Zeolite powder addition to improve the performance of submerged gravitation-filtration membrane bioreactor

In this study, the effect of zeolite powder addition on submerged membrane bioreactor （SMBR） on membrane permeability, and the removals for COD, NH3-N, TN were investigated. Through the parallel operation of control and test systems, it was found that the zeolite powder addition could alleviate the ultra-filtration membrane fouling and enhance the membrane permeability. On the basis of experimental investigations, a concept of ＂protection coating layer＂ was proposed to illustrate the phenomenon of UF membrane fouling. In addition, the removal for COD in test system was more stable, a little higher compared to the control system. Due to the combination of nitrification and ion exchange, a more excellent removal for NH3-N in test system was obtained regardless of influent NH3-N loading rate. It was also found that a mean 25% higher TN removal took place in the test system, and ion exchange and simultaneous nitrification and de-nitrification were analyzed to be main factors. During the stable operation period, the SOURs of test zeolite powder added sludge and control activated sludge were measured to be 75 mgO2/（gMLVSS, h） and 24 mgO2/（gMLVSS, h） respectively, it meant that the zeolite powder addition could enhance the microorganism activity significantly.

Bacterial diversity in activated sludge from a consecutively aerated submerged membrane bioreactor treating domestic wastewater

The bacterial diversity of activated sludge from submerged membrane bioreactor (SMBR) was investigated. A 16S rDNA clone library was generated, and 150 clones were screened using restriction fragment length polymorphism (RFLP). Of the screened clones, almost full-length 16S rDNA sequences of 64 clones were sequenced. Phylogenetic tree was constructed with a database containing clone sequences from this study and bacterial rDNA sequences from NCBI for identification purposes. The 90.6% of the clones were a?l...

Simultaneous nitrogen and phosphor removal in an aerobic submerged membrane bioreactor

Simultaneous nitrification and denitrification （SND） effect and phosphor removal were investigated in a one-staged aerobic submerged membrane bioreactor on pilot-scale with mixed liquor suspended solids （MLSS） 19--20 g/L. The effects of DO concentration, sludge floc size distribution on SND were studied. Test results suggested that SND was successfully performed in the membrane bioreactor （MBR） and about 70% total nitrogen removal efficiency was achieved when DO concentration was set to 0.2-- 0.3 mg/L. The main mechanisms governing SND were the suitable sludge floc size and the low DO concentration which was caused by low oxygen transfer rate with such a high MLSS concentration in the MBR. In the meantime, phosphor removal was also studied with polymer ferric sulfate （PFS） addition and 14 mg/L dosage of PFS was proper for the MBR to remove phosphor. PFS addition also benefited the MBR operation owing to its reduction of extracellular polymer substances （EPS） of mixed liquor.

Enhancement of the flux for polypropylene hollow fiber membrane in a submerged membrane-bioreactor by surface modification

To improve its limiting flux and antifouling characteristics in a submerged membrane-bioreactor （SMBR） for wastewater treatment, polypropylene hollow fiber microporous membrane （PPHFMM） was surface-modified by the plasma-induced immobilization of poly （N-vinyl-2-pyrrolidone） （PVP） and the plasma treatment with different gases respectively. Attenuated total reflection-Fourier transform infrared spectroscopy （FT-IR/ATR）, X-ray photoelectron spectroscopy （XPS） and field emission scanning electron microscope （FE-SEM） were used to characterize the structural and morphological changes on the membrane surface. Water contact angle was measured by the sessile drop method. It was found that the water contact angle was 128.8, 72.3, 62.7, 74.4, 79.1, 86.3, and 71.3° for the nascent, PVP-immobilized, air, 02, Ar, CO2 and H2O plasma treated PPHFMM, respectively. The SMBR was operated at fixed transmembrane pressure to determine the limiting flux for the PPHFMM before and after surface modification. Results showed that the limiting flux appeared to be 103, 159, 117, 133, 136, 121 and 152 L/（m^2· h） for the nascent, PVP-immobilized, air, O2, At, CO2 and H2O plasma treated PPHFMM, respectively. After continuous operation for about 50 h in the SMBR, the antifouling characteristics were improved to some extent.

Rgwo performances of submerged membrane bioreactor treating brewery wastewater: A laboratory study

Performances of submerged membrane bioreactor （SMBR） treating brewery wastewater were investigated in this study. With little variation of COD：TN：TP ratio （100：5：1） in influent, SMBR showed high removal efficiency （ 〉 90% ） for both COD and NH4^＋ - N, and it also showed a strong resistive ability for shock organics loading rate, evidenced by no obvious fluctuation for COD in the effluent when the organics loading rate suddenly increased from 0. 27 g/（ gMLSS · d） to 0. 54 g/（ gMLSS · d）. Comparatively different with the COD removal, TN and TP removal showed a strong correlation with the growth stage of the sludge in SMBR. When the sludge was in the multiplication stage, about 45% of TN was removed and an average removal efficiency of 30% for TP was also observed. However, when the activated sludge was in the steady stage, the removal efficiency for TN decreased to about 30% , whereas, the removal efficiency for TP was very low, and sometimes even below zero. The results of GC/MS indicated that the residual organic matters in the effluent were mainly alkyl hydrocarbon with high molecular weight, and coupling with the results of electroseopic scanning, it is speculated that biomass formed at external and internal membrane fibers played an important role for the removal of small organics.

