Scum in Activated Sludge Plants: Impact of Non‐filamentous and Filamentous Bacteria     

H. Lemmer  G. Lind  E. Müller  M. Schade  B. Ziegelmayer 《洁净——土壤、空气、水》2000,28(1):34-40

Excessive scum production is a widespread phenomenon in present activated sludge wastewater treatment. The question how foaming is initiated and stabilized is still unanswered. Hydrophobic wastewater ingredients and surface active material such as synthetic surfactants are discussed among others as major causative agents for scum production. Focusing on biological impacts non‐filamentous bacteria isolated from scum turned out to contribute to flotation by both cell surface hydrophobicity and emulsification activity, depending on the prevailing substrate and milieu conditions. The biological characterization of scum based on microscopic sludge investigation of conspicuous microorganisms resulted in a significant shift of filamentous and non‐filamentous organism populations with Gram‐positive bacteria prevailing in present nutrient removal plants as compared to the situation ten years ago. Their hydrophobic cell surface is supposed to support adherence and stabilization of interfaces and thus promote sludge flotation. In scum six types of filamentous bacteria turned out to be numerous: Microthrix parvicella and nocardioform actinomycetes, both of them being enriched in the scum fraction, moreover Nostocoida limicola and Eikelboom types 0041/0675, 1851, and 0092. Possible interactive mechanisms between non‐filamentous and filamentous scum bacteria and their selection factors are discussed in order to contribute to a better understanding of scum formation and to provide efficient troubleshooting measures.  相似文献   

Behavior of Steroid Hormones and Conjugates During Wastewater Treatment – A Comparison of Three Sewage Treatment Plants     

Michael P. Schlüsener  Kai Bester 《洁净——土壤、空气、水》2008,36(1):25-33

The fate of the steroid hormones 17 β‐estradiol, estrone, estriol, 16 α‐hydroxyestrone, and β‐estradiol 17‐acetate, the hormone‐conjugates β‐estradiol 3‐sulfate and estrone 3‐sulfate, and the oral contraceptives 17 α‐ethinylestradiol and mestranol were studied during wastewater treatment as wastewater treatment plants are the major source contamination of urban surface waters with steroid hormones. The elimination efficiencies of three different concepts of WWTPs, i. e., activated sludge versus trickling filter, were compared over four weeks at different weather conditions. While larger WWTPs operating on activated sludge eliminated hormones more constantly than smaller WWTPs, heavy rainfall events led to a collapse of the elimination efficiency. By using trickling filter techniques for the treatment of wastewater an elimination of the steroid hormones could not be observed. Additionally, mass flows on a per person basis are compared. In the three experiments, which ran continuously for four weeks each, it turned out that the concentrations of ethinylestradiol and mestranol were below 6 ng/L in all samples. The inflow concentrations were 70 to 82 ng/L (estrone), 17 to 44 ng/L (estradiol), 61 to 130 ng/L (hydroxyestrone), 189 to 255 ng/L (estriol), 10 to 17 ng/L (estrone‐3‐sulfate) and about 28 ng/L (estradiol‐3‐ sulfate). While in the activated sludge treatment plants the elimination of estrone was 90 and 50%, respectively, estrone was formed from precursors in the trickling filter plant. A similar situation occurred for 17β‐estradiol, estrone 3‐sulfate, and estradiol 3‐sulfate. Hydroxyestrone was eliminated with similar efficiencies in all wastewater treatment plants (64 to 82%), as well as estriol (34 to 69%). Accordingly, the emissions of the wastewater treatment plants differed largely and were not attributed to the size of the respective plant, only.  相似文献   

山西省某大型滑坡体治理工程分析及项目管控探讨     

刘伍  马银仁  刘兴龙  张荣幸  李向虎 《城市地质》2013,(4):23-28

本滑坡体为一大型多滑面复合型复活老滑坡,笔者作为本工程的地灾监理,对该滑坡的治理方案进行了全面、深入解读及分析,发现本治理工程在项目整体管控上存在一定问题,这种问题在国内目前的地灾治理工作上具有代表性,分析、探讨本工程在整体项目管控方面的问题具有非常现实的意义,对地灾治理行业管理有一定借鉴作用。  相似文献   

Pre‐treatment of Waste Foundry Sand Via Solidification/Stabilization     

Hatice Merve Basar  Nuran Deveci Aksoy 《洁净——土壤、空气、水》2013,41(1):94-101

This study was performed to propose a suitable treatment for waste foundry sand (WFS) before persistent disposal. It was observed that solidification/stabilization (S/S), which is the common pre‐treatment method because of its comparatively easy and inexpensive applicability, can treat WFS including dissolved organic carbon (DOC) above hazardous landfilling limits. Regular sand was partially replaced with WFS with a ratio of 0–90 wt% in order to prepare three different kinds of mortar samples, where Portland limestone cement (PLC) alone, calcium lime (CL) alone, and PLC together with CL were contained as binders. Leaching behaviors of all S/S products were analyzed according to the TS EN 12457‐4 leaching test. The treatment efficiency was assessed to reduce the DOC content to the levels under the European landfill acceptance criteria. Furthermore, heavy metals (Ni, Zn, Cr), fluoride (F^?), total dissolved solids leachability, and total organic carbon content were analyzed in order to investigate the pre‐treatment ability and to determine whether S/S products can be disposed of in a landfill site with municipal wastes or in a separate landfill site. The results showed that S/S of WFS is an efficient pre‐treatment technique before its disposal in a landfill and provides economical advantages compared to hazardous waste landfilling.  相似文献   

