铁氧体法处理含铬废水及铬回收实验研究

通过实验研究了铁氧体法处理含Cr6+废水和回收铬的工艺条件,包括Fe2+/Cr2O27-(摩尔比)、反应pH值、温度、酸化pH值。得出实验的最佳工艺条件为:酸化pH为3.0、Fe2+/Cr2O27-(摩尔比)为12∶1、反应pH值为9、温度为70℃。在此工艺条件下,处理后废水中Cr6+的浓度可达到国家环保排放标准(GB8978-1996),且回收率相对较高,最高可达67.21%。     

重组人骨形态发生蛋白-7工程菌的高密度发酵

目的建立重组人骨形态发生蛋白-7(rhBMP-7)工程菌的高密度发酵工艺。方法采用摇瓶及发酵罐培养工程菌BL21/pBV221-rhBMP-7,观察不同培养基、乙酸浓度、pH值、诱导时间等对工程菌菌体生长及目的蛋白表达的影响。在优化的发酵条件下培养工程菌,当菌体A600值达100时,42℃升温诱导,并对表达产物进行纯化。结果发酵培养基与LB培养基培养的工程菌目的蛋白的表达量无明显差异;乙酸可明显抑制菌体生长及目的蛋白表达;最适于菌体生长和目的蛋白表达的pH值分别为6.8和7.6;最佳诱导时间为3h。以优化的发酵条件培养的工程菌诱导3h后,目的蛋白的表达量可达菌体总蛋白的34.9%,最终菌体A600值可达139.5;经纯化的目的蛋白纯度可达95%以上。结论已初步建立了rhBMP-7工程菌的高密度发酵工艺。     

水热法制备均分散α-Fe2O3纳米粒子

系统地研究了以Fe(NO3)3为原料,水热合成α-Fe2O3纳米粒子时,前驱物pH值对产物形貌的控制作用.实验结果显示,以Fe(NO3)3为前驱物直接进行水热处理,所得产物形貌为片状;如果Fe(NO3)3溶液用氨水中和形成Fe(OH)3凝胶后,再调节不同的pH值作前驱物,经水热处理所得产物均为单晶粒子,且在不同的pH值下,粒子形貌明显不同:当pH为1时为菱形粒子;pH为3,5时粒子形貌为近球形多孔结构;pH为7时为菱形粒子;pH为9时粒子形貌为近球形、无孔结构.同时分析了在水热条件下前驱物pH值对产物粒径的影响,另外还讨论了反应体系中存在的电解质对α-Fe2O3生成速率的影响机理.     

果蔬垃圾及餐厨浆液水解酸化处理试验研究

针对果蔬垃圾、餐厨浆液水解酸化反应进行研究,考察了人工接种厌氧沼液水解酸化阶段中,水果垃圾、蔬菜垃圾、果蔬混合垃圾以及餐厨浆液在不同工况下pH值、 NH_3-N、 TN、 COD、 BOD_5和VFA等指标的变化,探究水解酸化液作为水处理反硝化外加碳源的可行性。结果表明:缺氧状态下,pH值、温度、机械搅拌转速分别控制在6.8~7.2、 37.0℃、 150 r/min,不同反应体系稳定水解酸化均在第4天达到峰值,VFA占COD比例为18.7%~23.9%, m(BOD5)/m(COD)为0.27~0.39, m(BOD5)/m(TN)为4.0~13.1,各原料均具有较好的可生化性,水果垃圾和餐厨浆液的水解酸化产物可作为优质的污水反硝化碳源。     

橡胶促进剂NS废水预处理实验研究

橡胶促进剂NS生产废水采用酸化吹脱-混凝法进行预处理,考察废水pH、吹脱时间以及混凝剂种类、投加量、助凝剂投加量和混凝pH等对COD去除率的影响。结果表明,酸化吹脱-混凝法处理该废水的最佳酸化pH值为3,吹脱时间为120 min;最佳混凝剂为PFS(聚合硫酸铁),投加量1 400 mg/L,混凝pH值为7,助凝剂PAM 14 mg/L。酸化吹脱及混凝处理后,出水COD去除率值为53.75%。     

淀粉改性高分子重金属絮凝剂的合成与性能研究

用(NH4)2Fe(SO4)2/H2O2为引发剂合成淀粉-丙烯酰胺高分子共聚物,利用CS2在碱性条件下黄原酸化,合成高分子重金属絮凝剂(SAX).研究絮凝剂去除水中的Pb2+的反应条件及机理.实验结果表明,溶液的pH值对pb2+的去除效果有较大影响,pH值高时去除效果好,去除率可达99.70%,而且絮凝剂还具有较好去除...     

