Evaluation of phosphorus retention in a South Florida treatment wetland

2001 ◽  
Vol 44 (11-12) ◽  
pp. 109-115 ◽  
Author(s):  
M.K. Nungesser ◽  
M.J. Chimney
Keyword(s):  
Removal Efficiency ◽  
Nutrient Removal ◽  
Aquatic Vegetation ◽  
South Florida ◽  
Superior Performance ◽  
Stormwater Treatment ◽  
Treatment Wetland ◽  
Operational Conditions ◽  
Macrophyte Community ◽  
Floating Macrophyte

The Everglades Construction Project of the South Florida Water Management District (District) will employ large constructed wetlands known as Stormwater Treatment Areas (STAs) to reduce phosphorus concentrations in runoff entering the Everglades. The District built and operated a prototype STA, the 1,545 ha Everglades Nutrient Removal Project (ENRP), to determine the efficacy of subtropical wetlands for improving regional water quality with a focus on reducing total phosphorus (TP). In five years of operation, the ENRP has consistently exceeded its performance goals of TP outflow concentrations <50 μg P/L and a 75% TP load reduction. Since August 1994, the ENRP has retained 70.3 metric tons of TP that otherwise would have entered the Everglades. When corrected for surface area and inflow TP load, TP removal efficiency was highest in the inflow buffer cell and decreased generally in a downstream fashion through the wetland. High TP removal efficiency in treatment cell 4 was attributed to superior performance of its submerged aquatic vegetation community relative to the emergent and floating macrophyte community in the other cells. Controlled experiments in the District's STA Optimization Research Program will help clarify what effect vegetation and operational conditions may have on nutrient removal in the STAs.

scholarly journals Understanding potential drivers of aquatic metabolism in a subtropical treatment wetland

2020 ◽  
Author(s):  
Paul Julian ◽  
Todd Z. Osborne
Keyword(s):  
Aquatic Vegetation ◽  
Chemical Processes ◽  
Ecosystem Metabolism ◽  
Stormwater Treatment ◽  
Treatment Wetland ◽  
Treatment Area ◽  
Stormwater Treatment Area ◽  
Aquatic Productivity ◽  
Changes Over Time ◽  
Physical And Chemical

AbstractChanges of dissolved oxygen (DO) in aquatic ecosystems integrates dynamic biological, physical and chemical processes that control the rate of ecosystem metabolism. Aquatic ecosystem metabolism can be characterized by the diel change in DO changes over time and is expressed as the net aquatic productivity (NAP). This study investigated aquatic metabolism of dominant emergent and submerged aquatic vegetation (EAV and SAV, respectively) within two treatment flow-ways (FW) of Stormwater Treatment Area 2 (STA-2) in the Everglades ecosystem. The hypothesis of this study is that aquatic metabolism will differ between aquatic vegetation communities with SAV communities will have a greater GPP and ER rate than EAV communities driven by biophysical, hydrodynamic and biogeochemical differences between systems. Aquatic metabolism observed in this study vary spatially (along FWs) and temporally (diel to days) controlled by different effects related biological, physical and chemical processes. This study suggests that ecosystem metabolism is controlled differently across FWs with varying levels of response to loading/transport and water column attributes resulting in differences in organic matter accumulation, C turnover and phosphorus cycling.

scholarly journals Evaluation of nutrient stoichiometric relationships amongst ecosystem compartments of a subtropical treatment wetland. Do we have “Redfield Wetlands”?

