Cross-Flow Microfiltration of Industrial Oily Wastewater: Experimental and Theoretical Consideration

Microfiltration of industrial oily wastewater was performed using polyamide membrane. A rectangular cross flow membrane cell was used for the experiments. Effects of different operating parameters such as transmembrane pressure drop and Reynolds numbers on the steady state permeate flux and oil rejection was investigated in detail. Initial oil concentration in the industrial oil-water emulsion was found to be 192 mg/L with average oil droplet range size 0.01 to 47 µm. The treated industrial oily water was characterized in terms of electrical conductivity, total dissolved solids (TDS), and chemical oxygen demand (COD). It was observed that the steady state permeate flux increased with transmembrane pressure drop and Reynolds numbers. The oil concentration in permeate was found to be around 4.5 mg/L, after treatment, which was lower than the permissible discharge limit. The results showed that microfiltration was an efficient and ecologically suited technology for the treatment of industrial oily wastewater. The cross flow velocity was considered in both laminar and turbulent regimes. A model was proposed by combining of Brownian diffusion and shear-induced diffusion to predict the steady state permeate flux data at different Reynolds numbers and different transmembrane pressure drops.     

Polyethersulfone composite hollow-fiber membrane prepared by in-situ growth of silica with highly improved oily wastewater separation performance

In order to reduce surface aggregation and enhance the performance of PES membranes, a hydrophilic PES/TEOS HF membrane was developed for the treatment of wastewater containing oil. PES/TEOS was prepared via a sol-gel self assembly and dry–wet spinning method. Silicon dioxide sol was prepared from a mixture of tetraethoxysilane, ethanol, water, and acetic acid (acting as the catalyst). HF hybrid membranes were produced from dope solutions containing polyethersulfone, polyethylene glycol, silicon sol, and NMP. The membranes were characterized by field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), energy-dispersive X-ray spectroscopy (EDX), porosity, fourier transform infrared spectroscopy (FTIR), and contact angle measurements. The composite membranes were successfully used to treat wastewater containing oil and their separation performance were evaluated. The PES/TEOS-2 membrane displayed the best performance, with a permeate flux of 90.937 L/m² h and an oil retention of 99.98%. In addition, this membrane showed a higher pure water flux of 102.43 L/m² h as compared to PES-0 and PES/SiO₂–1 membranes (87.347 L/m² h and 91.949 L/m² h, respectively). The PES/TEOS-2 membrane also presented enhanced antifouling behavior with a FRR and a RFR of 93.33% and 11.22%, respectively. In addition, this membrane displayed excellent long-term recycling properties, making it a desirable candidate for oily wastewater separation applications.     

煤化工废水中油泥的聚结分离与水中有机物的去除效果

针对煤化工废水中存在的高浓度油及油泥的问题,本研究制备了高电荷、低聚合度的无机复合材料和低电荷、高聚合度的有机复合材料,探究无机、有机复合材料协同作用下对煤化工废水中油及油泥的聚结分离效果以及对废水中有机物的去除特性。结果表明,无机、有机复合材料在复合比例为500∶1的条件下,废水中油和固体悬浮物（SS）去除率分别达到55%和98%;现场试验发现,无机、有机复合材料对油含量1700～2000mg/L,SS含量为1500～2000mg/L的废水,油和SS的去除率一直稳定于50%和95%左右,表现出较好的稳定性;进一步对废水中典型有机物的去除效果研究可知,该复合材料同时也对废水中各类有机物有较好的去除效果,多环芳烃（PAHs）、苯系物和酚类物质的去除率可达到82.85%、41.9%和37.56%。可以发现,无机、有机复合材料可有效解决煤化工废水中油及油泥的去除问题,具有广阔的产业化应用前景。     

