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污泥是由污水处理过程中形成的沉淀物,具有含水率高、有机物含量高、重金属含量高等特点,其中重金属污染控制一直是污泥处理处置的难点。生物浸出技术具有耗酸少,运行成本低,重金属去除率高,无二次污染等优点被广泛应用。本文论述了生物浸出技术的浸出菌种,影响因素,研究现状及应用,展望了生物浸出技术研究的重点。 相似文献
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污水污泥页岩烧结制品的重金属固化与水环境浸出稳定性 总被引:3,自引:0,他引:3
提高重金属固化程度与浸出稳定性是含重金属污水污泥处置和利用的前提。采用污水污泥并模拟提高其重金属Cr、Cu、Pb的含量,与页岩混合制备烧结砖和陶粒制品,研究重金属在页岩制品高温烧制过程中的固化率以及制品中重金属的水环境浸出稳定性,通过X射线衍射和扫描电子显微镜分析含重金属矿物的赋存形态和页岩制品微观形貌对重金属固化与浸出稳定性影响。与相同条件下焚烧纯污水污泥相比,重金属在页岩制品烧制过程中固化率明显提高,浸出毒性明显降低,重金属在页岩制品中易形成稳定的尖晶石型矿物以及页岩制品所具有的致密微观结构;相比烧结砖,陶粒中重金属固化程度和浸出稳定性更高,因为陶粒在更高温度下有利于尖晶石型矿物和致密结构形成。 相似文献
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结合目前有色冶金工业上普遍采用的石灰铁盐法工艺特点,首次采用改进的BCR连续提取法与毒性浸出实验相结合的方法对铜污泥(中和渣与铁砷渣污泥)的重金属形态分布与浸出毒性进行了系统的研究。结果表明:采用改进的BCR方法对铜冶炼污泥重金属元素形态进行提取,形态提取具有较高的回收率;As、Zn、Pb与Cd为中和渣与铁砷渣污泥中主要的重金属元素(质量含量As>Zn>Pb>Cd),其中中和渣含As高达58 566 mg/kg(折合5.85%),铁砷渣含As为12 582 mg/kg(折合1.26%);两种重金属形态分布差异主要体现在As的形态分布上,铁砷渣污泥中重金属稳定性较好,特别是砷的稳定性较中和渣高;中和渣污泥中,As主要以弱酸态形式存在(占68.01%),Zn、Pb与Cd主要以残渣态存在;铁砷渣污泥中,As、Zn、Pb与Cd主要以残渣态存在,其中残渣态As占59.21%;浸出毒性结果显示两种污泥中砷的浸出毒性都远远超过国标GB 5085.3-2007规定值,因此铜冶炼厂污泥属于含高砷危险废弃物,而以弱酸态As为主的中和渣污泥浸出毒性较高,而主要以残渣态As存在的铁砷渣污泥浸出毒性较低。 相似文献
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探讨了在烧结制备红土砖和黏土砖的过程中掺入不超过10%(质量分数)的电镀污泥对其物理力学性能的影响,并评估了其重金属长期浸出风险。结果表明,掺入10%电镀污泥的烧结砖质量损失最大达到11.23%,线性收缩率最大达到-5.7%,吸水率最大达到11.47%,孔隙率最大达到22%,抗压强度最大达到15.66 MPa,皆满足国家相关标准要求;黏土砖的各项性能优于红土砖。浸出风险研究表明,总铜、总锌、总铬、总镍的最大浸出浓度分别为0.45、0.92、0.13和0.19 mg/L,远低于危险废物鉴定标准,表明掺入电镀污泥的烧结砖不是危险废物。 相似文献
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污泥焚烧底灰的处理处置与资源化利用是污泥焚烧过程中必须解决的难题。该文通过对两种不同的污泥焚烧底灰的粒径、抗剪、压缩固结性、渗透性以及重金属含量等理化性质进行了研究,并将其与原生污泥性质进行对比,分析焚烧处理对污泥理化性质的影响,并进一步根据焚烧底灰性质,探索其再利用途径。结果表明污泥焚烧底灰属于砂土,且抗剪强度较污泥焚烧前有明显增大,可达76.23~80.03kPa;重金属含量有所超标,但重金属浸出量均小于相应标准限定值,可进行路基材料、cO2捕集、填海造陆等再利用。 相似文献
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This research evaluated the use of sewage sludge and refuse incineration bottom ash to replace calcium sulfoaluminate cement(CS(_)A) in making controlled low-strength material(CLSM).Various properties of CLSM mixtures were characterized in terms of unconfined compressive strength,microstructure and leachability.It was found that the strength of tested CLSM mixtures ranged from 3.6 to 9.0 MPa,over the upper excavatable limit of 2.1 MPa.The micro-structural analysis revealed that sewage sludge and bottom ash were crystallochemically in-corporated within CLSM systems by forming the needle-like ettringite(C3A?3CS(_)?H32) with exiguous tubers via the typical Pozzolanic Reaction,leading to a dense and low-porosity microstructure.Furthermore,the toxicity charac-teristic leaching procedure evidenced that the cumulative leachable metals in the leachate were much below the regulatory thresholds.The potential for using sewage sludge and bottom ash in CLSM making was thus confirmed. 相似文献
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医疗垃圾焚烧飞灰中重金属的蒸发特性 总被引:1,自引:0,他引:1
利用管式高温炉研究了医疗垃圾焚烧飞灰中重金属的蒸发特性,以确定飞灰中重金属的有效热分离参数. 结果表明,停留时间20与60 min时的重金属蒸发率差别不大,其影响程度取决于温度;布袋飞灰中高含量Cl的存在对重金属的蒸发有促进作用;在1000℃时,飞灰中Pb和Cd的蒸发率已达90%以上;气氛对Zn的蒸发效果影响显著,Zn在1000℃空气气氛下蒸发率仅为67%,但在N2气氛下蒸发率高达92%;若考虑Cd, Pb, Zn等挥发性重金属有效分离和二噁英分解两方面的需求,医疗垃圾焚烧飞灰的最低热处理温度宜控制在1000℃左右. 相似文献
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以污泥焚烧灰为原料,通过酸处理和加碱煅烧预处理后,采用水热法合成了NaSOD型沸石,并对其进行了表征和性能测定。结果表明:酸处理可显著提高焚烧灰中硅铝成分的含量,加碱煅烧能够有效激活存在于石英等晶体中的硅铝元素;酸预处理的最佳pH为1,此时SiO2和A1舢含量的百分比之和可达77.65%,比焚烧灰原料高出22.17%;最佳煅烧碱灰比为3:2,最佳煅烧温度为700℃。对合成样品的X射线衍射(XRD)、扫描电镜(SEM)以及傅里叶红外光谱(Fr—IR)表征结果显示,污泥焚烧灰经过预处理后合成的样品,其结构呈NaSOD型沸石,且结晶完整、晶型单一,晶体形貌为球形笼状结构,合成沸石中自由水的含量高。而未经预处理直接水热合成的样品,结晶度低,且存在大量未被活化的石英晶体。因此,预处理对污泥焚烧灰合成NaSOD型沸石起着至关重要的作用。性能测定的结果显示,经预处理合成的NaSOD型沸石,其阳离子交换容量(CEC)、比表面积和总孔容,相对于焚烧灰原料分别提高了40、78和24倍,而未经预处理直接水热合成的产物则分别只提高了14、30和12倍。这意味着经预处理的合成产物在离子交换、吸附和催化等方面的性能有了很大的提升。 相似文献
