Krist Gernaey A, Petersen B, Ottoy J P, Vanrolleghem P
BIOMATH Department, Ghent University, Coupure Links 653, B-9000 Gent, Belgium.
Water Res. 2001 Apr;35(5):1280-94. doi: 10.1016/s0043-1354(00)00366-3.
A short review of different respirometric methods is presented, and advantages and disadvantages of different principles are discussed. In this study a combined respirometric-titrimetric set-up was applied to monitor the degradation processes during batch experiments with activated sludge. The respirometer consists of an open aerated vessel and a closed non-aerated respiration chamber. It is operated with two oxygen probes resulting in two sources of information on the oxygen uptake rate; both collected at a high frequency. The respirometer is combined with a titrimetric unit that keeps the pH of the activated sludge sample at a constant value through the addition of acid and/or base. The cumulative amount of added acid and base serves as a complementary information source on the degradation processes. Interpretation of respirometric data resulting from validation experiments (additions of acetate and urea as ammonium source) showed that the set-up provided reliable data. Data interpretation was approached in two ways: (1) via a basic calculation procedure, in which the oxygen uptake rates were obtained by an oxygen mass balance over the respiration chamber, and (2) via a model-based procedure in which substrate transport was included for a more accurate data interpretation. Simulation examples showed that the presence of substrate transport in the model may be crucial for a correct data interpretation, since experimental conditions (e.g. low flow rate) and/or the biodegradation kinetic parameters (e.g. high Ks) may otherwise lead to data interpretation errors. Earlier studies already pointed out that titrimetric data can be related to nitrification, and this was also confirmed in this study. However, in addition, it was shown here for experiments with acetate that the amount of acid dosed was clearly related to the amount of acetate degraded. This indicates that the titrimetric data can be used to study the carbon source degradation. For the titrimetric data in this study, a model-based analysis was however only applied for the nitrification process. For an experiment with ammonium, it was illustrated that the estimation of biodegradation kinetics on a combined respirometric-titrimetric data set significantly improves confidence intervals of the parameters compared to the parameter estimation based on respirometric or titrimetric data separately.
本文简要回顾了不同的呼吸测定方法，并讨论了不同原理的优缺点。在本研究中，采用了一种呼吸测定-滴定法联合装置来监测活性污泥间歇实验过程中的降解过程。该呼吸仪由一个开放式曝气容器和一个封闭式非曝气呼吸室组成。它通过两个氧探头运行，从而得到关于氧摄取率的两个信息源；两者均以高频采集。该呼吸仪与一个滴定装置相结合，通过添加酸和/或碱使活性污泥样品的pH值保持恒定。添加酸和碱的累积量作为降解过程的补充信息源。对验证实验（添加乙酸盐和尿素作为铵源）所得呼吸测定数据的解释表明，该装置提供了可靠的数据。数据解释采用两种方法：（1）通过基本计算程序，其中通过呼吸室的氧质量平衡获得氧摄取率；（2）通过基于模型的程序，其中包括底物传输以进行更准确的数据解释。模拟示例表明，模型中底物传输的存在对于正确的数据解释可能至关重要，因为实验条件（例如低流速）和/或生物降解动力学参数（例如高Ks）否则可能导致数据解释错误。早期研究已经指出滴定数据可能与硝化作用有关，本研究也证实了这一点。然而，此外，本研究还表明，对于乙酸盐实验，添加的酸量与降解的乙酸盐量明显相关。这表明滴定数据可用于研究碳源降解。然而，对于本研究中的滴定数据，仅对硝化过程进行了基于模型的分析。对于铵实验，结果表明，与分别基于呼吸测定或滴定数据的参数估计相比，基于呼吸测定-滴定法联合数据集对生物降解动力学的估计显著改善了参数的置信区间。
