Advanced And Aerobic Treatment Of Molasses Alcohol Wastewater After Anaerobic Digestion

Molasses alcohol wastewater is a kind of wastewater with high COD and complex organic ingredients.It is hard to purify with anaerobic fermentation alone.Based on the anaerobic fermentation from our lab,the research of advanced treatment was implemented to investigate the effect of serving microorganisms from different sources and metal ions in during the aerobic fermentation process,to provide theoretical and technical basis for molasses alcohol wastewater purification.The experiments undergone in lab scale,temperature as room temperature,working volume of the reactors as 5 L,sludge inoculation size as one third of the total volume,three parallels with every step.One-time feeding mode,operation is 8 h,including 6.5 h of aeration,30-35 min of precipitation,5 min of drainage,50 min of static settlement.Aeration place at the bottom of the sludge,with tray aerators.Aerating amount at DO(dissolved oxygen)approx.2 mg/L.For the purpose of intensifying the treatment effect,outer microorganisms sources that take part as one fifth of total sludge were feaces of cow,chicken and pig.The COD removals were 46%,54%and 57%respectively,blank control was 52%.For the active sludge with pig feaces added,6 strains could use molasses alcohol wastewater as sole carbon source were isolated,identified as Bacillus cereus,Proteus,Acinetobacter,Exiguobacterium,Pseudomonas and Comamonas.These strains were cultured and mixed,then inoculated into the aerobic reactors with 5%of waste water volume after the acclimation,the average COD removing rate was 60%when the reactor stayed stable.The influence of Fe3+ and Mg2+ toward the active sludge acclimation was also investigated.Different concentration as:0 mg/L,10 mg/L,50mg/L and 100 mg/L.The results showed that minimal impact for both ions when at low concentrations,while at 100 mg/L the COD removing rate was 57%with aerobic process.The data explained no perceivable effect was Fe3+ and Mg2+.The iron-carbon micro-electrolysis,Fenton system,and their combination treatment were implemented for the more advanced wastewater treatment,conveyed by the single factors experiments and the orthogonal experiments.When the reaction system was 200 mL,the optimized indexes for those treatment methods were:iron-carbon micro-electrolysis,pH at 3,3 g iron shred,ratio of iron-carbon was 1:1,reaction time was 6 h,the COD removal ratio was 40 ±2.66%;Fenton system's pH at 4,3.5 mL H2O2,1.5 mL10%FeSO4,reaction time was 40 min,the COD removal ratio was 76.49 ± 1.75%.The combination method was the optimizing with Fenton system that based on the iron-carbon micro-electrolysis method,its optimized indexes were pH at 4,3.5 mL H2O2,1 mL10%FeSO4,reaction time was 30 min.Under the optimized condition,the COD removal ratio was 66.57 ± 0.95%.The experiment provided reference for the advanced aerobic treatment for wastewater.