scholarly journals A tracer study in a vertical flow constructed wetland treating septage

2018 ◽  
Vol 15 (3) ◽  
pp. 345-353 ◽  
Author(s):  
Jason Jie Xiang Bui ◽  
Yee Yong Tan ◽  
Fu Ee Tang ◽  
Carrie Ho
Keyword(s):  
Constructed Wetlands ◽  
Constructed Wetland ◽  
Retention Time ◽  
Evaluation Method ◽  
Hydraulic Retention Time ◽  
Vertical Flow ◽  
Content Type ◽  
Hydraulic Loading ◽  
Hydraulic Behaviour ◽  
Vertical Flow Constructed Wetland

Purpose This study aims to investigate the hydraulic behaviour of a pilot-scale, two-staged, vertical flow constructed wetland (VFCW) for septage treatment, in terms of factors such as hydraulic retention time and hydraulic loading rate and its influence on the treatment dynamics. Because of intermittent feeding mode of VFCW systems and variation in its loading, its hydraulic behaviour is highly variable and need to be understood to optimize its treatment performance. Design/methodology/approach Tracer test were carried out using bromide ion with varying hydraulic loading rates (HLR) of 6.82 cm/d, 9.09 cm/d and 11.40 cm/d (i.e. equivalent to 75 L/d, 100L/d and 125 L/d). Tracer data is then analysed using the Residence Time Distribution (RTD) method. Findings RTD analysis showed that the increase in HLR increases the average hydraulic retention time (HRT). Subsequently, the increase in HLR results in a lower recovery of effluent, resulting in poor productivity in treatment. The study also showed that the removal of nitrogen and organic matter improved with increasing HRT. However, observations show no correlation between HRT and total solids removal. Originality/value A performance evaluation method (by tracer) is proposed to understand the hydraulics of flow in constructed wetlands, which has not been widely studied. Additionally, the dynamics of treatment in VFCWs treating septage may also be revealed by the tracer method. The study can be applied to any constructed wetlands designed for treatment of wastewater, septage or sludge.

scholarly journals Effect of hydraulic retention time on chemical oxygen demand and total nitrogen removal in intermittently aerated constructed wetlands

2020 ◽  
Vol 15 (3) ◽  
pp. 1 ◽  
Author(s):  
Isabela Pires da Silva ◽  
Gabriela Barbosa da Costa ◽  
João Gabriel Thomaz Queluz ◽  
Marcelo Loureiro Garcia
Keyword(s):  
Chemical Oxygen Demand ◽  
Constructed Wetlands ◽  
Total Nitrogen ◽  
Total Phosphorus ◽  
Constructed Wetland ◽  
Retention Time ◽  
Hydraulic Retention Time ◽  
Subsurface Flow ◽  
Oxygen Demand ◽  
Intermittent Aeration

   This study evaluated the effect of hydraulic retention time on chemical oxygen demand (COD) and total nitrogen (TN) removal in an intermittently aerated constructed wetlands. Two horizontal subsurface-flow constructed wetlands were used: one without aeration and the other aerated intermittently (1 hour with aeration/7 hours without aeration). Both systems were evaluated treating domestic wastewater produced synthetically. The flow rate into the two CWs was 8.6 L day-1 having a hydraulic retention time of 3 days. The results show that the intermittently aerated constructed wetland were highly efficient in removing COD (98.25%), TN (83.60%) and total phosphorus (78.10%), while the non-aerated constructed wetland showed lower efficiencies in the removal of COD (93.89%), TN (48.60%) and total phosphorus (58.66). These results indicate, therefore, that intermittent aeration allows the simultaneous occurrence of nitrification and denitrification processes, improving the removal of TN in horizontal subsurface-flow constructed wetlands. In addition, the use of intermittent aeration also improves the performance of constructed wetlands in removing COD and total phosphorus.

