Liu Yu, Wang Zhi-Wu, Liu Yong-Qiang, Qin Lei, Tay Joo-Hwa
Division of Environmental and Water Resources Engineering, School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798.
Biotechnol Prog. 2005 Mar-Apr;21(2):621-6. doi: 10.1021/bp049674u.
Aerobic granulation is a novel biotechnology recently receiving intensive research attention. Aerobic granules developed in SBR can be as big as several millimeters, thus the traditional models describing the settling velocity of activated sludge are no long valid in aerobic granules culture. In this study, a new type of model was developed for the settling velocity of aerobic granules. This model shows that the settling velocity of aerobic granules is the function of SVI, mean size of granules and biomass concentration of granules. When the size of bioparticle is small enough, the proposed model reduces to the well-known Vesilind equation. Results indicated that the proposed model could satisfactorily fit experimental results obtained in the course of aerobic granulation under different conditions, while the Vesilind equation failed to or very poorly fit the experimental data. In addition, the proposed model can also be extended to anaerobic granules. The settling velocity is one of the most important parameters in both aerobic and anaerobic granulation, and successful biogranulation is highly related to the manipulation of settling velocity. It was demonstrated that the proposed model can sever as a useful tool for design and operation engineers to properly select the settling velocity for enhanced aerobic and anaerobic granulation.
好氧颗粒化是一种最近受到广泛研究关注的新型生物技术。在序批式反应器（SBR）中形成的好氧颗粒可以达到几毫米大小，因此传统描述活性污泥沉降速度的模型在好氧颗粒培养中不再适用。在本研究中，针对好氧颗粒的沉降速度开发了一种新型模型。该模型表明，好氧颗粒的沉降速度是污泥容积指数（SVI）、颗粒平均尺寸和颗粒生物量浓度的函数。当生物颗粒尺寸足够小时，所提出的模型简化为著名的维西林德方程。结果表明，所提出的模型能够很好地拟合在不同条件下好氧颗粒化过程中获得的实验结果，而维西林德方程不能拟合或非常差地拟合实验数据。此外，所提出的模型还可以扩展到厌氧颗粒。沉降速度是好氧和厌氧颗粒化过程中最重要的参数之一，成功的生物颗粒化与沉降速度的控制密切相关。结果表明，所提出的模型可以作为设计和运行工程师的有用工具，以便正确选择沉降速度以强化好氧和厌氧颗粒化。
