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.     

利用氢基质生物膜反应器去除水中砷酸盐

利用氢基质生物膜反应器(Hydrogen-based membrane biofilm reactor,MBfR)研究了NO_3~--N负荷、SO_4~(2-)负荷、As(Ⅴ)负荷、氢分压对水中砷去除效果的影响.结果表明,随着NO_3~--N进水负荷的增加,As(Ⅴ)和SO_4~(2-)还原受到明显抑制,系统产生As(Ⅲ)和NO_2~-的积累;随着SO_4~(2-)进水负荷的增加,反应器内总砷去除率由78.6%(25 mg·L-1SO_4~(2-))降低至1.1%(200 mg·L~(-1)SO_4~(2-)),而此时NO_3~--N的去除基本不受影响.同时,随着进水As(Ⅴ)负荷从0.25 mg·L~(-1)增至2 mg·L~(-1),出水SO_4~(2-)浓度明显升高,反应器内总砷去除率从70.0%降低至47.3%,而此时NO_3~--N的去除基本不受影响;当氢分压低于0.06 MPa时,提高氢分压可降低出水As(Ⅴ)浓度,当氢分压高于0.06 MPa后便不再是控制因素.由于体系中氢自养还原微生物会优先利用NO_3~--N和SO_4~(2-)作为电子受体,因此,为了保证As(Ⅴ)的高效还原去除,必须控制氢分压在0.05~0.07 MPa之间.     

Performances of biological aerated filter employing hollow fiber membrane segments of surface-improved poly （sulfone） as biofilm carriers

Using the surface of poly （sulfone） hollow fiber membrane segments as grafted layer, the hydrophilic acrylamide chain was grafted on by UV-photoinduced grafting polymerization. The gained improvement of surface wettability for the modified membrane was tested by measuring the contact-angle as well as FTIR spectra. Then correlation between the hydrophilic ability of support material and the biofilm adherence ability was demonstrated by comparing the pollutant removal rates from urban wastewater via two identical lab-scale up-flow biological aerated filters, one employed the surface wettability modified poly （sulfone） hollow fiber membrane segment as biofilm carder and the other employed unmodified membrane segment as biofilm carder. The experimental results showed that under the conditions of influent flux 5 L/h, hydraulic retention time 9 h and gas to liquid ratio （G/L） 10： 1, the removal rates of chemical oxygen demand （COD） and ammonium nitrogen （NH4^＋-N） for the modified packing filter and the unmodified packing filter was averaged at 83.64% and 96.25%, respectively, with the former filter being 5%-20% more than the latter. The effluent concentration of COD, NH4^＋-N and turbidity for the modified packing filter was 25.25 mg/L, 2 mg/L and 8 NTU, respectively. Moreover, the ammonium nitrogen removal performance of the filter packing the modified PSF was compared with the other bioreactor packing of an efficient floating medium. The biomass test indicated that the modified membrane matrixes provided better specific adhesion （3310-5653 mg TSS/L support）, which gave a mean of 1000 mg TSS/L more than the unmodified membrane did. In addition, the phenomenon of simultaneous denitrification on the inner surface of the support and nitrification on the outer surface was found in this work.     

螺旋对称流厌氧膜生物反应器的运行及优化

通过对螺旋对称流厌氧反应器(SSSAB)外置平板膜组件形成了螺旋对称流厌氧膜生物反应器(SSS-AnMBR).研究了SSS-AnMBR的启动阶段和有无沼气曝气时的运行性能,并建立了其设计与操作优化模型.在启动过程中,反应器内挥发性脂肪酸与碱度的比值为0.001~0.016,未发生酸化现象,后期反应器对化学需氧量(COD)的去除率稳定在90.27%~95.35%.有沼气曝气状态下SSS-An MBR的有机负荷和COD去除率分别为2.28 kg·m~(-3)·d~(-1)和98.24%,均高于无沼气曝气状态下的2.13 kg·m~(-3)·d~(-1)和97.58%,表明系统的污染物去除效能较好.有沼气曝气状态下膜组件的平均负荷、平均COD去除率和SSS-An MBR平均总COD去除率的CV值分别为21.98%、14.15%和0.78%,均低于无沼气曝气状态下的25.27%、21.98%和0.89%,表明该状态下系统稳定性较好.最后建立了厌氧反应器体积(V)、进水流量(Q)和进水COD(X)三者之间的数学模型:V/Q=HRT0/C_(inf)×η_(sss)(X-Cinf)+HRT_0,以及膜面积A与Q之间的数学模型:A=Q×C_(sss)×η_m/MLR,可指导同类型的厌氧膜生物反应器的设计和操作优化.     

