浸没式膜-生物反应器中污泥浓度对错流速度及传氧速率的影响

研究了浸没式膜-生物反应器中污泥浓度与膜面错流速度以及传氧速率之间的关系。结果表明,污泥浓度的提高使传氧速率系数下降,当污泥浓度从4.5g/L变化至21.5g/L,传氧速率系数从0.565降低至0.155。根据气液反应器理论进行传质分析表明,传氧速率系数的降低主要是由于污泥浓度增大引起了混合液粘度增大所致。同时污泥浓度的上升会导致膜面错流速度的降低,不利于控制膜污染。     

MBR处理黄姜皂素废水膜通量影响膜污染研究

为了解MBR工艺处理黄姜皂素废水的膜污染状况,研究了不同膜通量条件下膜污染的过程和污染物的处理效果,分析了膜污染特性。结果表明,膜通量为4.16 L/(m~2·h)时,不仅能有效控制膜污染,MBR膜的COD的处理效率也较高,更接近生产实际。不同污泥含量与膜污染速率呈现不同的相关关系。当污泥质量浓度9 g/L时,污泥含量对膜污染速率的影响较小;而污泥质量浓度9 g/L时,膜污染速率与污泥浓度呈显著相关。EPS中的多糖和蛋白质、SMP中的多糖对膜污染都有重要贡献。     

聚合氯化铝强化好氧颗粒污泥的形成及污染物去除特性研究

在反应器中分别投加不同质量浓度的聚合氯化铝溶液(分别为0、50、100、400 mg/L废水),作为对照组、低PAC组、中PAC组、高PAC组,培养好氧颗粒污泥。研究发现,培养70天后:除对照组外其余3组均能形成颗粒污泥;随着PAC投加量的增加,4组反应器污泥质量浓度、比重逐渐增高,污泥体积指数、污泥的含水率和不完整性系数逐渐降低;4组反应器的COD去除率分别为95%、98%、98%和98%,氨氮去除率分别为60%、94%、99%和99%,总无机氮去除率分别为58%、84%、79%和78%;投加PAC的3组污泥比好氧速率、硝化速率、反硝化速率均高于对照组,投加PAC的3组中随着PAC投加量的增加,污泥的硝化速率逐渐增高,比好氧速率、反硝化速率逐渐降低。     

喷射环流反应器处理垃圾渗滤液的硝化特性研究

采用喷射环流反应器处理实际垃圾渗滤液，重点研究了系统的氨氮硝化性能，分别考察了游离氨（FA）和游离亚硝酸（FNA）对氨氧化菌（AOB）和亚硝态氮氧化菌（NOB）活性的影响。结果表明，AOB菌群活性在FA质量浓度<6.5 mg/L、FNA质量浓度<0.1 mg/L时不受影响；在FNA质量浓度>0.1 mg/L时受到一定抑制但仍有较大活性。NOB菌群活性在FA质量浓度<3 mg/L且FNA质量浓度<0.01 mg/L时基本不受影响；在FA质量浓度>3 mg/L或FNA质量浓度>0.01 mg/L时受到明显抑制，且抑制作用随FA、FNA浓度升高呈增大趋势。碱度（碱度/氨氮需>7 g/g）对AOB有较大影响，而对NOB基本无影响。喷射环流反应器的氧转移效率可达45%，硝化速率可达0.06 g/（g·d），相较于传统MBR硝化单元具有氧转移效率和硝化效率高、水力停留时间短、占地面积小、能耗低的优点。     

重力自流非织造布-生物反应器处理生活污水

针对膜生物反应器自身造价高的问题,研究开发了一种利用新型非织造布作为过滤组件的一体式MBR,并针对膜生物反应器能耗较高的问题,对该反应器进行了利用生物反应器内液位水头重力自流出水的研究.试验结果表明采用该反应器处理生活污水,反应器平均出水COD＜20 mg/L,氨氮质量浓度＜1.5mg/L,对于3 μm非织造布,重力自流出水条件下,临界通量为10L/(m2·h)左右,在活性污泥浓度为4 000 mg/L左右情况下,合适的曝气量为1.0m3/h,污染后的非织造布经过0.3%的NaClO浸泡清洗,通量可以恢复到新非织造布通量的96%.     

