国内外雨水、污水和中水在城市绿地系统中的应用进展及发展现状

由于人口增加,城市化程度加快,水资源短缺日趋加剧,文章依据可持续发展理念,提出雨水、污水和中水在城市绿地系统中的应用,对指导城市供水、用水、节水、污水处理和水资源保护,促进城市水系统的良性循环有重要作用;指出它能充分发挥生产潜力,使资源最佳化,非常适合建设节约型城市,具有广阔的应用前景;并对国内外雨水、污水和中水在城市绿地系统中的应用方法及相关实例进行了综述,是环境保护中最具说服力的应用事例,旨在使人们形成节约资源、尊重自然的生态观念。     

Effects of Pd doping on N<Subscript>2</Subscript>O formation over Pt/BaO/Al<Subscript>2</Subscript>O<Subscript>3</Subscript> during NO<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript> storage and reduction process

N₂O is a powerful greenhouse gas and plays an important role in destructing the ozone layer. This present work investigated the effects of Pd doping on N₂O formation over Pt/BaO/Al₂O₃ catalyst. Three types of catalysts, Pt/BaO/Al₂O₃, Pt/Pd mechanical mixing catalyst (Pt/BaO/Al₂O₃ + Pd/Al₂O₃) and Pt-Pd co-impregnation catalyst (Pt-Pd/BaO/Al₂O₃) were prepared by incipient wetness impregnation method. These catalysts were first evaluated in NSR activity tests using H₂/CO as reductants and then carefully characterized by BET, CO chemisorption, CO-DRIFTs and H2-TPR techniques. In addition, temperature programmed reactions of NO with H2/CO were conducted to obtain further information about N₂O formation mechanism. Compared with Pt/BaO/Al₂O₃, (Pt/BaO/ Al₂O₃ + Pd/Al₂O₃) produced less N₂O and more NH3 during NO _x storage and reduction process, while an opposite trend was found over (Pt-Pd/BaO/Al₂O₃ + Al₂O₃). Temperature programmed reactions of NO with H₂/CO results showed that Pd/Al₂O₃ component in (Pt/BaO/Al₂O₃ + Pd/Al₂O₃) played an important role in NO reduction to NH₃, and the formed NH3 could reduce NO _x to N₂ leading to a decrease in N₂O formation. Most of N₂O formed over (Pt-Pd/BaO/Al₂O₃ + Al₂O₃) was originated from Pd/BaO/Al₂O₃ component. H₂-TPR results indicated Pd-Ba interaction resulted in more difficultto- reduce PdOx species over Pd/BaO/Al₂O₃, which inhibits the NO dissociation and thus drives the selectivity to N₂O in NO reduction.

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适宜处理分散性生活污水的人工湿地除磷填料的筛选及改性

为提高人工湿地除磷效能,从沸石、陶粒、萤石、膨胀蛭石、石灰石、麦饭石、火山岩、牡蛎壳、钢渣和废砖块这10种具有较高磷素饱和吸附量的填料中,筛选出钢渣、沸石和石灰石3种适宜处理分散性生活污水的人工湿地填料,并分别使用不同浓度梯度的酸(碱)、盐对3种填料进行改性,以增强其除磷能力。研究结果表明,钢渣、沸石和石灰石分别经2 mol/L AlCl3、2 mol/L NaOH及2 mol/L AlCl3、0.5 mol/L AlCl3溶液改性后,磷素吸附量达到最高值(0.272、0.0801和0.351 mg/g),而双常数方程能更好地描述优选填料对生活污水中磷的吸附动力学过程,综合考虑填料的吸附效果、成本及来源,改性石灰石是人工湿地处理分散性生活污水时较为理想的除磷填料;此外,填料经铝改后,氮磷吸附效果普遍优于其他改性条件,且Al-P有利于植物直接吸收利用,含铝废水来源广泛,故利用铝改液处理人工湿地填料具有较高的应用推广价值。     

