降流式厌氧紊动床COD去除与生物膜厚度及密度的关系研究

Relations Between COD Removal and Biofilm Thickness and Density of Downflow Anaerobic Turbulent Bed

介绍了一种用沼气强制循环使悬浮载体颗粒流化的反应器———降流式厌氧紊动床 .在COD有机负荷为 6～ 2 2kg/m3·d- 1、水力停留时间为 0 .2 5～ 0 .94d下 ,CODCr去除率保持在 6 5%～ 85% .此时生物膜厚度相对较低 (5～ 30 μm) ,而生物膜密度达到较高水平 (VSS >70g/L) .试验发现 ,生物膜厚度及密度的变化与COD去除呈相反变化 .反应器里高水平的生物活性表明 :剧烈紊动和剪切有利于微生物生长并形成薄的、致密的活性膜 ;

A reactor,called a downflow anaerobic turbulent bed,is introduced,in which the circulation is forced by biogas to ensure fluidization of floating carrier particles.When the operational range of the reactor is 6 22?kg/(m 3·d) and the hydraulic retention time 0.25～0.94?d,the COD Cr removal efficiency remains 65%～85%,and the bio film thickness is rather small(5～30?μm),while the bio film density is high (>70?g/L).Experimental results show that the biofilm thickness and density increase with the decrease of COD removal.Bioactivity kept at a high level in the reactor indicates that violent turbulence and shear are beneficial for the growth of microbe and the formation of a thin,dense and active film.Meanwhile,the volatile solid detachment at a high organic loading rate (OLR) increases quasi linearly with COD removal and with the decrease of the amount of solid in the reactor.