Effects of Ultrasonic on the Dehydration Function of Sludge and Discussion on Internal Mechanism

[Objective] The aim was to study the effects of ultrasonic on the dehydration function of sludge and internal mechanism.[Method] Taking the residual sludge from a municipal domestic sewage treatment plant as an object,the effects of ultrasonic time and sound energy density on the dehydration function of sludge were studied firstly,then the internal mechanism of improvement of sludge dehydration function by ultrasonic was discussed.[Result] As the increase of ultrasonic time,sludge particles became smaller,and COD of sludge filtrate went up obviously;meanwhile,the capillary suction time (CST) of sludge increased firstly and then decreased,and the minimum value (75.7 s) appeared when ultrasonic time was 8 s.With the raising of sound energy density,the size of sludge particles went down gradually.However,long ultrasonic time and high sound energy density could decrease the dehydration function of sludge.For the possible mechanism of improvement of sludge dehydration function by ultrasonic,ultrasonic adjusted and regrouped sludge,and hydration water in the sludge was released.[Conclusion] The study could provide certain theoretical foundation for the industrial application of ultrasonic.

Preparation and Bloating Mechanism of Porous Ultra-lightweight Ceramsite by Dehydrated Sewage Sludge and Yellow River Sediments

To solve the disposal problems of solid wastes, dehydrated sewage sludge and Yellow River sediments were tested as components for production of ultra-lightweight ceramsite. The effects of Yellow River sediments addition on the characteristics of ceramsite were investigated. Ceramsite with different Yellow River sediments additions was characterized using thermal analysis, X-ray diffraction, morphological structures analyses, pore size distributions and porosity analyses. Chemical components, especially ratios of Si O2 ＋ Al2O3/Flux, were used to explain the glassy shell formation, physical properties and pores distribution of ultralightweight ceramsite; physical forces for instance expansion force and frictional resistance which combined with Si O2 ＋ Al2O3/Flux ratios were used to explain the bloating mechanism. Results showed that the maximum addition of Yellow River sediments for making ultra-lightweight ceramsite was 35%. Macropores（between 0.226 μm and 0.554 μm） of ultra-lightweight ceramsite were dominant in the pore structures of ultra-lightweight ceramsite and its porosity was up to 67.7%. Physical force of expansion force was constant with the variation of Yellow River sediments content and physical force of frictional resistance was decreased with the increase of Yellow River sediments addition. The relationship between expansion and frictional resistance could determine the expansion rate of ceramsite. Larger pores inside the ceramsite bodies could be obtained as Yellow River sediments additions ranged from 10% to 30%. Ceramsite with higher Yellow River sediments additions of 40%（Si O2 ＋ Al2O3/Flux ratios 4.25） became denser and have lower porosity. Crystal components analysis proved that the sintering process made some components of raw materials transfer into other crystals having better thermostability.

Application of Chitosan Flocculant to Conditioning Sludge

The dewaterability of activated sludge conditioned by chitosan flocculant was studied. The effects of chitosan characteristics such as molecular weight, degree of deacetylation, and dose on the dewaterability were investigated. The sludge dewaterability is evaluated in terms of specific resistance to filtration, residual turbidity of supernatant, moisture content of cake, and settling rate. Sludge dehydrating behaviors conditioned with CTS, PAM and PAC flocculants were compared. The conditioning was also carried out with dual flocculants in two stages. It is found that the sludge conditioned with CTS has better dewaterability than that with PAC. The optimum conditions with chitosan are: dose 0.8 - 1.2 g per 100 g dry cake, molecular weight 300,000, and degree of deacetylation 70%. The conditioning in two stages with dual flocculants is found to be more effective than that with single flocculant.

污水处理厂剩余污泥化学预处理技术研究综述

污水处理厂产生大量的成分复杂的污泥,如果不加以妥善处理,将会对环境造成危害。脱水是污泥处理处置中的关键环节。对污水处理厂剩余污泥预处理技术进行了综述,论述了几种化学预处理方法,包括酸/碱预处理、臭氧预处理、Fenton预处理、过硫酸盐预处理、高锰酸盐和高铁酸盐预处理等技术的研究进展,讨论了不同预处理方法对污泥脱水性能的影响。