多核无机高分子絮凝剂PMC红外结构及其性能

分别用含Fe、Mg、Al和Zn金属核的络合剂(FMA)及含活性SiO2的交联剂(PSi)改性增效聚合氯化铝(PAC),合成了一种硅稳定型多核无机高分子絮凝剂(PMC)。通过分析PMC絮凝剂的红外光谱(FT-IR)发现,在波长为900～1100cm-1、1500～1700cm-1和3000～3600cm-1波段,PAC的特征吸收峰消失,原有基团也发生了一定程度的畸变,多金属核间的羟基化作用使得PMC中产生了有别于PAC的新化学键,表明PMC分子结构中可能不再有单核无机高分子聚合物。这种增效反应导致PMC的相对分子质量比PAC增大,选择性荷电吸附能力增强,因而特别适合处理油田含油污水和印染污水等变组分污水。对天然水体和印染污水的对比絮凝实验表明,PMC絮凝剂的絮凝速度、脱色率和悬浮物去除率均高于传统絮凝剂PAC和PFS(聚合硫酸铁)。对油田采油污水和炼油厂含油污水,经质量浓度为150～250mg·L-1的PMC强化絮凝处理后,污水的化学耗氧量(COD)和含油率均可达到国家规定的污水回注标准或排放标准。     

Study on Riboflavin Recovery from Wastewater by a Batch Foam Separation Process

Abstract

A batch recovery of riboflavin via foam separation from industrial simulative wastewater was studied using a cationic surfactant, cetyltrimethyl ammonium bromide (CTAB). The experimental parameters examined were the surfactant concentration, air flow rate, pH, and foam height. Under optimal operating conditions obtained through an orthogonal experiment, the maximum enrichment ratio of 48.7 was achieved for riboflavin along with 99.3% removal efficiency. The optimal operating conditions had the concentration of CTAB at 0.3 g/L, air flow rate at 400 ml/min, foam height at 90 cm, and pH at 12. Therefore foam separation proved to be an effective method to recover the riboflavin in terms of the good enrichment and removal efficiency.     

Preparation and Performance Evaluation of Polyethersulfone Hollow Fiber Membranes for Ultrafiltration Processes

In this article, polyethersulfone hollow fiber membranes were prepared using dry–jet–wet spinning process via phase inversion method. Effects of polyethersulfone and polyethylene glycol concentrations and coagulation bath temperature, air–gap distance, and take-up speed on morphology of the prepared membranes were investigated. Based on L₁₆ orthogonal array of Taguchi experimental design, 32 membranes were prepared. An experimental investigation on separation of the industrial oil from oily wastewater has been done. The results showed that synthesized polyethersulfone membranes was effective and suitable for the treatment of oily wastewater to achieve up to 66.6 and 95.0% removal of total organic carbon and oil–grease content, respectively, with a flux of 72.3 L/(m²h).     

Synthesis and study of new nonionic polyether water clarifier for oily wastewater

In order to solve the problem of oily wastewater treatment in Shengli Oilfield, tert-butyl phenol (TP) series nonionic polyether water clarifiers were synthesized by polymerization with p-tert-butyl phenol (PTBP) as the initiator. The water clarifiers were characterized by Fourier-transform infrared spectroscopy (FT-IR) and the interfacial tension test was carried out. The TP series of water clarifiers effect were evaluated by the oil content and suspension content in the clean water experiments. In addition, the effects of dosage and temperature on the water effect were discussed through the control variable method. The experimental results showed that the oil removal rate of TP6 can reach 95% and the suspension removal rate can reach 92% when the dosage of water clarifier was 40 mg/L, the cleaning water temperature was 55°C, and the cleaning water time was 30 min. The oily wastewater colour after cleaning was clear and transparent with the TP series of water clarifiers, and the effect was better than with commercial water clarifiers.     

纳米颗粒作为稳泡剂泡沫分离酪蛋白的工艺

为了增强乳制品废水中低浓度酪蛋白（casein，CS）的泡沫性能进而提高其泡沫分离效果，首先采用十二烷基二甲基甜菜碱（dodecyl dimethyl betaine，BS12）改性疏水二氧化硅纳米颗粒（silica nanoparticle，SNP），以制备接触角为61.6°±3.1°的部分疏水二氧化硅纳米颗粒（BS12-SNP），分别从静态和动态泡沫性能两个角度来研究BS12-SNP作为稳泡剂的功效。实验结果表明，BS12-SNP作为稳泡剂可以抑制泡沫排液和泡沫聚并，进而增强20.0～60.0mg/L酪蛋白的泡沫稳定性。与不添加BS12-SNP相比，添加BS12-SNP后的酪蛋白废水泡沫半衰期最大可提高6.5倍。泡沫分离实验表明，在BS12-SNP浓度50mg/L、气速250mL/min、装液量500mL的条件下，上述浓度范围内的酪蛋白回收率最高可达94.2%，此时富集比为12.3。本文开发了一种表面功能化纳米颗粒代替表面活性剂的泡沫分离工艺，实现了废水中酪蛋白的有效回收。     

