THE EFFECTS OF IMPROVING SEWAGE SLUDGE DIGESTION

A model was developed and tested to investigate the effects of various parameters on the processing costs of anaerobic digestion. The model was based on empirical data collected from full-scale plants which varied in size from 35,000 to 900,000 population equivalents. (Equivalent to loading rates of 0.5 to 2.7 kg VS/m³/d.) In spite of different operating regimes and conditions of the plants analysed, various relationships were discovered between: sludge quality and volatile solids destruction; sludge quality and biogas yield; and, effluent volatile solids and dewatering. Where correlations existed, these were used to make predictions on operating costs of the digestion and dewatering plant based on sensitivity analysis. The results of the model were used to make recommendations on how to optimise the operation of an anaerobic digestion plant.     

新型复合固化剂固化淤泥效果试验研究

淤泥固化技术可以实现淤泥的资源化利用,有望解决近年来日益严重的疏浚淤泥处置问题。在传统固化剂如石灰、水泥的基础上,探索更有效、低廉的固化剂是很有必要的。本文通过室内试验,将一种新型复合固化剂和水泥、石灰的固化效果进行了对比分析,从淤泥固化土的土颗粒粒径组分及抗压强度角度比较了新型固化剂的效果,结果表明,新型固化剂的固化效果优于传统固化剂水泥和石灰。     

EFFECTIVE DESIGN OF GAS-MIXING SYSTEMS FOR THICK SLUDGE DIGESTION: TWO CASE STUDIES

In the UK and elsewhere, advances in the design of anaerobic mesophilic digesters have resulted in a trend towards the digestion of thicker sludges. This includes a number of new facilities using 'bolt-on' technologies such as thermal hydrolysis, pre-pasteurisation and enzymic hydrolysis. Thermal hydrolysis utilises thickened sludge, and the digester is fed with a high dry-solids content (typically 12%), thereby intensifying the digestion process and reducing reactor volumes. However, there is limited experience in the design of digester mixing systems for such applications. As the trend continues towards advanced digestion technology, more emphasis will be placed on the basic unit process operation of mixing.
This paper describes the design of a gas-mixing system for thick feed sludges for two full-scale plants at Mogden and Aberdeen. Mogden is a refurbishment project and Aberdeen is a newly constructed plant.     

THE USE OF REED-BEDS FOR SLUDGE DRYING

This paper reviews the design and performance experience with sludge-drying reed-beds over the past fourteen years. Whilst there are very few of these systems in the UK, there is much experience in Europe and particularly in Denmark. The Danish experience is reviewed in some detail. The design of and experience gained from two UK systems is described. The final dry-solids concentration depends upon the concentration in the initial sludge dose. It is possible, when treating anaerobically digested sludges containing 3–4% DS, to achieve about 90% volume reduction and a final dry-solids content of up to 40%. With thinner activated sludges containing 0.3–0.6% DS, a reduction (in volume) of greater than 97% is possible with a final solids concentration in the range 10–20%.     

CONTROLLING AND MONITORING ANAEROBIC DIGESTERS FED WITH THERMALLY HYDROLYSED SLUDGE

A sludge treatment centre has been constructed at Nigg sewage-treatment works, Aberdeen to receive sewage sludge from a number of plants in the area. The sludge is treated to the USEPA Class A standard in a thermal-hydrolysis plant in which it is heated to 165°C for 30 mins in batch reactors. The hydrolysed sludge, which contains 10–12% dry solids, is then pumped to an anaerobic digestion plant where the temperature is maintained at 39°C for a minimum of 15 days.
The commissioning and testing of the anaerobic digesters was different to those which are fed with untreated sludge, and the approach is outlined. The paper discusses (a) the digestion parameters which were monitored during start-up, (b) the performance of the digesters throughout the commissioning and testing period, and (c) the quality of the dewatered sludge.     

