A~2O-BAF联合工艺处理低碳氮比生活污水

研究了A2O-BAF联合工艺处理低碳氮比生活污水时,A2O工艺段厌氧区、缺氧区和好氧区的最佳容积比及硝化液回流比,探讨了强化该工艺的反硝化除磷工艺条件.结果表明,在A2O水力停留时间为5.6 h、污泥龄为9d、污泥回流比100%、硝化液回流比200%、BAF HRT为30 min、出水溶解氧质量浓度为6～8 mg/L的工况下处理碳氮比为3.21的生活污水,系统存在反硝化除磷现象.调节A2O工艺段各区容积比,当比值为3∶4∶2时,系统的脱氮除磷效率最佳,总氮和总磷的去除率分别是67.4%和98.6%.结果表明,维持该容积比不变,改变硝化液回流比,硝化液回流比为250%时系统反硝化除磷效果最好,其中绝大多数的聚磷菌具有反硝化除磷的能力,缺氧区出水硝态氮和总磷的质量浓度几乎为0.该双污泥工艺能充分发挥活性污泥工艺与生物膜工艺的优势,尤其对于处理低碳氮比生活污水能达到良好的处理效果.     

复合式UCT-MBR脱氮除磷效果的试验

目的 考察复合式UCT-MBR对生活污水的脱氮除磷效果.方法 针对生活污水特点,采用除磷能力较强的UCT(the University of Cape Town process)与膜生物反应器(Membrane Bioreactor,MBR)相结合的工艺,在反应器内投加立体弹性填料,构成复合式UCT-MBR,形成悬浮污泥与附着污泥共存的复杂生物相体系.结果 在HRT=8～12 h,SRT=30 d,膜出水量为10 L/h,气水比为40∶ 1条件下,经过42 d的污泥驯化,挂膜成功,其后60 d的稳定运行中,对CODCr、NH3-N平均去除率分别达到95.7%、97.7%,出水ρ(NH3-N)<2.4 mg/L.回流比为300%和400%时,TN去除效率分别为78.9%、84.1%,出水ρ(TN)<15 mg/L,并且由于生物膜的作用在好氧区发生了同步硝化反硝化.当硝化液回流比为300%时,TP的去除效果最佳,为83.2%,出水ρ(TP)<1 mg/L,满足一级B标准.结论 采用该工艺处理生活污水运行稳定,具有较强的抗冲击负荷能力,出水水质良好,达到了国家生活杂用水的要求.     

分段进水工艺水力停留时间的优化与运行策略

本研究采用改良A/O四点分段进水工艺处理低浓度、低碳氮比市政废水。在进水流量分配比为20%∶35%∶35%∶10%、缺氧/好氧体积比为1∶1、SRT为15d、污泥回流比为75%条件下,通过调整不同的水力停留时间(HRT),研究HRT对污染物去除性能的影响以及确保出水污染物达标的最短HRT与运行策略。结果表明:HRT从8.7h降低至6h,对COD、TP的去除基本无影响,但出水氨氮、TN浓度随之升高,并且进水碳源有效利用率以及好氧段同步硝化反硝化(SND)效果随之降低。当HRT为6h时,通过控制好氧段DO为1.0～1.5mg.L-1联合在好氧段投加悬浮填料的策略,出水COD、氨氮、TN、TP浓度分别为25.92、1.98、14.5和0.47mg.L-1;悬浮填料的投加可以优化出水氨氮和好氧段SND效果,且SND比例达到22%,但对进水碳源有效利用率的提高不明显。     

A^2O工艺处理生活污水反硝化除磷研究

采用A2O工艺处理低ρ(C)/ρ(N)实际生活污水,研究其脱氮除磷性能和反硝化除磷特性.试验结果表明:处理低ρ(C)/ρ(N)实际生活污水时,在不设置预缺氧区、无外加碳源的情况下,A2O工艺的脱氮除磷能力受到严重影响,出水ρ(NO3--N)高达35 mg/L,TN平均去除率仅为47.1%;此时A2O工艺除磷能力较差,缺氧段有释磷现象的发生.当设置预缺氧区后,A2O工艺的脱氮除磷能力明显提高,TN平均去除率可达60.7%,PO43--P平均去除率为55.9%;此时系统存在反硝化除磷现象,缺氧段除磷率为31.4%～46.9%.在设置预缺氧区的基础上,通过外加碳源,提高进水ρ(C)/ρ(N),可进一步提高系统的脱氮除磷能力,TN平均去除率可达74.4%,出水ρ(PO34--P)小于0.5 mg/L,缺氧段除磷率高达66.2%～90.9%.同时研究了外加碳源情况下污泥内PHA成分、含量及糖原含量在A2O系统内的沿程变化趋势.经过驯化、富集,反硝化聚磷菌相对于全部聚磷菌的代谢活性从31.1%提高到74.7%.A2O工艺反硝化除磷能力的增强,提高了碳源的利用效率.     

