杭锦2#土复合吸附剂对磷的吸附动力学

通过静态试验考察杭锦2#土/聚合硫酸铝复合吸附剂对生活污水中磷酸根的吸附特性,研究吸附过程的动力学模型,并从动力学角度探讨其吸附机理.结果表明,在杭锦2#土/聚合硫酸铝复合吸附剂用量5g·L-1、吸附时间60 min、废水pH值6.0、温度25℃、磷初始质量浓度小于16.72 mg·L-1条件下,磷酸根的去除率在96％以上;复合吸附剂对磷酸根的吸附动力学特征符合假二级方程,吸附速率在前10 min为内扩散控制,后期由膜扩散和内扩散共同控制,且膜扩散占主导地位;磷酸根的初始浓度越高,吸附质粒子的表观内扩散系数和表观传质系数越小;使用不同再生次数的再生吸附剂(添加量为5g·L-1)处理16.72 mg·L-1含磷生活污水,随着再生次数的增加,吸附能力有所下降,但磷酸根的去除率均大于89％.     

杭锦2~#土复合吸附剂对磷的吸附动力学

通过静态试验考察杭锦2#土/聚合硫酸铝复合吸附剂对生活污水中磷酸根的吸附特性,研究吸附过程的动力学模型,并从动力学角度探讨其吸附机理。结果表明,在杭锦2#土/聚合硫酸铝复合吸附剂用量5 g.L-1、吸附时间60 min、废水pH值6.0、温度25℃、磷初始质量浓度小于16.72 mg.L-1条件下,磷酸根的去除率在96%以上;复合吸附剂对磷酸根的吸附动力学特征符合假二级方程,吸附速率在前10 min为内扩散控制,后期由膜扩散和内扩散共同控制,且膜扩散占主导地位;磷酸根的初始浓度越高,吸附质粒子的表观内扩散系数和表观传质系数越小;使用不同再生次数的再生吸附剂（添加量为5 g.L-1）处理16.72 mg.L-1含磷生活污水,随着再生次数的增加,吸附能力有所下降,但磷酸根的去除率均大于89%。     

北京城区雨水径流的污染及控制

随着城市化发展，不透水地面面积增加，雨水径流的污染性也相应增长，它已成为不可忽视的污染源。文章分析了北京市雨水径流的污染源，估算了其污染量，并提出了多种控制径流污染的措施。     

广州城市道路雨水径流的水质特征

城市道路雨水径流中富含交通活动所产生的大量石油类、悬浮固体和重金属等污染物,能够对受纳水体的水质造成明显的破坏并影响水生生态。对广州市内道路某路段发生的七场路面雨水径流进行了降雨量、径流量的同步监测和径流样品的水质分析,结果表明,广州城市道路雨水径流中营养盐的含量较低,但COD值较高,且可生化性差,石油类和重金属的含量也较高。其中石油类、COD、悬浮固体和重金属Pb的污染水平虽然与国内其他城市的研究结果在同一范围,但都高于国外发达国家的研究结果,反映出我国在道路路面环境维护和管理上与国外的差距。对照我国地表水环境质量标准,广州城市道路雨水径流中的石油类、COD、悬浮固体和Pb等指标都大大超过III类标准,表明道路径流若不经处理直接排放进入地表水体,可能对受纳水体主要是珠江的水质造成严重影响。     

雨水径流对景观水体中多环芳烃污染特征的影响

以北京市长河湾流域某排污口附近景观水体为研究对象,通过对水体中PAHs的连续检测,研究了雨水径流对景观水体中PAHs污染特征的影响,以期为景观水体中PAHs的控制和管理提供科学依据.结果表明,长河湾景观水体中∑16PAHs在降雨时的浓度变化与降雨强度及降雨量有关,长河湾水体中溶解态PAHs组分以3环和4环为主,2环组分所占的比例最少.水体底部沉积物中PAHs含量明显高于岸边,沉积物中∑16PAHs含量约为229.2μg.kg-1,岸边土壤中∑16PAHs含量约为185.6μg.kg-1,低于国内外一些水域沉积物中PAHs污染浓度.     

氧化铜尾矿对水溶液中磷的吸附

研究不同pH条件下氧化铜尾矿颗粒对水溶液中磷的吸附特性.结果表明:Langmuir方程能很好地描述氧化铜尾矿对磷素的等温吸附特征;影响氧化铜尾矿对磷素吸附的因素主要有尾矿的比表面积、钙及铁氧化物含量、水溶液中磷素的初始浓度、体系pH值等;其吸附量随着钙及铁氧化物含量的增加、磷素初始浓度的提高以及体系pH值的降低而增大;其吸附机制主要为物理吸附和化学吸附.     

