城市污泥资源化利用研究

城市污水污泥产量巨大且成分复杂 ,如何对它进行合理利用已越来越受人们关注。文章系统地综述了我国城市污泥处置与利用的现状和趋势 ,并重点讨论了污泥土地利用的可行性以及我国近年来的研究进展。认为将污泥进行稳定化、无害化、资源化处理并作为有机肥料或土壤改良剂等进行资源化利用是符合我国国情的 ,并将成为我国污泥处置与利用的一种有效途径     

城市污泥农用对植物-土壤系统的影响

城市污泥的合理处置是目前资源与环境科学研究领域中的重要课题之一.城市污泥因富含大量的有机质和有效营养成分,对农业土壤肥力、土壤物理结构和农业生产均有一定的积极促进作用,使得污泥农用成为可能.但城市污泥中含有的重金属、有机污染物等有害物质尤其是重金属,成为污泥农用处置的瓶颈.为提高我国城市污泥的农业资源化利用效率和减少污染物造成的负面效应,本文就国内外施用城市污泥对植物-土壤互作系统的影响及过程进行了综述,为进一步提高污泥利用效率提供理论依据和科学指导.     

论城市污泥农用资源化与可持续发展

根据可持续发展观的基本思想，在对城市污泥的特征、处理现状及其对农业和城市发展的影响进行分析的基础上，认为城市污泥的农用资源化对于城市和农业的可持续发展具有重要意义和紧迫性，也是未来城市污泥处置的根本出路，关键在于控制污泥中毒性污染物的含量，科学合理地施用。     

蚯蚓作用下污泥重金属形态变化及其与化学生物学性质变化的关系

城市污泥处理是一项世界性难题,污泥农业利用是其最简单有效的资源化利用方式之一,但污泥中较高的重金属含量限制了其实际推广应用,利用蚯蚓-超富集植物联合修复污泥重金属的方法已引起国内外研究者的关注。以新鲜城市脱水污泥为研究对象,接种赤子爱胜蚓(Eisenia fetida)进行室内培养试验,系统研究蚯蚓作用下污泥重金属形态的变化,及其与污泥氧化还原条件、化学和微生物性质变化的关系,以期为蚯蚓-超富集植物联合修复技术在污泥重金属处理中的应用提供理论依据。结果表明,试验前期蚯蚓在污泥中能正常生长和存活,前20 d总生物量增加了52%。蚯蚓可以显著促进污泥中的Cu、Zn、Cd、Ni等重金属从残渣态和铁锰态等稳定形态向交换态和水溶态等有效形态转化。还可以显著降低污泥中还原性物质的含量,减缓p H值下降速度,降低总有机碳含量,促进铵态氮向硝态氮转化,减少污泥微生物的数量并增加其种群活性。蚯蚓作用下,污泥中重金属的活化程度与还原性物质的含量呈显著负相关,而与微生物种群的活性呈显著正相关(P0.05)。综上所述,蚯蚓可以促进污泥重金属的活化,并改善污泥的肥力条件,为修复植物在污泥中的正常生长和对重金属离子的快速吸收提供有利条件。     

剩余污泥资源化利用新工艺研究进展

随着城市化进程加速, 污水处理厂剩余污泥大量产生, 如何对其进行处理并有效资源化利用成为广泛关注的问题。文章在综述我国城市污水处理厂剩余污泥特征、相应处理与综合利用方法的基础上, 进一步综述了污泥干化芦苇床、人工湿地、微生物燃料电池以及相关组合工艺等剩余污泥资源化利用新工艺。总结了各种新工艺的优势以及当前尚未解决的关键问题, 对未来新工艺的潜在应用进行了展望, 以期开发出低能耗、低成本、高效率、绿色生态的技术, 真正实现剩余污泥的减量化、无害化、稳定化和资源化。     

碱-组合工艺预处理剩余污泥研究进展

城市污泥在进行厌氧发酵处理时,所需时间长、SS降解率低、产气量也低,难以有效达到污泥减量化的目的(VS去除率30％左右).污泥的厌氧发酵包括水解、酸化、产乙酸、产甲烷的过程.研究发现在污泥进行厌氧发酵过程中固态有机物的水解、酸化是限速步骤,因此为了促进污泥的水解、酸化,使更多的固体有机物转化为水溶性的有机物,进而提高厌氧发酵的效率实现污泥的减量化、无害化和资源化利用,对污泥预处理是必须的.该文着重介绍了NaOH及其组合工艺对污泥预处理的影响.     

