能源微藻采收技术研究进展

能源微藻由于生长周期短、油脂含量高、可再生、低污染等优点,被认为是未来最有潜力替代化石能源的生物质能源。但是,目前能源微藻生产成本（尤其是在采收环节）过高,阻碍了其产业化进程。本文综述了国内、外能源微藻的采收方法,对絮凝、离心、过滤、气浮等传统方法的作用机理和采收效率进行了比较：絮凝法适用广,离心法效率高;过滤法处理个体大的藻类较为经济;气浮法工艺简单、能耗低。同时,阐述了能源微藻采收的新方法——磁选法、正向渗透技术、真空气举、微生物共生法等,其中,磁选法回收率高,正向渗透技术低污染,真空气举能耗低,微生物共生法可与传统方法相结合,减少化学絮凝药剂的使用。最后,指出了能源微藻采收过程中存在的问题以及今后的发展方向：可通过多种方法相结合来降低采收成本,以期为能源微藻早日实现产业化提供参考。     

助滤剂对絮凝物沉降和过滤性能的影响

<正> 一、前言 在液固分离过程中,对于一些直接通过沉降或一般的过滤方法(如真空过滤、加压过滤等)难以分离的悬浮液,化学预处理和物理预处理是改善悬浮液特性使其液固两相得以分离的两种行之有效的方法。目前,这两种预处理方法被广泛地应用于化工、冶金、矿山及环保水处理等行业。本文结合这两种方法的不同特点,将它综合应用于改善某厂粗制液净化过程中产生的悬浮液的沉降和过滤性能,以强化整个液固分离过程,达到液固两相有效分离的目的。     

五种絮凝剂采收小球藻的研究

针对微藻采收成本过高的问题,研究了硫酸铝、氯化铁、氢氧化钠、壳聚糖和聚丙烯酰胺5种絮凝剂对小球藻的采收效果,并对絮凝前后小球藻细胞内总碳水化合物、总蛋白质和总脂的含量进行了比较;观察了培养液的回收利用情况。结果表明,硫酸铝浓度为0.05 g/L,絮凝70 min,絮凝效率98.7%;氯化铁浓度为0.10 g/L,絮凝70 min,絮凝效率93.5%;氢氧化钠浓度为0.6 g/L,絮凝100 min,絮凝效率98.3%;壳聚糖浓度为0.010 g/L,絮凝12 min,絮凝效率98.1%;聚丙烯酰胺浓度为0.025 g/L,絮凝12 min,絮凝效率94.6%;絮凝前后小球藻细胞内总碳水化合物、总蛋白质和总脂含量没有明显的差别;回收的培养液可以重复利用。综合考虑,壳聚糖作为絮凝剂具有良好的应用前景。     

五种絮凝剂采收小球藻的研究

针对微藻采收成本过高的问题,研究了硫酸铝、氯化铁、氢氧化钠、壳聚糖和聚丙烯酰胺5种絮凝剂对小球藻的采收效果,并对絮凝前后小球藻细胞内总碳水化合物、总蛋白质和总脂的含量进行了比较;观察了培养液的回收利用情况。结果表明,硫酸铝浓度为0.05 g/L,絮凝70 min,絮凝效率98.7%;氯化铁浓度为0.10 g/L,絮凝70 min,絮凝效率93.5%;氢氧化钠浓度为0.6 g/L,絮凝100 min,絮凝效率98.3%;壳聚糖浓度为0.010 g/L,絮凝12 min,絮凝效率98.1%;聚丙烯酰胺浓度为0.025 g/L,絮凝12 min,絮凝效率94.6%;絮凝前后小球藻细胞内总碳水化合物、总蛋白质和总脂含量没有明显的差别;回收的培养液可以重复利用。综合考虑,壳聚糖作为絮凝剂具有良好的应用前景。     

