含锌重金属废水藻类吸附处理技术

以小球藻为吸附剂,研究藻类吸附剂对重金属废水中Zn2+的吸附过程,分析吸附时间、温度、pH值、Zn2+起始浓度以及预处理过程等因素对小球藻吸附Zn2+性能的影响。结果表明:预处理能提高小球藻的吸附性能,其吸附过程符合Langmuir吸附特征,对废水的pH值适应范围广。对于ρ(Zn2+)=100 mg/L的重金属废水经小球藻一次处理,去除率达到98%。小球藻吸附处理废水中Zn2+的较佳工艺条件为pH值6.5、温度25℃、吸附时间60 min、小球藻用量2 g/L。     

喹诺酮类和磺胺类抗生素对绿藻生长的影响

喹诺酮类抗生素(氧氟沙星,OFLX)和磺胺类抗生素(磺胺间甲氧嘧啶,SMM;磺胺二甲基嘧啶,SMZ)是目前自然水体中含量较高的两类抗生素,研究其对水环境的生态效益意义重大。采用单因素方法分析绿藻对不同浓度抗生素的敏感性,同时定量分析3种抗生素在单一及联合作用下对绿藻生长的半抑制浓度。结果表明:单一及联合抗生素对淡水绿藻均表现为"低促高抑",抗生素浓度≤5μg/mL促进藻类的生长,5μg/mL抑制藻类的生长;OFLX、SMM、SMZ对普通小球藻的半抑制浓度分别为:7.96、6.58、8.19μg/mL;对斜生栅藻的半抑制浓度分别为:6.20、7.20、9.89μg/mL;OFLX+SMM对普通小球藻的半抑制浓度为8.28μg/mL,对斜生栅藻的半抑制浓度为5.71μg/mL;OFLX+SMM+SMZ对普通小球藻的半抑制浓度为10.23μg/mL,对斜生栅藻的半抑制浓度为7.40μg/mL。抗生素对淡水绿藻的生长表现为"低促高抑",OFLX和联合抗生素对斜生栅藻敏感,SMM、SMZ对普通小球藻更为敏感。     

周丛藻类对景观水体水质净化的效果研究

采用水体中自然生长的周丛藻类,在近自然条件下,研究周丛藻类对景观水体的净化能力。结果表明,周丛藻类对NH4+-N、TN、TP、TSS(总悬浮物)和Chla(叶绿素a)的平均去除率分别为45.2%、26.9%、25.9%、50%和41%;同时,周丛藻类系统的出水DO质量浓度平均增加5.0 mg/L,pH值平均提高0.5个单位,而空白系统的出水DO质量浓度和pH值没有明显变化。回归分析结果显示,周丛藻类对NH4+-N、TN的最高去除率出现在负荷率分别为0.87 mg/(g.d)(88.9%)和0.40 mg/(g.d)(53.3%)时。试验期间,周丛藻类的生物量增加了52.4%,藻类群落从颗粒态硅藻、绿藻为主的藻群演替为以丝状和颗粒态蓝藻和绿藻为主的群落。     

蛋白核小球藻对4种重金属胁迫的响应研究

为了利用藻类对水体重金属进行监测预警,以蛋白核小球藻为指示生物,研究了重金属Cd~(2+)、Cr~(6+)、Mn~(2+)、Pb~(2+)对藻类的抑制作用。实验结果表明:重金属对蛋白核小球藻的抑制作用总体表现为随着重金属浓度的增加和胁迫时间的延长而增加,抑制率一般在0~48 h内迅速增加,随后增长速率有所减缓,至96 h抑制率达到最大。蛋白核小球藻的抑制率与重金属浓度呈现明显的剂量-效应关系;与吸光度、叶绿素相对含量的变化相比,F_v/F_m对重金属胁迫的响应变化最为稳定和敏感,因此更适合作为检测指标监测重金属。从EC_(50)值的比较看,Cd~(2+)对蛋白核小球藻的毒性最大,其次是Cr~(6+)和Pb~(2+),Mn~(2+)的毒性最小。     

再生水回用中氮磷对两种典型水华藻类生长影响研究

根据相关标准,试验选取了不同的氮磷浓度值,对蓝藻水华常见的铜绿微囊藻和绿藻水华常见的小球藻分别进行了单独培养以及两者的竞争试验.结果表明,铜绿微囊藻生长的最适氮磷浓度分别为15 mg/L、0.3～0.5 mg/L,小球藻生长的最适氮磷浓度分别为15 mg/L、0.1～0.5 mg/L;在氮磷比为15、30、50、150的试验条件下,竞争试验中的优势藻均为小球藻.建议以再生水为补水水源的景观水体中,再生水的氮磷浓度分别控制为:总氮≥15 mg/L、磷≤0.1 mg/L、氮磷比为150以上,能有效地抑制铜绿微囊藻生长.     

