Treatment of phosphate-containing oily wastewater by coagulation and microfiltration

The oily wastewater generated from pretreatment unit of electrocoating industry contains oils, phosphate, organic solvents, and surfactants. In order to improve the removal efficiencies of phosphate and oils, to mitigate the membrane fouling, coagulation for ceramic membrane microfiltration of oily wastewater was performed. The results of filtration tests show that the membrane fouling decreased and the permeate flux and quality increased with coagulation as pretreatment. At the coagulant Ca （OH）2 dosage of 900 mg/L, the removal efficiency of phosphate was increased from 46.4% without coagulation to 99.6%; the removal of COD and oils were 97.0% and 99.8%, respectively. And the permeate flux was about 70% greater than that when Ca（OH）2 was not used. The permeate obtained from coagulation and microfiltration can be reused as make-up water, and the recommended operation conditions for pilot and industrial application are transmembrane pressure of 0.10 MPa and cross-flow velocity of 5 m/s. The comparison results show that 0.2 μm ZrO2 microfilter with coagulation could be used to perform the filtration rather than conventional ultrafilter, with very substantial gain in flux and removal efficiency of phosphate.

Treatment of pharmaceutical wastewater containing recalcitrant compounds in a Fenton-coagulation process

The advanced treatment using integrated Fenton＇s reaction and coagulation process was investigated in this study. Before the advancement, the pharmaceutical wastewater containing lincomycin hydrochloride was pretreated by UASB （upflow anaerobic sludge bed） and a SBR （sequencing batch reactor） process. The residual recalcitrant compounds, measured by gas chromatographymass spectrometry （GC-MS）, mainly consisted of alcohols, phenols, and nitrogenous and sulfur compounds. The experimental results indicated that when the Fenton＇s reaction was conducted at pH=3.0, H2O2CODOcr=0.27, H2O2/Fe^2＋=3：1 and 30 min of reaction time, and the coagulation process operated at a sulfate aluminum concentration of 800 mg/L and pH value of 5.0, the color and COD in the wastewater decreased by 94% and 73%, respectively; with a finale COD concentration of 267 mg/L and color level of 40 units, meeting the secondary standard of GB8978-1996 for industrial wastewater.

Pilot study on treatment of low turbidity and low temperature water by coagulation-immersed membrane process

The objective of this paper was to investigate the practicability of coagulation-immersed membrane process during low-temperature period through the study of steady operation,chemical cleaning methods,water quality and agent consumption.Experimental results showed that:membrane performance decreases with the reduction of temperature,but low temperature has little effect on stable operation of immersed membrane when coagulation as pretreatment.EFM with 1200 mg/L sodium hypochlorite after every 48 filtration cycles was made for reducing membrane fouling efficiently,and the method,with 1.5% sodium hydroxide and 3500 mg/L sodium hypochlorite for 10 h and then 2% hydrochloric acid for 4 h,is an appropriate cleaning method under low temperature.Compared with convention treatment process,immersed membrane process not only has same agent consumption,but also permeated water quality is more superior such as fine removal effect on turbidity with average 0.10 NTU.Therefore,coagulation-immersed membrane process is more appropriate for increasing water quality demand and the treatment of low turbidity and low temperature water.

DYNAMIC MODEL AND SIMULATION OF THE PLATELETS'ROLE IN BLOOD COAGULATION

In order to confirm which process is the most important in the blood coagulation cascade,a dynamic model on the function of platelets in blood coagulation is presented based on biochemical experiments.Based on qualitative analysis and mathematical simulation,a series of conclusions about the influence of the activation rate of factor VIII and factor IX on the generation of thrombin(IIa)are drawn.It is evident that the pro-coagulation stimulus must exceed a threshold value to initiate the coagulation cascade.The value is related to the binding constant d_2 of the platelet. The stability of the equilibrium value is also related to the pro-coagulation stimulus. This article also evaluates the influence of the stimulus strength and the activated rate parameter of platelets on thrombin.The proportion of platelets activated at any given time is designated c.To each c,we obtain a maximum concentration of thrombin.It is evident that when the level of factor IX is below 1% of the normal level,the rate of thrombin generation reduces dramatically,resulting in severe bleeding tendency.

