生物氧化塘是处理中小城镇污水的好方法

生物氧化塘是生物处理方法最早的一种,它是利用水中存在的微生物和藻类处理污水的天然或人工池塘。生物氧化塘处理污水的机理是:氧化塘中污水合的有机物通过两类微生物的新陈代谢而去除,一类是异养微生物,它将有机物氧化降解而产生能量和合成新的细胞;另一类是藻类,它通过光合作用固定二氧化碳合成新细胞和放出氧气。藻类光合作用放出的氧是供异养微生物和原生动物所利用,对污水中的有机污     

藻类对有机污染物生物吸附的研究进展

随着工业的迅猛发展,越来越多的有毒有机污染物被排放到环境中,进而引起一系列环境问题。大量研究表明,生物吸附已经成为去除有毒有机污染物的重要方法,而藻类作为一种理想的生物吸附剂,具有良好的吸附和降解有机污染物的能力。概述了藻类对染料、酚类、多环芳烃三种具有代表性的有毒有机污染物的生物吸附。     

基于菌藻共生的污水处理与资源化新技术研究进展

基于微藻生物处理技术的菌藻共生培养体系，不仅能实现污水资源化，还可利用菌藻间相互作用增强处理系统的污染物去除能力及藻类生物质回收潜力。菌藻共生体系还可耦合CO₂固定，结合工业烟气中高浓度的CO₂进行微藻培养可同时实现碳减排与降低微藻额外曝气补充CO₂的能耗，符合“碳中和”的发展需求。本文对菌藻共生体系在污水处理及资源化过程的作用机理、相互作用形式及影响因素进行了系统介绍，对菌藻工程在污染物降解、CO₂固定及微藻生物质产品的回收潜力展开综述。研究菌藻间营养交换、信息传递及基因水平的互相适应作用形式，发现选择适宜的共生菌藻组合培养可有效增强污水中污染物去除效果且提高CO₂固定效率。菌藻共生效应对藻类生物组分(蛋白质、脂质和碳水化合物等)积累存在增强效应与选择能力，通过污水类型合理遴选藻种及对应共生菌、调节接种比例与培养条件，可提高工业规模上收获微藻并进一步加工生产生物燃料、医疗保健食品等产品的效率。菌藻共生耦合废水处理、CO₂固定及生物质能回收于一体，有利于构...     

衣藻细胞的重金属结合特性及其抗性机制

衣藻(Chlamydomonas)是隶属于绿藻门团藻目衣藻属的单细胞真核藻类。因其独特的结构与功能特性,衣藻具有高效的重金属结合能力,同时也表现出很高重金属抗性。目前利用衣藻去除工业污水中有害重金属,以及开展生物冶金等方面的研究已成为热点。文章对衣藻细胞的重金属结合特性,及其耐受重金属胁迫的抗性机制进行了深入地探讨和总结。主要内容包括:衣藻吸附重金属的动力学特征、影响吸附效率的因素、固定化衣藻对重金属的吸附与解吸附,衣藻细胞内的重金属结合因子、重金属转运蛋白等。     

不同生物接触氧化方法对藻类的去除效果比较及其途径分析

比较了3种生物接触氧化法对富营养化水源水中藻类的去除效果，探讨其去除藻类的途径。试验结果表明：淹没式曝气生物陶粒滤池（I型）在4-6m/h过滤速度条件下，对藻类总数的去除效率稳定，平均为70%左右；采用YDT弹性立体填料的中心导流筒曝气生物接触氧化法（Ⅱ型）与直接微孔曝气生物接触氧化法（Ⅲ型），在试验初期对藻类总数的去除率较低，平均去除率分别为60.2%、51.6%。但随着生物膜厚度的增加，试验后期对藻类的去除效果逐步得到提高，平均达70%以上。生物膜对藻类的生物絮凝、吸附、生物膜的脱落沉降等是生物接触氧化法去除藻类的主要途径。     

藻对酚类物质的吸附降解研究进展

酚类物质的广泛用使其成为水体、沉积物以及水生生物体等环境介质中普遍检出的有机污染物,引起公众极大的关注。目前,关于藻类在酚类物质污染修复方面的研究工作取得了重要进展。文章综述了藻生物质吸附剂生物吸附和活藻生物富集、转化及降解酚类物质的最新研究动态,比较分析了吸附、降解2种去除途径的特性、影响因素和机理,并对固定化藻和藻菌混合体的应用、降解途径、吸附机理等方面的研究趋势进行了展望。     

