Performance evaluation of wastewater treatment using horizontal subsurface flow constructed wetlands optimized by micro-aeration and substrate selection

2015 ◽  
Vol 71 (9) ◽  
pp. 1317-1324 ◽  
Author(s):  
Fei Zhong ◽  
Juan Wu ◽  
Yanran Dai ◽  
Dongfang Xiang ◽  
Shuiping Cheng ◽  
...  
Keyword(s):  
Constructed Wetlands ◽  
Sewage Treatment ◽  
Subsurface Flow ◽  
Oxygen Demand ◽  
Ammonium Nitrogen ◽  
Domestic Sewage ◽  
Substrate Selection ◽  
N Removal ◽  
Horizontal Subsurface Flow ◽  
The Individual

The effects of micro-aeration and substrate selection on domestic sewage treatment performance were explored using three pairs (with or without micro-aeration) of horizontal subsurface flow (HSSF) constructed wetlands (CWs) filled with zeolite, ceramsite or quartz granules. The individual and combined effects of micro-aeration and substrate selection on the purification performance of the experimental-scale HSSF CWs were evaluated. The results showed that micro-aeration significantly increased the treatment efficiencies for chemical oxygen demand, total nitrogen, total phosphorus (TP), ortho-phosphate (PO43−-P) and ammonium nitrogen (NH4+-N) using HSSF CWs, while the substrate selection significantly affected the TP, PO43−-P and NH4+-N removal efficiencies (p < 0.05). A two-way analysis of variance (ANOVA) indicated that there was a significant interaction term (i.e. micro-aeration × substrate selection) for NH4+-N removal (p < 0.05). Among the three substrates, ceramsite was the best substrate for the treatment of domestic sewage using HSSF CWs. Therefore, the results of this study suggest that a ceramsite-filled HSSF CW with micro-aeration could be the optimal configuration for decentralized domestic sewage treatment.

Mass transfer approach and the designing of horizontal subsurface flow constructed wetland systems treating waste stabilisation pond effluent

2018 ◽  
Vol 78 (12) ◽  
pp. 2639-2646 ◽  
Author(s):  
Anita M. Rugaika ◽  
Damian Kajunguri ◽  
Rob Van Deun ◽  
Bart Van der Bruggen ◽  
Karoli N. Njau
Keyword(s):  
Mass Transfer ◽  
Constructed Wetlands ◽  
Rate Constants ◽  
Removal Rate ◽  
Subsurface Flow ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Organic Load ◽  
Mass Transfer Effect ◽  
Horizontal Subsurface Flow

Abstract Pilot-scale constructed wetlands (CWs) that allowed wastewater to flow with high interstitial velocities in a controlled environment were used to evaluate the possibility of using mass transfer approach to design horizontal subsurface flow constructed wetlands (HSSF-CWs) treating waste stabilisation ponds (WSPs) effluent. Since CW design considers temperature which is irrelevant in tropics, mass transfer approach could improve the design. HSSF-CWs were operated in batch recycle mode as continuous stirred tank reactors (CSTR) at different interstitial velocities. The overall removal rate constants of chemical oxygen demand (COD) at various interstitial velocities were evaluated in mesocosms that received pretreated domestic wastewater. The mean overall removal rate constants were 0.43, 0.69, 0.74 and 0.73 d−1 corresponding to interstitial velocities of 15.43, 36, 56.57 and 72 md−1, respectively. Results showed that the interstitial velocities up to 36 md−1 represented a range where mass transfer effect was significant and, above it, insignificant to the COD removal process. Since WSPs effluent has high flow rates and low organic load, it is possible to induce high interstitial velocities in a HSSF-CW treating this effluent, without clogging and overflow. The performance of these HSSF for tertiary treatment in tropical areas could be improved by considering flow velocity when designing.

scholarly journals Efficiency of horizontal subsurface flow constructed wetlands cultivated with grasses of different root systems