曝气方式对好氧颗粒污泥性能的影响

好氧颗粒具有良好的沉降性能、较高的生物量和高容积负荷条件下降解高浓度有机废水的良好生物活性,是提高生物反应器效能的重要物质。与传统的活性污泥法相比,可简化工艺流程、减少污水处理系统的容积和占地面积、降低投资和成本。随着对好氧颗粒污泥研究的不断深入,将好氧颗粒污泥应用于实际污水处理得到越来越多的关注。文中以校园生活污水为处理对象,在SBR反应器中接种絮状污泥,通过增加曝气头个数,在低表观气速的前提下成功培养出稳定的好氧颗粒污泥,MLSS达7000mg·L-1左右,SVI最终稳定在38ml·g-1,COD、P、NH3-N的去除率分别达到89%、87.81%、98.72%,说明好氧颗粒污泥对实际生活污水具有较好的处理效果,并且达到了节约能源的目的。     

搅拌站污泥对混凝土力学性能和耐久性的影响

混凝土搅拌站污泥作混凝土掺合料可有效提高其利用率。通过对污泥取代粉煤灰试件进行水泥胶砂试验,评价了污泥的活性,并研究了污泥对混凝土力学性能和耐久性的影响。结果表明,搅拌站污泥活性较低,如污泥取代粉煤灰比例不超过30%,则不会对混凝土抗压强度和耐久性产生不利影响。     

污水厂污泥作吸附剂的试验研究

将太原市杨家堡污水厂初沉泥、剩余污泥及分别加工后所得产物用作吸附剂对污水进行处理，发现这四种“炭除了对ＮＨ３－Ｎ几乎都无作用外，对ＣＯＤ，Ｆ＾－及Ｃｄ＾２＋都有不同程度的去除能力。当投”炭“量为１－６ｇ／Ｌ时，Ａ＾＃对ＣＯＤｃｒ的去除率相应达３８－７０％。     

Mesophilic and thermophilic anaerobic digestion of faecal sludge in a pilot plant digester

In many developing countries, the sewage consisting of faecal sludge is discharged untreated into rivers, lakes and coastal areas. This poses a health hazard and a risk to the ecosystem, and wastes a resource which could produce sustainable energy. This paper reports results from an anaerobic digester of 1000L used for digestion of faecal waste at mesophilic and thermophilic conditions. The specific biogas production rate from faecal sludge was in the range of 0.06–0.12 m³/(kg DM.d) at mesophilic conditions at NTP (Normal Temperature & Pressure i.e. 25 °C and 1 atm. Pressure) and 0.1–0.21 m³/(kg DM.d) at thermophilic conditions calculated at NTP. The number of toilet users affects the biogas production with changes in the organic loading rate. The results showed 97% reductionin chemical oxygen demand and 90% reduction in biological oxygen demand of anaerobic digester discharge water as compared to inlet substrate values.     

利用东湖淤泥制备超轻陶粒的研究

利用东湖淤泥为主要原材料,进行堆积密度小于500kg/m3超轻陶粒研制。结果表明:按照发泡组分与东湖淤泥比例为20%∶80%,600℃预烧15min,1180℃焙烧12min,制备出了筒压强度1.7MPa、吸水率13.4%、堆积密度为485 kg/m3超轻陶粒。     

谈污泥厌氧消化预处理方法

结合传统的污泥厌氧消化周期长、消化速率低的特点,综述了热、化学、生物和机械预处理方法及其在研究中对污泥厌氧消化的影响,并提出厌氧消化预处理方法的展望,以期改善污泥理化性质,提高厌氧消化效率。     

污泥减量化处理新工艺ExelysTM技术及其应用

介绍了连续式污泥热水解工艺——ExelysTM工艺的系统构成和工艺原理,并结合实际工程说明其工艺优越性。工程实践表明,污泥热水解技术是一种污泥减量化程度高、能源回收率大、安全可靠、清洁和环保的污泥处理工艺。     

SLUDGE TREATMENT AND DRYING REED BED SYSTEMS IN DENMARK

Sludge Reed beds have been used for dewatering (draining and evapotranspiration) and mineralisation of sludge in Denmark since 1988 when the first sludge processing system was introduced. Sludge from wastewater treatment plants (2,500-125,000 pe) is treated in sludge reed bed systems with 1–18 basins with loading rates of 25–2,200 tonnes dry solids/year for ten years. In 2002, approximately 95 systems were in operation. Dimensioning and design of reed bed systems depends on the sludge production rate, sludge type, quality and regional climate.
The maximum sludge loading rate is approximately 50–60 kg DS/m²/year. Loading cycles are related to the sludge type and the age of the sludge reed systems. The sludge residue will, after approximately ten years of operation, reach an approximate height of 1.2–1.5 metres with dry solids content of 30–40%. Experience has shown that the quality of the final product with respect to heavy metals, hazardous organic compounds and pathogen removal after ten years of treatment make it possible to recycle the biosolids to agriculture as an enhanced treated product.     