Biodegradability Assessment and Treatability of High Strength Complex Industrial Park Wastewater     

Ahmet Baban 《洁净——土壤、空气、水》2013,41(10):976-983

Industrial park wastewater (IPWW) includes complex non‐biodegradable organic compounds. A wastewater treatability study using biodegradability assessment approach was carried out for an industrial park housing mainly textile and machinery sectors. Biodegradable and inert chemical oxygen demand (COD) fractions with soluble and particulate counterparts were experimentally estimated by implementing respirometric methods. Aerobic batch test methods and oxygen uptake rate profiles were used to map kinetic parameters and COD fractions. Denitrification potential was also determined by application of anoxic batch tests. Relevant kinetic constants, stoichiometric, and design parameters were determined for biological processes. Tests were carried out for raw and physico‐chemically pre‐treated IPWW. Hence, it was aimed to assess the effects and necessity of pre‐treatment on biological processes. Biological mineralization, nitrification, and denitrification processes were also designed and tested using a bench scale continuous treatment model for pre‐treated IPWW. The sum of initial inert soluble COD fraction and production of soluble microbial products decreased about 25% for the case of pre‐treated IPWW as compared to raw IPWW. Eighty‐three percent total COD and 89% total Kjeldahl nitrogen removal efficiencies were attained for the modeling experiments of pre‐treated IPWW. Results showed the significance of pre‐treatment if complex strength industrial wastewaters are to be biologically treated.  相似文献   

云南新平药用蛇纹石矿物学及医疗机理分析     

石能学  李旭俊  段永莉 《云南地质》2011,30(1):89-91

新平蛇纹石是近年才开发的矿物药,因其具有特殊TO型三八面体层状结构及5类活性基因,而能吸附、过滤、分解氟化合物,成为预防、治疗地氟病的重要药源。  相似文献   

O3处理时间与粗饲料纤维性物质成分变化关系的研究     

胡民强  黄冠庆  王润莲  黄晓亮 《广东海洋大学学报》2002,22(1):40-44

将稻秆、麦秆、棉秆 3种粗饲料切成 4cm长 ,水分含量调节到 3 0 % ,用臭氧 (O3)处理 3 0 ,60和90min ,对照组不进行O3处理 ,以比较O3处理对 3种粗饲料纤维性物质成分变化的影响。结果表明 :O3处理能显著降低粗饲料纤维性物质成分含量 ,处理的时间越长 ,降低越多 ,60min前的降幅大于 60min以后的降幅。ADL含量高的粗饲料 ,经O3处理后降幅大。O3处理粗饲料 ,能降低纤维性物质成分含量 ,改善粗饲料的品质 ,提高其利用率  相似文献   

UASB/接触氧化工艺处理玉米淀粉废水研究   总被引：3，自引：0，他引：3       下载免费PDF全文

李艳春 《气象与环境学报》2009,25(1):68-71

针对锦州某玉米深加工企业采用UASB/生物接触氧化方法处理玉米淀粉生产废水,研究主要对UASB反应器启动、运行以及颗粒污泥的结构特性进行实践与探讨。结果表明：UASB反应器经过启动阶段、负荷提高阶段以及稳定运行阶段后,可实现进水量为4513 m3•d-1,进水CODCr平均浓度为7867 mg•L-1,反应器CODCr负荷为7.3 kg•m-3•d-1,出水CODCr浓度为480 mg•L-1,去除率为94%,运行稳定。  相似文献   

Research review on the treatment of urban landscape lakes          下载免费PDF全文

LI Yue-peng  LIU Hai-yan  WANG Li-li 《地下水科学与工程》2017,5(2):152-161

This paper summarizes the treatment experience of eutrophication by domestic and foreign scholars. At the same time, it summarizes the basic methods to govern lakes; Based on this, we advance the basic principles of urban landscape lakes: At first, we must fully investigate lake pollution source, evaluate its pollution ecological risk; Secondly we should put forward possible measures and choose the scheme for implementation, and finally complete the real-time dynamic monitoring, establish long-term supporting policies and treatment mechanism, to ensure that the pollution of lake continues to develop in the direction of health.  相似文献   

Multiple-occurrence regional landslide events in New Zealand: Hazard management issues   总被引：4，自引：2，他引：4  

M. J. Crozier 《Landslides》2005,2(4):247-256

Landsliding in New Zealand most commonly occurs in the form of multiple-occurrence landslide events, simultaneously involving thousands to ten thousands of landslides over areas extending up to 20,000 km². The scale of these events, together with their multiple-hazard character, provide a unique set of management issues that stretch the capabilities of available emergency management services. Several measures for characterising the magnitude and impact potential of these events are presented and compared. While the median density of landsliding is approximately 30 landslides/km², over 100 landslides/km² have been recorded in some events. Specific soil displacement volumes vary widely between events—New Zealand events yield a median value of approximately 140 m³/ha. Measured Ratios of runout length to scar length are commonly about 3:1. However, comparison between events is constrained by lack of standardisation in methods of measurement and recording. Agricultural production loss, damage to road and rail infrastructure and increased flooding are the main consequences of these events. Treatment options involve loss sharing, resource management legislation, and various forms of bio-engineering.  相似文献