广州城区“雨水-雨水径流-河涌”污染链的特征

正在点源污染被逐步控制后,城市地面雨水径流已成为城市河流与湖泊等水体主要污染源.国内相关研究起步于20世纪80年代,之后在北京、上海、西安、珠海、澳门、天津、广州等城市开展.雨水、雨水径流及河涌的污染过程已经形成了一个完整的污染链,即雨水携带大气颗粒物降至地面,随之形成的雨水径流又携带地表污染物进入城市河涌,从而恶化河涌水质;然而,对"雨水-雨水径流-河涌"整个污染链的研究尚鲜见文献报道.     

中孔硅镁胶对水溶液中磷酸根的吸附性能

化肥、农药、含磷洗涤剂以及粪便,是废水中磷的主要来源,而磷浓度超标是引起水体中富营养化的主要原因之一.目前,国内外除磷的方法中主要有化学沉淀法、物理吸附法、离子交换法和微生物降解法等,吸附法因其工艺简单、运行可靠、操作灵活和无二次污染等特点备受关注.硅酸镁为多孔结构,属两性化合物,具有酸碱两种吸附性能,在聚醚精制过程中用于脱酸、脱臭、脱色及脱钾,在煎炸油处理和生物柴油加工过程中用于降低酸价;此外,硅酸镁还广泛地应用于脱除废水中的金属离子和染料.目前,国内外对三硅酸镁和六硅酸镁的报道较多,对其它镁硅配比的硅酸镁报道较少.本课题组系统地研究了不同镁硅物质的量之比的     

城市高架公路雨水径流的污染特征

对上海市内环高架一段路面的7场降雨径流进行监测,分析了径流中固体悬浮物和营养盐的变化特征,以期加深对城市高架公路径流污染物的认识和为高架公路径流净化工艺的选择提供理论支持。结果表明：溶解态氮、颗粒态磷是径流中TN和TP的主要输出形式;TP质量浓度变化与TSS基本一致,但TN质量浓度变化与TSS相关关系较弱;通过分析不同粒径固体悬浮物与污染物的相关性,发现〈45μm固体悬浮物是径流中营养盐吸附的重要载体,去除细小固体悬浮物是治理城市高架径流污染的有效途径。     

天津市路面雨水径流重金属污染特征

对天津市3条典型主要交通干线雨水径流中的Cr、Cd、Fe、Cu、Hg 5种重金属进行了取样监测,重点探讨了路面径流重金属的平均质量浓度、冲洗特征、重金属之间以及重金属与悬浮物之间的相关关系,并用聚类分析方法对降雨特征对重金属污染的影响进行了研究。结果表明,天津市路面雨水径流重金属污染严重,Fe、Cr和Cd质量浓度较高,污染贡献率大,为径流主要重金属污染物;重金属污染水平高于国内外城市研究结果,反映出天津市在道路路面环境维护和管理上与其他城市的差距。路面径流的重金属具有明显的径流初期冲洗效应,在径流的初始阶段,重金属质量浓度达到最大值,随着降雨和径流的延续,污染物质量浓度呈波浪性锯齿状下降,至降雨结束,重金属质量浓度最终趋于稳定。径流中不同种类重金属具有同源性,且与径流中的悬浮固体具有明显的相互依存关系,重金属主要以悬浮固体吸附的形式或重金属颗粒形式存在。通过聚类分析可知,重金属污染受降雨强度和前期晴天积累影响显著,其次是降雨量和降雨历时。     

Ammonia and phosphorus removal from agricultural runoff using cash crop waste-derived biochars

• Orange tree residuals biochar had a better ability to adsorb ammonia. • Modified tea tree residuals biochar had a stronger ability to remove phosphorus. • Partially-modified biochar could remove ammonia and phosphorus at the same time. • The real runoff experiment showed an ammonia nitrogen removal rate of about 80%. • The removal rate of total phosphorus in real runoff experiment was about 95%. Adsorption of biochars (BC) produced from cash crop residuals is an economical and practical technology for removing nutrients from agricultural runoff. In this study, BC made of orange tree trunks and tea tree twigs from the Laoguanhe Basin were produced and modified by aluminum chloride (Al-modified) and ferric sulfate solutions (Fe-modified) under various pyrolysis temperatures (200°C–600°C) and residence times (2–5 h). All produced and modified BC were further analyzed for their abilities to adsorb ammonia and phosphorus with initial concentrations of 10–40 mg/L and 4–12 mg/L, respectively. Fe-modified Tea Tree BC 2h/400°C showed the highest phosphorus adsorption capacity of 0.56 mg/g. Al-modified Orange Tree BC 3h/500°C showed the best performance for ammonia removal with an adsorption capacity of 1.72 mg/g. FTIR characterization showed that P = O bonds were formed after the adsorption of phosphorus by modified BC, N-H bonds were formed after ammonia adsorption. XPS analysis revealed that the key process of ammonia adsorption was the ion exchange between K⁺ and NH₄⁺. Phosphorus adsorption was related to oxidation and interaction between PO₄^3– and Fe³⁺. According to XRD results, ammonia was found in the form of potassium amide, while phosphorus was found in the form of iron hydrogen phosphates. The sorption isotherms showed that the Freundlich equation fits better for phosphorus adsorption, while the Langmuir equation fits better for ammonia adsorption. The simulated runoff infiltration experiment showed that 97.3% of ammonia was removed by Al-modified Orange tree BC 3h/500°C, and 92.9% of phosphorus was removed by Fe-modified Tea tree BC 2h/400°C.     

