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...

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.

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.

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.

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.

SMBR工艺处理废水时操作方式的研究

膜生物反应器(MBR)在废水处理中必须能保证长期稳定运行,而操作方式与MBR运行性能密切相关。通过对小试规模的浸没式MBR(SMBR)恒流和恒压两种操作方式的短期以及长期实际运行研究,发现次临界区恒流操作和经济操作压力TMP以下的恒压操作有利于MBR的长期稳定运行;并从理论上分析了对应于不同的操作区域的膜污染机理。

优化曝气方式对减缓SMBR一体式反应器中膜污染的影响

在相同运行条件下,研究了改进型曝气方式(膜出水时气水比为20:1,停止抽吸时气水比为40:1)和传统曝气方式(采用气水比40:1连续曝气)一体式膜生物反应器下SMBR的运行情况。试验结果表明:改进曝气方式的SMBR中胞外聚合物(EPS)和溶解性微生物产物(SMP)浓度以及料液粘度都低于传统的SMBR,减轻了膜污染,直观表现为具有较低的跨膜压力(TMP);两种曝气方式的膜阻力均以沉积层阻力为主,改进曝气方式的SMBR沉积层阻力所占比例高于传统的SMBR,后者膜孔吸附及堵塞阻力所占比例远高于前者,因此后者膜清洗费用高;此外改进型曝气方式由于其阶梯式曝气强度降低了能耗。

内电解-SMBR组合工艺处理蒽醌活性染料废水

采用自制的PVDF中空纤维膜组件构建浸入式膜生物反应器,进行了内电解-SMBR组合工艺处理难降解蒽醌染料(活性艳蓝X-BR)废水的试验.试验分为2组,一组为内电解出水直接进入的SMBR-3,另外一组为内电解出水经调节pH值达9～10后进入的SMBR-4.结果表明,组合工艺中2组SMBR对CODCr、色度和NH4+-N的去除率均很高,且相差不大;但两反应器对TN的去除效果却有明显差异,由于良好生物铁絮体的存在,SMBR-3对TN的去除可高达92.8%,而SMBR-4对TN的去除只有67.5%.与pH值调节后进水相比,内电解直接进水导致活性污泥絮体粒径增大34μm,EPS总量明显增加,且微生物表面结构中有丝状菌出现,菌种也变得相对复杂.对SMBR膜材料进一步检测发现,内电解直接进水所形成的生物铁絮体还可有效减轻膜污染,使膜通量衰减变慢.

曝气强度对SMBR膜污染的影响

改变曝气强度是控制SMBR(Submerged Membrane Bioreactor)膜污染的重要手段之一.在不同的曝气强度下考察了膜过滤压差随时间的变化情况,膜阻力构成情况和污泥指数SVI(Sludge Volume Index)的变化对膜污染的影响.结果表明:曝气强度过大或过小,压差上升速率都会增大;随着曝气强度的增大,Rp,Ref,Rc在过滤总阻力中所占的比例都会逐渐减小,Rif在过滤总阻力中所占的比例逐渐增大;当曝气强度低于0.88 m3.m-2.h-1时,水力剪切力主要作用于膜污染的消除,而对活性污泥的性质没有多大影响,SVI变化不大,因此压差上升速率随曝气强度的增加而降低;而当曝气强度高于0.88 m3.m-2.h-1时,水力剪切力过大,导致污泥絮体结构被破坏,SVI明显增大,从而加速了膜的污染,使压差上升速率随曝气强度的增加而增加.

低温下SRT对SMBR脱氮效果的影响研究

利用一体式膜生物反应器(SMBR),考察低温下SRT对SMBR系统脱氮效果的影响.控制DO为0.5 mg/L,pH值为6.5～7.5,HRT为2 h,MLSS为7 000～8 000 mg/L的条件下,取温度为16℃和12℃作对比.结果表明,SRT为30 d时,SMBR内取得了理想的SND效果,温度为16℃时,TN和NH3—N的平均去除率分别为93.63%和95.66%.温度为12℃时,TN和NH3—N的平均去除率分别为92.5%和94.3%.控制较好的运行条件,低温条件下系统的脱氮效果与中温时相差不大,均保持在90%以上,出水质量浓度较低.在两种温度条件下,随着SRT的延长,系统的脱氮效果均变差,去除率下降,表明实际工程中,SRT并不是越长越好.

