水葫芦厌氧发酵工艺与现场中试研究

水葫芦生态爆发导致了一系列的生态、环境和社会问题.而水葫芦厌氧制能具有能源回收利用、无污染、残渣可作为肥料的特点,具有很大的发展价值.首先,以水葫芦为原料进行了一系列的厌氧消化实验室试验,主要包括水葫芦自然酸化试验,污泥接种程度试验,高温消化试验,颗粒破碎程度试验,混合堆沤加料试验,两相消化试验.其次,进行了20一规模的中试厌氧消化反应器的设计和运行研究.     

剩余污泥温度分级-生物分相(TSBP)厌氧消化系统运行研究

在厌氧消化阶段理论指导下,开发了温度分级-生物分相(TSBP)工艺,通过控制温度和停留时间来实现温度分级和产酸菌、产甲烷菌生物相分离。结果表明TSBP系统中,停留时间为4d的产酸反应器的溶解性COD浓度、挥发酸积累量、水解率都高于停留时间为2d的反应器,分别能达到5.2g/L、4.7g/L、22.6%。与传统中温单相系统相比较,控制产酸相反应器在45℃下停留时间为4d,产甲烷相反应器35℃下停留16d时,TSBP厌氧消化系统运行较优,其甲烷产量和VS去除率分别为754mLCH4/d和51.29%,高于传统中温单相系统的408mLCH4/d和46.04%。反应器内微生物相扫描电镜的结果显示TSBP系统能提供产酸菌和产甲烷菌各自适宜的生长富集条件,成功实现了两者的基本分离,能够提高厌氧消化效率。     

用正交试验法确定两相厌氧消化的主要影响因素

一、前言厌氧生物法处理有机废水近十多年来又重新引起人们的兴趣,主要原因是为了节能和节省投资。为此,在传统消化基础上,提出了许多厌氧的改进工艺,主要有厌氧接触消化、厌氧滤池、上流式厌氧污泥床和两相     

正确的政策导向是发展可持续污泥处理技术的保障

对污泥厌氧消化技术在国内外的应用及发展情况作了简单介绍.通过与其他污泥处理工艺对比,分析了污泥厌氧消化的优缺点、污泥厌氧消化工艺的费用与收益.指出污泥厌氧消化工艺是一种可持续的实用技术,理应成为城市污水处理厂污泥稳定化处理的首选工艺.认为应对现行的《城市污水处理及污染防治技术政策》进行修改,鼓励有条件的污水处理厂在选择污泥处理工艺时优先考虑厌氧消化技术.     

两相厌氧处理湿式氧化后剩余污泥的研究

针对工业废水剩余污泥可生化性差、处理费用高等问题,以石油化工废水剩余污泥为研究对象,进行了湿式氧化后两相厌氧处理的研究。即剩余污泥经温和的湿式氧化预处理后,有机物从微生物体内释放出来并转移到液相,上清液采用两相厌氧处理。系统研究了两相厌氧中 COD_(Cr)、产气量、BOD_5、N、SO_4~(2-)的变化,以及水力停留时间对处理效率的影响,对影响两相厌氧的主要因素讲行了分析。     

我国城市污水处理厂污泥产沼气的前景分析

污泥厌氧消化具有稳定污泥和回收能量以及处理后污泥可作农肥的突出优点.我国城市污水处理厂污泥多,污泥厌氧消化的推广空间巨大.污泥厌氧消化推广的主要问题是规模较小、投资高、技术复杂、维修量大等,而沼气利用不理想大大削弱了该工艺的优势.必须降低投资、简化运行和提高沼气利用的效益,加速研究配套政策,才能改变投入高、产出低的现状,才能使污泥厌氧消化成为污泥处理的首选工艺.     

热水解厌氧消化工艺的分析和应用探讨

热水解厌氧消化工艺可提高污泥的水解效果和有机物降解率,增加沼气产量;杀灭污泥中病菌;缩短厌氧消化的停留时间、提高消化池内的污泥浓度,节省占地面积和土建工程投资;同时使消化后的污泥易于脱水,污泥体积减少。与传统的厌氧消化工艺比较,热水解厌氧消化工艺强化了污泥的减量化、稳定化、无害化和资源化的处理目标,当与后续热干化工艺结合时,可降低运行成本。从热水解技术的原理和形式出发,结合实际工程方案,对热水解厌氧消化工艺的可行性和应用中的问题进行了初步探讨。     

研究生论文摘要

水葫芦厌氧发酵工艺与现场中试研究 研究生:曹伟华 导师:赵由才 (同济大学环境科学与工程学院 200092) 水葫芦生态爆发导致了一系列的生态、环境和社会问题。而水葫芦厌氧制能具有能源回收利用、无污染、残渣可作为肥料的特点,具有很大的发展价值。首先,以水葫芦为原料进行了一系列的厌氧消化实验室试验,主要包括水葫芦自然酸化试验,污泥接种程度试验,高温消化试验,颗粒破碎程度试验,混合堆沤加料试验,两相消化试验。其次,进行了20m3规模的中试厌氧消化反应器的设计和运行研究。     