Correlation Studies of Dissolved Oxygen in the IVCW System Changes and Removal of Nitrogen

2012 ◽  
Vol 610-613 ◽  
pp. 417-421
Author(s):  
Ji Ku Zhang ◽  
Yue Lang ◽  
Ming Jie Li
Keyword(s):  
Dissolved Oxygen ◽  
Constructed Wetlands ◽  
Total Nitrogen ◽  
Constructed Wetland ◽  
Flow Direction ◽  
Vertical Flow ◽  
Correlation Studies ◽  
Vertical Flow Constructed Wetlands ◽  
Vertical Flow Constructed Wetland ◽  
System Changes

Experiment simulates the integrated vertical flow constructed wetland (IVCW) operation of the system, discusses the trend of Dissolved Oxygen (DO) within the system and the relativity of DO and removing nitrogen. The results show that NH4+-N, NO3—-N and DO decrease along the flow direction in the integrated vertical flow constructed wetlands; NO3—-N increased and then decreased along the process; because of the DO of upstream pool is low, so the Total Nitrogen (TN) removing process occurs mainly in the downstream pool.

scholarly journals Purification ability of tail water and optimal hydraulic loading rates in vertical flow constructed wetland

2016 ◽  
Vol 28 (1) ◽  
pp. 114-123
Author(s):  
LIANG Kang ◽  
◽  
CHANG Junjun ◽  
WANG Feihua ◽  
LIU Shuangyuan ◽  
...  
Keyword(s):  
Constructed Wetland ◽  
Vertical Flow ◽  
Loading Rates ◽  
Hydraulic Loading ◽  
Vertical Flow Constructed Wetland ◽  
Tail Water

scholarly journals Lampiran 3B Paper Penurunan Konsentrasi BOD5, COD dan Padatan Tersuspensi pada Air Limbah dengan Menggunakan Teknologi Lahan Basah Buatan (Constructed Wetland)

2021 ◽  
Author(s):  
Philiphi de Rozari
Keyword(s):  
Constructed Wetlands ◽  
Constructed Wetland ◽  
Suspended Solids ◽  
Hydraulic Retention Time ◽  
Low Cost ◽  
Domestic Wastewater ◽  
Suspended Solid ◽  
Vertical Flow ◽  
The Media ◽  
Promising Solution

Constructed wetlands are a promising solution technology to effectively treat domestic wastewater in developing countries at low cost. This paper reports the findings of the effectiveness of sand planted with Thypa latifolia with variation of the length of outflow measured from the bottom of the media in removing BOD5, COD, and suspended solids. The experimental design consisted of 12 vertical flow (VF) mesocosms. There were 3 treatments and one control based on the with variation of the length of outflow measured from the bottom of the media (7, 14, and 21 cm). During the five months, the mesocosms were loaded with syntethic wastewater. The influent had a 2-day hydraulic retention time. Samples were monitored for BOD5, COD and TSS. The results showed the concetration of BOD5, COD and TSS reduced significantly after the wastewater were treated with constructed wetland systems. The trend showed that the constructed wetland systems planted with Thypa latifolia had a better performance in comparison with the control. There were no significant differences of BOD5 COD, and suspended solid outflow among 7, 14 and 21 of constructed wetland systems. This indicated that the length of outflow measured from the bottom of the media did not influence the performance of constructed wetland systems in removing BOD5, COD and TSS

scholarly journals Effects of Partial Saturation on Nitrogen Removal and Bacterial Community in Vertical-Flow Constructed Wetlands

2021 ◽  
Author(s):  
Khadija kraiem ◽  
Hamadi Kallali ◽  
Rim Werheni Ammeri ◽  
salma Bessadok ◽  
Naceur Jedidi
Keyword(s):  
Constructed Wetlands ◽  
Nitrogen Removal ◽  
Constructed Wetland ◽  
Removal Rate ◽  
Vertical Flow ◽  
Partial Saturation ◽  
Denitrifying Bacterium ◽  
Saturation Condition ◽  
Vertical Flow Constructed Wetland ◽  
Kjeldahl Nitrogen

