城市污泥的重金属生物活性及其控制

随着土壤法规的加强，城市污泥中的重金属严重影响着污泥的处理、处置。介绍了污泥中重金属的分配和化学形态，以及迄今为止几种主要的控制方法。     

城市污水处理厂的污泥农用对土壤的重金属影响

污泥农用是城市污水处理厂污泥资源化利用的有效途径，但污泥中的重金属元素含量高，可能成为环境中的一种安全隐患。重金属对环境的危害不仅与其总量有关，更大程度上由其形态分布所决定。实验研究了污泥农用所引入的重金属对土壤重金属总量及其形态的影响，研究结果表明，污泥农用虽然明显增加了土壤中的重金属总量，但重金属在土壤中的活性却受到了抑制，从而降低了重金属通过食物链危害人类健康的风险。     

污泥中重金属的去除及回收试验

论述了利用离子交换技术循环使用柠檬酸去除污泥中重金属,并置换回收重金属的适宜工艺条件.经柠檬酸处理后,污泥中90%以上的重金属被去除;柠檬酸处理液中的重金属用离子交换法回收,考察了树脂种类、流速、操作方式等因素对离子交换、再生效果的影响;在适宜工艺条件下,重金属的交换率均为100%,而洗脱率均接近90%;柠檬酸及离子交换树脂循环使用,重金属也得到回收,降低了处理成本.     

城市污泥的重金属生物活性及其控制

随着土壤法规的加强 ,城市污泥中的重金属严重影响着污泥的处理、处置。介绍了污泥中重金属的分配和化学形态 ,以及迄今为止几种主要的控制方法     

畜禽养殖废水生物处理剩余污泥臭氧减量过程中的重金属释放

采用臭氧氧化污泥减量法对畜禽养殖废水SBR中的剩余污泥进行处理。当臭氧反应时间控制在30min时，污泥的溶解比例在30％左右（以MLSS计）。上清液中一定量的SCOD溶出可为生物处理单元提供充足的碳源，同时在上清液中，TN、TP及水相重金属浓度增加有限，臭氧氧化后的污泥液回流污水处理系统后造成的N、P处理负荷较小，重金属对污泥微生物的活性抑制风险较低。若继续延长臭氧的反应时间，上清液SCOD、TN、TP以及重金属cu、Pb的释放速率明显增加，同时上清液的C／N降低，臭氧化后的污泥液回流反而不利于生物单元的脱氮处理。综合考虑TN、TP及水相重金属浓度增加的危害性，臭氧反应时间应控制在30min，臭氧实际投加量应为123．1mg O3／gSS。     

去除污泥中重金属铬的生物淋滤反应器设计与应用

用微生物方法去除污泥中重金属（生物淋滤法）是近年来发展的新技术，探索工程化的条件有重要的应用价值。设计了一套容积为1m^3的生物淋滤反应器，由生物淋滤池、搅拌器、曝气器和空气压缩机等构成。其中，搅拌叶轮由平叶桨和斜叶桨组合而成。利用制革污泥进行了半连续的生物淋滤试验，结果表明，在反应器中污泥与菌体和营养物质能充分混匀，经过2-5d的处理，污泥pH持续下降到2．0以下，污泥中铬的溶出率达90％-99．5％。     

蚯蚓直接处理城市剩余污泥的研究

以城市剩余污泥为饲料，根据蚯蚓的繁殖、生长时间，定时引出成蚓换料连续饲养，并改变留在原泥中蚓卵的生存环境来控制卵的发育之蚯蚓养殖方法，并对城市剩余污泥直接饲养蚯蚓的可行性及其重金属转移规律进行研究。结果表明，城市剩余污泥直接饲养蚯蚓是可行的；饲养过程中蚯蚓体内的重金属浓度随着饲养时间而上升，至4个月左右，蚯蚓体内重金属浓度达到极限，且该养殖法具有蚯蚓产量低，对蚯蚓具有易于处理和处置的优点。     

热解污泥生物炭化学组成及环境效应研究进展

污泥是生物法处理市政污水、工业废水产生的副产物,产量大,且处理不当会造成生态污染。用污泥制备污泥生物炭,既能实现污泥资源化利用又能减少环境污染。对目前热解污泥生物炭制备和施用过程中产生的环境效应进行综述,着重讨论了热解污泥制备污泥生物炭过程中的元素(碳、氢、氧、氮、硫等)转化、污泥生物炭中重金属形态、吸附性质及土壤施用情况。系统地分析污泥生物炭从制备到施用过程的环境效应,有利于对其实际应用进行全面的环境风险评估。     

