一株产絮酵母菌废菌体对Cd2+的吸附特性

将一株产絮酵母菌(编号B-02号)发酵后的废菌体制成生物吸附剂,研究该生物吸附剂对废水中Cd2+的生物吸附特性。结果表明:(1)pH值对Cd2+会产生较大的影响,偏酸性(pH=4～6)条件利于吸附;该吸附剂对Cd2+吸附速率较快,8～10 min就可达到吸附平衡;(2)吸附剂的吸附动力学符合二级动力学模型,吸附Cd2+的实验数据对Langmuir等温式的拟合情况良好,吸附剂吸附Cd2+的最大吸附量为70.752 mg/g。用0.5 mol/L HNO3对吸附Cd2+的酵母菌进行解吸,解吸率可达89.7%。     

Effect of microbial siderophore DFO-B on Cd accumulation by Thlaspi caerulescens hyperaccumulator in the presence of zeolite

Hyperaccumulators are grown in contaminated soil and water in order that contaminants are taken up and accumulated. Transport of metals from soil to plant is initially dependent on the solubility and mobility of metals in soil solution which is controlled by soil and metal properties and plant physiology. Complexation with organic and inorganic ligands may increase mobility and availability of metals for plants. In this work the influence of desferrioxamine-B (DFO-B), which naturally is produced in the rhizosphere, and zeolite on Cd accumulation in root and shoot of Thlaspi caerulescens (Cd hyperaccumulator) was investigated. Plants were grown in pots with clean quartz sand, amended with 1% zeolite; treatment solutions included 0, 10, and 100 μM Cd and 70 μM DFO-B. Addition of zeolite to the quartz sand significantly reduced Cd concentration in plant tissues and translocation from root to shoot. On contrary, DFO-B considerably enhanced Cd sorption by roots and translocation to aerial part of plants. Treating the plants with zeolite and DFO-B together at 10 μM Cd resulted in reduction of the bioaccumulation factor but enhancement of Cd translocation from root to shoot at the rate of 13%. In contrast, at 100 μM Cd in the solution both bioaccumulation and translocation factors decreased. Total metal accumulation as a key factor for evaluating the efficiency of phytoremediation was highly influenced by treatments. Presence of zeolite in pots significantly decreased total Cd accumulation by plants, whereas, DFO-B clearly enhanced it.     

无机-有机高分子复合絮凝剂处理含油废水的试验研究

研究了用聚合氯化铝（PAC）、聚合硫酸铁（PFS）、聚丙烯酰胺（PAM）及改性蒙托石等不同无机—有机高分子絮凝剂复配使用处理炼钢厂连铸含油废水的除油效果,考察了不同絮凝剂的复配以及絮凝剂的不同复配比例对处理效果的影响。试验结果表明,用聚合氯化铝（PAC）＋聚合硫酸铁（PFS）＋聚丙烯酰胺（PAM）3种絮凝剂复配使用除油效果最佳,当3种絮凝剂的复配比为2∶2∶3时除油效果最好,除油率达到88.2%,达到国家排放标准。     

基于剩余污泥的超声法提取微生物絮凝剂

通过超声系列实验,对超声法从剩余污泥中提取微生物絮凝剂(MBF)进行了系统研究。从剩余污泥中提取的MBF在碱性条件下表现出较好的絮凝活性。提高污泥浓度有利于提取出较高絮凝活性的MBF。由于超声波的破解作用,超声频率或功率过高均不利于MBF的提取。在20 kHz的超声频率下,连续超声比脉冲为1、4或8 s超声时的提取效果均要好。经过工艺优化,采用20 kHz、120 W的超声波对剩余污泥(19.4 g/L)连续超声30 s,所提取的MBF对高岭土悬浊液的絮凝率接近70%。结果表明,超声法可用于从剩余污泥中直接提取MBF,在降低MBF生产成本的同时实现污泥的资源化利用。     

简单芽孢杆菌产高效微生物絮凝剂

通过从绿化植物根际土壤和污水处理厂的活性污泥中分离筛选絮凝剂产生菌,得到一株稳定高效的微生物絮凝剂产生菌PS1,根据形态学特征、生理生化实验以及16S rDNA序列分析将其鉴定为简单芽孢杆菌(Bacillus simplex)。对菌株PS1产生絮凝剂的最佳培养时间、絮凝活性分布以及pH、CaCl2、絮凝剂投量对絮凝效果的影响进行了研究,并考察了其对实际废水的絮凝效果。结果表明,菌株PS1产絮凝剂的最佳培养时间为36 h,产生的絮凝活性物质全部存在于发酵液离心后的上清液中;当pH为7.0～8.5、CaC12投量为0.25～0.35 g/L、发酵液投加量的体积分数为1.5%～2.5%时,菌株PS1发酵液对4 g/L的高岭土悬浊液的絮凝效果最佳,絮凝率达到97%。菌株PS1所产絮凝剂对城市污水、啤酒废水、淀粉废水、医院废水的絮凝率可达90%以上。     