无纺布膜临界通量及其在洗浴废水处理中的应用研究

以无纺布平板膜生物反应器为试验装置,采用通量阶梯式递增法的临界通量进行了测定,研究了混合液污泥浓度(MLSS)对无纺布膜临界通量的影响,考察了膜通量对无纺布平板膜生物反应器长期运行的影响。试验结果表明,无纺布膜的临界通量与MLSS浓度成反比,当MLSS的质量浓度从3 g/L增长到9 g/L时,无纺布膜临界通量从17 L/(m2·h)下降到13 L/(m2·h)。在MLSS的质量浓度控制为5 g/L,膜通量低于临界通量15 L/(m2·h)的条件下,无纺布平板膜生物反应器可连续稳定运行130 d,且反应器出水各项指标均可满足GB/T 18920—2002《城市污水再生利用城市杂用水水质》标准的要求。     

水解+MBR工艺处理印染废水的研究

针对印染废水成分复杂、废水有机物含量高、可生化降解性差的特点,采用了水解 好氧膜生物反应器(MBR)组合工艺,实验考察了反应器的启动,组合工艺对色度、化学耗氧量(COD)及浊度的去除效果。结果表明:组合工艺COD的去除率保持在90%以上,脱色率为82%;水解酸化池提高了废水的可生化性,改变了难降解染料的分子结构,为后续MBR工艺创造了条件;膜生物反应器中活性污泥浓度是影响反应器处理效果和膜通量的因素之一,污泥浓度在(8~15)g/L之间运行较为合适。     

好氧颗粒污泥处理啤酒废水的研究

以葡萄糖模拟废水培养出的好氧颗粒污泥为接种体,通过啤酒废水驯化,考察该污泥处理啤酒废水的可行性。实验结果表明,葡萄糖好氧颗粒污泥经驯化后能够迅速适应这种以糖类有机污染物为主的啤酒废水,驯化前后的污泥形态、生物活性差别不明显,相应的比耗氧速率分别为41.90和39.54g[O2]/(kg[MLSS].h)。驯化后的MLSS的质量浓度为8.23g/L左右,反应器的有机负荷稳定在4.3g[COD]/(L.d),而出水COD的质量浓度保持在45mg/L以下。因此,采用好氧颗粒污泥处理易生化的中低浓度工业废水有良好的应用前景。     

好氧管式膜生物反应器处理高含盐有机废水的研究

采用好氧管式膜生物反应器处理不同含盐浓度的有机废水 ,研究结果表明 (1)进水COD浓度在 2 0 0 0～ 30 0 0mg/L时 ,出水COD在 179～ 2 2 3mg/L之间 ,COD平均去除率在 89.5 %以上 ;(2 )MBR处理高盐度有机废水耐冲击负荷的能力较强 ,出水水质稳定 ;(3)当膜的TMP =0 .1MPa,盐度为 1.0 %、1.5 %、2 .0 %时 ,管式膜的稳定运行通量分别为30、2 4、2 1L/ (m2 ·h) ,整个运行过程中没有进行膜清洗     

一体式膜生物反应器处理某商业楼污水的启动性能

采用一套自行研制的一体式膜生物反应器(MBR)处理浙江某商业楼污水,探讨了其运行启动阶段的工艺特征。结果表明在不排泥工况下,MBR启动迅速且出水在消毒后满足GB/T 18920-2002规定的水质标准;系统中活性污泥增长缓慢,产率仅0.17 mg/mg,其中异养菌活性受到抑制而硝化活性显著上升(比好氧速率分别为7.1、24.5 mg/(g.d);帘式中孔纤维膜组件应用、恒定低通量(5.2 L/(m2.h))出水方式、错流式过滤、混合液较低的COD等工艺条件,使MBR在50 d运行时间内,膜过滤压差和阻力分别在5～8 kPa和1.73～2.27×1011m-1的较低范围内变化,有利于其长期稳定运行。     

