发酵性丝孢酵母处理精炼大豆油废水的工艺优化及动力学分析

在5 L搅拌式反应器内利用发酵性丝孢酵母处理精炼大豆油废水,并采用正交试验优化处理条件,通过极差分析得到精炼大豆油废水生物处理的较佳条件：温度28℃、转速300 r/min、进气量2 L/min和接种量10%。在该条件下运行36 h后精炼大豆油废水的化学需氧量和含油量的去除率分别为97.31%和89.09%,生物量和油脂分别达到9.27 g/L和51.9%。通过Monod、Tessier和Moser模型研究了发酵性丝孢酵母生物量增长和精炼大豆油废水的污染物降解,发现相比于Monod和Moser模型,Tessier模型更适合研究微生物的增长,并建立了发酵性丝孢酵母生物量增长的动力学方程式,所得到的动力学参数可用于评估含油废水生物处理反应器的设计和运行。     

SBR法处理丁二醇废水动力学研究

对高浓度丁二醇生产废水进行了SBR法小型模拟基质浓度降解动力学研究,求取了有关的动力学参数。结果表明Monod方程的修正式能很好地描述丁二醇的降解规律,试验温度下Monod方程的修正式为:v=0.044(S-100)/[5719+(S-100)]。试验数据还表明在停留时间达40h时,丁二醇废水的降解达到稳定。     

SMBR中消化反应的动力学研究

在一体式膜生物反应器处理稀土氨氮废水的实验中,为进一步了解一体式膜生物反应器中氨氮降解规律及微生物生长的动力学模型,通过合理的理论推导和实验验证,得出消化过程中的基质降解的动力学模型,测出了基质降解动力学模型中的相关参数,并推导出了微生物生长的动力学模型。结果表明:氨氮降解符合Monod方程,并从生物膜组成角度,清楚地揭示其生长动力学行为的变化。     

基于Monod方程建立的BOD动力学模型研究

以Monod方程为基础,建立了生化需氧量BOD的—Monod-BOD模型,同时采用差压法测定了生活污水的BOD5。建立的模型与测定的城市污水的BOD5的数据回归分析拟合情况较好,通过与一级动力学模型的残差平方、模型的选用标准（MSC）和相关指数对比结果表明,在描述城市生活污水BOD的降解过程中,Monod-BOD模型均要优于传统一级动力学,所建模型可以用于生活污水中有机物降解过程的描述。     

纳米TiO2可见光催化-SBR组合工艺降解制药废水

以絮凝为预处理和后续处理工艺,以"纳米TiO2可见光催化-SBR"为组合主体工艺处理制药废水。通过对组合工艺1(絮凝、光催化、SBR、絮凝、出水)和组合工艺2(SBR、絮凝、光催化、絮凝、出水)处理制药废水效果的比较分析可知,组合工艺1的处理效果要高于组合工艺2,主要是因为TiO2光催化预处理反应不仅可以去除一定量的COD,降低原制药废水的负荷,还可有效改善原废水的可生化性和生物毒理性,为后续SBR生物处理提供适宜的处理水质。对光催化降解制药废水的动力学研究表明,光照强度越高,其光催化降解反应遵循二级反应动力学,随着光照强度的减弱,其光催化降解反应趋向于三级反应动力学。     

MBR处理制药废水中动力学参数测定

根据膜生物反应器的特点,利用Lawrence-McCarty模式建立了膜生物反应器处理废水时的污泥增殖动力学模型和底物降解动力学模型,并根据MBR处理诺氟沙星制药废水的试验运行数据计算出了动力学常数Y、Kd、Vmax、和Ks,分别为0.31、0.01、0.32、270.22。     

固定式填充复合床光催化反应器降解实际工业废水特性的研究

设计了一种固定式填充复合床光催化反应器,在该反应器中,对印染、制药和造纸3种实际难降解有机工业废水的光催化降解特性进行了研究.研究结果表明:其对印染、造纸废水中COD.的光催化降解符合零级反应动力学模式,而制药废水中CODcr的光催化降解存在着复杂的动力学模式;650 W紫外光照240 min,3种废水的BOD5/COD0均提高到0.5以上.     

