基于TROPOMI的扬州市对流层甲醛和二氧化氮时空分布特征分析

以2020年1月—2021年9月对流层观测仪（TROPOMI）卫星观测资料反演获取的对流层甲醛（HCHO）、二氧化氮（NO₂）柱浓度数据为依据,采用统计方法分析了扬州市HCHO和NO₂柱浓度的时空分布特征。结果表明,扬州市对流层HCHO、NO₂平均柱浓度分别为903.01×10¹³, 633.77×10¹³mole/cm²;受太阳紫外辐射影响,HCHO柱浓度变化特征表现为6月最高、1月最低;受气象条件和人为排放强度影响,NO₂则表现为1月最高、8月最低。2021年1—9月扬州市对流层HCHO、NO₂柱浓度月均值同比2020年分别增长4.0%,40.6%。空间分布特征显示,扬州市对流层HCHO和NO₂浓度高值区主要分布在扬州市南部,且浓度高值区域与重点排污企业分布情况较为一致,多为电力供热、工业锅炉、冶金、石化与化工、表面涂层等行业。相关性分析显示,对流层HCHO与气温、臭氧浓度呈显著正相关,而NO₂与气温、臭氧浓度呈显著负相关。     

生物蛭石柱处理生活污水中氨氮的效果研究

研究了生物蛭石柱对模拟城镇生活污水中污染物氨氮的去除效果。结果表明,生物蛭石柱对NH4^＋-N去除效果与空白蛭石柱去除效果相比明显且稳定,去除率大于85％。从机理分析,生物蛭石柱对NH4^＋-N的去除主要依靠离子交换吸附和生物硝化的协同作用。蛭石挂膜迅速,挂膜后生物蛭石的硝化作用明显。     

Particle size distribution and pollutants in road-deposited sediments in different areas of Zhenjiang,China

An understanding of road-deposited sediment (RDS) characteristics on an impervious surface is essential to estimate pollutant washoff characteristics and to minimise the impacts of pollutants on the water environment. A total of 62 RDS samples were collected from four different land-use types (commercial, residential, intense traffic and riverside park) in Zhenjiang City, China. The samples were fractionated into seven grain-size classes and analysed for particle size distribution and concentrations of pollutants. The samples are found to consist predominantly of fine particles (60–80%, <250 μm). The maximum mean concentrations of zinc, lead and copper were 686.93, 589.19 and 158.16 mg/kg, respectively, with the highest metal concentrations found in samples from the intense traffic area. The maximum mean contents of organic matter (12.55%), nitrogen (6.31 mg/g) and phosphorus (5.15 mg/g) were found in samples from the commercial area. The concentrations of heavy metals were highest in the smallest particle size fraction analysed (63 μm). The organic matter and nitrogen content generally increased with decreasing particle sizes in the <500-μm particle size range. The results also revealed that most of the total nitrogen (TN) is attached to the finer sediments and that to effectively reduce TN loads in particulates, treatment facilities must be able to remove the finer particles (down to 125 μm for TN).     

3种苯胺类化学品在好氧污水处理模拟系统中的降解特性

采用好氧生化污水处理模拟实验方法,研究了不同水力停留时间(hydraulic retention time,HRT)下4-硝基苯胺、4-异丙基苯胺和2-氯-4-硝基苯胺的去除率.结果表明,HRT为6 h、12 h和24 h时,系统DOC去除率依次为70.2%、80.3%和88.3%,4-硝基苯胺去除率分别为48%、64.7%和75%,4-异丙基苯胺的去除率分别为66%、76%和91%,提高HRT可促进溶解性有机碳和苯胺类化学品的去除.2-氯-4-硝基苯胺在不同HRT条件下较难去除,去除率平均值低于20%.生物降解动力学实验结果表明,4-硝基苯胺、4-异丙基苯胺和2-氯-4-硝基苯胺在3 g·L~(-1)好氧活性污泥中的降解符合一级动力学方程,回归系数大于0.95,生物降解半衰期依次为6.01 h、16.16 h和123.75 h.异丙基对苯胺类化学品生物降解具有积极作用,而硝基和氯原子等基团抑制生物降解性.     

