How the novel integration of electrolysis in tidal flow constructed wetlands intensifies nutrient removal and odor control.

Intensified nutrient removal and odor control in a novel electrolysis-integrated tidal flow constructed wetland were evaluated. The average removal efficiencies of COD and NH4(+)-N were above 85% and 80% in the two experimental wetlands at influent COD concentration of 300 mg/L and ammonium nitrogen concentration of 60 mg/L regardless of electrolysis integration. Effluent nitrate concentration decreased from 2.5mg/L to 0.5mg/L with the reduction in current intensity from 1.5 mA/cm(2) to 0.57 mA/cm(2). This result reveals the important role of current intensity in nitrogen transformation. Owing to the ferrous and ferric iron coagulant formed through the electro-dissolution of the iron anode, electrolysis integration not only exerted a positive effect on phosphorus removal but also effectively inhibited sulfide accumulation for odor control. Although electrolysis operation enhanced nutrient removal and promoted the emission of CH4, no significant difference was observed in the microbial communities and abundance of the two experimental wetlands.

[1]  H Brix,et al.  Phosphorus adsorption maximum of sands for use as media in subsurface flow constructed reed beds as measured by the Langmuir isotherm. , 2003, Water research.

[2]  R. Dong,et al.  Performance of two laboratory‐scale horizontal wetlands under varying influent loads treating artificial sewage , 2012 .

[3]  Rumana Afrin,et al.  Treatment of tannery wastewater in a pilot-scale hybrid constructed wetland system in Bangladesh. , 2012, Chemosphere.

[4]  Dongxiao Zhang,et al.  Evaluation of a lab-scale tidal flow constructed wetland performance: Oxygen transfer capacity, organic matter and ammonium removal , 2011 .

[5]  Robert H. Kadlec,et al.  Comparison of free water and horizontal subsurface treatment wetlands , 2009 .

[6]  Awwa,et al.  Standard Methods for the examination of water and wastewater , 1999 .

[7]  Kaiqin Xu,et al.  Investigating CH4 and N2O emissions from eco-engineering wastewater treatment processes using constructed wetland microcosms , 2007 .

[8]  M. Gómez,et al.  Influence of carbon source on nitrate removal of contaminated groundwater in a denitrifying submerged filter. , 2000, Journal of hazardous materials.

[9]  Y. Sakakibara,et al.  Electric prompting and control of denitrification. , 1993, Biotechnology and bioengineering.

[10]  Ülo Mander,et al.  Emission of N2O, N2, CH4, and CO2 from constructed wetlands for wastewater treatment and from riparian buffer zones , 2005 .

[11]  Norio Sugiura,et al.  Nitrate removal from groundwater by cooperating heterotrophic with autotrophic denitrification in a biofilm-electrode reactor. , 2011, Journal of hazardous materials.

[12]  Cheng Jie.  Novel Tidal-flow Constructed Wetland for Advanced Treatment of Domestic Sewage , 2012 .

[13]  Y. Sakakibara,et al.  Selective reduction of nitrate to nitrogen gas in a biofilm-electrode reactor , 1998 .

[14]  K. Y. Park,et al.  Hydrogenotrophic denitrification in a packed bed reactor: effects of hydrogen-to-water flow rate ratio. , 2010, Bioresource technology.

[15]  P. A Mays,et al.  Comparison of heavy metal accumulation in a natural wetland and constructed wetlands receiving acid mine drainage , 2001 .

[16]  Stephen J. Allen,et al.  Generating “Tide” in Pilot‐Scale Constructed Wetlands to Enhance Agricultural Wastewater Treatment , 2006 .

[17]  Robert H. Kadlec,et al.  Nitrogen processing gradients in subsurface-flow treatment wetlands—influence of wastewater characteristics , 2002 .

[18]  Raymond W. Lee,et al.  Oxidation of sulfide by Spartina alterniflora roots , 1999 .

[19]  C. Richardson,et al.  Mechanisms Controlling Phosphorus Retention Capacity in Freshwater Wetlands , 1985, Science.

[20]  Jan Vymazal,et al.  The use of hybrid constructed wetlands for wastewater treatment with special attention to nitrogen removal: a review of a recent development. , 2013, Water research.

[21]  Hans Brix,et al.  Functions of Macrophytes in Constructed Wetlands , 1994 .

[22]  Zhen Wang,et al.  Screening of phosphate-removing substrates for use in constructed wetlands treating swine wastewater , 2013 .

[23]  T. Binzer,et al.  Sulphide intrusion in eelgrass (Zostera marina L.) , 2004 .

[24]  S. Kantawanichkul,et al.  Wastewater Treatment by Tropical Plants in Vertical-flow Constructed Wetlands , 1999 .

[25]  Yaqian Zhao,et al.  Robust biological nitrogen removal by creating multiple tides in a single bed tidal flow constructed wetland. , 2014, The Science of the total environment.

[26]  Y. Comeau,et al.  Phosphorus removal by electric arc furnace steel slag and serpentinite. , 2006, Water research.

[27]  P. Cañizares,et al.  Study of the Electrocoagulation Process Using Aluminum and Iron Electrodes , 2007 .

[28]  A. E. Greenberg,et al.  Standard Methods for the Examination of Water and Wastewater seventh edition , 2013 .

[29]  R. Dong,et al.  Intensified nitrogen and phosphorus removal in a novel electrolysis-integrated tidal flow constructed wetland system. , 2014, Water research.

[30]  Shubiao Wu,et al.  Dynamics of nitrobenzene degradation and interactions with nitrogen transformations in laboratory-scale constructed wetlands. , 2013, Bioresource technology.