Impacts of climate variability and changes on domestic water use in the Yellow River Basin of China

We present a methodology for using a domestic water use time series that were obtained from Yellow River Conservancy Commission, together with the climatic records from the National Climate Center of China to evaluate the effects of climate variability on water use in the Yellow River Basin. A suit of seven Global Circulation Models (GCMs) were adopted to anticipate future climate patterns in the Yellow River. The historical records showed evidences of rises in temperature and subsequent rises in domestic water demand in the basin. For Upstream of Longyangxia region, the impact was the least, with only 0.0021?×?10⁸ m³ for a temperature increase of 1 °C; while for Longyangxia-Lanzhou region, domestic water use was found to increase to 0.18?×?10⁸ m³ when temperature increases 1 °C. Downstream of Huayuankou was the region with the most changes in temperature that gave the highest increase of 1.95?×?10⁸ m³ in domestic water demand for 1 °C of change of temperature. Downstream of Huayuankou was identified as the most vulnerable area, where domestic water demand increases nearly by 42.2 % with 1 °C increase of temperature. Judging from the trends of temperature range, we concluded that future temperature in Yellow River Basin has an increasing tendency. This could worsen the existing issues of domestic water demand and even more to trigger high competition among different water-using sectors.     

Polycyclic aromatic hydrocarbons in surface sediments from drinking water sources of Taihu Lake, China: sources, partitioning and toxicological risk

Sources, partitioning and toxicological risk of 15 priority polycyclic aromatic hydrocarbons (PAHs) in surface sediments from drinking water sources of Taihu Lake, with an area of 2428 km(2) located in the most developed and populated area of China, were studied, and the results were compared with those in other lakes of China and the USA. Concentrations of the 15 PAHs in sediments ranged from 436.6 to 1334.9 ng g(-1) (dw). Gasoline combustion, coal combustion, diesel combustion from shipping and spillage of petroleum were apportioned to be the main sources of PAHs in this area by principal component analysis, which contributed 35.19%, 26.43%, 25.41% and 12.97% to the PAH sources estimated by further multiple linear regression. Levels of PAHs in sediments were negatively correlated with contents of clay and fine silt (<16 μm), while positively with contents of medium silt, coarse silt and sand (>16 μm). Humin with size larger than 16 μm contained the largest part of the burden of PAHs in sediments, but the specific partitioning domain (bound humic acid, lipid or insoluble residue) depended on properties of organic matter reflected by optical absorbance at 465 and 665 nm. Total toxic benzo[a]pyrene equivalent (TEQ(carc)) of the carcinogenic PAHs in sediments varied from 31.8 to 209.3 ngTEQ(carc) g(-1). Benzo[a]pyrene and dibenzo[a,h]anthracene contributed 45.36 and 25.31% to total TEQ(carc), posing high toxicological risk to this area.     

环氧化PVA载体固定漆酶的最佳工艺条件研究

在T=35℃,HAc-NaAc缓冲溶液pH为4的条件下,用环氧化PVA载体对漆酶进行固定化,固定后酶活为游离酶活的95%。用该固定化漆酶处理制浆造纸废水,反复使用6次后,酶活仍保持为初始酶活的45%,且每次COD去除率在40%以上,处理后的废水BOD增大了50%,废水可生化性得到很大提高。     

某海洋平台上海水篮式过滤器事故分析

目的研究分析东海某一海上平台海水用篮式过滤器发生的腐蚀和堵塞事故原因。方法从海洋平台海水系统用篮式过滤器的原理、工艺流程、材料选择、滤网精度,滤芯设计、人工操作等多方面进行分析。结果受内压滤芯结构要优于受外压滤芯结构,如果过滤精度选择过高,会增加压差,造成滤芯堵塞。结论篮式过滤器滤芯单元应采用多滤芯的受内压结构,过滤精度应根据下游用户要求来确定。     

