Flat-plate submerged membrane bioreactor for the treatment of higher-load graywater

Graywater treatment has been the focus when topics of decentralized treatment systems are discussed. In this paper, the treatment of higher-load graywater, a mixture of washing machine and kitchen sink wastewater, was investigated. A 10 L lab-scale submerged membrane bioreactor (subMBR) was operated with a flat-plate membrane for 87 days. Permeate was intermittently withdrawn at constant transmembrane pressure (TMP) induced by water level difference and without pump requirement. The pollutants' removal and membrane behavior were monitored. The COD removal was around 96% and a permeate COD of about 26 mg L^− 1 was obtained. The total linear alkylbenzene sulfonate (LAS) removal achieved was > 99%, indicative of its non-inhibited degradation even at influent concentration of 30.8 mg L^− 1. The subMBR was operated at almost stable and constant flux of 0.22 m³ m^− 2 d^− 1 at a mean HRT of 13.6 h.     

超滤膜对海上天然气平台生产水的深度处理试验

采用国产超滤膜对南海某海上天然气平台的生产水进行深度处理应用试验,研究了其对平台生产水水质的适用性,以及超滤膜的过滤性能和超滤膜设备长周期稳定运行规律。结果表明,超滤膜设备累计运行超过408 h性能无衰减,其各项工艺参数始终保持稳定,产水油质量浓度均低于20 mg/L。超滤膜材料及设备具有很好的抗污染性能和长周期稳定运行能力,其产水水质满足一级海域排放限值。     

稠油油田采出水处理工艺研究与应用

鲁克沁油田是一个注水开发的稠油油田,随着油井注水受效比例增大,提液增产工作量增加,采出水量呈不断上升趋势。为实现油田经济、有效注水,减轻环境污染,降低油田开发成本,进行了采出水生化处理后回注工艺的研究与应用。在采出水处理工艺上,优选"倍加清"4号、7号联合生物菌群,对有机质平均去除率达到96%;进行加药方案优化研究,确定了絮凝剂、除氧剂、杀菌剂等最佳加药方案,现场采出水经处理后,悬浮物、粒径中值、含油、细菌等水质主要控制指标均达标,同时系统运行平稳,实现了合格污水回注。另外,在室内分别进行了注清水和污水后对储层的伤害情况进行研究,确定了清污混注时的最佳混配比,为油田下步清污混注奠定了技术基础。     

Viability of microbial mass in a submerged membrane bioreactor

In this study the viability of biomass in a submerged membrane activated sludge system (sMBR) which treats domestic wastewater was investigated by dealing with non-biodegradable COD, specific oxygen uptake rate and MLVSS during operation for 100 days. It was shown that the viability of biomass in the bioreactor was reduced at the 50% level because of the accumulation of inert compounds and the reduction in the activities of poor biomass. After inoculating the bioreactor again, the specific OUR increased because of young biomass entering into the bioreactor. It was shown that there was an exponential relationship between OUR and MLVSS and there was a logarithmic relationship between specific OUR and MLVSS.     

膜蒸馏处理页岩气田采出水的研究进展

综述了膜蒸馏技术在页岩气采出水领域的研究现状,重点介绍了不同的膜蒸馏形式(直接接触式膜蒸馏、真空膜蒸馏、气隙式膜蒸馏、集成膜蒸馏工艺)处理页岩气采出水的研究进展,以及可适用于页岩气采出水处理的新型超疏/双疏膜的制备方法(静电纺丝法、表面涂覆法、化学改性法)的研究现状.     

浸没式厌氧双轴旋转膜生物反应器的膜污染特性研究

试验研究了浸没式厌氧双轴旋转膜生物反应器处理啤酒废水时膜的污染特性.试验分析了膜阻力分布和膜污染速率及稳定运行时膜过滤阻力随运行时间变化的阻力模型.结果表明,膜表面滤饼层很薄,膜污染很轻,膜污染速率很小.结果表明系统由膜组件双轴旋转而形成的良好水力学条件,能有效地减小浓差极化和避免污泥颗粒在膜表面的沉积.可有效控制膜污染.     

