EGSB反应器的低温运行性能研究

Research on the EGSB reactor's characteristic low temperature operations

对膨胀颗粒污泥床(EGSB)反应器在低温(10～15℃)条件下的运行状况和污泥特性进行研究。结果表明,EGSB反应器在10～15℃的低温条件下能够稳定高效运行。当进水COD质量浓度低至114 mg/L或高达3 600 mg/L(有机负荷高达23 kg COD·m^(-3)·d^(-1))时,COD去除率均能维持在70%左右。与中温(32～35℃)相比,低温时颗粒污泥的沉速相对较低,但不低于15 m/h,不会被冲出反应器而造成污泥流失。低温时,颗粒污泥的产甲烷活性明显降低,COD去除率也明显降低,但液体上升流速的提高能改善泥水的传质效果,提高COD去除率。在HRT=0.9h、液体上升流速V_(up)=3.0 m/h左右的运行条件下,反应器内温度由35℃降到15℃时,K由0.391×10~3降到0.107×10~3,COD去除率由84.32%降到68.9%。但当V_(up)由3.0 m/h提高到4.2 m/h时,K由0.107×10~3提高到0.254×10~3,COD去除率也由68.9%提高至76.7%。低温时,EGSB反应器的抗温度冲击能力很强。低浓度时,EGSB反应器的抗pH冲击能力不强,但随着进水COD浓度的提高,其抗pH冲击能力逐渐增强。EGSB反应器在低温低浓度条件下运行时需添加碱度以维持反应器内适宜的pH值。

This paper has done an investigation and research on the EGSB reactor＇s working performance at low temperatures around 10 - 15 ℃ . The results of research prove that the EGSB reactor can be expected to help stabilize the operation efficiency at about a low temperature of 10 ℃ . Tile COD removal efficiency can also be made to increase to about 70% with the COD concentration dropping to 114 mg/l, or rising to 3 500 mg/L （23 kg COD· m^-3·d^-l organic loads）. The settled velocity of the granules in such low temperatures can also be tolerable to medimn temperatures, but not over the limit of 15 m/h so as not for the sludge to be washed out from the reactor. Nevertheless, it should be pointed out that lowering the operation temperature is still likely to lead to an obvious decrease in the granular methanogenlc activity＇ and COD＇s removal efficiency, because the increase of temperature helps to speed up the liquid up-flow velocity and improve the mass-transfer as well as the COD removal efficiency. On the contrary, lower operation temperature may result in distinctive drop of the rate constant. In the conditions of 0.9 h HRT and at about 3.0 m/h liquid up-flow velocity, the rate constant K and the COD removal efficiency is likely to drop from 0.391 × 10^3, 84.32% to 0. 107 × 10^3, 68.9% respectively with the performance temperature of the EGSB reactor reduced from 35 ℃ to 15 ℃. But with the increase of the liquid up-flow velocity from 3.0 m/h to 4.2 m/h, the rate constant K and the COD removal efficiency can be expected to increase from 0. 107 × 10^3, 68.9% to 0.254 × 10^3, 76.70% . On the condition of low temperature at about 10 ℃ , the EGSB reactor may have strong ability to support the temperature shock. Although it has a low supporting pH shock ability at low temperatures, its sup- porting pH shock ability may get stronger with the influent COD increase even at low concentration. Thus it is necessary for the reactor to keep proper pH value so as to supply sufficient alkalinity.