| 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-1S0 +25 mL A.t ,④4 g·L-1Fe2++25 mL A.f and ⑤2 g·L-1S0 +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. |
