【作者】 林楚娟；

【导师】 孙水裕；

【作者基本信息】 广东工业大学 ， 环境工程， 2008， 硕士

【摘要】 利用超声波破解城市污水厂的剩余污泥,可以改变污泥特性,并使污泥胞内外物质溶出进入水相,不但有利于溶出物作为微生物的底质实现隐性生长,促进后续污泥消化速率,减少污泥固体量,而且会影响污泥的脱水性能。本文利用低频(28kHz)槽式超声波清洗反应器,破解广州市某城市污水厂的剩余污泥,研究超声波破解污泥沥出液的溶出机制,并探索将剩余污泥破解后通过缺氧/好氧消化工艺进行隐性生长对污泥稳定化和减量化的促进作用。试验结果表明,超声波对污泥起到显著的溶胞作用,污泥经超声破解后,沥出液中SCOD、TN、TP在短时间内等基本上呈线性增加趋势,提高了污泥的可降解性能。从超声波促进污泥胞内外物质进入液相来看,在相对较低的声能密度范围内,采用0.05w/mL的声能密度较为理想,从超声波在一定辐照时间内污泥状态及生物相来看,辐照20min不但可以起到较好的溶胞作用,而且可以避免产生丝状菌膨胀,因此,采用0.05w/mL的声能密度辐照20min将在经济性及破解效果方面取得较佳的平衡。为了验证超声波的作用对污泥消化效果的影响,进行了三组污泥的US(超声波)—A/AD(缺氧/好氧消化)工艺20天消化的对照试验,结果表明,在相同的室内温度、相同的初始污泥条件、相同的缺氧/好氧消化条件下,每天对其中13.3%的污泥输入一次频率为28kHz、声能密度为0.05w/mL、辐照时间为20min的2#池子污泥的消化稳定化效果最好,经过16天的消化后,其VSS去除率达到45.2%,20天的消化后去除率达到50.35%;而每天输入两次相当于2#池子一次能量输入的3#池子次之,其16天后的VSS去除率为38.69%,20天后的VSS去除率为44.44%:对比组1#池子最低,16天消化的VSS去除率为38.4%,20天消化的VSS去除率为40.53%。为了进一步考察在低剂量超声波作用下US—A/AD工艺的消化效果,通过在较佳的工艺条件下进行US—A/AD污泥消化工艺的扩大试验,每三天辐照(常温下,频率28kHz,声能密度0.05w/mL,20min)5%的污泥量,经过16天的消化,污泥中VSS的平均去除率达到40.95%,已经能够满足《城镇污水处理厂污染物排放标准》(GB18918-2002)中污泥稳定化的要求。污泥经过20天的消化之后,TSS和VSS的平均去除率分别为30.4%和47.53%。通过对US—A/AD污泥消化系统一个消化周期的考察,超声波的作用使得污泥中有机物迅速溶出,使得污泥的迅速减量成为可能;而对污泥中有机物的去除减量作用主要发生在好氧段,在好氧微生物的作用下,有机物不断被作为底物利用消化,使污泥中的VSS不断减少,从而实现了污泥的稳定化和减量化;而缺氧段则为污泥提供了脱氮作用及稳定系统pH值,保持系统稳定运行的作用,缺氧段的反硝化作用,使污泥上清液中的TN不至于不断累积。更多还原

【Abstract】 Use of ultrasound disintegration the waste activated sludge (WAS) of urban sewage plant, can change the characteristics of sludge, and the substances inside and outside of the sludge cells dissolution into the liquid phase, is conductive not only the dissolution of micro-organisms as of the end of the realization of hidden growth, promote follow-up sludge digestion rate, reduce the amount of solid sludge, but will affect the dewaterability of sludge. In this paper, the low-frequency (28 kHz) trough ultrasonic cleaning reactor is applied to disintegrate the WAS from Guangzhou Lijiao urban sewage plant. The solution mechanism of released liquid from ultrasonic WAS disintegration is studied, and the promotion action of ultrasonic disintegration to sludge stabilization and reduction in WAS anoxic/aerobic digestion technology of hidden growth is researched.The results showed that the ultrasound played signigicant role in the sludge cell lysis, the SCOD, TN, TP of supernatant after a short period of time of ultrasonic radiation is basically a linear trend of increase, and the sludge biodegradable properties is improved. Ultrasonic promote sludge from the cellular material into the liquid inside and outside, in the relatively low density of the sound energy, a 0.05 w/mL of sound energy density is more ideal. Seeing from the state of particles and biota in the sludge in a certain time of ultrasonic radiation, 20 minutes of irradiation not only can play a better role in the dissolution cell, but avoid a filamentous expansion. Therefore, a 0.05 w/mL of sound energy density and 20 minutes radiation in the economy and disintegration results achieved strike a better balance.In order to verify the role of ultrasound on the effects of sludge digestion, the three controlled groups of sludge ultrasonic-anoxic/aerobic digestion (US-A/AD) process was designed to digest for 20 days. The results showed that in the same room temperature, the same as the initial conditions of sludge, the same anoxic/aerobic digestion conditions, sludge digestion stability of No. 2 digestive tank(a frequency of 28 kHz, 0.05 w/mL of sound energy density, 20 minutes of irradiation time and 13.3 % of the sludge) was the best. After 16 days of digestion, its volatile suspend solid (VSS) removal rate reached 45.2 percent, after 20 days of digestion, the VSS removal rate reached 50.35 percent. No.3 digestive tank was followed by No.2. It was entered twice daily equivalent energy of No.2 digestive tank. After 16 days of digestion the removal rate of the VSS was 38.69 percent. After 20 days the removal rate of the VSS was 44.44 percent. The comparison group No.1 tank was the minimum. After 16 days of digestion the VSS removal rate was 38.4%, 20 days the VSS removal rate was 40.53 percent.To further study the digestive effects of low-dose ultrasound under US-A/AD digestion process, through better technical conditions under extension test of the US-A/AD sludge digestion process , every three days irradiation (at room temperature, Frequency of 28 kHz, 0.05 w/mL of sound energy density, 20minutes) 5% of the sludge, after 16 days of digestion, the average removal rate of VSS in the sludge reached 40.95 percent, has been able to meet the request on the sludge stabilization of "Urban Sewage Treatment Plant Emissions Standards "(GB18918-2002) . After 20 days of sludge digestion, the average removal rate of TSS and VSS, were respectively 30.4 percent and 47.53 percent. In an inspection of a cycle (24hours) digestive period in the US-A/AD process, ultrasonic sludge makes the role of organic matter in the rapid dissolution, which makes sludge quickly reduction possible. And the removal and reduction of organic compounds in the sludge mainly happened in the aerobic period. Through aerobic microbes, organic matter has continually been used as a substrate to digest, so that VSS in the sludge decline, thus achieving the stability and minimization of the sludge. And anoxic digestion of the sludge is to provide the system stable nitrogen and pH value, and maintain the system stable operation. The denitrification in the anoxic period, makes the TN in the supernatant of the sludge system inaccumulate.更多还原