城市污泥应用于陆地生态系统研究进展

随着城市化进程加快和人口剧增,城市污泥已成为世界许多城市面临的主要环境问题之一,且不合理的管理可引发严重的环境污染.城市污泥含有大量、微量元素和有机质,可能对土壤及其生产力有利,特别对退化土壤能进行有机修复,并改善土壤理化特性,譬如土壤结构和营养含量.目前,污泥作为一种有机肥料已成为普遍措施.但来自工业及生活污水的污泥常含有重金属、病原物及有毒有机物等,潜在的毒性可能对生态系统构成危险,因此必须经过污泥预处理才可安全施用.评述了近年来国内外污泥应用于陆地生态系统4个方面的主要研究进展:(1)污泥处理与处置方法;(2)污泥应用于农田、草地及森林生态系统;(3)污泥对土壤生态系统的影响,包括污泥对土壤理化性质、土壤酶及微生物的影响;(4)污泥应用的环境效应.提出未来我国污泥处置及利用需要重视的研究领域和方向.     

利用混合厌氧堆肥进行污水处理的研究

目的：采用堆肥技术处理城市污泥以实现城市污泥的农用资源化进行了研究。方法：重点分析了污泥与粉煤灰混合厌氧堆肥过程中重金属铜稳定化的效果,分别按照污泥与粉煤灰质量比为1∶1;3∶1和4∶1进行混合,在常温下进行厌氧堆肥17d。结果：实验表明污泥与粉煤灰3∶1混合堆肥过程中铜的稳定化效果最佳。结论：堆肥过程有利于污泥的资源化利用。     

中国城市污泥土地利用关注的典型有机污染物

污泥土地利用是国内外城市污泥主要的处置方式之一,而污泥中的有机污染物是污泥土地利用的限制性因素之一.本文分析了国内外城市污泥中有机污染物的浓度和研究现状,针对我国国情,认为多环芳烃(PAHs)是城市污泥中一种常见的有机污染物,总含量一般在1 ～ 10 mg·kg-1,有的因污水来源复杂而超过了100 mg·kg-1;壬基苯酚(NP/NPE)在我国污水处理厂污泥样品中均有检出,浓度在1～128 mg·kg-1.污泥园林绿化、林地利用、土壤改良等将是今后主要的利用方向,要实现污泥安全、环保的土地利用,多环芳烃(PAHs)和壬基苯酚(NP/NPE)将是主要考虑的典型有机污染物.     

城市污泥堆肥对栽培基质保水能力和有效养分的影响

盆栽试验表明 ,城市污泥堆肥不仅可以明显提高栽培基质的有效氮、磷含量 ,而且可以增强栽培基质的保水性能和植物的抗旱能力 ,但是栽培基质的萎焉点也随着其用量的增加而增高。因此 ,从保证植物水分供应的角度考虑 ,虽然可以大量地使用城市污泥堆肥 ,但是其用量并不是越多越好 ;当用量超过 75 %时 ,继续增加城市污泥堆肥的比例 ,则植物的吸水能力反而会略有下降。从养分供应和保水性能等角度综合考虑 ,采用经过堆肥化处理的城市污泥作为植物栽培基质 ,是城市污泥资源化和无害化的可行途径     

Phytotreatment of Sewage Sludge Contaminated by Heavy Metals and Pahs by Co-Planting Sedum Alfredii and Alocasia Marorrhiza

High concentrations of heavy metals and organic pollutants in municipal sewage sludge are key factors limiting its use in agriculture. The objectives of this study were to decrease the heavy metal and polycyclic aromatic hydrocarbon concentrations in sewage sludge by phytotreatment and to determine, in a field experiment, whether co-planting is more effective than using a mono-crop of Sedum alfredii. Four treatments were used in the plot experiment: no sludge, no plants, S. alfredii and co-planting S. alfredii and Alocasia marorrhiza. The results showed that co-planting produced tubers and shoots of A. marorrhiza that were suitable as a safe animal feed and good organic K fertilizer, respectively. Co-planting was more effective than mono-planting at reducing concentrations of total Zn and diethylenetriaminepentaacetic acid (DTPA)-extractable Zn, Cd, and Cu in the sludge. Co-planting decreased the concentrations of DTPA-extractable heavy metals and benzo[a]pyrene (B[a]P) in the sludge significantly compared with the unplanted sludge. Decreases of 87, 75, 85, 31, and 64% were obtained for B[a]P and DTPA-extractable Zn, Cd, Cu, and Pb, respectively, compared with the fresh sludge. These results indicate that co-planting can reduce significantly the environmental risks associated with heavy metals and B[a]P in sewage sludge for further disposal.     