上海市滩涂湿地生态系统健康评价及成因分析

上海沿江沿海地区是我国重要的滩涂湿地分布区，其滩涂湿地生态系统健康对上海乃至长三角地区的生态安全具有重要意义。基于“压力-状态-响应（PSR）”模型，构建了上海市滩涂湿地生态系统健康评价指标体系，采用熵权综合评价法对研究区域生态系统健康状况进行评价，并设定了相应的健康评价分级标准。结果表明：杭州湾北沿边滩、南汇边滩、浦东边滩、宝山边滩、长兴岛周缘边滩、横沙岛周缘边滩、崇明南滩、崇明北滩均处于亚健康状态；崇明西滩处于较健康状态；而崇明东滩和九段沙湿地处于健康状态。过度围垦、环境污染、互花米草（Spartina alterniflora Loisel）〖JP2〗入侵等胁迫因子是上海市滩涂湿地面临的主要压力。在多重胁迫因子作用下，近30 a〖JP〗来上海滩涂湿地面积锐减，生态系统结构改变，生态功能退化。应重点控制滩涂开发强度，减少污染物排放，并加强对上海市滩涂湿地尤其是大陆边滩的保护，以维护湿地生态系统健康，保障区域生态安全     

铁铝复配混凝剂处理低温低浊水

针对北京某水库水在冬季呈现低温低浊特性,以此为原水的某水厂在该期间常会出现出水余铝超标现象的问题,通过烧杯实验研究不同投药量下聚合氯化铝(PAC)以及它与三氯化铁(FeCl3)不同复配比形成混凝剂对冬季北京某水库水的处理效果。结果表明,复配药剂存在最佳的Fe/Al摩尔复配比为1/5,此时余铝、有机物去除效果较其他配比混凝剂高。在此配比下,当PAC投药量为0.03 mmol/L时,水中残余铝量取得最低值0.0063 mg/L。相同投药量复配药剂的浊度去除效果比单独使用PAC的浊度去除效果略弱。当投药量为0.06 mmol/L时,Fe/Al摩尔比为1/5的复配混凝剂,能使浊度降至0.4 NTU左右。此外,复配药剂的投药量小,投药范围更宽,易于实际投药操作;同时复配药剂还适于常温及偏中性水源水的处理。规模为5 m3/h中试实验也证明,采用铁铝复配混凝剂连续运行,可获得良好的浊度、余铝去除效果。     

Fenton氧化工艺在某化工园区集中式污水处理厂升级改造工程中的应用

针对江苏省某化工园区集中式污水处理厂出水COD和TP高于DB32/939—2006《江苏省化学工业主要水污染物排放标准》规定的排放限值的情况,采用Fenton氧化工艺对该污水处理厂装置进行升级改造。小试最佳工艺条件为:初始污水pH 3.0~3.5,H_2O_2(质量分数30%)加入量0.8 m L/L,FeSO_4·H_2O加入量0.8 g/L,反应时间120min,Fenton氧化反应结束后中和反应的适宜pH约为7.0。升级改造工程包括2套并联运行的处理能力各为10 km~3/d的Fenton氧化系统,装置稳定运行后最终控制H_2O_2加入量为150 L/h,FeSO_4·7H_2O溶液加入量为700 L/h,相应的处理后出水COD和TP分别稳定在60 mg/L和0.4 mg/L以下,可达标排放。每吨污水的处理药剂成本约为0.9元。     

生物炭对小麦种子萌发与幼苗生长的植物毒理效应

为明确生物炭对植物的毒性效应,以石英砂+生物炭水浸提液培养方法研究不同剂量生物炭对小麦种子萌发与幼苗生长的影响。结果表明:在不同剂量(0.0、10.0、20.0、40.0、80.0、160.0 g·kg~(-1))生物炭水浸提液处理下,虽然小麦发芽率较对照组无显著性变化(P0.05),但根、芽生长表现出低剂量促进高剂量抑制,且在160.0 g·kg~(-1)时抑制率最大,分别为18.11%和22.22%。在幼苗的生长期(11 d),高剂量生物炭对幼苗根生长的抑制作用增强,160.0 g·kg~(-1)处理下抑制率显著增加至55.59%(P0.05)。此外,当生物炭剂量较低时,小麦幼苗根、叶中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)活力增加;随生物炭剂量的增加,3种抗氧化酶活力降低,丙二醛(MDA)含量升高,幼苗生长出现生理损伤,表现出明显植物毒性效应。     

