变频控制DO下SBR硝化反应控制参数及节能的中试研究

根据微生物好氧反应的需氧量调节曝气量在当今能源紧缺的形势下具有十分重要的意义.为了研究曝气量大小对SBR实时控制参数pH、DO的影响,采用变频器调节曝气量以控制系统不同的DO浓度,以60 m3中试SBR反应器处理北京市北小河污水处理厂城市污水,考察了硝化过程中pH值、DO与有机物去除及硝化过程的相关性,并引入了新的控制参数--变频频率f.试验结果表明,控制溶解氧浓度较低时,pH值不能作为硝化结束的控制参数,但可根据变频频率f的特征点判断硝化反应的结束;控制溶解氧为3.0 mg/L和4.0 mg/L时,DO、pH值、变频频率f都可作为硝化结束的控制参数,同时,变频控制可有效降低单位时间内风机的能耗.

A pilot scale research on nitrification control parameters and energy saving by applying frequency conversion technology on controlling DO of SBR

The adjustment of aeration rate based on the oxygen demand of microorganism in aerobic reaction is very critical under the condition of current energy shortage. In order to investigate the effect of aeration rate adjustment on the controlling parameters of SBR, such as pH value and DO, frequency converter was used to adjust the aeration rate and control DO at different levels. 60 m³ volume SBR reactor was used to treat the domestic wastewater of Beixiaohe WWTP in Beijing. It was investigated that the relationship between the parameters such as pH value and DO in the nitrification process and the process of organic degradation and nitrification. A new control parameter-frequency of frequency converter, called f for short, was also introduced. According the results, when the controlled DO concentration is low, the pH value could not be used as control parameter of nitrification completion, but the judgment of the complete nitrification could be based on the frequency. When the DO concentration was controlled at 3.0 mg/L and 4.0 mg/L respectively, DO, pH value and frequency of converter could be used as the control parameters of complete nitrification. The frequency controlling can also decrease the energy consumption of the blower per hour effectively.