2020 ◽  
Vol 20 (8) ◽  
pp. 3318-3329
Author(s):  
Fernanda Lamede Ferreira de Jesus ◽  
Antonio Teixeira de Matos ◽  
Mateus Pimentel de Matos
Keyword(s):  
Constructed Wetlands ◽  
Subsurface Flow ◽  
Oxygen Demand ◽  
Root Systems ◽  
Sodium Concentration ◽  
Pollutant Removal ◽  
Organic Loading Rate ◽  
Vetiver Grass ◽  
Horizontal Subsurface Flow ◽  
Subsurface Flow Constructed Wetlands

Abstract The objective of this study was to evaluate the influence of stoloniferous and fasciculated root systems, of Tifton 85 and vetiver grass respectively, on pollutant removal for primary treatment of sewage in horizontal subsurface flow constructed wetlands (HSSF-CWs). For this, three HSSF-CWs measuring 4 m × 1 m × 0.25 m, filling with gneiss gravel # 0 (D60 of 7.0 mm and 48.4% porosity) as substrate, were used. One unit was cultivated with Tifton 85 grass (HSSFT-CW), one with vetiver grass (HSSFV-CW) and one remained uncultivated (HSSFC-CW) as a control. Sewage was applied at a flow rate of 0.53–0.80 m3 d−1, corresponding to an organic loading rate of approximately 350 kg ha−1 d−1 (biochemical oxygen demand – BOD), which resulted in a hydraulic retention time of 0.6–0.9 day. The HSSFV-CW was more efficient than the HSSFC-CW in removing dissolved solids (measured as electrical conductivity) and reducing the total suspended solids (TSS), BOD5, turbidity and sodium concentration, while the HSSFT-CW was not superior in any way. The results indicate that cultivation of vetiver grass provided increased efficiency for removing pollutants from sewage when compared with Tifton 85-grass, in the HSSF-CW.

The Effect of Temperature and Loading Rate on the Ammonia Nitrogen Removal in Horizontal Subsurface-Flow Constructed Wetlands with Different Vegetation and Substrate

2014 ◽  
Vol 522-524 ◽  
pp. 609-614
Author(s):  
Xue Cen Yu ◽  
Ming Xiao Zhang ◽  
Yue Wen ◽  
Qi Zhou
Keyword(s):  
Constructed Wetlands ◽  
Subsurface Flow ◽  
Ammonia Nitrogen ◽  
Effect Of Temperature ◽  
Polluted Water ◽  
Removal Rates ◽  
Gravel Bed ◽  
N Removal ◽  
Horizontal Subsurface Flow ◽  
Subsurface Flow Constructed Wetlands

The removal of ammonia nitrogen from the polluted water was investigated in three different types of horizontal subsurface flow constructed wetlands, reed (Phragmites australis)/gravel bed (W1), hybrid vegetation {reed, cattail (Typha latifolia), bulrush (Scirpus validus)}/gravel bed (W2) and reed/hybrid substrates (gravel, zeolite, slag) bed (W3). At HRT of 28 d, NH3-N removal efficiencies of W1, W2 and W3 were-130%98%, -120%98% and 21%98% respectively throughout the whole year. The results showed that zeolite and slag contributed to higher NH3-N removal than gravel, especially in winter, and that cattail and bulrush did not show significant influences on NH3-N removal. The ranges of NH3-N removal rates were-2.332.14, -2.272.33 and 0.082.52 g·m-3·d-1 respectively under HRT of 2 d. NH3-N removal rates of W1 and W2 were much more affected by temperature than that of W3, which was due to the adsorption/desorption of zeolite.

