scholarly journals Multistage Constructed Wetland in the Treatment of Greywater under Tropical Conditions: Performance, Operation, and Maintenance

Recycling ◽  
2021 ◽  
Vol 6 (4) ◽  
pp. 63
Author(s):  
Fernando J. C. Magalhães Filho ◽  
José C. M. de Souza Filho ◽  
Paula L. Paulo
Keyword(s):  
Constructed Wetland ◽  
Oxygen Demand ◽  
Loading Rates ◽  
Multistage System ◽  
Operation And Maintenance ◽  
Multi Stage ◽  
Tropical Conditions ◽  
Proper Design ◽  
System Sustainability ◽  
Onsite Treatment

Greywater (GW) can be separated in different fractions where the kitchen component might be included. Constructed wetland (CW) systems are commonly used for the onsite treatment of GW, and the fraction treated might impact the performance, operation, and maintenance. These aspects are still poorly explored in the literature and are of importance for a proper design and system sustainability. In this study, a multi-stage household-scale CW system composed of a horizontal flow (HF), followed by a vertical flow (VF) unit, was monitored over 1330 days, focusing on different GW fractions and hydraulic and organic loading rates. The biochemical oxygen demand (BOD) was ~50% lower without the kitchen sink component (GWL) in the system inlet, while no drop was observed in the chemical oxygen demand (COD). Treatment with the GWL component caused a sudden drop in the hydraulic loading rate applied at the HF-CW (~114 to 35 mm per day) and the VF-CW (~230 to 70 mm per day). Even when the HF-CW received ~90 gCOD m−2 per day (GW), the multistage system reached a COD removal of 90%. The lower BOD load when treating GWL avoids clogging and decreases the frequency of maintenance. These variables can be used for the optimal design and operation of a CW, contributing with empirical data to CW guidelines in Brazil, and could additionally be expanded for application in other countries with similar climates.

The effect of a vertical flow filter bed on a hybrid constructed wetland system

2005 ◽  
Vol 51 (9) ◽  
pp. 137-144 ◽  
Author(s):  
A. Noorvee ◽  
E. Põldvere ◽  
Ü. Mander
Keyword(s):  
Constructed Wetland ◽  
Flow System ◽  
Subsurface Flow ◽  
Oxygen Demand ◽  
Vertical Flow ◽  
Efficient Removal ◽  
Loading Rates ◽  
Purification Efficiency ◽  
Wetland System ◽  
Filter Bed

Data from 18 sampling wells in Kodijärve horizontal subsurface flow (HSSF) constructed wetland (CW) (South Estonia) is presented and differences in purification efficiencies inside the HSSF CW are calculated. Temporarily anaerobic conditions in the Kodijärve HSSF system did not allow efficient removal of BOD7, NH4-N, Ntot and Ptot. In 2002 a vertical subsurface flow filter was constructed to enhance aeration. The design of the system was based simply on the oxygen demand of the wastewater and on the aeration potential of vertical flow wetlands. The vertical flow system has shown satisfactory results. The purification efficiency of BOD7 in the Kodijärve CW has improved significantly and there has been a slight increase in purification efficiencies of NH4-N and Ntot. On the ohther hand, the removal efficiency of Ptot has decreased significantly. Although, the mass loading rates have increased, mass removal rates of all four parameters have improved significantly. Nevertheless, optimization of the constructed wetland system is essential in order to meet effluent standards during wintertime.

Application of constructed wetlands to treat some toxic wastewaters under tropical conditions

1996 ◽  
Vol 34 (11) ◽  
pp. 165-171 ◽  
Author(s):  
C. Polprasert ◽  
N. P. Dan ◽  
N. Thayalakumaran
Keyword(s):  
Constructed Wetlands ◽  
Constructed Wetland ◽  
Free Water ◽  
Operating Conditions ◽  
Organic Loading ◽  
Metal Compounds ◽  
Loading Rates ◽  
Tropical Conditions ◽  
Wetland System ◽  
Stems And Leaves

