渗滤液回流条件下多层床厌氧干发酵产气特性

Characteristic of Biogas Production in Multi-layer Anaerobic Dry Fermentation Reactor under Leachate Recirculation Conditions

设计了一种试验规模的多层床式厌氧发酵反应器,以猪粪为发酵底物,稻草为调理料,试验研究在渗滤液回流条件下分层及不同床层厚度对厌氧干发酵产气特性的影响。结果表明:厌氧发酵床分层对原料累计产气量、最大产气量及甲烷体积分数等产气特性均有显著影响。床层厚度由250 mm降为150 mm时,累计产气率由135.7 L/kg增加到172.1 L/kg,提高了26.8%;最高日产气量由97.4 L增加至111.9 L,增加了14.9%,但日均产气量没有明显的变化;最高甲烷体积分数可增加9%,且最高甲烷体积分数出现的时间随床层厚度的降低明显提前。发酵床分层还对渗滤液的pH值和COD值有显著影响,250、200和150 mm 3个不同处理组的pH值从初始值分别升高了8.6%、6.5%和4.8%,COD下降了21.0%、15.0%和14.0%,即床层厚度明显影响渗滤液的入渗和回流效果。

A laboratory scale of multi-layer bed fermentation reactor was designed to study the influences of the layering and thickness on biogas characteristic of dry anaerobic fermentation using pig manure as fermentation substrates and straw as regulate material under the leachate recirculation conditions. The results showed that the bed layer anaerobic fermentation had significant impacts on cumulative gas production, the highest Nissan＇s volume, and methane content in the gas characteristics of raw materials. When the thickness of bed layer changed from 250 mm to 150 mm, the cumulative gas production rate increased from 135.7 L/kg to 172. 1 L/kg, increased by 26.8%. The highest Nissan＇s volume increased from 97.4 L to 111.9 L, arose 14.9% , but had no obvious influences in average daily gas production. The highest methane content could be increased by 9% and the time of highest methane content had been advanced with the decreasing of thickness of bed layer significantly. Stratification of fermentation bed had a significant effect on leachate pH and COD value. With the increases of bed thickness, the pH value of three different groups of thickness treatment, 250, 200 and 150 mm, increased by 8.6% , 6.5% and 4. 8% respectively from the initial value and the COD dropped by 21.0% , 15.0% and 14.0%. The thickness of bed layer affected leachate infiltration and backflow effect significantly.