Cation exchange resin supported nanoscale zero-valent iron for removal of phosphorus in rainwater runoff

Self-made cation exchange resin supported nanoscale zero-valent iron （R-nZVI） was used to remove phosphorus in rainwater runoff. 80% of phosphorus in rainwater runoff from grassland was removed with an initial concentration of 0.72 mg. L-1 phosphorus when the dosage of R-nZVl is 8 g per liter rainwater, while only 26% of phosphorus was removed when using cation exchange resin without supported nanoscale zero-valent iron under the same condition. The adsorption capacity of R-nZVI increased up to 185 times of that of the cation exchange resin at a saturated equilibrium phosphorous concentration of 0.42 mg. L-1. Various techniques were implemented to characterize the R-nZVI and explore the mechanism of its removal of phosphate. Scanning electron microscopy （SEM） indicated that new crystal had been formed on the surface of R-nZVI. The result from inductive coupled plasma （ICP） indicated that 2.1% of nZVI was loaded on the support material. The specific surface area was increased after the load of nanoscale zero-valent iron （nZVI）, according to the measurement of BET-N2 method. The result of specific surface area analysis also proved that phosphorus was removed mainly through chemical adsorption process. X-ray photoelectron spectroscopy （XPS） analysis showed that the new product obtained from chemical reaction between phosphate and iron was ferrous phosphate.     

Transferral of HMs pollution from road-deposited sediments to stormwater runoff during transport processes

Ratio of turbidity and TSS (Tur/TSS) was used to characterize PSD of stormwater particles. Pb and Zn preferred to accumulate in finer RDS, while Cu, Cr and Ni in coarser RDS. HMs pollution in stormwater particles increased linearly with Tur/TSS. Dissolvability of HMs and PSD variations contribute to the differences between RDS and stormwater. Stormwater runoff, derived from the wash-off of road-deposited sediments (RDS), contains elevated heavy metal (HM) concentrations and, thus, imposes an increasing threat to urban aquatic ecosystems. In-depth understanding of the variations of HMs pollution from RDS to stormwater during transport processes facilitates the development of effective RDS and stormwater control strategies. Toward this end, the distribution of HMs (Cu, Pb, Zn, Cr, and Ni) in RDS and stormwater were investigated simultaneously. The results show a preferential accumulation of Pb and Zn in the finer (<38.5 μm) RDS, and Cu, Cr and Ni in the coarser (38.5–150 μm) RDS. For stormwater, n.d.~48.6% of HMs fractionated into the dissolved phase, and stormwater particles constitute the primary carriers of HMs. Furthermore, the accumulation of HMs in stormwater particles increased linearly with finer particle size distributions (PSD). Geoaccumulation index (I_geo) highlighted the predominant pollution of both RDS and stormwater particles by Cu, Pb and Zn. Nonetheless, Cu, Pb, and Ni mostly contributed the potential ecological risk of RDS, whereas Cu, Pb, and Zn mainly contributed that of stormwater particles. Moreover, contamination by Cu, Pb and Zn was significantly higher in stormwater particles than that in RDS. These differences are attributable to the solubility and size-dependent accumulation of HMs in RDS, as well as the PSD variations during transport processes. The study outcomes highlight the importance of very fine (nano- and submicron- scale) RDS in stormwater pollution and the necessity of control.     

基于场降雨的北京某高架桥雨水径流中多环芳烃污染特征

以北京市某高架桥的典型场次雨水径流作为研究对象,通过对多场雨水径流中多环芳烃(PAHs)的监测,研究了高架桥雨水径流中PAHs的污染特性以及冲刷规律.结果表明,随着降雨历时的增加,雨水径流中PAHs浓度呈现先增加后减小的变化趋势,实验均值中w(Flu)/w(Pyr)为0.94,因此,高架桥雨水径流中溶解态PAHs主要来源于石油燃料的不完全燃烧.雨水径流中溶解态PAHs以三环、四环组分为主,五和六环次之,二环组分最少.高架桥雨水径流中PAHs存在浓度和质量初期冲刷现象,∑_(16)PAHs和四环组分在不同降雨事件中均存在浓度初期冲刷现象,∑_(16)PAHs及各环组分在降雨强度大、降雨历时长的场降雨存在明显的质量初期冲刷现象,而降雨强度小的场降雨质量初期冲刷不明显.     

