Seismic vulnerability assessment of water supply network in Tianjin,China

The water supply network （WSN） system is a critical element of civil infrastructure systems. Its complexity of operation and high number of components mean that all parts of the system cannot be simply assessed. Earthquakes are the most serious natural hazard to a WSN, and seismic risk assessment is essential to identify its vulnerability to different stages of damage and ensure the system safety. In this paper, using a WSN located in the airport area of Tianjin in northern China as a case study, a quantitative vulnerability assessment method was used to assess the damage that the water supply pipelines would suffer in an earthquake, and the finite element software ABAQUS and fuzzy mathematic theory were adopted to construct the assessment method. ABAQUS was applied to simulate the seismic damage to pipe segments and components of the WSN. Membership functions based on fuzzy theory were established to calculate the membership of the components in the system. However, to consider the vulnerability of the whole system, fuzzy cluster analysis was used to distinguish the importance of pipe segments and components. Finally, the vulnerability was quantified by these functions. The proposed methodology aims to assess the performance of WSNs based on pipe vulnerabilities that are simulated and calculated by the model and the mathematical method based on data of damage. In this study, a whole seismic vulnerability assessment method for a WSN was built, and these analyses are expected to provide necessary information for a mitigation plan in an earthquake disaster.     

Improvement of nitrification efficiency by bioaugmentation in sequencing batch reactors at low temperature

Bioaugmentation is an effective method of treating municipal wastewater with high ammonia concentration in sequencing batch reactors （SBRs） at low temperature （10℃）. The cold-adapted ammonia- and nitrite- oxidizing bacteria were enriched and inoculated, respectively, in the bioaugmentation systems. In synthetic wastewater treatment systems, the average NH4＋-N removal efficiency in the bioaugmented system （85%） was much higher than that in the unbioaugmented system. The effluent NH4＋ -N concentration of the bioaugmented system was stably below 8 mg. L1 after 20 d operation. In municipal wastewater systems with bioaugmentation, the effluent NH4＋- -N concentration was below 8 mg·L^-1 after 15 d operation. The average NH4＋ -N removal efficiency in unbioaugmentation system （about 82%） was lower compared with that in the bioaugmentation system. By inoculating the cold-adapted nitrite-oxidizing bacteria （NOB） into the SBRs after 10 d operation, the nitrite concentration decreased rapidly, reducing the NO2 -N accumulation effectively at low temperature. The func- tional microorganisms were identified by PCR-DGGE, including uncultured Dechloromonas sp., uncultured Nitrospira sp., Clostridium sp. and uncultured Thauera sp. The results suggested that the cold-adapted microbial agent of ammonia-oxidizing bacteria （AOB） and NOB could accelerate the start-up and promote achieving the stable operation of the low-temperature SBRs for nitrification.     

Assessing the potential of crop residue recycling in China and technology options based on a bottom-up model

Crop residues are an important biomass, and are significant in the sustainable development of China. This paper uses the Grey-Markov modeling approach, the cost-benefit analysis method, and the constraint optimiza- tion method to establish the potential of crop residue recycling in China （CRRC） using a bottom-up analysis. Taking 2010 as the baseline year, the CRRC model is used to determine the quantity trends of crop residue resources, simulating the recycling potential and selecting key crop residue recycling technologies for operation between 2010 and 2030. The results illustrate that the total residue output from different crops will gradually increase to 1062 million tons in 2030. The proportion of crop residue for field burning is expected to decrease as a result of guidance and support from the government. Market mechanisms are also improving the development of the crop residue recycling industry. The economic benefit of crop residue recycling is expected to be worth 132 billion CNY in 2030 according to technology structure options. Key crop residue recycling technologies preferred such as liquefaction, amination, silo, co-firing straw power and composting will account for more than 85% of the total benefits.     