铬污染场地生物吸附修复技术研究进展

工业废水、废渣中铬的存在对环境和人体有着潜在危害。生物吸附修复技术因为其技术上的可行性、经济性以及对环境影响较小的特点,成为从污染场地中去除有毒金属最具前景的技术之一。介绍了铬污染来源、铬的主要存在形式及其毒性,同时对铬吸附机制进行了分类讨论;分析了细菌、真菌、藻类、植物以及其他改性材料对铬的生物吸附特性,分别阐释了其吸附机理及主要影响因素;提出了生物吸附机理的研究、生物吸附参数的优化、生物吸附剂的化学改性是实现生物吸附修复技术规模化应用的关键。     

化学生物絮凝工艺污染物去除试验研究

化学生物絮凝污水处理工艺是一种新的一级强化处理工艺。该工艺在传统的化学混凝的基础上将沉淀池内的污泥回流至化学生物絮凝池,利用化学混凝和污泥吸附的协同作用去除污水中的污染物。中试试验结果表明,聚合硫酸铝铁絮凝剂投加量为70mg/L,PAM投加量为0.5m g/L时,COD、TP和SS去除率分别为61.8%、74.5%和74.6%。化学生物絮凝池内污泥富集了未反应的絮凝剂,这部分絮凝剂对污水中TP具有很好的去除作用。化学生物絮凝池内污染物的沿程分析显示,回流污泥与污水充分接触可促进TP的进一步去除。     

化学改性生物炭介导水中新污染物去除的研究进展

新污染物是一类浓度相对较低但毒性很高的污染物，可以在生物体内富集，并通过食物链转移到人体，对环境生态和人体健康都构成很大威胁。此外，新污染物在环境中的危害具有潜在性、隐蔽性和持久性，因此选择适当的方法对新污染物进行风险管控具有重要的现实意义。在我国推行“双碳行动”的大背景下，人们对生物炭吸附去除新污染物产生了广泛的研究兴趣。然而，需要注意的是，原始生物炭在许多应用中存在局限性，例如吸附能力弱、选择性差、化学稳定性较低等。因此，有必要对生物炭进行改性，以提高其在水污染处理中的应用。目前，生物炭改性方法中，化学改性是最为广泛应用的一种方法。本文介绍了三种常见的化学改性方法，包括酸改性、碱改性以及金属盐/氧化物改性，并阐述它们提高生物炭物理化学性能的机制。此外，还分析了化学改性生物炭介导新污染物去除的增效机制，主要涉及吸附和高级氧化过程。总结了近五年来化学改性生物炭对药品及个人护理产品(PPCPs)、内分泌干扰物(EDCs)、全氟化合物(PFCs)和微塑料(MPs)等典型新污染物去除方面的研究进展。最后，本文提出了化学改性生物炭介导新污染物去除的未来探索方向，旨在为水中新污染物的绿色高效去除...     

多环芳烃及其衍生物在SBR/MBBR工艺中的分布与去除

多环芳烃(PAHs)是一类重要的持久性有毒有机污染物,而其衍生物SPAHs的毒性更高。通过对青岛市城阳污水处理厂采样,分析在其SBR/MBBR工艺中16种PAHs及硝基PAHs(NPAHs),甲基PAHs(MPAHs)以及氧基PAHs(OPAHs)的分布与去除。结果表明,16种PAHs及13种SPAHs均有检出,进水中,PAHs与SPAHs的总含量分别为3835.14ng·L-1与6889.46 ng·L-1,其含量远远高于其他地区的污水处理厂。在出水中,PAHs与SPAHs的总含量为1148.18 ng·L-1与1724.57 ng·L-1,去除率分别为70.06%与74.97%,可见SBR/MBBR工艺能有效去除PAHs与SPAHs。水相中PAHs的去除主要是针对低环多环芳烃(LMW-PAHs)的生物降解;而颗粒相中PAHs的去除主要依靠初沉池对LMW-PAHs的吸附沉淀以及生物单元对高环多环芳烃(HMW-PAHs)的生物吸附。对于SPAHs,MPAHs去除效果最好,去除率达89.15%,颗粒吸附以及生物降解是其主要的去除机制;其次是OPAHs,去除率为63.36%,在水相中主要依靠一级处理的颗粒吸附去除,在颗粒相中则主要在二级处理的生物吸附去除;NPAHs的去除率为48.85%,主要在生物池中去除。SPAHs在SBR/MBBR工艺中的去除机制不尽相同,污水处理厂应根据不同处理工段PAHs与SPAHs的分布特征采取相应控制措施,而污泥中富集的PAHs与SPAHs远高于出水的排放量,因此,还应加强污泥中PAHs与SPAHs的管理。     