双项预处理+CASS工艺处理船舶废水研究

以船舶废水为研究对象,采用双项预处理和CASS池处理组合工艺对其进行处理,重点考察了聚合氯化铝和聚合氯化铁用量对废水中的油相去除效果的影响,以及由高浓度COD和高盐度引起的活性污泥生物相演替规律。结果表明,当聚合氯化铝为0.25mg.L-1,聚合氯化铁的投量为2mg.L-1时对石油类的去除效果最好,此时石油类的浓度可降至22.71mg.L-1。CASS池能够在满负荷工况下实现稳定运行,出水COD、BOD和石油类分别为40~85mg.L-1,14~20 mg.L-1和4~6 mg.L-1时,对COD和石油类的去除率分别高达87%和98%以上。     

铁盐共沉淀泡沫浮选法去除废水中Cr(VI)的应用研究

采用铁盐共沉淀泡沫浮选法去除废水中Cr(VI),用FeSO4将六价铬还原成三价状态,考察了还原剂用量、捕捉剂品种及pH对总铬去除率的影响。结果表明,对浓度为10 mg/L的含Cr(VI)模拟废水,使用FeSO4作还原剂,LAS作捕捉剂,铁铬摩尔比为7∶1,pH=10,鼓泡10 min的条件下,Cr(VI)去除率可达99.1%。     

油水分离剂在化学驱采出液和含油污水处理中的应用

针对大庆油田聚北-1联合站处理的化学驱采出液和含油污水因含有表面活性剂(52 8mg/L)、碱(294 5mg/L)和聚合物(347 5mg/L)而油水分离困难,造成该站处理后污水含油量严重超标的问题。从非离子型药剂的思路出发研制了适用于含表面活性剂、碱和聚合物的反相原油乳状液的油水分离剂。在聚北-1联合站原有的两级沉降和一级石英砂过滤含油污水处理工艺不变的条件下,在采出液中投加60mg/L本文研制的油水分离剂(药剂费用为0 51元/m3)后,该站处理后污水的平均含油量由投加油水分离剂前的99 0mg/L降低到9 9mg/L。     

聚结式过滤器处理含油污水实验研究

研究采用聚结式过滤器处理含油污水,选取润滑油配制含油污水,研究了初始含油量、流量、静置时间以及乳化程度等参数对分离效果的影响.实验结果表明,初始含油量越高、乳化程度越小、除油效果越好.针对开发的聚结式含油污水过滤器,对其操作工艺参数进行了优化,流量应控制在600L/h左右,静置时间以30min为宜.     

pH敏感型纳米粒子的制备及其对含油污水的净化

首先采用共同沉淀法制备了Fe_3O_4磁性纳米粒子,再通过正硅酸四乙酯水解包覆在其表面形成SiO_2壳层,最后将硅烷偶联剂KH-550在Fe_3O_4@SiO_2上进行接枝改性,得到了表面氨基功能化的磁性纳米粒子(A-MNPs)。通过TEM、FTIR、VSM对纳米粒子的微观形貌、化学组成、磁学性能进行了测试,并将其应用于油田含油污水的净化处理。结果显示:表面氨基化的结构使A-MNPs具有pH敏感性,因此可通过改变pH实现A-MNPs的重复使用,当pH=4时A-MNPs达到最佳除油效果。当A-MNPs浓度为200 mg/L时便可将模拟含油污水透光度提高到99.4%;500mg/L的A-MNPs重复使用10次后仍可使净化后含油污水的透光度保持在80%以上;A-MNPs对由不同浓度的氯化钠、高岭土、乳化油、部分水解聚丙烯酰胺(HPAM)组成的多种模拟污水也有较好的净化效果,375 mg/L的A-MNPs可使含油质量浓度10 g/L复杂模拟污水透光度达到86.5%以上。     

不溶性阳极电解气浮法处理含油废水的试验研究

采用石墨作阳极对含油废水进行电解气浮处理研究,对电解法处理乳化含油废水的作用机理进行了初步探索,考察了电流强度,电解时间,极间距和pH值对废水中油去除率的影响。正交实验表明,电解时间是影响废水除油率的最显著因素。在电流强度为0.38A,电解时间为28min,极间距为1.5cm,原水pH值为7.1的条件下进行电解气浮实验,废水除油率达到93.59%。     

