scholarly journals Nitrate removal in vertical flow constructed wetland planted with Vetiveria zizanioides: Effect of hydraulic load

2017 ◽  
Vol 99 ◽  
pp. 535-542 ◽  
Author(s):  
Adelaide Almeida ◽  
Fátima Carvalho ◽  
Maria J. Imaginário ◽  
Ivone Castanheira ◽  
Ana R. Prazeres ◽  
...  
Keyword(s):  
Constructed Wetland ◽  
Nitrate Removal ◽  
Vertical Flow ◽  
Vetiveria Zizanioides ◽  
Vertical Flow Constructed Wetland ◽  
Hydraulic Load

Effects of a saturated layer and recirculation on nitrogen treatment performances of a single stage Vertical Flow Constructed Wetland (VFCW)

2013 ◽  
Vol 68 (7) ◽  
pp. 1461-1467 ◽  
Author(s):  
S. Prigent ◽  
J. Paing ◽  
Y. Andres ◽  
F. Chazarenc
Keyword(s):  
Constructed Wetland ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Single Stage ◽  
Vertical Flow ◽  
Saturated Layer ◽  
Vertical Flow Constructed Wetland ◽  
Hydraulic Load ◽  
Nitrogen Concentrations ◽  
Kjeldahl Nitrogen

Upgrades to enhance nitrogen removal were tested in a 2 year old pilot vertical flow constructed wetland in spring and summer periods. The effects of a saturated layer and of recirculation were tested in particular. Two pilots (L = 2 m, W = 1.25 m, H = 1.2 m), filled with expanded schist (Mayennite®), were designed with hydraulic saturated layers of 20 and 40 cm at the bottom. Each pilot was fed with raw domestic wastewater under field conditions according to a hydraulic load of 15–38 cm d−1 (i.e. 158–401 g COD (chemical oxygen demand) m−2 d−1) and to recirculation rates ranging from 0% up to 150%. The initial load during the first 2 years of operation resulted in an incomplete mineralized accumulated sludge leading to total suspended solids (TSS), COD and biochemical oxygen demand (BOD5) release. A 40 cm hydraulic saturated layer enabled an increase of 5–10% total nitrogen (TN) removal compared to a 20 cm saturated layer. Recirculation allowed the dilution of raw wastewater and enhanced nitrification in a single stage. A design of 1.8 m² pe−1 (48 cm d−1, 191 g COD m−2 d−1) with a 40 cm saturated layer and 100% recirculation enabled the French standard D4 (35 mg TSS L−1, 125 mg COD L−1, 25 mg BOD5 L−1), nitrogen concentrations below 20 mg TKN (total Kjeldahl nitrogen) L−1 and 50 mg TN L−1, to be met.

Experiences from the full-scale implementation of a new two-stage vertical flow constructed wetland design

2013 ◽  
Vol 69 (2) ◽  
pp. 335-342 ◽  
Author(s):  
Guenter Langergraber ◽  
Alexander Pressl ◽  
Raimund Haberl
Keyword(s):  
Constructed Wetland ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Full Scale ◽  
Vertical Flow ◽  
Effluent Water ◽  
Two Stage ◽  
Vertical Flow Constructed Wetland ◽  
Hydraulic Load ◽  
Public Holidays

This paper describes the results of the first full-scale implementation of a two-stage vertical flow constructed wetland (CW) system developed to increase nitrogen removal. The full-scale system was constructed for the Bärenkogelhaus, which is located in Styria at the top of a mountain, 1,168 m above sea level. The Bärenkogelhaus has a restaurant with 70 seats, 16 rooms for overnight guests and is a popular site for day visits, especially during weekends and public holidays. The CW treatment system was designed for a hydraulic load of 2,500 L.d−1 with a specific surface area requirement of 2.7 m2 per person equivalent (PE). It was built in fall 2009 and started operation in April 2010 when the restaurant was re-opened. Samples were taken between July 2010 and June 2013 and were analysed in the laboratory of the Institute of Sanitary Engineering at BOKU University using standard methods. During 2010 the restaurant at Bärenkogelhaus was open 5 days a week whereas from 2011 the Bärenkogelhaus was open only on demand for events. This resulted in decreased organic loads of the system in the later period. In general, the measured effluent concentrations were low and the removal efficiencies high. During the whole period the ammonia nitrogen effluent concentration was below 1 mg/L even at effluent water temperatures below 3 °C. Investigations during high-load periods, i.e. events like weddings and festivals at weekends, with more than 100 visitors, showed a very robust treatment performance of the two-stage CW system. Effluent concentrations of chemical oxygen demand and NH4-N were not affected by these events with high hydraulic loads.

