Banks C J, Koloskov G B, Lock A C, Heaven S
Department of Civil & Environmental Engineering, University of Southampton, Southampton SO17 1BJ, UK.
Water Sci Technol. 2003;48(2):189-96.
The paper considers factors that determine the oxygen balance in extreme climate waste stabilisation ponds during the critical spring warm-up period. At this time BOD load on the pond is a maximum, due to accumulation of wastewater under the ice during the winter. The paper describes the operation of a typical cold climate WSP and the events leading to a balanced steady state system as spring develops into summer. A mathematical model to simulate conditions within a batch fed experimental pond over the transient period is described. To model temperature changes in the water body experimental data were fitted to a generalised equation based on diurnal fluctuations in air temperature. The results are plotted in a normalised form and show the diurnal fluctuation and time lapse as the depth of the pond increases. Maximum daily water temperature lags behind maximum light intensity. Bacterial growth is simulated by a Monod kinetic model in which growth rate depends on initial substrate concentration; temperature compensation is applied using a temperature activity coefficient. Oxygen utilisation is calculated from substrate removal. Algal growth rate is more complicated as it is affected by temperature and light availability. Algal oxygen production potential is considered in terms of its primary metabolite yield, which is then used in a Monod equation to estimate the growth rate. The model uses a mass balance approach to determine dissolved oxygen concentration in the pond. The model is still in a simple form but shows reasonable agreement, in terms of events and time lapses, to measured parameters in experimental ponds recovering from ice cover.
本文探讨了在关键的春季升温期，极端气候条件下的废物稳定塘中决定氧平衡的因素。此时，由于冬季冰层下废水的积累，池塘的生化需氧量负荷达到最大值。本文描述了典型寒冷气候下废物稳定塘的运行情况，以及随着春季向夏季发展，该系统达到平衡稳态的过程。文中介绍了一个用于模拟间歇进料实验塘在过渡期间内情况的数学模型。为了模拟水体中的温度变化，将实验数据拟合到一个基于气温日波动的广义方程中。结果以归一化形式绘制，显示了随着池塘深度增加，日波动和时间推移情况。每日最高水温滞后于最大光照强度。细菌生长通过莫诺德动力学模型进行模拟，其中生长速率取决于初始底物浓度；使用温度活性系数进行温度补偿。根据底物去除量计算氧气利用率。藻类生长速率更为复杂，因为它受温度和光照可用性的影响。藻类产氧潜力根据其初级代谢产物产量来考虑，然后将其用于莫诺德方程以估计生长速率。该模型采用质量平衡方法来确定池塘中的溶解氧浓度。该模型仍处于简单形式，但就事件和时间推移而言，与从冰封状态恢复的实验塘中的测量参数显示出合理的一致性。