Fenton氧化联合人工湿地处理污泥中的重金属

针对单独应用Fenton氧化技术处理污泥的不足以及人工湿地在处理污水污泥方面的优势,以污水处理厂污泥浓缩池中含重金属污泥为对象,研究其依次经过Fenton氧化和人工湿地处理后重金属的去除效果及形态变化,以及污泥pH、TN和TP的变化情况。结果表明,Fenton氧化提高了污泥重金属的生物有效性,并促进了人工湿地对重金属的去除。Fenton氧化污泥经人工湿地处理后,Cu、Zn、Ni和Mn的去除率分别为67.2%、79.7%、37.0%和17.0%,与对照相比重金属的平均去除率提高了27.5%。经人工湿地处理后Fenton氧化污泥和原污泥重金属的生物有效性均降低。Fenton氧化污泥pH为4.4~4.6,经人工湿地处理后为6.2~7.1。人工湿地对Fenton氧化污泥和原污泥中TN的影响较小,而对TP表现出较高的去除率,2系统TP的去除率分别为51.1%和45.5%。     

畜禽养殖废水生物处理剩余污泥臭氧减量过程中的重金属释放简

采用臭氧氧化污泥减量法对畜禽养殖废水SBR中的剩余污泥进行处理。当臭氧反应时间控制在30 min时，污泥的溶解比例在30%左右（以 MLSS计）。上清液中一定量的SCOD溶出可为生物处理单元提供充足的碳源，同时在上清液中，TN、TP及水相重金属浓度增加有限，臭氧氧化后的污泥液回流污水处理系统后造成的N、P处理负荷较小，重金属对污泥微生物的活性抑制风险较低。若继续延长臭氧的反应时间，上清液SCOD、TN、TP以及重金属Cu、Pb的释放速率明显增加，同时上清液的C/N降低，臭氧化后的污泥液回流反而不利于生物单元的脱氮处理。综合考虑TN、TP及水相重金属浓度增加的危害性，臭氧反应时间应控制在30 min，臭氧实际投加量应为123.1 mg O₃/g SS。     

国内外重金属废水处理新技术的研究进展

有毒重金属对环境的严重威胁正逐渐成为全球性问题，着重综述了近年来国内外重金属污染处理技术的研究与进展。除了改进传统的化学、物理方法外，各种廉价高吸附性能的吸附剂、新型可选择性重金属捕集剂都是研究的焦点。特别是随着生物技术的发展，利用功能菌和植物处理含重金属污染已取得相当成效，并在工业上进行了实际应用。研究和发展新型天然吸附剂、重金属捕集剂和生物技术，加强多种技术的综合应用，是治理重金属污染的有效途径。     

农业生产面源污染控制探讨

就农业面源污染对农业可持续发展的影响，以及造成面源污染的原因进行了分析，从观念上、政策上、技术上对农业面源朽染控制做了一些探讨，以促进农村水环境保护和农业的可持续发展。     

常用城市污水再生处理工艺净化效果比较分析

以城市污水回用为目的,对常规混凝-沉淀-过滤工艺、臭氧生物活性炭和直接超滤等深度处理技术处理城市污水处理厂二级出水的效果进行了试验研究,对各种工艺的去除效果进行了评价。     

Decontamination of produced water containing petroleum hydrocarbons by electrochemical methods: a minireview

Produced water (PW) is the largest waste stream generated in oil and gas industries. The drilling and extraction operations that are aimed to maximize the production of oil may be counterbalanced by the huge production of contaminated water (called PW) with pollutants, such as heavy metals, dissolved/suspended solids, and organic compounds. PW is conventionally treated through different physical, chemical, and biological methods. In offshore platforms, because of space constraints, compact physical and chemical systems are used. However, major research efforts are being developed with innovative technologies for treating PW in order to comply with reuse and discharge limits. Among them, electrochemical technologies have been proposed as a promising alternative for the treatment of this kind of wastewaters. Then, this paper presents a minireview of efficient electrochemical technologies used until now for treating PW generated by petrochemical industry.     

A review on management of chrome-tanned leather shavings: a holistic paradigm to combat the environmental issues

Raw hide/skins come to the tanners as a by-product of meat industry which is converted into value-added leather as product for fashion market. Leather manufacturing is a chemical process of natural biological matrix. It employs a huge quantity of water and inorganic and organic chemicals for processing and thereby discharges solid and liquid wastes into the environment. One of the potential solid wastes generated from leather industry is chrome-tanned leather shavings (CTLSs), and its disposal is increasingly becoming a huge challenge on disposal to tanners due to presence of heavy metal chromium. Hence, finding a sustainable solution to the CTLS disposal problem is a prime challenge for global tanners and researchers. This paper aims to the deeper review of various disposal methods on CTLS such as protein, chromium, and energy recovery processes and its utilization methodologies. Sustainable technologies have been developed to overcome CTLS solid wastes emanating from leather processing operations. Further, this review paper brings a broader classification of developed methodologies for treatment of CTLSs.     

Structure of inorganic and carbonaceous particles emitted from heavy oil combustion

The combustion of heavy fuel oil for power generation is a great source of carbonaceous and inorganic particle emissions, even though the combustion technologies and their efficiency are improving. The information about the size distribution function of the particles originated by trace metals present into the fuels is not adequate. In this paper, we focused our attention on the larger distribution mode of both the carbonaceous and metallic particles. Isokinetic sampling was performed at the exhausts of two typical heavy oil flames and the samples were size-segregated by mean of an 8-stages Andersen impactor. Further investigation performed on the samples using electronic microscopy coupled with X-ray analysis (EDX) evidenced the presence of solid spherical particles, called plerosphere(1) as analogy with cenosphere, with typical dimensions ranging between 200 nm and 2-3 microm, whose atomic composition contains a large amount of the trace metals present in the parent oils (Fe, V, Ni, etc). EDX analyses revealed that the metal concentration increases as the plerosphere dimension decreases.     