硅橡胶膜生物反应器降解甲苯的细胞生长动力学

用新型硅橡胶膜生物反应器和假单孢菌(Pesudomonas putida mt-2)作为降解微生物,研究了溶解于废水中的甲苯的生物降解。实验测定了废水中甲苯的浓度,培养液中的细胞浓度和溶解氧浓度等。根据废水中甲苯浓度变化计算出的甲苯降解率在废水对培养液流量比为200/100mL h-1时达到93%,根据细胞浓度变化和甲苯浓度变化计算出的细胞比产率在流量比为30/100mL h-1时达到0.00221OD660 (mg L-1) -1。对细胞生长情况进行的分析表明,Monod方程难于描述这种反应器中的细胞生长动力学表现。在关于膜传质动力学问题研究的基础上,通过质量平衡方法构造了一个关于细胞生长的反应动力学模型,用模型进行的细胞生长理论计算与实验结果有较高的吻合程度。     

UV-Fenton法处理皂素生产废水的动力学研究

研究了用UV-Fenton法处理皂素废水的宏观动力学模型。试验证明,UV-Fenton法处理皂素废水的曲线符合三级反应动力学。通过对试验数据进行拟合,得出系统的pH值、反应时间、H2O2投加量和Fe2+浓度对废水中COD降解率的经验模型方程。经过比较动力学模拟的COD出水值与实际运行的测量值,相关性较好,可用于指导实际废水处理。     

基于约氏不动杆菌的萘生物降解特性

萘是典型的多环芳烃,毒害大、难降解,既是重要的环境污染物,又是代表性的石油烃成分,成为各类油污染场地生物修复的难点。碍于其水溶性差而制约了相关研究。利用一株从废油中分离得到的兼具石油烃降解能力和润湿反转无机杂质能力的约氏不动杆菌开展了萘的生物降解特性研究。通过研究降解因素优化出基础的降解条件;在此基础上,在50～2000 mg·L^-1范围内研究了该菌对萘的生物降解特性;并利用Monod模型和Haldane模型对比研究了该菌降解萘的动力学行为。结果表明,该菌在以2000 mg·L^-1萘为唯一碳源的特定条件下,以5%的接种量可以在146 h左右实现萘的全降解;Haldane模型适合于描述菌株的生长和底物降解行为,而Monod模型只适合于描述低浓度下萘的生物降解特性。     

Two-Step Wastewater Treatment: Sequential Ozonation - Aerobic Biodegradation

Ozonation of wastewater from olive related industries has been carried out after dilution with synthetic urban wastewater. The advantages of the application of different acidic and basic cycles during the ozonation process have been shown. Biodegradability of the final effluent measured as the biological oxygen demand to chemical oxygen demand ratio has significantly been increased (100–144% for table olive wastewater and 24–60% for olive oil wastewater). Aerobic biological experiments conducted by using non-acclimated microorganisms confirmed the suitability of the biodegradation after the chemical oxidation pre-treatment. A kinetic model based on a free radical mechanism has been used to simulate experimental results. Both chemical oxygen demand and dissolved ozone concentration profiles are well fitted by the model. The aerobic biodegradation process has been modeled by utilizing the Monod equation.     

丝瓜瓤固定黄孢原毛平革菌对2,4-二氯酚的降解研究

利用植物载体丝瓜瓤对黄孢原毛平革菌进行固定,研究了固定化细胞对2,4-二氯酚的降解性能。利用固定化细胞流化床反应器连续处理质量浓度为20mg/L的2,4-二氯酚废水。考察了不同水力停留时间对处理效果的影响。结果表明,采用吸附生长法能有效实现黄孢原毛平革菌的固定,固定细胞量可达0.791g[细胞]/[丝瓜瓤]。固定化细胞最适降解温度和pH值分别为35℃、6.0。对于质量浓度在20mg/L以下的低浓度2,4-二氯酚,固定化细胞和游离细胞的降解速率相当;对于质量浓度在50～120mg/L的高浓度2,4-二氯酚,固定化细胞具有明显优势,不仅可以耐受更高浓度的2,4-二氯酚,其降解速率也高于游离细胞,最大降解速率是13.95mg/(L·d),是游离细胞的2倍。不同的水力停留时间对固定化细胞流化床反应器连续处理2,4-二氯酚的降解效率有很大影响,固定化细胞对2,4-二氯酚降解过程遵循Monod方程。     

Biodegradation kinetics of benzene,methyl tert‐butyl ether,and toluene as a substrate under various substrate concentrations

