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981.
Nutrient concentration variations during Oenanthe javanica growth and decay
in the ecological floating bed system 总被引:1,自引:0,他引:1
The ecological floating bed system is a natural alternative to technical methods of wastewater treatment and involves complex
processes induced by plants or microorganisms in the wastewater. This study aimed to identify nutrient concentration variations during
Oenanthe javanica (Blume) DC growth and decay in the ecological floating bed system. Results showed that the third-order polynomial
equation was suitable to describe pollutant concentration changes, showing that the effect of O. javanica ecological floating bed system
on polluted water could be divided into the purification phase and decay phase. During the purification phase, nutrient concentrations
rapidly decreased because O. javanica influenced water microbial communities and water physical parameters (i.e., dissolved oxygen,
pH, and temperature), and had a direct uptake of nutrients. However, during the decay phase, nitrogen and phosphorus concentrations
in the plant tissues decreased, and these lost nutrients ultimately transferred to water and led to water quality deterioration. Results
also showed that the uptake and storage of O. javanica in nutrients were temporary and the plant served only as media of the nutrients
removed from the water. Under these circumstances, harvesting was an appropriate intervention to improve the treatment efficiency of
O. javanica ecological floating bed system. 相似文献
982.
Evaluation of the e ectiveness of horizontal subsurface flow constructed
wetlands for di erent media
Two media bed (gravel and Filtralite NR) were tested in a mesocosm to evaluate the removal of organic matter (as chemical oxygen
demand (COD)), ammonia (NH4-N), nitrite, nitrate and solid matter (as total suspended solids (TSS)) for a synthetic wastewater
(acetate-based) and a domestic wastewater. The use of Filtralite allowed average removal rates (6–16.8 g COD/(m2 day), 0.8–1.1
g NH4-N/(m2 day) and 3.1 g TSS/(m2 day)) and removal e ciencies (65%–93%, 57%–85% and 78% for COD, NH4-N and TSS,
respectively), higher than that observed in the experiments with gravel. The applied loads of COD, ammonia, nitrate and TSS seem
to influence the respective removal rates but only for the treatment of domestic wastewater with higher correlation coe cients for
Filtralite. Regardless the type of media bed and the type of wastewater, nitrate was completely removed for nitrogen loading rates up to
1.3 g NO3-N/(m2 day). There was no evidence of the influence of nitrate loads on the removal of organic matter. 相似文献
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Zhigang LIU Shaomin ZHU Yansheng LI 《Frontiers of Environmental Science & Engineering》2012,6(1):45-50
A novel method for the regeneration of cation exchange resins by aluminum (Al) salts was investigated in order to improve the regeneration efficiency of resins and reduce the dosage of regenerant. The influences of Al3+ concentration and the pH of regeneration solution on resin transformation had been studied. The desalination experiments were carried out to evaluate the characteristics of the Al form resins. Experimental results showed that the regeneration rate of resins was strictly dependent on Al3+ concentration and the pH of the solution. Compared to the conventional regeneration method, the Al form mixed bed exhibited the same desalination capability as the H form mixed bed (MB), and the total organic carbon (TOC) removal was up to 90%, clearly higher than that of the H form. Al salt solution could be utilized repeatedly to regenerate Al form resins. 相似文献