镧对黄河包头段水体中混合藻类的影响

选取黄河水体中含量较多的稀土元素镧(La)作为研究对象,以引黄水库富营养化水体中的混合藻类为受试生物,进行藻类的培养试验,探讨了稀土元素对黄河水体中混合藻类生长生理的影响规律。结果表明:低浓度(2 mg/L)La对藻类的生长具有刺激作用;高浓度(50 mg/L)La对藻类的生长具有抑制作用,且浓度越高抑制作用越强;中等浓度(5～10 mg/L)La对藻类生长的刺激与抑制作用受光照强度影响;La在任何浓度下都会改变藻类种群结构、抑制水体中藻类的生物多样性,且浓度越高,抑制作用越强;引黄水库每年3月份藻类的爆发及黄河水体的富营养化可能与水体中的La有关。     

再生水补水的景观水体优势藻种水华爆发阈值条件的确定

再生水景观补水是污水再生利用的重要途径,但水华频发是其利用的主要制约因素。以从典型再生水补水的景观水体中识别出的3种优势藻种为研究对象,采用室内静态实验方法研究了在温度、光照强度和营养盐浓度共同作用下的优势藻种的生长状况。结果表明：在温度T=30 ℃、照度=9 000 lx、N/P较低的再生水补水水体中,水华微囊藻更易成为优势藻种,仅培养3 d,藻密度就由1.0×10⁴ cell/mL增加到9.1×10⁴ cell/mL,接近水华爆发的阈值条件（大于10×10⁴ cell/mL）;普通小球藻和四尾栅藻较适合在T=25 ℃、光照强度分别为5 000和7 000 lx、N/P相对较高的再生水原水中生长,培养5 d可达到或接近水华爆发阈值条件。降低再生水体中的磷浓度可在一定程度上抑制藻类的生长,当再生水补水水体中TP浓度从0.3 mg/L降低到 0.1 mg/L时,对普通小球藻和四尾栅藻的抑制率分别为56.6%和40.7%,但对水华微囊藻的抑制作用相对较弱。研究结果揭示了再生水景观补水水体中藻类的生长规律,为控制藻华爆发提供了一定的理论依据。     

不同价态铁对四尾栅藻生长的影响及机理探讨

采用实验室模拟培养的方法,分别培养初始Fe2+和Fe3+为0.2 mg/L、0.4 mg/L、0.5mg/L、0.7mg/L时的四尾栅藻。结果表明:四尾栅藻对于铁的吸收利用主要包括蛋白转运和铁置换两个过程,对于Fe2+的吸收利用以蛋白转运为主,通过修正Shaked铁吸收模型,蛋白转运进一步分为Fe3+还原和Fe2+转运两个步骤。铁的不同价态对四尾栅藻的生长影响差异明显,Fe2+较之Fe3+表现出更强的藻利用时效,同样的游离态浓度下,藻增殖速度快,藻峰值更高。四尾栅藻倾向于优先吸收Fe2+。四尾栅藻的生长环境存在一个最佳的Fe2+浓度范围,在初始Fe2+为0.4mg/L条件下,四尾栅藻生长速率最快,藻峰值最大,分别达到0.136 7个/(L·d)和2.9×108个/L。当Fe2+大于0.4mg/L时,抑制作用不明显,但增殖速率有所减缓。营养充足条件下,四尾栅藻生长曲线满足y=Aln(x)+B,A、B系数随着初始Fe2+浓度的不同而不同。     

高盐景观水体除磷、除藻药剂优选及复配

淡水盐碱化是全球范围内面临的一个新兴环境问题,其中城镇内人工景观水体表现尤为突出。高盐景观水体盐度大,导致植物不易生长,藻类逐渐成为优势种群,影响观感。通过絮凝法同时除磷、除藻,使景观水体恢复藻类爆发前的状态。研究11种絮凝药剂对TP、Chla(叶绿素a)的去除效率,其中PAC除磷效果很好,CPAM可以有效除藻。经过浓度梯度优选实验,优选出PAC和CPAM的最优投加浓度,并进行复配试验。复配结果为当PAC投加浓度10mg/L、CPAM投加浓度3mg/L时组合除磷、除藻效果最佳,TP平均去除率为92.52%,Chla平均去除率为98.32%。     