复合生物反应器对焦化废水中典型污染物处理特性的研究

采用厌氧缺氧好氧工艺，并在好氧段投入球形填料形成复合反应器处理焦化废水，重点对好氧复合反应器中两相污泥的污染物降解活性进行了比较。试验结果表明好氧复合反应器中附着相污泥浓度高于悬浮相污泥浓度；附着相污泥对焦化废水中苯酚、喹啉和氨氮三种代表性污染物的降解能力和抗抑制性能力均高于悬浮相污泥。     

城市垃圾厌氧消化技术研究

城市垃圾厌氧消化技术研究硕士生：张光明导师：俞珂（清华大学环境工程系１０００８４）本文分别采用间歇试验和连续试验两种方式，进行了高固体厌氧消化工艺处理城市垃圾的工艺和机理研究，得到了城市生活垃圾经过厌氧消化后的处理效果数据、反应动力学参数、反应器的处...     

城市生活垃圾厌氧消化技术进展

简要介绍城市生活垃圾的来源、成分及现有的一些处理方法,并着重介绍城市生活垃圾的厌氧消化处理技术的原理、基本过程,以及影响厌氧消化的因素。最后介绍厌氧消化技术在国内国外的研究现状及进展。     

Autogenerative high pressure digestion: anaerobic digestion and biogas upgrading in a single step reactor system

Conventional anaerobic digestion is a widely applied technology to produce biogas from organic wastes and residues. The biogas calorific value depends on the CH, content which generally ranges between 55 and 65%. Biogas upgrading to so-called 'green gas', with natural gas quality, generally proceeds with add-on technologies, applicable only for biogas flows > 100 m3/h. In the concept of autogenerative high pressure digestion (AHPD), methanogenic biomass builds up pressure inside the reactor. Since CO2 has a higher solubility than CH4, it will proportion more to the liquid phase at higher pressures. Therefore, AHPD biogas is characterised by a high CH4 content, reaching equilibrium values between 90 and 95% at a pressure of 3-90 bar. In addition, also H2S and NH3 are theoretically more soluble in the bulk liquid than CO2. Moreover, the water content of the already compressed biogas is calculated to have a dew point <--10 degrees C. Ideally, high-quality biogas can be directly used for electricity and heat generation, or injected in a local natural gas distribution net. In the present study, using sodium acetate as substrate and anaerobic granular sludge as inoculum, batch-fed reactors showed a pressure increase up to 90 bars, the maximum allowable value for our used reactors. However, the specific methanogenic activity (SMA) of the sludge decreased on average by 30% compared to digestion at ambient pressure (1 bar). Other results show no effect of pressure exposure on the SMA assessed under atmospheric conditions. These first results show that the proposed AHPD process is a highly promising technology for anaerobic digestion and biogas upgrading in a single step reactor system.     

Ultrasonic sludge treatment for enhanced anaerobic digestion.

Ultrasound is the term used to describe sound energy at frequencies above 20 kHz. High-powered ultrasound can be applied to a waste stream via purpose-designed tools in order to induce cavitation. This effect results in the rupture of cellular material and reduction of particle size in the waste stream, making the cells more amenable to downstream processing. sonix is a new technology utilising high-powered, concentrated ultrasound for conditioning sludges prior to further treatment. This paper presents recent results from a number of demonstration and full-scale plants treating thickened waste activated sludge (TWAS) prior to anaerobic digestion, therefore enhancing the process. The present studies have proved that the use of ultrasound to enhance anaerobic digestion can be achieved at full scale and effectively result in the TWAS (typically difficult to digest) behaving, after sonication, as if it were a "primary" sludge. The technology presents benefits in terms of increased biogas production, better solids reduction, improved dewatering characteristics of the digested sludge mixture and relatively short payback periods of two years or less subject to the site conditions and practices applicable at that time.     

A hydrogen-based variable-gain controller for anaerobic digestion processes.

An easy-to-implement controller based on gas phase measurements for anaerobic digestion processes was developed. The controller is based on the indirect control of COD in the effluent by means of controlling the hydrogen concentration in the biogas. The fast response of hydrogen under destabilizations, such as those caused by overloads, guarantees an early actuation on the system before it destabilizes. The controller is designed such that it brings the anaerobic digestion process to maximum capacity by pushing it to maximum methane production as long as hydrogen remains low. Experiments have been conducted to test the controller under organic over- and underload situations and promising performance was achieved. Further experiments must be carried out to validate the controller under a wider spectrum of situations to enable its robust industrial application.     

Study of the biological N removal over nitrite in a physico-chemical-biological treatment of digested pig manure in a SBR.

