O/A/O工艺处理化工综合含氮废水运行优化研究

采用初曝池-兼气池-好氧池( O1/A/O2)工艺处理化肥、季戊四醇生产综合含氮废水,在进水COD、NH4+-N的质量浓度平均分别为624和59.3 mg·L-1时,出水COD在100 mg·L-1以下,平均为34.5 mg· L-1,去除率达93.2％;出水氨氮的质量浓度在15 mg·L-1以下,平均为0.8 mg·L-1,去除率高达98.7％;达到了GB 8978- 1996的一级标准.分析了系统反硝化能力较差、TN去除效率较低的原因,提出应减小硝化液回流比、适当调低O1池DO含量、充分利用厂区季戊四醇废液作为外加碳源等措施.     

一体化A/O反应器处理印染废水的启动研究

对传统A/O工艺的硝化液回流方式和污泥培养方式进行改进,设计一种新型一体化内循环式A/O反应器,并以组合填料和火山岩为微生物载体,预处理后的模拟印染废水为原水,研究该反应器的启动过程。结果表明:进水COD、氨氮分别为205、22.9 mg/L时,A/O系统出水COD、氨氮分别为66.2、2.1 mg/L,降解率分别达到67.6%、90.9%。硝化液内回流比降至80%时,该一体化A/O反应器对模拟印染废水的有机物和氨氮仍有较好的降解作用。     

A/O/O生物膜反应器处理锦纶废水的影响因素

试验采用A／O／O生物膜系统对锦纶废水进行处理,考察了硝化液回流比、水力停留时间、DO和进水COD及TN浓度对系统处理效果的影响。结果表明,当进水COD和TN分别为480-525mg／L和24-26mg／L,硝化液田流比3,单个反应器HRT为3．9h,好氧池Ⅰ和Ⅱ内DO均为3．0mg／L左右时,系统COD和TN去除率分别迭95％和70％,出水氨氮低于1．5mg／L,满足GB8978-96污水综合排放一级标准。     

A/O2/移动床生物膜反应器组合工艺处理炼油废水的中试研究

采用厌氧-好氧-好氧-移动床生物膜反应器(A/O2/MBBR)组合工艺对炼油废水处理进行了中试研究,考察中试装置对炼油废水中的CODCr、氨氮的去除情况及系统的耐冲击负荷能力.研究结果表明,A/O2/MBBR组合工艺出水水质明显优于A/O2工艺出水,MBBR可以提高A/O2工艺的容积负荷率和处理效率,具有处理效率高、停留时间短、抗冲击负荷能力强的特点.     

化肥工业废水处理O/A/O脱氮工艺研究

根据化肥工业废水氨氮含量高、波动大等特点,设计了初曝池-兼气池-好氧池(O/A/O)组合工艺。利用模拟废水考察了水力停留时间(HRT)、溶氧(DO)浓度、硝化液回流比和污泥回流比对除氮效果的影响。在模拟废水实验参数基础上,得出实际运行参数为:污泥回流比100%,硝化液回流比400%,缺氧池DO0.5mg·L~(-1),好氧池DO 3mg·L~(-1)。采用O/A/O组合工艺对化肥工业产生的COD在100~1 100mg·L~(-1)、氨氮在20~130mg·L~(-1)范围波动的实际废水进行处理,出水COD均值为35.5mg·L~(-1),出水氨氮均值为1mg·L~(-1),达到《综合污水排放标准》(GB 8978-1996)的一级标准。该技术具有较好的推广应用价值。     

O1/A1/O2/A2工艺处理焦化废水试验研究

通过对短程硝化反硝化工艺的研究,开发了好氧/厌氧/好氧/缺氧(O1/A1/O2/A2)生物脱氮新工艺并用于焦化废水的处理。考察了NH4+-N、COD、TN对反应器运行效果影响。结果表明,当进水COD平均为3 012.9 mg/L,NH4+-N、TN、挥发酚、总氰平均质量浓度分别为590.5、608.4、361.8、34.5 mg/L;出水COD平均为81.7 mg/L,出水NH4+-N、TN、挥发酚、总氰的平均质量浓度分别为0.1、9.9、0.1、0.1 mg/L,出水指标达到国家污水综合排放一级标准,A/O工艺处理这种焦化废水TN偏高,而用O1/A1/O2/A2工艺可以解决这一问题,实现了TN脱除。考察了温度、DO、pH对短程硝化影响。结果表明,在DO质量浓度为1.0～1.5 mg/L、温度在30～35℃、pH 7.5～8.0,系统能够进行稳定短程硝化反硝化。     

A~2/O工艺反硝化除磷试验研究

在A2/O工艺中,通过调节混合液回流比,实现了反硝化除磷菌的富集。COD和氨氮的平均去除率分别为85%和95.6%,达到稳定除磷效果时,磷酸盐的平均去除率为82.9%。缺氧段吸磷量所占比例从27.4%增至65.7%,反应后期平均比值为62.6%。污泥特性实验表明最大缺氧吸磷速率为5.79 mgP/(gMLSS.h),最大好氧吸磷速率为9.29 mgP/(gMLSS.h),两者的比值为62.3%。     

A_2N_2双污泥系统反硝化除磷工艺的启动与稳定

采用低C/N比实际生活污水,以A2N2-SBR(厌氧/硝化/缺氧/硝化)双污泥系统为研究对象,重点考察了A2N2系统启动过程中的脱氮除磷特性。试验结果表明:采用在A2/O-SBR和N-SBR单元分别接种种泥,分开培养驯化聚磷菌污泥和硝化菌生物膜,并利用A2/O-SBR单元的出水作为N-SBR单元的进水,25 d好氧硝化菌生物膜挂膜成功,氨氮去除率稳定在93%以上;A2/O-SBR单元采用先厌氧/好氧(A/O)后厌氧/缺氧(A/A)的运行方式,43 d成功培养富集了反硝化聚磷菌(DPAOs),DPAOs占PAOs的67.81%,反硝化除磷率在77.9%以上;启动成功后原水中约73%和13%的COD分别在A2/O-SBR单元的厌氧段和N-SBR单元曝气过程中被去除,系统出水COD、NH+4-N、PO43--P、TN浓度分别为40.6、0、0.4、13.5 mg·L-1,达到国家《城镇污水处理厂污染物排放标准》(GB18918—2002)一级A排放标准。     

微电解-A/O工艺处理电镀废水

采用微电解-A/O工艺处理浙江某电镀厂的废水,重点考察了微电解单元和A/O单元的工艺条件对废水处理效果的影响。微电解时调节电镀废水的pH值至3.0,曝气6h。A/O工艺的最佳条件为:运行温度20℃,曝气时间24h,溶解氧3mg/L,厌氧阶段葡萄糖的投加量1.40g/L,好氧阶段NaHCO3的投加量0.75g/L。采用微电解-A/O工艺处理电镀废水,出水中氨氮、总氮和COD的质量浓度均达到《电镀污染物排放标准》(GB 21900-2008),去除效果显著、稳定。     

高浓度含氟有机合成废水生化处理的试验研究

含氟有机合成废水中有机物和氨氮浓度高 ,酸性强 ,含有氟离子等毒性大的污染物。实现采用缺氧 -好氧 ( A/O)生化处理工艺对该高浓度有机废水的处理效果进行研究。实验证明 :缺氧 -好氧工艺对有机合成废水处理效果良好 ,实验中还证实了同步硝化 -反硝化的存在 ,可以在工艺中取消或减少 A段的回流     

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.     

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.     

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.     

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.