磺胺和四环素类抗生素对活性污泥性能的影响

废水处理工艺中抗生素类污染物的存在可能会对生物处理过程产生长期而深远的影响,为探明此类污染物对废水生物处理主体活性污泥性能等方面的影响,采用间歇培养法研究了活性污泥法处理污水时,抗生素类污染物的存在对活性污泥性能如胞外聚合物（EPS）、污染物处理能力、脱氢酶活性和群落结构的影响。结果表明,抗生素的存在会导致活性污泥的胞外聚合物总量及其主要组分蛋白质和多糖增加,以产生保护屏障;且由于污泥絮体解体,细胞破裂导致EPS中DNA和色氨酸含量增加。同时,由于蛋白质大量增加引起的表面负电荷的增加,使污泥疏水性增强,絮凝性能恶化;污泥絮体解体导致污泥颗粒变小,SVI也随之下降;在活性污泥脱氢酶活性急剧下降的同时,出水TOC迅速升高。此外,抗生素类污染物在抑制活性污泥中大部分细菌的同时,对部分菌群也有刺激生长作用,最终导致活性污泥生物群落结构的改变。四环素类抗生素对活性污泥的EPS和絮凝沉降性能的影响大于磺胺类,而对污水处理能力和群落结构的影响则不如磺胺类。抗生素类污染物的长期存在会对活性污泥沉降性能、絮凝性能、脱氢酶活性以及活性污泥群落结构等产生一系列负面影响,进而影响污染物去除效果,导致出水水质恶化。     

不同挂膜方式生物滴滤塔处理含H2S恶臭气体

采用菌剂挂膜,活性污泥挂膜和自然挂膜3种不同方式形成生物滴滤塔,考察挂膜方式对生物滴滤塔去除H2s恶臭气体的影响。结果表明,当进气H2S浓度为5mg／m3时,菌剂挂膜、活性污泥挂膜、自然挂膜形成的生物滴滤塔出气H2s浓度分别为15．7～17．4、11．6～14．8和15．0～15．9μg／m3;塔内压降分别为3—4mm水柱、6mm水柱和4—5mm水柱;喷淋后滤出液中硫酸根的浓度分别为14、22和17mg／L,硫的转化率分别为45％、60％和50％。当进气H2S浓度增大至7mg／m3时,3个塔经过7d的调整后,均能达到稳定状态,稳定后3个塔中出气H2s浓度和压降基本没变,喷淋后滤出液中硫酸根浓度依次增大至25、31和30mg／L左右。采用活性污泥挂膜形成的生物滴滤塔处理H2s的能力比菌剂挂膜和自然挂膜的高。     

亚硝态氮对同时产甲烷反硝化工艺处理畜禽粪水的影响

为进一步提高同时产甲烷反硝化反应对畜禽粪水化学需氧量(COD)和氮的去除效率,应用畜禽粪水于接种颗粒污泥的厌氧混合式反应器,进行不同COD与亚硝态氮浓度比值(COD/NO-2-N)对同时产甲烷反硝化反应的影响研究。通过实时监测反应器内COD、凯氏氮(TKN)、辅酶F420、β-葡萄糖苷酶、产气率、pH和氧化还原电位(ORP)等指标得出,COD/NO-2-N为30/1、40/1时,COD去除率、辅酶F420和β-葡萄糖苷酶含量与空白无亚硝态氮的变化规律一致,亚硝态氮几乎未对糖类水解菌及产甲烷菌活性产生抑制作用;而COD/NO-2-N为10/1、20/1时,COD去除率、辅酶F420和β-葡萄糖苷酶含量较低,糖类水解菌及产甲烷菌活性受到抑制。     