2017 ◽  
Author(s):  
Paul Julian ◽  
Stefan Gerber ◽  
Rupesh K Bhomia ◽  
Jill King ◽  
Todd Z. Osborne ◽  
...  
Keyword(s):  
Water Column ◽  
Biogeochemical Cycling ◽  
Terrestrial Ecosystems ◽  
South Florida ◽  
Ground Vegetation ◽  
Stormwater Treatment ◽  
Nutrient Stoichiometry ◽  
Treatment Wetland ◽  
Wetland Ecosystems ◽  
P Limitation

AbstractBackgroundEvaluation of carbon (C), nitrogen (N) and phosphorus (P) ratios in aquatic and terrestrial ecosystems can advance our understanding of biological processes, nutrient cycling and the fate of organic matter (OM) in these ecosystems. Eutrophication of aquatic ecosystems can change the accumulation and decomposition of OM which can alter biogeochemical cycling and alter the base of the aquatic food web. This study investigated nutrient stoichiometry within and among wetland ecosystem compartments (i.e. water column, flocculent, soil and above ground vegetation biomass) of two sub-tropical treatment wetlands with distinct vegetation communities. Two flow-ways (FWs) within the network of Everglades Stormwater Treatment Areas in south Florida (USA) were selected for this study. We evaluated nutrient stoichiometry of these to understand biogeochemical cycling and controls of nutrient removal in a treatment wetland within an ecological stoichiometry context.ResultsThis study demonstrates that C, N, and P stoichiometry can be highly variable among ecosystem compartments and between FWs. Power law slopes of C, N and P within surface water floc, soil and vegetation were significantly different between and along FWs.ConclusionsAssessment of wetland nutrient stoichiometry between and within ecosystem compartments suggests unconstrained stoichiometry related to P that conforms with the notion of P limitation in the ecosystem. Differences in N:P ratios between floc and soil suggest different pathways of organic nutrient accumulation and retention between FWs. Surface nutrient stoichiometry was highly variable and decoupled (or closed to decoupled, by our criteria), in particular with respect to P. We hypothesize that decoupling may be the imprint of variability in inflow nutrient stoichiometry. However, despite active biogeochemical cycles that could act to restore nutrient stoichiometry along the FW, there was little evidence that such balancing occurred, as the degree of stochiometric decoupling in the water column did change with distance downstream. This information is only the beginning of a larger journey to understand stoichiometric processes within wetland ecosystems and how it related to ecosystem function.

Radiation Curable Polysiloxane: Synthesis to Applications

Soft Matter ◽  
2021 ◽  
Author(s):  
Selvan T. Muthamil ◽  
Titash Mondal
Keyword(s):  
Structural Features ◽  
Superior Performance ◽  
Operational Conditions ◽  
Different Types

Among the different types of specialty polymers, polysiloxane finds its position in the pyramid's apex in performance attributes. Unique structural features result in superior performance benefits over wide operational conditions....

scholarly journals The Optimal Width and Mechanism of Riparian Buffers for Storm Water Nutrient Removal in the Chinese Eutrophic Lake Chaohu Watershed

Water ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1489 ◽  
Author(s):  
Xiuyun Cao ◽  
Chunlei Song ◽  
Jian Xiao ◽  
Yiyong Zhou
Keyword(s):  
Removal Efficiency ◽  
Nutrient Removal ◽  
Eutrophic Lake ◽  
Riparian Buffers ◽  
Nutrient Level ◽  
Nitrification Rate ◽  
Lake Chaohu ◽  
Potential Nitrification ◽  
Different Types ◽  
Nutrient Removal Efficiency

Riparian buffers play an important role in intercepting nutrients entering lakes from non-point runoffs. In spite of its ecological significance, little is known regarding the underlying mechanisms of riparian buffers or their optimal width. In this study, we examined nutrient removal efficiency, including the quantity of nutrients and water quality, in the littoral zone of different types of riparian buffers in the watershed around eutrophic Lake Chaohu (China), and estimated the optimal width for different types of riparian buffers for effective nutrient removal. In general, a weak phosphorus (P) adsorption ability and nitrification-denitrification potential in soil resulted in a far greater riparian buffer demand than before in Lake Chaohu, which may be attributed to the soil degradation and simplification of cover vegetation. In detail, the width was at least 23 m (grass/forest) and 130 m (grass) for total P (TP) and total nitrogen (TN) to reach 50% removal efficiency, respectively, indicating a significantly greater demand for TN removal than that for TP. Additionally, wetland and grass/forest riparian buffers were more effective for TP removal, which was attributed to a high P sorption maximum (Qmax) and a low equilibrium P concentration (EPC0), respectively. The high potential nitrification rate (PNR) and potential denitrification rate (PDR) were responsible for the more effective TN removal efficiencies in grass riparian buffers. The nutrient removal efficiency of different types of riparian buffers was closely related with nutrient level in adjacent littoral zones around Lake Chaohu.

