Treatment of rich ammonia nitrogen wastewater with polyvinyl alcohol immobilized nitrifier biofortified constructed wetlands

• PVA-immobilized nitrifier was used to improve NH4-N removal in CWs.
• Increase of PVA-immobilized pellets dosage accelerated nitrification.
• Immobilized reactor planted with Canna L. achieved optimal NH4-N removal.
• PVA-immobilized might be applied in NH4-N wastewater treatment.
• The removal of organics and nitrogen compounds were higher in planted reactors.

Polyvinyl alcohol (PVA) immobilized nitrifier was adopted to enhance the treatment of wastewater containing rich ammonia nitrogen (NH4-N) in constructed wetlands (CWs). NH4-N removal in immobilized nitrifier biofortified constructed wetlands (INB-CWs) was positively correlated with the dosage of PVA pellets. INB-CWs planted with Canna indica L. exhibited removal efficiencies of 46% NH4-N, 43% total nitrogen and 65% COD, which are significant higher than control. INB-CWs outperformed the unplanted and non-immobilized constructed wetland or nitrifier suspension system. The ideal reaction conditions for treating synthetic wastewater containing 200 mg L−1 NH4-N were obtained as follows: pH, 8.5; dissolved oxygen, 4.0 mg L−1; temperature, 30 °C and PVA pellets dosage, 60 g L−1. In addition, degradation of PVA pellets accelerated nitrification. Results indicated that the PVA immobilized nitrifier had great potential applications for treating wastewater containing rich ammonia nitrogen in CWs.

Polyvinyl alcohol (PVA) immobilized nitrifier was adopted to enhance the treatment of wastewater containing rich ammonia nitrogen (NH4-N) in constructed wetlands (CWs). Immobilized nitrifier biofortified constructed wetlands planted with Canna indica L. exhibited significant higher removal of NH4-N, total nitrogen and COD. Results indicated that the PVA immobilized nitrifier had great potential applications for treating wastewater containing rich ammonia nitrogen in CWs.Figure optionsDownload as PowerPoint slide