Nutrient recovery from anaerobic digester liquid effluent using ornamental aquatic macrophytes

Anaerobic digestion (AD) which treat food waste is a waste-to-energy method that produces liquid effluent. This by-product, known as digestate, contains high nutrients that could be recovered using ornamental aquatic macrophytes in a constructed wetland system. This study investigates the capacity of nutrient recovery of Canna indica, Iris pseudocarus, and Typha latifolia from liquid digestate, together improving the quality of AD effluent. Constructed wetland with T. latifolia effectively removed TSS and COD to meet the wastewater quality standards (TSS = 71 mg/L, COD = 56.735 mg/L). C. indica removed up to 72% N as the highest N removal efficiency, and recovered most of N, even though it still needs longer detention time to meet the standard. I. pseudocarus removed up to 98% P yet the average TP level in the plant was slightly above T. latifolia. The result shows that nutrient recovery using constructed wetland improves the effluent quality within short operation period, meanwhile C. indica and I. pseudocarus as ornamental aquatic macrophytes also added the aesthetic value to the environment.