阶段时间对CMICAO工艺低温运行特性的影响

研究了低温下多点交替进水阶式A2/O(CMICAO)工艺阶段运行时间对污染物去除率的影响,探讨了DO、ORP以及pH状态参数与污染物去除率之间的关系.结果表明,水温8～10℃,泥龄13 d,水力停留时间16h,污泥浓度2 680～3 560 mg/L,污泥回流比30％,阶段1至6的运行时间为3、2.5、2、3、2.5、2h时,工艺出水TN、氨氮、NO3--N和TP浓度的平均值分别为10.1、1.1、7.4和0.8 mg/L.硝化反应结束时,pH由下降转为上升,ORP上升趋于平缓,DO上升趋缓;反硝化结束时,ORP曲线明显跌落,pH由上升趋于平缓并略有下降;释磷结束后ORP曲线由下降趋于平缓.降低前好氧池DO浓度,有助于同步硝化反硝化作用的发生,从而提高脱氮效率,节省能耗.     

A~2O工艺中的反硝化除磷及其强化

为研究A2O工艺中的反硝化除磷现象及影响因素,采用52.5L的A2O反应器处理实际污水.结果表明:正常运行的A2O工艺中存在反硝化除磷现象,在系统HRT为8h,污泥回流比为70%和内回流比为250%的情况下,A2O系统中缺氧区吸磷占总吸磷量的36%左右,序批试验表明,此时反硝化除磷菌占总除磷菌的35.4%.原水的C/N比越低,反硝化除磷的比例越高,但是过低的C/N比会导致TN去除率低下.将缺氧区和好氧区的容积比从1/1扩大到5/8,延长反硝化除磷反应的时间,TN去除率可从62%提高到70%左右,相比单纯提高内回流比更节能.强化A2O工艺中的反硝化除磷,为传统A2O工艺在处理低C/N比污水时提高脱氮除磷效率提供了一个新思路.     

DO对SBR短程硝化系统的短期和长期影响

采用实际的生活污水,在SBR反应器内分别考察了溶解氧(DO)对短程硝化效果及污泥种群结构的短期和长期影响.结果表明,通过采用实时控制曝气时间,高ρDO(ρ(DO)=(3±0.5)mg/L)与低ρDO(ρ(DO)=(0.5±0.1)mg/L)条件下SBR系统的亚硝酸盐积累率均能达到90%以上,而低ρDO相对于高ρDO更利于提高系统的同步硝化反硝化(SND)效果,两者的平均同步硝化反硝化率(SND率)分别为45.5%和9.5%,低ρDO下最高SND率达86%.FISH的检测结果表明,实时控制模式下反应器内亚硝酸氧化菌(NOB)逐渐被淘洗,而氨氧化细菌(AOB)变为优势硝化菌群.在高ρDO运行末期,稳定的短程污泥中AOB和NOB的相对数量分别为8%～10%和不足0.5%;在低ρDO运行末期,AOB数量出现了微弱上升,增至10%～12%,而NOB进一步被淘汰,基本检测不出.可见,采用好氧曝气时间实时控制,能对短程硝化系统内污泥种群起到优化作用,且在高、低ρDO下均能实现稳定的短程硝化效果,而低ρDO更有利于系统内亚硝酸氧化菌(NOB)的淘洗、短程硝化率的提高以及系统SND效果的加强.     

溶解氧对NBIAS系统生物除磷脱氮的影响

通过溶解氧对一池无回流间歇曝气系统( NBIAS) 对除磷脱氮效果的影响的研究表明:在NBIAS 系统运行过程中DO 和NOt- N浓度的周期性变化使系统呈现明显的厌氧—好氧—缺氧交替变化过程;DO愈大,硝化反应速度愈快,NOt- N浓度愈高,即能有效抑制在缺氧过程中的磷的释放, 保证出水水质; 当SRT在18～22 天的情况下,DO= 3 mg/l时,NBIAS处理城市污水出水TP< 1 mg/l,TP去除率> 80% 。     

复合生物反应器亚硝酸型同步硝化反硝化

以实际生活污水为对象,利用有效容积为12L的间歇式复合生物反应器(填料体积填充比为30%),通过控制ρ(DO)稳定实现了亚硝酸型同步硝化反硝化脱氮.试验结果表明,在同步硝化反硝化条件下,随着ρ(DO)的升高,亚硝化率逐渐降低,总氮去除率也呈下降趋势.曝气结束,ρ(DO)>4 mg/L时,系统的亚硝化率和总氮去除率均小于50%;当ρ(DO)为2 mg/L,温度维持在(28±1)℃,硝化过程中亚硝化率始终维持在85%以上,ρ(NH_4~+ -N)去除率大于98%,总氮去除率在75%左右.因此,在试验条件下,只要控制曝气量,使得曝气结束时反应器内ρ(DO)为2 mg/L,就可实现稳定的亚硝酸型同步硝化反硝化生物脱氮.     