Treatment of Chinese traditional medicine wastewater in a submerged membrane bioreactor

A pilot scale test was conducted in a submerged membrane bioreactor SMBR with capacity of 10. 0 m^3/d for 120 days to treat high-strength Chinese traditional medicine wastewater. Performance of the SMBR was investigated with a sludge retention time （ TSR ） of 50 days, a hydraulic retention time （ THR ） of 8.0 h, membrane flux of 8. 0 IV（ m^2 · h） and dissolved oxygen （DO） concentration of 2. 0 - 3. 0 mg/L, respectively. It was observed that the SMBR had high capacity of COD and suspended solid （SS） removal. The influent COD concentration was fluctuated between I 000 and 5 000 mg/L, while the averaged effluent COl） concentration was only 44. 6 mg/L. The influent SS concentration was fluctuated between 1 000 and 1 600 mg/L, while little effluent SS was detected. It was found that the COD remove rate increased with mixed liquor suspended solids （MLSS） and organic loading rate （ROL）. In order to obtain good-quality effluent, the operational conditions of the SMBR were suggested as follows： the temperature was controlled above 10 ℃, MLSS about 7000 mg/L, R,L under 24. 76 kg/（ m^3 · d）, low vacuum value and constant water flux.

Feasibility and simulation model of a pilot scale membrane bioreactor for wastewater treatment and reuse from Chinese traditional medicine

The lack and pollution of water resource make wastewater reuse necessary. The pilot scale long-term tests for submerged membrane bioreactor were conducted to treat the effluents of anaerobic or aerobic treatment process for the high-strength Chinese traditional medicine wastewater. This article was focused on the feasibility of the wastewater treatment and reuse at shorter hydraulic retention time （HRT） of 5.0, 3.2 and 2.13 h. MLSS growth, membrane flux, vacuum values and chemical cleaning periods were also investigated. The experimental results of treating two-phase anaerobic treatment effluent demonstrated that the CODfilt was less than 100 mg/L when the influent COD was between 500-10000 mg/L at HRT of 5.0 h, which could satisfy the normal discharged standard in China. The experimental results to treat cross flow aerobic reactor effluent demonstrated that the average value of CODfilt was 17.28 mg/L when the average value of influent COD was 192.84 mg/L at HRT of 2.13 h during 106 d, which could completely meet the normal standard for water reuse. The maximum MLSS and MLVSS reached 24000 and 14500 mg/L at HRT of 3.2 h respectively. Membrane flux had maximal resume degrees of 94.7% at vacuum value of 0.02 MPa after cleaning. Chemical cleaning periods of membrane module were 150 d. A simulation model of operational parameters was also established based on the theory of back propagation neural network and linear regression of traditional mathematical model. The simulation model showed that the optimum operational parameters were suggested as follows： HRT was 5.0 h, SRT was 100 d, the range of COD loading rate was between 10.664-20.451 kg/（m3.d）, the range of MLSS was between 7543-13694 mg/L.

Effect of Intermittent Aeration on the Treatment Performance in a Submerged Membrane Bioreactor

In order to improve removal for nitrogen in a pilot-scale submerged membrane bioreactor（SMBR）,intermittent aeration was conducted,and the effect on the treatment performance under four kinds of operation condition（run 1,continuous aeration;run 2,60/60 min aeration on/off time;run 3,60/90 min aeration on/off time;run 4,60/75 min aeration on/off time） was evaluated.The results showed that depending on the specific on/off of the aeration time ratio,removal efficiency of nitrogen could be improved significantly,and the removal rates of total nitrogen（TN） under different operation conditions were 28.0%,59.5%,66.8% and 70.7%,respectively.There were no obvious differences for removal rates for CODCr and ammonia among different operation conditions.In general,intermittent aeration could be used as a feasible way to improve treatment performance for nitrogen in the SMBR.