Gamma irradiation-induced decomposition of sulfamethoxazole in aqueous solution: the influence of additives,biological inhibitory,and degradation mechanisms

Sulfamethoxazole (SMX) was decomposed by using gamma irradiation in the presence of different additives such as NO₃ ⁻, NO₂ ⁻, Cr(VI), 2-propanol, and tert-butanol. The results demonstrated that NO₃ ⁻, NO₂ ⁻, 2-propanol, and tert-butanol inhibited SMX radiolytic removal. However, there existed a synergetic effect for radiolytic removal of the mixture containing SMX and Cr(VI). At an absorbed dose of 150 Gy, the removal percentages of SMX and Cr(VI) in the mixture were 73.5 and 84.6%, respectively, which was higher than the removal percentages of 70.6 and 4.1% for the single component of SMX and Cr(VI). This provides us an insight into treating the combined pollution in micro-polluted water. The SMX radiolytic removal followed a pseudo first-order reaction kinetic model, and the rate constant ratios of ·OH, e_aq ⁻, and H· towards SMX radiolysis were 10.4:1:2.9. In addition, 24-h bio-inhibitory to the macroalgae of SMX solution during gamma irradiation reached the maximum of 0.85 at an adsorbed dose of 100 Gy, then gradually decreased with the increasing adsorbed dose. Based on LC-MS analysis and quantum chemical calculation, the degradation intermediates were determined and concluded that SMX radiolytic removal was mainly via ·OH radical attack and direct decomposition of SMX molecule by gamma ray.

     

菲和铬(Ⅵ)单一及复合暴露对土壤微生物多样性的影响

有机物和重金属已成为我国土壤环境中常见的2类污染物质,二者间复合污染引起的土壤生态环境风险不容忽视。本研究以多环芳烃模式物菲和典型重金属铬(VI)作为受试物质,采用PCR-DGGE分子指纹图谱技术,探讨这2种污染物单一及复合暴露对土壤微生物群落多样性的影响,并选用主成分分析、聚类分析和戴斯系数3种算法对微生物群落相似性进行了比较。结果表明,在暴露实验第1天,菲单一暴露低浓度组中微生物群落相似性产生了极为明显的变化,而到第7天时,菲和铬(VI)单一暴露高浓度组均对微生物群落结构相似性产生最大程度的影响;采用香农指数法评价微生物群落的多样性,发现在暴露实验第7天,菲和铬(VI)单一暴露高浓度组对微生物群落多样性的影响比复合暴露高浓度组更强,二者复合暴露的相互作用方式表现为拮抗效应。本研究证明低浓度菲短期暴露的效应高于高浓度暴露结果,因而多环芳烃菲自身及其在复合暴露中所扮演的角色尤其值得关注。     

三乙胺降解菌SYA-1的分离、降解性能与动力学

从农药废水处理池的活性污泥中分离筛选得到1株高效三乙胺降解菌株SYA-1,根据菌株SYA-1的形态特征、生理生化特性和16S rRNA基因序列同源性分析,此菌株鉴定为Achromobacter sp.。菌株SYA-1能以三乙胺为惟一碳、氮源生长,并在24 h内完全降解200 mg/L的三乙胺。环境因素影响实验表明,在温度30℃,初始pH 7.0,NaCl浓度≤10 g/L条件下,菌株SYA-1生长良好且对三乙胺的降解效率最佳;金属离子对菌株生长和三乙胺降解的抑制程度表现为:Cu2+Co2+Ag+Cd2+Fe3+Pb2+。菌株SYA-1降解三乙胺的动力学过程可用Haldane模型模拟,其参数为μmax=0.123h-1;K s=82 mg/L;K i=215 mg/L。为含三乙胺废水的生物降解提供了理论依据和菌株资源。