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《分离科学与技术》2012,47(12):1910-1920
During sewage sludge incineration phosphorus (P) is retained in the ash in a form not directly available to plants. As P is a sparse resource, it is important to develop techniques for recovery of P from incinerated sewage sludge ashes (ISSA). Heavy metals are concentrated in ISSA and separation of P and heavy metals is required. The present work is an experimental screening of a new combination of acid extraction and electrodialysis–electrodialytic separation (EDS) for simultaneous P recovery and removal of heavy metals. Experiments were conducted with two different ashes; rich in Fe or Al. The separation method was best suited for the Fe-rich ash, where it was possible to separate P into one processing solution, heavy metals (Cu, Zn, Ni, Pb) into another, keeping the ash suspended in a third solution (which though still contained P after 1 week of EDS). For the Al rich ash, the separation was not similarly encouraging. The high release of Al during the extraction influenced the speciation of P and negatively charged P complexes were not prevailing. On the contrary to Al, the Fe containing ash particles were insoluble so Fe did not interfere with P speciation and separation after extraction. 相似文献
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《分离科学与技术》2012,47(16):3393-3405
Abstract There is a great need for heavy metal removal from strongly metal‐polluted sewage sludges. One of the advantages of heavy metal removal from this type of sludge is the possibility of the sludge disposal to landfill with reduced risk of metals being leached to the surface and groundwater. Another advantage is the application of the sludge as soil improver. The use of chemical precipitation to remove dissolved heavy metals from sewage sludge implies a high cost for chemicals. This work shows, for real sewage sludge for the first time that the addition of NaOH as first precipitating agent considerably saves the addition of Na2S, that is one of the most effective metal precipitating agents and also expensive. After solubilization of heavy metals by chemical leaching with previous aeration, the next step was the separation of the sludge solids from the metal‐rich acidic liquid (leachate) by centrifugation and filtration. Afterwards, the filtered leachate was submitted to the application of NaOH and Na2S, separately and in combination, followed by filtration. The results showed that when iron and aluminium are present in the leachate, adsorption and/or coprecipitation of Cr, Pb, and Zn with Fe(OH)3 and Al(OH)3 might occur at increasing pH conditions. The combination of hydroxide and sulfide precipitation was able to promote an effective removal of heavy metals from leachate. Applying NaOH at a pH of 4–5 as a first precipitation step, followed by filtration and further addition of Na2S to the filtered liquid at pH of 7–8 as a second precipitation step, decreased considerably the dosage of the second precipitant (almost 200 times), compared to when it was solely applied. This has practical applications, as the claimed costs drawbacks of H2S addition is considerably reduced by the addition of the less expensive NaOH. The best removal efficiencies obtained were: Pb: ~100%, Cr: 99.9%, Cu: 99.7%, and Zn: 99.9%. 相似文献