Enhancement of nutrient removal from eutrophic water by a plant-microorganisms combined system

Abstract

Two species of perennial grasses-Lolium perenne var. Top One (LPT) and Lolium perenne var. respect (LPR)-and a microbial consortium composed of two denitrifying polyphosphate-accumulating organisms (DPAOs)-strain Bacillus sp. MOE1 and Microbacterium sp. MOE2-were used to study the effect of plant-microorganisms interaction on removing nutrients from eutrophic water. The two perennial grasses could greatly remove the nutrients and pollutants; LPT could remove up to 40% of total nitrogen (TN) and 87% of TP in 20 days. Among the two species of perennial grasses, LPT is more efficient in removal of ammonium nitrogen (NH 4+-N), phosphorus, and COD Mn. Without combining with LPT and LPR, the immobilized DPAOs could remove more than 73% phosphorus, 32% total nitrogen, and 81% ammonium nitrogen. Removal efficiency of phosphorus, TN, and NH 4+-N enhanced after combining DPAOs with perennial grasses, especially with LPT. The combination of DPAOs and LPT may prove to be a promising approach in bioremediation of eutrophic water. In addition, the activities of urease, invertase, and alkaline phosphatases positively changed with the removal of nitrogen, chemical oxygen demand (COD), and phosphorus correspondingly. © 2011, Mary Ann Liebert, Inc.