UASB处理高浓度硫酸盐废水启动过程污泥特性变化

跟踪比较一套处理高浓度硫酸盐污水的UASB反应器从启动驯化到稳定运行的243 d内污泥特性的变化.结果显示颗粒污泥的形成与生物活性直接影响反应器的处理效率.反应器启动初期颗粒污泥的平均粒径由种泥的1.82 mm减少至0.99 mm;随着负荷增加、水力停留时间缩短,颗粒污泥平均粒径呈逐步增长趋势.采用N2吹脱反应器内产生的H_2S,N_2流量为60 mL·min~(-1)时,颗粒污泥的平均粒径快速增长至1.51 mm;N_2流量为100 mL·min~(-1)时,颗粒污泥平均粒径呈现下降趋势;N_2连续吹脱使得反应器内不同高度污泥的平均粒径趋于接近.污泥中活性微生物的量(MLVSS)在启动初期先降后升,升至33.59 g·L~(-1)之后平稳增长到49.72 g·L~(-1),活性污泥中微生物所占悬浮固体量的比例(MLVSS/MLSS)也呈相同的变化趋势,先下降后升至0.36之后平稳升至0. 50;相关性分析表明,反应器硫酸盐还原效率与MLVSS呈显著正相关(r=0.918,p=0.003),驯化过程中SO_4~(2-)还原效率为30%～95%.电镜分析表明,接种时颗粒污泥表面粗糙,结构松散,多为丝状菌、杆菌、球菌;驯化后颗粒污泥表面光滑内部微生物结构紧密,菌群密集,多为弧菌、杆菌.硫酸盐还原反应器驯化过程中负荷、水力停留时间、反应器内水力上升流速、以及N2吹脱强度和时间都影响颗粒污泥粒径的变化;污泥中菌群组成的变化也可能是影响颗粒污泥粒径变化因素之一.

Changes of Sludge Characteristic in Start-up Process of UASB Treatment for Highly Sulfate-containing Wastewater

Changes of sludge characters in a sulfate-reducing UASB reactor during the 243 day of domestication process were tracking comparison.Results showed the average diameter of granular sludge in initial domestication stages decreased to 0.99 mm compared with 1.82 mm of incubating sludge, but which was found to be increasing along with the enhance of the loading rate of reactor, the shorten of HRT, and the acceleration of hydraulic up-flow velocity.N_2 stripping was used to remove H_2S produced in the reactor, and the average diameter of granular sludge increased to 1.51 mm quickly when N_2stripping with the flux of 60 mL·min~(-1) was used, but it decreased when the flux of N_2 improved to 100 mL·min~(-1). Differences in average diameter among granular sludges in different height of the reactor became unconspicuous through continuous stripping. Changes in the MLVSS and the ratio of (MLVSS/MLSS) displayed similar trends, for which firstly decreased in the earlier period then increased to 33.59 g·L~(-1) and went up to 49.72 g·L~(-1) steadily in the later stage, and then raised from 0.36 to 0.50 subsequently. Sulfate reduction efficiency improved from 30% to 95%, which was strongly correlated with the MLVSS (r=0.918,p=0.003). Scanning electron microscope analysis showed inoculating sludge was coarse and incompact, and with the dominant species of filamentous bacteria,bacillus,cocci,but granular sludge with dense microorganism community structure were observed, and in which vibrio and bacillus were the dominant species.