Experimental investigation of oily water treatment by membrane bioreactor

In this study a membrane bioreactor (MBR) has been studied experimentally for the treatment of oil field wastewater (produced water). This type of wastewater is characterised with relativity moderate to high amount of salt and oil. The normal bacteria which are growing in conventional activated sludge and MBR cannot withstand at these adverse conditions, therefore it is necessary to be adapted.In this study, different samples from sea sediment in Bushehr (south of Iran) were analysed and different groups of bacteria were isolated and adapted for surveying under high salinity conditions. The performance and efficiency of these bacteria in the degradation of model oil has been studied. The results showed that the bacterial consortium can degrade two models of hydrocarbons (hexadecane and phenanthrene) in the presence of salt very effectively.The adapted bacteria were cultivated later in the feed tank of a submerged hollow fiber MBR. The performance of the system, membrane permeability and the rate and extent of oil biodegradability have been studied under different operating conditions. The results showed that the MBR system could be very effective in the removing of oil from produced water.     

气田采出水复合除铁、除钙工艺

由预处理环节水质及精馏塔垢分析可知,管线堵塞的主要原因是含铁、含钙量严重超标,导致结垢物堆积在输水设备及管线内部,同时引起垢下腐蚀,影响气田采出水处理设备的正常运行。鉴于绝大多数处理厂仅考虑铁离子的去除,而未考虑Ca²⁺的去除,本文首次在采出水预处理环节对除铁和除钙工艺进行复合,通过筛选适宜的除铁除钙剂,优化加药顺序、加药反应时间、静置时间等参数,开发出适用于气田采出水处理的复合除铁除钙工艺。结果表明,现场加药量为H₂O₂ 500mg/L、NaOH 500mg/L、PAC 50mg/L、PAM 4mg/L,除钙剂与Ca²⁺的摩尔比为1∶1,加药顺序为Na₂CO₃→H₂O₂→NaOH→PAC→PAM,反应时间7min以上,静置5h以上时,气田采出水中的总铁离子含量可由153.24mg/L降至0.3338mg/L,Ca²⁺由5495mg/L降至520mg/L,其中总铁离子降幅为99.8%,Ca²⁺降低了90.54%,矿化度大幅度降低可避免后续环节堵塞,从而保障气田采出水处理系统高效运行。     

A comparison of submerged and sidestream tubular membrane bioreactor configurations

This paper provides an improved understanding of the effect of sidestream (SS) and submerged (Sub) MBR configurations on hydraulic and biological system performance for a tubular membrane geometry. Effects of key flow parameters, these being aeration rate (U_G) in the Sub MBR and cross flow velocity (CFV) in the SS MBR, on fouling behaviour have been assessed during short-term flux-step experiments. Both synthetic and real sewage feeds have been used. Series of tests carried out with both feeds indicate the similar fouling behaviour observed for Sub and SS MBRs operated at U_G of 0.07-0.11 m s⁻¹ and CFV of 0.25-0.55 m s⁻¹ respectively. Analysis of the TMP-based parameters determined from the flux-step experiments show the effect of U_G in Sub configuration to be greater than those of CFV in SS MBR, and to be more efficient at higher fluxes (up to 97% decrease in fouling rate for U_G increased from 0.02 to 0.2 m s⁻¹, at 291 m⁻² h⁻¹). The influence of MBR configuration on biomass characteristics was also assessed by acclimatising the biomass at three MLSS concentrations for both configurations and revealed the carbohydrate contained in the biomass supernatant to be a possible indicator of fouling for MBR operation.     

填料对一体式膜生物反应器运行效能的影响

进行了组合式膜生物反应器(CMBR)和一体式膜生物反应器(SMBR)处理生活污水的试验研究,以考察填料对处理效果的影响及减缓膜污染方面的作用。在稳定期,CMBR对COD的平均去除率为96.7%,SMBR为95.9%,对NH3—N的去除率分别为95.6%和94.9%,试验结果表明,填料的添加对反应器COD和NH3—N的去除效果影响不大,但能有效增强反应器对总氮的去除,去除率从54.5%提高到67.5%;经102 d连续运行,CMBR膜组件清洗次数少于SMBR,说明添加填料不仅提高了膜生物反应器(MBR)的处理效果,而且相对有效地减缓了膜阻力升高的速度;单位膜面积上胞外聚合物(EPS)的面密度与2个膜生物反应器过膜压力随运行时间的变化规律基本一致,CMBR和SMBR中膜阻力与单位膜面积上EPS的面密度正相关,证明EPS对膜污染有着重要的影响。     

Performance evaluation of modified fabricated cotton membrane for oil/water separation and heavy metal ions removal

