营养盐水平对念珠藻胞外有机物产生的影响

以我国湖泊典型固氮蓝藻发状念珠藻(Nostoc flagelliforme)为研究对象,考察了氮、磷营养盐对发状念珠藻生长特性及其胞外有机物产生的影响.采用藻细胞浓度计数法表征发状念珠藻生长特性;分别采用溶解性有机碳(DOC)、三维荧光光谱(EEM)和紫外-可见光谱法,从总量和主要物质方面分析了发状念珠藻胞外有机物的产生规律.结果表明,在不同氮、磷营养水平下,发状念珠藻的4个关键生长时期基本相同,氮是控制发状念珠藻生长的关键营养控制要素;氮营养元素浓度的增高,有利于发状念珠藻产生胞外有机物,其产生量逐渐增大,而磷营养元素浓度的增高对胞外有机物产生量贡献较小,氮营养盐是发状念珠藻产生胞外有机物的关键限制因子;通过EEM谱图分析,发状念珠藻胞外有机物主要以类氨基酸类物质和类富里酸物质为主.以磷为控制营养盐时,类富里酸是主要的胞外有机物之一,以氮为控制营养盐时,类富里酸产生量极低;作为主要的胞外有机物,蛋白质和碳水化合物的产生规律显著不同,其中蛋白质含量显著高于碳水化合物含量.     

三阶段温度控制堆肥接种法对有机氮变化规律的影响

利用原生生活垃圾,通过三阶段温度控制技术进行堆肥试验,探讨在堆肥过程中有机态氮组分的动态变化规律.结果表明,全氮、酸水解有机态氮、氨基酸态氮均在堆肥的前期呈明显的下降趋势,呈较好的相关性.与CK（对照组）处理相比,在堆肥的后期,三阶段温度控制堆肥酸水解有机态氮、氨基酸态氮、氨基糖态氮及酸解未知态氮含量呈不同程度的上升趋势,增加幅度依次为：10.67%、16.17%、7.17%、22.44%.表明三阶段温度控制技术能减少堆肥中氮素的损失,堆肥产品施入土壤后,可提高土壤的供氮潜力.     

ZnOOH/O3催化臭氧化体系去除水中痕量对氯硝基苯

以实验室制备的羟基化锌（ZnOOH）为催化剂,考察了其催化臭氧化去除水中痕量对氯硝基苯（ppCNB能力.本实验条件下,蒸馏水中反应20　min时,催化臭氧化比单独臭氧化对pCNB的去除率提高了51 .3个百分点;催化过程遵循自由基反应机理,催化剂表面结合的羟基基团有利于催化反应;pCNB的去除效果随催化剂投量的增加而更佳,催化剂重复使用3次后,催化效果基本没有变化,水中的重碳酸盐以及缓冲溶液中的磷酸盐可以明显降低催化活性,中性条件下,催化作用最佳.     

好氧颗粒污泥膜生物反应器污泥性状研究

采用厌氧-好氧运行方式的颗粒污泥膜生物反应器（GMBR）,连续运行近120　d表现出良好的有机物去除及同步硝化反硝化能力.对GMBR中污泥粒径分布变化研究表明,GMBR中污泥浓度的增加主要是由于粒径0.18～0.45　mm的小颗粒污泥及小于0.18　mm的絮状污泥的增加造成的,粒径大于0.45　mm的颗粒污泥能够基本稳定维持其颗粒形态,反应器运行末期,GMBR中颗粒污泥（粒径大于0.18　mm的污泥）含量稳定在污泥总量的60％～65％以上.污泥表面电荷量随着污泥组成形态的变化电负性逐渐增加,80　d后稳定在-0.42～-0.80　meq·g^-1之间.污泥表面电荷的负电性增加主要是由小于0.45　mm的污泥造成的,其中小于0.18　mm的絮状污泥对其影响最大.并且,污泥粒径越大污泥表面负电荷量越少,两者具有较好的线性关系.另外,GMBR中SVI稳定在60～90 mL/g之间,并且随着污泥表面电荷负电性的增加污泥SVI值增加,两者之间具有一定的相关性.     

移动床生物膜反应器对垃圾渗滤液短程硝化研究

采用好氧移动床生物膜反应器（MBBR）对经过厌氧脱碳处理的垃圾渗滤液进行了深度短程硝化研究,考察了在中温（25℃）条件下DO浓度、pH值、C/N等因素对氨氮去除效果和短程硝化效果的影响.结果表明,在进水氨氮浓度为400　mg·L^-1,HRT为24 h情况下,当控制DO为2　mg·L^-1、pH值在8左右和C/N小于3时,氨氮去除率能达到70%以上,亚硝酸盐氮的积累率高达90％.间歇试验证明了该生物膜反应器中亚硝化菌的数量和活性要远高于硝化菌.该移动床生物膜工艺可以选择性固定和积累氨氧化细菌,从而实现较高的氨氮去除率和稳定的亚硝酸盐氮积累率.     