复合型絮凝剂处理景观水体

利用以生物絮凝剂(1 g/L MBF-28)与化学絮凝剂(5 g/L PAC)复配后的复合絮凝剂CBF28C处理景观水体,考虑了复配比、投加量、pH和投加顺序对处理景观水的影响。实验结果表明:对于反应体系为100 mL景观水体,当MBF-28与PAC溶液复配体积比为3∶1,反应体系pH为7.0,1 mL 1%CaCl2作助凝剂,1.5 mL CBF28C时,其絮凝效果最好,其COD,色度,TN,TP的去除率分别为90.7%,54.1%、46.6%和51.5%。最佳水力条件为:快速320 r/min,快搅时间45 s,慢速80 r/min,慢搅时间100 s。并且得出了前10 min内絮凝率的反应关系方程式。     

聚硅酸氯化铝处理皂素废水的研究

制备了聚硅酸氯化铝(PASC)絮凝剂，并用其进行了皂素废水处理实验。考察了絮凝剂投加量、pH值、搅拌速度对COD和浊度去除率的影响。结果表明，当絮凝剂投加量为9～13.5 mg/L、pH值5～7、搅拌速度150～250 r/min时，COD和浊度去除效果较好。最佳工艺条件为：絮凝剂投加量11.25 mg/L、pH值6、搅拌速度200 r/min。此时，COD去除率为93.7％，浊度去除率为97.5％。PASC的絮凝性能明显优于PAC。     

Development of a risk-based index for source water protection planning, which supports the reduction of pathogens from agricultural activity entering water resources

Source water protection planning (SWPP) is an approach to prevent contamination of ground and surface water in watersheds where these resources may be abstracted for drinking or used for recreation. For SWPP the hazards within a watershed that could contribute to water contamination are identified together with the pathways that link them to the water resource. In rural areas, farms are significant potential sources of pathogens. A risk-based index can be used to support the assessment of the potential for contamination following guidelines on safety and operational efficacy of processes and practices developed as beneficial approaches to agricultural land management. Evaluation of the health risk for a target population requires knowledge of the strength of the hazard with respect to the pathogen load (massxconcentration). Manure handling and on-site wastewater treatment systems form the most important hazards, and both can comprise confined and unconfined source elements. There is also a need to understand the modification of pathogen numbers (attenuation) together with characteristics of the established pathways (surface or subsurface), which allow the movement of the contaminant species from a source to a receptor (water source). Many practices for manure management have not been fully evaluated for their impact on pathogen survival and transport in the environment. A key component is the identification of potential pathways of contaminant transport. This requires the development of a suitable digital elevation model of the watershed for surface movement and information on local groundwater aquifer systems for subsurface flows. Both require detailed soils and geological information. The pathways to surface and groundwater resources can then be identified. Details of land management, farm management practices (including animal and manure management) and agronomic practices have to be obtained, possibly from questionnaires completed by each producer within the watershed. To confirm that potential pathways are active requires some microbial source tracking. One possibility is to identify the molecular types of Escherichia coli present in each hazard on a farm. An essential part of any such index is the identification of mitigation strategies and practices that can reduce the magnitude of the hazard or block open pathways.     

双氰胺-甲醛聚合物-聚合氯化铝复合絮凝剂的合成及应用

以双氰胺、甲醛、氯化铝为主要原料，加入添加剂合成了双氰胺-甲醛聚合物（DF）-聚合氯化铝（PAC）复合絮凝剂。采用模拟印染废水考察了各种因素对DF—PAC复合絮凝剂混凝脱色性能的影响。实验结果表明，在双氰胺、甲醛、氯化铝、添加剂加入量分别为29．1，57．8，4．8，12．5g，反应温度（70±1）℃、反应时间2．5h的条件下制得的DF—PAC复合絮凝剂的絮凝脱色性能良好，COD去除率不小于90％，色度去除率不小于99％。与PAC和DF絮凝剂相比，DF—PAC复合絮凝剂对实际印染废水的絮凝脱色效果更好。     

Determining Sources of Fecal Bacteria in Waterways

The microbiological contamination of waterways by pathogenic microbes has been, and is still, a persistent public safety concern in the United States and in most countries of the world. As most enteric pathogens are transmitted through the fecal–oral route, fecal pollution is generally regarded as the major contributor of pathogens to waterways. Fecal pollution of waterways can originate from wastewater treatment facilities, septic tanks, domestic- and wild-animal feces, and pets. Because enteric pathogens are derived from human or animal sources, techniques capable of identifying and apportioning fecal sources have been intensively investigated for use in remediation efforts and to satisfy regulatory concerns. Pollution of human origin is of the most concern, since human feces is more likely to contain human-specific enteric pathogens. Fecal indicator bacteria have been used successfully as the primary tool for microbiologically based risk assessment. However measurement of fecal indicator bacteria does not define what pathogens are present, or define the sources of these bacteria. Microbial source tracking (MST) methods that have the ability to differentiate among sources of fecal pollution are currently under development. These methods will ultimately be useful for risk assessment purposes and to aid regulatory agencies in developing strategies to remediate microbiologically impaired waterways.