CSTR和ACR丁酸型发酵制氢系统的运行特性比较

为寻求更好的连续流发酵生物制氢反应器模式，以稀释糖蜜为底物，控制反应系统为丁酸型发酵，比较研究了搅拌槽式反应器（CSTR）和厌氧接触式反应器（ACR）的启动运行特性。结果表明，以经曝气培养的下水道污泥为接种物，在接种量4.8 g MLVSS·L^-1、进水COD 5000 mg·L^-1、HRT 12 h、温度（35±1）℃和pH 5.5～6.0等相同条件下，CSTR系统可以更快地达到稳定的丁酸型发酵状态，而ACR系统因其有效的生物持有能力而在产氢性能方面更具优势。在稳定运行状态下，ACR系统的底物酸化率、产氢速率和污泥的比产氢速率分别为44%、9 L·d^-1和0.15 L·(g MLVSS·d)^-1，分别是CSTR系统的1.62、2.05和1.15倍。

Operation characteristic comparison of CSTR and ACR systems for hydrogen production by butyric acid type fermentation

In order to structure a better continuous flow bioreactor mode for fermentative hydrogen production,a continuous stirred-tank reactor(CSTR)and an anaerobic contact digester(ACR)were evaluated with diluted molasses as raw material,and their operation characteristics during starting and running were analyzed and compared.Inoculated with aerobic pretreated sewage sludge,both the reactors started up at(35±1)℃ with an initial volatile suspended sludge(MLVSS)of 4.8 g·L-1,a hydraulic retention time(HRT)of 12 h and an influent chemical oxygen demand(COD)of 5000 mg·L-1.The pH was controlled at 5.5—6.0 in both fermentation systems during the whole operation period.The results showed that the CSTR could reach steady butyric acid type fermentation in 15 d,much faster than in 25 d for ACR.During the steady state,the butyrate was dominated among the soluble metabolites and counted for 53% and 50% of the total liquid products in CSTR and ACR system,respectively.The hydrogen-producing efficiency was higher for ACR than for CSTR,indicating its better ability to maintain biomass.The substrate acidification ratio,the hydrogen production rate and specific hydrogen productionrate of the sludge were 44%,9 L·d-1 and 0.15 L·(g MLVSS·d)-1,respectively,for the steady ACR system,and 1.62,2.05 and 1.15 times of corresponding values of CSTR system.