Spatial distribution of aerosol pollution based on MODIS data over Beijing, China

With the help of regression analysis,the relationships were detected between aerosol's contribution to apparent reflectance(ACR) derived from Moderate Resolution Imaging Spectroradiometer(MODIS)on board Terra and hourly PM_(10)mass concentration measured at 30 ground-based locations in Beijing for the August of 2003 and 2004.It was shown that there was a good correlation between the ACR and PM_(10)(linear correlation coefficient,R=0.56).On the basis of this relationship,spatial distribution and possible sources of PM_(10)derived from MODIS were analyzed and two frequently heavily-polluted regions were found,namely downtown of the city and the district near Xishan Mountain.These two regions coincidently are also urban heat island centers.The foundings of this paper will be greatly useful for environmental monitoring and urban planning for Beijing,especially for the 2008 Olympic game to be held in Beijing.     

Bioaccumulation of heavy metals in fishes from Taihu Lake, China

The Cr,Zn,Cu,Cd,Pb contents were determined in Cyprinus carpio Linnaeus,Carassius auratus Linnaeus,Hypophthalmichthys molitrix and Aristichthys nobilis,which were caught from Meiliang Bay,Taihu Lake,a large,shallow and eutrophic lake of China.The results showed that:(1)the Cr,Cu,Pb,Cd contents in the edible parts of the four fish species were much lower than Chinese Food Health Criterion(1994),but the Zn contents were higher than the Criterion;(2)Cd contents were the highest in the liver of fish,Pb contents were almost the same in all organs of fish,Cr contents mainly enriched in the skin and gonads,Zn contents were the highest in the gonad(♀),and Cu contents were the highest in the liver;(3)the total metal accumulation was the greatest in the liver and the lowest in the muscle.The total metal accumulation was the highest in C.auratus L.This investigation indicated that fish products in Taihu Lake were still safe for human consumption,but the amount consumed should be controlled under the Chinese Food Health Criterion to avoid excessive intake of Zn.     

Distribution characteristics of dissolved organic carbon in annular wetland soil-water solutions through soil profiles in the Sanjiang Plain, Northeast China

Overwhelming evidence reveals that concentrations of dissolved organic carbon （DOC） have increased in streams which brings negative environmental impacts. DOC in stream flow is mainly originated from soil-water solutions of watershed. Wetlands prove to be the most sensitive areas as an important DOC reserve between terrestrial and fluvial biogeosystems. This reported study was focused on the distribution characteristics and the controlling factors of DOC in soil-water solutions of annular wetland, i.e., a dishing wetland and a forest wetland together, in the Sanjiang Plain, Northeast China. The results indicate that DOC concentrations in soilwater solutions decreased and then increased with increasing soil depth in the annular wetland. In the upper soil layers of 0-10 cm and 10-20 cm, DOC concentrations in soil-water solutions linearly increased from edge to center of the annular wetland （R^2 = 0.3122 and R^2 = 0.443）. The distribution variations were intimately linked to DOC production and utilization and DOC transport processes in annular wetland soil-water solutions. The concentrations of total organic carbon （TOC）, total carbon （TC） and Fe（II）, DOC mobility and continuous vertical and lateral flow affectext the distribution variations of DOC in soil-water solutions. The correlation coefficients between DOC concentrations and TOC, TC and Fe（II） were 0.974, 0.813 and 0.753 respectively. These distribution characteristics suggested a systematic response of the distribution variations of DOC in annular wetland soil-water solutions to the geometry of closed depressions on a scale of small catchments. However, the DOC in soil pore water of the annular wetland may be the potential source of DOC to stream flow on watershed scale. These observations also implied the fragmentation of wetland landscape could bring the spatial-temporal variations of DOC distribution and exports, which would bring negative environmental impacts in watersheds of the Sanjiang Plain.     

日本森林大气中过氧化物的浓度及其对森林植物的影响

为了研究森林衰退的原因,于2000,2001和2002年的8月,分别选择出现森林衰退的日本奥日光白根山落叶树森林和未出现森林衰退的长野县大芝高原红松森林设立监测点,对光化学氧化剂臭氧(O3)和过氧化物的浓度进行监测,同时利用人工气候室对森林植物山毛榉和白桦进行了50′10-9O3、100′10-9O3和50′10-9O3+2′10-9~3′10-9过氧化物(过氧化氢(H2O2)及甲基过氧化氢(MHP))的暴露实验.野外监测结果表明,监测期间奥日光和长野的O3平均浓度相同,奥日光的H2O2及MHP平均浓度均高于长野;大气中的H2O2和MHP总是与O3共存,并且其浓度随O3浓度的增加而增加.暴露实验结果表明,暴露于50′10-9O3+2′10-9~3′10-9过氧化物的山毛榉和白桦出现了不同于O3暴露的叶片伤害症状;与100′10-9O3相比,50′10-9O3+2′10-9~3′10-9过氧化物导致植物出现了严重的叶片伤害和显著的光合速率下降.研究结果表明,除O3外,大气中的过氧化物也是导致森林衰退的原因之一.     

电沉积法处理电解锌漂洗废水的动力学研究

采用电沉积法处理电解锌漂洗工艺废水,以回收废水中的重金属资源。在不同实验条件下对电沉积反应过程中电沉积反应速率及其影响因素进行了研究,结果表明,电沉积回收重金属锌符合准一级动力学规律,当V=6 V时,速率常数k=0.0214。最佳实验条件为:槽电压V=6 V、电解时间为45~60 min、pH为2.5~3.5,反应过程中应充分搅拌。利用电沉积法处理电解锌漂洗废水,将重金属Zn2+还原为单质锌,处理废水的同时实现重金属资源的回收,在工业中有较好的应用前景。