空气提升式反应器处理制革污泥的中试研究

Removal of Cr from Tannery Sludge by Bioleaching in Air-lift Reactor:A Pilot Study

设计了1个280 L空气提升式生物沥浸反应器,利用特异嗜酸性硫杆菌为主的微生物复合菌群对制革污泥进行了较长期的（连续运行43批次）生物沥浸脱铬试验.研究了1.0-3.0 m^3/h不同通气量对生物沥浸法脱铬效率的影响.结果表明,不同处理条件下污泥均能快速充分混匀,通气量不足1.5 m^3/h时经过至少90 h才可获得80%以上的Cr溶出率.综合多因素考虑,本试验规模下通气量为2.0 m^3/h较为合适,72 h Cr溶出率可达92.5%.研究还发现,在通气量为2.0 m^3/h或以上时,体系溶氧值随pH值的下降而明显上升,最终DO可达到5 mg/L以上.因此,在工程化运行中可在每个沥浸周期的后期调低ALR反应器的供气量,控制DO值在2.0 mg/L左右满足LX5和TS6菌的生长需求即可,以此控制运行成本.

A bioleaching process performed in 280 L air-lift reactor was developed for extracting Cr from tannery sludge.Cr removal efficiency under different aeration amount with a range from 1.0m^3/h to 3.0m^3/h was investigated.The results showed that the sludge could be homogeneous quickly for different aeration treatment even if aeration amount was as low as 1.0m^3/h. But the obvious effect of aeration amount on pH decrease and subsequent Cr dissolution in tannery sludge during bioleaching was observed.If the aeration amount was below 1.5m^3/h,it at least took 90 h to reach 80% Cr removal efficiency.In the light of Cr removal efficiency and energy consume,the aeration amount of 2.0m^3/h was considered as an optimum one for bioleaching in this trial.Cr removal efficiency could reach above 92.5% at 72 h.In the sludge bioleaching system dissolved oxygen increased obviously with the decrease of pH.Eventually,dissolved oxygen rised to 5mg/L or more when aeration amount was maintained at 2.0m^3/h or more .Therefore,it was suggested that the aeration amount in ALR could be adjusted to a lower level in the late stage of tannery sludge bioleaching in order to save operation cost.