活性污泥储存与消耗乙酸基质的试验研究与模拟

On the simultaneous storage and growth of the activated sludge with acetate:experiments and modeling

同时贮存与生长理论认为,活性污泥吸收有机碳基质同时用于储存和生长。向SBR反应器投加不同浓度乙酸基质,监测活性污泥氧利用速率(OUR)、聚羟基烷酸盐(PHA)和出水COD的变化,运用活性污泥同时贮存与生长理论分析有机碳储存与消耗过程的特征。结果表明,饱食期结束与COD消耗至最低水平、PHA浓度出现最大值和OUR由最大值急速下降相对应;在饱食阶段,基质贮存OUR是利用外部基质直接生长OUR的2倍。随基质投加历时延长,饱食期平均OUR和最大OUR均下降,PHA产率降低,甚至出现PHA净消耗。因此,基质投加方式对有机碳基质储存与消耗有重要影响。

The aim of this paper is just to study and disclose the underlying mechanism and kinetics models of the activated sludge and make out the influential factors of the feeding pattern on the said storage and growth process.It is for this purpose,we have developed a process of the simultaneous storage and growth in hoping to identify and depict the activated sludge under the aerobic conditions.In so doing,we have explored the specific features of COD storage and its consumption by adding acetate in different concentrations and transition processes from feeding into a sequential batch reactor on the basis of observing and testing the oxygen uptake rate（OUR）,the polyhydroxyalkanoates（PHA） and the chemical oxygen demand（COD）.The results of our experiments and observation demonstrate that the process of storage and growth indeed occur simultaneously during the feeding phase with the internal storage of the expected products from the famine phase even when the PHA drops to the lowest level.And,then,the activated sludge has been going on into the endogenous respiration phase.Furthermore,the working principle of the simultaneous growth and storage model tends to be able to account for the experimental profile both of the OUR and storage products in the form of polyhydroxyalkanoates（PHA）.Moreover,when the feast phase was coming to be over,the consumption of COD would also be getting down to the lowest rate.On the contrary,the PHA tends to increase to its utmost limit with the sharp down of OUR from the maximum limit.Further investigation has disclosed that during the feast period,the OUR of the substrate storage can be done almost twice as fast as that of the substrate consumption for direct growth.And,finally,with the increase of the substrate addition time,an apparent reduction of OUR tends to appear both at the average and maximum levels,with the drop of the yield of PHA and even the consumption of PHA.Thus,it can be seen that the feeding pattern proves to have an important influential effect on the storage and consumption of substrates.Therefore,under the experimental conditions,it would be necessary to control the feeding time for no more than 15 min under the aerobic degradation with acid so as to gain higher yield of PHA.