市政污泥干化及焚烧处理工艺的分析及建议

市政污泥是城镇污水处理厂的主要副产物,为有效处置和综合利用污泥,对市政污泥现有填埋、堆肥利用、建材利用、干化焚烧四种处置方式进行对比分析,对污泥干化和焚烧是污泥无害化处置的趋势。这种处置方式可将污泥有机物、有害物彻底分解,同时实现重金属离子的高温烧结固化,具有减容、减量、无害化的特征,燃烧后的残渣可进行综合利用,烟气经过处置后满足达标排放标准。通过对市政污泥干化和焚烧主流工艺进行分析对比,期望能够对新建污泥处置厂提供参考。     

污泥再生材料的探讨——以宝鸡市污泥处置为例

污泥中含有大量的有机物、无机矿物质、重金属以及病菌、寄生虫卵等。当前,我国污泥的处置以填埋为主,不仅污染环境,而且也是资源的浪费。由于污泥中特殊的成分,污泥可作为建筑用砖、活性炭等深加工产品的原材料。本文综述了污泥做建筑砖的方法,详述了污泥制作活性炭的方法、特点和研究进展。最后,本文以宝鸡市污泥处置的实例分析,发现在重金属含量达标前提下,污泥作为堆肥可满足宝鸡市1.8%耕地的用肥需求,将宝鸡市焚烧后的污泥灰做建筑用砖,带来的经济收益可降低污泥焚烧厂17%的运营成本,具有可观的经济效益。     

污泥焚烧灰渣中重金属的检测和毒性分析

采用ICP-OES和原子荧光光度计分析了污泥及其焚烧灰渣中重金属的种类和浓度,并对灰渣中重金属的浸出毒性进行分析。结果表明污泥焚烧灰渣中重金属种类多、浓度高,可依据不同重金属的挥发性大小将污泥中重金属划分为极易挥发重金属、易挥发重金属、中等挥发重金属和难挥发重金属四大类,实际污染控制中应重点关注重金属Hg、As、Cd、Pb四种重金属的控制;同时,毒性浸出实验结果表明污泥焚烧之后灰渣中重金属稳定性得到极大提高,可直接进行填埋处理,但做建材使用时仍存在很大的浸出风险。     

电镀重金属污泥的水泥固化处理试验研究

采用水泥固化的方法对电镀重金属污泥进行处理研究。对固化块在不同pH值水溶液中的浸泡试验表明,在水泥与电镀重金属污泥、河沙、活性氧化铝、硅酸钠的质量比为1∶0.8∶0.20∶0.08∶0.06时,水泥固化电镀重金属污泥效果良好。水泥用量应大于电镀重金属污泥量。加入适量的活性氧化铝、硅酸钠等添加剂,可提高固化效果。研究还对固化块的养护条件及几种配比情况下固化块的抗压强度进行了初步试验。     

上海市某污水处理厂污泥重金属特性及主成分分析

对上海市某污水处理厂污泥重金属特性及含量进行分析,为市政污泥可农用性提供初步判断.研究结果表明,该污水处理厂污泥重金属Cu、Zn、Pb、Cd、Cr、Ni含量均值分别为246、591、60.8、1.35、58.6、33.0 mg/kg.主成分分析(PCA)显示,第一主成分(PC1)中重金属Cu、Zn、Pb、Cd、Cr和Ni占主导作用,为污泥主要污染因子,且其值反映重金属的影响力;第二主成分(PC2)反映污泥中有机质与热值.与污泥农用重金属控制标准比较,样品污泥中重金属检测浓度均低于控制浓度限值,表明该污水处理厂污泥具有可农用性潜力.     

