城镇污水处理厂污泥稳定化处理产物转化机理及可利用价值揭示

以污泥厌氧消化、好氧发酵为代表的稳定化处理是污泥处理应用最广泛的工艺,也是与处理产物资源化处置相衔接最主要的方法。以全国十余座采用厌氧消化、好氧发酵的污泥处理厂为研究对象,分析了稳定化处理过程中污泥处理产物的转化机理和处理产物的形态、特征、稳定性及其土地利用价值。在研究污泥稳定化处理过程有机物(蛋白质、多糖等)降解过程的同时,重点探索了复杂、稳定的大分子有机质(富里酸、胡敏酸等)的合成机理,以及对土壤和植物的重要价值。这些稳定的大分子有机质因含有多种活性含氧官能团,是土壤结构的稳定剂、改良剂,重金属的固定剂,微量元素的溶解剂以及植物养料的"仓库",研究成果对污泥稳定化处理产物的资源化利用有重要价值和意义。同时结合产物中稳定的大分子有机物具有荧光特性,提出用产物中腐殖酸含量和产物的荧光复杂指数来判定产物的稳定化程度,规范了污泥稳定化程度的判定方法。     

污泥活性炭的制备及其用于重金属废水处理的研究进展

城市污水处理厂在处理污水的同时会产生大量的污泥,其含有大量有机物和有害物,性质不稳定,易腐化,如果处理不当,将会造成严重的环境污染和资源浪费.用城市污水处理厂污泥制备活性炭是20世纪80年代后期出现的一种新型利用途径,因其制备成本低,活性炭用途广泛,可以用于污水处理去除有毒有害物质,具有良好的环境效益和社会效益,引起国内外研究人员的关注.而有毒重金属对环境的严重威胁正逐渐成为全球性问题,活性炭吸附法是一种常用来处理重金属废水的方法.综述了国内外污泥制备活性炭的工艺方法,及在这些制备方法基础上对重金属废水的处理研究.     

污水处理厂板框污泥好氧堆肥养分及重金属形态变化的研究

以板框压滤机脱水泥饼为研究对象,对板框污泥好氧堆肥进行了研究,对比堆肥前后污泥的理化性质、营养成分、卫生学指标及重金属的变化,并采用BCR提取-电感耦合发射光谱法对堆肥前后污泥中的铬、铜、镍、铅和锌进行了形态分析。结果表明好氧堆肥可降低板框污泥中重金属的生物有效性,可以成为解决污泥土地利用重金属污染的一个有效途径,为污水处理厂板框污泥资源化利用提供了借鉴作用。     

城市污泥基本特性与安全处置

通过分析污泥的基本特性，如含水率，燃烧值，污泥的肥分及污泥中的重金属含量和营养物质的含量，来进一步研究分析污泥的处置方法。着重介绍了卫生填埋、污泥焚烧、水体消纳等处置方法，以及污泥在农业、建材方面的安全应用，为污泥的安全处置及资源化利用提供了依据。     

基于EDTA淋洗离心—硫酸盐还原菌固化法去除污泥中重金属镉的研究

为研究如何分离和去除污泥中重金属镉（Cd）,采取二氨基乙烷四乙酸(ethylene diamine tetraacetic acid, EDTA)淋洗离心与硫酸盐还原菌( sulfate-reducing bacteria, SRB)固化相结合的方法进行了污泥试验并统计分析了污泥中重金属Cd的形态分布和含量变化。结果表明：在离心力100g、淋洗时间12 h、淋洗2次和离心温度30 ℃的条件下采用EDTA对污泥原样进行淋洗离心,污泥中Cd含量由6.793 mg/kg降至5.241 mg/kg,去除率达22.8%。然后采用SRB对淋洗离心后的污泥试样进行固化,不稳定态Cd含量由2.589 mg/kg降至1.103 mg/kg,固化后污泥中的Cd含量低于《绿化种植土壤》（CJ/T 340-2016）中重金属要求的Ⅳ级标准2 mg/kg。与传统单一修复方法相比,该联合方法有效地降低了污泥中活性大、污染程度高形态Cd的含量,减轻了其环境危害性。     

