Cr~(3+)胁迫对小球藻生理生化特性的影响

水体重金属污染较难处理,且会对水生物造成严重的影响。为探讨水体中重金属对藻类的毒性影响,以普通小球藻(Chlorella vulgaris)和铬(Cr~(3+))为材料,研究不同浓度Cr~(3+)对普通小球藻生理、生化特性的影响,检测不同浓度的Cr~(3+)对小球藻的毒性效应。结果表明,小球藻的最优生长温度为31℃。此条件下,Cr~(3+)浓度为3 mg·L~(-1)时,小球藻的生物量最大。Cr~(3+)的浓度低于3 mg·L~(-1)时,Cr~(3+)能促进小球藻的生长,且藻细胞中光合色素、蛋白质、可溶性糖、丙二醛(MDA)的含量及超氧化物歧化酶(SOD)的活性也逐渐增加。当各胁迫组的Cr~(3+)浓度超过3 mg·L~(-1)时,随着Cr~(3+)浓度的提高,C.vulgaris的生长受到明显的抑制,藻细胞的光合色素、蛋白质和可溶性糖含量呈现逐渐下降的趋势,而MDA含量持续增加,SOD和脯氨酸则表现出先持续增高后降低(Cr~(3+)浓度为7 mg·L~(-1)时)的趋势。证明不同浓度的Cr~(3+)对小球藻的生理生化特性有不同程度的毒性效应。     

不同钾水平对延胡索幼苗的生理特征和铬吸收影响

为了探讨外源钾(K+)对重金属铬(Cr~(6+))胁迫下延胡索(Corydalis yanhusuo)幼苗的缓解作用,以延胡索块茎为实验材料,采用土培方法,从生理学角度研究不同添加水平外源K+(0~2.78g·kg~(-1))对不同水平Cr~(6+)(0~240mg·kg~(-1))胁迫下延胡索幼苗株高、可溶性糖含量、丙二醛(MDA)含量、超氧化物歧化酶(SOD)活性、过氧化物酶(POD)活性、过氧化氢酶(CAT)活性以及延胡索幼苗地上和地下部分对重金属Cr~(6+)积累的影响。结果表明,(1)在0~60mg·kg~(-1)范围内,Cr~(6+)促进延胡索生长,Cr~(6+)处理水平为60mg·kg~(-1)时株高最大,比对照组(未加Cr~(6+))升高了48.65%;而高处理水平Cr~(6+)(60mg·kg~(-1))抑制延胡索生长。添加不同水平外源钾时,延胡索幼苗株高均比对照组(K0)显著增高,在添加0.67g·kg-1(K2)的外源钾时延胡索株高的增幅达到最大,为26.71%~138.21%。(2)随着Cr~(6+)处理水平的增加,延胡索幼苗中可溶性糖含量和CAT活性先增加后下降,MDA含量和POD活性不断增加,SOD活性不断减少。添加不同水平外源钾,与对照组(K0)相比,延胡索幼苗中可溶性糖含量和SOD、POD和CAT活性显著增加,MDA含量显著减少,特别是添加0.67g·kg~(-1)外源钾(K2)时这种显著性最为明显,分别为对照组(K0)的55.24%~180.77%、13.08%~47.39%、8.22%~115.49%、12.73%~89.00%和13.33%~50.44%。(3)延胡索幼苗体内Cr~(6+)积累随Cr~(6+)处理水平增加而增加,且地下部分Cr~(6+)累积大于地上部分,添加外源钾能抑制延胡索对Cr~(6+)的累积,当钾添加量为0.67g·kg~(-1)(K2)时,与对照组(K0)相比,延胡索体内Cr~(6+)的积累量降低了25.26%~50.71%。此外,外源钾对Cr~(6+)从延胡索地下部分向地上部分转移有一定的促进作用。     

