The present paper investigates the effect of dilution rate on the removal of total chemical oxygen demand and nitrate in the draft tube spouted bed reactor and morphological characteristics of biofilms formed by microorganisms of mixed culture on granular activated carbon (GAC). The nitrate and total chemical oxygen demand (COD) decreased from 97 to 81% and 95% to 87% respectively with increase in dilution rate from 0.6/h to 1.5/h showing that residence time in the reactor governs the nitrate and total COD reduction efficiency. Lower dilution rates favor higher production of biomass and extracellular polymeric substances (EPS). It was observed that the nitrate and total COD reduction rate increased with time along with simultaneous increase in EPS production. Thus, the performance of a reactor in terms of dynamic and steady-state biofilm characteristics associated with nitrate and organic reduction is a strong function of dilution rate. Hence these findings indicate that a draft tube spouted bed reactor is capable of simultaneously reducing total organics and nitrogen in industrial/municipal wastewater, as this reactor possesses two distinct regions aerobic and anoxic conditions which can prevail in different parts of a reactor.

本文研究了稀释率对尾流管喷射床反应器中总化学需氧量和硝酸盐去除的影响，以及微生物在颗粒活性炭（GAC）上混合培养形成的生物膜形态特征。随着稀释率从 0.6/h 增加到 1.5/h，硝酸盐和总化学需氧量 (COD) 分别从 97% 减少到 81% 和 95% 到 87%，这表明反应器中的停留时间决定了硝酸盐和总 COD 的减少效率。较低的稀释率有利于生物质和细胞外聚合物 (EPS) 的更高产量。据观察，硝酸盐和总 COD 的减少率随着时间的推移而增加，同时 EPS 产量也增加。因此，在与硝酸盐和有机物还原相关的动态和稳态生物膜特性方面，反应器的性能是稀释率的重要函数。因此，这些发现表明，尾流管喷射床反应器能够同时减少工业/市政废水中的总有机物和氮，因为该反应器具有两个不同的区域，即在反应器的不同部分普遍存在的好氧和缺氧条件。