给水厂残泥免烧陶粒曝气生物滤池生物负载性能研究

为全面探究给水厂残泥免烧陶粒（UCWTR）作为曝气生物滤池（BAF）优质填料的可行性,本研究以商品粘土陶粒作为参比,考察了BAF系统内UCWTR的生物挂膜及其对污染物去除效能。研究结果表明：与粘土陶粒BAF相比,基于UCWTR填料的BAF(UCWTR-BAF)系统挂膜启动快,挂膜培养5 d后,其对COD、氨氮、总氮的去除率即可稳定达到85%、75%和65%。其中,UCWTR-BAF系统氨氮进水质量浓度为25～50 mg/L,出水质量浓度在5～15mg/L范围内。挂膜培养15 d后,BAF系统内生物相丰富、成熟,UCWTR生物负载量达到0.234 mg/g,显著高于粘土陶粒生物膜负载量（0.160 mg/g）。挂膜前后陶粒SEM对比分析结果显示：对比粘土陶粒,UCWTR表面更加粗糙,孔隙更丰富。以上研究结果表明UCWTR具有较强的生物负载能力,可作为BAF填料应用于污水处理领域。     

Spatial distribution of chromium in soils contaminated by chromium-containing slag

To evaluate the metal chromium (Cr) contamination of soil at a chromium-containing slag site by ferrochromium production, the contaminated sites, under slag heap, in the vicinity of slag heap and arable soils near the outlet of sewer channel, and unpolluted site 5 km away from one ferroalloy plant in Hunan Province, China, were selected. The concentrations of total Cr and water soluble Cr in bulk soil samples and profile depth samples were determined. The results show that the soils in the vicinity of slag heap have the highest total Cr content followed by the soils under the slag heap and near the outlet of sewer channel of the factory. The mean concentrations of total Cr in the top soils at above three contaminated locations exceed the critical level of Secondary Environmental Quality Standard for Soil in China by 3.5, 5.4 and 1.8 times. In most Cr polluted soils, total Cr has a relative accumulation in soil depth of 40-60 cm, but this trend is not found in unpolluted soils. The average concentrations of water soluble Cr (Ⅵ) in top soils under slag heap and in the vicinity of slag heap are 176.9 times and 52.7 times higher than that in the uncontaminated soils, respectively. However, water soluble Cr (Ⅵ) contents in soils near sewer channel are all low and the values are close to that in the uncontaminated soils. Although water soluble Cr (Ⅵ) content in soil profiles decreases with soil depths, it in soils under slag heap maintains a high level even at a depth of 100-150 cm. The results imply that the transportation of Cr (Ⅵ) can result in a potential risk of groundwater system in this area.     

Inhibitory effect of Cr（Ⅵ） on activities of soil enzymes

To evaluate the influence of various Cr(VI) concentrations (0.05, 0.25, 0.50, 1.00 and 2.00 g/kg) on the activity of soil enzymes, the activities of catalase, polyphenol oxidase, dehydrogenase, alkaline phosphatase in soils were investigated in the incubation experiment with a period of 35 d. The results indicate that all the tested Cr(VI) concentrations significantly inhibit dehydrogenase activity by over 70% after 35 d. The activity of alkaline phosphatase is slightly inhibited during the whole experiment except for on the day 7. Cr(VI) has no obvious effect on the activity of catalase in soil. On the contrary, Cr(VI) stimulates the activity of polyphenol oxidase. The results suggest that dehydrogenase activity can be used as an indicator for assessing the severity of chromium pollution. Foundation item: Projects(2006AA06Z374, 2007AA021304) supported by the National High-Tech Research and Development Program of China; Project(2008SK2007) supported by the Key Program of Science and Technology of Hunan Province, China     

