压力曝气生物反应器固液分离系统研究

对压力曝气生物反应器中混合液固液分离设备进行了研究,实验表明:采用反应器尾气曝气脱气工艺,脱气效果比较好。设备曝气气水比为15∶1²0∶1、脱气池水力停留时间为0.520∶1、脱气池水力停留时间为0.5¹.0h、长宽高比为4∶2∶1较为适合,采用往复式廊道结构,池底设微孔曝气头。脱气后污泥沉淀性能可以达到固液分离效果。     

H-O-BAF生物组合工艺处理皮革废水

采用水解酸化-生物接触氧化-上向流生物曝气滤池(H-O-BAF)组合工艺对皮革废水进行生物处理实验.分析了皮革废水水质和可生化性.研究了溶解氧质量浓度(DO)和水力停留时间(HRT)对该工艺处理效果的影响.该工艺处理皮革废水合适的HRT为:水解酸化10 h,生物接触氧化6 h,生物曝气滤池3 h左右.在合适的操作条件下该工艺对皮革废水COD、色度和总铬的去除率分别达到72.8%、80.0%和66.6%,处理出水水质达到排放标准.     

水解酸化-生物接触氧化工艺处理中草药废水启动特性研究

为了解水解酸化-生物接触氧化工艺在处理中草药加工废水的处理效果,将参数调试为在水解酸化池水力停留时间13.5h,溶解氧浓度0.1~0.2mg/L,生物接触氧化池水力停留时间21.6h,溶解氧浓度2~3mg/L,进行反应器的启动试验。最终经过20d完成了该工艺反应器的启动,测定了反应器的COD、总氮、总磷和色度情况。结果表明,在经过反应器处理后,COD的去除率为60%以上,总氮去除率为50%以上,总磷去除率为60%以上,色度去除率为60%以上,反应器对废水各项指标的去除率非常稳定。     

气浮-曝气生物滤池工艺处理洗浴废水回用工程

采用气浮-曝气生物滤池工艺对某校学生浴室洗浴废水进行处理,并将出水回用于校园景观水体。整个处理工艺采用自动控制。改良的曝气生物滤池具有处理能力强、处理效果好、不需二沉池、流程简洁的特点。在进水CODCr、BOD5、NH3-N、TN、TP、LAS的质量浓度分别为:120～300、60～90、17～20、35～50、2.2～4.5、3～10mg/L时,出水水质分别为:30～50、5～6、3～5、5～12、0.2～0.3、0.3～0.4mg/L,能够达到《城市污水再生利用景观用水水质标准》(GB/T18921-2002)的要求。     

曝气生物法深度处理制药废水

设计利用曝气生物法处理经过两级接触氧化的制药废水,研究了曝气生物滤池的启动和水力停留时间、水力负荷及进水COD对废水中COD、NH4+-N去除率的影响。结果表明,在气水体积比为10:1,水力停留时间为12 h时,COD去除率最大;进水COD在320～780 mg/L,COD去除率随进COD的增加而增加;在进水COD为320～780 mg/L,水力停留时间12 h,水力负荷0.23 L/h,气水体积比10:1的条件下,NH4+-N的去除率稳定在45%～56%。出水达到国家生活杂用水标准。     

管式膜-生物流化床处理生活污水试验研究

采用1种新型的管式膜-生物流化床工艺进行生活污水处理试验。结果表明,当调节HRT为3 h、曝气体积流量为60 L/h时,系统能长时间稳定运行,对COD、NH4+-N和TN的去除率分别达到95%、94.2%和84.6%,具有较好的降解有机物及脱氮能力。膜的截留对有机物和氮的去除起到一定的强化作用。     

铁碳微电解-曝气膜生物反应器处理印染废水

采用铁碳微电解-曝气膜生物反应器(物化-生化)组合工艺对河北省某印染厂的工业废水进行处理。结果表明,铁碳微电解处理废水的优化运行条件,即铁碳质量比3:1、pH为5、曝气反应时间4 h,在此条件下,COD、色度的去除率分别为55%、75%。铁碳微电解处理过后的废水再经曝气膜生物反应器COD负荷为7 g/(m~2·d)、水力停留时间6 h时,处理效果为优。组合工艺对印染废水COD、色度的平均去除率分别为93.8%、91.6%,处理后出水水质满足GB 4287-2012要求。     

