实际生活污水快速培养好氧颗粒污泥的方法研究

采用序批式活性污泥法(Sequencing Batch Reactor,SBR),通过接种絮状污泥研究逐级改变进水组成(配水与实际生活污水的比例)实现好氧颗粒污泥快速培养,同时考查了好氧颗粒污泥培养过程中颗粒污泥的物理性质及对污染物的去除效果。结果表明:在好氧颗粒污泥培养初期通过添加营养物质并逐渐增加实际生活污水的比例可以实现好氧颗粒污泥的快速培养,与完全用配水培养的好氧颗粒污泥基本相似,且培养出的好氧颗粒污泥结构密实,湿密度为1.046 g/cm3,比重为1.025,平均沉降速度为38.67 m/h,粒径在1 mm左右,颜色为黄褐色;同时培养的颗粒污泥对污染物有较好的处理效果,COD、NH+4-N的去除率分别高达85%、90%。培养初期在实际生活污水中通过添加营养物质能够诱导好氧颗粒污泥形成,实现好氧颗粒污泥的快速培养。     

浅谈小区生活污水处理与回用

通过分析小区生活污水的水质、水量特征,系统地介绍了小区生活污水处理工艺和小区生活污水回用技术。     

The 18-week fetal examination and detection of anomalies

From its beginning in the fifties the use of ultrasound in gynaecology and obstetrics has expanded extensively. Ultrasound technology has taken us from a time when the mother was our prime focus to the present where it is the unborn baby. Ultrasound assessments may have significant consequences for pregnancy care by optimizing the time, the mode and the location of the delivery as well as preparing the postnatal staff for a prenatally defined fetal problem. A major factor in the development was the groundbreaking work of an obstetrician, Ian Donald, and an engineer, Tom Brown, at Queen Mother's Hospital in Glasgow, who produced an ultrasound instrument called the Diasonograph. The first screening program offering a systematic ultrasound examination to a large pregnant population began in Malmoe, in 1973 and aimed to detect twins. Since then the examination has evolved over the years to include a systematic evaluation of the intrauterine contents. A number of randomized controlled trials have been reported and several large studies have reported the efficiency of routine fetal examinations for the detection of anomalies. Detection rates for the various subsets are presented. The learning curve regarding the ability to detect anomalies and the importance of proper training has also been shown. The procedure ‘routine fetal examination’ has been significant in supporting the continuous development of fetal medicine. The consequences of the improved dating of every pregnancy and the in utero transport of a sick fetus rather than an emergency transportation of a sick neonate, have an established evidence base. Ultrasound technology has had a remarkable ability to trigger great technical minds to move the technology forward year after year. Through a continuous cooperation between technicians and clinicians, this impressive technology of ultrasound will continue to support our work for the unborn child. Copyright © 2010 John Wiley & Sons, Ltd.     

The optimal harvest and management in the models of animal populations

We extended zero-cost optimization model for population of domestic animals. Also the model of hiring of labor in cattle-breeding farm is constructed and investigated.     

Identifying Sighting Clusters of Endangered Taxa with Historical Records

Abstract: The probability and time of extinction of taxa is often inferred from statistical analyses of historical records. Many of these analyses require the exclusion of multiple records within a unit of time (i.e., a month or a year). Nevertheless, spatially explicit, temporally aggregated data may be useful for identifying clusters of sightings (i.e., sighting clusters) in space and time. Identification of sighting clusters highlights changes in the historical recording of endangered taxa. I used two methods to identify sighting clusters in historical records: the Ederer–Myers–Mantel (EMM) test and the space–time permutation scan (STPS). I applied these methods to the spatially explicit sighting records of three species of orchids that are listed as endangered in the Republic of Ireland under the Wildlife Act (1976): Cephalanthera longifolia, Hammarbya paludosa, and Pseudorchis albida. Results with the EMM test were strongly affected by the choice of the time interval, and thus the number of temporal samples, used to examine the records. For example, sightings of P. albida clustered when the records were partitioned into 20‐year temporal samples, but not when they were partitioned into 22‐year temporal samples. Because the statistical power of EMM was low, it will not be useful when data are sparse. Nevertheless, the STPS identified regions that contained sighting clusters because it uses a flexible scanning window (defined by cylinders of varying size that move over the study area and evaluate the likelihood of clustering) to detect them, and it identified regions with high and regions with low rates of orchid sightings. The STPS analyses can be used to detect sighting clusters of endangered species that may be related to regions of extirpation and may assist in the categorization of threat status.     

A room for living: Private and public aspects in the experience of the living room

This paper presents findings from a study on people's uses and experiences of their living rooms. The researcher conducted in-depth interviews with sixteen middle-class residents of the Metropolitan New York area. Interviews were conducted in participants' living rooms, and were supplemented by observations, sketches and still-photographs. In the past, social scientists have viewed the living room as serving the purpose of communicating the dwellers' image to guests. Findings from the present study show that dwellers may use their living rooms not only to host guests, but also for their own solitary uses, as well as for sharing time with partners. All uses were found to be meaningful and pertinent to the dwelling experience. Findings also reveal that the living room may provide opportunities for intimacy between dwellers and their partners, as well as between dwellers and their guests. For all participants living rooms contained objects that were highly meaningful to them. It is suggested that objects in the living rooms are used to instigate and mediate contemplation about significant others, as well as to regulate the amount of intimacy desired with guests.     

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.