Preparation of effective membrane with special surface treatment for oil/water separation having promising future and low manufacturing cost. The suggested membrane was fabricated by a simple treatment via increasing the hydrophilicity of the cotton fabric surface. The cotton fabric was impregnated in poly(acrylic acid-co-N-methylol acrylamide), poly(AA-co-NMA), where NMA acts as bonding agent. Sodium hypophosphite (SHP) was added to the modification solution to enhance the bonding between the cotton fabric and the PAA. The modified fabric was thermally dried and cured at different temperatures. It was found that, the presence of 3.5% NMA and addition of 5% SHP to the modification solution then curing at 190°C gave the highest amount of bonded PAA to the cotton fabric. The success of the modification process was confirmed by scanning electron microscope, Fourier transformer infrared and the increase in the contact angle of the cotton fabric after modification. Furthermore, the prepared membrane was evaluated for oil (n-hexane, toluene, and petroleum ether)/water separation and also for heavy metal ions removal (Cd²⁺ and Co²⁺). Neutralization of the produced membrane with ammonium hydroxide resulting in a higher contact angle and consequently higher separation efficiency for oil/water mixtures and higher performance for heavy metal ions removal compared to the unneutralized one.     

Enzyme hydrolysis of babassu oil in a membrane bioreactor

This work deals with the enzymatic hydrolysis of babassu oil by immobilized lipase in a membrane bioreactor using unmixed aqueous and lipid streams. The experimental work was carried out in a flat plate membrane module with two different membranes: hydrophobic (nylon) and hydrophilic [mixed cellulose esters (MCE)], with different nominal pore sizes ranging from 0.10 to 0.65 μm. Candida cylindracea lipase was adsorbed on the membrane surface area, and the reactor was operated in batch mode. The initial enzymatic rate increased from 80 to 150 μmol H⁺/min when the organic phase velocity increased from 1.0×10⁻³ to 3.0×10⁻³ m/s, indicating that mass transfer in that phase was the process-limiting step. Calcium ions had a marked effect on immobilized lipase activity, increasing around twofold the lipolytic activity. Long-term experimental runs showed that the immobilized lipase remained stable for at least 8 d. The values for immobilized protein and maximal productivities observed for 0.45 μm membranes were: 1.01 g/m² and 193 μmol H⁺/m²·s for MCE membrane and 0.78 g/m² and 220 μmol H⁺/m²·s for nylon membrane. The productivities obtained are among the highest values reported in the technical literature.     

Effect of operational parameters on sludge accumulation on membrane surfaces in a submerged membrane bioreactor

In the present study, an orthogonal array design was adopted to investigate effects of operational parameters including aeration intensity, membrane flux, suction time and non-suction time on sludge accumulation on membrane surfaces respectively at a high SS concentration of 10 g l⁻¹ and a low SS concentration of 1 g l⁻¹ in a submerged membrane bioreactor. Average transmembrane pressure (TMP) increase rate over the operation time was used to evaluate sludge accumulation. Among the four factors, membrane flux was found to influence TMP the most obviously. The effect of aeration intensity became significant only at a high SS concentration of 10 g l⁻¹. TMP increased with suction time and decreased with non-suction time. There was a critical membrane flux over which sludge particles were deposited, and accordingly, TMP increased sharply. Two zones, predicting whether sludge particles are deposited or not, could be comprehensively determined by the critical flux, correspondent aeration intensity and SS concentration. For long-term stable operation, it is suggested that a membrane bioreactor be operated in the zone with prediction of no obvious sludge deposit on membrane surfaces.     

两种膜生物反应器工艺在养殖废水处理中的运行效果

采用动态膜生物反应器（dynamic membrane bioreactor,DMBR）和膜生物反应器（membrane bioreactor,MBR）两种处理工艺,研究在相同条件下对养殖废水的处理效果和运行条件。结果表明,不同溶解氧（dissolve oxygen,DO）条件下,DMBR和MBR对CODMn的去除率可达95%以上。DO为0～1 mg/L条件下,DMBR和MBR的总氮平均去除率分别达到71.4%、75.8%;在DO为2～3 mg/L条件下,DMBR和MBR的总氮平均去除率分别为46.3%、44.1%。DMBR和MBR两种工艺均能达到较好的污染物去除效果。MBR的过滤压差明显高于DMBR,低DO条件下（0～1 mg/L）的运行周期约为5天,DMBR采用重力流出水,运行周期约为10天,过滤压差最高时仅为3.97 kPa,在一定程度上克服MBR成本高、易污染等缺点。     

Performance of a compact submerged membrane sequencing batch reactor (SM-SBR) for greywater treatment

A long-term study was carried out to evaluate the performance of submerged membrane sequencing batch reactors (SM-SBR) for greywater treatment. Three pilot plants were operated in three different countries with distinct wastewaters to prove that treated greywater can be used for reuse purposes.In all plants the permeate quality fulfilled in most cases the high mandatory values of different European directives. Membrane permeability declined significantly within a period of three to four months so that recovery cleanings were necessary 3 to 4 times a year. In general, the treated greywater from an SM-SBR can be reused for irrigation or cleaning purposes. SM-SBR for greywater treatment are especially interesting in cases of space limitations where the small footprint of the system can outweigh inconveniences like frequent chemical cleanings.     