Removal of nitric oxide from simulated flue gas via denitrification in a hollow-fiber membrane bioreactor

A hollow-fiber membrane bioreactor(HMBR) was studied for its ability to treat nitric oxide(NO) from simulated flue gas. The HMBR was operated for 9 months and showed a maximum elimination capacity of 702 mg NO/(m2·day) with a removal efciency of 86%(gas residence time of 30 sec, inlet NO concentration of 2680 mg/m3, pH 8). Varying operation parameters were tested to determine the stability and response of the HMBR. Both the inlet NO concentration and gas residence time influenced the removal of NO in the HMBR. NO elimination capacity increased with an increase in inlet NO concentration or a shortening of gas residence time. Higher removal efciency of NO was obtained at a longer gas residence time or a lower inlet NO concentration. Microbial communities of the HMBR were sensitive to the variation in pH value and alkalescence corresponding to an optimum pH value of 8. In addition, NO elimination capacity and removal efciency were inversely proportional to the inlet oxygen concentration. Sulfur dioxide had no great influence on elimination capacity and removal efciency of NO. Product analysis was performed to study N2O and N2 production and confirmed that the majority of the microorganisms were denitrifying bacteria in the HMBR. Compared to other bioreactors treating NO, this study showed that the denitrifying HMBR was a good option for the removal of NO.     

Membrane flux dynamics in the submerged ultrafiltration hybrid treatment process during particle and natural organic matter removal

Exponential relationship was developed to quantify the normalized membrane flux dynamics during the filtration period and fitted the results well.     

我国餐饮废水处理方法的研究进展

综述了我国餐饮废水的处理方法，具体分析和比较了生物降解、膜生物反应技术、混凝法和电化学法的优缺点。指出组合物理、化学和生物法，将是解决我国餐饮废水污染问题的最佳途径，并对今后我国餐饮废水处理技术研究方向进行了展望。     

Preparation and characterization of PVDF-glass fiber composite membrane reinforced by interfacial UV-grafting copolymerization

A novel inorganic–organic composite membrane,namely poly(vinylidene fluoride) PVDF-glass fiber(PGF) composite membrane,was prepared and reinforced by interfacial ultraviolet(UV)-grafting copolymerization to improve the interfacial bonding strength between the membrane layer and the glass fiber.The interfacial polymerization between inorganic–organic interfaces is a chemical cross-linking reaction that depends on the functionalized glass fiber with silane coupling(KH570) as the initiator and the polymer solution with acrylamide monomer(AM) as the grafting block.The Fourier transform infrared spectrometer-attenuated total reflectance(FTIR-ATR) spectra and the energy dispersive X-ray(EDX) pictures of the interface between the glass fiber and polymer matrix confirmed that the AM was grafted to the surface of the glass fiber fabric and that the grafting polymer was successfully embedded in the membrane matrix.The formation mechanisms,permeation,and anti-fouling performance of the PGF composite membrane were measured with different amounts of AM in the doping solutions.The results showed that the grafting composite membrane improved the interfacial bonding strength and permeability,and the peeling strength was improved by 32.6% for PGF composite membranes with an AM concentration at 2 wt.%.     

聚醚砜纳滤膜的制备及改性研究进展

聚醚砜是一种性能优异的纳滤膜材料,具有耐热、耐压、耐燃、耐辐射、抗酸、抗氧化、抗溶剂、生物相容性好等优点,应用前景十分广阔。文章重点介绍了相转化法、共混法、荷电法、复合法等聚醚砜纳滤膜制备方法,以及表面涂覆、材料共混等物理改性方法和膜材料本体改性、膜表面接枝改性等化学改性方法,阐述研究现状,并予以评价,同时提出探索新的制膜及改性方法,降低膜成本,提高制膜过程中的环境友好性,是聚醚砜纳滤膜制备及改性的重要发展方向。     

微藻对海水养殖循环水高效碳氮磷一体化去除的研究

海水养殖循环水高盐分和波动的低碳氮比造成水处理困难和亚硝酸盐累积,影响循环水处理利用,其排放造成受纳海域生态环境破坏.本研究采用混合营养型钝顶螺旋藻结合膜光合反应器（MPBR）考察碳氮比对海水养殖循环水碳、氮、磷一体化去除效率及藻生物质产量的影响.结果表明,在原水碳氮比为5时,钝顶螺旋藻可实现碳、氮、磷高效一体化去除,出水COD低于20 mg·L^-1,满足《海水养殖水排放要求》（SC/T 9103—2007）一级标准,总氮和总磷浓度均满足二级标准.提高碳氮比有利于钝顶螺旋藻的生长、油脂累积和氮磷的去除,碳氮比为1~10时藻体内油脂含量由14.9%增到19.3%.钝顶螺旋藻膜光合反应器（MPBR）运行数据表明,聚偏二氟乙烯（PVDF）膜和无纺布生物膜均可高效稳定地截留微藻,稳定运行期出水COD、总氮和总磷浓度均满足《海水养殖水排放要求》（SC/T 9103—2007）二级标准,且均无亚硝酸盐累积.无纺布生物膜光合反应器COD去除效率（93.2%）和藻体的多糖含量（98.1 mg·g^-1）显著高于PVDF膜反应器（85.2%和70.4 mg·g^-1）,膜通量也较低,膜污染较轻.本研究中钝顶螺旋藻结合无纺布动态生物MPBR不仅实现了海水养殖循环水高效的碳、氮、磷同步去除,无亚硝酸盐累积,并可稳定收获生物质资源,为海水养殖循环水高效、安全处理和资源化利用提供依据.