Modeling of a sequencing batch reactor treating municipal wastewater using multi-layer perceptron and radial basis function artificial neural networks

A sequencing batch reactor was modeled using multi-layer perceptron and radial basis function artificial neural networks (MLPANN and RBFANN). Then, the effects of influent concentration (IC), filling time (FT), reaction time (RT), aeration intensity (AI), SRT and MLVSS concentration were examined on the effluent concentrations of TSS, TP, COD and NH₄⁺-N. The results showed that the optimal removal efficiencies would be obtained at FT of 1 h, RT of 6 h, aeration intensity of 0.88 m³/min and SRT of 30 days. In addition, COD and TSS removal efficiencies decreased and TP and NH₄⁺-N removal efficiencies did not change significantly with increases of influent concentration. The TSS, TP, COD and NH₄⁺-N removal efficiencies were 86%, 79%, 94% and 93%, respectively. The training procedures of all contaminants were highly collaborated for both RBFANN and MLPANN models. The results of training and testing data sets showed an almost perfect match between the experimental and the simulated effluent of TSS, TP, COD and NH₄⁺-N. The results indicated that with low experimental values of input data to train ANNs the MLPANN models compared to RBFANN models are more precise due to their higher coefficient of determination (R²) and lower root mean squared errors (RMSE) values.     

Characterization of microbial communities from coastal waters using microarrays

Molecular methods, including DNA probes, were used to identify and enumerate pathogenic Vibrio species in the Chesapeake Bay; our data indicated that Vibrio vulnificus exhibits seasonal fluctuations in number. Our work included a characterization of total microbial communities from the Bay; development of microarrays that identify and quantify the diversity of those communities; and observation of temporal changes in those communities. To identify members of the microbial community, we amplified the 16S rDNA gene from community DNA isolated from a biofilm sample collected from the Chesapeake Bay in February, 2000. The resultant 75 sequences were 95% or more similar to 7 species including two recently described Shewanella species, baltica and frigidimarina, that have not been previously isolated from the Chesapeake. When the genera of bacteria from biofilm after culturing are compared to those detected by subcloning amplified 16S fragments from community DNA, the cultured sample exhibited a strong bias. In oysters collected in February, the most common bacteria were previously unknown. Based on our 16S findings, we are developing microarrays to detect these and other microbial species in these estuarine communities. The microarrays will detect each species using four distinct loci, with the multiple loci serving as an internal control. The accuracy of the microarray will be measured using sentinel species such as Aeromonas species, Escherichia coli, and Vibrio vulnificus. Using microarrays, it should be possible to determine the annual fluctuations of bacterial species (culturable and non-culturable, pathogenic and non-pathogenic). The data may be applied to understanding patterns of environmental change; assessing the health of the Bay; and evaluating the risk of human illness associated with exposure to and ingestion of water and shellfish.     

单级与两级序批式反应器用于牛场污水处理的比较研究

对序批式反应器 (SBR)的特点进行了简要的介绍。研究了水力停留时间和有机负荷率对单级和两级SBR用于牛场污水处理时污染物去除率和出水水质的影响 ,并对单级和两级SBR的污水处理性能进行了比较。研究结果表明 ,当用单级SBR处理 10 0 0 0mg LCODCr的污水时 ,1d水力停留时间即可获得较好的处理效果 ,但出水中仍含有一定量的氨。两级SBR可使用较短的水力停留时间而获得较高的污染物去除率和较好的出水水质 ,并可通过硝化过程实现氨的完全的去除     

我国城市生活污水处理方法述评

城市化和工业化进程的加快，生活污水污染日趋严重，制约了社会经济的可持续发展。本文提出了城市生活污水处理规模和工艺的选择原则。论述了主要工艺方案的优选方法。就技术引进、工序和设备的省略、进水标准的确定，以及建设资金筹集和经营模式等专题，提出了建议和对策。     

SBR滗水器的结构原理及应用

文中系统讲述了SBR旋转式滗水器的结构、工作原理及运行特点，列举了SBR旋转式滗水器的应用实例，使人们对SBR旋转式滗水器有更深的认识，使这种新型的污水处理设备得到更广泛的应用。     

SBR在城市污水处理中的发展与应用

研究了SBR工艺类型及发展，分析了SBR的工艺优缺点和设计方法，探讨了SBR在发展中的问题。     

大气环境质量综合评价加权灰色关联模型的建立与应用

利用灰色理论建立大气环境质量综合评价加权灰色关联模型 ,运用污染贡献率确定权重系数。与其它评价模型相比 ,加权灰色关联模型还具有排序功能 ,实例表明该模型是简便有效的     

低DO与化学控制相结合的半亚硝化运行

针对厌氧氨氧化工艺（ANAMMOX）的进水需求以及污水中氮素的存在形态,增强前置半亚硝化工艺的运行稳定性是十分有必要的。研究发现：在温度（30±1）℃、进水pH在8.0以上、DO在0.3 mg·L-1左右、HRT=8 h的情况下;逐步增加进水氨氮（NH4+-N）与碳酸氢盐浓度,经过19 d成功启动亚硝化反应（以亚硝硝酸盐积累率达到50%为限）;为了进一步提升亚硝酸盐积累率,间歇投加5 mmol·L-1氯酸钾,后又改加联氨作为硝化反应的选择性抑制剂,经过大约90 d的反复调试运行,使得出水中NH4+-N与亚硝态氮（NO2--N）的摩尔比近似1：1,基本符合厌氧氨氧化工艺进水需求。通过Miseq测序结果发现：氨氧化菌（AOB）在添加氯酸钾之后,已经成为绝对优势菌种,所占比例为54.99%;在添加联氨之后,AOB所占比例能够达到63.92%,其中包括Nitrosomonas sp和Nitrosomonas europaea这两种亚硝化菌;只有痕量亚硝酸盐氧化菌（NOB）的存在。     

COD降解菌剂的构建及在污水处理中的评估

采用微生物育种技术,从活性污泥中分离筛选得到活性菌株,结合微生物生态学原理,对高效去除污水中COD的复合菌剂构建原则进行探究。通过考察单菌的COD去除效果与絮凝效果,获得7株菌。分别在SBR和A/O模拟系统中进行验证,按COD-03比例复合时,SBR系统出水COD从300 mg·L-1降到约120 mg·L-1（进水COD 1 200 mg·L-1）,较其他组具有极显著性降低（α=0.01）;A/O系统出水COD从约500 mg·L-1降到将近100 mg·L-1（进水COD 1 200 mg·L-1）。结果表明,复合菌剂构建策略具有良好的应用性和可操作性,在COD微生物增效菌剂制备方面具有良好可行性。