Mycelial culture of wild Inonotus hispidus parasitizing the jujube tree and the cultivation conditions of its fruit body on rice medium北大核心CSCD

Inonotus hispidus is a kind of rare medicinal fungus, and its natural resources are very scarce. Currently, the artificial cultivation technology of I. hispidus is not completely developed, and this reflects on its extremely low biological conversion rate and long cultivation period. In order to improve the bioconversion rate and shorten the production cycle of I. hispidus, we first analyzed the mycelia culture conditions of the collected I. hispidus, and then we further explore the method of domesticated cultivation of its fruiting body in rice medium. During the process of mycelial culture, the suitable temperature, pH, carbon source, and nitrogen source for mycelial growth were selected using the mycelial growth rate as index. During the domesticated cultivation of the fruiting body, the suitable culture medium for its growth was selected using the bioconversion rate as index. Screening results of mycelial culture conditions showed that the optimal culture conditions for the growth of mycelium of the wild I. hispidus were: temperature of 25 °C, initial pH of 6.0, glucose as the carbon source, and yeast extract powder as the source of nitrogen. The results of the domesticated cultivation showed that the biotransformation rate of I. hispidus was higher when using rice as the main medium substrate. The optimal cultivation conditions were: a 0.2% yeast extract content in the nutrient solution, a 1:1.6 ratio of rice to nutrient solution, and a 4 mL inoculum of the liquid strain. Under these conditions, it took about 4 days for the mycelium to grow over the cultivation medium. The time required for the differentiation of the primordium to form fruit bodies was about 20 days, and the bioconversion rate reached 28.70% ± 5.05%. The results of this study indicate the feasibility of using rice as the main substrate for the cultivation of I. hispidus, and it also provide new insights for the finding of new cultivation substrates for other rare medicinal fungi. © 2018 Science Press. All rights reserved.     

Microbial fuel cell with three-dimensional electrodes for domestic wastewater treatment and electricity generation北大核心CSCD

A single chamber microbial fuel cell (MFC) with three-dimensional electrodes packed bed carbon felts was developed to treat domestic wastewater while simultaneously generating electricity. The influence of batch and continuous operation mode on treatment effectiveness and electricity production of the MFC was investigated to provide a reference for the application of the MFC. The MFC with a total working volume of 1 440 mL was operated in the fed-batch mode for 5 d repeatedly three times, and then shifted to the continuous mode. During the testing of the continuous mode, wastewater was continuously pumped into the anode compartment at a flow rate of approximately 0.2 mL/min, resulting in a hydraulic retention time of 5 d. During the batch test, the MFC obtained 91.1% chemical oxygen demand (COD) and 98.2% NH4 +-N removal, which accorded with the first criteria specified in the discharge standard of pollutants for municipal wastewater treatment plants in China (GB18918-2002). A maximum power density of 27.88 mW/m3 was achieved at a 51 Ω external resistor. During the continuous test, the COD removal efficiencies ranged from 83.2% to 97.4%. The concentration of NH4 +-N gradually decreased within 5 d and was then maintained below 9.45 mg/L, thus an enhanced removal performance of NH4 +-N was acquired. However, a low removal efficiency of total nitrogen was observed owing to the accumulation of NO3 --N in the effluent since day 11. Additionally, the MFC continually generated electricity with a maximum power density of 582.5 mW/m3 and average output voltage of 0.087 7 V during the stable period in the continuous operation mode. Moreover, 16S rRNA gene high-throughput sequencing showed that Thauera sp., Saprospiraceae-UN sp., and OPB56-UN sp. were identified as dominant populations. The results suggested that the organic matter associated with power generation was constantly utilized by the microorganisms in the reactor, which caused an excellent electricity generation performance during the continuous test. Therefore, the continuous operation mode could improve the low output voltage phenomenon in the MFC. Thauera sp., as a type of nitrate-reducing bacteria, was enriched in the autotrophic denitrifying microbial communities; therefore, bio-enrichment with denitrifying bacteria such as Thauera sp. could decrease the concentration of NO3 --N in the effluent during the continuous operation mode, which is expected to be an innovation for improvement of wastewater treatment. © 2018 Science Press. All rights reserved.     

Effect of seawater salinity on the synthesis of zeolite from coal fly ash

A novel method for the synthesis of zeolite was developed in this paper. The synthesis was carried out by hydrothermal activation after alkali fusion and coal fly ash （CFA） was used as raw material with seawater of different salinities. Seawater salinity was varied from 32 to 88 for zeolite crystallization during the hydrothermal process. The results show that seawater salinity plays an important role in zeolite synthesis with CFA during hydrothermal treatment. The products were a mixture of NaX zeolite and hydroxysodalite; seawater salinity more strongly affected the crystallization than the type and chemical composition of the zeolites. The yield of CFA transformed into zeolite gradually rose with the increase in salinity, reaching a transformation rate of 48%--62% as the salinity increased from 32 to 88, respectively. The proposed method allows for the efficient disposal of by-products; therefore, the application of seawater in zeolite synthesis presents promising economic and ecological benefits.     

