污泥龄对LSP & PNR污泥减量新工艺运行效能的影响

通过研究分析污泥龄(SRT)对富磷污水除磷的LSP&PNR污泥减量新工艺运行效果的影响,结果发现,延长污泥龄有利于提高系统的厌氧释磷能力,但不影响其总的除磷率,同时磷的回收比例增大,当SRT=50 d时,磷回收率取得最大值70.4%;LSP&PNR系统污泥龄增加,还有利于污泥产率的降低.试验还发现,排富磷污水除磷的长污泥龄LSP&PNR系统的除磷效率与污泥产率之间不存在制约关系,即系统可以同时获得优异的污泥减量与生物除磷效果,当SRT=50 d时,每降解1 kg COD仅产生0.143 kg污泥,而除磷率达最高值92.8%;LSP&PNR系统中SRT、DO与SVI之间存在一定的相关性,在供氧充足(DO=0.8～1.5 mg/L)条件下,SRT增加,SVI越高,但对于SRT为50 d的LSP&PNR系统,稳定运行时没有污泥膨胀之虞.     

非饱和土石坝渗流分析

传统的渗流分析主要考虑饱和区而忽略非饱和区内的渗流,本文基于饱和-非饱和渗流计算原理,采用有限元法考虑了非饱和区渗流的影响,并以各向同性均质坝和心墙土石坝为算例进行计算分析。算例表明,由于基质吸力产生的虹吸作用,使得浸润线上部的非饱和区内也存在着连续的水流,通过分析这种水流的特点,定性地得出其对土石坝渗流稳定性的影响。     

陕西省2000年天气气候异常变化与自然灾害

分析陕西省2000年天气气候变化发现,隆冬降雪明显增多,春旱异常严重,秋霖明显,沙尘暴天气明显增加,这是多年来未曾见到的现象。异常的天气气候使得多种自然灾害并发。     

城郊土壤共存元素对土壤作物系统Cd、Pb迁移的影响分析——以白银市城郊区为例

通过共存元素对土壤小麦系统Cd、Pb行为影响的调查研究发现：大田条件下共存元素以正对数模式与根系Cd、Pb密切相关,同种元素间相关程度最高;根系Cd、Pb积累主要取决于土壤环境Cd、Pb的含量,共存元素也产生一定的影响,认为要防止重金属通过食物链对人类的危害,就必须降低土壤环境中重金属的总量。     

熟料造纸清洁生产量化评价—以承德兴业造纸项目为例

运用专家调查打分法,以具体的承德兴业造纸项目为例,初步探讨了清滞生产量化评价方法,程序以及清洁生产评价指标的应用。     

Effect of air-drying and oven-drying treatment on Cr(VI) content and Cr bond forms in soil

Air-drying and oven-drying are pretreatment processes often used before testing and analyzing various soil characteristics in the laboratory. This study selected three kinds of soil, including red soil, entisol, and alluvial soil, and examined the variation of the Cr(VI) content and Cr bond forms in these soils during air-drying and oven-drying. The results show that when the soil is air-dried in natural environment, the Cr(VI) content decreases with air-drying time. On day 10 of air-drying, the Cr(VI) content in these soils is 22.8～47.9 % of the initial value. When the soil is oven-dried, the Cr(VI) concentration decays faster; on day 8, the Cr(VI) is no longer detected in these soil samples. When the Cr(VI)-contaminated soil is treated by air-drying and oven-drying, the Cr bond form converts into a more stable form. After oven-drying, the Cr mainly exists in Fe–Mn oxide form, organic bond form, and residual form. The air-drying and oven-drying pretreatment processes of soil reduce the Cr(VI) content and stabilize the Cr bond form. If the laboratory analytic results are applied to risk analysis or remediation strategy planning for chromium-contaminated soil, the toxicity, bioavailability, and mobility of Cr in soil may be underrated.     

