城市污泥堆肥过程中不同类型有机物的动态变化

研究了城市污泥高温好氧堆肥过程中各类有机物的动态变化.结果表明,污泥经30 d堆肥后,总有机质、DOC和易分解有机质的含量分别由469 g/kg、8 234 ms/kg、98.3 g/kg下降至225 g/kg、4 977 mg/kg、70 g/kg;腐殖质和胡敏酸含量升高,富里酸含量显著降低;污泥堆肥过程中有机物不断向腐殖化方向转化,污泥中有机质逐渐趋于稳定.污泥堆肥处理有助于提高其土地利用的肥料价值和降低环境风险.     

城市低有机质污泥的好氧堆肥研究

针对低有机质含量污泥和难降解调理剂混合堆肥时因发热量不足而易导致堆肥失败的问题,利用草坪碎屑作为污泥堆肥的调理剂,考察了添加草屑发酵物后低有机质污泥的好氧堆肥效果.结果表明,草屑发酵后可转化为易被微生物利用的外加碳源,有利于低有机质污泥的堆肥;将发酵青草按1：5的质量比加到低有机质污泥中,混合后在强制通风条件下进行好氧堆肥,能使污泥堆肥温度升至55℃,并维持3 d以上,使污泥达到无害化和稳定化;对腐熟后的污泥进行植物栽培试验,证明了其可作为有机肥使用,并具有良好的效果.     

城镇污水处理厂污泥堆肥减量工业废弃物的研究

以某城镇污水处理厂脱水污泥、某面粉厂废弃麦壳、某制药厂废弃黄姜渣为堆肥原料,按1∶3∶1的体积比进行混合堆肥试验,探讨堆肥过程中污泥物化指标、生物指标及养分的历时变化。结果表明:以城镇污水厂污泥为主要原料,以麦壳和黄姜渣为添加剂,堆肥过程高温阶段维持了12 d,含水率按指数关系递减,蠕虫卵死亡率和粪大肠菌群值达到污泥农用的卫生学指标;30 d时堆肥的p H值、有机质及氮、磷、钾满足污泥农用的营养学要求,总养分含量和有机质含量分别为56.15和338.54 g/kg;堆肥中主要重金属为Cu、Zn、Pb、Cr,但其含量远小于《城镇污水处理厂污泥处置农用泥质》(CJ/T 309—2009)的限值。因此,该堆肥产品可以作为农业用有机肥料,并实现了污泥与工业废弃物的同步减量和资源化。     

污泥堆肥过程中微生物群落的形态变化研究

将高效除臭发酵菌接种到污泥堆肥中,通过分子生物学技术的引入,对污泥堆肥化过程进行研究,获得反应过程中微生物群落结构随时间变化图谱,直观剖析堆肥过程中细菌群落组成结构的变化,更好地反映堆肥化过程中生物化学的变化。结果表明,在污泥堆肥开始阶段中接入高密度、高活性的菌剂,不仅加快堆肥中有机物的分解、缩短堆肥化过程,而且提高了污泥堆肥的质量。     

污泥堆肥产物在农业利用中的潜力和问题

污泥堆肥处理被认为是适合中国国情的污泥处理处置方式,但其产物的出路是污泥堆肥产业化过程的关键问题。通过总结和分析国内外大量的研究,发现污泥堆肥产物含有丰富的有机质和氮、磷等营养元素,具有潜在的肥力;农业利用对污泥堆肥产物具有潜在需求;污泥堆肥处理后,重金属活性降低,有机污染物得到不同程度的降解,达到农用目的。因此,污泥堆肥产物在农业利用中具有广阔的应用前景和市场。     

城市污泥堆肥处理及其产业化发展中的几个关键问题

污泥堆肥处理后其有机质和N、P等营养元素可被农作物利用,促进作物增产,被认为是适合中国国情的污泥处理与处置方式.但受处理技术水平、人们的认知和可接受程度的限制以及国家政策法规、产品出路等问题的困扰,城市污泥堆肥处理及其产业化过程仍面临诸多不利因素.为从根本上解决城市污泥的处理与处置难题,城市污泥堆肥处理及其产业化过程中存在的问题必须予以解决,以加快其产业化进程.     

城市污泥堆肥添加猪粪的功效研究

了解和调控高温堆肥过程中堆体内氧气浓度的变化,对于进一步优化堆肥工艺具有重要的意义.为此,利用自主研发的堆肥实时、在线自动监测系统,考察了城市污泥、猪粪以及城市污泥和猪粪混合堆肥过程中氧气浓度的变化.结果表明,添加猪粪可有效改善城市污泥堆肥的通气性;夏季堆肥的通气性好于冬季;降低堆体高度可以适当减少CTB调理剂的用量,并改善了堆体的通气性.     