碳源对低温A2O工艺反硝化除磷的影响

为丰富低温污水脱氮除磷途径并了解碳源对A2O工艺反硝化除磷的影响程度,采用单独的乙酸钠、丙酸钠及其混合物对A2O工艺处理低温污水时厌氧释磷与缺氧反硝化吸磷过程进行研究.结果表明,在水温为10～12℃、HRT为8 h、污泥回流比为50%和硝化液回流比为150%～250%的条件下,不同碳源时厌氧释磷与缺氧吸磷速率差异较大....     

Study on the separation of Co2+ from Zn2+, Cd2+ by anion-exchange chromatography

The separation of Co²⁺ from Zn²⁺, Cd²⁺ by anion-exchange chromatography was discussed. The chromatographic column containing anion resin 201 × 7 which was saturated with a solution of ammonium chloride. The effects of the eluant acidity and eluant composition on the separation were investigated. The results indicate that this anion-exchange chromatography is suitable to the separation of Co²⁺ from Zn²⁺, Cd²⁺, and the condition of separation is simple and convenient. When the column is saturated with NH₄Cl solution (2.0 mol/L, pH=4.0), the separation can be completed effectively. Zn²⁺ and Cd²⁺ can also be separated when different eluants are used and the pure solution with high concentration of Zn²⁺, Cd²⁺ respectively can be obtained easily. Biography of the first author: WANG Xin-yan, born in Dec. 1975, majoring in extraction chemistry.     

基于GA-ANN模型的A2/O工艺运行参数优化

影响A~2/O工艺运行的参数有许多,这些因素相互联系、相互作用,影响工艺效率.为了弥补控制单一变量法或者设计正交试验法的不足,综合考察多种运行参数对工艺运行效果的影响,建立了基于遗传算法进行全局寻优的神经网络模型(GA-ANN模型),并应用于某城市污水处理厂A~2/O工艺的运行优化.获得该厂调试运行期间154组有效监测数据后,随机选取2/3的数据用于GA-ANN模型的求解,1/3的数据用于模型的检验,对工艺运行参数进行优化,得到最佳运行参数组合.结果显示,建立基于遗传算法的神经网络模型用于A~2/O工艺运行参数的优化是可行的,可以为污水处理厂运行参数的设置提供理论参考,对调试工作、提高工艺运行效率具有一定的实际指导意义.     

Design of systolic BN circuits in Galois fields based on quaternary logic

The BNoperation is known as an efficient basic operation in Galois fields GF(2k),and various algorithms and implementations using binary logic signals have already been proposed.In order to reduce the circuit complexity and long latency of BNoperations,a novel algorithm and its systolic architecture are proposed based on multiple-value logic(MVL).In the very large scale integration(VLSI)realization,a kind of multiple-valued current-mode(MVCM)circuit structure is presented and in which the combination of dynamic source-coupled logic(SCL)and different-pair circuits(DPCs)is employed to improve the switching speed and reduce the power dissipation.The performance is evaluated by HSPICE simulation with 0.18μm CMOS technology.The transistor numbers and the delay are superior to corresponding binary CMOS implementation.The combination of MVCM circuits and relevant algorithms based on MVL seems to be potential solution for high performance arithmetic operationsin Galois fields GF(2k).     

Quantification of CP4-EPSPS in genetically modified Nicotiana tabacum leaves by LC-MS/MS with 18O-labeling

The CP4-EPSPS gene is widely used in herbicide-tolerant plants/crops all over the world. In this study, a method was developed by coupling liquid chromatography with high sensitivity to tandem mass spectrometry to quantify the amount of CP4-EPSPS expression in Nicotiana tabacum leaves. The quantification of protein was converted to measure the unique peptide of CP4-EPSPS protein. One peptide unique to CP4-EPSPS was synthesized and labeled with H₂ ¹⁸O to get ¹⁸O stable isotope labeled peptide. The peptide served as the internal standard. The validated method had good specificity and linearity. The intra-and inter-day precisions and accuracy for all samples were satisfactory. The results demonstrated that the novel method was sensitive and selective to quantify CP4-EPSPS in the crude extract without time-consuming pre-separation or the purification procedures.     

