热碱预处理论文：热碱预处理对剩余污泥的溶胞率及发酵产酸的影响研究.docVIP

热碱预处理论文：热碱预处理对剩余污泥的溶胞率及发酵产酸的影响研究 【中文摘要】随着国民经济的快速发展,污水处理技术的不断提高,剩余污泥总量迅速增加。如何快速、有效、环保的处理剩余污泥,是一个迫在眉睫的问题。传统的厌可以实现污泥的稳定化、减量化、产生清洁能源沼气,但是,水解时间较长。目前,有化学、物理、生物等加速污泥水解的方法,其中热碱预处理方法,不仅在细胞破解方面卓有成效,而且可以加强污泥的后续处理效果。多数厌氧发酵研究以甲烷为最终目标产物,很少探讨剩余污泥发酵的中间代谢产物挥发性短链脂肪酸。它作为高附加值的生物化学品,不仅是转化成甲烷的主要物质,还可以作为其他化学物质如醋酸乙烯等的原料。本论文应用响应曲面法优化热碱预处理剩余污泥工艺条件,获得最佳试验参数。在最佳试验条件下处理剩余污泥,进行中温厌氧发酵试验,探讨热碱预处理对剩余污泥发酵产酸的影响。利用响应曲面法对热碱预处理剩余污泥工艺进行条件优化,实验因素分别为:温度(℃)、pH值和时间(min);响应值为剩余污泥溶胞率(%)。在单因素实验的基础上选取实验因素水平,根据Box-Benhnken实验设计原理采用三因素三水平的响应曲面法,建立了热碱预处理对剩余污泥溶胞率影响的二次多项数学模型,并通过以剩余污泥的溶胞率为响应值作为响应面图和等高线图,并分析各个因素间的显著性和交互作用。结果表明,低温热碱预处理剩余污泥三个自变量因素温度、pH和反应时间对剩余污泥溶胞率的影响从大到小依次为:pH,温度,反应时间;溶胞率最佳的操作条件为:温度为89 1℃,pH值为12.00,时间为74 1min。在最佳工艺条件下,细胞的溶出率为48.05%。基于响应曲面法对热碱预处理剩余污泥工艺条件的优化结果,处理剩余污泥,对热碱预处理后的剩余污泥中温厌氧发酵产酸情况进行探讨。试验结果表明,厌氧发酵期间,热碱预处理剩余污泥中溶胞率、溶解性蛋白质、溶解性总糖、乙酸、异丁酸、正丁酸、异戊酸、正戊酸的积累量均高于未处理剩余污泥其中,乙酸积累量高于未处理组约8 10~3mgCOD/L,总酸积累量高于未处理组约210~3mgCOD/L;热碱预处理方法可以改变挥发性短链脂肪酸在厌氧发酵期间的特征分布,但乙酸含量在两组中都占有绝对优势;未处理剩余污泥厌氧产酸总量、乙酸含量在第8 d、第5 d达到最大值,热碱预处理剩余污泥是第3 d、4 d,较前者分别提前5 d、1 d; 【英文摘要】With the development of economy and waste activated sludge treatment technology, the amount of waste activated sludge increased very rapidly. The development of effective and environmental friendly disposal techonology of excess sludge had become one of the most complex problems. It was known that anaerobic fermentation can make waste activated stabilized and reduction and produces the methane. However, it took a long time to derupt the cell wall. Recently, to accelerate the hydrolysis of sludge, various sludge pretreatment technologies have been developed, such as chemical, physical, biological and other methods. As an effective method, the thermal朼lkaline pretreatment of sludge can not only fruitful to break the cell, but also strengthen the follow-up of sludge treatment results. With respect of anaerobic fermentation, most of these studies in the literature were conducted for direct methane generation,it has few studies aiming at the production of volatile fatty aci