长江水源水厂脱水污泥资源环境属性探究

研究选取两家长江水源水厂的脱水污泥作为跟踪对象,分析其资源环境属性,为明确其处理处置风险及可行性提供数据支撑。结果表明:两家水厂脱水污泥夏秋季温度高、p H低,冬春季温度低、pH高。通过相关性分析可知,其中有机物含量与进厂原水有机物含量相关性不高,但与含水率相关性较高,可通过测定含水率作为判断其有机物含量高低的依据之一。脱水污泥污染指标及其堆放区域附近大气污染物排放指标基本全面优于各项标准中规定的限值,可应用于多种类型的资源化利用场景。其粒径分布接近黏土、亚黏土或粉砂类,无机组分以SiO_(2),Al_(2)O_(3)和Fe_(2)O_(3)为主,可作为一种类黏土原料,开展广泛的资源化处置。

聚合氯化铝预处理污泥联合脱水有效性及机理

为研究聚合氯化铝对污泥脱水性能的影响及其联合不同脱水手段对污泥脱水性能的提升机理,本文开展了自重脱水、离心脱水和渗析脱水试验,研究发现8%掺量的聚合氯化铝预处理污泥联合渗析脱水的效果最佳。其最佳掺量的预处理污泥的残余含水率可脱水降至36.2%,其重力水、封闭水、包裹水和结合水分别为81.2%、10.2%、7.3%、1.3%。污泥经聚合氯化铝预处理后,其污泥颗粒间距缩小、孔隙减少,无明显大孔隙,结构趋于均一化,结构更紧密,联合渗析脱水处理的聚合氯化铝最佳掺量预处理污泥孔隙率最低降至0.29。推测是由于聚合氯化铝使污泥凝聚成细小而密实污泥颗粒,而这种类骨架的结构有利于渗析力的传递,自由水不断排出,污泥结构继续趋于紧密,促进渗析力在污泥中传递。

复合调理对淤泥机械压滤脱水特性的影响机理分析

机械压滤脱水是广泛应用的河湖淤泥脱水工艺,淤泥调理方式是影响机械压滤脱水效率的关键因素之一,采用聚丙烯酰胺(PAM)为代表的絮凝剂调理以及絮凝剂与无机调理剂联用的复合调理是2种典型的淤泥调理措施。复合调理近年来发展迅速,研究絮凝剂单一调理与复合调理对机械脱水效率的影响、探索作用机理,对淤泥机械压滤脱水的工艺优化具有重要意义。以官田湖底泥为试验对象,对比PAM、新型低碱性淤泥改性剂(LAC)的淤泥调理、脱水效果,分析PAM及PAM+LAC复合调理淤泥脱水工艺参数,利用压汞试验与扫描电镜(SEM)揭示复合调理对脱水泥饼结构影响。结果表明,调理药剂的促进作用主要在过滤脱水阶段最显著;LAC具有替代和强化PAM调理效果的作用,改善了泥饼卸料性能;加入LAC有助于维持泥饼骨架结构和增大泥饼孔隙,增加的孔隙以开口孔隙为主。

一体化多效澄清系统在水厂排泥水处理中的应用

老旧水厂新建排泥水设施大多面临用地紧张问题。针对南方某水厂排泥水浑浊度大、混凝程度高、分离性好的水质特点,以及污泥含水率低于80%、上清液SS质量浓度不高于50 mg/L的处理目标,某水厂采用了集成化设备处理工艺“一体化多效澄清系统+带式浓缩脱水”。该系统针对排泥水特点优化了混凝反应区和沉淀区以提高运行效率,项目运行稳定可靠,污泥含水率低于65%,上清液SS质量浓度低于15 mg/L,在同类型项目中具有投资低、占地小、处理效果好的优势。

“絮凝脱水+高压带机+好氧发酵”组合工艺在粪便污泥处理中的应用

河北省某粪便处理站收集并处理附近学校产生的粪便污水,原采用“絮凝脱水+好氧发酵”工艺,将粪便污泥处理至含水率84%左右,然后进行好氧发酵堆肥。但是,含水率84%的粪便直接进行好氧发酵,必须添加大量辅料,存在堆肥物料易板结、氧气传质效率低、运行成本高等问题,影响堆肥产品质量。为提高粪便污泥好氧发酵效率,降低运行成本,在充分利用原有设备和场地的前提下,原脱水工艺后端和好氧发酵工艺前端增加高压带式深度脱水工艺。该项目连续运行结果表明,经高压带式深度脱水工艺处理后,粪便平均含水率从84%降至59%,粪便减量率达61%,节省辅料90%,改造后粪便减量效果和经济效益显著。