Investigation on removal pathways of Di 2-ethyl hexyl phthalate from synthetic municipal wastewater using a submerged membrane bioreactor

Highly hydrophobic Di 2-ethyl hexyl phthalate（DEHP） is one of the most prevalent plasticizers in wastewaters. Since its half-life in biological treatment is around 25 days, it can be used as an efficiency indicator of wastewater treatment plant for the removal of hydrophobic emerging contaminants. In this study, the performance of submerged membrane bioreactor was monitored to understand the effect of DEHP on the growth of aerobic microorganisms. The data showed that the chemical oxygen demand（COD）and ammonia concentration were detected below 10 and 1.0 mg/L, respectively for operating conditions of hydraulic retention time（HRT） = 4 and 6 hr, sludge retention time（SRT） = 140 day and sludge concentration between 11.5 and 15.8 g volatile solid（VS）/L. The removal efficiency of DEHP under these conditions was higher and ranged between 91% and 98%. Results also showed that the removal efficiency of DEHP in biological treatment depended on the concentration of sludge, as adsorption is the main mechanism of its removal. For the submerged membrane bioreactor, the pore size is the pivotal factor for DEHP removal, since it determines the amount of soluble microbial products coming out of the process. Highly assimilated microorganisms increase the biodegradation rate, as 74% of inlet DEHP was biodegraded; however, the concentration of DEHP inside sludge was beyond the discharge limit. Understanding the fate of DEHP in membrane bioreactor,which is one of the most promising and futuristic treatment process could provide replacement for conventional processes to satisfy the future stricter regulations on emerging contaminants.

A fouling suppression system in submerged membrane bioreactors using dielectrophoretic forces

A novel method was developed to suppress membrane fouling in submerged membrane bioreactors. The method is based on the dielectrophoretic （DEP） motion of particles in an inhomogeneous electrical field. Using a real sample ofbiomass as feed, the fouling-suppression performance using DEP with different electrical field intensities （60-160 V） and different frequencies （50-1000 Hz） was investigated. The fouling-suppression performance was found to relate closely with the intensity and frequency of the electrical field. A stronger electrical field was found to better recover the filtrate flux. This is because of a stronger DEP force acting on the biomass par[ides close to the membrane＇s surface. Above an intensity and frequency value of 130 V and 1 kHz, respectively the permeate flux was reduced due to an electrothermal effect.

Performance of Submerged Membrane Bioreactor for Domestic Wastewater Treatment

In the present research, a submerged membrane bioreactor was tested to treat domestic wastewater. Three experimental runs were conducted all with a hydraulic retention time of 5h and sludge retention times (SRTs) of 5, 10, and 20 d. The pollutant removal performance of the membrane bioreactor, the membrane effluent quality, and a kinetic model for sludge growth in the bioreactor were investigated. The combined process was capable of removing over 90% of both COD (chemical oxygen demand) and NH 3 N on the average. The total removal for COD was almost independent of SRT, but that for NH 3 N improved with increasing SRT. Membrane effluent quality meets the water quality standard for reuse issued by the Ministry of Construction of China. Increasing SRT causes the concentrations of suspended solids (SS) and volatile suspended solids (VSS) in the bioreactor to increase. However, the ratio of VSS/SS did not change much. Kinetic analysis showed that the sludge yield coefficient (kg VSS·kg COD -1 ) and the endogenous coefficient of microorganisms were 0.25 and 0.04d -1 , which are similar to those of the conventional activated sludge process.

淹没复合式膜生物反应器技术

综述了膜生物反应器技术进展并分析、阐述了其优缺点 ,提出了新型的淹没复合式膜生物反应器 (SHM BR)以及用于污水处理和回用的工艺 ,从水处理工艺学、流体力学、水微生物学方面论述了其所具有的特点 ,说明了淹没复合式膜生物反应器是一种高效、低耗、资源化的污水生物反应器 ,指出了今后需研究的问题。

一体式膜生物反应器处理生活污水的试验研究

采用一体式聚丙烯中空纤维膜生物反应器处理模拟生活污水,考察了其处理效果,研究了运行条件对膜污染的影响和不同清洗方法对受污染膜的清洗效果。结果表明,在进水COD为172～331 mg/L、NH3-N为23～27 mg/L的条件下,稳定运行时系统对COD和NH3-N的去除率均大于90%。抽停比越小则膜通量的衰减越缓慢;抽吸压力越大则初始膜通量越大;试验中确定的最佳抽停比为8∶2,临界抽吸压力为30 kPa。对已污染的膜采用空曝气、水洗、水洗+碱洗、水洗+酸洗、水洗+碱洗+酸洗的方法进行清洗,可使膜通量分别恢复至新膜通量的30%、46.3%、86.54%、82.36%、92%。

胞外聚合物对浸没式膜-生物反应器膜过滤性能的影响

通过浸没式膜-生物反应器(SMBR)处理上海市城市内河水的试验,研究了反应器混合液中和2种疏水性不同的膜上污泥胞外聚合物(EPS)的量、组成、污泥特性及对膜过滤性能的影响.结果表明,混合液污泥中的溶解性EPS和固着性EPS比膜上污泥多,不同污泥的固着性EPS组分中蛋白质(EPSP)/多糖(EPSC)的大小顺序依次为混合液污泥<亲水膜污泥<疏水膜污泥.疏水膜污泥中溶解性EPS比亲水膜多,溶解性EPS和固着性EPS量及组分均有很大差异.混合液污泥的EPS流动性大,疏水性膜上污泥EPS的流动性较大.溶解性EPS对污泥特性及膜过滤性能影响较大.SMBR中亲、疏水性膜片上黏附的污泥的相对疏水性分别为53%、59%.比较2种膜片通量的变化发现,疏水性膜污染严重.

