title: Multi-stage constructed wetland systems for municipal wastewater treatment.
abstract: In the present paper the detailed design and performances of two municipal wastewater treatment plants, a four-stage constructed wetlands (CW) system located in the city of Dicomano (about 3,500 inhabitants) in Italy, and a three-stage CW system for the village of Chorfech (about 500 inhabitants) in Tunisia, are presented. The obtained results demonstrate that multi-stage CWs provide an excellent secondary treatment for wastewaters with variable operative conditions, reaching also an appropriate effluent quality for reuse. Dicomano CWs have shown good performances, on average 86% of removal for the Organic Load, 60% for Total Nitrogen (TN), 43% for Total Phosphorus (TP), 89% for Total Suspended Solids (TSS) and 76% for Ammonium (NH4(+)). Even the disinfection process has performed in a very satisfactory way, reaching up to 4-5 logs of reduction of the inlet pathogens concentration, with an Escherichia coli average concentration in the outlet often below 200 UFC/100 mL. The mean overall removal rates of the Chorfech CWs during the monitored period have been, respectively, equal to 97% for TSS and Biochemical Oxygen Demand (BOD5), 95% for Chemical Oxygen Demand (COD), 71% for TN and 82% for TP. The observed removal of E. coli by the CW system was in this case 2.5 log units.
authors.affiliation: IRIDRA, Via Alfonso La Marmora 51, 50121, Florence, Italy. masi@iridra.com
authors.forename: F
authors.initials: F
authors.lastname: Masi
authors.forename: S
authors.initials: S
authors.lastname: Caffaz
authors.forename: A
authors.initials: A
authors.lastname: Ghrabi
mesh_terms: D002947:Cities; D007558:Italy; D014416:Tunisia; D062065:Wastewater / Q000032:analysis; D014876:Water Pollution / Q000517:prevention & control; D018508:Water Purification; D053833:Wetlands
chemical_list: D062065:Wastewater