Use of microbes for cost reduction of metal removal from metals and mining industry waste streams

Acid-rock drainage (ARD) – also known as acid-mine drainage (AMD) – results from the exposure of sulfide minerals, particularly pyritic and pyrrhotitic minerals, to atmospheric oxygen and water. AMD directly impacts tens of thousands of kilometers of streams, lakes and estuaries throughout the world. The impacted water bodies tend to have elevated concentrations of metals in the water column or sediments, and are also stressed by significant inputs of hydrogen ions.There are several conventional treatment technologies available. The most common is chemical precipitation using lime or other basic substances. These systems produce large volumes of wet sludge that often require drying facilities to concentrate the metal hydroxide sludge. Wetland treatment systems have also been used for several decades to treat AMD. Recent developments and improvements have resulted in construction of bioreactors that have a smaller footprint, and treat the metals and acidity more effectively.Many studies have demonstrated that the primary removal mechanisms for the metals are sulphate-reducing bacteria (SRB). These microbes facilitate the conversion of sulphate to sulphide. The sulphides react with metals to precipitate them as metal sulfides, many of which are stable in the anaerobic conditions of the treatment system.Plants have been shown to remove metals by uptake or oxidative precipitation near the roots. Plants seem to account for only a small percentage of the metal removal capacity of the wetland treatment systems. Adsorption of metals to the organic substrates of the treatment systems can result in metal removal, but adsorption capacity is saturated in short periods of time.High oxygen, low pH waters often enter the treatment systems. The SRB are obligate anaerobes which prefer conditions between pH 5 and 8. Thus, the input water characteristics could impact the efficiency and life expectancy of the treatment systems. The most important characteristic of input waters seems to be pH. Low oxygen of the influent waters did not enhance treatment capabilities. Low pH waters do reduce the capacity of the treatment systems to treat metals effectively.Oxyanions such as chromate and arsenate can be removed using the wetland treatment system (passive bioreactor) technology. Arsenic is removed as an arsenic sulfide compound and chromate is reduced to Cr(III) and precipitated as a hydroxide.The passive bioreactor – wetland treatment system – offers a less expensive alternative to the conventional chemical precipitation technologies. There still are problems of system hydraulics and useful life to be addressed.     

海南省集约化种植园中谷物、蔬菜和水果中重金属累积程度及健康风险

集约化种植园中植物有害元素的累积会危及人类健康.本研究共采集海南省典型集约化种植园中谷物、蔬菜和水果样品673份.分析了7种重金属（Cu、Pb、Zn、Cr、Cd、As和Hg）的分布特征,并采用单因子指数和内梅罗指数进行污染物评价.同时,结合中国营养学会推荐的日常膳食摄入量,分析重金属的膳食暴露风险.结果表明,673件农作物的Cu、As和Hg含量均低于国家食品限量标准,Pb、Zn、Cr和Cd的超标率分别为2.67%、3.71%、2.53%和3.71%.6类农作物的重金属综合污染程度表现为：叶类蔬菜 > 薯类 > 非叶类蔬菜类 > 豆类 > 水果 > 谷类.其中,叶类蔬菜中Cr的风险系数（HQ）显著高于其它类型农作物,并且大于1,表明通过叶类蔬菜摄入重金属具有潜在健康风险.薯类、非叶菜蔬菜类、豆类、水果类和谷类农作物的危害指数（HI）较低,表明这几类农作物更适合集约化生产模式.     

污水处理中菌藻共生系统去除污染物机理及其应用进展

菌藻共生系统不仅能够吸收空气中的CO_2,高效去除污水中的氮磷营养物质,而且能够有效去除重金属、抗生素等,因而在污水处理领域日益受到广泛的关注.本文从菌藻之间相互作用关系出发,介绍了用于污水处理时藻类选择的依据,及在污水处理中对N、P营养物质、抗生素、重金属等污染物的去除机理,综述了菌藻系统在污水处理中的应用进展,以期为菌藻共生系统在污水处理中的推广应用提供参考.     