This study evaluated the potential of a free water surface constructed wetland system in treating some toxic wastewaters (i.e. phenolic and heavy metals). In a temperature range of 22–30°C, the constructed wetland units, whose hydraulic retention times (HRT) were 5–7 days, could remove more than 99% of the input phenol when they were operated at or below the organic loading rates (OLR) and influent phenol concentrations of 270 kg COD/(ha.d) and 400 mg/l, respectively. The effluent dissolved oxygen (DO) levels were 4–7 mg/l at OLR of 40–140 kg COD/(ha.d), but these DO levels decreased to 0.2–0.3 mg/l when the OLR were increased to 165–270 kg COD/(ha.d). Under similar operating conditions, the constructed wetland units could remove more than 99% of the applied chromium (Cr) and nickel (Ni), when either the Cr or Ni influent concentrations were 1–50 mg/l. The phenolic and heavy metal compounds were found to accumulate mostly at the roots of Typha, followed by the stems and leaves.

Nutrients Removal from Secondary Effluent by Using Different Constructed Wetland Systems

2012 ◽  
Vol 518-523 ◽  
pp. 2155-2160
Author(s):  
Xue Min Xiang ◽  
Xiao Bai Zhou ◽  
Xiao Kun Wang ◽  
Ji Ti Zhou ◽  
Ren Wang
Keyword(s):  
Constructed Wetland ◽  
Removal Rate ◽  
Feeding Strategy ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Control Treatment ◽  
Feeding Strategies ◽  
Secondary Effluent ◽  
Intermittent Feeding ◽  
Multi Stage

Constructed wetland was recognized as an economic and ecological-friendly technique to reduce excess nitrogen (N) and phosphorus (P) in secondary effluent from sewage treatment plants. In this study, the removal capacity of non-planted control treatment, one stage constructed wetland with different feeding strategies, and multi-stage constructed wetland on chemical oxygen demand (COD), total nitrogen (TN), ammonia nitrogen (NH4+-N) and total phosphorus (TP)were evaluated. The results showed that all the planted treatments displayed superior removal efficiency for COD and nutrients in compare with the non-planted control treatment. The feeding strategy could influence COD andN removal rate that the averageremoval rate of the COD, TN, and NH4+-N in intermittent feeding treatment (61.3%, 52.6% and 88.7%) was much higher than continuous feeding treatment (46.8%, 20.6% and 73.9%). Higher TN and TP removal rate was observed in multi-stage constructed wetland (74.1% and 98.1%) than the single-stage constructed wetland (20.6% and 96.9%). This implied that intermittent feeding strategy and the multi-stage constructed wetland may have a good potential for removing nutrients from secondary effluent.

scholarly journals Potential of integrated vertical and horizontal flow constructed wetland with native plants for sewage treatment under different hydraulic loading rates

2017 ◽  
Vol 76 (2) ◽  
pp. 434-442 ◽  
Author(s):  
Xuan Cuong Nguyen ◽  
Dinh Duc Nguyen ◽  
Nguyen Thi Loan ◽  
Soon Woong Chang
Keyword(s):  
Constructed Wetland ◽  
Sewage Treatment ◽  
Oxygen Demand ◽  
Pilot Scale ◽  
Ammonium Nitrogen ◽  
Horizontal Flow ◽  
Most Probable Number ◽  
Probable Number ◽  
Loading Rates ◽  
Hydraulic Loading

In this study, a pilot-scale integrated constructed wetland with vertical flow (VF) and horizontal flow (HF) in series was designed and investigated to evaluate sewage wastewater treatment capacity. The VF unit was planted with Canna indica and was 1.2 m long, 1.2 m wide, and 1.2 m high; whereas the HF unit contained Colocasia esculenta and was 3.0 m long, 1.0 m wide, and 1.0 m high. The system was operated under different hydraulic loading rates (HLRs) of 0.1, 0.2, and 0.15 m/d. The effluent concentrations differed as HLR changed, and the means were total suspended solids (TSS): 87 mg/L; biological oxygen demand (BOD5): 31 mg/L; chemical oxygen demand (CODCr): 59 mg/L; ammonium nitrogen (NH4-N): 5.3 mg/L; nitrate nitrogen NO3-N: 8.4 mg/L; total nitrogen (TN): 7.1 mg/L; phosphate (PO4-P): 0.9 mg/L; and total coliforms (TCol): 1,485 most probable number (MPN)/100 mL. The average removal efficiencies for TSS, BOD5, TN, NH4-N, PO4-P, and TCol were 28.3, 74.9, 79, 76.2, 3.6, and 82%, respectively. There were significant differences in the effluent concentrations among the three HLRs (P < 0.05), except for PO4-P.