超声预处理对剩余污泥微生物燃料电池性能的影响

为了实现剩余污泥资源化,本实验采用了超声波破壁的预处理方式,构建了以剩余污泥破壁处理混合液为阳极液和以KMn O4溶液为阴极液的序批式双室微生物燃料电池(Microbial Fuel Cells,MFC).将MFC的输出功率密度和COD去除速率作为电池性能的考察指标,研究了超声预处理和投加污泥量对MFC性能的影响.结果表明,随着对投加污泥预处理比(超声预处理污泥量占投加污泥量的比例)和投加污泥浓度的上升,MFC的输出功率密度和COD去除速率也随之上升,在100%污泥预处理比下输出功率密度峰值为296 m W·m-2(Rext=1000Ω);平均COD去除速率为90 mg·L-1·d-1.在投加污泥浓度为8000 mg·L-1时,输出功率密度峰值为476 m W·m-2(Rext=1000Ω);平均COD去除速率为100 mg·L-1·d-1.由实验结果分析,采用超声波破壁预处理高浓度的剩余污泥作为燃料搭建MFC,可提高微生物燃料电池的产电性能和COD去除速率.     

Cd~(2+)和Cr~(3+)对崇明东滩湿地土壤碱性磷酸酶的低剂量兴奋效应

为了明确Cd~(2+)、Cr~(3+)与碱性磷酸酶(ALP)活性之间的低剂量兴奋效应关系,以崇明东滩湿地土壤为对象,通过添加不同剂量的外源Cd~(2+)(Cd Cl2)和Cr~(3+)(Cr Cl3),使土壤中w(Cd~(2+))分别为0、0.001、0.01、0.1、1、5、10、20、100和500 mg·kg-1,w(Cr~(3+))为0、0.5、5、50、100、500和5 000 mg·kg-1,观测土壤ALP活性随时间(0、6、12、24、48、72和120 h)的变化特征。结果表明:(1)培养12 h后,Cd~(2+)添加量为1 mg·kg-1时,ALP活性比对照高8.6%(P0.05);当Cd~(2+)添加量大于10 mg·kg-1时,酶活性受到明显抑制。Cr~(3+)添加量为5 mg·kg-1时,ALP活性比对照显著升高22.8%(P0.05);当Cr~(3+)添加量大于100 mg·kg-1时,酶活性显著降低。这表明Cd~(2+)和Cr~(3+)与ALP之间存在典型的低剂量兴奋效应,但效应的表达与两者接触时间的长短密切相关。(2)以培养24 h的土壤样品为例,Cd~(2+)添加量为1和5 mg·kg-1时,ALP的催化效率(Vmax/Km),即最大反应速率(Vmax)与Michaelis常数(Km)的比值为1.7;当Cd~(2+)添加量增加到20 mg·kg-1时,Vmax/Km比降至0.8,而Vmax和Km的值均低于对照。Cr~(3+)添加量为0.5和5 mg·kg-1时,Vmax/Km比为1.7;当Cr~(3+)添加量增至100 mg·kg-1时,Vmax/Km比降为1.4,但Vmax和Km值均高于对照,这表明重金属与土壤酶之间的低剂量兴奋效应机理可能与其离子特性密切相关。     

多壁碳纳米管与镉复合污染对水稻生长的影响

选取水稻(Oryza sativa)为研究对象,采用营养液水培法,以营养液(0 mg·L~(-1) MWCNTs、0 mg·L~(-1) Cd~(2+))为参照,分析不同浓度梯度下多壁碳纳米管(MWCNTs)单一处理、MWCNTs与Cd~(2+)复合处理对水稻生长的影响.结果表明,MWCNTs单一处理中,水稻幼苗的生长与MWCNTs添加浓度呈明显负相关.低浓度的MWCNTs(1.5 mg·L~(-1))对水稻幼苗的生长产生抑制作用,较高浓度的MWCNTs(≥6.0 mg·L~(-1))会显著(P0.05)抑制水稻幼苗的生长.添加5 mg·L~(-1) Cd~(2+)会增强MWCNTs对水稻幼苗的生长抑制,当MWCNTs浓度从1.5 mg·L~(-1)上升到12 mg·L~(-1),单一处理组与复合处理组相比,水稻幼苗的根系活力分别下降6.4%、10.4%、24.4%和13.9%;水稻幼苗的叶绿素含量显著降低;复合处理组的水稻叶片的POD活性略高于单一处理组,分别高出11.0%、46.1%、5.6%、11.6%;水稻幼苗叶片气孔导度变小、胞间CO_2浓度升高、光合速率减慢.MWCNTs与Cd~(2+)对水稻幼苗的生长具有明显的协同抑制效应.     