Molecular detection and comparison of Acanthamoeba genotypes in different functions of watersheds in Taiwan

The protistan genus Acanthamoeba is a free-living amoeba existing in various environments. Within this protistan genus, there are some species recognized as potential human pathogens, which may cause granulomatous amoebic encephalitis, Acanthamoeba keratitis and chronic granulomatous lesions of the skin. In this study, 211 water samples were collected from two watersheds in southern Taiwan. We detected Acanthamoeba based on the PCR amplification with a genus-specific primer pair and investigation of Acanthamoeba in Puzih River and Kaoping River in southern Taiwan. Acanthamoeba species were detected in 34 (16.1%) samples. The presence or absence of Acanthamoeba within the water samples showed significant difference with the levels of water temperature and total coliforms. The most frequently identified Acanthamoeba genotype was T4 (n = 19), followed by T5 (n = 8), and then T15 (n = 3). Genotype T6, T7/T8, T11 and T12 were all detected once. Genotype T4, T5, T6, T11 and T15 of Acanthamoeba are responsible for Acanthamoeba keratitis and should be considered a potential health threat associated with human activities in environmental surface water watersheds.     

Assessing soil and groundwater contamination in a metropolitan redevelopment project

The purpose of this study was to assess contaminated soil and groundwater for the urban redevelopment of a rapid transit railway and a new mega-shopping area. Contaminated soil and groundwater may interfere with the progress of this project, and residents and shoppers may be exposed to human health risks. The study area has been remediated after application of first remediation technologies. Of the entire area, several sites were still contaminated by waste materials and petroleum. For zinc (Zn) contamination, high Zn concentrations were detected because waste materials were disposed in the entire area. For petroleum contamination, high total petroleum hydrocarbon (TPH) and hydrocarbon degrading microbe concentrations were observed at the depth of 7 m because the underground petroleum storage tank had previously been located at this site. Correlation results suggest that TPH (soil) concentration is still related with TPH (groundwater) concentration. The relationship is taken into account in the Spearman coefficient (α).     

燃煤电厂在线监测系统颗粒物浓度排放系数影响因素的探讨

选取上海市7家未安装气-气换热器的国控燃煤电厂作为研究对象,从煤质、除尘器、脱硫协同脱除作用以及锅炉工况负荷等方面探讨对颗粒物浓度排放系数 K值产生的影响,得出上述因素通过改变脱硫进口颗粒物浓度值影响 K值,当脱硫进口颗粒物浓度较低、波动范围较小时,其 K值也维持相对稳定的状态;当脱硫进口颗粒物浓度较高、波动范围较大时,其 K值也会发生较大的变化等结论。     

Risk assessment of heavy metals in road and soil dusts within PM2.5, PM10 and PM100 fractions in Dongying city, Shandong Province, China

15 road and 14 soil dust samples were collected from an oilfield city, Dongying, from 11/2009-4/2010 and analyzed by inductively coupled plasma-mass spectroscopy (ICP-MS) for V, Cr, Mn, Co, Ni, Cu, Zn, As, Cd and Pb within PM(2.5), PM(10) and PM(100) fractions synchronously. Metal concentrations, sources and human health risk were studied. Results showed that both soil and road dust exhibited higher values for Mn and Zn and lower values for Co and Cd for the three fractions. Mass concentration ratios of PM(2.5)/PM(10) and PM(10)/PM(100) for metals in road and soil dust indicate that most of the heavy metals tend to concentrate in fine particles. Geoaccumulation index and enrichment factors analysis showed that Cu, Zn and Cd exhibited moderate or heavy contamination and significant enrichment, indicating the influence of anthropogenic sources. Vanadium, Cr, Mn and Co were mostly not enriched and were mainly influenced by crustal sources. For Ni, As and Pb, they ranged from not enriched to moderately enriched and were influenced by both crustal materials and anthropogenic sources. The conclusions were confirmed by multivariate analysis methods. Principle component analysis revealed that the major sources were vehicle emission, industrial activities, coal combustion, agricultural activities and crustal materials. The risk assessment results indicated that metal ingestion appeared to be the main exposure route followed by dermal contact. The most likely cause for cancer and other health risks are both the fine particles of soil and road dusts.