排序方式: 共有93条查询结果,搜索用时 15 毫秒
81.
82.
水质监测是开展水生态环境评价、监管的基础性工作之一。随着对水生态环境保护与管理要求的提高,人工水质监测与自动水质监测相结合的模式应用越来越普遍。以船舶为载体的水质自动监测系统开展巡测,可实现高密度样品采集、检测及信息的实时传输,在长江泸州以下干流水域的实践中取得了良好效果。系统的应用可弥补常规监测断面间距过大、人工监测频次低、固定站房式水质自动监测站近岸取样等不足,对人工监测和自动监测形成有效补充;船载水质自动监测系统能够实现定点、定深、定时监测,可以在河流污染带监测、入河排污行为的监管以及偷排行为的溯源、水污染应急动态监测等工作中发挥有效作用,既可应用于长江干流等河道较宽且水质可能存在岸别差异的河流,也可应用于滇池、太湖、丹江口等大型湖泊、水库水生态环境监管。 相似文献
83.
84.
Caihong Xu Jianmin Chen Zhikai Wang Hui Chen Hao Feng Lujun Wang Yuning Xie Zhenzhen Wang Xingnan Ye Haidong Kan Zhuohui Zhao Abdelwahid Mellouki 《Frontiers of Environmental Science & Engineering》2021,15(3):37
85.
改性斜发沸石处理高浓度氨氮废水 总被引:2,自引:0,他引:2
采用NaOH碱熔法对缙云斜发沸石进行处理,采用正交实验对碱熔法改性沸石的最佳条件进行了选择;并对改性前后的沸石进行粉末X射线衍射(XRD)、电感耦合等离子体发射光谱法(ICP-AES)和扫描电镜(SEM)表征;详细研究了所得改性沸石在氨氮废水处理中的净化性能.结果表明,处理沸石的水热温度对氨氮去除效果的影响最显著;碱熔法处理可使缙云斜发沸石转变为低硅铝比的Na-P型分子筛,它对氨氮废水的NH4+-N具有优异的吸附性能.当改性沸石投加量为5 g,对100 mL浓度为1000 mg.L-1氨氮溶液,氨氮去除率可达77.8%,改性沸石吸附NH4+-N是一快速吸附过程,且能较好地符合Langmuir吸附等温模式,偏向于单分子层的吸附. 相似文献
86.
以陕西花园土为供试土样,采用室内模拟实验,在土壤中加入一定量的聚丁二酸丁二醇酯(PBS),研究不同数均相对分子质量的PBS(Mn分别为3.46×103、8.13×103、1.60×104、3.50×104)对土壤呼吸强度,微生物(细菌(bacteria)、真菌(fungi)、放线菌(actinomycetes))数量的影响,以此来探讨PBS降解产物对土壤微生物生理特性的影响。研究结果表明:①相对分子质量为3.46×103和8.13×103的PBS在其质量分数较低时有利于土壤呼吸强度的增加,有利于细菌的生长,最大增长幅度达到40%,在其质量分数较高时有利于真菌生长,最大增长幅度达到500%。②相对分子质量为1.60×104和3.00×104的PBS随着PBS质量分数的升高,对土壤呼吸强度和微生物数量的促进作用相应增加,对土壤呼吸强度的提高幅度最大达11.6%,对真菌的提高幅度达178%。 相似文献
87.
神经网络模型用于数值水质模型逼近的适用性及非敏感参数的欺骗效应 总被引:7,自引:2,他引:5
水质模型被广泛应用于水环境管理和决策,但却面临着计算时间和模型应用效率等多方面的问题;利用函数映射和逼近等方法来建立水质模型的输入-输出响应关系,可有效减少计算成本并显著改善模型效率.水质模型的输入-输出响应函数关系有多种形式,本文以其中的2种为例,并分别基于2个水质模型(零维总磷模型、WASP/EUTRO5)的案例,分析和验证了神经网络模型在响应关系逼近中的适用性.案例的结果表明:神经网络函数可以有效地用于水质模型输入-输出响应关系的逼近;当网络规模超出阈值大小时,神经网络函数逼近的准确度和泛化度对网络规模不敏感.在案例研究的基础上,推导和讨论了在神经网络模型函数映射过程中所可能出现的非敏感参数的欺骗效应,以及可能由此导致的过度预测或过低预测问题;并建议在神经网络函数逼近中,应只包含水质模型的敏感参数,以防止降低神经网络模型的准确度. 相似文献
88.