某铁路车辆厂含油废水混凝预处理试验研究

西北某车辆厂含油废水为达到回用水要求,需对其进行深度处理。混凝作为预处理,其效果好坏直接影响气浮及精细过滤,为此进行了影响混凝效果因素的正交试验。通过研究确定出适合该厂水质的混凝预处理控制条件为：混凝剂种类为PAC（I）,投加量为30 mg/L,搅拌速度250 r/min,搅拌时间90 s,助凝剂用量为0.4 mg/L。使混凝后出水浊度、COD、油分别在4.5 NTU、55 mg/L、6.0 mg/L左右,与原来混凝后出水浊度10~26 NTU、COD60~92 mg/L、油7.4~10.6 mg/L相比有较大提高,为后续处理作了稳定可靠地保。     

电-Fenton法处理模拟含油废水影响因素的研究

采用电-Fenton法对模拟含油废水进行处理。实验结果表明：影响除油率的因素主次顺序为：pH值、电解电压、反应时间、初始含油浓度、电解质浓度。单因素分析得出电-Fenton法处理模拟含油废水的最优反应条件：pH值为2.5,电解电压为10V,反应时间为60min,初始含油浓度为100mg/L,电解质浓度为30g/L。在最优条件下除油率达到50.5%。     

浅谈油库污水处理工艺

我国沿海港口众多,很多油库每天需要清洗油罐并且定期排放罐内分离出来的含油污水,而油轮需要清理压舱水,其压舱水的含油量最大可达20％,而且油质复杂。含油废水中的含油量,一般为几十至几千mg／L,最高可达数万mg／L。而国家规定的允许排放标准仅为10mg／L。根据含油废水中油类存在形式的不同,通常分为浮油、分散油、乳化油和溶解油四种。含油废水的治理原则：首先应该考虑尽可能多的回收含油废水中的油,对治理过的水,应达到国家《城市污水再生利用城市杂用水水质》GB／T18920—2002标准的要求。     

含十二烷基苯磺酸钠废水的多级泡沫分离研究

采用多级泡沫分离装置对水中十二烷基苯磺酸钠(SDBS)进行分离富集,考察了表面活性剂溶液的浓度、离子强度、pH值、分离时间、气体流速等因素对水中十二烷基苯磺酸钠脱除率的影响。进一步采用四因素三水平正交实验进行分离条件的优化,结果表明溶液浓度为20 mg/mL,气体流速为20L/min,pH=10,离子强度为2×10-5mol/L时,分离5 min,可使SDBS的脱除率最高达到97%,三次平行试验SDBS的脱除率分别为96.61%、97.04%和93.93%。与单级环流泡沫分离塔(其脱除率为82%)相比,多级泡沫分离装置具有能耗比低、分离效率高的优点,具有更好的推广应用价值。     

表面改性磁种-磁滤技术处理含油废水的研究

将表面改性后的磁粉,磁性颗粒分别作为磁种和磁滤材料,以出水含油量、除油率为试验指标,采用磁种-磁滤技术处理江苏油田废水.试验结果表明,经改性后的Fe3O4磁种粒度小、比表面积大,与油滴的吸附亲和力增强,且包覆在Fe3O4表面的偶联剂能阻止Fe3O4微粒聚结,减缓沉降速度,从而提高除油效果.当进水含油量为140.3mg/L,磁种投加量300mg/L、搅拌强度250r/min,搅拌时间20min、磁滤速度25m/h、磁感应强度0.0839T时,出水含油量降为19.8mg/L,除油率迭85.9%.     

A highly efficient method for concentrating DNA from river water by combined coagulation and foam separation

ABSTRACT

Both Escherichia coli and Enterococci were collected in foam within 7 min from 500 mL of bacteria-spiked water by coagulation and foam separation using ferric chloride and milk casein. These bacterial DNA isolated in the 100 µL of extract from the foam more than 87.5% recovery using the DNeasy PowerWater® Kit. To test this method with water from three natural rivers, 0.67–2.70 µg of DNA were concentrated in 100 µL of extract from 1,000 mL of river water. When the DNA extract was subjected to 16S rRNA gene sequencing analysis, information on the bacterial flora could be obtained.