有机负荷对鸡粪厌氧发酵产气特性及其动力学的影响

Effect of Organic Loading Rate on Characteristics and Kinetics of Anaerobic Digestion of Chicken Manure

[目的]研究有机负荷对鸡粪厌氧发酵过程中产气特性及其产气动力学的影响。[方法]在中温条件(37±1)℃下采用半连续搅拌反应器(CSTR)进行研究。[结果]有机负荷为2.5~5.3 g VS/(L·d)时,厌氧消化系统中氨氮浓度低于6.7 g/L,沼气最大容积产气率为2.58 L/L;同时有机酸浓度也处于较低范围。然而,当有机负荷提高到6.0 g VS/(L·d)时,氨氮浓度升高到6.7 g/L时引起了乙酸(>7 000 mg/L)和丙酸(>1 900 mg/L)的快速累积,沼气容积产气率也降低了23.5%。通过基质平衡动力学分析得出,鸡粪中温厌氧消化的基质转化为沼气(YS/G)和甲烷(YS/M)的比例系数分别为1.085 7和1.686 1 g VSremoved/L。[结论]该研究可为高氨氮浓度鸡粪沼气工程的稳定运行提供科学依据。

[Objective]To investigate the effects of organic loading rates( OLRs) on the performance and kinetics of mesophilic anaerobic digestion of chicken manure.[Method]The experiments were carried in a laboratory-scale semi-continuously stirred tank reactor under mid-temperature condition( 37 ± 1) ℃.[Result]The results indicated that as the OLRs located in the range of 2. 5-5. 3 g VS/( L·d),the ammonia concentration and volume biogas production rate( VBPR) was less than 6. 7 g/L and 2. 58 L/L,respectively. In addition,no significant volatile fatty acids accumulation was observed during this period. However,as the OLRs raised to 6. 0 g VS/( L·d),the ammonia concentration climbed to 6. 7 g/L,which caused the VBPR decreased by 23. 5%. The high concentration of ammonia also contributed to the sharply accumulation of acetate( >7 000 mg/L) and propionate( >1 900 mg/L). According to the substrate balance model,the conversion coefficient of substrate into biogas( YS/G) and methane( YS/M) was 1. 085 7 g VSremoved/L biogas and 1. 686 1 g VSremoved/L CH4,respectively.[Conclusion]This study can provide scientific basis for stable operation of chicken manure biogas project with high concentration of ammonia nitrogen.