quadricauda were eutrophic conditions in both pure and mixed cultures. Under competition, however, the lower medium nutrient levels favoured M. aeruginosa, while the higher medium nutrient levels better suited S. quadricauda. Under similar hydrodynamic conditions, the community structure of phytoplankton in the water body was determined by the dominant species in competition for nutrients.     

浅述汽车加油站油气回收系统监测研究

加油站油气回收系统是由卸油油气回收系统、汽油密闭储存、加油油气回收系统、在线监测系统和油气排放处理装置组成。该系统的作用是将加油站在卸油、储油和加油过程中产生的油气,通过密闭收集、储存和送入油罐汽车的罐内,运送到储油库集中回收变成汽油,以达到在汽车加油、油料储运过程中油汽不外泄,不污染周边环境的目的。根据中华人民共和国《加油站大气污染物排放标准》(GB 20952-2007)中第六条的规定,长三角地区的改造项目应在2010年1月1日进行,因此对加油站油气回收系统的监测显得十分紧迫。