Mathematical model for the microbial metabolism of glucose induced enhanced biological phosphorus removal in an anaerobic/aerobic sequential batch reactor

Glucose plays a significant role in enhanced biological phosphorus removal (EBPR). Previous experimental studies have shown that in addition to acetate, glucose can induce and maintain a successful EBPR performance under certain operating procedures. Mathematical modeling of the EBPR metabolism is an important consideration that is necessary to produce a deeper insight into this process. In this study, four anaerobic reactions plus four aerobic reactions with fourteen kinetic constants are structured to describe the dynamic behavior of the key metabolic components in the glucose induced EBPR system. The development of the stoichiometric coefficients for the reactions is based on fundamental biochemical principles. The model describes the dynamics of the important storage compounds, which are considered separately from the active biomass. Sequential batch experiments were performed to find the optimum model parameters using sludges exhibiting stable EBPR from glucose fed system. The maximum specific substrate conversion rate in the glucose model is composed of two factors: the maximum specific rates of glucose direct conversion to PHV (q _gv ^max ) and glucose conversion to glycogen q _gl ^max , which are 14.1 and 699.7 C-mmol/C-mmol·h, respectively. The maximum specific rate of polyphosphate synthesis k _pp ^max is 0.2 P-mmol/C-mmol·h. The model with the best-fit parameters satisfactorily simulates the dynamic behavior of the key components during both anaerobic and aerobic conditions.     

黄腐酸与镰刀菌代谢产物的ESR谱性质的研究

以ESR谱仪为主要工具,配合大骨节病病因研究,进行了有关地区饮水中有机物,主要是腐殖酸的黄腐酸级分和粮食真菌——镰刀菌代谢产物性质的相似性比较研究.结果发现,病区粮食中自由基浓度高于非病区,而尖孢镰刀菌(Fusarium Oxysporum)浸染使玉米粉的自由基浓度增加.在氧化、还原、加热和改变酸碱度等处理过程中,菌粮自由基的ESR谱表现出和黄腐酸同样的变化规律.菌粮水提液经GDX-102树脂吸附后,其ESR谱和pH值的关系表明,镰刀菌代谢产物中的自由基集中于带有酸性基团的分子上.水提液的紫外及荧光光谱和黄腐酸具有一定的相似性,因而推论镰刀苗代谢产物的自由基与黄腐酸一样,都是半醌自由基.最后就这类自由基和大骨节病的关系进行了讨论.     

酸雨损害农作物的对策研究——喷水消除酸雨对农作物的损害

经模拟酸雨处理植物的试验表明,酸雨对植物叶片的直接损害是由于酸雨水滴滞留在叶面引起的。若在雨后2h内喷水(pH7.0±0.2)以驱除滞留在叶面的水滴,叶片则无受害症状,叶绿素含量、生物产量和经济产量所受的影响也将减轻甚至完全不受影响。     

利用毛细管气相色谱法测定水和废水中的丙烯酰胺

本文采用毛细管色谱法建立了水和废水中丙烯酰胺的测定程序。以活性炭柱吸附、浓缩样品中的丙烯酰胺，用甲醇洗脱，洗脱液用FID测定。方法回收率为83．1～99．0％，相对标准偏差为5．34％，检出限为0．016mg／L。     

《立体构成》课程建设中教学方法的改革与实践

本文通过对《立体构成》课程教学对象的分析，探讨了该课程在理论与实践教学环节教学方法的改进。实践证明，这些改进对于充分发掘学生潜力，激发学生的求知欲望，提高教师业务水平，促进《立体构成》课程教学改革具有重要意义。     

辽宁大伙房水库水质变化趋势研究

于1979-2003年调查了大伙房水库理化指标,对水质变化趋势进行了研究。入库和库区水体总氮、总磷含量多年平均分别为1.61mg·l-1和0.036mg·l-1;1.23mg·l-1和0.036mg·l-1,均超过国家地表入库Ⅲ和库区Ⅱ类水质标准。库区其他17项水化指标符合国家地表水库区Ⅱ类标准。大伙房水库水体只受到轻度污染,水质等级为近Ⅱ级,属浮游植物响应型中营养水体。     

厌氧折流板反应器处理玉米秆纤维浆粕废水的研究

采用厌氧折流板反应器 (ABR)处理玉米秆纤维浆粕废水 ,研究了工艺条件和工艺特征。试验结果表明 ,在HRT为 2 4h ,OLR为 6 .5 6kgCOD/m3 ·d条件下 ,ABR能有效处理浓度为 6 5 6 0mgCOD/L的玉米秆纤维浆粕废水 ,COD去除率为 75 .1% ;ABR对负荷冲击有良好的适应性 ,且具有推流式和两相式反应器的双重特点。     

Ozonation of Cationic Red X-GRL in aqueous solution: degradation and mechanism

Ozonation of the azo dye Cationic Red X-GRL was investigated in a bubble column reactor at varying operating parameters such as oxygen flow rate, temperature, initial Cationic Red X-GRL concentration, and pH. The conversion of dye increased with the increasing of pH and oxygen flow rate. As the reaction rate constant and the volumetric mass transfer coefficient increase while the ozone equilibrium concentration decreases with the temperature, there is a minimum conversion of dye at 25 degrees C. The increasing of initial dye concentration leads to a decreasing conversion of dye while the ozonation rate increases. The formation of intermediates and the variation of pH, TOC, and nitrate ion during ozonation were investigated by the use of some analytical instruments such as GC/MS, GC, and IC. The intermediates of weak organic acids lower the pH value of the solution. The probable degradation mechanism of the Cationic Red X-GRL in aqueous solution was deliberated with the aid of Molecular Orbital calculations. The N(12)-C(13) site in Cationic Red X-GRL, instead of the N(6)-N(7) site, is found to be the principal site for ozone cycloaddition in the degradation processes. During the degradation process, among the six nitrogen atoms of Cationic Red X-GRL, one is transferred into a nitrate ion, one is converted into an amine compound, and the remaining four are transformed into two molecules of nitrogen.     

Regression modelling of hourly NOx and NO2 concentrations in urban air in London

Based on hourly measurements of NO_x NO₂ and O₃ and meteorological data, an ordinary least squares (OLS) model and a first-order autocorrelation (AR) model were developed to analyse the regression and prediction of NO_x and NO₂ concentrations in London. Primary emissions and wind speed are the most important factors influencing NO_x concentrations; in addition to these two, reaction of NO with O₃ is also a major factor influencing NO₂ concentrations. The AR model resulted in high correlation coefficients (R > 0.95) for the NO_x and NO₂ regression based on a whole year's data, and is capable of predicting NO₂ (R = 0.83) and NO_x (R = 0.65) concentrations when the explanatory variables were available. The analysis of the structure of regression models by Principal Component Analysis (PCA) indicates that the regression models are stable. The results of the OLS model indicate that there was an exceptional NO₂ source, other than primary emission and reaction of NO with O₃, in the air pollution episode in London in December 1991.     

Integrated assessment for aerobic biodegradability of organic substances

In this paper, the amount of oxygen consumption, end products and activities of microorganisms are considered as the three factors which affect the biodegradability of organic substances in water. Two integrated assessment methods for biodegradability of organic substances, fuzzy clustering integrated assessment and weighted integrated assessment, have been developed. Simultaneously, the detail steps for assessing a new organic substance biodegradability with these two integrated assessment methods are proposed.