SBR technology is used to treat the supernatant from mesophilic anaerobic digestion of piggery wastewater. The novelty of the treatment consists in the use of a final coagulation/flocculation step inside the SBR cycle to reach the legal COD effluent standard. The pH changes introduced by the use of FeCl(3) do not affect the nitrifying activity. The SBR treatment includes a strategy to the control of oxygen supply and ammonia concentrations inside the digester to favor the biological nitrogen removal over nitrite, which makes the process more economical. The influence of several of these parameters on the AOB biomass activity is studied in this paper.     

Application of metaproteomic analysis for studying extracellular polymeric substances (EPS) in activated sludge flocs and their fate in sludge digestion

Metaproteomic analysis, comprising protein separation and identification, was applied to study extracellular proteins in activated sludges and to track their fate in sludge digestion under both anaerobic and aerobic conditions. The complex sludge proteins were first separated by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and further analysed by liquid chromatography tandem mass spectrometry (LC-MS/MS) to search their identification. Base extraction and cation exchange resin (CER) method were used to extract EPS from sludges at 0, 12 and 30 days of batch digestion. Several important observations were made during this study. Firstly, protein bands were well separated by extraction/SDS-PAGE protocol used in this study. Secondly, numerous protein bands remained after digestion, indicating that these proteins are not easily degradable in sludge digestion. Thirdly, protein bands detected following anaerobic and aerobic digestion differed, suggesting that proteins degraded in two different digestion environments are not the same. Finally, protein bands that emerged distinctively following anaerobic digestion was found to be subunits of methyl-coenzyme M reductase, the enzyme involved in methane generation, in Methanosarcina barkeri. These results demonstrated that metaproteomic investigation on activated sludge EPS is useful for studying floc formation in activated sludges and their degradation in various digestion environments.     

Full-scale application of anaerobic digestion process with partial ozonation of digested sludge.

For improving sludge digestion and biogas recovery, a new anaerobic digestion process combined with ozonation was tested at a full-scale unit for 2 years and its performance was compared with a simultaneously operated conventional anaerobic digestion process. The new process requires two essential modifications, which includes ozonation for enhancing the biological degradability of sludge organics and concentrating of solids in the digester through a solid/liquid separation for extension of SRT. These modifications resulted in high VSS degradation efficiency of ca. 88%, as much as 1.3 times of methane production and more than 70% reduction in dewatered sludge cake production. Owing to accumulation of inorganic solids in the digested sludge, water content of the dewatered sludge cake also reduced from 80% to 68%. An energy analysis suggested that no supplemental fuel was necessary for the subsequent incineration of the cake from the new process scheme. The process is suitable to apply to a low-loaded anaerobic digestion tank, where power production is used.     

Sludge pre-treatment with pulsed electric fields.

The anaerobic stabilization process depends - among other things - on the bio-availability of organic carbon. Through pre-treatment of the sludge which leads to the destruction of micro-organisms and to the setting-free of cell content substances (disintegration), the carbon can be microbially converted better and faster. Moreover, effects on the digestion are likely. However, only little experience is available in sludge treatment with pulsed electric fields. Laboratory-scale digestion tests have been run to analyse the influence of pulsed electric fields on the properties of sludge, anaerobic degradation, sludge water reload and foaming of digesters. The results will be compared with those of other disintegration methods (high pressure homogeniser, thermal treatment). The effect of pre-treatment on the sludge is shown by the COD release. Degrees of disintegration have been achieved up to 20%. The specific energy input was high. The energy consumption has been decreased by initial improvements (pre-heating to 55 degrees C). The filament bacteria were partially destroyed. The foam reduction in the digesters was marginal. The anaerobic degradation performance has been improved in every case. The degradation rate of organic matter increased about 9%. Due to the increase of degradation, there is a higher reload of the sludge-water with COD and nitrogen compounds.     

Fate of nonylphenol polyethoxylates and nonylphenoxy acetic acids in an anaerobic digestion process for sewage sludge treatment.

Many environmental problems caused by endocrine disruptors (EDs) have been reported. It is reported that EDs flow into sewage treatment plants, and it has been pointed out that these may be shifted from the wastewater treatment process to the sludge treatment process. Little is known about the fate of EDs accumulated in sewage sludge, so we carried out a study to clarify the fate of EDs in sewage sludge treatment processes, especially in an anaerobic digestion process. In this study, nonylphenol (NP) was selected as a target ED. Nonylphenol ethoxylates (NPnEO) or nonylphenoxy acetic acids (NPnEC), which were the precursor of NP, were added to an anaerobic digestion process, and mass balance was investigated. The following results were obtained from the anaerobic digestion experiments. (1) NP1EO was injected to an anaerobic digestion testing apparatus that was operated at a retention time of approximately 28 d and a temperature of 35 degrees C with thickened sludge sampled from an actual wastewater treatment plant. Approximately 40% of the injected NP1EO was converted to NP. (2) NP1EC was injected to an anaerobic digestion testing apparatus with thickened sludge. As a result, almost all injected NP1EC was converted to NP. When NP2EC was injected, NP2EC was not converted to NP until the 20th day.