Year-long exploratory assessment of a horizontal subsurface-flow constructed wetland containing locally sourced zeolite and planted with Cyperus alternifolius for greywater treatment in Jordan

Abstract

Context In arid environments such as Jordan, greywater treatment and recycling should be decentralized for better water resource management.Objective This study tests a lab-scale Horizontal Flow Constructed Wetland (HFCW) using locally supplied natural zeolite (Aritayn region) as a substrate and Cyperus alternifolius (Umbrella Sedge) as a phytoremediator.Methodology Four parallel reactors (M1–M4) were used in a one-year mesocosm experiment to compare zeolite substrate and vegetation treatment effects. Effluent quality was tested for compliance with Jordanian water reuse requirements (JS 893:2021) in an intermittent flow regime with a constant hydraulic retention time (HRT) of roughly 5 days.Results The vegetated system (M2) reduced COD and BOD5 more efficiently than the unplanted zeolite-only control (M4), with 75.2% and 65.5%, respectively. M2 disinfection eliminated 95.4% E. coli, meeting national raw vegetable irrigation criteria. Maintaining physicochemical stability, pH (6.71) and TDS (<378 mg/L) within permissible values prevented soil salinization. Greywater-fed Cyperus alternifolius grew to 84.4 cm but had high proline (1.567) and osmotic stress (54.9% RWC).Conclusion HFCWs containing local zeolite and Cyperus alternifolius represent a promising preliminary step for producing safe agricultural and landscape irrigation water efficiently and cheaply. However, remaining turbidity suggests a subsequent cleaning procedure for high-purity indoor reuse.