废水污泥用功能复合型脱水剂制备及应用研究

针对复杂废水污泥高效脱水,开发应用复合型絮凝脱水剂尤为重要。以天然钠基膨润土、2-丙烯酰胺-2-甲基丙磺酸、对苯乙烯磺酸钠、交联复合乳液为主要原料,调节不同配比,辅以引发剂,采用共聚反应方式制备功能复合型絮凝脱水剂AW。通过污泥脱水去除率及脱水速率提升效果确定最佳质量比,可发挥各组分结构的独特作用,实现高效污泥脱水。结果表明:该絮凝脱水剂较常规絮凝脱水剂综合脱水率提高5%~10%,脱水速率提高3倍以上,性能优异。

一步法污泥超深度压滤脱水工艺研究

污泥常规脱水后含水率可到80%~85%,需深度脱水以满足后续处理需求。本研究采用高压板框压滤机,探索含水率80%污泥的直接深度脱水。结果表明,投加聚硅硫酸铁可将含水率降至60%以下,投加三氯化铁和石灰乳则更低。此工艺处理效率提升40%,且投资与运行成本均低于常规工艺,经济效益显著,为污泥深度利用提供了高效、经济的新途径。

低温干化技术在市政污泥处理中的应用

在市政污泥处理过程中如果忽略了热平衡问题,处理后的污泥含水率将较高。为了给污泥处理提供更多选择,开展低温干化技术在市政污泥处理中的应用研究。以污泥质量分数、热流为指标,绘制市政污泥的热重曲线,分析低温干燥特性。根据能量守恒定律,计算低温干化处理热平衡,确保足够的热量传递给污泥以促进水分的蒸发和迁移。与低温真空脱水干化成套设备相结合,对低温真空干燥机理进行研究,通过脱水干化,改善污泥含水率,满足污泥减量化要求。由应用案例分析结果可知,所研究技术对于含水率85%、70%、68%、65%、60%的污泥,通过低温干化下降到10%、10%、10%、9%、8%,满足干化后理想含水率不大于10%的要求。

Experimental continuous sludge microwave system to enhance dehydration ability and hydrogen production from anaerobic digestion of sludge

Dehydrating large amounts of sludge produced by sewage treatment plants is difficult.Microwave pretreatment can effectively and significantly improve the dewaterability and hydrogen production of sludge subjected to anaerobic digestion. The aim of this study was to investigate the effects of different microwave conditions on hydrogen production from anaerobic digestion and dewaterability of sludge. Based on an analysis of the electric field distribution, a spiral reactor was designed and a continuous microwave system was built to conduct intermittent and continuous experiments under different conditions. Settling Volume, Capillary Suction Time, particle size, and moisture content of the sludge were measured. The results show that sludge pretreatment in continuous experiments has equally remarkable dehydration performance as in intermittent experiments; the minimum moisture content was 77.29% in the intermittent experiment under a microwave power of 300 W and an exposure time of 60 sec, and that in the continuous experiment was 77.56% under a microwave power of 400 W and an exposure time of 60 sec.The peak measured by Differential Scanning Calorimeter appeared earliest under a microwave power of 600 W and an exposure time of 180 sec. The heat flux at the peak was 4.343 W/g, which is relatively small. This indicates that microwave pretreatment induced desirable effects. The maximum yield of hydrogen production was 7.967% under the conditions of microwave power of 500 W, exposure time of 120 sec, and water bath at 55℃. This research provides a theoretical and experimental basis for the development of a continuous microwave sludge-conditioning system.

PAM与PAC复配调理对污泥脱水及流变的影响

探究有机调理剂(PAM)与无机调理剂(PAC)联用对北京市某污水处理厂热水解厌氧消化污泥脱水及流变的影响。结果表明,单独投加PAM或PAC均可以提高抽滤泥饼含固率,PAM效果要优于PAC。当复配投加PAC掺量4%,PAM掺量2.5‰时,滤饼的含固率最高,达到35.15%。经PAC+PAM联合调理的污泥,相比原泥和单一调理剂的污泥,有着更少的S-EPS和LB-EPS,表明污泥脱水能力有显著提升。添加复配调理剂的污泥中蛋白含量最少,结合水得到释放,有利于水分去除。此外,PAM的投加能降低污泥的屈服应力,而PAC则会增大调理污泥的屈服应力,PAM、PAC能增大污泥稠度,降低流动行为指数(n)。复配调理污泥表现出与PAM单独调理污泥相似的流变参数变化规律。