亚临界水处理技术处理污泥效果的初步试验

污泥的无害化和资源化是污泥处理和处置的难点,通过进行四次初步的试验,对亚临界水处理技术处理污泥的效果进行了定性分析。试验结果表明,亚临界水处理技术对去除污泥中重金属有一定效果,对污泥中生物病菌的灭活有显著效果,处理后污泥的营养成分也满足污泥农用标准。     

生物膜法在污水处理中的研究进展

生物膜法在污水处理工艺中是与活性污泥法并行的一种好氧型生物污水处理方法,广泛的应用于工业废水和城市污水处理的二级处理中,也是污水处理的关键环节。与活性污泥法相比,生物膜法具有一些特有优势。比如无需污泥回流,运行管理容易,无污泥膨胀问题,易于微生物生存,运行稳定等。文中简单介绍了生物膜法对磷、氮及一些重金属去除的研究进展。     

城市污泥处理与利用标准化技术体系研究

城市污泥具有污染与资源利用的双重属性,如何规范的限制污染性、发挥资源性,对于城市污泥的处置与利用就显得至关重要。构建城市污泥标准化技术体系能为城市污泥的处理利用提供科学依据,有效促进城市污泥的合理处置与资源化利用。通过分析我国城市污泥技术标准制定与管理现状,借鉴国外发达国家城市污泥标准制定与管理的经验和成果,基于城市污泥处理与利用的技术环节和流程,提出了我国城市污泥标准体系建设框架。     

城市污泥资源化利用现状及发展探讨

随着城市污泥产量连年增长,污泥处理问题迫在眉睫。由于用地日益紧张和潜在的环境污染问题,传统的处置方法如填埋已经不符合发展要求。作为污水处理厂的伴生产物,污泥含有大量有机物、氮、磷等营养物质,经过适当处理,可以变废为宝。因此,资源化利用是解决污泥问题的主要发展趋势。通过分析国内外城市污泥的处置现状,对污泥资源化技术进行了分类,并就污泥在土地利用、建材利用、能源利用和其他方面的应用进行了详细综述,同时还分析了资源化利用存在的问题,指出污泥资源化利用和发展需要因地制宜、合理开发,需要继续提高工艺水平,推进技术创新,完善政策法规。     

消化污泥农用中重金属影响的研究

对城市污水处理厂消化污泥中的重金属形态分布及农业利用后对土壤、果实的影响进行了分析、试验。结果表明 ,消化污泥中 8种重金属的化学形态以稳定态为主 ,植物可吸收量极少     

Heavy metals speciation in soakaways sediment and evaluation of metal retention properties of surrounding soil.

Heavy metals speciation analysis was carried out on sediment samples accumulated within soakaways in an old stormwater infiltration facility in Tokyo, Japan and on a soil core sample collected near the facility. Heavy metals content in soakaways sediments were much elevated compared to nearby surface soil with the content for Zn, Pb and Cd reaching about 5 to 10 times the content in surface soil. Speciation results revealed that significant amount of the accumulated heavy metals were present in potential mobile fractions, posing threat of release to underlying soil with changing environmental conditions. Detail analyses of soil characteristics indicated significant heterogeneity with depth, especially between the surface soil and underlying soil at site. Decrease in potential adsorption sites with depth was observed in case of underlying soil. Reduced adsorption capacity for heavy metals was evidenced for underlying soil when compared with surface soil. Furthermore, less capability of the soil organic matter to bind heavy metals was evidenced through speciation analyses, which raises concern over the long-term pollution retention potential of the underlying soil receiving infiltrated runoff.     

Processing dewatered sewage sludge using electrokinetic technology.

