生物沥浸对牛粪沼液脱水性能的影响研究

Influence of Bioleaching on Dewaterability of Cattle Biogas Slurry

采用嗜酸性硫杆菌,通过摇瓶试验研究了不同硫杆菌及其复合生物沥浸对含固率为3.4%的沼液脱水性能的影响.设置了如下5个处理:①原始沼液(作对照);②4 g.L-1 Fe2+(不接菌);③2 g.L-1S0+25 mL A.t;④4 g.L-1Fe2++25 mL A.f;⑤2g.L-1 S0+4 g.L-1 Fe2++12.5 mL A.t+12.5 mL A.f.考察了不同的处理生物沥浸过程中的pH、Fe2+、Fe3+、总Fe、比阻、毛细吸水时间(CST)、沉降性能及沉降12 h后上清的浊度等的变化.结果表明,原始沼液+Fe2+、原始沼液+Fe2++A.f和原始沼液+Fe2++S0+A.f+A.t这3个处理沼液的比阻和CST都得到了不同程度的降低,综合沼液的脱水性能、沉降性能以及沉降12 h后的上清液浊度,结合经济成本分析,建议选择原始沼液+Fe2++A.f作为沼液生物沥浸处理比较合理.生物沥浸后沼饼中的有机质、N、P、K的含量分别降低了1.14%、0.09%、0.05%、0.1%,不影响肥效,对沼饼中的重金属Cu、Zn的去除率分别为63.2%和91.3%,同时对沼液中的总大肠杆菌的杀灭率超过了99%.可见,生物沥浸技术为沼液的资源化利用提供了一个全新的途径.

The dewaterability of cattle biogas slurry facilitated by bioleaching was investigated through batch experiments with co-inoculation of different Acidophilic thiobacilli（Acidithiobacillus thiooxidans TS6 or Acidithiobacillus ferrooxidans LX5）.The experiment was set the following 5 treatments：①original biogas slurry（CK）,②4 g·L-1 Fe2＋（uninoculation）,③2 g·L-1 S0＋25 mL A.t,④4 g·L-1 Fe2＋＋25 mL A.f and ⑤2 g·L-1 S0＋4 g·L-1 Fe2＋＋12.5 mL A.t＋12.5 mL A.f.During bioleaching,dynamic changes of pH,ORP,Fe2＋,Fe3＋,total Fe,the settleability,the turbidity of the supernatant after settling for 12 h,and the dewaterability（expressed as specific resistance to filtration γ or capillary suction time,CST） of biogas slurry were monitored.Results show that specific resistance γ and CST of bioleached biogas slurry are reduced drastically for the treatments of original biogas slurry spiked with only Fe2＋,the treatment of original biogas slurry co-spiked with Fe2＋ and Acidithiobacillus ferrooxidans LX5,and the treatment of original biogas slurry co-spiked with Fe2＋,S0 and two Acidophilic thiobacilli.Taking the dewaterability,settleability,the turbidity of the supernatant fluid after settle 12 h and economical cost into account,the treatment of original biogas slurry co-spiked with Fe2＋ and Acidithiobacillus ferrooxidans LX5 is the most suitable pattern for cattle biogas slurry bioleaching.After bioleaching,1.14% of organic matter,0.09% of N,0.05% of P,and 0.1% of K are lost in the bioleaching process,but it don＇t affect its fertilizer efficiency.Meanwhile,the 63.2% of Cu and 91.3% of Zn are removed from the biogas slurry,and elimination efficiencies of total coliforms in bioleached slurry exceed 99%.This study might provide a new approach for treatment and disposal of biogas slurry.