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粪尿废水的单独厌氧处理试验研究

Experimental Study on Anaerobic Treatment of Manure Wastewater

【作者】 赵丙良

【导师】 袁林江;

【作者基本信息】 西安建筑科技大学 , 环境工程, 2011, 硕士

【摘要】 随着经济的快速发展,我国污水排放量急剧增加,水污染问题开始影响人们的生活与健康。尽管近些年政府已加大了污水处理的投资量,在污水治理方面有了长足的发展,但传统集中式污水处理系统表现出很大的弊端,相比之下,分散式污水处理的优势则不断的显现出来。分散式污水处理系统的核心是源分离(Source Separation)或源管理(Source Management),即将人粪尿污水与生活杂排水分开处理并进行能量和资源的回收,而将受污染程度低的杂排水和雨水分散资源化。由于粪尿废水含有大量有机物、氮磷以及病原菌,因此成为分散式型污水处理研究的一大热点。尽管其处理方法从最早的粪便堆肥到后来的厌氧化粪池(Septic Tank),再到后来,国外开发出了应用广泛的上流式厌氧污泥床化粪池(UASB septic tank),但纵观国内外多年来关于粪尿废水处理的研究和实践,粪尿废水的处理还存在一些问题,反应器的性能和处理效率有待进一步提高,屎尿废水中可能含有大量病原微生物,而厌氧处理对废水的病原菌的去除规律并不清楚,有待研究。为了提高粪尿废水厌氧处理反应器的性能和净化效率(COD和病原微生物),本课题在外循环UASB反应器中改进了反应器内部搅拌方式,增强了混合程度,考察了了中温(35℃)条件下反应器处理粪尿废水的性能。试验结果表明:1.粪尿废水的pH、COD、SS、氨氮等指标均存在较大的波动。其中pH值在7.30~8.6之间,呈现弱碱性,这对厌氧反应器的正常运行很不利,需要人工调节进水pH。原水中悬浮态的CODss含量约占总进水COD的45%,较高的悬浮物会影响厌氧反应器的稳定运行。但通过调节回流量可以提高反应器抗冲击负荷的能力。2.在反应器启动初期,厌氧污泥尚未驯化,开启回流会扰动污泥,产生上浮,不利于反应器稳定。当反应器开始稳定产气时,污泥床又会因上升流速过小而产生短流或活塞式推流,导致浮泥现象,不利于反应器的稳定运行。此时开启混合液回流装置,提高上升流速,则浮泥现象消失,去除效率上升。3.采用厌氧絮体污泥接种,通过回流装置不断增大上升流速,污泥的颗粒化进程明显加快,并最终实现污泥颗粒化。4.厌氧反应器内形成的颗粒污泥形状较规则,颜色呈黑色和灰黑色;表面较光滑致密,大量丝状菌网状缠绕,短杆菌和少量球菌镶嵌其中;颗粒污泥内部结构密实,含有大量丝状菌,球菌和少量短杆菌;污泥粒径主要分布在0.6~0.9mm。5.当污泥颗粒化后,反应器内的SLR为0.15~0.36kgCOD/(kgVSS·d),上升流速为1.16~1.27m/h时,反应器对COD的去除效率更好,去除率在72%左右。研究同时发现,在此上升流速下增大污泥负荷对反应器的产气率并没有显著提高,每去除1gCOD的产甲烷量平均为183mL。6.以粪大肠杆菌为指示,反应器主要依靠污泥的粘附作用去除病原菌,且絮状污泥对原水中游离态病原菌的去除效果比颗粒污泥好,而对悬浮态病原菌则无显著差异;污泥颗粒化后,HRT与粪大肠杆菌去除率呈正相关性。外循环UASB反应器处理黑水时,有机物的快速高效去除同病原菌的去除并不同步。

【Abstract】 With rapid development of economy and serious lack of resources, traditional centralized wastewater treatment system shows more and more drawbacks. By contrast, decentralized system has many advantages. In decentralized wastewater treatment system,key piont is Source Seperation or Source Management. In decentralized system faecal wastewater is separated from ordinary domestic wastewater. Black water treatment is the hotpot in decentralized system, and the methods are manure compositing, septic tank and UASB septic tank, which is most widely used abroad. The research about black water treatment at home and abroad mainly pay close attaintion to improving the reactor and efficiency by stirring, wastewater’s well distributing, designing good three phase seperater and so on.This test investigated the treatment of blackwater from classroom building by using an Externally Circular UASB reactor, and the system was operated at 35℃. During the experiment, several index were monitored to check the performance of this system such as pH value, COD, SS, NH4 N, TN,VFA, with the quantity of influent and mixed liquid returning changing. The results indicated that:1. Several index of the raw wastewater such as pH, COD, SS and ammonia nitrogen fluctuated widely. pH value of wastewater was between 7.30 to 8.6, and showed a weak alkaline. This is not conducive to the operation of the reactor, and need to manually adjust the influent pH value. The CODss content of raw water is about 45% of total COD, and this has great effects on high rate anaerobic reactors. But the reactor’s ability to loading shock has been strengthened by changing the quantity of reflux.2. During the starting up of reactor, the anaerobic sludge has not been domesticated. if starting reflow, it would disturb the sludge and floatation. That was not good for the stabilization of reactor. When the reactor had stably producted gas, the sludge bed would have short flow or plug flow because of low Vup(velocity of up flow), which resulting in mud flotation. This was bad for the reactor’s stabilization. At this time, opening the back flow devices to improve Vup has made removal efficiency increased.3. Inoculating with anaerobic sludge flocs in the UASB reactor, floc sludge granulation has increased by improving upflow velocity through the back flow devices, and, floc sludge has achieved granulation at last.4. Anaerobic reactor formed regular shape of granular sludge, which was black and gray black and dense smooth surface. A large number of filamentous bacteria was wrapping a few cocci and Brevibacterium. The internal of granular sludge is containing a large number of filamentous bacteria, cocci and a small amount of Brevibacterium. Sludge particle size was distributed in the 0.6 0.9mm.5. After the granulation of sludge,the SLR and Vup were 0.15~0.36kgCOD/(kgVSS·d)and 1.16~1.27 m/h respectively, the removal efficiency of COD was better. At the same time, increasing sludge loading of reactor has little effect on gasification efficiency. The average output of CH4 was 183mL when 1gCOD has been removed.6. With fecal coliform as indicator, the reactor mainly depended on the adhesion of sludge to remove pathogens, and the removal efficiency of Pre columri prior pathogen was better than removed by the granular saudge. While the suspended bacteria showed no significant difference. After granulation, HRT and fecal coliform removal was positively correlated. The results indicated that treatment with UASB Blackwater outside the circle, fast and efficient removal of organic matter with the efficient removal of pathogens could not coexist

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