发酵液絮凝过程絮凝体微尺度与分离性能

为探索发酵液絮凝分离过程规律以提高分离效率,本文在微观层面上研究发酵液絮凝过程中的剪切力、絮凝体尺度对絮凝体过滤分离效果的影响。以小诺霉素发酵液为研究对象,在絮凝过程中改变絮凝体所受的剪切力,使用激光粒度分析仪在0.02～2000 μm尺度内测定不同剪切力下絮凝体的粒度及粒度分布,并测定絮凝体的过滤速率及沉降速率。实验结果显示：絮凝体的粒度随剪切力的增大而减小,絮凝体的粒度分布宽度随剪切力的增大而增大;絮凝体的沉降分离速率随絮凝体粒度的增大而增大;在适度的剪切力下絮凝体有一适度的粒度及粒度分布宽度和较大的密实度,此时絮凝体的过滤分离速率有一最大值。实验结果表明：絮凝过程中的剪切力显著影响絮凝体的粒度、粒度分布和密实度,从而显著影响絮凝体的过滤速率及沉降速率。     

电渗析离子交换膜污染控制措施研究

为了解决电渗析技术处理垃圾渗滤液MBR产水过程中的膜污染问题，采用电絮凝和臭氧氧化2种预处理方式对MBR产水进行预处理，考察2种预处理方式对离子交换膜污染的控制效果。研究结果表明，经过电絮凝预处理后的废水COD和吸光度分别降低26.1%、 14.5%，经过臭氧氧化预处理后的废水COD和吸光度分别降低28.0%、 87.8%，电絮凝和臭氧氧化预处理使得膜电阻比没有经过预处理时分别下降了7.74%和52.87%，臭氧氧化预处理对电渗析过程中膜污染现象的预防效果优于电絮凝技术；采用pH值为11的NaOH溶液可以有效地恢复离子交换膜的性能，清洗后的膜电阻和脱盐效率均可以恢复到初始状态。     

不同前处理条件对水中氨氮监测的影响

纳氏试剂分光光度法是水中氨氮最常用的测定方法,除直接测定水样外,其前处理过程可分为絮凝沉淀取上清液、絮凝沉淀过滤、絮凝沉淀离心、蒸馏4种。通过比对不同前处理条件下的标准样品、实际水样的测定结果,得出絮凝沉淀离心作为前处理方法具备数据稳定、准确度高、实验效率高等优点。     

皂素废水化学预处理研究

分析了皂素生产废水中的主要污染物种类、含量。采用过滤中和、混凝沉降、吸附和氧化等化学方法预处理。处理后废水的pH值由2升高到6,酸性显著降低,COD去除率达80%,大部分有机物污染物已被除去,废水的色度也得到显著降低,有利于废水的后续处理。     

苯胺类废水处理技术研究进展

归纳了苯胺类废水产生的原因、危害及处理方法,重点介绍了目前常用的物理法、化学法和生物法。物理法主要包括吸附法、络合萃取法、膜分离法等,主要应用于苯胺类废水预处理阶段的分离、富集;化学法包括电催化氧化法、光催化氧化法、化学氧化法、超临界水氧化法、二氧化氯催化氧化法等,主要通过传质与化学反应的作用,将水中的有机污染物分离出来或分解为无害物质;生物法是利用微生物降解苯胺类污染物,适合处理低浓度苯胺废水,对废水的p H值、物质组成、温度等都有比较苛刻的要求。另外,还介绍了一些新型的处理技术和方法联用。     

高分子絮凝剂的开发和应用

一、前言对工业废水和各种生产过程中悬浮液的处理,如单独采用重力沉降、离心分离等物理方法,难于分离粒度接近于胶体的悬浮物,此时必须使用促进沉降分离的絮凝剂。通过絮凝来除去污染物质或使固液分离,在许多水处理技术的单元操作中是一种普遍应用的方法。由于絮凝沉降法较其它方法便宜,并且操作简便,因而在自来水和工业废水的处理中得到广泛应用。自古以来,人们就利用明矾等无机絮凝剂澄清水,近年来絮凝剂     

Development of an efficient electroflocculation technology integrated with dispersed‐air flotation for harvesting microalgae