曝气生物滤池-臭氧氧化-曝气生物滤池组合工艺对印染废水的深度处理

采用曝气生物滤池(BAF)-臭氧氧化-曝气生物滤池三段组合工艺对二级生化后的印染废水进行深度处理,进水COD为90～150 mg/L,色度为16-32倍,经该工艺处理后的出水COD<35 mg/L,去除率>75%,色度降到4倍以下.工程运行实践表明,该深度处理系统运行稳定,处理效率高,出水水质达到印染场洗水工序对水质的要求.     

初沉池-曝气生物滤池工艺处理城市河道污水性能研究

采用初沉池-曝气生物滤池工艺处理城市河道污水,主要考察曝气生物滤池在不同停留时间条件下对河道污水中NH3-N的去除效果。结果表明:在城市河道污水NH3-N质量浓度约为8.0 mg/L, HRT分别为29、 39min时,出水NH3-N质量浓度分别降至1.5 mg/L和0.5 mg/L以下;当NH3-N质量浓度约为4.0 mg/L, HRT分别为11、 15 min时,出水NH3-N质量浓度分别降至1.5 mg/L和0.5 mg/L以下。曝气生物滤池可高效去除城市河道污水中NH3-N,并可降解部分CODCr和TP,与加药气浮形成组合工艺处理城市河道污水,可达到消除劣V类水及更高要求。     

臭氧-曝气生物滤池工艺深度处理石化废水

采用臭氧-曝气生物滤池(BAF)工艺对广东某石化废水经一般生化处理后进行深度处理,以提高废水的可生化性,探讨了废水的初始pH、臭氧投加量和催化剂等因素对臭氧氧化的影响,以及曝气生物滤池不同停留时间对废水COD去除率的影响。结果表明,进水COD约60~80 mg/L,臭氧投加量55.56 mg/L,BAF水力停留时间1.5 h,经组合工艺处理后出水COD低于30 mg/L,达到中水回用标准。     

Preparation and properties of poly(Nε,Nε-dicarboxymethyl-l-lysine)

A new ampholytic homopolypeptide, $\text{poly}\text{(N}{}^{\mathrm{\epsilon }}\text{,N}{}^{\mathrm{\epsilon }}\text{-}\text{dicarboxy-methyl-}\text{l}\text{-lysine}\text{)}$, which has one tertiary amino and two carboxyl groups in the side chain has been derived from a hydrochloride salt of poly(L-lysine). The polymer in aqueous solution seems to be in the coil form with locally extended structure (LES) at neutral pH. In both the acidic and alkaline regions, the molar ellipticity of the polymer changes as a result of change in net charge on the side chain. The conformational changes may be from the coil with LES to other coiled forms. 5–7 M NaClO₄ and 80% aqueous methanol induce the α-helix in the polymer at neutral pH. Divalent cations, Cu²⁺ and Ca²⁺, do not induce any remarkably ordered structures such as α-helix or β-structure in the polymer in aqueous solution at any pH. Ultraviolet absorption studies show an absorption peak of the polymer-Cu²⁺ complex near 240 nm. Dependence of the peak intensity on pH at various q values ($\text{q =}\text{[}\text{Cu}{}^{\mathrm{2+}}\text{]}\text{[}\text{residue}\text{]}$) indicates the two steps of the complex formation. At q less than 0.64, the formation is described only with the first step. An average coordination number for Cu²⁺ at the first step was calculated to be about 2 by the method of Mandel and Leyte. The association constant of Cu²⁺ with the residue at the step was determined from the absorption data to be far smaller than that for the Cu²⁺-EDTA complex. The second step of the formation occurs in the case of large q but the absorption data for the second step cannot be obtained exactly due to precipitation.     

