Wichern M, Lübken M, Horn H
Institute of Water Quality Control, Technical University of Munich, Am Coulombwall, 85748, Garching, Germany.
Water Sci Technol. 2008;58(6):1199-206. doi: 10.2166/wst.2008.486.
The biological wastewater treatment using aerobic granular sludge is a new and very promising method, which is predominantly used in SBR reactors which have higher volumetric conversion rates than methods with flocculent sludge. With suitable reactor operation, flocculent biomass will accumulate into globular aggregates, due to the creation of increased substrate gradients and high shearing power degrees. In the research project described in this paper dairy wastewater with a high particle load was treated with aerobic granular sludge in an SBR reactor. A dynamic mathematical model was developed describing COD and nitrogen removal as well as typical biofilm processes such as diffusion or substrate limitation in greater detail. The calibrated model was excellently able to reproduce the measuring data despite of strongly varying wastewater composition. In this paper scenario calculations with a calibrated biokinetic model were executed to evaluate the effect of different operation strategies for the granular SBR. Modeling results showed that the granules with an average diameter of 2.5 mm had an aerobic layer in between 65-95 microm. Density of the granules was 40 kgVSS/m3. Results revealed amongst others optimal operation conditions for nitrogen removal with oxygen concentrations below 5 gO2/m3. Lower oxygen concentrations led to thinner aerobic but thicker anoxic granular layers with higher nitrate removal efficiencies. Total SBR-cycle times should be in between 360-480 minutes. Reduction of the cycle time from 480 to 360 minutes with a 50% higher throughput resulted in an increase of peak nitrogen effluent concentrations by 40%. Considering biochemical processes the volumetric loading rate for dairy wastewater should be higher than 4.5 kgCOD/(m3d). Higher COD input load with a COD-based volumetric loading rate of 9.0 kgCOD/(m3d) nearly led to complete nitrogen removal. Under different operational conditions average nitrification rates up to 5 gNH/(m3h) and denitrification rates up to 3.7 gNO/(m3h) were achieved.
采用好氧颗粒污泥进行生物废水处理是一种全新且极具前景的方法，主要应用于序批式反应器（SBR）中，该反应器的体积转化率高于使用絮凝污泥的方法。通过合适的反应器运行方式，由于底物梯度增加和高剪切力的作用，絮凝生物质会聚集形成球状聚集体。在本文所述的研究项目中，采用SBR反应器中的好氧颗粒污泥处理了高颗粒负荷的乳制品废水。开发了一个动态数学模型，更详细地描述了化学需氧量（COD）和氮的去除以及典型的生物膜过程，如扩散或底物限制。尽管废水成分变化很大，但校准后的模型能够出色地重现测量数据。本文利用校准后的生物动力学模型进行了情景计算，以评估颗粒SBR不同运行策略的效果。建模结果表明，平均直径为2.5毫米的颗粒具有65至95微米厚的好氧层。颗粒密度为40千克挥发性悬浮固体/立方米。结果还揭示了在氧气浓度低于5克氧气/立方米时氮去除的最佳运行条件。较低的氧气浓度导致好氧颗粒层变薄，但缺氧颗粒层变厚，硝酸盐去除效率更高。SBR的总循环时间应在360至480分钟之间。将循环时间从480分钟减少到360分钟，同时通量提高50%，导致氮排放峰值浓度增加40%。考虑到生化过程，乳制品废水的体积负荷率应高于4.5千克化学需氧量/（立方米·天）。基于化学需氧量的体积负荷率为9.0千克化学需氧量/（立方米·天）的更高化学需氧量输入负荷几乎实现了完全脱氮。在不同运行条件下，实现了高达5克氨氮/（立方米·小时）的平均硝化速率和高达3.7克硝酸盐氮/（立方米·小时）的反硝化速率。
