| The impact of biochar on the performance of water treatment systems has attractedwide attention of environmental protection workers.In this paper,biochar was added into the activated sludge system,the impact of biochar on the performance of activated sludge were determined by monitoring the changes of biomass,nitrogen and phosphorus removal efficiency,the composition and content of SMP and EPS components in sludge during the operation process.The adsorption and removal efficiency of the activated sludge system for different metal ions.At the same time,the effects of biochar on activated sludge performance under metal ion stress were also studied.The results provide a theoretical reference for the application of biochar in water treatment.（1）Three biochar prepared from three different raw materials was added into the SBR system.After operation,it was found that the addition of biochar increased the volume of sludge flocs,increased microbial content,and better settling performance.The addition of biochar to activated sludge has a better effect of removing nitrogen,and at the same time improves the ability to remove phosphorus.Compared with the control group,the content of SMP in activated sludge added with biochar was reduced.Among them,the protein content of SMP with activated PMB was reduced by 76.6%,and the addition of RSB and RHB decreased by 64.6%and 62.3%respectively.It was conducive to improving the quality of sewage effluent and reducing the COD content of the effluent.However,the content of protein in EPS increased by 17.8%～32.8%,which may be because the addition of biochar increased the microbial content of the sludge.EPS contains more amino acids or tryptophan,tyrosine and phenylalanine in protein.The addition of pig manure biochar（PMB）has the greatest impact on the activated sludge system,followed by straw biochar（RSB）and rice husk biochar（RHB）,which may be related to the different physical and chemical properties of biochar made from different raw materials.（2）The effect of biochar on the adsorption and removal of heavy metal ions by activated sludge:The adsorption of heavy metal ions by activated sludge with biochar was significantly stronger than that of the control group.Among them,the activated sludge with pig manure biochar（PMB）had the strongest adsorption of heavy metal ions,activated sludge with straw biochar（RSB）and rice husk biochar（RHB）followed.The activated sludge added with pig manure biochar（PMB）has the strongest adsorption of Cu2+among the three metal ions(Cr6+,Cu2+,Zn2+),and the removal rate is as high as 92.87%.（3）The effect of pig manure biochar（PMB）on activated sludge when the simulated sewage contains Cu2+:When the simulated sewage contains Cu2+,the boundary of activated sludge was not clear,the sludge flocculation was poor,and there was no obvious sign of microbial activity.The addition of PMB plays a role in linking the sludge flocs,the volume of the sludge flocs increases,the settling performance was improved to a certain extent,and the microbial biomass increases（about 10%increase）.The presence of PMB improves the removal rate of ammonia nitrogen and TN by the sludge,and the removal capacity of phosphorus has also been improved to a certain extent.At the same time,the addition of PMB activated sludge has a higher removal efficiency of copper ions.Activated sludge SMP contains a large amount of humus under copper ion stress,accounting for about 45.5%of the total SMP.The addition of PMB reduces the SMP content of activated sludge,COD of the effluent was lower,and it was easier to reach the discharge standard.The total amount of EPS in the control group was greater than that in the test group with PMB added,but the protein content of EPS in PMB-added activated sludge was 15.5%higher than that in the control group.The reason may be that the activated sludge with PMB had a higher microbial biomass. |
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