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161.
162.
Robert D Stedtfeld Sam Baushke Dieter Tourlousse Benli Chai James R Cole Syed A Hashsham 《Water environment research》2007,79(3):260-269
Genetic markers are expected to provide better specificity in epidemiological studies and potentially serve as better indicators of waterborne pathogens. Methods used to assess genetic markers of emerging microbial indicators include pulsed field gel electrophoresis, polymerase chain reaction (PCR), and microarrays. This paper outlines a high-throughput approach to screen for such genetic markers using a set of theoretical and experimental screening tools. The theoretical screening involves evaluating genes related to the ribosomal RNA and specific functions from emerging indicator groups, followed by experimental validation with appropriate sampling schemes and high-throughput and economical screening methods, such as microarrays, real time PCR, and on-chip PCR. Analysis of a wide range of samples covering temporal variability in location, host, and waterborne disease outbreaks is essential. The proposed approach is expected to shorten the time and cost associated with searching for new genetic markers of emerging indicators by at least 10-fold. 相似文献
163.
Spectroscopic studies of the progress of humification processes in humic substances extracted from refuse in a landfill 总被引:2,自引:0,他引:2
Humic acids (HA) and fulvic acids (FA) extracted from refuse in a landfill at different landfill ages were characterized by elemental composition, GPC, FTIR, and (13)C CP/MAS NMR. The elemental composition analysis revealed high O/C and low H/C ratios in the FA, indicating a high proportion of O-alkyl and carboxylic acids in the FA. The M(w) and M(n) values and M(w)/M(n) ratios indicated that the HA had a higher molecular weight and were more homogeneous with respect to molecular weight. FTIR spectra showed that the FA had relatively more intense bands assigned to aliphatic structures and were abundant in oxygen-containing function groups. The analytical results of (13)C CP/MAS NMR suggested that there were more oxygenated aliphatic carbons and fewer aromatic carbons in the FA than in the HA. All the results demonstrated that the degree of humification increased with landfill age. 相似文献
164.
纤维素乙醇糟液对稻秸猪粪厌氧发酵的促进机制 总被引:1,自引:0,他引:1
纤维乙醇生产会伴随产出大量酸性糟液。利用厌氧技术处理糟液存在C/N低、pH值低等难题,采用糟液与秸秆、猪粪混合后厌氧发酵是一种有效的糟液处理途径。秸秆添加糟液后,TS比例为3%,6%和9%时各组产气量分别为627.8、585.6和443.9 mL·g-1 TS,大幅度高于不添加糟液的秸秆对照组产气量292.5 mL·g-1 TS,且嗜氢产甲烷途径增强,甲烷体积分数从低于60%增至70%以上。猪粪添加糟液在较低TS浓度3%时产气量最高676.7 mL·g-1 TS,秸秆和猪粪按TS 1:1的比例混合时添加糟液的产气效果最佳。秸秆添加糟液的最大VFAs比秸秆对照高2.8~4.7倍,产气延迟增加,从混合型发酵变为典型的丁酸型发酵;猪粪添加糟液后VFAs浓度相对较低,产气启动快,从混合型发酵转变为典型的丙酸型发酵,说明糟液在不同碳源条件下,有着不同的代谢促进途径。糟液与农业废弃物混合厌氧发酵,是一种高效的共发酵体系。糟液在刺激促进秸秆、猪粪产气提升和解除抑制风险的同时,自身也得到高效降解利用。 相似文献
165.
166.
The landfills of fly ash are the problem of all power plants because this disposed fly ash is not used in any work. This research studies the potential of using disposed fly ashes which have disposal time of 6-24 months from the landfill of Mae Moh power plants in Thailand to replace Portland cement type I. Median particle sizes of disposed fly ashes between 55.4 and 99.3 microm were ground to reduce the sizes to about 7.1-8.4 microm. Both original and ground disposed fly ashes were investigated on physical and chemical properties. Compressive strengths of disposed fly ash mortars were determined when Portland cement type I was replaced by disposed fly ashes at the rate of 10%, 20%, and 30% by weight of cementitious material (Portland cement type I and disposed fly ash). The results presented that most particles of original disposed fly ashes were solid and sphere with some irregular shape while those of ground disposed fly ashes were solid and irregular shape. CaO and LOI contents of disposed fly ashes with different disposal times had high variation. The compressive strengths of original disposed fly ash mortars were low but those of ground disposed fly ash mortars at the age of 7 days were higher than 75% of the standard mortar and increased to be higher than 100% after 60 days. From the results, it could be concluded that ground disposed fly ashes were excellent pozzolanic materials and could be used as a partial replacement of cement in concrete, even though they were exposed to the weather for 24 months. 相似文献
167.
JAZ型絮凝剂对活性染料的絮凝效果 总被引:2,自引:0,他引:2
本文介绍了新近开发的JAZ絮凝凝剂地水样中活性艳红K-2BP,活性紫H-2R和活性黑K-BR染料的絮凝效果及PH值和投药比对脱色率的影响。在中性和弱酸性中絮凝效果好。投药比增大脱色率增加。对活性艳红和活性紫,起始浓度增加则达到88.5%脱色率的投药比降低。对三种活性染料配水和活性 染料配水和活性黑染料生产水脱色率均可达到99%,处理液残余色度在20倍以下。 相似文献
168.
常州市位于太湖流域腹地,其生产生活用水均取自长江,目前总制水能力基本能满足用水需求,但供水水源单一,存有较大的安全隐患。建设备用水源,提高城市供水系统安全性是目前常州市亟待解决的重要问题。新孟河是连接长江,南北贯穿全市、输送水量较大的清水通道河流。现拟结合新孟河延伸拓浚工程的实施,将新孟河作为城市应急备用水源。本文在调查备用水源地周边环境概况、地表水环境质量现状、底泥质量现状的基础上,分析了该区域作为备用水源地可能存在的制约因素,并提出了相应对策,为常州市备用水源地建设提供了合理化建议。 相似文献
169.
湿法回收砷碱渣中锑的工艺研究 总被引:3,自引:0,他引:3
本研究先以水浸实现砷碱渣中的砷锑分离,再对水浸渣进行盐酸浸出,得到了可作为工业原料氯化锑溶液。研究结果表明,在液固比为6:1,温度40℃,浸出时间40min的条件下,可使水浸过程中锑的浸出率低于3%,砷的浸出率达到99%;盐酸浸出中,控制酸浓度为1:1,液固比10:1,温度60℃,授出时间30min,能使锑的浸出率达到88%以上。经过水浸和盐酸浸出,锑的直接回收率为85.36%。 相似文献
170.
对建设项目进行环境影响评价分析,对国民经济的健康稳定发展和保护生态自然环境均有重要的作用,但在具体实施过程中,仍然存在不少问题,如工程分析粗糙、报告书质量不高、评价缺乏针对性和实用性等.本文对此进行了分析,并提出相应对策. 相似文献