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İstanbul, Turkey

Ayaz S.C.,TUBITAK - Marmara Research Center | Aktas O.,TUBITAK - Marmara Research Center | Findik N.,TUBITAK - Marmara Research Center | Akca L.,ITU Civil Engineering Faculty
Desalination and Water Treatment | Year: 2012

This research project aimed to determine the technologically feasible and applicable wastewater treatment systems which will be constructed to solve environmental problems of small communities in Turkey. Pilot-scale treatment of a small community's wastewater was performed over a period of more than 2 y in order to show applicability of these systems. The present study involves removal of phosphorus in horizontal (HFCW) and vertical (VFCW) sub-surface flow constructed wetlands operated in series. 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. Wastewater was first introduced into the HFCW and then VFCW before being discharged. VFCW achieved up to 60-90% phosphorus removal whereas HFCW could remove only less than 20%. The effect of type of filling material on adsorption of phosphorus was investigated both in adsorption studies and in 1 m2 constructed wetlands filled with different materials. The results showed that iron slag was the most efficient material for phosphorus removal in constructed wetlands compared to gravel, marble stone and zeolite. © 2012 Desalination Publications. All rights reserved. Source


Ayaz S.C.,TUBITAK - Marmara Research Center | Findik N.,TUBITAK - Marmara Research Center | Akca L.,ITU Civil Engineering Faculty | Erdogan N.,TUBITAK - Marmara Research Center | Kinaci C.,ITU Civil Engineering Faculty
Water Science and Technology | Year: 2011

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. © IWA Publishing 2011. Source


Ayaz S.C.,TUBITAK - Marmara Research Center | Aktas O.,TUBITAK - Marmara Research Center | Findik N.,TUBITAK - Marmara Research Center | Akca L.,ITU Civil Engineering Faculty | Kinaci C.,ITU Civil Engineering Faculty
Ecological Engineering | Year: 2012

Pilot-scale treatment of a small community's domestic wastewater was performed over a period of more than 2 years. The study involves removal of nitrogen in serially operated horizontal (HFCW) and vertical (VFCW) sub-surface flow constructed wetlands. Anaerobically pretreated wastewater was first introduced into HFCW and then VFCW before being discharged. HFCW supported denitrification in addition to removal of organic matter whereas VFCW obtained nitrification. Effective parameters such as temperature and effluent recirculation rate were tested in the system. Lower effluent concentrations were obtained with a 100% recirculation ratio compared to nonrecirculation. On the other hand, nitrification was found to be significantly higher in summer compared to winter. The pilot-scale system achieved the project goals by obtaining 98% total Kjeldahl nitrogen (TKN) and 79% total nitrogen (TN) removal during operation with recirculation. The study points out a novelty that the discharge limits could be achieved for nitrogen by the application of recirculation in a hybrid constructed wetland. The study shows that a hybrid constructed wetland system with recirculation is an effective method to obtain low nitrogen concentrations in downstream of anaerobic pretreatment of domestic wastewaters of small communities, particularly in the warm climate of the Mediterranean Region. © 2012 Elsevier B.V.. Source

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