采用不同调理剂的污泥堆肥稳定度研究

采用 5种调理剂 (木片、麦壳、玉米芯、稻壳和回流堆肥 )进行了中试规模的污泥堆肥 ,对含水率、有机质、总氮、氨氮、硝态氮、BOD5和比耗氧速率 (SOUR)等参数的变化进行了监测。研究结果表明 ,BOD5和SOUR指标适于评价采用不同调理剂的堆肥污泥稳定度。当BOD5<5 0mgO2 gVS和SOUR <0 .5mgO2 (gVS·h)时 ,可认为堆肥污泥达到了稳定和腐熟。     

城市污水污泥与垃圾和粉煤灰堆肥在水稻施肥上的应用

对污泥、垃圾和粉煤灰进行成分及重金属含量检测,用污泥、垃圾和粉煤灰混合堆肥制成有机复合肥,并对水稻进行施肥试验,结果表明：桂林市城市污水污泥及垃圾中有机质和N、P、K含量丰富且不超标,堆肥制成的有机复合肥增产效果显著,具有广泛的应用价值。     

污泥堆肥过程中氮素损失和氨气释放的动态与调控

通过不同鼓风强度、分层堆肥和添加吸湿剂的自动控制堆肥中试,研究了城市污泥堆肥过程中温度、挥发性固体含量、氮素含量和氨气释放浓度的变化.结果表明,在堆肥升温较快的处理中,挥发性固体的降解速度较快,污泥中的氮素容易向氨氮转化,使释放的氨气浓度升高;增大鼓风强度,有利于促进堆肥的升温和腐熟,加速无害化过程,但释放的氨气浓度较高;在保持整个堆体中污泥比例不变的前提下,分层堆肥可以显著提高堆肥的升温效果并减少氨气的释放.     

Behaviour of pathogenic and indicator bacteria during urban wastewater treatment and sludge composting, as revealed by quantitative PCR

Two enteric pathogens, Salmonella spp. and Campylobacter jejuni, and two bacteria commonly used as indicators, Escherichia coli and Clostridium perfringens, were monitored using quantitative real-time PCR during municipal wastewater treatment and sludge composting. The results were compared with those obtained using standard culture methods. A reduction of all bacteria was observed during wastewater treatment and during the thermophilic phase of composting. However, the bacterial groups studied behaved differently during the process, and the main differences were observed during biological treatment in activated sludge basins. In particular, Salmonella spp. and C. jejuni survived better during activated sludge treatment than E. coli. C. jejuni was the most resistant to wastewater treatment among the four bacterial groups. Overall, differences in survival were observed for all bacteria studied, when submitted to the same environmental pressure. This holds both for differences between indicators and pathogenic bacteria and between pathogenic bacteria. These results show the difficulty in defining reliable indicators.     

Biological oxidation and disinfection of sludge

Aerobic digestion, which is biological oxidation of sludge, produces heat. Enough heat is liberated to raise the temperature of the wet sludge up to the pasteurizing range (60–70°C). The major heat loss from an aerobic digester is the latent heat of vaporization of the water vapor which is carried of in the waste air. The use of concentrated oxygen to replace air minimizes this heat loss and theoretically permits thermophilic operation if the initial sludge solids are greater than about 4 per cent. Pilot scale studies have shown that thermophilic aerobic digestion is practical and can be carried out in less than 24 h. Capital and operating costs are reduced and the sludge is pasteurized without the use of external heat. The process is a form of high-rate wet composting and produces a sludge ideally suited for disposal on agricultural lands.Recent and current research data from U.S. EPA-sponsored studies on aerobic digestion of primary sludge solids at Hollywood, Florida; mixed primary and waste activated sludge solids at Hamilton, Ohio; and waste activated sludge solids at Denver, Colorado, are presented and critiqued in light of present design methodology and constraints. These data were obtained under a variety of operating conditions. Data and discussion are also given on the use of pure oxygen in digestion of thickened waste activated sludges.     

Morphological characterisation of ATAD thermophilic sludge; sludge ecology and settleability

Autothermal thermophilic aerobic digestion (ATAD) is a biological wastewater treatment process used for stabilisation of domestic, animal, food and pharmaceutical sludges, and wastewater. It produces a high-quality effluent due to thermophilic processing conditions, however the stabilised sludge has poor settling characteristics, a high water content, low compaction capacity and is difficult to dewater by mechanical processes alone. These factors impact transport and disposal of processed ATAD sludge. We have carried out a detailed morphological characterisation of ATAD sludge at all stages of the ATAD process in an attempt to determine key characteristics of the sludge that might be responsible for its poor dewatering and settleability. A number of microscopic techniques including electron, optical, wide field and laser scanning confocal microscopy were applied to fresh, fixed or embedded sludge taken at various stages during a full scale ATAD process treating domestic sludge. The spatial distributions of structural sludge matrix components were determined and suggested a highly dynamic sludge morphology during the overall process. Large amounts of fibres were observed in the feed sludge, whereas thermophilic sludge liquor with low settleability was shown to have a lower protein to polysaccharide ratio (1:0.9) compared to the easily settled fraction where ratio values were in the range of (1:1.14-1:1.7) with a prevalence of protein constituents. ATAD sludge was also shown to contain colloids, slime, cellulose micro-particles and multiple hydrophobic droplets in the bulk liquor, factors that may markedly impact on sludge dewaterability characteristics. Laser scanning confocal microscopy demonstrated a superior ability to identify composition and spatial localisation of structural constituents in such a dispersed, high water content sludge.     

