Anammox process in Thai wastewater treatment systems (Constructed wetland)

Abstract

© 2020, Thai Society of Higher Eduation Institutes on Environment. All rights reserved. Microbial characterization were identified uncultured Candidatus Accumulibacteria phosphatis clade and Candidatus Nitrotoga sp. in sediment and root plant biofilm of full scale of constructed wetland site at Laem Phak Bia (located at Phetchaburi Province, Thailand) but not full scale of constructed wetland to treat only storm water at Fukuoka, Japan. This result potentially suggests that constructed wetlands may be able to remove nitrogen under anaerobic conditions without significant organic carbon source. In a pilot-scale constructed wetland, three wetlands cells were inoculated with enriched suspended anammox cultures and fed synthetic wastewater with 50, 70, and 90 mg N/L of both NH4+-N and NO2--N (1:1.32) at controlled retention time (3 and 5 days). After 5 months days of operation, at different HRT (3 and 5 days) NH4+-N removal efficiencies ranged from 92.3% and 95.5%, respectively and NO2--N removal efficiencies from 96.5% to 99.7%, respectively. In the control, NH4+-N average removal efficiencies were 82.5% and 82.4%, respectively and NO2--N average removal efficiencies were 70.4% and 72.6%, respectively. These results suggest that anammox bacteria can grow and establish naturally in horizontal subsurface-flow constructed wetlands and that such systems may be effective for the treatment of wastewater with low BOD but high nitrogen for water reclamation.