硫酸亚铁-PEG-PAM混合絮凝剂处理石煤提钒废水试验研究

将聚乙二醇(PEG)与聚丙烯酰胺(PAM)以一定比例混合溶解,制备PEG-PAM混合絮凝剂;利用硫酸亚铁与PEG-PAM联合处理石煤提钒废水,考察了混合比、Fe2+投加量、絮凝pH对As、V、Cr、Cd去除率及水中Fe余量的影响。结果表明:混合比对各污染物的去除效果影响不大,但影响絮体质量;在较宽的pH和Fe2+投加量范围内,As、V、Cr的去除率较高且较稳定;而Cd和Fe的去除则受pH影响很大,pH越高,去除效果越好。当FeSO4.7H2O投加量为0.270 5 g/L、pH为8.0～8.2、PEG与PAM混合比为50%时,钒冶炼废水中As、V、Cr、Cd的质量浓度分别降低至0.018 4、0.730、0、0.005 6 mg/L,均低于GB 26452-2011所规定的排放限值。Fe的质量浓度降低至0.053 0 mg/L,低于国内废水排放标准限定的2.0 mg/L。     

铬污染土壤修复技术研究进展

随着铬渣治理的深入进行,渣场底部及附近铬污染土壤的修复亦提上日程,铬污染土壤的修复有其特殊性。各种地质条件形成的土壤含铬量相差很大,而土地的用途有很多种,不同的方法治理效果差异很大。文章介绍了铬污染的来源及危害,详述了土壤修复的5种技术,并对5种修复技术进行了评述。     

火电厂事故灰场大气环境防护距离取值合理性探讨

为防止火电厂灰场的扬尘污染,环境影响评价中均会设置大气环境防护距离,在该范围内不允许有常住居民,且土地利用性质也会受到影响.但对事故灰场设置过大的大气环境防护距离对电厂投资、土地资源都是一种浪费.文章以南方典型A火电厂为例,从控制起尘风速、粉煤灰含水率、是否碾压作业等方面,对事故灰场大气环境防护距离取值的合理性进行了分析,结果表明,在采用小块堆灰作业时,设置150m的大气环境防护距离,既能满足灰场场界达标排放的要求,又可防止扬尘对敏感目标的污染影响.     

IPv6物联网接入网关的设计实践

在智能农业大棚物联网系统中,传感器节点采集的数据需通过互联网上传到远程服务器,Contiki节点间使用6LoWPAN,与传统的IPv4不能直连,需配置一个物联网网关. 通过移植OpenWRT系统至HG255D无线路由器,使得该路由器成为一个小巧、实用的嵌入式Linux系统,能够运行开源或自行开发的程序. 本文将介绍如何在HG255D路由器上实现IPv6物联网接入网关设计的过程. 主要涉及OpenWRT固件的编译、路由器配置修改、网关程序的移植,以及效果演示.     

冶炼废渣资源化、无害化工艺研究

本研究针对某冶炼厂的冶炼废渣,利用生物浸出技术浸提废渣中的有价金属,研究并提出冶炼废渣的资源化、无害化及减量化工艺。     

载银硅酸盐玻璃缓蚀阻垢剂的研究进展

我国冷却水用量占工业用水总量的80%以上,如何实现冷却水节水与零排放对推进工业循环发展至关重要。缓蚀阻垢剂可有效解决冷却水系统的结垢腐蚀问题,提高冷却水的循环利用率。其中,载银硅酸盐玻璃缓蚀阻垢剂是一种缓释型不含磷的多功能水处理剂,同时具备抑菌、阻垢和缓蚀功能,且无二次污染问题,应用前景广阔。本研究重点详述了控释型载银硅酸盐玻璃缓蚀阻垢剂主成分功能及制备方法,总结分析了载银硅酸盐玻璃缓蚀阻垢剂研究现状、现存问题与发展趋势。     

DMDAAC复配改性PFSS处理高砷、镉废水的研究

以中高浓度As、Cd废水为处理对象,探讨了二甲基二烯丙基氯化铵(DMDAAC)复配改性聚合硅酸硫酸铁(PFSS)的絮凝性能。PFSS与DMDAAC复配形成稳定的均相复合溶液,当温度为100℃、DMDAAC投加量为200 mL/L、复配时间为5 min时制备的液态复合絮凝剂的絮凝效果最佳。复合絮凝剂在投加量为12.5 mL/L、pH值为8的条件下,能够有效去除废水中的Cd、As,出水中的Cd、As含量满足试验设计要求(Cd≤0.05 mg/L、As≤0.5 mg/L)和《铅、锌工业污染物排放标准》(GB 25466—2010)的要求。FT-IR和SEM检测结果表明,复合絮凝剂是相互融合的复合体系,PFSS改变了DMDAAC所处的化学环境,使其中一些官能团的特征吸收峰发生位移。