Interaction between Humic Acid and p-Arsanilic Acid Using Fluorescence Quenching Approach

P-arsanilic acid(p-ASA),as a kind of organoarsenic feed additive,has been widely used in poultry and swine breeding.However,it has caused the arsenic pollution around the farm.Currently data shows humic acid(HA)is closely to the migration and transformation of p-ASA.Therefore,the interaction between p-ASA and HA was investigated by using the method of fluorescence quenching titration.The association constant changed from2.74 to 4.88 L·mol-1at a p H varying from 5 to 9 and reached the maximum at p H 7.In addition,log K varied from4.15 to 5.02 L·mol-1when the temperature increased from 15℃to 35℃.The log K increased with an increase in the concentration of HA.The dominant mechanism between p-ASA and HA is static quenching.The primary interaction force was likely the hydrogen bond,and the binding behavior occurred on the As-O stretch of p-ASA and the carboxylic acid C=O stretch of HA.The results showed that dissolved organic matters could affect the fate and biogeochemical cycling of organoarsenic pharmaceuticals in aquatic ecosystems.     

Inhibitory kinetics of β-N-acetyl-D-glucosaminidase from Nile tilapia (Oreochromis niloticus) by cadmium北大核心CSCD

Cadmium (Cd2+) pollution in an aquatic environment can negatively affect certain reproductive parameters of aquatic animals. β-N-acetyl-D-glucosaminidase (NAGase) is considered to play an important role in the fertilization process. The aim of the present study was to investigate the effect of Cd2+ on the activity of NAGase purified f rom the testis of Nile tilapia, toward contributing new knowledge on the breadth of negative effects of Cd2+ for Nile tilapia production. The kinetic method of substrate reaction was used for this assessment, and an inhibitory model was established to study the kinetics of NAGase under inhibition by Cd2+. The results showed that Cd2+ could reversibly inhibit the enzymatic activity of NAGase, and the half-maximal inhibitory concentration was estimated to be 40.95 mmol/L. Cd2+ was found to be a competitive inhibitor of NAGase, and the inhibitory constant was determined to be 17.13 mmol/L. The microscopic rate constants of inactivation were also determined. Together, these findings demonstrate that Cd2+ is a reversible inhibitor that can competitively inhibit NAGase. These results may provide a theoretical foundation for further studies on the reproduction of tilapia. © 2018 Science Press. All rights reserved.     

Isolation,identification, culture conditions,and laccase production of white rot fungus北大核心CSCD

The white rot fungi are members of Basidiomycota, which can degrade lignin and form white rot. They are high producers of extracellular laccases. In the present study, pure culture strain of high-temperature and high-laccase production types (numbered as BUA-01) was isolated from the fruiting bodies of a white rot fungus collected in the campus of Beijing University of Agriculture. The taxonomic characteristic was determined based on morphological and ITS sequence analysis. Furthermore, the optimal culture conditions for the mycelia were determined, including carbon source, nitrogen source, C/N ratio, growth factors, temperature, and pH. Extracellular laccase production was investigated in liquid fermentation with different concentrations of Cu (CuSO4) as inducer. Decolorizing activity of the fermentation broth was assayed using three azo dyes: Evans blue, methyl orange, and eriochrome black T. The results showed that the strain possessed the highest homology toward Trametes hirsuta, with the homology ratio of 100% and the genetic distance of 0, suggesting that the strain BUA-01 belonged to the genus Trametes. The culture condition investigated revealed that the optimal condition for mycelia growth included the following: carbon source, starch; nitrogen source, soybean powder and yeast extract; C/N ratio, 40/1 and 10/1; temperature, 37 °C; and pH, 6.0-7.0. The assayed growth factors had no significant effect on mycelial growth. It demonstrated high laccase activity in liquid fermentation. The highest extracellular laccase activity of 1 081.33 ± 6.3 U/mL was observed in the broth with a Cu adjunction concentration of 0.25 mmol/L after a 96-h culture period. It was about 26-fold higher than that of the control group. The isolated strain exhibited significant decolorizing activity toward the azo dyes Evans blue, methyl orange, and eriochrome black T, with the decolorization rate at 12 h of 93.31% ± 0.16%, 92.37% ± 0.42%, 79.25% ± 0.64%, respectively. This suggests that the strain possesses potential applications in laccase production and dye degradation. © 2018 Science Press. All rights reserved.     

