为增强污泥消化的超声波污泥预处理

近几十年来,厌氧消化工艺得到广泛的研究,而强化这种工艺的各种方法亦得到了探讨。这些方法包括热处理、添加碱、分阶段和膜强化。一般说来,这些方法在技术上行得通,而却未能证明在经济上有竞争力。     

超声波联合化学调理改善污泥脱水性能研究及应用

由于超声波技术和化学调整技术对污泥脱水具有良好的改善作用,为此提出超声波联合化学调理改善污泥脱水性能研究及应用.通过对超声波联合化学调理改善污泥脱水性能进行测试分析表明,超声波联合化学调理可以改善污泥脱水性能,在应用过程中需要控制超声时间和化学剂量.     

超声波促进污泥厌氧消化的研究

介绍了超声波的作用机理，指出在污泥厌氧消化过程中，污泥水解是限速步骤，在厌氧消化前，对污泥进行超声波破解预处理，促使细胞壁破裂，细胞内含物溶出，可以加速污泥的水解过程，从而达到缩短消化时间，减少消化池容积，提高沼气产量的目的。     

零污泥排放处理新技术及应用

根据目前常规的活性污泥处理的方法都存在投资大、处理成本高等各种问题,本文介绍了剩余污泥可溶化回流氧化处理技术及其尚待改进的问题.并重点列举了臭氧、超声波法处理剩余污泥工艺的应用实例和研究现状.为达到污泥零排放的目的并能从本质上减少污泥排放量提出了未来的发展方向和研究方向.     

污泥深度脱水技术现状与发展趋势

随着我国社会经济的持续发展,以及城市化进程的加快,越来越多人涌入大城市,城市污泥产量增长十分迅速,进而产生了不少环境问题。如何有效地处置污泥,降低污泥对环境的消极影响,实现对污泥的综合利用,这是一个必须要考虑的时代问题。分析污泥深度脱水的意义及其面临的问题,并探讨污泥深度脱水技术现状与发展趋势,旨在合理处置污泥,保护城市生态环境,推动人类社会的良好发展。     

规模化猪场厌氧消化污泥脱水工艺研究

规模化猪场厌氧消化污泥堆肥是消化污泥处置的最重要途径之一,而作为污泥堆肥的重要预处理环节,消化污泥脱水却一直是道难题,文章就如何选择合理的污泥脱水工艺展开深入探讨.研究表明,规模化猪场消化污泥具有相对密度小、比阻大、有机养分含量高等特点,运用机械方法脱水不但费用高,而且技术上难度大,还会破坏消化污泥原本的有机养分组成,降低其堆肥后的农用的价值;和机械脱水方法相比,自然脱水方法在经济上具有明显的优势,而且技术上也可行.最后,文章认为污泥干化床工艺是自然脱水方法中较为理想的厌氧消化污泥脱水工艺.     

污泥减量化与处理处置技术研究与应用现状

从现阶段污泥问题出发,对国内外有关污泥减量化、污泥处理与处置方面的研究成果与应用现状进行了阐述,介绍了各种技术的优缺点,并对未来污泥减量技术与处理处置技术的发展进行展望。     

污泥碳化技术应用现状及展望

随着城市污水污泥排放量的逐年上升,污泥碳化技术发展迅速。文中分析了城市污泥的碳化机理,简述了几种主要污泥碳化技术工程应用现状,着重介绍了污泥碳化技术发展趋势,旨在为城市污泥碳化工艺设备的开发和研究提供参考。     

我国污水处理厂污泥处理现状分析——以大连夏家河污泥处理厂为例

对我国污泥处理的现状进行阐述,重点介绍大连市夏家河污泥处理厂的处理工艺,并分析其特点,最后提出对我国现阶段污泥处理的建议。     

超声波预处理对污泥干燥速率影响研究

在超声波预处理污泥干燥实验基础上,分析了超声波预处理技术对污泥干燥速率的影响,并对污泥干燥过程进行了指数拟合,结果表明.超声波预处理能有效提高污泥干燥效率,其改善的程度取决于不同的实验条件;超声波预处理能够加速表面自由水分蒸发和快速结束污泥恒速干燥阶段;增大超声波功率可以更好地改善污泥的干燥特性,但改善的程度随着十燥时间的延长而放缓;超声波处理时间过长可能会增大污泥的黏度,反而不利于污泥脱水干燥.     