Effects of humic acid on residual Al control in drinking water treatment plants with orthophosphate addition 总被引:2,自引:0,他引:2
Wendong WANG Hua LI Zhenzhen DING Xiaochang WANG Rui LIU 《Frontiers of Environmental Science & Engineering》2012,6(4):470-476
This study aimed to investigate the effects of humic acid (HA) on residual Al control in drinking water facilities that used orthophosphate addition. The results showed that adding orthophosphate was an effective method for residual Al control for the raw water without HA. When orthophosphate was added at 1.0 min before the addition of poly aluminum chloride (PACl), the concentrations of soluble aluminum (Sol-Al) and total aluminum (Tot-Al) residue were 0.08 and 0.086 mg·L-1, respectively; both were reduced by 46% compared with the control experiment. The presence of HA would notably increase the residual Al concentration. For the raw water with 5 mg·L-1 of HA, the concentrations of Sol-Al and Tot-Al increased from 0.136 and 0.174 mg·L-1 to 0.172 and 0.272 mg·L-1, respectively. For water with a HA concentration above 5 mg·L-1, orthophosphate was ineffective in the control of residual Al, though there were still parts of orthophosphate were removed in coagulation. The amounts of Al removal were positively correlated with the solids freshly formed in coagulation. Similar to the raw water without HA, the best Al control was obtained with orthophosphate salt added at 1.0 min before PACl. HA concentrations in the raw water, solution pH, and the orthophosphate dosage suitable for residual Al control by orthophosphate precipitation were also investigated. 相似文献
89.
Zhongxian Song Ping Ning Qiulin Zhang Hao Li Jinhui Zhang Yancai Wang Xin Liu Zhenzhen Huang 《环境科学学报(英文版)》2016,28(4):168-177
A series of CeO_2–ZrO_2–WO_3(CZW)catalysts prepared by a hydrothermal synthesis method showed excellent catalytic activity for selective catalytic reduction(SCR)of NO with NH_3 over a wide temperature of 150–550°C.The effect of hydrothermal treatment of CZW catalysts on SCR activity was investigated in the presence of 10% H_2O.The fresh catalyst showed above 90% NO_x conversion at 201–459°C,which is applicable to diesel exhaust NO_x purification(200–440°C).The SCR activity results indicated that hydrothermal aging decreased the SCR activity of CZW at low temperatures(below 300°C),while the activity was notably enhanced at high temperature(above 450°C).The aged CZW catalyst(hydrothermal aging at 700°C for 8 hr)showed almost 80% NO_x conversion at 229–550°C,while the V_2O_5–WO_3/TiO_2 catalyst presented above 80% NO_x conversion at 308–370°C.The effect of structural changes,acidity,and redox properties of CZW on the SCR activity was investigated.The results indicated that the excellent hydrothermal stability of CZW was mainly due to the CeO_2–ZrO_2 solid solution,amorphous WO_3 phase and optimal acidity.In addition,the formation of WO_3 clusters increased in size as the hydrothermal aging temperature increased,resulting in the collapse of structure,which could further affect the acidity and redox properties. 相似文献
90.
焚烧飞灰水泥固化技术研究 总被引:26,自引:1,他引:26
对利用水泥固化技术处理城市垃圾焚烧飞灰的效果进行了实验研究,分析了焚烧飞灰的主要化学组成,考察了水洗预处理对飞灰组成及固化效果的影响,研究了不同水泥/飞灰配比下所制得固化块的机械性能和重金属浸出毒性结果表明,焚烧飞灰主要元素包括Cl、Ca、O、K、S、Na等,此外还含有一定量的重金属包括Zn、Pb、Cu、Cd和Cr等.经过水洗预处理,焚烧飞灰中的可溶性盐类大大减少,飞灰固化块的强度得到了一定的提高,重金属浸出毒性则有明显的降低,预处理飞灰所制固化试块在养护28d后其重金属浸出毒性都能达到相应的控制标准,其中重金属Pb浸出浓度比原灰所制固化块降低了11%(飞灰添加量20%)~59%(飞灰添加量80%);随着水泥添加量的增加,飞灰固化块的抗压强度也随之提高.添加60%水泥的固化块在养护28d时的抗压强度最高,达425 N·cm-2;预处理飞灰固化块有着较强的抵御环境变化能力,重金属浸出毒性在pH值1~13的范围内都比较稳定. 相似文献