Fe、Mn、Zn对湖泊藻华暴发影响规律研究

通过设计正交组合试验,研究3种典型金属元素Fe、Mn、Zn,结合代表性常量元素P,考查对淡水藻类生长的影响。结果表明:当P为0.04～0.32mg/L时,藻生物产量随着P的增加而增加。当Fe0.05mg/L时,促进藻类生长;Fe0.1mg/L时,抑制藻类生长。Zn0.01mg/L时促进藻类生长,Zn0.04mg/L时,抑制藻类生长。Mn本身没有表现出规律性影响趋势,但与微量元素之间的竞争性抑制有密切关系。藻生长速率分别在P0.16mg/L,Fe0.05mg/L,Mn0.05mg/L,Zn0.01mg/L时最大,藻生物产量分别在P0.32mg/L,Fe0.1mg/L,Mn0.05mg/L,Zn0.01mg/L时最高。四种物质对藻生长速率影响的显著顺序依次为:ZnPFeMn。     

SBR活性污泥吸附水中重金属离子的研究

研究了SBR活性污泥对重金属离子(Cu2+、Zn2+、Mn2+、Fe3+)的吸附作用。结果表明:在30℃温度下,pH为5时,其对Cu2+、Zn2+、Mn2+的去除率达到最大值50%左右;当pH为3时,对Fe3+的去除率达到最大值73.6%。吸附动力学过程可用二级吸附速率方程描述。在10~30℃温度范围内,随着温度的升高,Cu2+、Zn2+、Mn2+、Fe3+的去除率分别由54.6%、46.3%、45.3%6、8.9%,增大到58.6%、51.3%、49.6%、73.6%。当重金属离子初始质量浓度为50 mg/L,污泥投加量为0.2 g时,Cu2+、Zn2+、Mn2+和Fe3+的去除率达到最大值,分别为61.5%、54.3%、53.3%和76.2%。吸附等温线结果表明,Cu2+、Zn2+、Mn2+、Fe3+在吸附剂上的吸附可用Freundlich方程描述。     

锌离子对菖蒲的胁迫反应研究

采用水培法,以Hoagland溶液为基础培养液,研究Zn2+胁迫对菖蒲幼苗生长状况、细胞渗透性、过氧化物酶(POD)活性、超氧化物歧化酶(SOD)活性、叶绿素以及脯氨酸质量比的影响。结果表明,Zn2+胁迫下菖蒲幼苗生长受到严重影响;随着Zn2+质量比的增加,叶片电导率不断增大;POD、SOD活性均高于对照,并且呈现先升高后降低的正相关趋势;叶绿素的质量比显著降低,与Zn2+质量比呈负相关趋势;脯氨酸质量比则一直呈上升的变化趋势。研究结果说明,酶活性的升高是由于菖蒲对Zn2+胁迫做出的应激反应,而高质量比Zn2+却对菖蒲的保护酶活性有抑制作用。     

耐辐射球菌对Cu2+的去除效率

耐辐射球菌是一种非致病菌,拥有极强的抗辐射、抗氧化特性,具有成为工程菌处理Cu2＋的潜力。采用酶标仪测定Cu2＋对耐辐射球菌的生长速度的影响,用电感耦合等离子光谱法测定菌液离心后得到的上清液Cu2＋浓度。结果表明,当Cu2＋初始质量浓度为1．36mg／L时,耐辐射球菌对其清除效率为57．3％;当-Cu2＋初始质量浓度为6．28mg／L时,对其清除效率为35．4％。此外,用激光共聚焦显微镜观察受到Cu2＋胁迫的耐辐射球菌,发现球菌具有明显的聚集效应。     

邻苯二酚和邻苯三酚对藻类化感作用的试验

以藻类细胞的叶绿素a含量变化为指标来分析不同浓度的邻苯二酚和邻苯三酚对蛋白核小球藻以及斜生栅藻生长代谢的化感作用程度,初步确定了邻苯二酚(O-Dihydroxybenzene)和邻苯三酚(Pyrogallol)对两种藻类生长抑制程度最高的投加量,为筛选高效抑藻化感物质及其最佳作用浓度提供了试验依据.     

Plant algae method for arsenic removal from arsenic contaminated groundwater

Field studies were carried out in Urumqi River Basin in Northwest China. The study focused on experimentation on a plant algae method that was tested by taking various water chemistries into consideration. The results from a greenhouse experiment evaluated for four doses of P (0, 100, 200, and 300 μmol/L) using two ferns (30 and 60 day old) on 15 L of contaminated groundwater per plant revealed that the biomass of 30-day old ferns gained was higher than 60-day fern. As solution-P increased from 0 to 450 μmol/L, Phosphorus concentration in the fronds increased from 1.9 to 3.9 mg/kg and 1.95 to 4.0 mg/kg for 30-d and 60-d ferns respectively. This study showed that the plant algae method may be a good solution to maximize arsenic uptake in the short term under normal climatic conditions.     