Quantifying the quality loss and resource efficiency of recycling by means of exergy analysis

Contaminants cause a decrease in the quality of materials with each recycling step. These quality losses should be minimized to increase the sustainability of resources use. Quality losses cannot be measured using weight-based recovery definitions alone, as the quality degradation cannot be translated by mass measures. Therefore, a better measure of the efficiency of resource use is investigated in the present work. Exergy is a measure of the quality of the energy and of resources in systems. The exergy losses are a thermodynamic measure of exhaustion and thus, of the quality losses in the resource systems. We describe a method to calculate the exergy content and exergy losses of metals during recovery and recycling of a concept car. The exergy losses attributed to recycling (the pollution with other metals) and the consequent need for dilution can be used as indicators of the quality loss of materials and of the efficiency of resource use in product systems.     

活性污泥工艺对重金属的去除及微生物的抵抗机制

活性污泥工艺通常被用于污水厂的污染物降解和有机物稳定，但同时它还能去除重金属，当重金属的浓度需从10—100mg／L处理到＜1mg／L以下时，其更显得有效和经济。许多重金属可被活性污泥去除，去除率取决于操作条件及其物理，化学和生物的影响因子等。活性污泥细菌产生的胞外多聚糖为聚合物提供了吸附源，并在絮疑沉淀中起重要作用。不同的金属和不同的金属价态在多聚糖上的吸收结合位点不同，导致重金属去除率各不相同。在各种不同规模的活性污泥处理单元中，Fe、Cu、Cr、Pb和Zn有较高的去除率，而Ni、Mn相对较低。金属离子的存在能促使基因产生抗金属毒性的酶，对大多数重金属的抵御属于质粒编码系统，抗重金属的微生物在环境核复中将有诱人的应用前景。     

Hydrogen storage methods

Hydrogen exhibits the highest heating value per mass of all chemical fuels. Furthermore, hydrogen is regenerative and environmentally friendly. There are two reasons why hydrogen is not the major fuel of todays energy consumption. First of all, hydrogen is just an energy carrier. And, although it is the most abundant element in the universe, it has to be produced, since on earth it only occurs in the form of water and hydrocarbons. This implies that we have to pay for the energy, which results in a difficult economic dilemma because ever since the industrial revolution we have become used to consuming energy for free. The second difficulty with hydrogen as an energy carrier is its low critical temperature of 33 K (i.e. hydrogen is a gas at ambient temperature). For mobile and in many cases also for stationary applications the volumetric and gravimetric density of hydrogen in a storage material is crucial. Hydrogen can be stored using six different methods and phenomena: (1) high-pressure gas cylinders (up to 800 bar), (2) liquid hydrogen in cryogenic tanks (at 21 K), (3) adsorbed hydrogen on materials with a large specific surface area (at T<100 K), (4) absorbed on interstitial sites in a host metal (at ambient pressure and temperature), (5) chemically bonded in covalent and ionic compounds (at ambient pressure), or (6) through oxidation of reactive metals, e.g. Li, Na, Mg, Al, Zn with water. The most common storage systems are high-pressure gas cylinders with a maximum pressure of 20 MPa (200 bar). New lightweight composite cylinders have been developed which are able to withstand pressures up to 80 MPa (800 bar) and therefore the hydrogen gas can reach a volumetric density of 36 kg·m^–3, approximately half as much as in its liquid state. Liquid hydrogen is stored in cryogenic tanks at 21.2 K and ambient pressure. Due to the low critical temperature of hydrogen (33 K), liquid hydrogen can only be stored in open systems. The volumetric density of liquid hydrogen is 70.8 kg·m^–3, and large volumes, where the thermal losses are small, can cause hydrogen to reach a system mass ratio close to one. The highest volumetric densities of hydrogen are found in metal hydrides. Many metals and alloys are capable of reversibly absorbing large amounts of hydrogen. Charging can be done using molecular hydrogen gas or hydrogen atoms from an electrolyte. The group one, two and three light metals (e.g. Li, Mg, B, Al) can combine with hydrogen to form a large variety of metal–hydrogen complexes. These are especially interesting because of their light weight and because of the number of hydrogen atoms per metal atom, which is two in many cases. Hydrogen can also be stored indirectly in reactive metals such as Li, Na, Al or Zn. These metals easily react with water to the corresponding hydroxide and liberate the hydrogen from the water. Since water is the product of the combustion of hydrogen with either oxygen or air, it can be recycled in a closed loop and react with the metal. Finally, the metal hydroxides can be thermally reduced to metals in a solar furnace. This paper reviews the various storage methods for hydrogen and highlights their potential for improvement and their physical limitations.     

