好氧活性污泥法应用于石油化工污水处理的可行性分析

从传统的好氧活性污泥工艺入手,结合石油化工行业污水特点,分析好氧活性污泥法处理石油化工污水的可行性及控制要点。     

微生物法处理巴豆酸生产废水的实验研究

采用微生物法处理巴豆酸生产废水.首先将特定好氧微生物进行驯化,然后用于巴豆酸生产废水的处理,比较了微生物驯化前后巴豆酸生产废水生化降解的效果.当废水的初始COD值小于500 mg·L-1时,直接运用驯化后的好氧微生物处理6h后,COD值可降至30～50 mg·L-1,达到国家《污水综合排放标准》GB 8978-1996...     

关于《化妆品卫生规范》（2007年版）中菌落总数测定方法的探讨

参考《中国药典》微生物检验的验证方法,以金黄色葡萄球菌、枯草芽孢杆菌和大肠埃希菌三株菌为验证菌株,分别采用营养琼脂培养基和卵磷脂、吐温80一营养琼脂培养基,对7个化妆品进行了菌落总数检验方法的验证。结果表明,卵磷脂和吐温8U可以作为中和剂部分消除化妆品中防腐剂的抑菌作用。只有2个样品适用于目前《化妆品卫生规范》2007年版的菌落总数检验方法。对于另外5个样品,分别建立了适合于它们的菌落总数检验方法。     

Real-time control of aerobic/anoxic digestion for waste activated sludge

Experiments were conducted to study the performance characters of aerobic/anoxic(A/A)digestion of sludge at 30±1℃,while the sludge retention time(SRT)was kept 16 d.The variations of oxidation reduction potential(Eh)and pH were continuously monitored during the A/A digestion and the conversions of ammonium and nitrate were investigated.Important features on both Eh and pH profiles were identified to develop process control strategy.Since the feature point on Eh profile where d2 Eh/dt2=0 is very stable during anoxic cycle,it cart be used to determine the end of denitrification.The end of nitrification can be identified according to dpH/dt=0.A real-time control strategy of A/A digestion of sludge was developed and tested with pH and Eh as control parameters.It is shown that the performance of the real-time control strategy is better than that of a fixed-time control strategy.While the real-time controlled A/A digestion system call achieve a similar volatile suspended solids(VSS)destruction efficiency of 35.2% as a continuously aerated system,it improves the superuatant quality in a shorter aeration time(7.75 d for a 20 d period).     

Exercise improves executive function and achievement and alters brain activation in overweight children: A randomized, controlled trial.

Objective: This experiment tested the hypothesis that exercise would improve executive function. Design: Sedentary, overweight 7- to 11-year-old children (N = 171, 56% girls, 61% Black, M ± SD age = 9.3 ± 1.0 years, body mass index [BMI] = 26 ± 4.6 kg/m2, BMI z-score = 2.1 ± 0.4) were randomized to 13 ± 1.6 weeks of an exercise program (20 or 40 min/day), or a control condition. Main Outcome Measures: Blinded, standardized psychological evaluations (Cognitive Assessment System and Woodcock-Johnson Tests of Achievement III) assessed cognition and academic achievement. Functional MRI measured brain activity during executive function tasks. Results: Intent to treat analysis revealed dose-response benefits of exercise on executive function and mathematics achievement. Preliminary evidence of increased bilateral prefrontal cortex activity and reduced bilateral posterior parietal cortex activity attributable to exercise was also observed. Conclusion: Consistent with results obtained in older adults, a specific improvement on executive function and brain activation changes attributable to exercise were observed. The cognitive and achievement results add evidence of dose-response and extend experimental evidence into childhood. This study provides information on an educational outcome. Besides its importance for maintaining weight and reducing health risks during a childhood obesity epidemic, physical activity may prove to be a simple, important method of enhancing aspects of children's mental functioning that are central to cognitive development. This information may persuade educators to implement vigorous physical activity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A compact photomicroreactor design for kinetic studies of gas‐liquid photocatalytic transformations