超声波制备生物柴油技术的研究进展

超声波技术作为一门新兴的技术已受到普遍关注.文章综述了近年来国内外超声波技术在生物柴油制备中应用的研究现状、制备原理和优缺点,指出了该技术在生物柴油制备中须要解决的问题,在此基础上提出超声波制备生物柴油技术的发展方向,认为开发更优良的的制备工艺是今后超声波制备生物柴油技术研究领域的主要任务.     

Heat and energy requirements in thermophilic anaerobic sludge digestion

The heating requirements of the thermophilic anaerobic digestion process were studied. Biogas production was studied in laboratory experiments at retention times from 1 to 10 days. The data gathered in the experiments was then used to perform a heat and energy analysis. The source of heat was a conventional CHP unit system. The results showed that thermophilic digestion is much faster than mesophilic digestion and therefore produces more biogas in a shorter time or at smaller digester volumes. The major part of the heating requirements consisted of sludge heating. The heat losses of the digester were only 2–8% of the sludge heating requirements. The heating requirements in thermophilic digestion are about twice those of mesophilic digestion. Therefore a CHP unit system cannot cover all of the needs for successful operation of thermophilic digestion. Heat regeneration was introduced as a solution. Heat is regenerated from the sludge outflow at a temperature of 50–55 °C and transferred to the cold inflow sludge at a temperature of 11 °C. Enough heat is regenerated in a conventional counter flow heat exchanger to bring the thermophilic process to the same level as the mesophilic one. Considering the smaller digester volumes and the relatively small investment in the regenerative equipment, the construction of thermophilic digestion systems may be a very good alternative to conventional mesophilic sludge digestion systems.     

Influence of residual moisture on deep dewatered sludge pyrolysis

Wet sewage sludge pyrolysis is an attractive method for producing H₂-rich fuel gas. To reduce energy consumption for excess moisture evaporation, deep dewatered sludge was used instead of traditional high-moisture sludge in this study. The emphasis was placed on elucidating the effects of residual moisture on tar, char, and on syngas generation, and clarifying the mechanisms involved. Results show that residual bound water exerted a stronger influence on products yields and distributions than free water, since the former could work inside sludge particles while the later only acted as steam outside. At low temperature (873 K), sludge moisture increased the relative ratio of cyclic, unsaturated, and hydroxyl, aldehyde or carboxyl-containing compounds in tar, in whose generation process H₂ and carbonaceous gas were produced. When the temperature rose, water in sludge increased the surface area of the char. The breaking of C–C bonds caused by residual moisture would promote the macromolecular organic matters conversion to smaller ones, which were easy to undergo steam gasification, thus giving rise to the transformation of char–C to gas–C and enhancing H₂ yield. Therefore, the production of syngas, containing large amounts of H₂ and CO, was improved efficiently.     

Effect of ultrasonic treatment of digestion sludge on bio-hydrogen production from sucrose by anaerobic fermentation

The utilization of ultrasonic treatment on digestion sludge to enhance microbial activity for bio-hydrogen production was investigated. The optimal conditions of ultrasonic time and density on digestion sludge were detected using Central Composite Experimental Design. The regression analysis showed that a significant increase of 1.34 fold in bio-hydrogen production rate could be obtained when ultrasonic time was 10 s and ultrasonic density around 130 W/l at digester sludge concentration of 15 g VSS/l. The analyses of biodegradation characteristics in bio-hydrogen producing process implied that ultrasound did not denature the digestion sludge but just improved its biodegradation efficiency. In order to find out the mechanism of ultrasonic treatment on digestion sludge, a control experiment was designed and COD values of digestion sludge in different treatment conditions was measured.     