生物浸出污泥重金属研究进展

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。     

好氧颗粒污泥的形成及其应用的研究进展

简要论述了好氧颗粒污泥的形成机制,分析了水力剪切力、碳源与有机负荷、p H与游离氨、温度、金属阳离子、沉淀时间等因素对好氧颗粒污泥的形成及性能的影响,重点阐述了好氧颗粒污泥在同步脱氮除磷、去除高浓度有毒有机物和去除重金属方面的应用研究,并对好氧颗粒污泥的研究方向进行展望。     

造纸污泥与煤混烧过程中污染物的迁移特性

选择宁夏吴忠某造纸厂污泥为研究对象,将其与宁夏本地煤炭进行混合,用热重-质谱仪分析了室温~1 000℃时,污泥与煤混烧特性及混烧过程中NOx和SOx污染物的排放,并用原子吸收分光光度计和原子荧光光谱仪分别研究了燃烧前后样品中重金属Pb,Cr,Cu,Zn,Ni,Mn,Hg和As的迁移.结果表明,造纸厂污泥与煤混烧后,燃烧特性良好,并且燃烧后的灰渣中重金属含量符合GB 4284-1984,不会对水土造成二次污染;燃烧过程中一部分重金属迁移到烟气中去.因此,应采用吸附及除尘结合的方式对烟气进行处理,避免污泥资源化处理过程中对大气的污染.     

油泥焚烧过程重金属迁移转化特性研究进展

焚烧法是油田含油污泥主要处理方法之一,含油污泥焚烧过程中重金属的排放问题成为研究重点。针对含油污泥以及含油污泥中的重金属来源与危害进行了概述,同时综述了含油污泥性质、重金属性质、焚烧温度、停留时间、焚烧气氛以及固体添加剂六个影响因素,对含油污泥焚烧过程重金属迁移转化规律的影响。     

利用TG-FTIR系统研究氧气浓度对污泥干化焚烧的影响

利用TG-FTIR系统,分析了污泥在升温过程中的质量变化,以及氧气浓度对失重过程和气体释放的影响.研究结果表明:污泥的失重过程可分为四个阶段,即水分蒸发-有机质挥发和分解-有机质分解和燃烧-碳燃烧;氧气浓度越大,有机质挥发和分解速率越大;本次实验中氧气浓度为17.65％的气氛下,污泥中有机质能够完全分解或燃烧,释放的气体量最大;在氧气浓度为6.67％和12.65％的气氛下,污泥中的部分有机物并不能完全分解和燃烧.     

Evaluation of pyrolysis residue of oil sludge for recycling as bed material

Pyrolysis is an appealing technique to convert oil sludge into valuable products such as gaseous and liquid fuels, however, there is lack of research on the use of solid residue after sludge pyrolysis. This work investigated the possibility of recycling solid residue as bed material for the pyrolysis process. The thermogravimetric analysis of the raw sludge in both the pyrolysis condition and combustion condition found that part of the heavy organic compounds in the oil sludge was difficult to recover by pyrolysis, though could be combusted easily in the presence of oxygen. Therefore, by leaving the heavy compound in the solid residue, the solid residue can be self-heated by combustion and cycled to the pyrolysis process to enhance heat transfer and catalysis. A series of pyrolysis residues at varies temperatures and holding times were collected after pyrolyzing oil sludge in this study. To examine whether there is sufficient potential heat remaining in the pyrolytic residue, the residue was further investigated by FTIR, proximate, ultimate analysis, and TGA in air to study the combustion characteristics and combustion kinetics. Higher pyrolysis temperature and longer pyrolysis time resulted in more ash and fixed carbon in the residue, though less volatile matter. Residue pyrolyzed at a lower temperature was easier to combust and showed lower combustion activation energy, though the recovery of organic fuel was not significant. Pyrolysis time had very minor effect on the solid residue combustion behaviour. It is more appropriate to control the residue property by governing the pyrolysis temperature.     

城市生活污泥性质的研究

通过对猎德污水处理厂污泥成分的研究表明猎德污水处理厂污泥性质稳定,其有机质及总养分含量属于中等,并且pH指标与卫生学指标良好,重金属含量相对较低,符合《城镇污水处理厂污泥处置农用泥质》标准,是良好的农用泥质。     

Compost mulch effects on soil fertility, nutritional status and performance of grapevine

