沉积物中邻苯二甲酸酯类物质的分析方法及污染特征研究进展

综述了近年来国内外有关河湖沉积物中邻苯二甲酸酯类物质(PAEs)的分析方法和污染特征研究进展。详细阐述了索氏提取法、超声提取法、微波辅助萃取法、加速溶剂萃取法及被动采样技术等沉积物PAEs前处理方法,柱层析法、固相萃取法2种净化方法和气相色谱、气相色谱-质谱、气相色谱-三重四极杆质谱、高效液相色谱等仪器分析方法,并对比分析了上述方法的优缺点,以期为更高效提取河湖沉积物中PAEs提供参考依据;同时总结了近年来国内外河湖沉积物中PAEs污染特征的研究进展,相比欧美等发达国家,我国沉积物PAEs污染较严重,潜在生态风险较高,主要污染物为DBP和DEHP等。     

二级MBBR处理城市污水高品质水再生过程产生的反渗透浓水填料最佳填充率研究

针对城市污水处理厂尾水生产高品质再生水过程中产生的反渗透浓水N H 4 + -N浓度高、盐度高等特点,采用亚硝化-反硝化二级移动床生物膜反应器(二级MBBR)中试装置进行深度脱氮,比较填料填充率(filling ratio,FR)分别为51%、42%和32%情况下,二级MBBR对N H 4 + -N、N O 3 - -N和CODCr等污染物的去除效果。结果表明:亚硝化MBBR中填料FR分别为51%、42%和32%时,N H 4 + -N平均去除率分别为67.0%±4.0%、71.3%±8.9%和73.2%±6.1%,FR优选32%;反硝化MBBR填料FR分别为51%、42%和32%时,N O 3 - -N平均去除率分别为73.1%±4.2%、63.7%±9.4%和64.9%±10.4%。考虑到经济性,优选填料FR为32%。     

响应面法分析Fenton氧化处理采油废水的过程

采用Fenton氧化对采油废水进行研究,选取双氧水与二价铁离子的摩尔比、初始pH值和反应时间为自变量,以废水的COD去除率为响应值,通过Box-Behnken设计方法进行实验设计,进行了3因素3水平共15个实验点的实验。使用响应面分析法对实验结果进行模拟及分析,建立了响应值与3个自变量的二次多项式方程模型。Fenton氧化的优化工艺条件:n(H2O2):n(Fe2+)=0.8,pH=3.0以及反应时间60 min。在该优化条件下,废水的COD去除率可达72.8%,经实验验证,实际值与模型预测值拟合性好,偏差仅为0.5%。实验结果证实了该模型分析采油废水处理运行参数的准确性。优化工艺后的处理水质COD值完全满足油田废水达标排放的要求。通过总离子色谱图和质谱检索分析原油中的成分变化情况,证实Fenton方法对原油组分的降解效果。     

Uncovering the evolution of tin use in the United States and its implications

• US tin use decreases as the GDP value added by manufacturing sector increases. • Global and China’s tin use increases as the GDP added by manufacturing increases. • A sigmoid curve can fit the US tin use data well. • US tin use patterns is not due to the finite tin reserves or resources. • Policies, substitutions, etc. play key roles in the changing tin use patterns. Tin is of key importance to daily life and national security; it is considered an essential industrial metal. The United States (US) is the world’s largest economy and consumer of natural resources. Therefore, the analysis of historical tin use in the US is helpful for understanding future tin use trends in the world as a whole and in developing countries. Time series analysis, regression analysis with GDP or GDP/capita, and historical data fitted with logistic and Gompertz models are employed in this study. Historical tin use in the US shows three stages—increase-constant-decrease, as GDP per capita has increased. Tin use in the US is negatively correlated with the GDP value added by the manufacturing sector, while the use of tin worldwide and in China continues to increase along with the GDP value added by the manufacturing sector. Although a sigmoid curve can fit the US tin use data well, that use is not directly related to the limited tin reserves or resources. Rather, policies, economic restructuring, substitutions, new end-use markets, etc. have played key roles in the changing tin use patterns. This work contributes to understanding future tin use at both the global and national levels: tin use will continue to increase with GDP at the global level, but use patterns of tin at the national level can be changed through human intervention.     