Experimental study of a novel hybrid constructed wetland for water reuse and its application in Southern China

2011 ◽  
Vol 64 (11) ◽  
pp. 2177-2184 ◽  
Author(s):  
J. Zhai ◽  
H. W. Xiao ◽  
K. Kujawa-Roeleveld ◽  
Q. He ◽  
S. M. Kerstens
Keyword(s):  
Constructed Wetland ◽  
Water Reuse ◽  
Southern China ◽  
Sewage Treatment ◽  
Subsurface Flow ◽  
Circulatory System ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Municipal Sewage ◽  
Horizontal Subsurface Flow

A new type of hybrid constructed wetland (CW), consisting of both vertical-baffled flow wetland (VBFW) and horizontal subsurface flow wetland (HSFW), has been deployed in Southern China to naturally accelerate the removal of organic matter and nitrogen. The hybrid CW system is characterised by a combination of continuous baffled flow vertical wetland and ‘S’ pattern horizontal subsurface flow wetland with natural aeration ditches to increase the concentration of dissolved oxygen in the HSFW bed. An internal circulatory system from the HSFW effluent back to the VBFW may optionally be operated to enhance the biological denitrification effect. Cyperus alternifolius is the main macrophyte in the wetland bed. The performance of the hybrid CW was studied with a pilot-scale system and three full-scale systems for municipal sewage treatment in Southern China. The results suggest that this new hybrid CW can achieve removal efficiencies of chemical oxygen demand, suspended solids, ammonia nitrogen, total nitrogen, and total phosphorus of better than 83.6, 95.0, 71.7, 64.5 and 68.1% respectively, with a specific wetland bed area of 0.70–0.93 m2 PE−1. The mean effluent concentrations of these parameters would meet the regulatory discharge limits for wastewater treatment systems (GB18918, 2002) and reuse in the context of agricultural irrigation solutions in China.

scholarly journals Multistage Horizontal Subsurface Flow vs. Hybrid Constructed Wetlands for the Treatment of Raw Urban Wastewater

2020 ◽  
Vol 12 (12) ◽  
pp. 5102
Author(s):  
José Alberto Herrera-Melián ◽  
Mónica Mendoza-Aguiar ◽  
Rayco Guedes-Alonso ◽  
Pilar García-Jiménez ◽  
Marina Carrasco-Acosta ◽  
...  
Keyword(s):  
Constructed Wetlands ◽  
Subsurface Flow ◽  
Oxygen Demand ◽  
Pollutant Removal ◽  
Urban Wastewater ◽  
Total Coliforms ◽  
E Coli ◽  
Effect Of Water ◽  
Horizontal Subsurface Flow ◽  
Water Height

In this study, pilot-scale hybrid constructed wetlands (CWs) and multistage horizontal subsurface flow CWs (HF CWs) have been studied and compared for the treatment of raw urban wastewater. In the hybrid CWs, the first stage was a mulch-based horizontal subsurface flow CW and the second stage was a vertical subsurface flow CW (VF CW). The VF CWs were used to determine if sand could improve the performance of the hybrid CW with respect to the mulch. In the multistage HFs, mulch, gravel and sand were used as substrates. The effect of water height (HF10: 10 cm vs. HF40: 40 cm) and surface loading rate (SLR: 12 vs. 24 g Chemical Oxygen Demand (COD)/m2d) has been studied. The results show that the use of sand in the vertical flow stage of the hybrid CW did not improve the average performance. Additionally, the sand became clogged, while the mulch did not. The effect of water height on average pollutant removal was not determined but HF10 performed better regarding compliance with legal regulations. With a SLR of 12 g COD/m2d, removals of HF10 were: 79% for COD, 75% for NH4+-N, 53% for dissolved molybdate-reactive phosphate-P (DRP), 99% for turbidity and 99.998% for E. coli and total coliforms. When SLR was doubled, removals decreased for NH4+-N: 49%, DRP: −20%, E coli and total coliforms: 99.5–99.9%, but not for COD (85%) and turbidity (99%). Considering the obtained results and the simplicity of the construction and operation of HFs, HF10 would be the most suitable choice for the treatment of raw urban wastewater without clogging problems.

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