Full-scale hybrid constructed wetlands monitoring for decentralized tertiary treatment of municipal wastewater

Abstract

This paper explores the feasibility and efficiency of a full-scale hybrid constructed wetland as a decentralized tertiary treatment facility to improve the quality of municipal secondary wastewater for reuse. The treatment wetland consists of a horizontal subsurface flow system (HSFCW) combined with a maturation pond (MP), with a treatment capability of 520 m3/d and operational process since November 2017. The monitoring of water quality was carried out during the first 3 years of operation. The removal efficiencies achieved by the multi-stage system (HSFCW-MP) were TSS, 47.31± 30.90%; BOD5, 45.24± 36.33%; COD, 37.52± 23.01%; TKN, 56.53± 15.70%; and TP, 69.09± 32.78%. The removal of fecal bacteria was 1.13 and 0.59 log units for FC and FS, respectively. Overall, HSFCW-MP achieved satisfactory removal rates and provided high-quality water from HSFCW and (HSFCW-) MP effluents that fit well with agricultural needs. Wide application of this promising approach for wastewater treatment and reuse in Tunisia and in water-scarce areas, through further basic improvements, is strongly recommended as described within this paper.