High content of heavy metals and presence of pathogens in the dewatered sewage sludge have been the main obstacles for land application of sewage sludge-made fertilizer. The aim of this study was to examine the effects of the innovative electrokinetic (EK) technology on removal of heavy metals from sewage sludge, on the reduction of pathogens, and on sludge chemical characteristics. The results showed that the removal efficiencies for Zn, Cu, Ni, Cr, As and Pb were 94.9%, 95.4%, 89.7%, 67.8%, 31.2% and 18.7%, respectively. Acidification pretreatment of the dewatered sludge for 29 h decreased the content of heterotrophic bacteria from 1.5 x 10(8) c.f.u./g of wet sludge to 1.1 x 10(4) c.f.u./g of wet sludge. Although the initial content of total coliforms and fecal coliforms in sewage sludge were 5.8 x 10(5) c.f.u./g of wet sludge and 4.0 x 10(5) c.f.u./g of wet sludge, respectively, no viable cells were detected. Minor losses of K and N were detected, but the loss of P was found to be significant in EK treated sewage sludge. The treated sludge was technically considered as very stable based on the carbon dioxide evolution rate.     

Recycling of sludge with the Aqua Reci process.

Supercritical Water Oxidation (SCWO) is an innovative and effective destruction method for organics in sewage sludge. The SCWO process leaves a slurry of inorganic ash in a pure water phase free from organic contaminants, which opens possibilities for a simple process to recover components like phosphates and/or coagulants from the sewage sludge, a process marketed as the Aqua Reci. In a continuous pilot plant for the SCWO process digested sludge has been treated. The ash has been extracted in lab- and pilot scale with both caustic and acids in order to recover phosphates and coagulants. The particle size of the inorganic contaminants in the water after the SCWO process is between 1-10 microm, which means that it is very reactive. The phosphate, and partly the aluminium, can be extracted with caustic as iron and heavy metals are completely insoluble in caustic. This is a method to separate the phosphates from the rest of the contaminants. However, high calcium content will bind the phosphate as calcium phosphate insoluble in caustic. In most cases the calcium content is too high and the best solution is to dissolve phosphates and all metals with sulphuric acid. From this solution first iron phosphate can be separated and thereafter in a second step aluminium and finally heavy metals in a third step. Iron can be separated from the phosphate, either by leaching the phosphate with caustic off to sodium phosphate leaving a precipitate consisting of iron hydroxide, or the iron phosphate can be dissolved in hydrochloric acid followed by a liquid extraction process where ferric chloride can be separated leaving a phosphoric acid. By the acid dissolving process it is possible to recover phosphate, iron, aluminium, and heavy metals from the inorganic since the Aqua Reci process only leaves a silica residue representing about 10% of the DS content in the original sludge.     

生物活性剂淋洗对河道底泥重金属毒性和生态风险影响评价

以河道底泥为研究对象,采用Tessier五步连续提取法比较了淋洗前后底泥中重金属的形态分布变化,并采用生物活性评价法,浸出毒性法,地累积指数法和潜在生态风险指数法比较及评价了生物活性剂槐糖脂淋洗前后底泥重金属的生物活性、浸出毒性和生态风险系数的变化。研究同时还采用三维荧光对底泥中溶解性有机质进行了分析。结果表明:淋洗后底泥重金属形态分布发生变化,重金属的迁移能力降低,生物活性和危害性降低,浸出毒性减小,单一和综合潜在生态风险降低,说明淋洗是一种有效的降低底泥重金属环境危害的方法。经淋洗后的底泥中重金属稳定性提高,对生态风险小,可以进一步进行资源化利用。     

Pollutant monitoring in sludge treatment wetlands

Phragmites australis for sludge dewatering and stabilization processes have been widely proved. The presence of reeds, indeed, efficiently allows solids dewatering and organic matter stabilization in order to obtain a stabilised product that can be suitable for land application, even if its environmental impact has to be considered. The actual revision of the European Union's Working Document on Sludge (2000), in fact, seems to be addressed to detect two principal categories of pollutants in sludge for agricultural use: heavy metals and toxic organic compounds. In this study are presented results about sludge stabilization and monitoring of heavy metal fractionation and organic compounds in four urban wastewater treatment plants managed by Acque S.p.A., (Tuscany, Italy). To evaluate the process of sludge stabilization parameters were determined that highlight the biochemical and chemico-structural properties of sludge organic matter. The results showed that stabilization of the sludge over time occurred as shown by the low content of water soluble carbon and dehydrogenase activity, and by the re-synthesis of humic-like matter highlighted by the pyrolytic indices of mineralization and humification. Results about fractionation showed that heavy metals were retained in fractions related to the stabilized organic matter. Moreover, toxic organic compounds showed a drastic reduction at the end of the monitoring period.     

