Effect of cathode layer configuration on operational performance of a constructed wetland based on electrode-dependent ammonium oxidation
A cathode layer was installed in a constructed wetland(CW)based on electrode-dependent ammonium oxidation,so as to achieve the occurrence of cathodic autotrophic denitrification in the layer,and it was conducted to explore the effect of cathode layer configuration on operational performance of the device,simultaneously,the microbial characteristics and the associated nitrogen transformation mechanisms in the system were also analyzed and elucidated.The results showed that,cathode layer configuration could significantly affect quantities of the critical functional microorganisms in the cathode layer,and then distinction in the intensity of cathodic autotrophic denitrification occurred in the region,leading to differences of nitrogen removal and electricity generation among the three devices.Regarding to the CW based on electrode-dependent ammonium oxidation,as bio-cathode was installed in its cathode layer filled with broken bricks,abundances and activities of the functional microbes(especially Geobacter,Thauera,Thiobacillus,Pseudomonas,and Hydrogenophaga)involved in cathodic NOx--N reduction increased since the improved cathode layer had lager specific surface area,higher total content of water-soluble salt,and Fe content.Correspondingly,multi-path coupled nitrogen removal system based on"electrode dependent ammonium oxidation-cathodic autotrophic denitrification"was established in the equipment owing to the largely enhancement of the cathodic autotrophic denitrification.Under the circumstances,ideal operational performance of the CW could be achieved,its COD,TP,TN and NH4+-N removal rates could respectively reached up to(88.79±2.58)％,(98.19±0.72)％,(91.34±3.58)％,and(96.78±2.90)％during the stable operation phase.Moreover,the output voltage and the maximum power density of the device was(787.99±89.43)mV and 214.41 W/m3,respectively.This study should be conducive to research,development,and design of the new type of constructed wetland with enhancement of nitrogen removal.
万方数据
维普