Wet Milling of Fe/Al/Al2O3 and Fe2O3/Al/Al2O3 Powder Mixtures

Wet milling of Al₂O₃-aluminide alloy (3A) precursor powders in acetone has been investigated by milling Fe/Al/Al₂O₃ and Fe₂O₃/Al/Al₂O₃ powder mixtures. The influence of the milling process on the physical and chemical properties of the milled powders has been studied. Particle refinement and homogenization were found not to play a dominant role, whereas plastic deformation of the metal particles leads to the formation of dislocations and a highly disarranged polycrystalline structure. Although no chemical reactions among the powder components in Fe₂O₃/Al/Al₂O₃ powder mixtures were observed, the formation of a nanocrystalline, ordered intermetallic FeAl phase in Fe/Al/Al₂O₃ powder mixtures caused by mechanical alloying was detected. Chemical reactions of Fe and Al particle surfaces with the atmosphere and the milling media lead to the formation of highly porous hydroxides on the particle surfaces. Hence the specific surface area of the powders increases, while the powder density decreases during milling. The fraction of Fe oxidized during milling was determined to be 0.13. The fraction of Al oxidized during milling strongly depends on the metal content of the powder mixture. It ranges between 0.4 and 0.8.     

Participation of lewis base on vinyl chloride polymerization with Al(C2H5)3CCl4 catalyst system

The polymerization of vinyl chloride has been investigated using an $\text{Al}\text{(}\text{C}{}_2\text{H}{}_5\text{)}{}_3\text{CCl}{}_4$ catalyst system in the presence of various Lewis bases. Effective Lewis bases are γ-butyrolactone, diglyme and diethylenetriamine which are multidentate. The rate of polymerization is dependent not only on the basicity of the Lewis base used but also on a coordination number of one. The latter is the predominant factor. For the effect of polymeric amines, a tentative hypothesis is discussed.     

Sintering of Si3N4-Y2O3-Al2O3

Sintering kinetics of the system Si₃N4-Y2O₃-Al₂O3 were determined from measurements of the linear shrinkage of pressed disks sintered isothermally at 1500° to 1700°C. Amorphous and crystalline Si₃N₄ were studied with additions of 4 to 17 wt% Y₂O₃ and 4 wt% A1₂O₃. Sintering occurs by a liquid-phase mechanism in which the kinetics exhibit the three stages predicted by Kingery's model. However, the rates during the second stage of the process are higher for all compositions than predicted by the model. X-ray data show the presence of several transient phases which, with sufficient heating, disappear leaving mixtures of β ' -Si₃N₄ and glass or β '-Si₃N₄, α '-Si₃N₄, and glass. The compositions and amounts of the residual glassy phases are estimated.     

Synthesis and Characterization of Ti0.33Ta0.33Nb0.33C and Ti0.33Ta0.33Nb0.33CxN1-x Whiskers

Ta_0.33Ti_0.33Nb_0.33C and Ta_0.33Ti_0.33Nb_0.33C _x N_{1− x} whiskers were synthesized via a carbothermal vapor-liquid-solid growth mechanism in the temperature range 900°-1450°C in Ar or N₂. The optimum temperature was 1250°C. Whiskers were obtained in a yield of 70-90 vol%. The whiskers were 0.5–1 µm in diameter and 10–30 µm in length. The starting materials that produced the highest whisker yield were: TiO₂, Ta₂O₅, Nb₂O₅, C, Ni, and NaCl. C was added to reduce the oxides, and Ni to catalyze whisker growth. NaCl was used as a source of Cl for vapor-phase transportation of Ta and Nb oxochlorides and Ti chlorides to the catalyst. The catalyst metal was recycled several times during the synthesis and was transported as NiCl₂( g ) according to thermodynamic calculations. The rate of formation and the chemical composition of the whiskers depended on the synthesis temperature, the choice of catalyst, and the atmosphere. At low temperatures, the whiskers were enriched in Nb and Ta, whereas the Ti content increased with increased synthesis temperature.