Abstract The laboratory-scale pilot of constructed wetlands has been in operation for six months; (1) an unsaturated vertical flow constructed wetland (UVF-CW), this system was used to represent the classic vertical constructed wetlands, (2) a saturated vertical flow constructed wetland (SVF-CW), to evaluate the effects of the saturated condition on nitrogen removal and composition of the microbial community. The results showed that the saturation condition positiveley influenced the removal efficiencies of the nitrogen,, the aeverage removal rate of the total kjeldahl nitrogen increased from 56% in unsaturated vertical flow constructed wetland (UVF-CW) to 63% in saturated vertical flow constructed wetland ( SVF-CW). In addition, the microbial communities also was affected by the saturation condition, the relative abundances of nitrifying bacterium in UVF-CW are 13.8% (Nitrosomonas), 7.2% (Nitrosospira), 18.1% (Nitrospira) and 15.3% (Nitrobacter). In contrast, in SVF-CW, Nitrosomonas, Nitrosospira, Nitrospira and Nitrobacter only accounted for 6.8%, 5.6%, 7.4% and 10.6% respectively. However, the saturation condition seemed to increase denitrifying bacterium more than three times, in unsaturated vertical flow constructed wetland, only Pseudomonas (6.5%) and Paracoccus (4.85%) were detected, but in saturated vertical flow constructed wetland (SVF-CW), the abundance of Pseudomonas (13.08%) and Paracoccus (9.74%) were increased, and three other groups of denitrifying bacteria were also detected as Zoogloea (3.32%), Thauera (5.41%) and Thiobacillus (3).

Influence of hydraulic loading rate and recirculation on oxygen transfer in a vertical flow constructed wetland

2019 ◽  
Vol 668 ◽  
pp. 988-995 ◽  
Author(s):  
Samara T. Decezaro ◽  
Delmira B. Wolff ◽  
Catiane Pelissari ◽  
Rolando J.M.G. Ramírez ◽  
Thiago A. Formentini ◽  
...  
Keyword(s):  
Constructed Wetland ◽  
Oxygen Transfer ◽  
Loading Rate ◽  
Vertical Flow ◽  
Hydraulic Loading Rate ◽  
Hydraulic Loading ◽  
Vertical Flow Constructed Wetland

Evaluating performance of vertical flow constructed wetland under various hydraulic loading rates in effluent polishing

2011 ◽  
Vol 1 (2) ◽  
pp. 144-151 ◽  
Author(s):  
C. W. Maina ◽  
B. M. Mutua ◽  
S. O. Oduor
Keyword(s):  
Wastewater Treatment ◽  
Constructed Wetland ◽  
Ammonium Nitrogen ◽  
Water Bodies ◽  
Vertical Flow ◽  
Loading Rates ◽  
Hydraulic Loading ◽  
Untreated Wastewater ◽  
Treated Effluent ◽  
Vertical Flow Constructed Wetland

The discharge of untreated wastewater or partially treated effluent and runoff from agricultural fields into water bodies is a major source of surface water pollution worldwide. To mitigate this problem, wastewater treatment using wastewater stabilization ponds and constructed wetlands have been promoted. The performance of such wastewater treatment systems is strongly dependent on their hydraulics, which if not properly considered during design or operation, may result in the partially treated effluent being discharged into water bodies. This paper presents results from a study that was carried out to evaluate the performance of a vertical flow constructed wetland system under varying hydraulic loading regimes. The influent and effluent samples from the constructed wetland were collected and analysed for physical, chemical and biological parameters of importance to water quality based on recommended standard laboratory methods. The data collected was useful in determining the treatment efficiency of the wetland. The hydraulic loading rate applied ranged between 0.014 and 0.174 m/day. Phosphorus reduction for the different hydraulic loading rates ranged between 92 and 47% for lowest and highest loading rates applied respectively. However, ammonium nitrogen reduction was not significantly affected by the different hydraulic loading rates, since the reduction ranged between 97 and 94%.

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