甜菜碱类酸化自转向剂的性能评价

自转向酸对于非均质储层酸化效果较好,通过室内实验对芥酸酰胺丙基甜菜碱表面活性剂用作酸化自转向剂进行了性能评价。结果表明,甜菜碱自转向剂体系黏度随着pH升高先增大后稳定,Ca⁽²⁺⁾能够显著增加残酸黏度。当pH值为4时,5%甜菜碱JAB浓度的酸液黏度最大值可达414 mPa·s。体系具有较好的耐温性和抗剪切性,在90℃时170 s(2+)能够显著增加残酸黏度。当pH值为4时,5%甜菜碱JAB浓度的酸液黏度最大值可达414 mPa·s。体系具有较好的耐温性和抗剪切性,在90℃时170 s^(-1)下黏度仍可达220 mPa·s,且破胶性能好,破胶后黏度<5 mPa·s,易返排,对储层伤害小。双岩心并联流动实验表明,甜菜碱自转向酸化效果明显,对低渗透岩心的渗透率改善率可达78.2%,可满足非均质碳酸盐岩储层的酸化转向需要。     

EGSB处理高浓度有机废水的启动与微生物相

以葡萄糖配制水样为处理对象,研究了接种颗粒污泥的EGSB(厌氧颗粒污泥膨胀床)反应器处理高浓度有机废水的运行规律。经过大约5个月的运行,结果表明:中温条件(30±1)℃下,当进水COD的质量浓度为8000～12000mg/L时,进水COD容积负荷可达42.3kg[COD]/(m3·d),COD去除率可达85%;当COD容积负荷小于9.8kg[COD]/(m3·d)时,进水pH值对于EGSB没有大的影响;超过此值时,应添加碱调节进水的pH值,以避免反应器的酸化;有机容积负荷小于14.3kg[COD]/(m3·d)时,甲烷短杆菌占优势,高于此值时,甲烷八叠球菌占优势。     

高水灰比条件下pH值对硫铝酸盐水泥水化的影响

研究了高水灰比(1.0)与常规水灰比(0.5)条件下pH值对硫铝酸盐水泥凝结时间和抗压强度的影响,并对其水化产物,孔结构和微观形貌进行了分析.结果 表明:pH值大于13时硫铝酸盐水泥凝结时间大幅缩短;pH值提升到13.5时硫铝酸盐水泥超高水灰比条件下抗压强度大幅提升.高pH值条件下钙矾石产物长径比增大,微观结构更加致密,硬化浆体的总孔隙率和最可几孔径减小.     

Fenton试剂-混凝沉淀深度处理煤气化废水的实验研究

介绍了Fenton试剂-混凝沉淀深度处理煤气化废水的实验,讨论了H2O2投加量、FeSO4投加量、反应pH值及反应时间对CODCr去除率的影响。实验所得最佳条件为:H2O2投加量600mg/L、FeSO4投加量200mg/L,酸化槽内pH值控制为3±0.5,水力停留时间30min;中和释气槽内pH值控制7±1,水力停留时间30min;沉淀器进水加入PAM 5mg/L,水力停留时间90min。在此条件下,最终CODCr去除率可达71.7%,色度去除率达到79.89%。     

pH主导不同反应器处理含砷酸性废水性能比较

分别采用外循环上流式厌氧污泥床(UASB)和厌氧续批式(ASBR)反应器处理模拟含砷酸性废水,考察2种厌氧反应器对模拟含砷酸性废水的处理效果及运行特性。结果表明,外循环UASB较ASBR能更好地应用于模拟废水的处理,外循环UASB和ASBR对COD、SO_4~(2-)和As(Ⅲ)的去除率分别达到74.3%、88.7%、63%和42.8%、73.2%、35%。反应体系对模拟废水的处理效果受pH主导:反应体系pH影响SRB的生长、代谢,进而影响对COD和SO42-的去除效果;As(Ⅲ)主要通过与SRB代谢产物(H_2S/S~(2-))的沉淀作用被去除,pH对AsxSy的溶解度影响较大,进而影响As(Ⅲ)的去除效率。     

