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采用包埋法制备出一种复合生物填料,测其各项理化性质,并以NOx模拟废气验证其脱硝性能。填料主要由碳酸钙、牛粪堆肥腐殖质、菌剂载体、水泥、轻质珍珠岩、立体网状纤维及脱硝功能微生物等复合而成,粒径12 mm×20 mm,自然堆积密度(471±0.8)kg/m3,持水量(49±1.3)%,比表面积3.91 m2/g,平均机械强度(427.3±0.2)N,pH为10.5±0.2。填料能长期在潮湿环境中保持良好的粘结强度,并具有营养缓释及pH缓冲能力。包埋脱硝功能微生物复合填料中初期微生物数量5.3 ×105 CFU/g,运行60 d后微生物数量达到8.6×108 CFU/g,闲置停运30 d微生物有所减少,但重启后净化效率基本不变。当进气负荷低于1 878 mg/(m3·h),气体停留时间为14.47 s时,BF1的去除率高达93.15%。 相似文献
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应用PCR-DGGE方法,追踪了汉沽工业废水处理中好氧工艺的活性污泥系统中微生物群落结构动态变化过程及其微生物群落结构组成。研究结果表明:系统中的微生物群落结构随水质变化而变化,随着培养时间的延长,微生物群落结构趋于稳定,分别属于5大类群,与γ、δ、α、ε变形杆菌(Proteobacterias)、芽孢杆菌(Bacilli)的亲缘关系较近。其中γ变形杆菌是该废水处理过程中的主要菌群,包括Pseudomonas sp.、Rheinheimera sp.、Citrobacter sp.、Klebsiella sp.、Enterbacte-riaceae、Stenotrophomonas maltophilia、Acinetobacter。在整个系统中uncultured Pseudomonas sp.、Halobacillus sp.、Pseudomonassp.、Pseudomonas stutzeri、Acinetobacter sp.可稳定存在于系统中,为该污水处理系统中的优势微生物。因此,提高Halobacillussp.、Pseudomonas sp.、Pseudomonas stutzeri、Acinetobacter sp.菌属在系统中的数量和质量,有利于提高废水生化处理的效果。 相似文献
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Biodegradation of keratin waste: Theory and practical aspects 总被引:1,自引:0,他引:1
Keratin-rich by-products, i.e. bristles, horns and hooves, chicken feathers and similar, are a source of nutrients for animals (amino acids) and plants (N, S). Contemporary developments in the management of keratin waste in feeds and fertilizers comply with human and animal health protection regulations and respect the principles of ecological development. Biotechnological methods employing keratinolytic bacteria and microscopic fungi play a key role in processing keratin waste.This study reviews the current knowledge on the ecology and physiology of keratinolytic microorganisms and presents the biodegradation mechanism of native keratin. The structure and chemical composition of keratin proteins are described, and methods of keratin waste biotransformation into products of practical industrial and natural value, especially composts, are discussed. 相似文献
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Exposure to persistent organic pollutants (POPs), such as polychlorinated biphenyls (PCBs), dichlorodiphenyldichloroethane (p,p′-DDE), and hexachlorobenzene (HCB) continues to be of concern due to their ubiquitous distribution and high persistence. Current toxicant body burden is still a primary concern within the Akwesasne Mohawk Nation since other studies conducted within the community have shown relationships between these POPs and endocrine disruption.In this article we describe the levels of these toxicants in young adults of the Akwesasne Mohawk Nation between the ages of 17 and 21 years of age (mean age 18.1 years), and investigate potential influences of their current body burden. Seventeen congeners in fourteen chromatographic peaks were detected in 50% or more of the individuals sampled (geometric mean [GM] of the sum of these congeners = 0.43 ppb). Congeners 118, 138[+163 + 164] and 153 had the highest rate of detection (?98%) within the Akwesasne young adults. Of the other organochlorines, HCB (GM = 0.04 ppb) and p,p′-DDE (GM = 0.38 ppb) were found in 100% and 99% of the sample respectively.Significantly higher levels of PCBs were found among individuals who were breastfed as infants, were first born, or had consumed local fish within the past year. When compared to levels of p,p′-DDE, HCB, and 13 specific congeners reported by the CDC for youth between the ages of 12 and 19 years, the geometric means of several congeners (CBs 99, 105, 110, and 118) among the Akwesasne were higher than the reported CDC 90th percentile. In contrast, levels of CB 28 in Akwesasne young adults were ∼50% or less than those of the CDC cohort. p,p′-DDE and HCB levels were generally higher in the CDC cohort (GM of 0.516 and 0.065 ppb, respectively for Mohawks vs. 2.51 and 0.123, respectively, for CDC). Concentrations of non-persistent PCBs among this sample of Akwesasne young adults were higher than those reported by the CDC suggesting continued exposure, but lower than those associated with severe contamination.Additional research into the concentration trends of individual PCB congeners within Akwesasne youth and young adults is warranted to further improve our insight into the determinants and influences of organochlorine concentrations within members of the Akwesasne community. 相似文献
109.
2,4-Dichlorophenol (2,4-DCP) is known as an important chemical intermediate and an environmental endocrine disruptor. There is no paper dealing with the predicted no-effect concentration (PNEC) of 2,4-DCP, mainly due to shortage of chronic and site-specific toxicity data. In the present study, toxicity data was obtained from the tests using six Chinese native aquatic species. The HC5 (hazardous concentration for 5% of species) was derived based on the constructed species sensitivity distribution (SSD), which was compared with that derived from literature toxicity data of non-native species. For invertebrates, the survival no-observed effect concentrations (NOECs) were 0.05 and 1.00 mg L−1 for Macrobrachium superbum and Corbicula fluminea, respectively. NOECs based on fishes’ growth were 0.10, 0.20 and 0.40 mg L−1 for Mylopharyngodon piceus, Plagiognathops microlepis and Erythroculter ilishaeformis, respectively. For aquatic plant Soirodela polyrhiza, NOEC based on concentration of chlorophyll was 1.00 mg L−1. A final PNEC calculated using the SSD approach with a 50% certainty based on different taxa ranged between 0.008 and 0.045 mg L−1. There is no significant difference between HC5 derived from native and that from non-native taxa. 相似文献
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