Owing to the complexity of conventional methods and shortcomings in determining kinetic parameters, a convenient approach using the nonlinear regression analysis of Monod or Haldane type nonlinear equations is presented. This method has been proven to provide accurate estimates of kinetic parameters. The major work in this study consisted of the testing of aromatic compound‐degrading cultures in batch experiments for the biodegradation of benzene, methyl tert‐butyl ether (MTBE), and toluene. Additionally, batch growth data of three pure cultures (i.e., Pseudomonas aeruginosa YAMT421, Ralstonia sp. YABE411 and Pseudomonas sp. YATO411) isolated from an industrial petrochemical wastewater treatment plant under aerobic conditions were assessed with the nonlinear regression technique and with a trial‐and‐error procedure to determine the kinetic parameters. The growth rates of MTBE‐, benzene‐, and toluene‐degrading cultures on MTBE, benzene, and toluene were significant. Monod's model was a good fit for MTBE, benzene and toluene at low substrate concentrations. In contrast, Haldane's equation fitted well in substrate inhibition concentration. Monod and Haldane's expressions were found to describe the results of these experiments well, with fitting values higher than 98%. The kinetic parameters, including a maximum specific growth rate (µ_m), a half‐saturation constant (K_s), and an inhibition constant (K_i), were given. Copyright © 2007 Society of Chemical Industry     

Development of a mathematical model for the simulation of the biodegradation of organic substrates in a high-solids anaerobic digestion process

A kinetic model is developed to simulate the biodegradation of the organic fraction of municipal solid waste in a high-solids complete-mix continuous-flow anaerobic digestion process. A mass balance correction factor (f) is used to account for (i) the water that is incorporated into the production of biogas, and (ii) the water vapor present in the biogas. With the inclusion of the factor f, expressions are developed to determine the substrate removal efficiency based on first-order and Monod kinetic models. Simulations using first-order and Monod kinetic models are carried out to illustrate the importance of the f factor on the substrate mass removal and microorganism concentration in the high-solids anaerobic digestion process. The effect of the value of f on kinetic constants, and the error involved in considering the high-solids process as a low-solids process are discussed. Finally, experimental results from a pilot-scale high-solids complete-mix batch-fed anaerobic digestion process are used to estimate the first-order rate constant for the biodegradable fraction of municipal solid waste.     

Kinetic Modeling of Styrene Biodegradation by Rhodococcus erythropolis PTCC 1767: Effect of Adaptation to Styrene and Initial Biomass Concentration

Styrene is found at high concentrations in many petrochemical wastewaters and, due to its toxicity, has to be removed from these wastewaters before their discharge. Biological treatment of these wastewaters using pure or mixed microbial cultures that remove styrene through biodegradation has many advantages compared to physic-chemical processes. However, the growth of most of pure or mixed microbial cultures used previously for biodegradation of styrene is retarded at relatively low styrene concentration. In this study, the biodegradation of styrene by Rhodococcus erythropolis PTCC 1767 was considered. The effect of initial biomass concentrations (X), in the range 0.31 gL^?1 and 2.2 gL^?1, and exposure of R. erythropolis to styrene-containing media–on the kinetics of styrene biodegradation was studied.

The results of kinetic showed that, for runs at X?=?2.2 gL^?1, the kinetic data were satisfactorily fitted to the Monod model although the Haldane model gave a better fit of the kinetic data at all initial values of X. The results of kinetic modeling also showed that, with increase in X, the maximum specific removal rate (q_m) decreased whereas the threshold styrene concentration S_threshold increased. On the other hand, the exposure of the bacterial population to successive media in which styrene concentration was increased in a stepwise manner resulted in increase in the values of both q_m and S_threshold. The results of the present study showed the good potential of R. erythropolis for biodegradation of styrene in petrochemical wastewaters, although studies with real petrochemical wastewaters are needed to confirm this potential.     

Steady-state behaviour of an aerobic mixed culture growing on phenol in a continuous stirred reactor

The kinetic behaviour of an aerobic mixed culture was studied in a well-stirred reactor at various dilution rates with phenol as the sole carbon source and limiting factor. In the range of dilution rates investigated (up to 0.51 h⁻¹), biomass washout from the reactor was not observed. Analysis of steady-state data using the inhibitory kinetic parameters obtained in a previous batch growth study gave a very poor prediction of the reactor's performance. Since microbial growth occurred on the reactor walls, the experimental data were analysed using two steady-state equations (one with Monod, the other with Haldane growth kinetics) together with the Topiwala-Hamer model to describe the wall attachment. The mathematical model using Monod kinetics gave a good fit to the experimental data and the values of the kinetic parameters obtained using this model were as follows: maximum specific growth rate, 0.340 h⁻¹; saturation constant, 1.61 mg l⁻¹; wall growth constant, 2.84 mg l⁻¹. Furthermore, the yield and maintenance coefficients were calculated to be 0.47 mg mg⁻¹ and 0.007 mg mg⁻¹ h⁻¹ respectively.