Zn2+对SBR污水处理系统中污泥活性的影响

针对不同质量浓度重金属对污泥活性的影响问题,采用模拟SBR反应器研究了不同质量浓度的Zn2+对活性污泥污水处理系统的影响.结果表明,Zn2+对SBR污水处理系统处理效果的抑制作用随着质量浓度的增加而增强.Zn2+投加的质量浓度为20 mg·L-1时,Zn2+对有机物和氨氮的去除没有明显的影响;当Zn2+质量浓度为40 mg·L-1时,Zn2+对活性污泥的抑制作用在实验前期表现明显,后期不显著;当Zn2+质量浓度为80 mg·L-1时,对系统中污泥的活性抑制明显,对CODCr和NH4+-N去除率的抑制率分别达到27.8%和49.4%.此外,研究结果也表明,活性污泥对Zn2+冲击作用具有一定的自适应能力,且在低于40 mg·L-1时硝化菌的适应调整能力较降解COD好氧菌群强.     

低氨氮垃圾渗滤液中有机污染物厌氧氨氧化处理

采用上流式厌氧污泥床处理某垃圾填埋场渗滤液.实验结果表明,在厌氧氨氧化活性稳定后,反应器对氨氮、亚硝氮具有较好的处理效果,氨氮和亚硝氮的平均去除率分别达到98.42%和99.01%,相应的平均容积去除负荷分别为93.64 mg·l-1·d-1和127.57 mg·l-1·d-1,COD的平均去除率为23.51%,平均容积去除负荷为84.53 mg·l-1·d-1.通过GC-MS总共检测出48种主要有机污染物,其中14种有机物的去除率为100%,2种有机物的去除率介于90%和100%之间,7种有机物的去除率介于50%和90%之间,此外还有13种有机物去除率低于50%,反应中亚硝氮和氨氮的去除率比值为1.37,反应器中存在厌氧氨氧化和反硝化的协同作用.     

煅烧的ZnWO4催化超声降解藏红T

本文使用水热合成法制备了ZnWO_4并进行了高温煅烧,以藏红T(BR2)为降解对象考察了煅烧后ZnWO_4催化超声降解有机污染物的活性.结果表明,当煅烧温度为673 K时,ZnWO_4具有更好的催化超声降解活性.ZnWO_4催化超声降解BR2的主要作用机制是产生的活性氧(ROS)如·OH和·O~-_2以及空穴(h~+)的氧化作用.当煅烧后ZnWO_4的加入量为1.5 g·L~(-1)、BR2初始浓度为10 mg·L~(-1)、溶液起始pH值为7、超声功率为200 W、超声时间为120 min、温度为25±0.1℃时,BR2的降解率为90.23%±0.93%.研究结果表明,煅烧可显著提升ZnWO_4催化超声降解有机污染物的活性,将为其进一步应用提供研究基础.     

生物硫铁复合材料对Cr(VI)污染水体中斑马鱼的保护作用

目前铬污染已经成为世界性的环境问题.为探究生物硫铁复合材料(生物硫铁,BISC)在Cr~(6+)污染水体中对鱼类的保护作用,以斑马鱼为实验载体,在测定Cr~(6+)对斑马鱼的半数致死浓度(LC50)的基础上,研究生物硫铁对Cr~(6+)污染水体的处理效果,以及生物硫铁投加比(生物硫铁与Cr~(6+)的摩尔浓度之比)、投加时间和水体p H对Cr~(6+)污染水体中斑马鱼保护作用的影响.结果显示,在79.30 mg/L(24 h-LC50)Cr~(6+)污染水体(p H=6.98)中,生物硫铁的投加能够快速降低水体Cr~(6+)的浓度.当生物硫铁投加比达到3时能将Cr~(6+)快速去除,15 min后Cr~(6+)去除率达到84.01%,96 h后达到99.99%.斑马鱼存活率随生物硫铁投加比的增加和投加时间的减少而增大,最佳投加比为0.5;最佳投加时间为0-4 h,此时能将斑马鱼存活率提高90%以上,24 h时投加,作用96 h后亦可使斑马鱼存活率提高约3倍.在p H 6-9内,生物硫铁的投加可显著提高斑马鱼的存活率,且对斑马鱼的保护作用随p H降低而逐渐增强.本研究表明生物硫铁对Cr~(6+)污染水体中的斑马鱼保护效果显著,在Cr~(6+)突发污染治理方面具有广阔的应用前景.     