Purification and characterization of Al_(13) species in coagulant polyaluminum chloride

Nano-Al13 was separated and purified by four methods to investigate its characteristic, and was analyzed by Al-Ferron timed complexation spectrophotometer, ^27Al-NMR （nuclear magnetic resonance）, and transmission electron microscopy （TEM）. Coagulation efficiency of nano-Al13, polyaluminum chloride （PAC）, and AlCl3 in synthetic water were also investigated by jar test. The dynamic process and aggregation state of kaolin suspensions coagulating with nano-Al13, PAC, and AlCl3 were also investigated. The experimental results indicated that the efficiency of gel column chromatography method was the highest for separating PAC solution with low Al concentration. Ethanol and acetone method was simple and could separated PAC solution with different Al concentrations, while silicon alkylation white block column chromatography method could separate PAC solution only with low Al concentration. The SO4^2-/Ba^2＋ displacement method could separate PAC solution with high Al concentration, but extra inorganic cation and anion could be introduced into the solution during the separation. The coagulation efficiency and dynamic experimental results showed that nano- Al13 with a high positive-charged species was the main species of electric neutralization in coagulation process, and it could reduce the turbidity and increase the effective particles collision rate efficiently in coagulation process. Its coagulation speed and the particle size of coagulant formed were of greatest value in this study.

The Use of Fermented Whey as a Coagulant in Tofu Industries

Fermented whey （a by-product from tofu industry） has been used as a coagulant in tofu manufactures in Indonesia. This research aimed to study effects of fermented whey on coagulation efficiency and physicochemical characteristics of tofu, compared to other acid coagulants （acetic acid and glucono-delta-lactone （GDL）） and salt coagulants （calcium sulfate and natural gypsum）. A randomized block design with a single factor was used in this research. Fermented whey could be used as coagulant in tofu manufacturing. Physicochemical characteristics of tofu from fermented whey were not significantly difference compared to tofu from calcium salt and acid coagulants. Coagulation efficiencies （CF, TSIL TPR and TB~） of fermented whey are lower than that from calcium salt coagulants （calcium sulphate and natural gypsum）. Fermented whey showed no significant differences in tofu properties and parameters of coagulation process, compared to GDL and acetic acid.

Characterization of cake layer structure on the microfiltration membrane permeability by iron pre-coagulation

A cake layer is formed by coagulation aggregates under certain transmembrane pressure in the coagulation-microfiltration （MF） process. The characteristics of humic acid aggregates coagulated by different iron-based coagulants, such as charge, size, fractal dimension and compressibility, have an effect on the cake layer structure. At the optimum iron dose of 0.6 to 0.8 mmol/L for ferric chloride （FC） and polymer ferric sulfate （PFS） pre-coagulation, at the point of charge neutralization for near zero zeta potential, the aggregate particles produced possess the greatest size and highest fractal dimension, which contributes to the cake layer being most loose with high porosity and low compressibility. Thus the membrane filterability is better. At a low or high iron dose of FC and PFS, a high negative or positive zeta potential with high charge repulsion results in so many small aggregate particles and low fractal dimension that the cake layer is compact with low porosity and high compressibility. Therefore the membrane fouling is accelerated and MF permeability becomes worse. The variation of cake layer structure as measured by scanning electric microscopy corresponds with the fact that the smaller the coagulation flocs size and fractal dimension are, the lower the porosity and the tighter the cake layer conformation. This also explains the MF membrane flux variation visually and accurately.

Review on Optimization of Drinking Water Treatment Process

In the drinking water treatment processes, the optimization of the treatment is an issue of particular concern. In general, the process consists of many units as settling, coagulation, flocculation, sedimentation, filtration and disinfection. The optimization of the process consists of some measures to decrease the managing and monitoring expenses and improve the quality of the produced water. The objective of this study is to provide water treatment operators with methods and practices that enable to attain the most effective use of the facility and in consequence optimize the cubic meter price of the treated water. This paper proposes a review on optimization of drinking water treatment process by analyzing all of the water treatment units and gives some solutions in order to maximize the water treatment performances without compromising the water quality standards. Some practical solutions and methods are performed in the water treatment plant located in the middle of Morocco (Meknes).

Chemical oxygen demand reduction in coffee wastewater through chemical flocculation and advanced oxidation processes

The removal of the natural organic matter present in coffee processing wastewater through chemical coagulation-flocculation and advanced oxidation processes （AOP） had been studied. The effectiveness of the removal of natural organic matter using commercial flocculants and UV/H202, UV/O3 and UV/H2O2/O3 processes was determined under acidic conditions. For each of these processes, different operational conditions were explored to optimize the treatment efficiency of the coffee wastewater. Coffee wastewater is characterized by a high chemical oxygen demand （COD） and low total suspended solids. The outcomes of coffee wastewater treatment using coagulation-flocculation and photodegradation processes were assessed in terms of reduction of COD, color, and turbidity. It was found that a reduction in COD of 67% could be realized when the coffee wastewater was treated by chemical coagulation-flocculation with lime and coagulant T-1. When coffee wastewater was treated by coagulation-flocculation in combination with UV/H2O2, a COD reduction of 86% was achieved, although only after prolonged UV irradiation. Of the three advanced oxidation processes considered, UV/H2O2, UV/O3 and UV/H2O2/O3, we found that the treatment with UV/H2O2/O3 was the most effective, with an efficiency of color, turbidity and further COD removal of 87%, when applied to the flocculated coffee wastewater.

