Relationship between hydraulic efficiency and phosphorus removal in a submerged aquatic vegetation-dominated treatment wetland

Dierberg, Forrest E.; Juston, John J.; DeBusk, Thomas A.; Pietro, Kathleen; Gu, Baojing

doi:10.1016/j.ecoleng.2004.12.018

Cited by 97 publications

(39 citation statements)

References 11 publications

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“…Residence time distribution (RTD) aids in characterizing hydraulics and has been shown to have a strong correlation with treatment efficiencies [35,37,45]. The hydraulic tracer assessment determined that the measured residence time (ta) was 15.0 d, which was similar to the nominal design residence time (tn) of 14.5 d (Figure 5).…”

Section: Residence Time Monitoringmentioning

confidence: 71%

Performance of an Agricultural Wetland-Reservoir-Irrigation Management System

Haverstock

Madani

Baldé

et al. 2017

Water

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Constructed wetlands (CW) have gained recognition as a management option for the treatment of various agricultural wastewaters. This study involved the design, construction, and initial evaluation of a wetland-reservoir-irrigation (WRI) system. The system was established in Truro, Nova Scotia, Canada, with the goal to capture, treat, and re-use agricultural sub-surface drainage water. It consisted of a 1.8-ha area of a cropped field that was systematically tile drained. Drainage water was directed through a 2-cell CW and then into a reservoir-irrigation pond. Flow rate hydraulics, residence time distributions, and treatment efficiencies for nitrate-nitrogen (NO 3 − -N) and Escherichia coli (E. coli) were monitored for 14 months. Mass reductions of NO 3 − -N and E. coli from the CW were 67.6% and 63.3%, respectively. However, average E. coli concentrations increased to 178 CFU 100 mL −1 in the reservoir during the warm season. It may therefore be best to use reservoir water for irrigation of crops that are not consumed raw. To aid in the future design of similar systems, mean first-order rate constants (k s ) for NO 3 − -N and E. coli were calculated to be 8.0 and 6.4 m y −1 , respectively. The volume of water collected in the reservoir exceeded typical irrigation requirements of the drained land and could therefore provide irrigation to additional land beyond the drainage area.

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Section: Residence Time Monitoringmentioning

confidence: 71%

Performance of an Agricultural Wetland-Reservoir-Irrigation Management System

Haverstock

Madani

Baldé

et al. 2017

Water

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“…Capacity for retention may be maxi- mized under low hydraulic loading (and hence long retention time) as a result of lengthened exposure of water to microbial processes. Dierberg et al (2005) demonstrated that phosphorus removal was higher in wetlands with longer hydraulic retention periods, while Diemont (2006) reported similar patterns for total phosphorus and BOD removal in tropical treatment systems in Honduras. Although retention time is generally lower under high hydraulic loading rates, dissolved oxygen is higher (perhaps as a result of water movement and churning) allowing for creation of aerobic conditions and reduction in pollutants like organic matter and ammonia.…”

Section: Hydraulic Loading and Nutrient Retention Ratesmentioning

confidence: 94%

Tropical treatment wetlands dominated by free-floating macrophytes for water quality improvement in Costa Rica

Nahlik

Mitsch

2006

Ecological Engineering

145

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a b s t r a c tFive tropical treatment wetlands dominated by floating aquatic plants and constructed to deal with a variety of wastewaters were compared for their effectiveness in treating organic matter and nutrients in the Parismina River Basin in eastern Costa Rica. Wastewaters were from a dairy farm, a dairy processing plant, a banana paper plant, and a landfill. Four of the five wetland systems were effective in reducing nutrient levels of effluents before water was discharged into rivers. Ammonia levels in water entering most wetlands were considerably higher than ambient (i.e., riverine) levels; concentrations were reduced by as much as 92% in the wetlands and retained at a maximum rate of 166 g N m −2 year −1 .Nitrate nitrogen removal was variable, but occurred in low concentrations in the inflows (less than 1 mg N L −1 ). Phosphate phosphorus was present in high levels but was effectively reduced through the wetlands (92 and 45% reductions through dairy farm wetlands, 83% reduction through banana paper wetlands, and 80% reduction through dairy processing wetlands). Retention of phosphate phosphorus ranged from 0.1 to 10.7 g P m −2 year −1 in the treatment wetlands. Dissolved oxygen in the wetland outflows were ≤2 mg L −1 in three of the sampled wetlands, most likely a result of the abundant free-floating macrophytes that sheltered the water from diffusion and shaded aquatic productivity. The efficacy of these created wetlands to treat effluents from different sources varied, and modified wetland designs or active management may be necessary to improve water quality even further.Recommendations on tropical wetland design and management are presented, as are suggestions for implementing this ecological engineering approach with farmers in Central America.

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“…The calibration parameter is the removal rate coefficient, k. Hydraulic models can account for flow patterns intermediate to plug flow or perfect mixing, through the use of the tanks in series (TIS) model. Several large-scale wetlands have been tracer tested, and produced a central tendency of about N = 4-6 for cells or flow paths of a large wetland (see, for instance, [40][41][42]). …”

Section: Steady State Modelsmentioning

confidence: 99%

“…As a consequence, tracer testing has been utilized to assess non-ideal flow effects in large wetlands [40][41][42][43]. Results are extremely variable, with the tanks-in-series (TIS) characterization ranging from 1 to 9.…”

Section: Internal Patternsmentioning

confidence: 99%

Large Constructed Wetlands for Phosphorus Control: A Review

Kadlec¹

2016

Water

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This paper reviews aspects of the performance of large (>40 ha) constructed treatment wetlands intended for phosphorus control. Thirty-seven such wetlands have been built and have good data records, with a median size of 754 ha. All are successfully removing phosphorus from a variety of waters. Period of record median concentration reductions were 71%, load reductions 0.77 gP¨m´2¨year´1, and rate coefficients 12.5 m¨year´1. Large wetlands have a narrower performance spectrum than the larger group of all sizes. Some systems display startup trends, ranging to several years, likely resulting from antecedent soil and vegetation conditions. There are internal longitudinal gradients in concentration, which vary with lateral position and flow conditions. Accretion in inlet zones may require attention. Concentrations are reduced to plateau values, in the range of about 10-50 mgP¨m´3. Vegetation type has an effect upon performance measures, and its presence facilitates performance. Trends in the performance measures over the history of individual systems display only small changes, with both increases and decreases occurring. Such trends remove little of the variance in behavior. Seasonality is typically weak for steady flow systems, and most variability appears to be stochastic. Stormwater systems display differences between wet and dry season behavior, which appear to be flow-driven. Several models of system performance have been developed, both steady and dynamic.

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Relationship between hydraulic efficiency and phosphorus removal in a submerged aquatic vegetation-dominated treatment wetland

Cited by 97 publications

References 11 publications

Performance of an Agricultural Wetland-Reservoir-Irrigation Management System

Performance of an Agricultural Wetland-Reservoir-Irrigation Management System

Tropical treatment wetlands dominated by free-floating macrophytes for water quality improvement in Costa Rica

Large Constructed Wetlands for Phosphorus Control: A Review

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