有机负荷对连续流厌氧发酵产氢系统的影响

Effect of organic loading rate on continuous flow anaerobic activated sludge fermentation system for bio-hydrogen production

以连续流搅拌槽式反应器作为发酵生物制氢反应装置,针对有机负荷(OLR)对厌氧活性污泥发酵生物制氢系统运行的影响进行实验研究.在水力停留时间(HRT)8 h,(35±1)℃,进水COD质量浓度6000 mg/L,即OLR为18 kg/(m3.d)的条件下运行,厌氧活性污泥发酵产氢系统达到稳定时的平均产氢量为10.96 L/d,比OLR 12 kg/(m3.d)条件下提高了19.3%,比OLR 6 kg/(m3.d)条件下提高了52.3%.当进水COD质量浓度达到8000 mg/L,即OLR为24 kg/(m3.d)时,pH、ALK分别从大于4.1和250 mg/L的水平,迅速下降到3.7和5 mg/L以下,而ORP则从-350 mV急速上升到-210 mV以上.表明厌氧活性污泥微生物已无法承受有机负荷提高造成的环境变化,其活性受到严重抑制,反应器产氢能力急剧下降,系统的产酸发酵类型也发生了根本改变.

The effect of organic loading rate on operation of continuous flow anaerobic activated sludge fermentation system for bio-hydrogen production was investigated in a continuous stirred - tank reactor （CSTR）. When influent COD concentration rose to 6000 mg/L （ OLR 18 kg/（ m^3 · d） ） from 4000 mg/ L （OLR 12 kg/（m^3 · d） ） with HRT8 h and （35 ± 1 ） ℃ , pH, ALK and ORP had evidently changed. When the system reached at a new stable state, an average hydrogen evolution rate as high as 10.96 L/d was obtained, which was 19.3% and 52.3% higher than that of OLR 6 kg/（m^3 · d） and OLR 6 kg/ m^3 , respectively. When influent COD concentration rose to 8000 mg/L （ OLR 24 kg/（ m^3 · d） ）, the environment in the reactor changed acutely. The pH and ALK dropped to 3.7 and 5 mg/L from 4. 1 and 250 mg/L, and ORP rose to- 210 mV from -350 mV. The anaerobic activated sludge in the bio -hy- drogen production reactor could not endure these changes, and their activity was inhibited. The hydrogen yield of the reactor dropped quickly, and the organic wastewater fermentation type changed from ethanol type fermentation to mixed acids fermentation.