珠三角典型区域农田小区尺度氮、磷、镉、砷输移特征与控制对策

区域氮、磷、镉、砷输移变化是影响农业生产、导致农田面源污染的主要因素。基于土壤表观平衡模型,以珠三角流域佛山市农业科学研究所试验农田为典型研究区域,构建农田小区尺度土壤表观氮、磷、镉、砷平衡模型,对4种元素在土壤中输移结构和平衡进行分析。结果表明：研究区域4种元素的主要输入途径是施肥,而输出的主要形式各有不同。其中,氮、磷主要输出形式是作物富集输出,输出占比分别为57.5%和39.0%;镉、砷主要输出形式分别是地表径流和作物富集输出,输出占比分别为66.7%和10.7%。研究区域4种元素均出现了不同程度土壤富集现象,农田小区尺度氮、磷平衡处于盈余状态,而镉、砷平衡处于亏损状态,4种元素的平衡强度分别为37.40、8.88、−1.35和−20.50 kg/(hm²·a),仅氮、磷未超过当地土壤环境安全阈值。分析试验农田中5类蔬菜各部位镉、砷富集情况发现,砷的富集系数均达到70.0%以上,而镉的富集只在辣椒叶中较为突出,富集系数达到57.5%。研究显示,应重视肥料输入的有效利用,加强农田灌溉水、农作物和地表径流中重金属的监测,以保障区域粮食安全和水环境安全。

     

本溪市区环境空气质量现状及变化趋势

对本溪市的环境空气质量进行了监测分析，结果表明：本溪市环境空气中TSP超过国家环境空气质量二级标准，SO2、NOx、CO、降尘均符合二级标准。其中TSP、SO2、CO、降尘呈下降趋势，NOx变化不明显。     

辽河保护区植被覆盖度时空动态变化及驱动因素

基于500 m分辨率MODIS NDVI数据和Landsat TM/OLI影像构建了辽河保护区2000—2018年的30 m植被覆盖度(fractional vegetation coverage,FVC)数据集,分析了辽河保护区划定前(2000—2009年)和划定后(2011—2018年)植被覆盖时空动态变化及其驱动因素。结果表明:2000—2018年,辽河保护区植被覆盖度整体呈微弱的增加趋势,2000—2009年植被覆盖度呈增加趋势,斜率为0.67%/a,而2011—2018年植被覆盖度呈波动下降趋势,斜率为-0.27%/a,植被覆盖度降低区域主要分布在地势较低洼的河道两侧;相对于2010年,辽河保护区植被在2012—2014年呈轻微的恢复趋势,但2015—2018年又出现了退化趋势。对比植被覆盖度的模拟值和实际值发现,2011—2018年人类活动对植被覆盖度的贡献率增至1.12%,其中2014年人类活动对植被恢复的作用明显。总体而言,辽河保护区划定以来,植被覆盖度呈先上升后下降趋势,主要是由于气候变化引起的;人类活动对植被恢复的作用为正向,植被恢复中人类活动贡献率高达8.42%。     

安全文化的激励机制在企业中的应用

通过行为模型,分析了企业中安全管理者与职工心态对立的原因,认为目前管理者奖罚手段运用失衡是产生这种局面的重要原因。从安全文化的角度提出了相应对策。     

Transparent exopolymer particles (TEPs)-associated protobiofilm: A neglected contributor to biofouling during membrane filtration

• Bacteria could easily and quickly attached onto TEP to form protobiofilms. • TEP-protobiofilm facilitate the transport of bacteria to membrane surface. • More significant flux decline was observed in the presence of TEP-protobiofilms. • Membrane fouling shows higher sensitivity to protobiofilm not to bacteria level. Transparent exopolymer particles (TEPs) are a class of transparent gel-like polysaccharides, which have been widely detected in almost every kind of feed water to membrane systems, including freshwater, seawater and wastewater. Although TEP have been thought to be related to the membrane fouling, little information is currently available for their influential mechanisms and the pertinence to biofouling development. The present study, thus, aims to explore the impact of TEPs on biofouling development during ultrafiltration. TEP samples were inoculated with bacteria for several hours before filtration and the formation of “protobiofilm” (pre-colonized TEP by bacteria) was examined and its influence on biofouling was determined. It was observed that the bacteria can easily and quickly attach onto TEPs and form protobiofilms. Ultrafiltration experiments further revealed that TEP-protobiofilms served as carriers which facilitated and accelerated transport of bacteria to membrane surface, leading to rapid development of biofouling on the ultrafiltration membrane surfaces. Moreover, compared to the feed water containing independent bacteria and TEPs, more flux decline was observed with TEP-protobiofilms. Consequently, it appeared from this study that TEP-protobiofilms play a vital role in the development of membrane biofouling, but unfortunately, this phenomenon has been often overlooked in the literature. Obviously, these findings in turn may also challenge the current understanding of organic fouling and biofouling as membrane fouling caused by TEP-protobiofilm is a combination of both. It is expected that this study might promote further research in general membrane fouling mechanisms and the development of an effective mitigation strategy.