Stability enhancement of anaerobic digestion through membrane gas extraction under organic shock loads

A novel submerged silicone membrane extraction technique for removing the dissolved gases, CO₂ and H₂, was explored as a method for enhancing the stability of anaerobic digesters under shock loads. The effectiveness of this strategy was demonstrated during a five-fold step increase in the feed concentration from 4 kg m⁻³ to 20 kg m⁻³ Chemical Oxygen Demand (COD) to two anaerobic chemostats, a control and a membrane reactor, operating under steady state. Data revealed that membrane extraction of CO₂ enabled neutral pH values to be maintained during the shock, in contrast to the control; and this appeared to enhance acetate degradation. In addition, while liquid phase hydrogen removal was only partially successful due to a biofilm building up on the membrane, it also appeared to enhance the rate of volatile fatty acid degradation, and hence improved reactor stability. Floc sizes were monitored during the course of the shock load experiment and found to decrease from 46 μm to 30 μm over 35 days in the control, but from 37 μm to <5 μm in the membrane reactor. This decrease in floc size was postulated to be due to the growth of a relatively pure methanogenic biofilm on the membrane. © 1998 Society of Chemical Industry     

Influence of Reactor Configuration on the Selective Oxidation of Glycerol over Au/TiO2

The oxidation of glycerol by molecular oxygen in the aqueous phase over Au/TiO₂ was investigated in both a batch reactor and a continuous upflow fixed bed reactor. The effects of catalyst particle size, gas flow rate, liquid flow rate, reaction temperature, dioxygen pressure, and solution pH were examined in the fixed bed system. The unique hydrodynamics of the fixed bed system allowed for secondary oxidation products such as tartronic acid and oxalic acid to form in substantial amounts, which contrasts the product distribution observed in a batch system. These results suggest that reactor configuration can play an important role in the observed product selectivity from oxidation reactions over highly active gold catalysts.     

上流式厌氧污泥床反应器处理凉果废水性能研究

采用上流式厌氧污泥床反应器(UASB)法处理凉果废水,考察废水厌氧处理过程中COD、浊度、脱色率、pH、电导率、悬浮物去除率的变化规律。结果表明:随着厌氧时间的增加,UASB反应器对废水的处理效果不断提高。在最适宜的厌氧时间条件下,废水的COD去除率达62.0%、浊度去除率达41.1%、吸光度及脱色率分别为0.498及48.4%、pH为5.4、悬浮物去除率达30.3%。故,UASB法可作为凉果废水的预处理方式,以降低后续废水的好氧处理难度。     

厌氧与光合微生物联合制氢工艺实验研究

利用厌氧细菌暗发酵产氢和光合细菌光发酵产氢的优势和互补协同作用而联合起来的两步法制氢,探讨不同底物浓度对厌氧发酵阶段产氢的影响、厌氧发酵时间对产氢发酵过程的影响;光合微生物发酵随发酵时间的产氢情况。结果表明,葡萄糖浓度对厌氧生物产氢有很大的影响, 15 g/L 的葡萄糖浓度有较好的产氢量。葡萄糖利用率和挥发性脂肪酸的总量随厌氧发酵时间的变化情况表明,在厌氧发酵阶段,以葡萄糖为底物,最佳的葡萄糖浓度为 15 g/L。在 37 h 的葡萄糖利用率达到 72.08%,挥发性脂肪酸总量达到 9 326.3 mg/L,每克葡萄糖累计产氢量为 182 mL。在厌氧发酵时间 37 h 时把厌氧发酵的产物移到光合发酵反应器,接种位于生长对数期的光合细菌群,调节培养液的pH值和加入光源进行光合产氢,88 h 时每克葡萄糖累计产氢达到 352 mL,两步联合制氢每克葡萄糖累计产氢量共可达到 534 mL。     

Effect of changes of pH on the anaerobic/aerobic transformations of biological phosphorus removal in wastewater fed with a mixture of propionic and acetic acids

