| With the increase of the global population,the situation of water resources in our country is becoming more and more severe.The reuse of reclaimed-water can not only solve the contradiction between the current shortage of water resources and the increasing water consumption for domestic production,but also protect and restore the role of the water eco-environment.Qualified effluent treated by Wastewater treatment plants(WWTPs)can be used as an important resource for water reuse.However,after the preliminary treatment of sewage by many domestic processes,the effluent still contains a certain concentration of NO3--N and TP,as well as PPCPs pollutants,of which the content of amoxicillin is in the first echelon.The long-term accumulation of these substances in the environment will poses a threat to human health,animal survival,and the ecological environment.Therefore,the exploration and development of new sewage treatment technology is significant in order to achieve the deep nitrogen and phosphorus removal of water bodies with low-C/N water such as WWTPS effluent and the remove the antibiotic that is hard to degrade.In the existing academic research,the three-dimension biofilm-electrode reactor(3DBER)is widely used for nitrogen and phosphorus removal.But,there are not many studies on the use of the 3DBER-S/Fe system for nitrogen and phosphorus removal and further removal of amoxicillin.In this study,by using the self-designed three-dimension biofilm-electrode reactor(3DBER),in which the three-dimension biofilm-electrode is coupled with sulfur autotrophic denitrification and iron autotrophic denitrification to form a 3DBER-S/Fe system,using simulative the outlet of the secondary sedimentation tank,and starting the reactor with the micro-current to study the performance of the system for nitrogen and phosphorus removal and analyze the mechanism of nitrogen and phosphorus removal.Experiments show that the removal rates of NO3--N,TN and TP after successful start-up reach 95%,86%and 81%.The accumulation of NO2--N and NH4+-N effluent was at about 1.61 mg/L and 1.79 mg/L.According to "Urban Miscellaneous Water Quality Standard" and "Landscape Environmental Water Quality Index",it can be directly used as urban miscellaneous water for toilet flushing,urban greening,etc.As well as environmental water for landscapes.After the reactor was started,we analyzed the influence of different HRT(4 h,6 h,8 h,9 h)on the system’s nitrogen and phosphorus removal effect.The results showed that when HRT=8 h,NO3--N,TN,and TP had the best removal effect,in which the removal rates are 96.76%,87.69%,and 82.83%in order.We study the effect of different current intensities(25 mA,50 mA,100 mA,200 mA,400 mA)on the removal of nitrogen effect of the 3DBER-S/Fe system and the result shows that the current intensity has no significant effect on the removal of nitrogen.The increase of the current intensity is beneficial to the removal of phosphorus by the 3DBER-S/Fe system,but the excessive current will also cause the loss of electrode material and increase the chromaticity of the water.In addition,when the current or HRT increases,the NO2--N concentration in the effluent decreases significantly;when the current or the HRT decreases,the NH4+-N concentration in the effluent decreases significantly.In research of the effect of the 3DBER-S/Fe system on the removal of amoxicillin and the effect of amoxicillin on the performance of the system for nitrogen and phosphorus removal,the results show that there was no significant effect when adding 1000 μg/L amoxicillin in the feed water on the system for the removal the NO3--N,for which the removal rate was 97.40%.But it led the effluent concentration of NO2--N and NH4+-N to increase from 0.98 mg/L and 2.05 mg/L to 1.26 mg/L and 2.50 mg/L respectively,which affects the TN removal.Although the removal rates of TN and TP decreased from 88.73%and 84.87%to 87.30%and 82.39%respectively,but they still maintain a high removal rate.At the same time,when the reactor was running stably,the removal rate of amoxicillin was 96.78%.To study the effect of HRT(4 h,6 h,8 h)on the removal of amoxicillin,the results indicate:when the HRT is 8 hours and 6 hours,the 3DBER-S/Fe system has a better removal effect on amoxicillin with an average removal rate of 98.40%and 98.15%;when the HRT is 4 hours,the removal rate drops to 93.90%and still maintains a high removal rate.After compared the effects of different current intensities(100 mA,300 mA,500 mA)on the removal effect of amoxicillin,it showed that the current intensity has no significant effect on the removal of amoxicillin.When the current increases from 100 mA to 300 mA,the removal rate of amoxicillin increased from 98.16%to 98.62%;when the current is 500 mA,the removal rate decreases to 97.85%instead. |
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