溶解性微生物产物对浸没式膜生物反应器运行的影响

对溶解性微生物产物(SMP)的累积行为及其对浸没式膜生物反应器(SMBR)操作运行的影响进行了研究.在90 d的实验过程中,对总有机碳(TOC)、相对分子质量分布(MWDs)、比耗氧速率(SOUR)进行定期监测,采用死端过滤实验来检测SMP对膜污染的影响.结果表明,在SMBR上清液中SMP出现明显累积;随着实验运行,SMP中相对分子质量大于10 000的浓度增加显著;与相对分子质量小于1 000的SMP相比,此部分SMP对污泥活性和膜污染影响较大,对SMBR的出水水质影响较小.

淹没式复合型MBR处理城市生活污水的效能研究

为了缓解缺水压力,在传统膜生物反应器(CMBR)的基础上开发出了一种新型城市污水处理回用工艺——淹没式复合型膜生物反应器(SHMBR),并考察了对城市生活污水的处理效果。试验结果表明,SHMBR可以在CMBR的基础上进一步提高生物量,并明显改善了对有机物和NH4+-N的去除效果。试验中对TN、TP的去除效果没有提高,原因可能是生物膜的厚度不够,没有在生物膜内部形成厌氧微环境。另外,SHMBR的除磷效果没有增强还可能与生物膜的SRT较长以及聚磷菌主要生活在活性污泥中有关。

胞外聚合物对一体式膜生物反应器过滤特性的影响

考察一体式膜生物反应器(SMBR)运行中胞外聚合物(EPS)含量与膜过滤特性的关系,实验结果表明:EPS在反应器和膜表面均积累,引起混合液粘度和过滤阻力的增加;膜表面吸附的EPS质量随着悬浮EPS浓度变化而变化;周期性排放污泥可减少反应器内悬浮EPS浓度和膜表面EPS含量,从而降低膜的过滤阻力;膜生物反应器中悬浮EPS浓度与过滤阻力之间的相关性方程为:R=7×10~5×P^(3.3385)_v;单位膜面积吸附EPS质量与过滤阻力之间的相关性方程为:R=3.1525×10^(13)×P_u-2.201×10^(12)。

投加粉末活性炭对一体式膜-生物反应器膜污染的影响研究

通过试验考察了粉末活性炭(PAC)对一体式膜-生物反应器中膜污染的影响.在2种类型的污泥(膨胀污泥和非膨胀)中,投加适量PAC可以减轻膜污染,表现为临界膜通量的提高和连续运行中膜污染增长速率的降低.当污泥性质和浓度不同时,最佳PAC投加范围亦不同.PAC投量过大会引起临界通量下降.PAC的投加显著降低了混合液中溶解性物质的浓度,减轻了溶解性物质的吸附和膜孔堵塞污染,并改善了絮体结构.污泥比阻与污泥混合液膜过滤性能之间有很好的相关性,可作为污泥混合液膜过滤性能的快速评价指标.

淹没式MBR处理啤酒废水的净化效能

在投加营养物质 ,保持COD∶TN∶TP =10 0∶5∶1的条件下 ,淹没式MBR对合成啤酒废水中的COD、NH+ 4 N有着较好的去除效果 ,系统稳定时COD与NH+ 4 N的平均去除率均在 90 %以上 ,而且MBR工艺对进水有机负荷的冲击具有较强的短时适应能力 ,当COD污泥负荷率由 0 2 7g/ (g·d)突然增加至 0 5 4 g/ (g·d)时 ,出水COD浓度未出现明显的波动 .通过GC/MS分析得出 ,膜组件出水中剩余的有机物主要为高分子量的烷烃类 ,膜组件对于保证系统的最终出水水质起到了关键的作用 .当反应器中的污泥处于增长期时 ,在生物同化作用与同步硝化 反硝化共同作用下 ,使得TN具有 4 0 %左右的去除效果 ,当污泥浓度处于稳定期时 ,TN去除率下降为 30 %左右 ,主要是同步硝化 反硝化的结果 .当污泥处于增长期时 ,通过生物同化作用对TP具有一定的去除效果 ,而当污泥浓度稳定后 ,对TP基本没有去除效果 。