Factors related to the attraction of flies at a biosolids composting facility (Bariloche, Argentina)

The composting process is used to treat biosolids from the Wastewater Treatment Plant of Bariloche (NW Patagonia, Argentina). Since 1998, an odourless, innocuous and stable organic amendment has been produced at the Biosolids Composting Plant of Bariloche. However, volatile compounds produced during this process, attract different vectors, mainly insects belonging to the Order Diptera, particularly in summer. To evaluate factors associated with the attraction of Diptera to composting windrows, volatile compounds, wind velocity, ambient and windrow temperatures were measured and their relationships with the taxa of flies found were determined. Sampling was conducted several months on newly formed windrows during 3 weeks of the thermophilic composting period. Composite samples from each windrow were taken on the first day of each sampling week, from November 1999 to March 2000 to analyze volatile compounds using an 'electronic nose'. Windrow and ambient temperatures and wind velocity were recorded on three consecutive days of each week, from January to March 2000; also the capture of flies was performed in this period. A weekly mean value was calculated for each environmental variable. Canonical Correspondence Analysis was employed to determine relationships between taxa of flies and the studied factors. The electronic nose discriminated among odours emitted, differentiating windrows by the bulking agent employed and by week of the thermophilic composting period. Ambient temperatures increased slightly during the sampling weeks; the highest values of wind velocity were registered during the second sampling week while windrow temperatures were sustained approximately 60 degrees C. Canonical Correspondence Analysis showed that attraction of flies to composting windrows was related to minimum and maximum ambient temperatures and volatile compounds for Muscina stabulans, Fannia sp. and Acaliptratae and to wind velocity for Ophyra sp., Sarcophaga sp., Cochliomyia macellaria and Phaenicia sericata.     

郑州市污泥堆肥处理工程的设计

郑州市污泥堆肥处理工程处理规模为600 t/d,采用好氧堆肥工艺处置三个污水处理厂的剩余污泥.介绍了工艺流程及发酵槽、混料仓、除臭系统等各处理单元的设计参数,可为相关工程提供参考.     

Mesophilic and thermophilic anaerobic digestion of primary and secondary sludge. Effect of pre-treatment at elevated temperature

Anaerobic digestion is an appropriate technique for the treatment of sludge before final disposal and it is employed worldwide as the oldest and most important process for sludge stabilization. In general, mesophilic anaerobic digestion of sewage sludge is more widely used compared to thermophilic digestion. Furthermore, thermal pre-treatment is suitable for the improvement of stabilization, enhancement of dewatering of the sludge, reduction of the numbers of pathogens and could be realized at relatively low cost especially at low temperatures. The present study investigates (a) the differences between mesophilic and thermophilic anaerobic digestion of sludge and (b) the effect of the pre-treatment at 70 degrees C on mesophilic and thermophilic anaerobic digestion of primary and secondary sludge. The pre-treatment step showed very positive effect on the methane potential and production rate upon subsequent thermophilic digestion of primary sludge. The methane production rate was mostly influenced by the pre-treatment of secondary sludge followed by mesophilic and thermophilic digestion whereas the methane potential only was positively influenced when mesophilic digestion followed. Our results suggest that the selection of the pre-treatment duration as well as the temperature of the subsequent anaerobic step for sludge stabilization should depend on the ratio of primary to secondary sludge.     

污泥堆肥动力学分析及工程启示

主要分析了堆肥体中物料的固、液、气三相及其界面的反应和传质过程,从微观动力学角度进行模拟计算,并分析了堆体内的反应、传质和传热过程,由此揭示污泥堆肥过程的影响因素及相互关系。通过计算分析堆肥过程动力学的控制因素,提出污泥堆肥工程优化的原则。     

城市污泥堆肥过程自动测控系统及其应用

针对城市污泥堆肥过程控制存在的问题,设计开发了一套自动测控系统(CTB),并进行了应用研究。结果表明,与简单定时控制相比,CTB堆肥自动测控系统可缩短堆肥时间28%,使有机物降解更加充分,堆肥产品质量得以提高。     

S-TE污泥好氧减量技术的研究与应用

简述了生物嗜热酶溶解（S—TE）污泥减量技术的原理、嗜热菌的特性和优选、污泥溶解和后续污水污泥处理集成工艺（好氧减量和厌氧产气）的主要影响因素,介绍了近年来S—TE技术应用的最新研究理论和试验成果,并提出了研究和应用中亟待解决的问题。相对于臭氧氧化、氯氧化、热水解、机械破碎、超声波和投加酶等方法,S-TE技术更经济高效、安全,而且能耗低、易于控制,结合后续工艺不仅可以实现污泥的“零排放”,还可同时实现污染物的高效生物降解或沼气产能的增加,应用前景良好。