菜籽油超声波法制备生物柴油的研究

以菜籽油和甲醇为反应原料,以KNO3/Al2O3为催化剂,采用超声波法制备生物柴油,考察了超声波频率、醇油物质的量比、催化剂用量等条件对反应的影响。试验结果表明,该反应的最佳条件:超声波频率为30kHz,醇油物质的量比为7∶1,催化剂用量为菜籽油质量的2.0%。在此条件下,生物柴油产率为94%。所得生物柴油的主要性能指标均符合德国的生物柴油标准。     

Principles and potential of the anaerobic digestion of waste-activated sludge

When treating municipal wastewater, the disposal of sludge is a problem of growing importance, representing up to 50% of the current operating costs of a wastewater treatment plant. Although different disposal routes are possible, anaerobic digestion plays an important role for its abilities to further transform organic matter into biogas (60–70 vol% of methane, CH₄), as thereby it also reduces the amount of final sludge solids for disposal whilst destroying most of the pathogens present in the sludge and limiting odour problems associated with residual putrescible matter. Anaerobic digestion thus optimises WWTP costs, its environmental footprint and is considered a major and essential part of a modern WWTP. The potential of using the biogas as energy source has long been widely recognised and current techniques are being developed to upgrade quality and to enhance energy use. The present paper extensively reviews the principles of anaerobic digestion, the process parameters and their interaction, the design methods, the biogas utilisation, the possible problems and potential pro-active cures, and the recent developments to reduce the impact of the problems. After having reviewed the basic principles and techniques of the anaerobic digestion process, modelling concepts will be assessed to delineate the dominant parameters. Hydrolysis is recognised as rate-limiting step in the complex digestion process. The microbiology of anaerobic digestion is complex and delicate, involving several bacterial groups, each of them having their own optimum working conditions. As will be shown, these groups are sensitive to and possibly inhibited by several process parameters such as pH, alkalinity, concentration of free ammonia, hydrogen, sodium, potassium, heavy metals, volatile fatty acids and others. To accelerate the digestion and enhance the production of biogas, various pre-treatments can be used to improve the rate-limiting hydrolysis. These treatments include mechanical, thermal, chemical and biological interventions to the feedstock. All pre-treatments result in a lysis or disintegration of sludge cells, thus releasing and solubilising intracellular material into the water phase and transforming refractory organic material into biodegradable species. Possible techniques to upgrade the biogas formed by removing CO₂, H₂S and excess moisture will be summarised. Special attention will be paid to the problems associated with siloxanes (SX) possibly present in the sludge and biogas, together with the techniques to either reduce their concentration in sludge by preventive actions such as peroxidation, or eliminate the SX from the biogas by adsorption or other techniques. The reader will finally be guided to extensive publications concerning the operation, control, maintenance and troubleshooting of anaerobic digestion plants.     

Thermophilic digestion of waste-activated sludge coupled with solar pond

Thermophilic anaerobic digestion (AD) is an efficient treatment process for waste activated sludge with enhanced hydrolysis and digestion rates. However, the costs associated with maintaining high temperature for thermophilic digester should be minimized and the thermal stability of the reactor should be maximized for its practical use. This study tested an integrated system consisting of a solar pond and an AD reactor for digestion of waste activated sludge. The integrated system could be stably operated at 51.6 ± 1.5 °C in sunny days (and nights) and maintained digestion performance over at least three days with cloud and rain. On the contrary, the control reactor without solar pond experienced significant temperature fluctuation and poor digestion performance. After 29d, the integrated system thermophilic reactor removed 65.0 ± 4.2% of total chemical oxygen demands and produced 79% excess biogas. The concentrations of soluble chemical oxygen demand, protein and saccharides in digester with solar pond were higher than those in that without the pond. Also, the presence of solar pond enhanced hydrolysis and degradation of soluble microbial byproduct-like compounds with carboxylic groups and amide-2 groups in sludge.