腐殖酸含量对污泥厌氧发酵过程产CH4效率的影响

污泥中含有的HA（腐殖酸）会对厌氧发酵过程产生影响.为探究ρ（HA）对厌氧发酵产CH₄效率的影响规律，开展了ρ（HA）为0、200、300和400 mg/L（依次记为T0、T1、T2、T3处理）的中温厌氧发酵模拟试验，检测和分析了φ（CH₄）、累计CH₄产量与产生动力学特征，以及ρ（HA）与累计CH₄产量之间的相关性.结果表明:各处理发酵过程的pH在6.9~7.9之间变化，并且HA对pH变化具有减缓作用；T1处理的φ（CH₄）峰值为66.7%，高于T0处理的61.5%，但随着ρ（HA）的进一步增加，φ（CH₄）峰值逐渐下降为62.0%（T2处理）和60.0%（T3处理）；采用修正Gompertz方程对累计CH₄产量的拟合结果表明，HA对厌氧发酵的产CH₄潜能呈抑制作用，且随ρ（HA）的增加，该抑制作用更加明显，T0、T1、T2和T3处理的最大累计CH₄产量分别为441.1、432.1、397.1和253.5 mL；相关性分析结果显示，ρ（HA）与累计CH₄产量呈负相关，随着ρ（HA）的增加，累计CH₄产量逐渐降低.研究显示，HA对污泥厌氧发酵产CH₄过程呈抑制作用，ρ（HA）较低时可提高沼气中的φ（CH₄）峰值. 

Effect of Humic Acid Content on Methane Production Efficiency during Anaerobic Fermentation of Sludge

Humic acid (HA) in the sludge affects the anaerobic fermentation process. In order to investigate the effect of HA content on the methanogenic efficiency of anaerobic fermentation, mesophilic anaerobic fermentation tests of HA content 0, 200, 300, 400 mg/L (recorded as T0, T1, T2, T3 systems) were conducted. The methane content, cumulative methane yield and production dynamics, as well as the correlation between methane yield and HA content were analyzed. The results showed that the pH in anaerobic fermentation systems with HA changed from 6.9 to 7.9. HA had buffering function on the change of pH value. The peak of methane content in T1 treatment was 66.7%, which was higher than 61.5% of T0. However, with the increase of HA content, the peak of methane content decreased to 62.0% (T2 system) and 60.0% (T3 system). The modified Gompertz equation was used to fit the cumulative methane yield and the results showed that HA inhibited the theoretical methane production of anaerobic fermentation. The inhibition efficiency was more significant with increasing HA, and the theoretical methanogenic potential of T0, T1, T2 and T3 systems were 441.1, 432.1, 397.1 and 253.5 mL, respectively. The correlation analysis showed that the HA content and cumulative methane yield were negatively correlated. The cumulative methane yield gradually decreased with increasing HA. Therefore, HA inhibited methane production during sludge anaerobic fermentation, and the peak of methane content in the biogas increased when the HA content was low.