title: Effect of recirculation on organic matter removal in a hybrid constructed wetland system.
abstract: This research project aimed to determine the technologically feasible and applicable wastewater treatment systems which will be constructed to solve environmental problems caused by small communities in Turkey. Pilot-scale treatment of a small community's wastewater was performed over a period of more than 2 years in order to show applicability of these systems. The present study involves removal of organic matter and suspended solids in serially operated horizontal (HFCW) and vertical (VFCW) sub-surface flow constructed wetlands. The pilot-scale wetland was constructed downstream of anaerobic reactors at the campus of TUBITAK-MRC. Anaerobically pretreated wastewater was introduced into this hybrid two-stage sub-surface flow wetland system (TSCW). Wastewater was first introduced into the horizontal sub-surface flow system and then the vertical flow system before being discharged. Recirculation of the effluent was tested in the system. When the recirculation ratio was 100%, average removal efficiencies for TSCW were 91 +/- 4% for COD, 83 +/- 10% for BOD and 96 +/- 3% for suspended solids with average effluent concentrations of 9 +/- 5 mg/L COD, 6 +/- 3 mg/L BOD and 1 mg/L for suspended solids. Comparing non-recirculation and recirculation periods, the lowest effluent concentrations were obtained with a 100% recirculation ratio. The effluent concentrations met the Turkish regulations for discharge limits of COD, BOD and TSS in each case. The study showed that a hybrid constructed wetland system with recirculation is a very effective method of obtaining very low effluent organic matter and suspended solids concentrations downstream of anaerobic pretreatment of domestic wastewaters in small communities.
authors: TUBITAK-MRC (Marmara Research Center), 41470, Pbox: 21, Gebze, Kocaeli, Turkiye. Selma.Ayaz@mam.gov.tr
authors: S C
authors: SC
authors: Ayaz
authors: N
authors: N
authors: Findik
authors: L
authors: L
authors: Akça
authors: N
authors: N
authors: Erdoğan
authors: C
authors: C
authors: Kinaci
mesh_terms: D009930:Organic Chemicals / Q000302:isolation & purification*; D018505:Waste Management; D014872:Water Movements; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D053833:Wetlands
chemical_list: D009930:Organic Chemicals; D014874:Water Pollutants, Chemical