A compact photomicroreactor assembly consisting of a capillary microreactor and small‐scale light emitting diodes was developed for the study of reaction kinetics in the gas‐liquid photocatalytic oxidation of thiophenol to phenyl disulfide within Taylor flow. The importance of photons was convincingly shown by a suction phenomenon due to the fast consumption of oxygen. Mass transfer limitations were evaluated and an operational zone without mass transfer effects was chosen to study reaction kinetics. Effects of photocatalyst loading and light sources on the reaction performance were investigated. Reaction kinetic analysis was performed to obtain reaction orders with respect to both thiophenol and oxygen based on heterogeneous and homogeneous experimental results, respectively. The Hatta number further indicated elimination of mass transfer limitations. Reaction rate constants at different photocatalyst loadings and different photon flux were calculated. Furthermore, the advantages of this photomicroreactor assembly for studying gas‐liquid photocatalytic reaction kinetics were demonstrated as compared with batch reactors. © 2015 American Institute of Chemical Engineers AIChE J, 61: 2215–2227, 2015     

Modeling and simulation of the formation and utilization of microbial products in aerobic granular sludge

A mathematical model is established to simulate the formation of extracellular polymeric substances (EPS), soluble microbial products (SMP), and internal storage products (X_STO) in aerobic granular sludge. The sensitivity of these microbial products concentrations toward the key model parameters is analyzed. Independent experiments are conducted to find required parameter values and to test its predictive ability. The model is evaluated by using one‐cycle operating experimental results of a lab‐scale aerobic granule‐based sequencing batch reactor (SBR) and batch experimental results. Results show that the model is able to describe the microbial product dynamics in aerobic granules and provide further insights into a granule‐based SBR. The effect of the initial substrate and biomass concentrations on the formation of microbial products in aerobic granular sludge can therefore be analyzed by model simulation. A higher substrate concentration results in a greater concentration of EPS, SMP, and X_STO. An accumulation of biomass in the bioreactor leads to an increased production rate of EPS, SMP, and X_STO. © 2009 American Institute of Chemical Engineers AIChE J, 2010     

The relationship of silage temperature with the microbiological status of the face of corn silage bunkers

A method is proposed to quantify aerobic deterioration of corn silage forage quality as related to the temperature of silage mass in the bunker. Aerobic deterioration, apart from causing nutritional value losses, affects the hygienic quality of silages through the accumulation of pathogenic organisms and their toxins. A survey was carried out in northern Italy that involved a detailed examination of silage bunker from each of 54 dairy farms. Samples from the core, the peripheral areas within 1 m from the silo walls, and the molded spots, when present, were collected. The sample and silage temperatures across the working face were measured at depths of 200 mm at 11 locations and at 7 elevations. The temperature of the central zone of the silo was defined as the reference temperature (T_ref40). The difference between the temperature of the silage sample and the T_ref40 was used as a heating index associated with aerobic deterioration (dT_ref40). The working face area with visible molds was measured. The samples were analyzed for DM content; pH; water activity; nitrates; lactic, acetic, and butyric acids; and microbiological count of yeasts, molds, and clostridia spores. The core samples always showed a pH below 4.0 and a dT_ref40 below 2°C, whereas the silages from the peripheral areas were split into 2 groups, one that had a pH lower than 4 and a dT_ref40 lower than 3.5°C (53%) and one that had a pH higher than 4 and a dT_ref40 higher than 5°C (47%). Most of the silages from the peripheral areas (94%) and all the silages from the moldy spots that have a dT_ref40 above 5°C had a pH higher than 4.5. Furthermore, a positive dT_ref40 higher than 5°C corresponds to a higher yeast count than 5 log cfu/g in most of the silages from the peripheral areas (93% of samples) and in almost all the silages from the molded spots. The evaluation of the extension of the visible molded areas combined with temperature measurement at 200 mm behind the feed-out face could offer a good indication of the health status of silage during consumption. Furthermore, this method could be useful to detect early stages of the aerobic deterioration process and to improve silage management.