珠江口广州海域COD与DO的分布特征及影响因素

于2003-2007年2月(冬季)、5月(春季)、8月(夏季)、10月(秋季)调查了广州海域16个站位的COD、DO以及其它理化因子的时空分布特征.调查期间,COD质量浓度范围为0.76～9.12 mg·L~(-1),平均值为2.83 mg·L~(-1);溶解氧质量浓度范围为1.98～9.79 mg·L~(-1),平均值为5.27 mg·L~(-1).结果表明,COD与DO的时空分布特征主要受生活污水排放,陆源排污,降雨量以及水动力状况等因素的影响.COD质量浓度在冬季和秋季较高,春季和夏季较低,而DO质量浓度则是冬季和春季高于秋季和夏季.空间分布上,COD质量浓度从湾内向湾外逐步递减,而DO变化趋势则相反,湾内站位在夏季出现缺氧区.相关性分析中,COD质最浓度与氮营养盐及Chl-a显著正相关,而DO则与COD、Chl-a、Ph以及石油烃显著负相关.COD与DO分布特征对于河口地区的赤潮及碳循环研究有一定研究价值.     

Enhancement of activated sludge performance on ammonium removal by clinoptilolite

This study evaluated the influence of clinoptilolite on the performance of activated sludge system shocked by high concentration of ammonium. The ammonium and chemical oxygen demand (COD) removal from the experimental reactor containing clinoptilolite and from the clinoptilolite-free control reactor was determined. The ammonium and COD removal was approximately 8 and 20% higher in the experimental reactor than in the control reactor, respectively. The removal increased with an increase in clinoptilolite concentration over the tested range up to 50?mg?L^?1. The presence of clinoptilolite resulted in the sludge flocs being more compacted with smoother surfaces and edges. Molecular biological analysis revealed that clinoptilolite increased the DNA diversity, richness, and evenness of sludge microbes. The enhanced-performance activated sludge previously treated with clinoptilolite was less influenced by the shock of ammonium than non-treated sludge in terms of the ammonium and COD removal. These results suggest that clinoptilolite enhanced the performance of activated sludge system in the removal of ammonium and COD. Amendment of activated sludge with natural zeolites may thus improve the efficiency of wastewater treatment.     

Effect of iron addition on the performance of anoxic-oxic membrane process and biological phosphorus removal北大核心CSCD

In order to solve the problem of poor treatment of phosphorus in membrane bioreactor (MBR) with long sludge retention time (SRT), a ferric salt was added to enhance phosphorus removal; FeCl36H2O (Fe/P = 2.0) was added to the reactor. The removal efficiency of nitrogen, organic matters, and phosphorus in the MBR was investigated systematically. Moreover, this study focused on the membrane performance, the change of active sludge flora, and the effect of adding a ferric salt on membrane fouling before and after the addition. It was seen that adding the ferric salt could not affect the removal of COD and NH4 +-N and the removal rate of COD and NH4 +-N reached over 90%. However, the average removal rate of phosphorus was 52%, while the removal rate increased by nearly 40% after adding the ferric salt. The effects of adding ferric salts on the dominant bacteria and biological phosphorus removal of activated sludge were further studied. The results showed that the addition of ferric salt (Fe/P = 2.0) decreased the diversity of active sludge flora and relative abundance of some phosphorusaccumulating organisms and had a negative effect on biological phosphorus removal. The analysis of transmembrane pressure difference (TMP) recording revealed that the concentration of iron salts did not exacerbate membrane fouling. The results showed that the concentration of iron salts entering the membrane bioreactor would reduce the relative abundance and phosphorus removal efficiency of the activated sludge in the system to a certain extent, but it had no obvious effect on membrane fouling. It allowed the effluent to attain acceptable standards, especially with respect to phosphorus removal efficiency. © 2018 Science Press. All rights reserved.     