温度对SBR单级好氧生物除磷性能的影响

以合成废水为研究对象,以丙酸钠作为单一碳源,分别设置温度为5、15、25、35℃的4组序批式反应器(R1、R2、R3、R4),考察了温度对单级好氧工艺除磷的影响。结果表明,稳定运行阶段,R1、R2、R3、R4出水磷浓度分别为4.05、2.17、1.34和0.11 mg/L,去除效率分别为61.5%、79.3%、87.2%和99.0%,吸磷速率分别为0.501、1.432、2.538和3.700mg P/(g VSS·h),即提高温度有利于磷的去除。此外,各反应器中多聚磷酸盐激酶(PPK)和外切磷酸盐酶(PPX)活性分别为0.093、0.213、0.376、0.549 U和0.010、0.019、0.029、0.025 U,导致吸磷速率和释磷速率随之增大,可知温度影响聚磷菌PPK和PPX的活性,从而影响除磷效果。静置阶段,聚磷菌体内储能物质糖原质和聚羟基脂肪酸酯基本保持不变,但各反应器均出现了释磷现象,聚磷作为主要供能物质,单位释磷量分别为1.95、6.42、9.90和9.56 mg P/(g TSS),提高温度可促进静置段聚磷分解提供能量,从而驱动好氧吸磷达到更好的除磷效果。     

长江口滩涂湿地景观变化对典型水鸟生境适宜性的影响

近年来在海平面上升、长江水沙变化、植被演替等自然因素以及促淤圈围工程、深水航道建设等人为因素的共同作用下,长江口滩涂湿地水鸟适宜生境发生了巨大变化。针对长江口滩涂湿地典型水鸟中的鸻鹬类(Charadriiformes)与雁鸭类(Anseriformes),采用空间多样性指数、人为干扰度等指标研究1980～2010年长江口滩涂湿地景观变化对两类水鸟生境适宜性的影响。结果表明：两类水鸟的不适宜生境、边缘生境、次级生境面积均呈增长趋势,鸻鹬类共增加682 km2,雁鸭类共增加314 km2。而核心生境面积却呈不同的变化趋势,鸻鹬类减少136 km2,雁鸭类增加232 km2,但鸻鹬类和雁鸭类核心生境面积百分比均分别减少566%和194%。1980～2010年鸻鹬类生境适宜性综合评价指数由092下降到053,雁鸭类由089下降到070,鸻鹬类降幅大于雁鸭类。通过定量分析人为干扰度对水鸟生境的影响,发现鸻鹬类对人类干扰更加敏感,中等强度的人类干扰在一定程度上扩大了雁鸭类的适宜生境面积     

鄱阳湖夏候鸟小白鹭对环境样品中重金属的富集研究

通过采集鄱阳湖区北、中、南段小白鹭栖息区域（都昌县多宝乡洞子李村、鄱阳县珠湖乡瓢里山、进贤县前坊镇西湖李家）的环境样品（水样、土壤以及小白鹭食物）与小白鹭羽毛和蛋壳样本,分析其中Pb、Cu、Zn、Cd、V、Cr、Ni和As 8种重金属元素含量,判定鄱阳湖湿地环境中重金属污染状况及生物富集特征。研究表明,环境样品中土壤样品中的重金属含量符合国家Ⅱ类土壤标准,鄱阳湖水样重金属含量在Ⅰ类地表水标准范围之内,仅小白鹭食物（小鱼虾：小河虾、小鲫鱼、小八须鱼等）中的重金属含量高于国家食品标准。小白鹭对环境中重金属污染物的富集表现为：除3个采样点小白鹭羽毛中Cr元素,瓢里山与青岚湖采样点小白鹭蛋壳中Cu元素对其食物的富集系数>1,构成富集外,其他重金属元素均不构成富集,但小白鹭羽毛和蛋壳中的各重金属元素对水样的富集系数为14628～8 00610,富集程度较高。而水体样品中的各重金属在小白鹭食物样品中均存在富集,系数高达51716～14 21937     

Algae mediate submerged macrophyte response to nutrient and dissolved inorganic carbon loading: A mesocosm study on different species

