Algal growth inhibition by river water pollutants in the agricultural area around Lake Biwa, Japan

An ecotoxicological study of river water discharged from the agricultural area around Lake Biwa was performed by using algal bioassays to guide chemical analysis. Water samples were collected once a week, at least, for 1 year starting in April 1997 and continuing until April 1998. The toxicities of the dissolved and particulate-adsorbed extracts of water samples were evaluated by the algal growth inhibition test and concentrations of individual pesticides were determined. Most of the river water that was collected during the periods when pesticides were applied to the paddy fields caused algal growth inhibition. Some extracts were found to contain herbicides (molinate, mefenacet, simetryn, or esprocarb) as major compounds. According to chemical assay and bioassay, simetryn was identified as the most toxic compound that caused algal growth inhibition.     

大连湾挥发性有机污染物挥发速率常数估算

本文采用气－液双膜模型和大连湾水文参数，对大连湾检测出的挥发性有机物的挥发速率常数进行估算。结果表明，三氯乙烯等１４种挥发性有机物在大连湾海域中的挥发速率常数在８．０×１０＾－３ｈ－１－１．４×１０＾－２×＾－１之间，挥发半衰期在５０ｈ＝８０ｈ之间。因此，挥发至大气是这些在机物主要归宿。     

钢铁渣粉对混凝土中钢筋的保护作用

钢渣和矿渣是冶炼钢、铁过程中产生的固体废物.由于其矿物组成与水泥熟料相似,具有水硬胶凝性能,所以被用作混凝土掺合料.钢铁渣粉是钢渣粉和矿渣粉接一定的比例混合而成的.试验表明,钢铁渣粉的使用能够保留钢渣粉和矿渣粉单掺时的优点,弥补单掺时的缺点,对钢筋起到很好的保护作用.     

炼厂罐区排气减排及集中收集设计

在对储罐排气达标治理时,首先需要采用源头减排措施,减少储罐排气量。在此基础上,核算储罐排气量、吸气量及安全承压等,设计合理的储罐氮气保护系统、储罐排气集中收集系统、罐区排气压力控制系统,实现储罐排气密闭收集和罐区安全稳定运行。某炼油厂储运部21台储罐在正常工况时其大呼吸和小呼吸最大吸气量为876m3/h;但当遇暴雨时,罐区瞬时最大吸气量为2760m3/h,以0.6MPa氮气为补氮源,补氮总管管径需设计为DN100;该罐区最大排气量876m3/h,为了满足储罐排气安全输送,排气收集总管管径需设计为DN200。以混合二甲苯储罐为例,核算了储罐的承压压力、呼吸阀工作压力等,设置储罐排气操作压力范围为600~1200Pa、补氮操作压力范围为200~500Pa。     

Interaction between Cu and different types of surface-modified nanoscale zero-valent iron during their transport in porous media

This study investigated the interaction between Cu^2 + and nano zero-valent iron (NZVI) coated with three types of stabilizers (i.e., polyacrylic acid [PAA], Tween-20 and starch) by examining the Cu^2 + uptake, colloidal stability and mobility of surface-modified NZVI (SM-NZVI) in the presence of Cu^2 +. The uptake of Cu^2 + by SM-NZVI and the colloidal stability of the Cu-bearing SM-NZVI were examined in batch tests. The results showed that NZVI coated with different modifiers exhibited different affinities for Cu^2 +, which resulted in varying colloidal stability of different SM-NZVI in the presence of Cu^2 +. The presence of Cu^2 + exerted a slight influence on the aggregation and settling of NZVI modified with PAA or Tween-20. However, the presence of Cu^2 + caused significant aggregation and sedimentation of starch-modified NZVI, which is due to Cu^2 + complexation with the starch molecules coated on the surface of the particles. Column experiments were conducted to investigate the co-transport of Cu^2 + in association with SM-NZVI in water-saturated quartz sand. It was presumed that a physical straining mechanism accounted for the retention of Cu-bearing SM-NZVI in the porous media. Moreover, the enhanced aggregation of SM-NZVI in the presence of Cu^2 + may be contributing to this straining effect.