Performance and Economic Evaluation of a Semibatch Vertical-Flow Wetland for Onsite Residential Bathroom Graywater Treatment.
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The performance and economic feasibility of residential bathroom graywater treatment using a semibatch vertical-flow wetland was evaluated over an eight-month field study in a single-family home in Los Angeles, Calif.

Graywater treatment time of only 3 h produced an effluent with turbidity (~0.3 ntu) and 5-day biochemical oxygen demand (~3.1 mg/L) that met graywater reuse guidelines for nonpotable applications. After chlorine disinfection, total coliform count was below the mandated level of 2.2 most probable number per 100 mL for aboveground water reuse. Process modeling demonstrated that the treatment process followed first-order kinetics with optimal operation at a hydraulic retention time of 0.3 h. Treatment capacity of 2 m3/day was feasible with the present system, which had a modest footprint area of 0.68 m2. Economic analysis demonstrated a breakeven period of between two to six years depending on the daily treatment volume. Higher water costs favor graywater treatment, especially when power costs are modest or low.

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Publication Summary

  • Geosyntec Authors: Yu, Zita
  • All Authors: Yu, Zita L.T.; Rahardianto, Anditya; Stenstrom, Michael K.; Cohen, Yoram
  • Title: Journal - American Water Works Association
  • Event or Publication: Publication
  • Practice Areas: Waste Management, Water and Natural Resources, Water Management
  • Citation: Issue Date: July 2016 Volume / Number: 108, Number 7 Page(s): E392-E404
  • Date: 2016