油井采出液中硝酸盐还原菌的分离培养及对硫酸盐还原的抑制

采用油井采出液培养基和加入无机盐成分的改良油井采出液培养基,对大庆油田萨北过渡带油井采出液中的细菌进行分离培养及初步鉴定,比较了两种情况下培养出的具有硝酸盐和/或亚硝酸盐还原,以及/或反硝化能力菌群结构的差异.利用采出液培养基培养出一组新的微生物菌株,并且分离的硝酸盐和/或亚硝酸盐还原菌,以及/或反硝化细菌(Nitrate/nitrite reducing bacteria,denitrifying bacteria,NRDB)比例明显高于无机盐-采出液培养基;但培养基中无机盐成分的添加,提高了可培养NRDB的群落生物多样性.仅仅向油井采出液中直接投加硝酸盐作为电子受体,对其中硝酸盐还原、亚硝酸盐还原和反硝化微生物(NRDB)的激活作用以及产抑制硫化物产生的能力有限,而同时加入分离自采出液的NRDB和硝酸盐则对硫酸盐还原菌(SRB)的生长和产硫化物活性都产生了明显的抑制.但是NRDB与硝酸盐同时投加对不同SRB的抑制效果并不相同,导致了SRB群落结构的变化.图5表2参17     

Benthic Foraminifera: morphology and growth in clone cultures of Heterostegina depressa

A three months old clone of 76 asexually produced F₂ Heterostegina depressa D'Obbigny, 1826 (Foraminifera) was subdivided into two groups which were cultivated for 5 months, one at 300 lux, the other at 600 lux. Nourishment was provided by symbiotic photosynthesizing algae. The 300-lux group added 1 whorl, the 600-lux group added 1/2 a whorl during the experiment, suggesting that the first group was nearer the optimum for growth than the second. Growth rates reacted but slowly to changes in environmental conditions. Also, specimens within the same culture dish showed great differences in response. In the 600-lux group, many specimens ceased to grow entirely, while others continued. Cessation of growth tends to produce a rounded test shape, by filling-in of the apertural angle, while rapid growth tends to be correlated with flaring tests (i.e., tests with an open spiral). In addition, there is a trend toward increased flaring during normal ontogenetic development. Shell damage is greater in rapidly growing individuals; walls are apparently thicker in slowly growing and in resting individuals. Ecological interpretation of morphological characteristics is hampered by: (1) a lag effect between growth response and environmental change; (2) slowing or termination of growth under stressful conditions with corresponding minor changes in morphology; (3) great variation in response between sibling individuals within the same culture dish; (4) aging effects.     

海藻酸钙固定混合SRB菌群生物吸附Ni^2＋的动力学

利用海藻酸钙为载体包埋固定化硫酸盐还原菌(SRB)混合菌群,研究了固定化微生物吸附重金属镍离子的动力学特性.结果表明:固定化混合SRB菌群对Ni2 具有良好的吸附性能,最大吸附容量qm高达931.9mg(Ni2 )/g(SRB)颗粒,是一种颇具应用前景的生物吸附剂.固定化SRB吸附Ni2 的动力学过程可以用准二次动力学方程描述,整个吸附过程可以明显地分为两个阶段,即物理化学吸附阶段和生物沉淀阶段.扩散动力学研究表明,固定化颗粒的内扩散并非是唯一控制吸附速率的机制,整个吸附过程涉及到多种吸附机制.图4表3参14     

硫酸盐还原菌的生态特性及其应用[综述]

硫酸盐还原菌（ＳＲＢ）是一类形态各异、营养类型多样、能利用硫酸盐或者其他氧化态硫化物作为电子受体来异化有机物质的严格厌养菌．常见属有脱硫弧菌属（Ｄｅｓｕｌｆｏｖｉｂｒｉｏ）,脱硫肠状菌属（Ｄｅｓｕｌｆｏｔｏｍａｃｕｌｕｍ）．因其参与自然界中的多种反应,所以愈来愈得到人们的关注．１　ＳＲＢ的生活环境和条件１．１　ＳＲＢ在环境中的分布［１］自然界中最常见的ＳＲＢ是嗜温的革兰氏阴性、不产芽孢的类型．在淡水及其他含盐量较低的环境中,易分离到革兰氏阳性、产芽孢的菌株．此外,在自然界中存在的还有革兰氏阴性嗜…     