Two composts were tested as mulching materials in a vineyard: one was a sewage sludge and bark compost with a low heavy metal content, the other was a municipal solid waste compost with a higher concentration of metals. Both compost mulches increased organic matter content, available phosphorous and exchangeable potassium of soil and improved the porosity and water retention capacity of the soil. They also reduced soil temperature fluctuations, reduced evaporation of soil water, and influenced the levels of some nutrients measured in leaf samples. The data obtained show that the nutrients uptake was more influenced by the physical conditions of the soil (temperature, moisture) than by the availability of nutrients in the soil. The sewage sludge and bark compost did not cause any significant increase in heavy metal levels in soil and plants. In contrast, the municipal solid waste compost led to a notable accumulation of metals in the soil, in the vegetation and in the musts. Both the compost mulch materials had considerable advantages for the soil management on the grapevine rows, by reducing chemical weed control and allowing for the substitution of chemical fertilisers with no loss in vigour, yield or quality of musts.     

热重-红外联用分析制革污泥的燃烧特性

利用TG-FTIR对制革污泥的燃烧特性和燃烧过程气体释放情况进行了研究。研究发现,制革污泥挥发分和灰分含量较高,固定碳含量低、热值低。不同升温速率下,制革污泥的燃烧在800℃时已经比较充分,随着升温速率的增加,制革污泥碳燃烧的失重速率和峰值温度有所增加。运用Ozawa法进行活化能计算表明,制革污泥燃烧所需活化能随着反应程度的深入而增加。制革污泥的挥发分燃烧阶段符合三维扩散的Z-L-T方程反应模型,固定碳燃烧阶段符合自催化反应的P-T方程反应模型,且制革污泥在不同升温速率下燃烧动力学参数存在动力学补偿效应。TG-FTIR分析表明,不同升温速率对气体析出基本特征没有影响,在低温阶段,制革污泥的燃烧产物中有少量的有机酸组分析出。     

重质有机质热解过程中挥发物的产出与逸出气体分析研究进展

煤、重质油、生物质等重质有机质富含碳氢共价结构,其轻质化和定向化学品转化是加工利用的主要目标。热解是重质有机质加工过程中最直接、最基础的反应过程,挥发物作为重要的热解产物,其组成分布及在热解过程的演变规律解析是研究的关键和热点问题。本文综述了重质有机质热解过程中挥发物的生成过程,总结了反应类型及产物组成随温度升高的阶段性变化,并以煤、油砂、油页岩、生物质、含油污泥、市政污泥以及废橡胶为例,对比了不同种类的重质有机质热解挥发物产出的异同。针对重质有机质挥发物逸出特性分析方法,本文重点介绍了质谱、傅里叶变换红外光谱逸出气体分析技术,举例说明了各方法在重质有机质有机结构解析、热解工艺条件优化、污染物控制、催化剂设计等研究上的应用,并且就现阶段热解过程逸出气体的定量分析方法和应用进行了概述。最后,本文还就重质有机质热解逸出气体分析技术提出了建议和展望,以期为重质有机质的热解研究提供参考和借鉴。     

Effect of moisture on sewage sludge combustion temperature profile and heavy metal leaching

Moisture is the most important parameter affecting sewage sludge treatment efficiency and cost. In this article, the effect of moisture on sewage sludge combustion temperature profile and heavy metal leaching behavior has been experimentally studied. The temperature profiles inside the sludge pellet were recorded, and the volume shrinkage was obtained by image processing method. Results revealed that combustion rate and burnout of sludge strongly depends on moisture content and there exists an optimal moisture content for sludge incineration with respect to best combustion performance and minimum heavy metal leaching. The enlarged pore size may account for this moisture rate, that is, 48% for the sludge studied. During combustion, the shrinkage rate varied from 15 to 25%, and it was found to be proportional with moisture content. The cross-section image of burning sludge pellet illustrated that during the drying and combustion stage, the moisture evaporation was running parallel with the decomposition of volatile that was burned out in the vicinity of the sludge surface. Measured temperature profiles indicate that effect of volatile combustion on inner temperature profile was ignorable. A mathematic model taking sludge volume shrinkage into consideration has been developed to predict sludge central and surface temperature during combustion.     