单一反应体系曝气量与污泥质量浓度对同步硝化反硝化的影响

利用自培养硝化污泥与实验室筛选的1株反硝化细菌共培养形成共生污泥,构建膜生物反应器(MBR)单一反应体系同步硝化反硝化系统,得到系统良好同步硝化反硝化曝气量和污泥浓度的最优条件。由试验结果可知:在混合污泥质量浓度(MLSS)6.0~10.0 g/L时,调节曝气量,可以使单污泥同步硝化反硝化总氮(TN)去除率达到85%以上。不同MLSS下,达到最高TN去除率的最佳曝气量随着MLSS增高而向高曝气量偏移。随着MLSS增高,响应因子F变小,由曝气量的变化而引起的TN去除率变化明显变缓,表示MLSS对O2传递的缓冲能力越强。在MLSS为8 g/L条件下,低负荷比较容易达到较高的TN去除率,而高负荷下需要更高的曝气量以获得高的TN去除率,系统适合的NH4+-N负荷范围0~0.30 kg/(m3.d)。MLSS≥3.0 g/L,出水化学需氧量(COD)低于50 mg/L,COD大部分贡献于反硝化所需C源。单一反应体系同步硝化反硝化系统能对负荷的改变作出及时的回应,整体上运行比较稳定。     

Critical Review on the Effects of Mixed Liquor Suspended Solids on Membrane Bioreactor Operation

Abstract

One of the characteristics of MBRs is that they typically operate with higher mixed liquor suspended solids (MLSS) concentration than activated sludge with a conventional settling tank. While higher MLSS has obvious benefits in terms of increasing the volumetric loading or the solids retention time, it can have negative impacts on system operation and economics. We critically evaluate three hypotheses on how high MLSS may adversely affect MBR operation:

• (1)?reduced membrane flux with high MLSS,

• (2)?decreased aeration alpha (α) value with high MLSS, and

• (3)?poorer thickening characteristics of excess sludge wasted from an MBR based on the Sludge Volume Index (SVI) and the Capillary Suction Time (CST).

The results support the first and second hypotheses, but not the third. Increasing MLSS decreases the critical permeate flux, but the effect is strong only for MLSS<～5 g/L. For the typical MLSS zone (>～5 g/L), flux‐management techniques to prevent serious cake formation are more important than MLSS. The aeration α decreases with increasing MLSS concentration, although the strength of the correlation depends on system‐specific factors that are poorly understood. Thickening properties of IMBR sludge are not significantly poorer than those of traditional activated sludge, based on available CST tests.     

膜生物反应器处理印染废水的试验研究

通过对印染废水试验研究,使用一体式膜生物反应器(MBR)工艺处理该类废水,采用单因素试验优化工艺参数,并获得最佳工艺参数。试验结果表明,本MBR系统处理印染废水的最佳工艺条件是:污泥浓度5~10 g/L,溶解氧2~4 mg/L,污泥容积负荷0.7~0.8 kg COD/(m3·d),水力停留时间15~20 h,出水的COD去除率在90%上下。     

污泥浓度对MBR净化效果影响试验研究

在不排泥条件下,膜生物反应器(MBR)内的污泥浓度MLSS和MLVSS都随时间不断累积,而反映污泥活性的MLVSS/MLSS则不断减少。研究中发现,MLSS对MBR运行效果影响显著:TN的去除率随污泥浓度增加而增加,而COD的去除率随MLSS的增加先降后升,TP的去除率则先升后降,且二者均在污泥浓度6500 mg/L时达到极值,NH3-N的去除效果则随着污泥负荷的增加呈降低趋势。     

MLSS concentration: Still a poorly understood parameter in MBR filterability

In this paper Membrane Bioreactor (MBR) activated sludge is obtained from full scale MBRs and submitted to cross-flow filtration using always the same membrane and operational conditions. Samples are diluted in order to create suspensions with different Mixed Liquor Suspended Solids (MLSS) concentrations. MLSS values varied between 3.6 and 18.3 g/L. Contrary to literature results filterability did not present a continuous increase with decreasing MLSS concentrations. Activated sludge with MLSS concentration exceeding 10 g/L originated dilution samples with worse filterability. The dilution caused an increase of particles in the range 10 to 20 μm and a decrease in the range 30 to 100 μm. The activated sludge samples had non- Newtonian viscosity and Soluble Microbial Products (SMP) concentrations varied between 60 and 11 mg/L. Activated sludge samples with MLSS concentrations exceeding 10 g/L are entrapping particles smaller than 20 μm in the activated sludge bulk that therefore are not contributing to the increase of resistance on the membrane. Activated sludge samples with lower MLSS concentrations do not show the capability to entrap particles. These different behaviours suggest that are optimal MLSS concentration ranges for MBR operation.     