投加氢氧化铁对SMBR中活性污泥性能的影响

试验研究了在SMBR中投加不同量氢氧化铁对出水水质以及膜污染的影响。结果表明,生物铁-SMBR中随氢氧化铁投加量的增加,COD出水及去除率略有提高;氢氧化铁投加量为5%时,对活性污泥的活性促进作用最强;活性污泥SVI的降低主要是氢氧化铁絮体本身的化学絮凝作用所致;试验条件下氢氧化铁最佳投加量为混合液污泥浓度的5%时,半透膜压增长最慢,膜污染程度最轻。

污泥膨胀对SMBR系统脱氮性能影响的试验研究

以一体式膜生物反应器(SMBR)处理模拟污水,考察了污泥膨胀对SMBR脱氮性能的影响。结果表明,在SMBR运行中,污泥膨胀期对TN和NH3-N的去除效果明显优于对照试验期,丝状菌对氮的竞争能力较强,对污水中营养物质的利用速率较高,污泥膨胀期SMBR的出水水质较好;在污泥膨胀期,随着运行时间的延长,由于丝状菌的反硝化能力较差,导致出水中出现NO2--N的少量积累;丝状菌带来的负面影响即膜污染问题较为严重,在实际的工程中应采取有效措施控制污泥膨胀。

SMBR不同特性膜处理城市内河道水对比试验研究

用一体浸没式膜生物反应器(SMBR)不同特性膜处理上海市城市内河道水,结果表明,SMBR对氨氮含量较高的富营养化河水,氨氮的去除率在90%以上,但对COD的平均去除率仅为50%.比较两种膜的运行性能,亲水性膜在运行通量和通量恢复能力上,均比疏水性膜优越.两种膜的出水水质几乎没有差异.

SMBR法处理生活污水的调试与运行

结合SMBR法处理生活污水的启动调试过程,介绍了SMBR系统启动调试的控制方法和运行经验,描述了启动过程中污泥的生长过程及工艺的运行特性,确定了启动实际工程的适宜污泥浓度,并对长期运行过程中的膜污染进行管理,结果表明:启动实际工程的适宜的污泥浓度为0.25g/L,出水水质优于国家中水标准(GB/T18920-2002),在线化学清洗和排泥对膜污染控制有良好的效果。

投加悬浮填料对SMBR工艺的影响研究

通过试验考察了向SMBR中投加悬浮填料对系统除污效果、膜污染进程和混合液污泥浓度的影响。结果表明:投加悬浮填料可明显改善系统对COD的去除效果、延缓膜污染进程。在HSMBR中的溶解氧浓度为4～5mg/L、HRT为4h的条件下,当填料填充率分别为45%、20%和0时,系统对COD的去除率分别为75%、62%和56%;对NH3-N的去除率>90%;膜清洗周期分别为40、36和24d。投加悬浮填料可明显降低反应器内的混合液污泥浓度,减少污泥产量。

电控反冲SMBR处理中药废水试验研究

采用简单的水解酸化预处理与自行研发的好氧电控反冲SMBR相结合的工艺,进行了处理富含甙类物质的中药废水的试验研究.结果表明,当进水COD为1 090.1 mg/L,反冲时间为5m in,平均HRT为5.97h时,工艺系统COD平均去除率为89.4%,出水COD浓度达GB8978-1996《污水综合排放标准》医药原料药工业污水二级排放标准,证明该工艺用于处理中等浓度的中药废水是可行的.

UASCB-SMBR处理垃圾渗滤液的试验研究

研究了厌氧污泥复合床 (UASCB) 序批式膜生物反应器 (SMBR)串联工艺 ,处理垃圾渗滤液的工艺性能及影响因素 ,并与单纯的SMBR工艺进行了对比。试验结果表明 ,在进液COD浓度平均为 2 50 0mg/L ,NH+ 4-N平均浓度为 360mg/L ,厌氧反应器COD的负荷为 7～2 0kgCOD/m3·d ,SMBR负荷为 1～ 5kgCOD/m3·d,系统总水力停留时间为 1 4～ 2 8h时 ,该串联工艺COD去除率达到 92 %以上 ,NH+ 4-N的去除率在 80

曝气强度及间歇方式对SMBR膜阻力变化特征的影响

实验采用浸没式膜生物反应器(SMBR)对某石化废水进行处理,研究了曝气强度和间歇方式对SMBR膜阻力变化特征的影响。结果表明,在曝气强度分别为7.5、15、30 m3/(m3·h)时,跨膜压差(TMP)达到TMPmax(12 k Pa)的时间分别为12.17、15.67、29.33 h;TMP变化速率K分别由2.55、2.45、2.13 Pa/s上升到5.47、5.06、3.87 Pa/s;不可逆污染的阻力分别为41.0×109、52.4×109、100×109 m-1。采用3种不同运行方式(运行-间歇9 min-1 min、8 min-2 min、7min-3 min)时,达到TMPmax的时间分别为11.67、24.67、29.33 h,K分别由0.79、2.55、2.14 Pa/s上升到2.12、3.14、3.87Pa/s,总处理水量分别为17.33、33.66、33.87 L。因此,曝气强度增加在一定程度上会缓解膜污染速率,但会引起膜阻力构成特征的变化。延长间歇时间可以缓解膜污染速率并提升系统的总处理水量,但是间歇时间过长,对总处理水量的提升有限。