聚合物驱油田采出水处理工艺新技术

在传统油田采出水处理工艺技术的基础上,设计了创新工艺,增加了预处理工艺流程和处理设备,将水力旋流配合速沉器的工艺作为精细过滤的前处理工艺,其工艺流程为:来水→水力旋流除油→速沉器→精细过滤→出水。经该工艺处理后,出水含油质量浓度平均为1.34 mg/L,出水悬浮物固体质量浓度为3.77 mg/L,粒径中值达1.419μm,含油量达标率100%,悬浮物达标率100%。     

Development of the wastewater reclamation and reusing system with a submerged membrane bioreactor combined bio-filtration

Recently there have been many wastewater treatment processes combining different units of process to improve the dissolving and suspension of pollutants in water. The submerged membrane bioreactor (SMBR) system uses a membrane that can produce high quality water for reusing with minimal land demand, instead of using secondary clarifier as biological treatment, sand filters, ozonation, GAC or disinfection processes as a tertiary treatment. For the development of the bio-filter membrane bioreactor (BMB) system as a submerged membrane bioreactor in this study the new wastewater treatment system will consist of a rapid bio-filter clarifier, a bioreactor and a hollow fiber membrane and plate membrane, to help find the optimal process to meet the regulations for reused water. This study was performed to evaluate the BMB reusing system, made up of a rapid bio-filter clarifier, an activated sludge bioreactor and a membrane module. The rapid bio-filter clarifier replaced a conventional primary sedimentation and removed SS, BOD and COD to 40, 20, and 20%, while the turbidity and color were removed by 30 and 10% respectively. This means that the rapid bio-filter clarifier having an HRT value 5.2 min can replace the conventional primary sedimentation of the HRT value of 1.5–2.5 h. Also the BMB reusing system could achieve the effluent quality of BOD < 5 mg/L, COD < 10 mg/L, turbidity < 0.5 NTU, and color < 20 unit respectively, and total coliforms did not appear. This means this system can meet water quality standard for water reusing systems. The flux of the plate membrane and hollow Fiber membrane were 120–140 L/m² h bar and 60–90 L/m² h bar; much more water could permeate the plate type membrane than hollow fiber type membrane. Plus the total resistance of hollow fiber type membrane was higher than plate type membrane.     

Nitrification and sludge characteristics in a submerged membrane bioreactor on synthetic inorganic wastewater

A submerged membrane bioreactor (SMBR) treating ammonia-bearing synthetic inorganic wastewater withoutsludge purge was studied in respect to nitrification and microbial parameters over a period of 210 days. The reactor was operated at a hydraulic retention time (HRT) of 24 h, and the NH_4-N volumetric loading rate increased from 0.18 to 1.30 kg NH₄⁺-N m⁻³d⁻¹ by increasing influent NH₄⁺-N from 180 mg/l⁻¹ to 1300 mg/l⁻¹. With the exception of a short period after the failure of pH control, the NH₄⁺-N⁺ removal rate, was constantly above 99%. Due to the influent characteristics and the interception of the membrane module, the mixed liquor suspended solids (MLSS) varied from 3000 to 5000 mg/l⁻¹ and the nitrifying bacteria were dominant in the SMBR. The numbers of ammonia oxidizers and nitrite oxidizers in the mixed liquor increased from 0.9×10⁸ ml⁻¹ and 1.0×10⁸ ml to 1.6×10⁸ ml⁻¹ and 9×10⁸ ml⁻¹ respectively, and the specific nitrification rate from 0.27 to 0.56 g NH₄⁺-N g⁻¹ SS⁻¹ d⁻¹. An increasing occurrence of extracellular polymeric substances (EPS) around microbial clusters with operation time was clearly observed on scanning electron micrographs (SEM). The pressure difference of the membrane module was not over 0.01 mPa over the whole operation period. Present results show that SMBR can be operated efficiently and stably as a high-rate nitrifying technology.