凝固剂及加工条件对豆腐凝胶形成及品质影响研究进展

豆腐的本质是一种蛋白质凝胶体,是大豆蛋白(主要是7S和11S球蛋白)在热处理下发生变性使蛋白质分子结构展开,再通过盐离子、氢离子或酶等凝固剂作用下发生聚集,形成致密均匀且具有网状结构蛋白凝胶。豆腐凝胶的形成及豆腐品质受多种因素的影响。本文从凝固剂种类(盐类、酸类和酶类凝固剂)以及加工条件(加工原料、制浆方法、豆浆体系pH、热处理条件)角度出发,阐明凝固剂及加工条件对豆腐凝胶形成以及品质的影响研究进展。以期为豆腐制品的工业化生产提供理论指导,为豆腐食品的研究开发与品质调控提供科学依据。

基于混凝预处理的超滤净水工艺研究进展

膜污染是超滤工艺大规模运用的主要限制性因素,介绍超滤膜净水工艺膜污染的原理及其污染物。详述基于混凝预处理的三种超滤膜工艺:传统超滤工艺、短流程超滤工艺、一体式絮体-超滤工艺。以短流程超滤工艺为重点,阐述近年来以混凝预处理工艺来缓解超滤净水工艺膜污染的研究成果。总结了滤饼层结构对膜污染的影响,以及混凝预处理缓解超滤膜污染的作用原理,为膜法水处理工艺技术工程应用提供参考。

基于图像处理和模糊控制的絮凝剂智能投加系统设计

净水处理工艺中,混凝过程是一个大滞后、非线性的复杂系统。针对其特点并结合目前国内外加药控制研究现状,开发了一种基于絮凝体图像处理、模糊逻辑控制的前馈-串级智能加药系统。通过水样图像采集与处理提取絮凝体特征关键参数,计算絮凝体等效直径,建立投加模型确定絮凝剂投加量,再通过模糊PID控制及前馈补偿实现絮凝剂的全自动调节和精准投加。系统监控及性能分析显示,与传统手工投加对比,智能投加系统沉淀后出水浊度标准偏差降低27%,与设定值的相对误差控制在10%以内,絮凝剂的投加量节省11.04%,在絮凝剂投加量和处理效果上具有显著优势,表现出良好的可行性和推广潜力。

陶瓷膜在饮用水处理中的应用现状

水是人类生存所必需的资源。近年来,我国的饮用水水质标准不断提高。为了满足更高的标准,自来水厂开始使用膜过滤技术取代传统过滤技术。作为一种先进的水处理技术,膜过滤技术已经在各个领域得到广泛应用。与有机膜相比,陶瓷膜具有化学性能稳定、耐酸碱、热稳定性好、机械强度高、回收率高、使用寿命长等优点,在饮用水领域有更广阔的应用前景。本文旨在阐述陶瓷膜的结构特点和过滤机理,并探讨陶瓷膜在饮用水处理中的研究进展。通过对陶瓷膜饮用水处理工艺进行分析,发现原水经过混凝、吸附、臭氧氧化预处理后,陶瓷膜的过滤性能有明显的提升。文章还分析了陶瓷膜的抗污染性能,并强调了其在维护成本方面的优势。最后,对优化陶瓷膜成本、多元陶瓷膜集成工艺和陶瓷膜大规模运行成本估算等未来研究方向进行了展望。

不同絮凝剂对钻井泥浆的处理效果及絮凝机理

为研究不同絮凝剂对钻井泥浆的絮凝效果,采用破胶絮凝的方法对含水率高、成分复杂的山西某煤层气废弃钻井泥浆进行处理,研究不同破胶絮凝剂和助凝剂种类及投加量等因素对废弃钻井泥浆处理效果的影响,并利用扫描电子显微镜(SEM)探究了破胶助凝的机理。结果表明:2000 mg/L的硫酸铝破胶絮凝效果最优,10 mg/L的非离子聚丙烯酰胺(NPAM)与其协同处理效果最佳,处理后的液相色度、COD_(Cr)、悬浮物含量和泥饼含水率分别为20倍、61.98、32.50 mg/L、78.64%;硫酸铝的电中和作用可以和NPAM桥联网捕作用产生良好的协同效果,能够显著加快泥浆中颗粒物的絮凝沉降,增大絮体体积和疏松程度,从而降低液相污染物含量和泥饼含水率。研究结果可为废钻井泥浆的絮凝处理提供一定的参考和理论依据。

