【作者】 张少强；

【导师】 李小明；

【作者基本信息】 湖南大学 ， 环境工程， 2007， 硕士

【摘要】 活性污泥法是目前应用最广泛的污水生物处理工艺,但会产生大量剩余污泥。目前,剩余污泥的处理与处置已成为污水处理厂一个令人头痛的问题,其费用占到污水处理厂总运行费用的25%～40%,甚至高达60%。因其费用高昂及其污泥最终处置对环境污染潜在的危害等问题,一直制约着污水处理厂的建设和发展。污泥减量化技术正是在这一背景下应运而生的。所谓污泥减量化,是指在保证污水处理效果的前提下,采用适当的措施使处理相同量的污水产生的污泥量降低的各种技术。本文综合介绍了国内外有报道的三种常见的污泥减量化技术:降低细菌合成量的解偶联技术、增强微生物利用二次基质进行隐性生长的各种溶胞技术、利用食物链作用强化微型动物对细菌捕食的技术。并针对基于隐性生长的生物溶胞作用的污泥减量化作了深入探讨。本研究中嗜热菌污泥减量化技术分为两个部分,包括污泥在嗜热菌作用下的好氧消化与污泥传统高温好氧消化的对比研究;另外,进行了嗜热菌污泥减量化影响因素分析,分别考察温度、污泥初始浓度、溶解氧、嗜热菌接种量等因素对嗜热消化过程的影响。研究表明污泥在嗜热菌作用下的好氧消化效果和消化效率均优于传统高温好氧消化,具体表现在TSS、VSS去除率以及消化周期上,嗜热好氧消化TSS、VSS去除率分别达到55%和65%,高出传统高温好氧消化的40%和50%,另外其消化周期约为72 h,而传统好氧消化为96 h,缩短了近1/4。通过对消化过程中TCOD、SCOD、NH4+-N等指标的测定,污泥在嗜热菌作用下的好氧消化过程以上指标变化过程均明显优于传统的好氧消化。研究表明温度是嗜热菌污泥减量化的重要影响因素之一。随着温度的升高,污泥嗜热菌好氧消化周期逐渐缩短、污泥消化的效果逐渐提高。但也并不是温度越高越好,针对本研究中的嗜热菌而言,在65℃条件下活性最大,对污泥的降解也比较彻底,TSS、VSS降解和去除率上,最高可达到55%和65%。污泥的初始浓度也影响着嗜热菌污泥减量化效果,污泥初始浓度越高,消化过程中VSS的去除率会越低;而对VSS去除量而言,污泥的初始浓度越高,污泥嗜热好氧消化过程中VSS的去除量就会越高。溶解氧浓度对嗜热菌污泥减量化的影响也比较明显,溶解氧DO的浓度大小影响着VSS去除率,当DO≥2 mg/L时,污泥消化系统中的DO浓度增加时,污泥消化过程中VSS的去除率并无明显增加。当DO浓度达到一定值时,再增加DO浓度的情况下, VSS去除率不仅不会增加,反而开始变得下降,最佳溶解氧浓度应控制在2 mg/L左右。嗜热菌菌种接种量大小对嗜热菌污泥减量化过程中的VSS去除率也有一定影响,但并不是主要影响因素,当接种量为>1%时,反应系统中的嗜热菌接种量增大,污泥消化过程中VSS的去除率有增加,但增效不明显。当嗜热菌接种量达到一定比例时,再增加嗜热菌接种量的情况下,污泥的嗜热菌消化效果没有什么变化,接种量应控制在5%为宜。更多还原

【Abstract】 Now the actived sludge process has been used more and more extensively, but a large quantity of excess sludge was produced. The problems of treatment and disposition to the excess sludge become difficult and troublesome, the cost can account for 25% to 40%, up to 60% of total plant operation costs. The final sludge disposal became more and more difficult with potential pollution to the environment as well as the limitation of the land area available for the disposal. The sludge reduction technologies are studied in lately decades.The sludge reduction are some technologies which can reduce the quantity of sludge priduction, ensuring the same sewage quantity and treatment quality with having been taken some measures.The possible approaches for sludge reduction may be based on three aspects: uncoupling metabolism, cryptic growth enhanced through cell lysis and microfauna pry. Relevant research works were reviewed, characteristics of each technology were compared, and the sludge reduction based on cryptic growth was discussed particularly.The sludge reduction technology with thermophilic bacteria was divided into two parts, including sludge digestion by the aerobic Thermophilic bacteria was compared with the conventional aerobic sludge digestion at 60, 65, 70℃, and the influences of temperature, the initial concentration values of sludge, dissolved oxygen and the inoculation quantity of thermophilic bacteria were each studied in this paper.The research results indicated that the digestion effect and efficiency of sludge by the aerobic thermophilic bacteria were much better than the conventional aerobic sludge digestion at each three temperature as said before. The removal rate of TSS and VSS was just 40% and 50% for the conventional aerobic sludge digestion process, but in the thermophilic bacteria sludge digestion, The removal rate of TSS and VSS respectively reached 55% and 65%, corresponding to the before both higher fifteen percents. In addition, the digestion cycle was declined from 96 hours to 72 hours, and was shortened by 1/4 than the simple aerobic digestion. The changes about the parameter of TCOD、SCOD、NH4+-N et al. in the thermophilic bacteria sludge digestion were more clearly and better than the conventional process.Temperature was an important effect factor to the thermophilic bacteria sludge digestion. The cycle of sludge digestion was shortened, and the efficiency of sludge digestion was enhanced. But, it was oppositely, not endless. When temperature reached 70℃, its tend of improvement became so unconspicuous. The best temperature for the excess sludge digestion with thermophilic bacteria appeared at 65℃, when the biodegradation for sludge was more completely, The removal rate of TSS and VSS were higher.The thermophilic bacteria sludge digestion with the different initial concentration values of sludge was studied. When the initial concentration values of sludge was very low, higher removal rate of TSS and VSS has been achieved; when the initial concentration value was very high, the removal rate of TSS and VSS was also very low, the aim to remove much VSS from the excess sludge through digestion method with the thermophilic bacteria will be not obtained. Further more, the phenomenon that removal quantity of TSS and VSS was increased along with the increasing initial concentration value of sludge was indicated in the research results.Dissolved oxygen was one more important effect factor to the thermophilic bacteria sludge digestion. When the dissolved oxygen concentration was around 2mg/L, the thermophilic bacteria could be enriched and the removal rate of TSS and VSS was increasing along with the DO. The DO reached one value while the removal rate of TSS and VSS became steady gradually, no increasing. With the increasing DO, the removal had even declined. The best DO concentration value for the excess sludge digestion with thermophilic bacteria appeared at around 2 mg/L.The inoculation quantity of thermophilic bacteria was one effect factor to the thermophilic bacteria sludge digestion. But the research results indicated that its influence was not so important and obvious. There were no different changes in the removal rate of TSS and VSS if the inoculation quantity changed, and the best inoculation quantity to the thermophilic bacteria or sludge of this study was 5% (volume ratio).更多还原