Treatment of Different Wastewaters from Pulp and Paper Industry in Methane Reactors

1985 ◽  
Vol 17 (1) ◽  
pp. 223-230 ◽  
Author(s):  
P K Latola
Keyword(s):  
Power Plant ◽  
Paper Industry ◽  
Granular Sludge ◽  
Paper Mill ◽  
Pulp And Paper Industry ◽  
Pulp And Paper ◽  
Plastic Foam ◽  
Loading Rates ◽  
Multi Stage ◽  
Removal Efficiencies

A wastewater from an integrated paper mill with a COD of 1200 mg/dm3 was anaerobically treated in a multi-stage reactor. The BOD7 removal efficiencies of 60-75 % were achieved at maximal loading rates of 5-6 kg COD/m3d and HRT of 4-6 hours due to the granular sludge. Industrial sulphite evaporator condensates from Ca- and Na-processes were treated in anaerobic filters containing light gravel, plastic foam and power plant slag as filter media. The BOD7 removals of 78 % on average were achieved at loading rates of 1.8-3.3 kg COD/m3d with Ca-process evaporator condensates and 80 % BOD7 removals were achieved with Na-process condensates at loading rates of 3.5-4.1 kg COD/m3d.

Comparative study of domestic wastewater treatment efficiencies between facultative pond and water spinach pond

1995 ◽  
Vol 32 (3) ◽  
pp. 263-270 ◽  
Author(s):  
Seni Karnchanawong ◽  
Jaras Sanjitt
Keyword(s):  
Growth Rates ◽  
Domestic Wastewater ◽  
Pilot Scale ◽  
Organic Content ◽  
Water Spinach ◽  
Removal Rates ◽  
Mass Removal ◽  
Loading Rates ◽  
Tropical Conditions ◽  
Average Water

Two pilot-scale studies were comparatively conducted under tropical conditions during December 1992 to September 1993. One study involved facultative ponds(FP) and the others water spinach ponds(SP). Four rectangular concrete ponds, 0.8 m × 2.4 m × 1.1 m (width × length × depth), were employed to treat the Chiang Mai University campus wastewater. Water spinach (Ipomoea aquatica) was planted in two of the ponds. The influent characteristics noted showed a low organic content, i.e. BOD 25.4-29.9 mg/l, with BOD:N ratio around 1:1. The investigations were conducted using the following hydraulic retention times (HRT): 1.6, 2, 2.7, 4, 8 and 16 d. The results showed that the BOD, COD and SS mass removal rates increased as the mass loading rates increased and the SP was significantly more effective in reducing the organic content than the FP. No relationship was found between TN mass removal and the loading rates. However, the TP mass removal rates in the SP and the FP were rather low and were considered to be insignificant. It was observed that SS accumulated in the water spinach root systems which tended to act as a strainer. This process led to plant growth inhibition and finally die-off. The average water spinach growth rates varied from 37 to 107 g wet wt./(m2.d) and no relationship was established between the growth rates and the HRT.

Anaerobic Thermophilic (55°C) Treatment of TMP Whitewater in Reactors Based on Biomass Attachment and Entrapment

1999 ◽  
Vol 40 (11-12) ◽  
pp. 67-75 ◽  
Author(s):  
Sigrun J. Jahren ◽  
Jukka A. Rintala ◽  
Hallvard Ødegaard
Keyword(s):  
Granular Sludge ◽  
Biofilm Reactor ◽  
Upflow Anaerobic Sludge Blanket ◽  
Hybrid Reactor ◽  
Anaerobic Sludge ◽  
Loading Rates ◽  
Anaerobic Reactors ◽  
Multi Stage ◽  
Degradation Rates ◽  
Thermomechanical Pulping

Thermomechanical pulping (TMP) whitewater was treated in thermophilic (55°C) anaerobic laboratory-scale reactors using three different reactor configurations. In all reactors up to 70% COD removals were achieved. The anaerobic hybrid reactor, composed of an upflow anaerobic sludge blanket (UASB) and a filter, gave degradation rates up to 10 kg COD/m3d at loading rates of 15 kg COD/m3d and hydraulic retention time (HRT) of 3.1 hours. The anaerobic multi-stage reactor, consisting of three compartments, each packed with granular sludge and carrier elements, gave degradation rates up to 9 kg COD/m3d at loading rates of 15-16 kg COD/m3d, and HRT down to 2.6 hours. Clogging and short circuiting eventually became a problem in the multi-stage reactor, probably caused by too high packing of the carriers. The anaerobic moving bed biofilm reactor performed similar to the other reactors at loading rates below 1.4 kg COD/m3d, which was the highest loading rate applied. The use of carriers in the anaerobic reactors allowed short HRT with good treatment efficiencies for TMP whitewater.

