炼油废水污泥脱水工艺条件的优化

采用化学除油降黏—污泥调理—离心脱水工艺处理某炼油厂废水处理系统的混合污泥,并对工艺条件进行优化。实验结果表明,最佳的工艺条件为：化学除油降黏阶段处理体系的pH=4,反应温度35 ℃,H₂O₂加入量 2 g/L,m（H₂O₂）∶ m（Fe²⁺）=4,反应时间 60 min;污泥调理反应阶段的CaO加入量7.0 g/L;离心脱水阶段在分离因数为1 558时脱水5 min。在此条件下,得到的泥饼的含水率为70.0%~75.0%（w）,含油率小于2%（w）,污泥比阻约为3.0×10⁷ s²/g。     

Fractionation and speciation of arsenic in fresh and combusted coal wastes from Yangquan, northern China

In this study, the content and speciation of arsenic in coal waste and gas condensates from coal waste fires were investigated, respectively, using the digestion and sequential extraction methods. The fresh and fired-coal waste samples were collected from Yangquan, which is one of the major coal production regions in northern China. High-performance liquid chromatography-inductively coupled plasma-mass spectrometry (HPLC-ICP-MS) was used to determine the concentrations of four major arsenic species [As(III), As(V), monomethylarsonic acid (MMA) and dimethylarsenic acid (DMA)] in the extracts, while ICP-MS was used to measure total As content. Arsenic content in the investigated coal wastes and the condensate ranges between 23.3 and 69.3 mg/kg, which are higher than its reported average content in soils. Arsenic in coal waste exists primarily in the residual fraction; this is followed in decreasing order by the organic matter-bound, Fe–Mn oxides-bound, exchangeable, carbonates-bound, and water-soluble fractions. The high content of arsenic in the condensates indicates that combustion or spontaneous combustion is one of the major ways for arsenic release into the environment from coal waste. About 15% of the arsenic in the condensate sample is labile and can release into the environment under leaching processes. The water extractable arsenic (WEA) in the fresh coal waste, fired coal wastes, and the condensate varied between 14.6 and 341 μg/kg, with As(V) as the major species. Furthermore, both MMA and DMA were found in fresh coal wastes, fired coal wastes, and the condensate.     

Hydrogeochemical assessment of carcinogenic and non-carcinogenic health risks of potentially toxic elements in aquifers of the Hindukush ranges,Pakistan: insights from groundwater pollution indexing,GIS-based,and multivariate statistical approaches

Environmental Science and Pollution Research - Globally, potentially toxic elements (PTEs) and bacterial contamination pose health hazards, persistency, and genotoxicity in the groundwater aquifer....     

运城盆地人类活动氟污染的环境效应研究

氟(F)污染是严重影响人类及动植物生长的环境问题之一,而人类活动已经成为新型环境氟污染的来源之一。调查了运城盆地不同类型工农业污染源中氟的浓度水平,并研究了固体工业污染源中氟在淋滤作用下的环境释出行为。结果表明:采集的固体工业污染源样品中总氟含量最高为1 479.9 mg/kg,平均含量为763.21mg/kg,远高于我国土壤氟含量的平均水平;农药和化肥样品中氟含量均较高,最高含量可达1 161.21mg/kg。氟淋滤试验结果显示:化工厂污染源中的氟溶解性较好,氟释出浓度高达11.0mg/L,具有较大的环境氟污染风险;两种碱性电解质淋滤液Na_2CO_3和NaHCO_3均对氟离子(F~-)的释出有较明显的促进作用。其作用机理包括CO_3~(2-)和HCO_3~-对F~-的竞争性解吸附和离子浓度(主要为Na~+)增加对F~-的络合性释出。     

Exposure characteristics of phthalate metabolites among the Zunyi cohort of pregnant women in Southwest China

Environmental Science and Pollution Research - Reported evidence has increasingly indicated that exposure to phthalates can cause adverse pregnancy outcomes. However, phthalate exposure levels...     

运城盆地高砷区地下水-沉积物中砷的地球化学特征研究

山西运城盆地是干旱半干旱地区,是我国典型的高砷高氟地下水污染区。在对运城盆地七级镇高砷地下水分布区地下水和钻孔沉积物开展地球化学特征研究的基础上,分析了地下水中砷的物质来源以及控制高砷地下水形成的地球化学过程。结果表明:研究区沉积物的主要矿物成分为硅酸盐、碳酸盐矿物以及少量铁氧化物和黄铁矿等,沉积物中砷的赋存形态主要为碳酸盐结合态/吸附态和Fe-Mn氧化物结合态,是地下水中砷富集的主要物源;研究区地下水中有机物含量较低,微生物活动较弱,属于典型的氧化性弱碱性高砷地下水,在此环境中沉积物中微量黄铁矿的氧化性溶解成为地下水中砷的主要物源,此外由于碳酸盐和硅酸盐矿物的风化和水解作用使地下水中富集大量HCO~-_3,故地下水水化学类型多为HCO_3-Na型,而地下水的弱碱性环境和较高浓度的HCO~-_3会通过竞争性吸附导致沉积物中吸附态砷的溶解或解吸附,促进了地下水中砷的富集。     

长江口-杭州湾生态环境监测点位优化布设及水质分析

河口海湾位于陆海交错带,受径潮流作用的双重影响,具有物质输运格局复杂、生态环境变化梯度大等特点。生态环境监测点位布设与优化是科学、客观评估河口海湾生态环境状况的前提。采用空间平衡抽样法开展监测点位增设和优化方案研究,将2020年5月上海市海洋环境趋势性监测布设的142个监测点位,增设至200个,并进一步优化至170个,对优化前后的点位数据进行显著性检验、方差分析和空间自相关分析。结果显示:2组数据之间无显著性差异,并且优化后点位的方差和空间自相关值更小,说明空间平衡抽样法适用于河口海湾生态环境监测点位布设和优化,点位布设和优化结果可客观反映河口海湾的生态环境状况。随后,采用泰森多边形法确定了优化所得的170个离散点位的海域代表面积,克服现有空间插值法的缺陷,为河口海湾生态环境总体状况评价提供技术参考。