污泥减量化处理新工艺Biothelys~(R)技术及其应用

介绍了污泥热水解预处理技术在促进细胞固体溶解、减小污泥粘滞性等方面的特性,着重阐述了Biothelys~工艺的系统构成、工艺原理及其优越性,并结合工程运行实例对比分析了Biothelys~工艺在污泥减量、减小设备体积和能量回收等方面的技术优势。工程实践证明,Biothelys~是一种污泥减量化程度高、能源回收率大、安全可靠、清洁和环保的污泥处理工艺。     

城市污泥合成燃料的应用研究

提出了城市污水处理厂污泥最终处置的一种新方法－合成燃料法。介绍了污泥燃料的合成及其在普通工业锅炉中燃用的热工测试、环保测试、跟踪试验的情况。     

热水解污泥的厌氧消化试验研究

先用热水解对污泥进行预处理，然后进行厌氧消化试验。结果表明，最适宜的热水解温度为170℃、反应时间为30min；经热水解污泥的厌氧消化性能和系统的处理效率都得到显著提高，COD去除率最大时提高了20．18％，日均产气量则增加了79．20％～99．55％。     

全面考虑次内力影响的预应力混凝土框架施工过程研究

以东方体育中心大跨预应力混凝土框架梁为研究背景,通过对3种施工方案的模拟分析,得出不同施工方法对结构开裂弯矩、裂缝宽度、跨中挠度以及结构极限承载力的影响。最后对合理调整预应力混凝土框架结构次内力的施工方法进行探讨。     

透气真空快速泥水分离技术对淤泥水分的促排作用

 透气真空快速泥水分离技术适用于高含水率高黏粒含量疏浚淤泥的堆场处理,可快速减小堆场中淤泥的体积,加速堆场的周转利用,并能解决常规真空处理方法中存在的滤层淤堵问题。通过自行研制的室内模型试验装置,进行透气真空快速泥水分离和自然静置泥水分离的室内模型对比试验,可以看出透气真空快速泥水分离技术对淤泥中水分有促排作用,不仅能快速通过滤层管道抽吸出大量水分,而且其表面水增厚速度也大于自然静置下的增厚速度。透气真空技术中淤泥存在2个排水面,土颗粒与孔隙水存在渗流作用,渗流使得固相与液相产生相对运动。相对渗流使得土颗粒受到拖拽力的作用,拖拽力的大小和方向与相对渗流中的等速界面有关。在拖拽力作用下,淤泥内部会发生“胶结—断裂”压缩过程并产生“稀薄”效应,使得淤泥骨架的体积压密速度大于抽出孔隙水体积速度,进而解释透气真空对淤泥促排作用的机制。     

澄清池自动排泥控制技术的研究

在对澄清池排泥过程进行了深入探讨的基础上，提出了一种较合理的排泥监控方法，开发了研制了澄清池自动排泥装置。     

砂岩水物理化学损伤机制研究

通过对不同水环境下砂岩孔隙率、pH值演变和矿物蚀变等开展一系列的试验研究,从微细观层次分析砂岩的水物理化学损伤机制,在此基础上,提出以蒸馏水环境下测得的次生孔隙率为基础,从总次生孔隙率中将水化学作用产生的次生孔隙率分离出来的方法,进而建立基于次生孔隙率变化的砂岩水物理化学损伤变量表达式;另一方面,通过对浸泡180 d时的砂岩试件进行CT扫描,将损伤计算结果与CT检测结果进行了对比分析.研究结果表明,砂岩水物理损伤主要受水流导致的矿物颗粒间胶结物与碎屑运移和扩散影响,与水化学损伤与离子浓度、pH值等水环境变化密切相关;二者所诱发的次生空隙是水物理化学作用影响砂岩力学性质的主要原因;水-岩反应后某一时刻砂岩的总次生孔隙率可由水物理作用和水化学作用产生的次生孔隙率两部分构成.砂岩水物理化学损伤计算结果与CT检测结果的对比分析表明,采用所提出的砂岩损伤变量表达式来描述其水物理化学损伤是可行的.