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Abstract A new enhancing nitrogen removal constructed wetland which there were aeration pipes at the bottom of nitrification chamber and carbon addition pipes in the denitrification chamber was built, and effects of artificial aeration, external carbon source and both of them on treatment performance of constructed wetlands were investigated, based on important limiting factors for nitrogen removal in constructed wetlands, i.e. dissolved oxygen and carbon concentrations. The results showed that artificial aeration obviously improved the removal efficiency of TSS, COD, TN, NH4+-N and TP in constructed wetlands, while there was significant accumulation of NO3--N in the effluent in summer. External carbon source significant improved the removal efficiency of TN and NO3-- N in constructed wetlands, while had negative effect on COD removal efficiency in winter. Moreover, the results showed that artificial aeration and external carbon source had a synergistic effect on TN and NO3--N removal, and an independent effect on NH4+-N and COD removal, while showed an antagonism effect on the removal of TP and TSS. When the low-carbon and high-nitrogen wastewater mainly contained ammonia, the average removal efficiency of TN was 87.3% in constructed wetland under artificial aeration and external carbon source, so the enhanced system is especially suitable for treatment of wastewater with low-carbon and high-nitrogen.
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Received: 29 April 2015
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