AB工艺减少污泥重金属的效果

在AB工艺中,利用A段活性吸附去除重金属从而降低B段污泥中重金属含量,使其达到农用标准（GB4284-84酸性土壤控制标准）。利用小型污水处理实验场,模拟研究了AB工艺A段中重金属的去除情况,对AB运行控制参数进行优化探讨,以使A段能有效去除大部分重金属,并尽可能降低有毒有害污泥产量。结果表明：溶解氧质量浓度控制在0.5mg·L-1,污泥质量浓度调节为约500mg·L-1时,Cu2＋去除率可达87.6%,Zn2＋的去除率为78.7%,Ni2＋去除率为51%。当污泥质量浓度在1000～1500mg·L-1时,A段处理后污泥沉降性能好转,对重金属离子的去除有较好的效果,且不过多截留污水中的有机物。且B段剩余污泥中的Cu2＋、Zn2＋、Ni2＋含量都基本达到酸性土壤污泥农用控制标准。因此,适当控制AB工艺相关参数条件,利用A段活性污泥去除大部分重金属,降低B段产泥中重金属含量,达到农业控制标准是可行的,污泥经处理后进行土地资源化利用可成为我国污泥处置与利用的一种有效途径。     

Effects of Al3+ on pollutant removal and extracellular polymeric substances (EPS) under anaerobic,anoxic and oxic conditions

The highest removal efficiencies of COD and TN were achieved under 10 mg/L of Al³⁺. The highest TP removal efficiency occurred under 30 mg/L of Al³⁺. EPS, PS and PN concentrations increased with the addition of Al³⁺. Sludge properties significantly changed with the addition of Al³⁺. Aluminum ions produced by aluminum mining, electrolytic industry and aluminum-based coagulants can enter wastewater treatment plants and interact with activated sludge. They can subsequently contribute to the removal of suspended solids and affect activated sludge flocculation, as well as nitrogen and phosphorus removal. In this study, the effects of Al³⁺ on pollutant removal, sludge flocculation and the composition and structure of extracellular polymeric substances (EPS) were investigated under anaerobic, anoxic and oxic conditions. Results demonstrated that the highest chemical oxygen demand (COD) and total nitrogen (TN) removal efficiencies were detected for an Al³⁺ concentration of 10 mg/L. In addition, the maximal dehydrogenase activity and sludge flocculation were also observed at this level of Al³⁺. The highest removal efficiency of total phosphorus (TP) was achieved at an Al³⁺ concentration of 30 mg/L. The flocculability of sludge in the anoxic zone was consistently higher than that in the anaerobic and oxic zones. The addition of Al³⁺ promoted the secretion of EPS. Tryptophan-like fluorescence peaks were detected in each EPS layer in the absence of Al³⁺. At the Al³⁺ concentration of 10 mg/L, fulvic acid and tryptophan fluorescence peaks began to appear, while the majority of protein species and the highest microbial activity were also detected. Low Al³⁺ concentrations (<10 mg/L) could promote the removal efficiencies of COD and TN, yet excessive Al³⁺ levels (>10 mg/L) weakened microbial activity. Higher Al³⁺ concentrations (>30 mg/L) also inhibited the release of phosphorus in the anaerobic zone by reacting with PO₄^3-.     

厌氧好氧一体化生物反应器处理发酵废水的研究

采用新型厌氧好氧一体化生物反应器对发酵废水进行了中试处理研究.试验结果表明,系统总有机负荷最高可达到8.88kg(COD)m-3d-1,系统去除率稳定在88.10%~96.88%,说明反应器处理效率高,抗冲击能力强.反应器结构合理,利于保持丰富、高活性的微生物,反应器厌氧区颗粒污泥TS高达83.9gL-1,VS/TS为56.9%~57.4%,比产甲烷活性为280~350mL(CH4)gvss-1d-1;好氧区固定化微生物TS高达64.03gL-1载体,VS/TS为94.02%~94.30%.反应器各功能区对废水的降解过程分析,说明反应器厌氧区和好氧区一体化结构合理,可将废水逐级降解,从而保证整个系统的处理效果.图8表4参11     

竹炭固定床-聚氨酯流化床一体化反应器处理生活污水

为解决剩余污泥问题,研制了产泥率少的片状竹炭固定床-聚氨酯切块流化床一体化反应器,在保证流化床高浓度微生物的同时,维持竹炭固定床的好氧,兼性厌氧,以实现污泥的原位分解.试验采用南京林业大学紫湖溪生活污水,COD为140—170 mg·L-1,TP为1—2 mg·L-1,TN为35—45 mg·L-1,氨氮25—30 mg·L-1,SS为35—40 mg·L-1.反应器在第30 d启动成功.稳定的运行结果显示,水力停留时间为10 h时,反应器对有机物的去除效果较好,出水中COD、TN、TP、氨氮的浓度分别为19 mg·L-1、7 mg·L-1、0.47 mg·L-1、4.5 mg·L-1,去除率达到87%、76%、72%、84%,出水中各指标均满足《城镇污水处理厂污染物排放标准》(GB18918—2002)中的一级B排放标准.经竹炭固定床处理的出水SS浓度很低,长期维持在14 mg·L-1左右,二沉池出水中的SS平均浓度为12.7 mg·L-1,整个反应器对二沉池依赖性较小.     