Most studies on the transformation of enhanced biological phosphorus removal have used acetic acid as the carbon source and focused on the anaerobic phase. In this paper the anaerobic and aerobic transformations of phosphorus removal microorganisms at various pH values were investigated with wastewater containing 3.14 mM C propionic acid and 1.56 mM C acetic acid. It was observed that the influence of acidic pH on the concentrations of mixed‐liquor suspended solids and biomass was stronger than that of basic pH, and the maximal cell growth appeared at pH 7.6. The observed uptake rate of propionic acid was much faster than that of acetic acid at all pH values investigated, and both were affected by pH. The anaerobic transformations of polyhydroxyalkanoates and glycogen linearly decreased with increasing pH from 6.6 to 8.6, and a greater glycogen transformation correlated to greater polyhydroxyalkanoate transformation in both anaerobic and aerobic stages. Further studies revealed that at pH 6.6 and 8.6 the overall phosphorus release and uptake was low and there was no net phosphorus removal, although the initial phosphorus release was high. However, when the pH was controlled at pH 7.1 and 7.6, a phosphorus removal efficiency of 97.03% and 96.43% was achieved, respectively, which was greater than that of 87.46% at uncontrolled pH. Copyright © 2006 Society of Chemical Industry     

Anaerobic acidogenesis of dairy wastewater: the effects of variations in hydraulic retention time with no pH control

The performance of a laboratory‐scale mesophilic acidogenic reactor was evaluated in this study, in terms of volatile fatty acid production and distribution, with respect to variations in hydraulic retention time (HRT). The continuous flow‐completely mixed anaerobic reactor, coupled with a conventional gravity settling tank and a continuous recycling system, was operated in a hydraulic retention time ranging between 24 and 12 h, and up to an organic loading rate of about 9.3 kg COD m^?3 d^?1, without pH control. The acid production gradually increased proportionally to the organic loading rate, with decrease in hydraulic retention time. The highest degree of acidification and the rate of acid production were 56% and 3.1 g dm^?3 d^?1 at 12 h of HRT. Variations in hydraulic retention time affected volatile fatty acid production and distribution substantially, for the range investigated. Acetic, propionic, butyric and valeric acids were commonly produced during acidogenesis of dairy wastewater. Copyright © 2004 Society of Chemical Industry     

ABR作为产甲烷反应器的两相厌氧工艺的启动特性

用厌氧折流板反应器(ABR)作为两相厌氧工艺的产甲烷反应器进行了启动研究,寻求快速启动的办法。采取先快速提高进水COD浓度,后提高进水量的方式,使产酸相尽快维持在酸性最佳条件下,调节产甲烷相进水pH值在6.8～7.2之间,从而保证产甲烷相在最佳条件下,经过35 d的启动过程,分别在产酸反应器和产甲烷反应器中出现了性能良好的絮状活性污泥和厌氧颗粒污泥。启动后第35天,当两相反应器水力停留时间为14 h,COD负荷为36.48 kg/(m3.d)时,系统整体COD去除率达到98.0%。     

厌氧折流板反应器处理退浆废水的启动研究

对采用厌氧折流板反应器(ABR)处理难降解退浆废水的启动过程进行了研究.实验结果表明:经过90 d的运行,反应器在32～34℃、上流速度8 m/h、水力停留时间6 d、COD容积负荷1.80 kg/(m3·d)的条件下,COD去除率达到55%以上,启动成功.出水COD稳定在4 500 mg/L左右,碱度约为700～850 mg/L.运行情况表明,启动初期反应器各隔室的pH变化较大,有效控制pH是系统启动成功的关键.启动后期,各隔室pH稳定在6.8～7.3之间,挥发性脂肪酸(VFA)质量浓度为300～500mg/L.随着隔室的横向推移,污泥的SS、VSS和SS/VSS不断增大,推测反应器中厌氧微生物相分离现象显著.     

自养厌氧硫酸盐还原/氨氧化反应器启动特性

引言化工、味精、制药等工业生产过程中排放出大量含有NH+4、SO2-4废水。如何高效稳定地处理这类废水,已对废水处理技术提出了极大挑战[1]。生物处理一直被认为是废水处理领域最为经济有效的处理方式。对同时含有NH+4和SO2-4的废水,