Toxic metals in sewage sludge-amended soils: has promotion of beneficial use discounted the risks?

Land application of contaminated waste products has been defended as beneficial use by some scientists and regulators, based on the premise that the behavior of any toxins accumulated in soils from this practice is reasonably well understood and will not have detrimental agronomic or environmental impacts into the foreseeable future. In this review, I use the case of toxic metals in sewage sludges applied to agricultural land to illustrate that metal behavior in soils and plant uptake is difficult to generalize because it is strongly dependent on the nature of the metal, sludge, soil properties and crop. Nevertheless, permitted agricultural loadings of toxic metals from sewage sludges are typically regulated using the sole criterion of total metal loading or concentrations in soils. Several critical generalizing assumptions about the behavior of sludge-borne metals in soil-crop systems, built into the US EPA risk assessment for metals, have tended to underestimate risks and are shown not to be well justified by published research. It is argued that, in the absence of a basic understanding of metal behavior in each specific situation, a more precautionary approach to toxic metal additions to soils is warranted.     

透水铺装类型对径流重金属去除效能的影响机制

研究了不同类型透水铺装系统对径流重金属的去除效能和机制。在实验室搭建了3种典型透水铺装系统（陶瓷透水砖、透水沥青和透水混凝土）,研究了其对5种常见径流重金属（Cu、Zn、Cd、Mn、Ni）的去除效能和机制,并分析了不同降雨重现期（2,3,5年）对透水铺装系统去除径流重金属的影响。结果表明:3种透水铺装系统对5种径流重金属都有较好去除效果,其中陶瓷透水砖的去除效果最好,且去除效果最稳定。比较而言,陶瓷透水砖与透水沥青能够在短时间内降低重金属的浓度,透水混凝土达到吸附点位的速度较慢并有一定波动,特别是在不同降雨重现期下波动更加明显。在不同重现期下,各设施表现出不同性能,影响程度为2年＞5年＞3年,即整体在重现期为3年的降雨条件下有着较为优异且较为稳定的去除性能,而过大或过小的流量都会使透水铺装去除重金属的性能有所降低。     

近海潮间带水体及沉积物中重金属的含量及分布特征

利用ICP-MS分析技术,系统测定了天津沿海潮间带表层海水、悬浮物、沉积物及沉积物间隙水中13种重金属元素的含量.结果表明,不同介质中重金属总含量和个体含量差别较大,最大相差4～7个数量级(水和悬浮物中).在相同介质中,各采样点重金属总含量差别不大,变异系数小于30%,个体重金属浓度除间隙水中差别较大外,变异系数均小于50%.潮间带海水中溶解态重金属含量均值为41.2μg·L^-1,原水、沉积物间隙水、悬浮物和沉积物中重金属含量均值分别为62.7μg·L^-1、112.7μg·L^-1、345.0mg·kg^-1和262.3 mg·kg^-1.潮间带各介质中重金属构成有显著差别,典型重金属元素Zn、Cu、Pb和Cr在原水和过滤水中约占40%～50%,而在悬浮物、沉积物及其间隙水中约占到50%～80%.潮间带水体、悬浮物、沉积物与滨岸土壤中重金属元素组成和分布模式的相似性表明其污染来源为陆源污染物.对悬浮物和沉积物中重金属含量与有机质含量的相关分析结果显示二者间相关性较弱,但各重金属含量之间有显著的相关关系,说明它们有相似的地球化学行为.     

两类典型重金属土壤污染研究

对贵州水城矿务局周围煤矸石污染土壤和Pb、Zn冶炼场污染土壤的重金属污染状况进行了研究和评估。研究结果表明：煤矸石风化形成的土壤有一定的重金属污染，污染程度取决于煤矸石的组成。Pb、Zn土法冶炼造成土地严重污染，在污染土壤中种植的农作物中重金属含量严重超标。重金属在土豆不同部位富集程度各不相同，而且Pb-Cd、PbZn、Zn-Cd在植物体内具有较高的正相性。