【摘要】 HRT的改变可对发酵产氢厌氧活性污泥系统产生多方面的影响.在进水COD质量浓度为6 000 mg/L、35℃、不对进水pH值进行调节等条件下,发酵产氢厌氧活性污泥系统HRT从8 h降低为6 h时,其pH值、ALK分别从4.3和250 mg/L降低为4.2和180 mg/L,ORP从-380~-360 mV升高到-330~-300 mV,生物量虽然从8.7 gVSS/L降低到了7.2 gVSS/L,其产氢能力却从0.14 L/(gVSS.d)提高到0.22 L/(gVSS.d),液相末端发酵产物总量从1 106.1 mg/L增加为1 695.1 mg/L,作为乙醇型发酵目的产物的乙醇和乙酸的含量从90%减少为85%.HRT进一步降低为4 h时,系统内生态条件发生剧烈变化,其pH值、ALK、ORP分别为3.7、75 mg/L和-210 mV,生物量锐减至1.1 gVSS/L,同时乙醇型发酵演替为混合酸发酵,产氢能力下降为零.可见,多种因素可对发酵产氢厌氧活性污泥系统产生影响,而其中HRT是直接可控的第一影响因素.更多还原

【Abstract】 Influences of hydraulic retention time(HRT) on fermentative hydrogen production process by anaerobic activated sludge were investigated.The bioreactor was fed with diluted molasses without adjusting the influent pH.The influent organic wastewater concentration was kept at 6 000 mg COD/L with a temperature of 35 ℃.When the HRT decreased from 8 hours to 6 hours,the pH and ALK of the mixed anaerobic culture decreased from 4.3 and 250 mg/L to 4.2 and 180 mg/L respectively,ORP increased from-380～-360 mV to-330～-300 mV,and the bio-mass decreased from 8.7 gVSS/L to 7.2 gVSS/L,while hydrogen evolution rate increased from 0.14 L/(gVSS·d) to 0.22 L/(gVSS·d),and the fermentative end products such as volatile fatty acids and alcohol increased totally from 1 106.1 mg/L to 1 695.1 mg/L.Among the fermentative end products,as ethanol fermentation type purpose productions,the content of ethanol and acetic acid increased together from 90%to 85%.When HRT decreased further to 4h,pH and ALK of the mixed anaerobic culture decreased respectively to 3.7 and 75 mg/L quickly,while ORP increased to-210 mV.The dramatic change of ecological condition in the bioreactor caused mixed acid-fermentation type instead of ethanol fermentation type,and biomass decreased to 1.1 gVSS/L while hydrogen evolution rate decreased to zero.The results showed that the change of HRT had influence upon the biomass,biological activity and metabolic characteristics of biotic community of the anaerobic activated sludge system.HRT was the first influence factor that can be controlled.更多还原