城市污泥堆肥用作草皮基质对草坪草生长的影响

研究了城市污泥堆肥生产草坪基质的应用效果。试验结果表明,城市污泥堆肥基质能明显提高黑麦草的地上和地下生物量和叶绿素含量,与不施化肥和施用化学的对照相比,城市污泥堆肥可以增加土壤有效态氮、磷含量,促进植物叶片对氮的吸收,提高草坪的质量。用经过无害化处理的城市污泥生产草坪基质,既可以解决城市污泥的出路,又可以降低草坪的生产成本,是一条经济可行的途径。     

城市垃圾堆肥及其复合肥对黑麦草草坪质量的影响

为加速城市生活垃圾堆肥农业资源化利用研究,避免重金属等有害物质进入食物链,利用盆栽试验,研究了垃圾堆肥及以其为原料研制而成的3种复合肥的不同施肥水平对土壤肥力,黑麦草生长及草坪质量的影响,以选取最佳的适合黑麦草生长的垃圾肥料及其施用量。共设空白、堆肥、化肥、复合肥1、复合肥2、复合肥3等6个处理,每个处理又分为高、中、低3种施肥水平,测试草坪生物指标的质量状况和土壤肥力。结果表明:与化肥比较,垃圾复合肥可以显著提高土壤有机质、全氮、碱解氮、全磷的含量。垃圾复合肥明显促进了黑麦草的茎与根系的生长,提高了生物量,改善了叶片的色泽和整齐度,提高了草坪的密度和质量;促进了黑麦草对氮的吸收,尤其是生长后期,叶片中氮和叶绿素的含量明显高于化肥与空白处理,且差异显著。草坪质量综合评价以垃圾复合肥1的中量施肥处理为最好,黑麦草分蘖最高,地上生物量适度;除复合肥的高量施肥处理外,复合肥1的中量施肥处理茎叶中氮素和叶绿素含量最高,草坪品质最高。     

Near-Bottom Pelagic Bacteria at a Deep-Water Sewage Sludge Disposal Site

The epibenthic bacterial community at deep-ocean sewage sludge disposal site DWD-106, located approximately 106 miles (ca. 196 km) off the coast of New Jersey, was assessed for changes associated with the introduction of large amounts of sewage sludge. Mixed cultures and bacterial isolates obtained from water overlying sediment core samples collected at the deep-water (2,500 m) municipal sewage disposal site were tested for the ability to grow under in situ conditions of temperature and pressure. The responses of cultures collected at a DWD-106 station heavily impacted by sewage sludge were compared with those of samples collected from a station at the same depth which was not contaminated by sewage sludge. Significant differences were observed in the ability of mixed bacterial cultures and isolates from the two sites to grow under deep-sea pressure and temperature conditions. The levels of sludge contamination were established by enumerating Clostridium perfringens, a sewage indicator bacterium, in sediment samples from the two sites. The results of hybridization experiments in which DNAs extracted directly from the water overlying sediment core samples were used indicate that the reference site epibenthic community, the disposal site epibenthic community, and the community in a surface sludge plume share many members. Decreased culturability of reference site mixed cultures in the presence of sewage sludge was observed. Thus, the culturable portions of both the autochthonous and allochthonous bacterial communities at the disposal site may be inhibited in situ, the former by sewage sludge and the latter by high pressure and low temperature.     

Minimization of excess sludge production by in-situ activated sludge treatment processes — A comprehensive review

The widespread application of conventional activated sludge treatment process has been employed to deal with a variety of municipal and industrial sewage. While the generation of waste activated sludge (WAS) was considerably huge, the management and disposal expenses were substantially costly. A promising process aimed for WAS reduction during the operation process is urgently needed. Thus, increasing attentions emphasizing on the improved or novel sludge reduction processes should be intensively recommended in the future. This review presents the current and emerging technologies for excess sludge minimization within the process of sewage treatment. The ultimate purpose of this paper is to guide or inspire researchers who are seeking feasible and promising technologies (or processes) to tackle the severe WAS problem.     

Cooperation between two Thiobacillus strains for heavy-metal removal from municipal sludge.

A mixed culture of two fast-growing bacterial strains for heavy-metal solubilization of municipal sewage sludge has been developed. Strain VA-7 decreases the initial sludge pH (7-8.5) to a value between 4.0 and 4.5. Then, strain VA-4 begins growing and further reduces the pH to values below 2.0. The rapid decrease of sludge pH by a mixed culture through sulfur oxidation into sulfuric acid solubilizes the toxic metals (Cd 83-96%, Cr 16-54%, Cu 85-87%, Mn 91-94%, Ni 78-79%, Pb 28-46%, Zn 82-96%) to levels recommended for intensive use of residual sludge in agriculture. A study of the physiological and metabolic characteristics of these strains revealed that isolate VA-7 is a strain of Thiobacillus thioparus (ATCC 55127), while isolate VA-4 corresponds to a Thiobacillus thiooxidans (ATCC 55128). These bacterial strains possess distinctive physiological characteristics that allow them to easily grow and solubilize heavy metals in municipal sludge.