污泥预调理方式影响下市政污泥“深度脱水-干化-焚烧”碳排放

基于污泥深度脱水中试示范,根据联合国政府间气候变化专门委员会(IPCC)提供的方法,对比新型污泥生物裂解绿色预调理技术和常规化学药剂(铁盐+石灰)预调理方式下的污泥“深度脱水-干化-焚烧”处理处置工艺碳排放特性.结果表明,污泥经过两种方法预调理后,板框压滤污泥含水率均能降至60%以下,但压滤泥饼干质含量和干基热值差异明显.经生物裂解后的污泥干质含量比投加铁盐+石灰的污泥减少23.0%;同时,其污泥干基热值较投加化学预调理后的高32.1%.通过碳排放量计算,处理每立方米含水率为98%的污泥,基于生物裂解的污泥“深度脱水-干化-焚烧”处理处置工艺总碳排放为15.8kg CO_(2)eq/m^(3)RS,比基于化学预调理工艺的总碳排放量(27.1kg CO_(2)eq/m^(3)RS)低41.7%.

超声时间对污泥脱水性能的影响

污泥絮体紧紧包裹大量结合水,导致污泥脱水性能很差。超声波处理是改善污泥脱水性能的有效处理方法之一。针对超声时间对污泥脱水性能的影响进行了一系列研究。超声波作用在液相中产生瞬时高温高压,其声空化和水力剪切作用通过裂解污泥絮体,将难以去除的结合水释放出来,改善污泥脱水性能。同时,也释放了胞内大量的有机酸或碳酸类物质,改变了污泥的pH值。但是,超声波作用存在最优作用时间,无限延长超声波作用时间,污泥絮体和微生物细胞将变得更加破碎,污泥脱水性能会恶化。

活化过一硫酸盐强化调理污泥脱水研究

为强化过硫酸盐氧化技术改善污泥调理的效果,提高污泥的脱水性能,采用Fe(Ⅱ)活化过一硫酸盐(PMS)对市政污泥进行调理。在单因素试验的基础上,利用Box-Behnken设计的响应曲面法,以毛细吸水时间(CST)降低率为响应值,对PMS搅拌转速、PMS搅拌时间、FeSO_(4)搅拌转速、FeSO_(4)搅拌时间4个影响因素进行优化,结果表明,在PMS搅拌转速为100r/min,PMS搅拌时间为19min,FeSO_(4)搅拌转速为230r/min,FeSO_(4)搅拌时间为60min的条件下,CST降低率可达到59.94%,表明过硫酸盐体系的搅拌优化对于污泥调理环节有着强化作用。

絮凝剂投配率对市政混合污泥离心脱水性能的影响研究

为了优化再生水厂中污泥脱水的处理效果,开展了污泥脱水小试和生产性试验。通过调整离心机不同的絮凝剂投配率,观察污泥絮体形态、上清液情况、污泥毛细吸水时间等的变化趋势,对污泥脱水效果进行研究。结果表明,当絮凝剂投配率为0.36%~0.43%时,污泥沉降性能较好,离心机液压站压力与出泥含水率有高度负相关性,可以用液压站压力数值来指示离心机出泥含水率水平;从综合效果与经济性考虑,投配率为0.45%~0.56%时,可以在保证处理效果的同时,还能够留出适当的投配率余量来应对进泥含水率的变化,是综合性较好的投配率范围。

餐厨垃圾堆肥产物用于综合利用工程废弃料的试验研究

为积极响应国家循环经济发展与解决西部大开发过程中产生的大量工程废弃料处置问题,用有机质含量丰富的固体废弃物餐厨垃圾堆肥产物去综合利用渗透稳定性极差、有机质缺乏的工程废弃料粗砂土、砂石骨料脱水污泥,试验了3种材料不同质量比的混配方式,并以纯的粗砂土为对照。结果表明,在粗砂土∶砂石骨料脱水污泥∶堆肥产物=5∶3∶2(质量比)时,土壤容重、pH、有机质均满足《园林绿化种植土壤技术要求》(DB11/T 864—2020)的一般绿化要求,电导率也基本达到一般绿化要求,而种植黑麦草后的发芽势、发芽率、株高、茎粗、地上生物量以及土壤总孔隙度相对纯的粗砂土都显著提高,并且容重最低,发芽率最高,60 d的株高最高,茎粗最粗,地上生物量最大。因此,餐厨垃圾堆肥产物可以用来综合利用工程废弃料砂石骨料脱水污泥和粗砂土而制备园林用土。

污泥无害化处理及其在烧结砖中的应用

介绍了一种污泥低温干化+碳化+建筑材料利用技术,通过该技术,将80%高含水率污泥经过低温干化脱水、高温余热碳化处理,制成具有一定热值的碳化污泥,并掺入制砖原料中生产烧结砖,真正实现了污泥减量化、稳定化、无害化及资源化利用。