Nutrient and dissolved inorganic carbon are two important factors that influence the development and species composition of submerged macrophyte communities in shallow lake ecosystems. Yet little is known about their potential interactive effects on the submerged macrophytes and competition outcome of macrophyte–phytoplankton. We performed a mesocosm experiment to investigate the growth and photosynthetic performance of three submerged macrophytes in relation to phytoplankton/epiphyton with nutrient and bicarbonate enrichment. During the experimental period (42 d), increase in nutrient loading in water column resulted in a substantial burst of phytoplankton and epiphyton growth and increased light attenuation. When combined with nutrient loading, bicarbonate enrichment also resulted in a heavily phytoplankton- and epiphyton-dominated state, although bicarbonate enrichment per se does not cause the phytoplankton and epiphyton growth. However, increase in nutrient loading in water column had significant negative impact on individual performances (growth and photosynthesis) of the three submerged macrophytes and bicarbonate enrichment increased the effect of eutrophication on two dissected-leaf macrophytes (M. spicatum and E. nuttallii). Furthermore, our results also suggest that species-specific photosynthetic performances occurred when submerged macrophytes in an environment with high abundance of phytoplankton/epiphyton. This study highlighted that increase in nutrient loading and bicarbonate in water column is likely to interactively impact both abiotic and biotic properties of a freshwater ecosystem. The interactions of these two factors could select macrophyte species that are able to resist the shading from phytoplankton/epiphyton, making these species more dominant in natural freshwater ecosystems.     

Haloacetic acid removal by sequential zero-valent iron reduction and biologically active carbon degradation

An innovative haloacetic acid (HAA) removal process was developed. The process consisted of a zero-valent iron (Fe⁰) column followed by a biologically active carbon (BAC) column that were efficient in degrading tri- and di-HAAs, and mono- and di-HAAs, respectively. The merit of the process was demonstrated by its performance in removing trichloroacetic acid (TCAA). An empty bed contact time of 10 min achieved nearly complete removal of 1.2 μM TCAA and its subsequent products, dichloroacetic acid (DCAA) and monochloroacetic acid (MCAA). HAA removal was a result of chemical dehalogenation and biodegradation rather than physical adsorption. Preliminary kinetic analyses were conducted and the pseudo-first-order rate constants were estimated at ambient conditions for Fe⁰ reduction of TCAA and biodegradation of DCAA and MCAA by BAC. This innovative process is highly promising in removing HAAs from drinking water, swimming pool water, and domestic or industrial wastewater.     

虎纹蛙（RANA RUGULOSA）视网膜结构与环境适应性的研究

在光镜和电镜下观察了虎纹蛙（Rana rugulosa)视多膜的组织结构,着重探讨了色素细胞和视细胞的形态结构。视网膜中三个核层及两个网状层分布均匀,无中央凹。色素细胞内含有大量的脂滴、色素颗粒、髓样体和形状各异的溶酶体等。视细胞由视杆细胞和视锥细胞组成,视杆细胞占多数。在视网膜中央区,视杆细胞数与视锥细胞数之比为1：1;在周缘区,两者数量之比为3：1,视杆细胞外段呈高柱状,体积远远大于视锥细胞外段,肌样体内有大量的微管。视锥细胞外段呈矮锥形,椭圆体内有一球状小体。视细胞与节细胞数量之比为3．68：1。结果表明,虎纹蛙视网膜结构特征与其生活于田间、山涧等弱光环境和捕食习性是相适应的。图版1（图1－图10）表2参14     

Rapid determination of ETS markers with a prototype field-portable GC employing a microsensor array detector

The adaptation of a portable gas chromatograph (GC) prototype with several unique design features to the determination of vapor-phase markers of environmental tobacco smoke (ETS) is described. This instrument employs a dual-stage adsorbent preconcentrator, two series-coupled separation columns that can be independently temperature programmed, and a detector consisting of an array of nanoparticle-coated chemiresistors, whose response patterns are used together with retention times for vapor recognition. An adsorbent pre-trap was developed to remove semi-volatile organics from the sample stream. Conditions were established to quantitatively capture two ETS markers, 2,5-dimethylfuran (2,5-DMF) and 4-ethenylpyridine (4-EP, as a surrogate for 3-EP), and to separate them from the 34 most prominent co-contaminants present in ETS using ambient air as the carrier gas. A complete analysis can be performed every 15 min. Projected detection limits are 0.58 and 0.08 ppb for 2,5-DMF and 4-EP, respectively, assuming a 1 L sample volume, which are sufficiently low to determine these markers in typical smoking-permitted environments.