Authors: YongJun Zhao Cheng Yan YinLiang Li JiHua Li Mo Yang Er Nie Zheng Zheng XingZhang Luo
Publish Date: 2012/04/15
Volume: 19, Issue: 9, Pages: 4049-4059
Abstract
The effects of the combination of filters earthworms plants as well as the combination of earthworms and plants on SDS nutrient removal efficiency were separately investigated to select the optimum system for treating SDS The results of the current study could be used to determine how treatment performance responds to different C/N ratios and to explain and predict the performance of an operating EE systemEE systems with earthworms and plants EP groups consistently performed better than the other types of systems CK E and P that is without earthworms and without plants with earthworms and without plants and without earthworms and with plants respectively under all C/N ratios The highest removal efficiencies of chemical oxygen demand total nitrogen total phosphorus and total organic carbon were achieved under C/N ratios of 61 61 61 and 91 respectively The optimum nutrient removal efficiency was achieved at C/N = 6 and the contribution order for nutrient removal was EP P E CKInfluent C/N ratios the time of year and the synergetic effects of earthworm behavior and microorganisms significantly affected nutrient removal efficiencies Considering the removal of all nutrients EE systems with plants and earthworms achieved optimum removal effects in July when the influent C/N ratio was controlled at 6 Appropriate control of carbon and nitrogen source concentrations permitted the achievement of optimal nutrient removal effectsWe thank colleagues and students from Fudan University for maintaining the EE systems during the study period We are very grateful to Naomi Cappuccino Department of Biology Carleton University Canada for comments on the draft and grammar of the manuscript This study was financially supported by the National Water Special Project of China no 2008ZX0710100104 and National Science Funds of China grant nos 51102136/E021301
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