PAC投加量对MBR混合液性质及膜污染的影响

比较了1g／L及2g／L的PAC投加量对膜生物反应器中混合液性质及膜污染速率的差异。发现两系统上清液COD差距不明显,说明1g／L的PAC投加量忆足以吸附小分子的有机物。当PAC从1g／L增至2g／L时,从微生物絮体中提取的多糖平均值分别为：14．92mg／gMLSS、15．38mg／gMLSS;蛋白质平均值分别为18．82mg／gMLSS、17．58mg／gMLSS;且膜丝内部累积的多糖和蛋白质含量基本相同。当PAC投加量为2g／L时,部分破碎的PAC颗粒会进入膜孔内部,引起不可逆污染。     

Influence of Dissolved Organic Carbon and Suspension Viscosity on Membrane Fouling in Submerged Membrane Bioreactor

Abstract

This paper deals with the membrane fouling in membrane bioreactor (MBR). Based on the experimental data obtained in the MBR pilot plant study, the influence of F/M ratio on the irreversible and reversible fouling was discussed in the wide range of MLSS concentration. In the case of lower MLSS concentration (2,000–3,000 mg/L), irreversible fouling rate of membrane increased with increasing F/M ratio because of the accumulation of DOC in the mixed liquor. It seems that soluble microbial products with the similar size of the membrane pore will be most responsible for the irreversible fouling. In the case of higher MLSS concentration (8,000–12,000 mg/L), reversible fouling rate of membrane increased with increasing F/M ratio because of the increased suspension viscosity caused by the increased activated sludge size or volume even in the same MLSS concentration.     

New configuration of a membrane bioreactor for effective control of membrane fouling and nutrients removal in wastewater treatment

Excess aeration to membrane surface is common for controlling membrane fouling in a submerged membrane bioreactor (MBR) system, but significant energy is consumed for excess air production. Therefore, an alternative strategy for membrane fouling control is currently needed. A new configuration of MBR was proposed in this study to control membrane fouling effectively. To reduce biosolids concentration near the membrane surface, the position of the membrane module in MBR was elevated from the bottom to the top in the reactor. This could divide the reactor to two different zones: upper and lower zone. Air was not supplied at the lower zone whereas aeration was given to the upper zone where the membrane filtration was carried out. Biosolids concentration was reduced in the upper zone because the mixed liquor was settled down to the lower zone. Membrane fouling could be lessened in the upper zone due to the reduced biosolids concentration. Therefore, to verify if this new configuration of MBR could mitigate membrane fouling, the effect of changing vertical position of the membrane module in MBR on membrane fouling was investigated. Prior to verification the effect of elevation of membrane module on membrane fouling, influence of MLSS concentration on membrane fouling was investigated first. Transmembrane pressure (TMP) increase became steep as MLSS concentration increased. And the immersed membrane module was elevated from the bottom to the top of the MBR. When the upper membrane was located in the bioreactor, less membrane fouling was observed. This could demonstrate a possibility of new MBR design to control membrane fouling. In addition, reduced dissolved oxygen level in the returned sludge to anoxic tank could increase denitrification efficiency if this configuration is directly applied to biological nutrient removal processes.     

Mathematical modeling of aerobic membrane bioreactor (MBR) using activated sludge model no. 1 (ASM1)

Activated sludge model no. 1 (ASM1) was applied to an aerobic membrane bioreactor (MBR) treating dilute municipal wastewater. The model for the aerobic MBR was calibrated using the data collected from a lab-scale aerobic MBR using AQUASIM 2.0. The performance of MBR process in terms of chemical oxygen demand (COD) removal and ammonia nitrogen (SNH) nitrification was studied at different operating conditions such as hydraulic retention time (HRT), solid retention time (SRT) and mixed liquor suspended solids (MLSS) concentrations. The characteristics of influent wastewater, pre-settled primary effluent from a wastewater treatment plant (City of Elmhurst WWTP, Elmhurst, IL, USA), were determined in the laboratory and used for the calibration of the model. The results from the simulations provided a better understanding of the mechanisms and kinetics of the MBR process including sludge removal.