Field study on N2O emission from subsurface wastewater infiltration system under variable loading rates and drying-wetting cycles

2017 ◽  
Vol 76 (8) ◽  
pp. 2158-2166 ◽  
Author(s):  
Ying-Hua Li ◽  
Hai-Bo Li ◽  
Xin-Yang Xu ◽  
Si-Yao Xiao ◽  
Si-Qi Wang ◽  
...  
Keyword(s):  
Field Study ◽  
Conversion Rate ◽  
Oxygen Demand ◽  
N2o Emission ◽  
Conversion Ratio ◽  
Gas Chromatograph ◽  
Variable Loading ◽  
N2o Production ◽  
Loading Rates ◽  
Operation Conditions

In this field study, the impacts of influent loadings and drying-wetting cycles on N2O emission in a subsurface wastewater infiltration (SWI) system were investigated. N2O emitted under different operation conditions were quantified using static chamber and gas chromatograph techniques. N2O conversion rate decreased from 6.6 ± 0.1% to 2.7 ± 0.1% with an increase in hydraulic loading (HL) from 0.08 to 0.24 m3/m2·d. By contrast, N2O conversion rate increased with increasing pollutant loading (PL) up to 8.2 ± 0.5% (PL 4.2 g N/m2·d) above which conversion rate decreased, confirming that N2O production was under the interaction of nitrification and denitrification. Taking into consideration the pollutants (chemical oxygen demand (COD), NH4+-N, NO3−-N and total nitrogen (TN)) removal ratio and N2O emission, optimal loading ranges and drying-wetting modes were suggested as HL 0.08–0.12 m3/m2·d, PL 3.2–3.7 g N/m2·d and 12 h:12 h, respectively. The results revealed that in SWI systems, conversion ratio of influent nitrogen to N2O could be between 4.5% and a maximum of 7.0%.

scholarly journals Pilot-scale study of vertical flow constructed wetland combined with trickling filter and ferric chloride coagulation: influence of irregular operational conditions

2015 ◽  
Vol 71 (7) ◽  
pp. 1088-1096 ◽  
Author(s):  
B. Kim ◽  
M. Gautier ◽  
G. Olvera Palma ◽  
P. Molle ◽  
P. Michel ◽  
...  
Keyword(s):  
Constructed Wetland ◽  
Phosphorus Removal ◽  
Water Saturation ◽  
Oxygen Demand ◽  
Pilot Scale ◽  
Saturation Level ◽  
Vertical Flow ◽  
Trickling Filter ◽  
Operational Conditions ◽  
Vertical Flow Constructed Wetland

The aim of this study was to characterize the efficiency of an intensified process of vertical flow constructed wetland having the following particularities: (i) biological pretreatment by trickling filter, (ii) FeCl3 injection for dissolved phosphorus removal and (iii) succession of different levels of redox conditions along the process line. A pilot-scale set-up designed to simulate a real-scale plant was constructed and operated using real wastewater. The influences of FeCl3 injection and water saturation level within the vertical flow constructed wetland stage on treatment performances were studied. Three different water saturation levels were compared by monitoring: suspended solids (SS), total phosphorus (TP), dissolved chemical oxygen demand (COD), ammonium, nitrate, phosphate, iron, and manganese. The results confirmed the good overall efficiency of the process and the contribution of the trickling filter pretreatment to COD removal and nitrification. The effects of water saturation level and FeCl3 injection on phosphorus removal were evaluated by analysis of the correlations between the variables. Under unsaturated conditions, good nitrification and no denitrification were observed. Under partly saturated conditions, both nitrification and denitrification were obtained, along with a good retention of SSs. Finally, under saturated conditions, the performance was decreased for almost all parameters.

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