活性污泥吸附预处理重油裂化制气废水

利用剩余活性污泥对含有高浓度芳香族化合物的重油裂化制气废水进行预处理的研究并提出了合适的吸附条件。结果表明，活性污泥吸附预处理对COD和悬浮物有明显的去除效果，而且可以提高废水BOD5／COD的比值，另外还有降解芳香族化合物的作用，使进入生物处理系统的废水的可生物降解性有明显的改善。这一方法为利用普通废水生物处理系统中产生的剩余活性污泥来预处理难降解的工业废水提供了一条有效的途径。     

序批式生物膜法同步除磷脱氮特性研究

对淹没序批式生物膜法去除有机物和磷及同步部分脱氮的特性进行了研究。其适合的载体装填密度为30％，水力停留时间为9h，其中厌氧3h，好氧6h，进水COD负荷从0．27kg/(m^3.d)到1．32kg/(m^3.d)均可使除磷率达90％以上，脱氮率达50％－60％。淹没式生物膜法除磷脱氮工艺中的优势菌属为假单胞菌属，其次依顺序为气单胞菌属，芽孢杆菌属，微球菌属，硝化矸菌属，生物膜具有生物量大（MLVSS达5531．7mg/L)，脱落污泥含磷量高（达5．67％），沉降性好（SVI为101．7）的特点，污泥产率为0．1996kg干泥／kgCOD。     

Advanced nitrogen and phosphorus removal in A2O-BAF system treating low carbon-to-nitrogen ratio domestic wastewater

A laboratory-scale anaerobic-anoxic-aerobic process (A²O) with a small aerobic zone and a bigger anoxic zone and biologic aerated filter (A²O-BAF) system was operated to treat low carbon-to-nitrogen ratio domestic wastewater. The A²O process was employed mainly for organic matter and phosphorus removal, and for denitrification. The BAF was only used for nitrification which coupled with a settling tank Compared with a conventional A²O process, the suspended activated sludge in this A²O-BAF process contained small quantities of nitrifier, but nitrification overwhelmingly conducted in BAF. So the system successfully avoided the contradiction in sludge retention time (SRT) between nitrifying bacteria and phosphorus accumulating organisms (PAOs). Denitrifying phosphorus accumulating organisms (DPAOs) played an important role in removing up to 91% of phosphorus along with nitrogen, which indicated that the suspended activated sludge process presented a good denitrifying phosphorus removal performance. The average removal efficiency of chemical oxygen demand (COD), total nitrogen (TN), total phosphorus (TP), and NH ₄ ⁺ -N were 85.56%, 92.07%, 81.24% and 98.7% respectively. The effluent quality consistently satisfied the national first level A effluent discharge standard of China. The average sludge volume index (SVI) was 85.4 mL·g^?1 additionally, the volume ratio of anaerobic, anoxic and aerobic zone in A²O process was also investigated, and the results demonstrated that the optimum value was 1:6:2.     

Simultaneous nitrification and denitrification in activated sludge system under low oxygen concentration

Simultaneous nitrification and denitrification (SND), which is more economical compared with the traditional method for nitrogen removal, is studied in this paper. In order to find the suitable conditions of this process, a mixed flow activated sludge system under low oxygen concentration is investigated, and some key control parameters are examined for nitrogen removal from synthetic wastewater. The results show that SND is accessible when oxygen concentration is 0.3–0.8 mg/L. The nitrogen removal rate can be obtained up to 66.7% with solids retention time (SRT) of 45 d, C/N value of 10, and F/M ratio of 0.1 g COD/(g MLSS·d). Theoretical analysis indicates that SND is a physical phenomenon and governed by oxygen diffusion in flocs.