Particle size distribution and property of bacteria attached to carbon fines in drinking water treatment

The quantitative change and size distribution of particles in the effluents from a sand filter and a granular activated carbon （GAC） filter in a drinking water treatment plant were investigated. The average total concentration of particles in the sand filter effluent during a filter cycle was 148 particles/mL, 27 of which were larger than 2 μm in size. The concentration in the GAC effluent （561 particles/mL） was significantly greater than that in the sand filter effluent. The concentration of particles larger than 2 μm in the GAC filter effluent reached 201 particles/mL, with the amount of particles with sizes between 2 μm and 15 μm increasing. The most probable number （MPN） of carbon fines reached 43 unit/L after six hours and fines between 0.45 μm and 8.0 μm accounted for more than 50%. The total concentration of outflowing bacteria in the GAC filter effluent, 350 CFU （colony-forming units） /mL, was greater than that in the sand filter effluent, 210 CFU/mL. The desorbed bacteria concentration reached an average of 310 CFU/mg fines. The disinfection efficiency of desorbed bacteria was lower than 40% with 1.5 mg/L of chlorine. The disinfection effect showed that the inactivation rate with 2.0 mg/L of chloramine （90%） was higher than that with chlorine （70%）. Experimental results indicated that the high particle concentration in raw water and sedimentation effluent led to high levels of outflowing particles in the sand filter effluent. The activated carbon fines in the effluent accounted for a small proportion of the total particle amount, but the existing bacteria attached to carbon fines may influence the drinking water safety. The disinfection efficiency of desorbed bacteria was lower than that of free bacteria with chlorine, and the disinfection effect on bacteria attached to carbon fines with chloramine was better than that with only chlorine.     

镉在次级河流底泥中吸附—解吸特性及其风险评估

采用吸附解吸试验研究河流底泥对Cd2+的吸附解吸特征,评估Cd2+在底泥中的迁移性及其环境风险。结果表明:河流底泥对Cd2+的吸附质量比随Cd2+平衡质量浓度的增高而增大,Cd2+平衡质量浓度为23.09μg/mL时,底泥的最大吸附质量比为1 655.575μg/g;吸附率随Cd2+平衡质量浓度的增大而减小。底泥对Cd2+的吸附可以分为30 min前的快速吸附和60 min后的慢速吸附阶段。底泥对Cd2+的解吸质量比随吸附质量比的增高而增大,解吸率保持在1.51%~4.96%之间。保留因子R′对Cd2+平衡质量浓度的变化较敏感,随着Cd2+平衡质量浓度上升而下降。大溪河水体中Cd2+的实际分配系数Kd和保留因子R′分别为1 766.15 L/kg,99 968.76 L/kg,表明Cd2+在环境中迁移的风险较低。     

The effect of oxidants on 2-MIB concentration with the presence of cyanobacteria.

In this study, the effect of three oxidants, sodium hypochlorite, potassium permanganate, and ozone, were tested for the removal of 2-MIB with presence of cyanobacteria. Algae in water samples from the source water of Feng-Shen waterworks (FSW), Taiwan were cultivated at 30 degrees C with continuous light at an intensity between 2,500 and 3,400 lux. During the cultivating process, water samples were analyzed for nutrients, light absorbance at 665 nm (A665), and 2-MIB concentration. The 2-MIB concentrations within the incubated samples increased to as high as 1,000 ng/L to 2,000 ng/L, although no extra nutrients were added to the raw water. After 2 to 3 days incubation, the intracellular 2-MIB concentration was as high as 70% of the total 2-MIB in the samples. The algae that developed were mainly cyanobateria, and more than 90% belonged to the Genus Oscillatorias. An almost 100% removal of both 2-MIB and geosmin in the raw water was observed after ozonation for 10 minutes at a dosing rate of 0.91 mg/l-min. Chlorine and permanganate were much less effective, both removing only about 11% of the 2-MIB within 60 minutes at oxidant concentration of 10 mg/l. Oxidation of the cultivated samples showed that chlorine and permanganate may damage algae cells causing them to release intracellular 2-MIB. During the 60 minutes of reaction time, the total 2-MIB concentrations (intracellular plus dissolved) varied by no more than 10%, however, the ratios between dissolved and total 2-MIB concentrations increased. Two effects of ozonation on the 2-MIB concentration in the cultivated samples were observed when the algae were young, namely 2-MIB release from damaged cells and 2-MIB oxidization. The rates of 2-MIB release and 2-MIB destruction were similar. However, old algae cells were more easily damaged. As a result, intracellular 2-MIB was released faster, and the soluble 2-MIB was destroyed more quickly by ozonation.