基于图像处理判断水混凝中矾花性能的研究及应用进展

原水预处理主要分为混凝、沉淀和过滤3个阶段,混凝中的絮凝过程直接影响矾花结构与出水浊度;目前多采用检测出水浊度方法来控制混凝剂加药量,但因时间滞后无法快速反映混凝效果与反馈调节加药量。随着计算机技术的快速发展,利用矾花图像处理技术能够实现快速、准确、实时检测絮凝状态,从而更准确控制加药量,提高混凝效果。从计算机视觉技术角度,概述了絮凝中矾花图像采集与处理的技术特点,介绍了实时跟踪和计算矾花结构特征参数如等效粒径、分形维数等方法,并给出了部分试验结果,通过这些参数可以判断最佳混凝效果,为混凝控制与加药提供依据。

点浆条件对酸浆豆腐品质的影响

为探究点浆时豆乳温度、点浆后蹲脑温度和蹲脑时间对酸浆豆腐品质的影响,提高酸浆豆腐品质,本研究利用质构分析、SDS-PAGE和低场核磁等技术分析了豆腐品质、豆乳中蛋白凝固过程、大豆蛋白各亚基含量和水分分布的变化规律。结果表明,点浆时豆乳温度对豆乳沉淀中蛋白和大豆蛋白各亚基含量无显著影响,但对豆腐品质和水分分布有较大影响。当点浆时豆乳温度为75℃时,豆腐的硬度最小,而其弹性、得率、含水量、保水性、感官得分和T 21弛豫时间最大。蹲脑温度和蹲脑时间对豆腐品质、豆乳沉淀中蛋白含量和大豆蛋白各亚基含量影响显著,当蹲脑温度75℃和蹲脑时间20 min时,豆腐硬度最小为15.80 N,而弹性、得率、含水量、保水性和T 21弛豫时间最佳,分别为5.15 mm、241.3%、76.36%、65.68%、43.29 ms,且豆腐品质豆乳沉淀中蛋白含量最佳。当点浆时豆乳温度为75℃、蹲脑温度为75℃和蹲脑时间20 min时,豆腐品质和感官得分最优。

基于HIS数据的凝血功能障碍伴出血事件自动监测模块的构建与优化——以替加环素为研究案例

目的:依托临床药品不良事件主动监测与智能评估警示系统(ADE-ASAS-Ⅱ)构建凝血功能障碍伴出血事件监测模块,探索复杂诊断条件下药品不良反应(ADR)自动监测方法。方法:以替加环素为研究案例,基于决策树算法将触发器技术与自然语言处理技术相结合,构建量化-文本复合监测模块,并基于某大型三级甲等医院的医院信息系统(HIS)数据挖掘凝血功能障碍相关出血事件。反复优化模块设置,以人工评价结果为“金标准”,比较不同优化方案下模块监测效能以确定最佳设置。统计阳性事件的发生率、基本特征。结果:共监测2019—2022年2345例使用替加环素的患者,人工评价后确定阳性病例83例。模块初始设置下,报警985例,精确率为7.72%,召回率为91.57%,F1值为14.23%。反复优化后,报警475例,召回率不变,精确率提升至16.00%,F1值提升至27.24%;1870例被ADE-ASAS-Ⅱ系统标记为阴性病例,可减少约80%的人工评价工作量。1359例符合纳入与排除标准的患者中(阴性1276例,阳性83例),凝血功能障碍伴出血事件的发生率为6.11%。结论:凝血功能障碍伴出血事件模块的开发提升了ADE-ASAS-Ⅱ系统对复杂诊断条件下ADR的检出效率,拓展了联合结构化与非结构化HIS系统数据识别ADR的监测方法。后续需扩大样本以验证模块稳定性,并持续改进系统算法,以进一步提高监测效率。

物化预处理-生化组合工艺处理草甘膦生产废水工程实例

对不同工艺废水采用物化方法分质预处理后,利用厌氧-缺氧-CAST组合工艺处理综合废水,设计处理量为470 m^(3)/d。运行实践表明:中和反应-混凝沉淀对总磷的去除率可以达到46%,整个工艺处理出水COD稳定低于500 mg/L,总磷稳定低于8 mg/L,出水水质达到接管要求。

植物叶蛋白提取工艺及蛋白肽制备技术研究进展

随着社会发展水平的提升,食物来源日益多元化,人们对优质蛋白质食物消费量不断增加,促使植物蛋白资源的开发和提取技术兴起。植物蛋白有动物蛋白无可比拟的优势,通过对叶蛋白深加工制备的蛋白肽,可以进一步提升植物蛋白的营养价值。因此,植物叶蛋白的提取及精深加工备受人们关注,植物叶蛋白的提取方法更是多种多样,最佳提取工艺参数也有深究。本文在前人研究的基础上对不同的叶蛋白经典提取方法及精深加工生产蛋白肽的方法进行整理综述,从主要的叶蛋白提取环节着手,回顾了各提取方法的原理知识、操作注意事项并进行优缺点评价,以期为后续植物叶蛋白提取研究及蛋白肽的制备提供理论依据及指导意见。