A biofilter model for simultaneous simulation of toluene removal and bed pressure drop under varied inlet loadings

In this study, a biofiltration model including the effect of biomass accumulation and inert biomass growth is developed to simultaneously predict the Volatile Organic Compounds (VOCs) removal and filter bed pressure drop under varied inlet loadings. A laboratory-scale experimental biofilter for gaseous toluene removal was set up and operated for 100 days with inlet toluene concentration ranging from 250 to 2500 mg?m^-3. According to sensitivity analysis based on the model, the VOCs removal efficiency of the biofilter is more sensitive to Henry’s constant, the specific surface area of the filter bed and the thickness of water layer, while the filter bed pressure drop is more sensitive to biomass yield coefficient and original void fraction. The calculated toluene removal efficiency and bed pressure drop satisfactorily fit the experimental data under varied inlet toluene loadings, which indicates the model in this study can be used to predict VOCs removal and bed pressure drop simultaneously. Based on the model, the effect of mass-transfer parameters on VOCs removal and the stable-run time of a biofilter are analyzed. The results demonstrate that the model can function as a good tool to evaluate the effect of biomass accumulation and optimize the design and operation of biofilters.     

Determination of ammonium uptake and regeneration rates using the seawater dilution method

We have developed a method for the determination of ammonium uptake and regeneration rates applying the principle of the seawater dilution technique. The method is based on the separation of uptake and regeneration processes in the dilution series. A model is used to estimate ammonium uptake and regeneration rates simultaneously, in addition to phytoplankton growth and grazing rates. The method was applied to dilution experiments conducted during a two-year study of the upwelling region off Oregon, USA. Ammonium uptake and regeneration rates determined with our method ranged from 0.5 to 3 mol l^-1d^-1 and from 0.2 to 2.9 mol l^-1d^-1, respectively. These values agree well with those from other studies applying ¹⁵N tracer techniques in the same or similar environments. We found a close coupling between ammonium uptake and regeneration, and a strong relationship between ammonium regeneration and grazing rates. In addition, the nutritional status of the phytoplankton community could be assessed by comparing instantaneous ammonium uptake rates with the specific phytoplankton growth rates. Using the dilution technique to determine ammonium uptake and regeneration rates of the plankton community is a promising alternative to the application of tracer techniques conventionally used to determine these rates.     

Development of rapid ammonium uptake during starvation of batch and chemostat cultures of the marine diatom Thalassiosira pseudonana

Cell nitrogen quotas and uptake rates following ammonium additions were measured during ammonium-limited growth transients obtained by starving batch and chemostat cultures of Thalassiosira pseudonana (Clone 3 H). During starvation, cell quotas decreased by more than 50% in batch cultures. In chemostat cultures, the drop in cell quota during starvation decreased with dilution rate, from more than 50% at 1.45 d^-1, to less than 10% at 0.22 d^-1. Minimal levels of 3 to 4×10^-2 pg-at. N cell^-1 were reached after 24 h starvation in both batch and chemostat cultures. Uptake rates over the first minute of perturbation experiments were 3 times the long-term (10 to 30 min) rates. In batch cultures, specific uptake rates increased from 4 d^-1 to 20 d^-1 after 24 h starvation. Uptake rates per cell were independent of starvation time and dilution rate in chemostat cultures, but lower in non-starved batch cultures. The implications of these data for models of phytoplankton growth are discussed: the data support models which predict a depression in average growth rates when diatoms encounter microscale patches in oligotrophic environments.     