Design of AB2 in Galois Fields Based on Multiple-Valued Logic

A new AB~2 operation in Galois Field GF(2~4)is presented and its systolic realization based on multiple-valued logic(MVL)is proposed.The systolic structure of the operation employs multiple-valued current mode(MVCM)by using dynamic source-coupled logic(SCL)to reduce the transistor and wire counts,and the initial delay.The performance is evaluated by HSPICE simulation with 0.18μm CMOS technology.A comparison is conducted between our proposed implementation and those reported in the literature.The transistor counts,the wire counts and the initial delay in our MVL design show savings of about 23%,45%,and72%,in comparison with the corresponding binary CMOS implementation.The systolic architecture proposed is simple,regular,and modular,well suited for very large scale integration(VLSI)implementation.The combination of MVCM circuits and relevant algorithms based on MVL seems to be a potential solution for high performance arithmetic operations in GF(2~k).     

Ca2+对SiO2-BSA混合体系膜污染行为的影响

为研究Ca²⁺对SiO₂-BSA混合污染物膜污染行为的影响,针对SiO₂与牛血清蛋白(BSA)共存体系,在不同Ca²⁺浓度下,使用原子力显微镜测定各污染物与聚偏氟乙烯(PVDF)超滤膜及各污染物之间的作用力,结合膜污染实验,探讨Ca²⁺对SiO₂-BSA混合污染物膜污染行为的影响.结果表明:随着Ca²⁺浓度的增大,SiO₂-BSA引起的膜污染逐渐减小,主要是因为Ca²⁺改变了SiO₂-BSA混合体系中各污染物与膜及污染物之间的相互作用力.针对污染物与膜之间的相互作用力,Ca²⁺的加入触发了PVDF膜与BSA及SiO₂之间的水合排斥力,从而削弱BSA在膜表面的吸附累计速率,有效减缓了运行初期的膜污染速率;针对污染物之间的作用力,Ca²⁺浓度的增加使得SiO₂-SiO₂及SiO₂-BSA之间作用力增大,从而导致污染物团聚形成大尺寸聚集体,在膜面形成松散多孔的污染层,进而伴随着膜污染速率以及污染幅度的减小.     

Self-cleaning glass coated with Fe^3＋ -TiO2 thin film

The self-cleaning glass coated with Fe^3 -TiO2 photocatalytic thin film was prepared by sol-gel process from the system Ti(OC4H9),-NH(C2H4OH)2-C2H5OH-H2O containing FeCl3. The microstructure and properties of the film were studied using differential thermal analysis-thermogravimetry(DTA-TG), X-ray diffration (XRD) and scanning electron microscope(SEM). The transmittance of the self-cleaning glass was measured by using UV-Vis spectrometer. The effects of content of Fe^3 and the thickness of Fe^3 -TiO2 thin film on the photocatalytic ac-tivity were examined. The results show that the photocatalytic thin films are mainly composed of Fe3O4 and TiO2 particles within 10-100 nm. The appropriate amount of Fe^3 is effective for improving the photocatalytic activities of TiO2. The best photocatalytic activity is obtained when the molar ratio of Fe^3 to TiO2 is 0. 005 and the glass is coated with 9 layers.     

Mechanism and behaviors of Cr3+-doped TiO2

TiO₂ powder and TiO₂ thin film on the surface of glazed ceramic tile were prepared by sol-gel method. The influences of different doping Cr³⁺ concentration on the photocatalytic activity of TiO₂ were discussed, UV-visible and X-ray diffraction analysis were used to test the performance of TiO₂ powder and film. The results indicate that photocatalytic activity of doping Cr³⁺-TiO₂ thin film is higher than that of powder, and the interaction between Cr³⁺-doped and substrate can greatly enhance the photocatalytic activity. The results of X-ray diffraction and photoabsorption show that the Cr³⁺-doped energy level in TiO₂ is 0.62 eV high from the top of valence band, which belongs to the type of deep energy level doping. On the basis of the semiconductor energy level theory and Cr³⁺ dopant energy level, the semiconductor energy level model of Cr³⁺ in TiO₂ powder and thin film were established, and the doping mechanisms of Cr³⁺-doped in TiO₂ powder and thin film were analyzed. Foundation item: Project (20466001) supported by the National Natural Science Foundation of China     

冷却水中SO42-对凝汽器不锈钢管的缓蚀作用

用电化学方法进行了大量试验,认为Ｃｌ＾－对不锈钢管是侵蚀性离子,ＳＯ＾２－４对不锈钢管是缓蚀性离子,在选用不锈钢管材时要综合考虑冷却水中Ｃｌ＾－和ＳＯ＾２－４对不锈钢管的缓蚀作用。     

电厂原水氯离子的变化规律

氯离子浓度是凝汽器不锈钢管选材的重要依据.对不同地区特别是长江口水域氯离子浓度的数据进行了统计分析和影响因素研究.结果表明:长江口水域氯离子浓度近似服从对数正态分布,氯离子浓度与电导率高度正相关,可用电导率推算氯离子浓度及其变化规律.