Temporal variation of heavy metal pollution in urban stormwater runoff

Stormwater runoff from three types of urban surfaces, a parking lot, a street, and a building roof, was monitored during four rainfall events that occurred in the one-year period from June 2009 to June 2010. The event mean concentrations (EMC) of dissolved copper (Cu), lead (Pb), zinc (Zn), manganese (Mn), and iron (Fe) exceeded China’s National Water Quality Standards for Surface Water. The degree of heavy metal contamination was related to the type of underlying surfaces. Additionally, the concentration of dissolved heavy metals peaked shortly after the runoff began and then declined sharply as a result of adequate flushing. First flush effects of varying degrees were also observed during all of the monitored rainfall events based on the first flush ratio (FF₂₅). Redundancy analysis revealed that four environmental variables (rainfall depth, intensity, antecedent dry weather period and type of underlying surface) had significant effects on the strengths of the first flush effects, accounting for 72.9% of the variation in the FF₂₅. Dissolved metals presented varying first flush effects on different underlying surfaces that occurred in the following relative order: parking lot>roof>road for low intensity and high runoff volume rainfall events; parking lot>road>roof for high intensity and low runoff volume events. The relative strength of the first flush for dissolved heavy metals was Fe, Mn>Cu, Zn>Pb.     

蔬菜地土壤磷提取及模拟径流中磷素潜在流失的影响

蔬菜地磷素流失是一种典型农业非点源污染类型。通过观测地表径流中溶解态反应磷(DRP)、生物可利用磷(BAP)可以监测土壤磷素流失程度。受到各种客观条件的限制,这两个指标比较难于获取,而土壤中的总磷(TP)、Olsen(OP)、Mehlich-1(M-1P)和水溶性磷(Pw)可以通过常规分析手段获取。本文选取27个典型蔬菜样地,分析测定各样地土壤中的总磷(TP)、Olsen(OP)、Mehlich-1(M-1P)和水溶性磷(Pw)四个磷提取变量,采用了经典方法计算土壤磷流失潜能指标——磷吸持饱和度(DPS)。同时采用模拟径流实验得出典型蔬菜样地地表径流样中溶解态反应磷(DRP)、生物可利用磷(BAP)。结果表明:M-1P、Pw与DPS呈极显著正相关,相关系数分别达到了0.85和0.74(p<0.01);而M-1P、Pw与DRP浓度相关系数(r2=0.843和0.786,p<0.01)大于TP、OP与DRP浓度的相关系数(r2=0.554和0.722,p<0.01)。结论认为,通过测定M-1P、Pw和计算DPS能比较准确、便捷地预测土壤径流磷素流失风险程度。     

Road-deposited sediments mediating the transfer of anthropogenic organic matter to stormwater runoff

Environmental Geochemistry and Health - It has been regarded that road-deposited sediment (RDS) is one of the important sinks of anthropogenic pollutants as well as the major source of pollutants...     

不同进水有机物浓度下移动床生物膜反应器(SBMBBR)脱氮除磷特性

考察了不同进水有机物浓度下厌氧/好氧序批式移动床生物膜反应器（SBMBBR）污染物去除特性,实验结果表明,SBMBBR能够实现低碳源污水中氮和磷的同步去除,在进水TN和TP浓度分别为116.7 mg.L-1和11.5 mg.L-1、COD浓度为456 mg.L-1的条件下,TN和TP去除率分别达到94.3%和92.2%以上.反应器除磷是基于常规生物除磷和反硝化除磷过程实现的,脱氮主要是基于好氧段发生的同时硝化反硝化（SND）作用而完成.由于生物膜内部存在的DO扩散梯度,在好氧阶段混合液DO浓度不断提高的条件下反应器内具有良好SND反应的发生.进水COD浓度由149 mg.L-1提高至456 mg.L-1的过程中,反应器硝化效果不变,反硝化和除磷效果改善.反应器在好氧阶段pH值基本维持在7.0—7.1之间,为各类菌群的生长创造了条件.碱度变化较pH值更能反映硝化和反硝化反应发生的程度.反应器中微生物相丰富,生物膜以丝状菌为骨架,其上附着大量的球状菌和杆状菌,而悬浮活性污泥中丝状菌较少,形成了由细菌、真菌到原生动物和后生动物的复杂的生态体系,为系统取得稳定的污水处理效果提供了有效的保证.