scholarly journals Performance assessment and microbial diversity of two pilot scale multi-stage sub-surface flow constructed wetland systems

2016 ◽  
Vol 46 ◽  
pp. 38-46 ◽  
Author(s):  
A.O. Babatunde ◽  
Raul Miranda-CasoLuengo ◽  
Mehreen Imtiaz ◽  
Y.Q. Zhao ◽  
Wim G. Meijer
2021 ◽  
Vol 13 (22) ◽  
pp. 12456
Author(s):  
Tao Wang ◽  
Liping Xiao ◽  
Hongbin Lu ◽  
Shaoyong Lu ◽  
Xiaoliang Zhao ◽  
...  

The quality of micropolluted water is unstable and its substrate concentration fluctuates greatly. The goal is to predict the concentration effect on the treatment of nitrogen in a river with an actual low C/N ratio for the proposed full-scale Xiaoyi River estuary wetland, so that the wetland project can operate stably and perform the water purification function effectively in the long term. Two pilot-scale multistage constructed wetland–pond (MCWP) systems (S1 and S2, respectively) based on actual engineering with the same “front ecological oxidation ponds, two-stage horizontal subsurface flow constructed wetlands and surface flow constructed wetlands (SFCWs) as the core and postsubmerged plant ponds” as the planned process were constructed to investigate the effect of different influent permanganate indexes (CODMn) and total nitrogen (TN) contents on nitrogen removal from micropolluted river water with a fixed C/N ratio from summer to winter in the field. The results indicate that the TN removal rate in the S1 and S2 systems was significant (19.56% and 34.84%, respectively). During the process of treating this micropolluted water with a fixed C/N ratio, the influent of S2 with a higher CODMn concentration was conducive to the removal of TN. The TN removal rate in S2 was significantly affected by the daily highest temperature. There was significant nitrogen removal efficiency in the SFCWs. The C/N ratio was a major determinant influencing the nitrogen removal rate in the SFCWs. The organic matter release phenomenon in SFCWs with high-density planting played an essential role in alleviating the lack of carbon sources in the influent. This research strongly supports the rule that there is seasonal nitrogen removal in the MCWPs under different influent substrate concentrations, which is of guiding significance for practical engineering.


2011 ◽  
Vol 63 (10) ◽  
pp. 2360-2366 ◽  
Author(s):  
S. Ç. Ayaz ◽  
N. Findik ◽  
L. Akça ◽  
N. Erdoğan ◽  
C. Kınacı

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.


2020 ◽  
Author(s):  
Liping Xiao ◽  
Tao Wang ◽  
Hongbin Lu ◽  
Shaoyong Lu ◽  
Jiaxin Li ◽  
...  

Abstract Background Single-stage constructed wetlands (CWs) has a single ecological service function and is greatly affected by temperature, which are general in removal of total nitrogen. Multistage hybrid CWs were proven to capable of enhancing removal of nitrogen. Therefore, this study aimed to explore the variation in nitrogen removal in the combined CWs-pond process from summer to winter and the contribution of plant harvesting and the functions of bacteria to nitrogen removal. Methods A pilot-scale multistage constructed wetland-pond system (MCWP) with the process of "the pre-ecological oxidation pond + the two-level horizontal subsurface flow constructed wetland (HSCW) + the surface flow constructed wetland (SFCW) and the submerged plant pond (SPP)" was used to treat actual polluted river water in the field. During the 124 days of operation, the nitrogen concentrations in the units influent and effluent of the system were measured every two days, and the plant height in HSCWs and SFCW was measured once per month. When the system operated stably to the 72nd day, the substrates in the CWs were sampled to analyze the bacterial community structure and composition. Results The concentration of total nitrogen (TN) in the MCWP gradually decreased from 3.46 mg/L to 2.04 mg/L, and the average removal efficiency of TN was approximately 40.74%. The SPP performed the best among all units, and the TN removal efficiency was as high as 16.08%. The TN removal efficiency was significantly positively affected by the daily highest temperature. A formula between the total TN removal efficiency and the highest temperature was obtained by nonlinear fitting. The TN removal load rate in the HSCWs was 2.7–3.7 times that of the SFCW. Furthermore, the TN transformed by Iris pseudacorus L. accounted for 54.53% in the SFCW. Conclusion We found that the significant positive correlation between the daily highest temperature and the total TN removal rate a field MCWP system. The SFCW, as an advanced treatment unit, increased the proportion of nitrogen removed by plant harvesting. The bacteria completed the nitrogen cycle in the SFCW, which had high-density planting, through a variety of nitrogen removal pathways.


1994 ◽  
Vol 29 (4) ◽  
pp. 55-66 ◽  
Author(s):  
D. P. Sapkota ◽  
H. J. Bavor

Experiments were carried out in a horizontal gravel media filter (GMF) with media size ranging from 5-40 mm. Such gravel-based, sub-surface flow units have been used in both planted and unplanted formats in a range of constructed wetland systems. This GMF was subjected to various hydraulic application rates ranging from 1 m3/(m2.d) to 36 m3/(m2.d) over a twc-year period. The range of suspended solids (SS) concentration was 2-36 mg/l and that of turbidity (NTU) was 3-44 during the experimental period. The average removal of suspended solids varied from 30-86%. It was observed that SS was reduced by a maximum of 86% at an application rate of 13m3/(m2.d), within the above noted SS range. An additional laboratory scale experiment was carried out with artificially grown algae in a vertical perspex tube of 190 mm inner diameter (I.D.) in upward flow condition. Results from the laboratory scale and pilot scale experiments are presented and discussed. The study demonstrates that a constructed wetland format with a subsurface flow and horizontal gravel media component could be used as an alternative method for reducing suspended solids from maturation pond effluent


2021 ◽  
Vol 43 ◽  
pp. 102214
Author(s):  
Osama Abrahiem AL Falahi ◽  
Siti Rozaimah Sheikh Abdullah ◽  
Hassimi Abu Hasan ◽  
Ahmad Razi Othman ◽  
Hind Mufeed Ewadh ◽  
...  

2007 ◽  
Vol 55 (7) ◽  
pp. 155-161 ◽  
Author(s):  
L.L. Behrends ◽  
E. Bailey ◽  
P. Jansen ◽  
L. Houke ◽  
S. Smith

Several different types of constructed wetland systems are being used as decentralized treatment systems including surface-flow, subsurface-flow, vertical-flow, and hybrid systems. Archetypical wetland systems have design strengths and weaknesses, and therefore it should be possible to design combined (integrated) systems to optimize a number of important treatment processes. This study provides comparative efficacy data for two integrated wetland treatment systems (IWTS) designed to enhance treatment of medium strength wastewater generated from a pilot-scale intensive fish farm. Results from the twenty eight months study included consistently high removal of COD (84%+) and ammonia nitrogen (93%) in both systems. Initially, phosphorus removal was also high (>90%) in both systems, but removal efficacy declined significantly over time. Nitrate removal was significantly better in the system that provided sequential aerobic and anoxic environments. Short hydraulic retention times coupled with sustained removal of COD and ammonia indicate that the ReCip components could be a least-cost wastewater treatment technology in the decentralized market sector.


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