Effect of recirculation on organic matter removal in a hybrid constructed wetland system

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.

2013 ◽  
Vol 68 (10) ◽  
pp. 2271-2278 ◽  
Author(s):  
Israa Abdulwahab Al-Baldawi ◽  
Siti Rozaimah Sheikh Abdullah ◽  
Nurina Anuar ◽  
Fatihah Suja ◽  
Mushrifah Idris

One of the appropriate development technology options for the treatment of wastewater contaminated with diesel is constructed wetlands (CWs). Throughout 72 days of exposure, sampling was carried out for monitoring of physical parameters, plant growth and the efficiency of total petroleum hydrocarbon (TPH) removal, as an indication for diesel contamination, to assess the pilot-scale performance. Four pilot CWs with a horizontal sub-surface flow system were applied using the bulrush of Scirpus grossus. The CWs were loaded with different diesel concentrations of 0, 0.1, 0.2 and 0.25% (Vdiesel/Vwater). The TPH removal efficiencies were 82, 71, and 67% at the end of 72 days for diesel concentrations of 0.1, 0.2, and 0.25% respectively. In addition, the high removal efficiency of total suspended solids and chemical oxygen demand (COD) were 100 and 75.4% respectively, for a diesel concentration of 0.1%. It was concluded that S. grossus is a potential plant that can be used in a well-operated CW for restoring 0.1% diesel-contaminated water.


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


2020 ◽  
Vol 7 (2) ◽  
pp. 70-74
Author(s):  
Fidelis C. Nkeshita ◽  
A. A. Adekunle ◽  
R. B. Onaneye ◽  
O. Yusuf

Wastewater from abattoir sources in urban areas can adversely affect the environment and cause health problems. This research investigated the ability of a bamboo constructed wetland system (BCWS) using Bambusa vulgaris, to treat wastewater from abattoir by removing nutrients and organics. This study adopted pilot scale reactors with bed dimension of 1 m length x 1 m width x 1 m depth to simulate a horizontal sub-surface flow constructed wetland and planted with six strands of bamboo plants. Parameters analyzed include the nutrients (in the form of phosphate and nitrate) and the organics (in the form of Chemical oxygen demand, COD and Biochemical oxygen demand, BOD). The effluent analysis that were carried out within a 28-day retention period showed that there was a very good decrease in the nutrient pollutant parameters; phosphate (99.6 %), nitrate (98.5 %). The organics showed a lesser performance with a 39.3 % removal efficiency for COD and 49.9 % removal efficiency for BOD. Bamboo can be used in a BCWS for low cost green technology in urban areas and can be improved upon by increasing the number of bamboo shoot in order to have a larger root system.


2015 ◽  
Vol 16 (1) ◽  
pp. 69-82 ◽  
Author(s):  
Anita Jakubaszek ◽  
Zofia Sadecka

Abstract This paper presents the results of the research work related to the removal efficiency from wastewater organic pollutants and suspended solids at HSSF (horizontal subsurface flow) constructed wetland. The average effectiveness defined as loss of value COD in wastewater has reached 77%, for BOD5 - 80% and TOC - 82%. The effect of seasonal temperature changes and the period of plant vegetation and rest on the effectiveness of wastewater treatment were also analyzed. The results of the presented research showed a decrease in the efficiency of removing organic pollutants from wastewater and suspended solids in the autumn and winter. During the vegetation the object in Małyszyn has been characterized by the effectiveness of wastewater treatment at the level of 78% for COD, 82% for BOD5, and in the non-vegetation period the effectiveness has decreased up to 75% for COD and 74% for BOD5. During the plants growth the total suspension was removed in 88%, whereas during the plants rest efficiency of removing lowered to 69%.


2018 ◽  
Vol 13 (4) ◽  
pp. 764-770 ◽  
Author(s):  
T. M. Adyel ◽  
M. R. Hipsey ◽  
C. Oldham

Abstract This study assessed the significance of a multi-functional and multi-compartment constructed wetland (CW) implemented to restore a degraded urban waterway in Western Australia. The wetland was initially constructed as a surface flow system, then modified through the incorporation of the additional laterite-based subsurface flow system, with the potential for operation of a recirculation scheme and groundwater top-up during low water flows in summer. The CW performance was assessed by comparing nitrogen (N) and phosphorus (P) attenuation during base flow, high flow and episodic storm flow conditions. The performance varied from approximately 41% total nitrogen (TN) and 66% total phosphorus (TP) loads reduction during storm events, increasing up to 62% TN and 99% TP during low flow and summer recirculation periods. In overall, the CW attenuated about 45% TN and 65% TP loads from being delivered to the downstream sensitive river between 2009 and 2015. The CW design proved to be not only highly effective at reducing nutrient loads, but also improved the ecological services of the urban waterway by providing a diverse area for habitat and recreational activities.


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