BACKGROUND: Various methods, including centrifugation, filtration, electroflocculation, flocculation and flotation, have been developed for harvesting microalgae. However, some economic or technical problems still remain with current methods for algal recovery, such as high capital, energy and running costs, flocculant toxicity or low separation efficiency. Therefore, there is great interest in developing new efficient approaches for harvesting microalgae. RESULT: An efficient electroflocculation method integrated with dispersed‐air flotation has been developed for harvesting Botryococcus braunii. The recovery efficiency of B. braunii reached 93.6% after 30 min using an electroflocculation process. Microalgae recovery was improved significantly when the electroflocculation process was integrated with dispersed‐air flotation; the recovery efficiency of B. braunii reached 98.9% after 14 min. CONCLUSION: The present work demonstrated that electroflocculation integrated with dispersed‐air flotation is a promising method suitable for microalgae harvesting. The strategic air supply obviously shortened the algal recovery time in the process of electroflocculation due to facilitating algal aggregation and flotation to the solution surface. Copyright © 2010 Society of Chemical Industry     

Dewatering of microalgal culture for biodiesel production: exploring polymer flocculation and tangential flow filtration

BACKGROUND: Conventional biodiesel production relies on trans‐esterification of lipids extracted from vegetable crops. However, the use of valuable vegetable food stocks as raw material for biodiesel production makes it an unfeasibly expensive process. Used cooking oil is a finite resource and requires extra downstream processing, which affects the amount of biodiesel that can be produced and the economics of the process. Lipids extracted from microalgae are considered an alternative raw material for biodiesel production. This is primarily due to the fast growth rate of these species in a simple aquaculture environment. However, the dilute nature of microalgae culture puts a huge economic burden on the dewatering process especially on an industrial scale. This current study explores the performance and economic viability of chemical flocculation and tangential flow filtration (TFF) for the dewatering of Tetraselmis suecica microalgae culture. RESULT: Results show that TFF concentrates the microalgae feedstock up to 148 times by consuming 2.06 kWh m^?3 of energy while flocculation consumes 14.81 kWh m^?3 to concentrate the microalgae up to 357 times. Economic evaluation demonstrates that even though TFF has higher initial capital investment than polymer flocculation, the payback period for TFF at the upper extreme of microalgae revenue is ～1.5 years while that of flocculation is ～3 years. CONCLUSION: These results illustrate that improved dewatering levels can be achieved more economically by employing TFF. The performances of these two techniques are also compared with other dewatering techniques. Copyright © 2009 Society of Chemical Industry     

污泥深度脱水技术研究进展

随着经济的发展和国民生活水平的提高,污水污泥的排放量逐年增加,环境问题愈发严重,污泥的处理处置成为焦点问题,污泥脱水是制约污泥处置处理进一步发展的关键。本文针对目前污泥深度脱水技术开展,首先简述了不同来源污泥的分类及其基本特性,然后重点阐述了不同污泥预处理技术,分析了各污泥深度脱水技术作用机理,并对各自脱水效果及优缺点进行比较分析。结果表明,物理法中水热预处理对污泥的可脱水程度提升最大。较低声强、短时间的超声波处理对污泥脱水性能有着明显的改善。化学法在污泥过滤性能以及脱水速率方面有很大优势,酸碱处理后污泥zeta电位上升,污泥过滤性能及脱水速率得到改善。高级氧化法处理后污泥脱水效果高于酸碱处理,微生物细胞被溶解释放出有机物,可脱水程度改善。生物法处理污泥除改善污泥脱水性能外,还有对环境污染小等特点,但耗时较长。最后对污泥的后续脱水工艺进行综述,介绍了现存的主流脱水工艺,包括机械脱水、热干化技术、水热脱水工艺等;并针对不同的污泥后续利用方法,选取合适的预处理技术,提出相应优化的污泥处理工艺流程。     

Isolation and characterization of autoflocculating mutants of cyanobacterium Arthrospira platensis

Harvesting microalgae is a major concern for mass culture in industry. Flocculation is an easy and effective way to harvest microalgae. However, flocculation using chemical flocculants is not feasible for scaling-up due to their toxicity. As an alternative technique, mutation breeding of autoflocculating microalgae strain has been reported in this study. We characterized autoflocculating mutants of Arthrospira platensis (A. platensis) by ethyl methane sulfonate (EMS). The cells of mutants were aggregated during the culture and dry cell weight increased 1.2- to 1.8-fold compared to the wild type. Autoflocculation was induced highly at an optimal pH level of 9 and the flocculation efficiency reached almost 90%. Mutants showed higher flocculation efficiency irrespective of the addition of chemical flocculants. Thus, it is definitely useful to harvest microalgae using autoflocculating mutants in large-scale culture without any drawbacks of harvested algal biomass.     

