| Because most of the existing wastewater treatment processes cannot effectively remove pharmaceuticals and personal care products（PPCPs）,a large number of PPCPs are discharged into the water environment through sewage treatment plants every year,which harms the water ecological environment.In this study,a hybrid moving bed biofilm reactor-membrane bioreactor（MBBR-MBR）was constructed to enhance the removal of PPCPs,and the mechanism of its degradation of PPCPs was explored.At the same time,the operation conditions were regulated to improve the removal effect of PPCPs and alleviate membrane fouling.The main research contents and results of this paper are summarized as follows:（1）The MBBR-MBR coupling system was constructed,and the removal efficiency of conventional pollutants and the performance of simultaneous nitrification and denitrification（SND）of the hybrid system were analyzed under different C/N ratios.The results show that in the absence of PPCPs,the C/N ratio has little effect on the removal rate of NH4+-N and total organic carbon（TOC）,both of which can reach more than 99%and 88%,and the C/N ratio mainly affects the denitrification in the system.In the presence of single sulfadiazine antibiotic（SDZ）,the removal rates of TOC,NH4+-N and TN as well as the SND effect were affected by the C/N ratio,and the system operating performance was more stable under high C/N.When different PPCPs coexist,the system is more impacted by SDZ.In any case,both ammonia nitrogen and total nitrogen in the effluent water of the MBBR-MBR coupling system can meet Grade A standard.（2）The effect and mechanism of enhanced removal of PPCPs in MBBR-MBR coupling system were investigated.The results showed that the removal efficiency of SDZ was influenced by the C/N ratio.The removal efficiency of SDZ under high C/N and low C/N conditions was 74.82±7.72%（C/N=9）and 56.19±3.87%（C/N=2.5）,respectively.At low C/N ratio（2.5）,the coupling system had the highest removal rate of ibuprofen（79.62±6.95%）.Compared with single PPCPs,the coupling system had a lower removal rate of ibuprofen（IBU）when two PPCPs coexisted.According to the analysis of PPCPs removal pathway,biodegradation is the main way of PPCPs degradation in the coupling system.High-throughput sequencing of 16S r RNA indicated that the activity and biodiversity of nitrifying bacteria were affected in the presence of SDZ,and this negative effect was particularly obvious at low C/N.（3）The sludge particle size and the composition of the filter cake layer in the MBR unit were compared and analyzed,and the membrane fouling characteristics of the coupled system were explored.The results showed that in villages with or without PPCPs,the growth rate of membrane fouling was faster under low C/N ratio（2.5）[no PPCPs:0.087 k Pa/d,add PPCPs:0.900 k Pa/d]than that under medium and high C/N ratios（4,6 and 9）[no PPCPs:0.045-0.065 k Pa/d,add PPCPs:0.539-0.615 k Pa/d].The membrane fouling increased the fastest when the two PPCPs coexisted（1.021 k Pa/d）.Under high C/N ratio,the sludge particle size increases and the membrane fouling rate slows down.SMPc in the filter cake layer is another main cause of membrane fouling.The higher the SMPc is,the more serious the membrane fouling will be.PPCPs increase the concentration of SMPc,leading to the aggravation of membrane fouling. |
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