Microbial community structure and dynamics of starch-fed and glucose-fed chemostats during two years of continuous operation

The microbial community structures of two mesophilic anaerobic chemostats, one fed with glucose, the other with starch as sole carbon sources, were studied at various dilution rates (0.05–0.25 d^–1 for glucose and 0.025–0.1 d^–1 for starch) during two years continuous operation. In the glucose-fed chemostat, the aceticlastic methanogen Methanosaeta spp. and hydrogenotrophic methanogen Methanoculleus spp. predominated at low dilution rates, whereas Methanosaeta spp. and the hydrogenotrophic Methanobacterium spp. predominated together when dilution rates were greater than 0.1 d^–1. Bacteria affiliated with the phyla Bacteroidetes, Spirochaetes, and Actinobacteria predominated at dilution rates of 0.05, 0.1, and 0.15 d^–1, respectively, while Firmicutes predominated at higher dilution rates (0.2 and 0.25 d^–1). In the starch-fed chemostat, the aceticlastic and hydrogenotrophic methanogens coexisted at all dilution rates. Although bacteria belonging to only two phyla were mainly responsible for starch degradation (Spirochaetes at the dilution rate of 0.08 d^–1 and Firmicutes at other dilution rates), different bacterial genera were identified at different dilution rates. With the exception of Archaea in the glucose-fed chemostat, the band patterns revealed by denaturing gradient gel electrophoresis (DGGE) of the microbial communities in the two chemostats displayed marked changes during long-term operation at a constant dilution rate. The bacterial community changed with changes in the dilution rate, and was erratic during longterm operation in both glucose-fed and starch-fed chemostats.     

Combinatorial effects of distillery and sugar factory effluents in crop plants

Under the reutilization and recycling strategy of industrial effluents, treated distillery and sugar factory mixed effluent was used in petridish culture experiments to investigate its effect on seed germination and seedling growth in wheat, garden pea, black gram and mustard. The seed germination and seedling growth were significantly reduced with increase in concentration of the effluent. The fresh matter was found significantly increased in barley (1.16 g per seedling in 25% dilution level of effluents in comparison to 0.93 in control), while other higher dilution levels reduce it. Wheat, garden pea, black gram, mustard invariably showed inhibition in fresh weight. Dry weight was found consistently reduced or unchanged in different treatments. Total chlorophyll contents in barley were significantly increased in different treatments (2.351 and 2.721 mg/g fresh weight of tissue at 25, 50% dilution levels in comparison to 1.781 of control) while in other crop it was reduced alloverthe treatments. Amylase activity in wheat, garden pea, black gram and mustard was reduced in all the treatments. Only in barley its level was enhanced from 0.76 to 0.85, 0.96, 0.81 in 25, 50, 75% dilution levels of the effluent mixture respectively Based on the data of different crops barley was found to be highly tolerant as the 25 and 50% dilution levels of combined effluents. It showed no change in germination %, while seedling growth was increased in lower dilution levels of combined effluent as compared to control Barley>garden pea>wheat>black gram>mustard gradually showed increased level of sensitivity respectively Most detrimental effects were seen in mustard. This toxicity might be due to excess of nutrients, beyond the limits of tolerance. Therefore, the higher concentration of mixed effluent was not advisable for irrigation purpose, however it could be used for irrigation purpose after proper treatment and dilution (one part treated effluent and five parts of available irrigation water), as this dilution level was found growth and yield promotory     

垃圾渗滤液污染地下水中硫酸盐还原菌种群结构多样性分析

实验样本取自上海老港垃圾填埋场两处受垃圾渗滤液和海水双重污染的地下水监测井.通过PCR扩增异化型亚硫酸盐还原酶(Dissimilatory sulfite reductase,DSR)基因,建立dsrAB基因克隆文库,用系统发育分析的方法研究了两口污染程度不同的地下水监测井水样中硫酸盐还原菌(Sulfate-reducing bacteria,SRB)的种群结构.结果表明,Desulfobacter-aceae在两口地下水监测井G和I井中均占主导地位(分别为40.5%和49.0%),在海水混入比例更高、污染程度更重的I井文库中有40.6%类Desulfobacteraceae克隆子具有嗜盐或适盐性,相比较,G井中有31.0%克隆子具有嗜盐或适盐性.实验还发现,I井中次优势菌群是Syntrophobacteraceae(30.9%),而G井中次优势菌群是Desulfobulbaceae(29.8%).表明海水混入比例和污染程度的不同会导致地下水系统中SRB的种群结构差别.研究结果也体现了老港地下水系统特殊的物理化学环境导致了其与国内外其它垃圾填埋场地下水中主要SRB种群的差别.图2表2参18