亚硝化颗粒污泥对温度变化的响应特性研究

采用序批式反应器(SBR),以实验室已经培养好的具有良好亚硝化积累的颗粒污泥(短程硝化积累率90%以上)为接种污泥,考察了温度变化对亚硝化颗粒污泥特性、稳定性、氮转换性能及活性的影响.结果表明,温度对亚硝化颗粒污泥的结构和短程硝化性能都有着重要的影响.在30℃时,亚硝化颗粒污泥具有良好的絮凝和沉降性,污泥结构紧密,亚硝化积累率维持在96.17%,污泥容积指数(SVI)为39 mL.g-1,平均粒径为3.03 mm.当温度降至25℃时,由于胞外多聚物(EPS)浓度升高,蛋白质与多糖比值的下降,导致亚硝化颗粒污泥的电负性升高,同时污泥表面的疏水性减弱,结构变得松散,亚硝化颗粒污泥发生了解体,亚硝化积累率在35%以下,短程硝化被破坏.在15℃时,虽然亚硝化颗粒污泥也发生了解体,并且解体现象加剧,但是由于颗粒污泥表面氧气传质深度的增大,使得反应器中氨氧化菌(AOB)的数量相对增大,出水亚硝化积累率最终稳定在68%左右.

Effect of Temperature on the Response Characteristics of Shortcut Nitrification Granular Sludge

The experiment was carried out in a sequencing batch reactor (SBR), using granular sludge with 90% shortcut nitrification accumulation ratio, which had been cultivated by the laboratory to seed the reactor. The effects of temperature on characteristics, stability, nitrogen conversion properties and activity of short-cut nitrification granular sludge were investigated. The results show that the temperature has a significant influence on structure and short-cut nitrification performance of short-cut nitrification granular sludge. 30 degrees C was the optimum temperature for shortcut nitrification granular sludge cultivation, and the granules were more compact which led better flocculation and settleability. SVI and average diameter of sludge reached up to 39 mL x g(-1) and 3.03 mm, respectively. The nitrification accumulation was maintained at 96.17% during this period. When the temperature was at 25 degrees C, the granules changed to a loose-structure along with the electronegativity increased as well as the hydrophobicity decreased, which was due to the increase of EPS and decreased ratio of protein to polysaccharide. The granules disintegrated during this period, at the same time, the nitrification accumulation ratio was below 35%. It can be seen that the shortcut nitrification performance was destroyed. At 15 degrees C, the shortcut nitrification sludge also disintegrated and had a looser structure. However, the oxygen penetration depth increased at a lower temperature, which made the relative quantity of ammonia oxidizing bacteria (AOB) in reactor increased, the nitrification accumulation was around 68% ultimately.