Effects of Connection Mode and Hydraulic Retention Time on Wastewater Pollutants Removal in Constructed Wetland Microcosms

2014 ◽  
Vol 43 (12) ◽  
pp. 1574-1581 ◽  
Author(s):  
Li-Jun Ren ◽  
Li-Li Xu ◽  
Yu-Yuan Zhang ◽  
Wei Pan ◽  
Sheng-Lai Yin ◽  
...  
Author(s):  
Isabela Pires da Silva ◽  
Gabriela Barbosa da Costa ◽  
João Gabriel Thomaz Queluz ◽  
Marcelo Loureiro Garcia

   This study evaluated the effect of hydraulic retention time on chemical oxygen demand (COD) and total nitrogen (TN) removal in an intermittently aerated constructed wetlands. Two horizontal subsurface-flow constructed wetlands were used: one without aeration and the other aerated intermittently (1 hour with aeration/7 hours without aeration). Both systems were evaluated treating domestic wastewater produced synthetically. The flow rate into the two CWs was 8.6 L day-1 having a hydraulic retention time of 3 days. The results show that the intermittently aerated constructed wetland were highly efficient in removing COD (98.25%), TN (83.60%) and total phosphorus (78.10%), while the non-aerated constructed wetland showed lower efficiencies in the removal of COD (93.89%), TN (48.60%) and total phosphorus (58.66). These results indicate, therefore, that intermittent aeration allows the simultaneous occurrence of nitrification and denitrification processes, improving the removal of TN in horizontal subsurface-flow constructed wetlands. In addition, the use of intermittent aeration also improves the performance of constructed wetlands in removing COD and total phosphorus.


2014 ◽  
Vol 1073-1076 ◽  
pp. 799-803
Author(s):  
Yu Qian Cui ◽  
Wen Xia Xie ◽  
Yue Li

In order to solve practical problems of rural sewage treatment, constructed wetland waste water treatment system is chose to simulate, analyze and evaluate in laboratory. Sand and gravel, granular activated carbons were used as the filter media in the constructed wetland. Experimental results show that the removal rate of filter for the water treatment increases with the rise of the hydraulic retention time and the rise of the temperature. It can be satisfied with the treatment effect at an ambient temperature of 15°C, maintained for 4 days or more hydraulic retention time.


2011 ◽  
Vol 71-78 ◽  
pp. 2852-2855
Author(s):  
Kun Shi ◽  
Ming Zou

The microcosm tests were done to estimated the HRT (Hydraulic Retention Time) and removal efficiency of reflowing treatment of the landfill leachate collected from Dalian Maoyingzi Municipal Solid Waste Landfill, which contained high levels of COD (Chemical Oxygen Demand, 38400 mg/L) and SS (Suspended Solids, 650 mg/L) by the reed constructed wetland located in the south area of Dalian Jiaotong University. The results showed that: (1) The HRT in nature soil cuboids were significant shorter than those in sieved soil cuboids (P<0.01); (2) The removal efficiency among the output water with the trend as follows: Preferential flow (53.9%)<Percolating water (59.2%)<Reflowing water (63.3%); (3) The COD and SS were decreased from 38400 and 650 mg/L to 14080 and 213 mg/L by the way of reflowing with the HSL (Hydraulic Surface Loading) of 0.16 m3/(m2·d) by reflowing (Removal efficiency: COD: 63.3%; SS: 67.3%).


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