Hydraulic characterization and optimization of total nitrogen removal in an aerated vertical subsurface flow treatment wetland

Bioresour Technol. 2014 Jun:162:166-74. doi: 10.1016/j.biortech.2014.03.100. Epub 2014 Apr 3.

Abstract

In this study, a side-by-side comparison of two pilot-scale vertical subsurface flow constructed wetlands (6.2 m(2)×0.85 m, q(i)=95 L/m(2) d, τ(n)=3.5 d) handling primary treated domestic sewage was conducted. One system (VA-i) was set to intermittent aeration while the other was aerated continuously (VAp-c). Intermittent aeration was provided to VA-i in an 8 h on/4 h off pattern. The intermittently aerated wetland, VA-i, was observed to have 70% less nitrate nitrogen mass outflow than the continuously aerated wetland, VAp-c. Intermittent aeration was shown to increase treatment performance for TN while saving 33% of running energy cost for aeration. Parallel tracer experiments in the two wetlands showed hydraulic characteristics similar to one Continuously Stirred Tank Reactor (CSTR). Intermittent aeration did not significantly affect the hydraulic functioning of the system. Hydraulic efficiencies were 78% for VAp-c and 76% for VA-i.

Keywords: Aerated vertical flow constructed wetland; Fluorescein; Intermittent aeration; Nitrogen removal; Tracer study.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aerobiosis
  • Carbon / isolation & purification
  • Fluorescein / metabolism
  • Nitrogen / isolation & purification*
  • Organic Chemicals / isolation & purification
  • Oxygen / analysis
  • Oxygen Consumption
  • Rheology*
  • Statistics as Topic
  • Time Factors
  • Water / chemistry*
  • Water Purification / methods*
  • Wetlands*

Substances

  • Organic Chemicals
  • Water
  • Carbon
  • Nitrogen
  • Oxygen
  • Fluorescein