城市污泥中重金属存在形态、去除及稳定化研究进展

城市污水处理厂污泥产生量大,含有丰富的有机质、氮、磷、钾等农作物所需营养物质,但由于受重金属的污染使污泥无法直接农用。本文简述了城市污泥重金属的来源、特点及危害。重点论述了城市污泥中重金属去除和稳定方法,包括化学法（电化学法、化学试剂法）、生物法（微生物法、植物法、低等动物法）、物理法（超临界流体萃取、微波和超声）及联合技术。分析了各种方法处理污泥重金属过程中重金属的形态变化及其对处理效果的影响,对比各种方法的优缺点、影响因素及适用范围。指出污泥中重金属形态分布是影响去除效果的关键因素,污泥中重金属形态分布差异性大,且大部分重金属以稳定或相对稳定的状态存在,导致物理法和生物法去除效率较低,微生物和低等动物处理法相比植物法（备受时空限制）则表现出更好的适应性;电化学法对可氧化、可还原态分布的重金属都能起到较好的转化去除作用,但往往受由污泥向污泥液相中转移过程的控制,电损耗较突出;化学试剂浸提剂是目前效率较高的方法,但强酸环境常导致污泥营养物质流失和酸根离子累积,农用时容易板结而不利于污泥土地利用。因此,以土地利用为前提的条件下,将各种处理技术联合运用以提高污泥重金属去除率有待于进一步研究。     

Solidification/stabilization of thermally‐treated toxic tannery sludge

The high concentration of trivalent chromium along with organic/inorganic compounds in tannery sludge causes severe ground‐water contamination in the case of land disposal and chronic air pollution during incineration. In the present investigation the sludge was subjected to starved‐air combustion at 800 °C, which prevented the conversion of Cr³⁺ to Cr⁶⁺. The efficiency of starved‐air combustion was confirmed through differential thermo‐gravimetric analysis (DTG), electron spin resonance (ESR) and Fourier transform infrared (FTIR) analysis. The calcined sludge was solidified/stabilized using fly ash, clay, lime and Portland cement as mixture constituents. The solidified specimens were tested for compressive strength and heavy metal fixation. The compressive strength and metal fixation of the calcined sludge (Cs)–fly ash (F)–cement (C) mortar at a ratio of 41.66% Cs, 41.66% F, 16.66% C were 185 kg cm^?2 and 93.84%, respectively. The stabilization of chromium(III) in the cement gel matrix was confirmed with scanning electron microscopy. Leachability studies were carried out to determine the percentage of metal fixation and chemical oxygen demand in the leachate. Copyright © 2006 Society of Chemical Industry     

Fly ash—a potential source of soil amendment and a component of integrated plant nutrient supply system

In sub-tropical climate the high rainfall and high temperature is responsible for low soil productivity due to losses of bases and low organic matter content in soil. In acid lateritic soil low availability of P and high content of Al and Fe posses nutritional imbalance which is generally corrected by lime materials. Alkaline fly ash can be used in such problematic soil as an amended material and also it acts as source of plant nutrition for crop production. An attempt was made to develop an integrated plant nutrient supply system utilizing the fly ash along with other organic wastes like paper factory sludge, farm yard manure, crop residue and chemical fertilizers for rice-peanut cropping system. Direct and residual effects of fly ash were assessed based on crop yield, nutrient uptake and changes in soil characteristics. The application 10 t ha⁻¹ of fly ash in combination with organic sources and chemical fertilizer increased the grain yield and nutrient uptake of rice, and pod yield of peanut compared to chemical fertilizers alone. The heavy metal contents in plant and soil system was analyzed and found to remain below the permissible level. The results indicated that fly ash could be applied safely to tropical agro eco-systems for retaining productivity of acid lateritic soil.     

城市垃圾焚烧飞灰中重金属形态及生物有效性研究

随着集中焚烧法逐渐成为我国城市生活垃圾处理的主要方式,焚烧飞灰的安全处置与利用也成为学者普遍关注的问题。由于在填埋过程中受到各种环境要素的影响,垃圾焚烧飞灰中的重金属有可能会发生迁移和转化,重金属形态、毒性也会随之变化。本文对不同粒径城市垃圾焚烧飞灰中重金属的总量、形态及生物有效性进行了研究,为其在安全填埋及资源化利用过程中预测重金属的环境风险提供参考。