Nitrogen Removal Capacity in Horizon Subsurface Flow and Vertical Flow Constructed Wetland in Relation to Operational Mode

2011 ◽  
Vol 374-377 ◽  
pp. 118-121
Author(s):  
Tian Xie ◽  
Zong Lian She ◽  
En Shi ◽  
Lei Lei Li ◽  
Ying Jie Zhu
Keyword(s):  
Nitrogen Removal ◽  
Constructed Wetland ◽  
Removal Rate ◽  
Nitrate Removal ◽  
Subsurface Flow ◽  
Vertical Flow ◽  
Operational Mode ◽  
Removal Capacity ◽  
Vertical Flow Constructed Wetland ◽  
Operational Modes

Two laboratory scale constructed wetlands were designed as horizon subsurface flow constructed wetland (HFCW) and vertical flow constructed wetland (VFCW) and were utilized to study the treatment capacity to reduce nitrogen. According to different inflow concentration and height of water surface, HFCW was analyzed in two operational modes and VFCW in four operational modes. The semi-submerged VFCW had the best capacity to remove nitrogen and the total nitrogen removal rate reached to 92% and the removal rate of HFCW was 90%. Moreover, the un-submerged VFCW could reduce 93% ammonia but nitrate removal rate just was 9%. And the removal rates of NH4+-N, NO3--N and TN respectively were 85%, 80% and 81% in submerged VFCW.

Treatment of domestic wastewater by vertical flow constructed wetland planted with umbrella sedge and Vetiver grass

2013 ◽  
Vol 68 (6) ◽  
pp. 1345-1351 ◽  
Author(s):  
Suwasa Kantawanichkul ◽  
Somsiri Sattayapanich ◽  
Frank van Dien
Keyword(s):  
Removal Efficiency ◽  
Constructed Wetland ◽  
Plant Biomass ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Nitrogen Accumulation ◽  
Vertical Flow ◽  
Vetiver Grass ◽  
Vetiveria Zizanioides ◽  
Vertical Flow Constructed Wetland

The aim of this study was to investigate the efficiency of wastewater treatment by vertical flow constructed wetland systems under different hydraulic loading rates (HLR). The comparison of two types of plants, Cyperus alternifolius (Umbrella sedge) and Vetiveria zizanioides (Vetiver grass), was also conducted. In this study, six circular concrete tanks (diameter 0.8 m) were filled with fine sand and gravel to the depth of 1.23 m. Three tanks were planted with Umbrella sedge and the other three tanks were planted with Vetiver grass. Settled domestic wastewater from Chiang Mai University (chemical oxygen demand (COD), NH4+-N and suspended solids (SS) of 127.1, 27.4 and 29.5 mg/L on average, respectively) was intermittently applied for 45 min and rested for 3 h 15 min. The HLR of each tank was controlled at 20, 29 and 40 cm/d. It was found that the removal efficiency of the Umbrella sedge systems was higher than the Vetiver grass systems for every parameter, and the lowest HLR provided the maximum treatment efficiency. The removal efficiency of COD and nitrogen in terms of total Kjeldahl nitrogen (TKN) was 76 and 65% at 20 cm/d HLR for Umbrella sedge compared to only 67 and 56% for Vetiver grass. Nitrogen accumulation in plant biomass was also higher in Umbrella sedge than in Vetiver grass in every HLR. Umbrella sedge was thus proved to be a suitable constructed wetland plant in tropical climates.

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