能源微藻无泡采收新方法及其性能

采用低密度浮珠颗粒代替气泡的无泡采收方法,高效低成本采收能源微藻. 以常见能源微藻小球藻为例,以硅硼酸钠为浮珠,比较了浮珠浮选工艺与传统气浮法的区别,通过响应面法优化了浮珠浮选工艺. 结果表明,以硅硼酸钠为浮珠的无泡采收效果较理想,浮珠颗粒粒径、浓度和搅拌速率对采收率影响显著,颗粒直径56 ?m、浓度0.546 g/L、搅拌速率133 r/min的条件下采收率最好,达83.7%.     

Optimization of flocculation with tannin-based flocculant in the water reuse and lipidic production for the cultivation of Acutodesmus obliquus

This paper evaluated the optimization of natural flocculant in different conditions in a tubular photobioreactor using swine wastewater effluent as culture media in a pilot-scale microalgae production plant. This study aimed to assess the flocculation efficiency of Tanfloc SG via a central composite design (CCD), with varying Tanfloc SG concentration, biomass concentration and pH. Subsequently, the microalga Acutodesmus obliquus was cultivated in medium obtained from the recycled recovery of microalgae cells via flocculation with Tanfloc SG. Results showed that the recycled medium after flocculation with Tanfloc SG had a positive effect on the biomass and lipid production of A. obliquus.     

反渗透海水淡化预处理工艺

对不同海水预处理工艺进行了研究,对比分析了不同工艺产水浊度、化学需氧量（COD_Mn）、污染密度指数（SDI₁₅）等参数及不同预处理工艺对超滤膜膜比通量的影响。混凝-沉淀或气浮处理能够有效降低海水浊度,配合砂滤或纤维过滤,浊度可以降低到0.3NTU左右。当超滤处理海水时,无论采用何种预处理方法,其产水浊度和SDI₁₅都可以满足反渗透进水要求。直接超滤时,COD_Mn去除效果较差,超滤结合混凝-沉淀或气浮处理时,COD_Mn去除率有了较大的提高。预处理方法对超滤膜膜比通量影响较大,直接采用超滤进行处理时,超滤膜膜比通量衰减较快,经混凝-沉淀或气浮处理后,膜比通量衰减有所减缓,进一步经砂滤或纤维过滤后,膜比通量的衰减得到了较好的控制。采用混凝-沉淀/纤维过滤预处理工艺时超滤膜膜比通量衰减最低。     

不同预处理方法对无机陶瓷膜精制甘草水提液膜过程的影响研究

探讨不同预处理方法对无机陶瓷膜精制甘草水提液膜分离过程的影响。以甘草水提液为实验体系,采取调节pH值、絮凝、离心和粗滤作为预处理方法,考察0.2μm Al2O3无机陶瓷膜微滤经预处理后的甘草水提液时的膜通量、膜污染度、膜阻力分布、指标性成分甘草酸的保留率。表明pH7时膜稳定通量较大;粗滤、离心和调节pH7时甘草酸的保留率较高,壳聚糖絮凝时甘草酸的保留率最低。不同的预处理方法对甘草的膜精制过程具有不同的影响,高速离心和调节pH值是甘草水提液膜分离工艺中较好的两种预处理方法。     

Separation of nitrocellulose fine particles from industrial effluent with organic polymers

Polymers were used in the experiments to determine optimum type and dosage requited for effective treatment of an industrial effluent containing nitrocellulose fine particles. It was found that (a) contact flocculation filtration was not effective for treating the nitrocellulose-manufacturing wastewater due to the high initial turbidity; (b) mixing, flocculation, and settling of the wastewater with cationic polyelectrolyte and bentonite clay gave greater than 95% turbidity removal; (c) with the same optimum chemical dosages, mixing, flocculation and centrifugation also gave about 97% turbidity removal; and (d) with the same optimum chemical dosages, mixing, flocculation, sedimentation and filtration removed 99.9% of the wastewater turbidity.