Effect of different types of elemental sulfur on bioleaching of heavy metals from contaminated sediments

The application of two different types of elemental sulfur (S0) was studied to evaluate the efficiency on bioleaching of heavy metals from contaminated sediments. Bioleaching tests were performed in suspension and in the solid-bed with a heavy metal contaminated sediment using commercial sulfur powder (technical sulfur) or a microbially produced sulfur waste (biological sulfur) as substrate for the indigenous sulfur-oxidizing bacteria and thus as acid source. Generally, using biological sulfur during suspension leaching yielded in considerably better results than technical sulfur. The equilibrium in acidification, sulfur oxidation and metal solubilization was reached already after 10-14 d of leaching depending upon the amount of sulfur added. The metal removal after 28 d of leaching was higher when biological sulfur was used. The biological sulfur added was oxidized with high rate, and no residual S0 was detectable in the sediment samples after leaching. The observed effects are attributable to the hydrophilic properties of the biologically produced sulfur particles resulting in an increased bioavailability for the Acidithiobacilli. In column experiments only poor effects on the kinetics of the leaching parameters were observed replacing technical sulfur by biological sulfur, and the overall metal removal was almost the same for both types of S0. Therefore, under the conditions of solid-bed leaching the rate of sulfur oxidation and metal solubilization is more strongly affected by transport phenomena than by microbial conversion processes attributed to different physicochemical properties of the sulfur sources. The results indicate that the application of biological sulfur provides a suitable means for improving the efficiency of suspension leaching treatments by shortening the leaching time. Solid-bed leaching treatments may benefit from the reuse of biological sulfur by reducing the costs for material and operating.     

Biomonitoring of heavy metals in the Western European Rivers Rhine and Meuse using the freshwater mussel Dreissena polymorpha

Since 1976, active and passive biological monitoring programs using the freshwater mussel Dreissena polymorpha have been carried out to study trends in the bioavailability of heavy metals in the rivers Rhine and Meuse. The Cd concentration in mussels exposed in the river Rhine has decreased from 74 mg kg(-1) in 1976 to 1.5 mg kg(-1) in 1988. In the river Meuse, however, the Cd concentration in Dreissena polymorpha has increased from 6 mg/kg (-1) to 22 mg kg(-1). Cu concentrations in mussels have not changed. Comparison of heavy metal concentrations in mussels from Lake Heerhugowaard, Lake Markermeer, Lake Maarsseveen and the river Dieze demonstrated that background concentrations for Cu, Zn, Cd and Pb in Dreissena polymorpha are about 12, 110, 1 and 0.5 mg kg(-1), respectively. Mussels from these four locations showed seasonal variation in heavy metal concentrations. This may be caused by both changes in the bioavailability of the metals and by the annual growth and reproductive cycle of the mussels. Therefore, one should take care that animals are collected at the same location and in the same section in long-term active biological monitoring programs.     

Influence of soil properties on heavy metal sequestration by biochar amendment: 2. Copper desorption isotherms

Contaminant desorption constrains the long-term effectiveness of remediation technologies, and is strongly influenced by dynamic non-equilibrium states of environmental and biological media. Information is currently lacking in the influence of biochar and activated carbon amendments on desorption of heavy metal contaminants from soil components. In this study, copper sorption-desorption isotherms were obtained for clay-rich, alkaline San Joaquin soil with significant heavy metal sorption capacity, and eroded, acidic Norfolk sandy loam soil having low capacity to retain copper. Acidic pecan shell-derived activated carbon and basic broiler litter biochar were employed in desorption experiments designed to address both leaching by rainfall and toxicity characteristics. For desorption in synthetic rain water, broiler litter biochar amendment diminished sorption-desorption hysteresis. In acetate buffer (pH 4.9), significant copper leaching was observed, unless acidic activated carbon (pH_pzc = 3.07) was present. Trends observed in soluble phosphorus and zinc concentrations for sorption and desorption equilibria suggested acid dissolution of particulate phases that can result in a concurrent release of copper and other sorbed elements. In contrast, sulfur and potassium became depleted as a result of supernatant replacements only when amended carbon (broiler litter biochar) or soil (San Joaquin) contained appreciable amounts. A positive correlation was observed between the equilibrium aluminum concentration and initial copper concentration in soils amended with acidic activated carbon but not basic biochar, suggesting the importance of cation exchange mechanism, while dissolution of aluminum oxides cannot be ruled out.     

生物脱氮新技术研究进展

本文对短程硝化反硝化、同时硝化反硝化及厌氧氨氧化等生物脱氮新技术的研究和开发进展进行了简单的综述和讨论 ,并指出了这些新技术的特点和研究开发应用的前景。