Application of ionic liquids for the removal of heavy metals from wastewater and activated sludge

This paper presents the results of adsorption studies on the removal of heavy metals (Cr, Cu, Cd, Ni, Pb and Zn) from standard solutions, real wastewater samples and activated sewage sludge using a new technique of liquid-liquid extraction using quaternary ammonium and phosphonium ionic liquids (ILs). Batch sorption experiments were conducted using the ILs [PR4][TS], [PR4][MTBA], [A336][TS] and [A336][MTBA]. Removal of these heavy metals from standard solutions were not effective, however removal of heavy metals from the industrial effluents/wastewater treatment plants were satisfactory, indicating that the removal depends mainly on the composition of the wastewater and cannot be predicted with standard solutions. Removal of heavy metals from activated sludge proved to be more successful than conventional methods such as incineration, acid extraction, thermal treatment, etc. For the heavy metals Cu, Ni and Zn, ≥90% removal was achieved.     

Sustainable sludge management in developing countries.

Worldwide, unsanitary conditions are responsible for more than three million deaths annually. One of the reasons is the low level of sanitation in developing countries. Particularly, sludge from these regions has a high parasite concentration and low heavy metal content even though the available information is limited. Different issues needed to achieve a sustainable sludge management in developing nations are analysed. Based on this analysis some conclusions arise: sludge management plays an important role in sanitation programs by helping reduce health problems and associated risks; investments in sanitation should consider sludge management within the overall projects; the main restriction for reusing sludge is the high microbial concentration, which requires a science-based decision on the treatment process, while heavy metals are generally low; adequate sludge management needs the commitment of those sectors involved in the development and enforcement of the regulations as well as those that are directly related to its generation, treatment, reuse or disposal; current regulations have followed different approaches, based mainly on local conditions, but they favour sludge reuse to fight problems like soil degradation, reduced crop production, and the increased use of inorganic fertilizers. This paper summarises an overview of these issues.     

Dynamic of lead speciation in sewage sludge composting.

A large-scale sewage sludge composting experiment was conducted to develop an understanding of changes that occur to Pb chemical speciation, distribution and bio-availability during the course of composting. The four-stage Tessier sequential extraction method was employed to investigate the dynamics of heavy metal Pb speciation (exchangeable, bound to carbonates, bound to Fe-Mn oxides, bound to organic matter and sulphides, residual) during the course of sewage sludge composting. The concentrations of the total Pb and the five Pb fractions concentrations were increased during the whole stage of compost. However, the percentages of Pb distribution with respect to total Pb were changed in the following manner: exchangeable, bound to Fe-Mn oxides and bound to carbonates Pb with respect to total Pb were increased, while the percentages of bound to organic matter and sulphides, and residual Pb with respect to total Pb were decreased during composting. The data showed that the quantity of Pb in the less toxic portion, such as consisting of organic matter and sulphides bound and residual Pb, was increased, and that the contamination and bio-availability of heavy metal Pb in sewage sludge was reduced during the composting process.     

太湖疏浚底泥的脱水技术研究

太湖环保疏浚工程产生大量高含水率的疏浚底泥,处置不当就造成十分严重的二次污染。由于疏浚底泥重金属含量基本低于农用污染物控制标准,合理施用即可改良土壤、节约大量处置费用,不仅能够解决我国土壤退化的问题,还能带来良好的经济效益。为实现底泥的快速脱水,便于资源化利用,同时针对疏浚底泥渗水性差致使底部排水法困难的缺点,采用了絮凝剂、脱水剂与真空抽滤相结合的方法处理疏浚底泥。试验结果表明:加药实验组在520h内可将疏浚底泥的含水率从70%降至41.9%,而不加入药剂的空白组实验含水率只降至60.3%就无法继续脱水。所用脱水剂不与絮凝剂、淤泥和淤泥中的有机质等成分发生化学反应,且对出水水质无明显影响,出水的浊度、CODMn以及pH值在废水排放的规范之内。