Effect of culture conditions on the formation of struvite by Myxococcus xanthus

The amount of struvite (MgNH₄PO₄·6H₂O) produced by Myxococcus xanthus as well as the culture parameter values (pH, total phosphorus, total Kjeldahl nitrogen) were dependent on the culture medium used. Struvite formation started during the exponential phase and the maximum concentration was observed at the beginning of stationary growth phase. The addition of each medium component to the liquid culture influenced the amount of crystal produced. This amount did not depend on the pH increase during the culture period. The moment of the bacterial growth phase, at which each medium component was added, influenced the struvite formation.     

Varying water column stability controls the denitrification process in a subtropical reservoir, Southwest China

Reservoirs are regarded as hotspots of nitrogen transformation and potential sources of nitrous oxide（N₂O）. However, it remains unclear how the hydrological conditions due to dam construction control the processes of nitrogen transformation in reservoir waters. To address this issue, we examined the spatial-temporal characteristics of nitrate concentrations, δ¹⁵N-NO₃^-, δ¹⁸O-NO₃^-, δ¹⁸O-H₂O, relative...     

Effects of hydraulic retention time on net present value and performance in a membrane bioreactor treating antibiotic production wastewater

• The membrane bioreactor cost decreased by 38.2% by decreasing HRT from 72 h to 36 h. • Capital and operation costs contributed 62.1% and 37.9% to decreased costs. • The membrane bioreactor is 32.6% cheaper than the oxidation ditch for treatment. • The effluent COD also improved from 709.93±62.75 mg/L to 280±17.32 mg/L. • Further treatment also benefited from lower pretreatment investment. A cost sensitivity analysis was performed for an industrial membrane bioreactor to quantify the effects of hydraulic retention times and related operational parameters on cost. Different hydraulic retention times (72–24 h) were subjected to a flat-sheet membrane bioreactor updated from an existing 72 h oxidation ditch treating antibiotic production wastewater. Field experimental data from the membrane bioreactor, both full-scale (500 m³/d) and pilot (1.0 m³/d), were used to calculate the net present value (NPV), incorporating both capital expenditure (CAPEX) and operating expenditure. The results showed that the tank cost was estimated above membrane cost in the membrane bioreactor. The decreased hydraulic retention time from 72 to 36 h reduced the NPV by 38.2%, where capital expenditure contributed 24.2% more than operational expenditure. Tank construction cost was decisive in determining the net present value contributed 62.1% to the capital expenditure. The membrane bioreactor has the advantage of a longer lifespan flat-sheet membrane, while flux decline was tolerable. The antibiotics decreased to 1.87±0.33 mg/L in the MBR effluent. The upgrade to the membrane bioreactor also benefited further treatments by 10.1%–44.7% lower direct investment.     

污泥停留时间对单级好氧生物除磷的影响

以丙酸钠为单一碳源,设置4组不同污泥停留时间(SRT)的SBR(R1:SRT=9 d;R2:SRT=12 d;R3:SRT=18 d;R4:SRT=24 d),考察SRT对单级好氧生物除磷的影响。实验结果表明,当SRT分别为9、12、18和24 d时除磷效率分别为34.2%、85.0%、93.3%和76.7%,单位VSS除磷量分别为1.97、4.62、4.70和3.59 mg-P/g-VSS,SVI分别稳定在89、93、98和123 mL/g左右。随着SRT增大,系统除磷效率及单位VSS除磷量先升高后下降,并在SRT=18 d时达到最大值,而污泥沉降性能逐渐变差。分析各组反应器中内聚物的变化表明,R1中的微生物在外源基质消耗阶段利用糖原质的分解合成多β羟基烷酸盐(PHA),但PHA消耗阶段没有磷酸盐的大量吸收,表现出聚糖菌的代谢方式;R2、R3和R4中的微生物在外源基质消耗阶段通过TCA循环合成PHA,在PHA消耗阶段大量合成聚磷,表现出聚磷菌的代谢方式。     

固定床三维电极反应器深度处理炼油废水

以不锈钢板为阴阳主电极,以柱状活性炭为感应粒子电极,构建固定床三维电极反应器, 并用其深度处理炼油废水。考察了施加电压、水力停留时间、废水pH和曝气量对COD去除效果的影响。实验结果表明,在施加电压10 V、水力停留时间60 min、废水pH=7.0、曝气量120 L/h的优化工艺条件下,处理后出水的COD=27.1 mg/L,满足“超滤—反渗透”单元对进水COD的要求（COD<30.0 mg/L）。