氨氮浓度对马铃薯加工废水厌氧消化的影响

为考察氨氮浓度对中温厌氧消化处理马铃薯加工废水的影响,通过批式实验,探究该类废水厌氧消化处理的氨氮抑制阈值。结果表明：氨氮浓度为3 000 mg·L⁻¹ (TAN≈3 659 mg·L⁻¹)时,累积产甲烷量降低至276.1 mL·g⁻¹且出现产甲烷迟滞期;氨氮浓度为4 000 mg·L⁻¹ (TAN≈4 468 mg·L⁻¹)时,累积产甲烷量仅为对照组的39.2%,迟滞期明显延长了7.2 d;高浓度氨氮抑制造成了以丙酸为主的VFAs积累和有机物(蛋白质等)降解不完全,这是COD去除率下降的主要原因;VFAs作为氨氮抑制发生时COD的主要组分,其积累可作为马铃薯加工废水厌氧消化过程发生氨氮抑制的指示因子;马铃薯加工废水中温厌氧消化的氨氮阈值约为3 000 mg·L⁻¹。该结果可为马铃薯加工废水的高效处理与资源化利用提供参考。     

两段进水生物膜法OOA-MBR工艺强化生物脱氮

开发出一种两段进水生物膜法好氧/好氧/缺氧-膜生物反应器（OOA-MBR）强化生物脱氮工艺,以模拟生活污水为研究对象,重点考察了流量分配比、曝气方式和水力负荷等因素对系统运行效果的影响,并对工艺控制参数进行了优化。实验结果表明,在系统HRT 4.8 h,流量分配比为1：1,后置MBR池曝气方式采取Air-on 4 min/Air-off 6 min模式,进水COD（380±20）mg·L-1、NH4+-N（35±5）mg·L-1、TN（35±5）mg·L-1时,出水COD、NH4+-N和TN去除率分别达到93.9%、91.8%和77.7%,出水水质满足《城镇污水处理厂污染物排放标准》（GB 18918-2002）一级A标准。     

寒地芦笋的高产栽培技术

本文通过对芦笋的高产栽培技术与开发利用研究，提出黑龙江省可扩大芦笋的种植面积，形成开发利用规模，为发展乡镇企业开创一条致富门路，并满足黑龙江市场需求。     

河冰对桥墩作用的冰荷载计算方法(Ⅰ)——河冰的力学性能试验

通过对松花江河冰的物理力学性能试验和松花江公路大桥桥墩的流冰动压力测量、桥面的脉动测量 ,依据国内外对冰 -结构相互作用的分析 ,提出了适合我国黑龙江冰情特点的春季流冰冰荷载的计算方法。     

浅谈实施教师资格制度

实施教师资格制度使教师的任用走上了科学化、规范化、法制化的轨道,推动了教育人事的改革,逐步形成了开放式的教师培养体系。     

Spatial and temporal modeling of microbial contaminants on grazing farmlands

This paper introduces an integrated spatial and temporal modeling system developed mathematically for assessing microbial contaminants on animal-grazed farmlands. The model uses fecal coliform, specifically Escherichia coli, as an indicator of fecal contamination and describes the sources, sinks, transport processes, and fate of E. coli contaminants in catchments and associated streams. Spatial features include grazing location, land topography, distance to a nearby stream, and distance through the stream network to the outlet. Temporal features are population dynamics on the land surface, in flow, and on streambeds. The model applies the principles of conservation of mass balance on two different types of pools: grid cells on land surfaces and networked stream segments. The model aims to improve the prediction of the effects of different land management strategies on the fecal contamination of waterways. This is achieved by characterizing the movement of fecal contaminants from land to streams and in-stream mobilization. Processes of attenuation, diffusion, and transport govern the movement. Our study site is a hill land catchment with an area of 140 ha and is used exclusively for animal grazing. The model was calibrated with previous research results, and then tested using the data collected at the outlet of the catchment. The sensitivity of the model predictions was analyzed for different scenarios: effect of stock rate, attenuation rate, and flow volumes. The similar pattern between monitored and predicted E. coli concentration proved that the model captures the key features that control the population dynamics of fecal contaminants. Further experiments are required to expand the model's functionality for covering more mitigation options.