scholarly journals Application of electrochemical peroxidation (ECP) process for waste-activated sludge stabilization and system optimization using response surface methodology (RSM)

2018 ◽  
Vol 77 (6) ◽  
pp. 1765-1776 ◽  
Author(s):  
Gagik Badalians Gholikandi ◽  
Khashayar Kazemirad
Keyword(s):  
Response Surface Methodology ◽  
Activated Sludge ◽  
Response Surface ◽  
Removal Efficiency ◽  
Ph Value ◽  
System Optimization ◽  
Waste Activated Sludge ◽  
Operational Conditions ◽  
Sludge Stabilization ◽  
Rsm Optimization

Abstract In this study, the performance of the electrochemical peroxidation (ECP) process for removing the volatile suspended solids (VSS) content of waste-activated sludge was evaluated. The Fe2+ ions required by the process were obtained directly from iron electrodes in the system. The performance of the ECP process was investigated in various operational conditions employing a laboratory-scale pilot setup and optimized by response surface methodology (RSM). According to the results, the ECP process showed its best performance when the pH value, current density, H2O2 concentration and the retention time were 3, 3.2 mA/cm2, 1,535 mg/L and 240 min, respectively. In these conditions, the introduced Fe2+ concentration was approximately 500 (mg/L) and the VSS removal efficiency about 74%. Moreover, the results of the microbial characteristics of the raw and the stabilized sludge demonstrated that the ECP process is able to remove close to 99.9% of the coliforms in the raw sludge during the stabilization process. The energy consumption evaluation showed that the required energy of the ECP reactor (about 1.8–2.5 kWh (kg VSS removed)−1) is considerably lower than for aerobic digestion, the conventional waste-activated sludge stabilization method (about 2–3 kWh (kg VSS removed)−1). The RSM optimization process showed that the best operational conditions of the ECP process comply with the experimental results, and the actual and the predicted results are in good conformity with each other. This feature makes it possible to predict the introduced Fe2+ concentrations into the system and the VSS removal efficiency of the process precisely.

A pilot bioretention system with commercial activated carbon and river sediment-derived biochar for enhanced nutrient removal from stormwater

2019 ◽  
Vol 80 (4) ◽  
pp. 707-716 ◽  
Author(s):  
Min Sang ◽  
Miansong Huang ◽  
Wei Zhang ◽  
Wu Che ◽  
Huichao Sun
Keyword(s):  
Activated Carbon ◽  
Removal Efficiency ◽  
Nutrient Removal ◽  
River Sediment ◽  
Oxygen Demand ◽  
Column Experiment ◽  
Average Mass ◽  
Mass Removal ◽  
The Media ◽  
Removal Efficiencies

Abstract Bioretention is an effective technology for urban stormwater management, but the nutrient removal in conventional bioretention systems is highly variable. Thus, a pilot bioretention column experiment was performed to evaluate the nutrient control of systems with commercial activated carbon and river sediment-derived biochar. Significant chemical oxygen demand (COD) and total phosphorus (TP) leaching were found with the addition of activated carbon and biochar, but total nitrogen (TN) leaching was significantly improved when activated carbon was used as the medium. During a semi-synthetic runoff experiment, the bioretention systems containing two types of fluvial biochar showed relatively better COD and TN control (average mass removal efficiencies and cumulative removal efficiencies) than commercial activated carbon. However, the average TP mass removal efficiency with commercial activated carbon (95% ± 3%) was significantly higher than biochar (48% ± 20% and 56 ± 14%). The addition of biochar in the media increased the nitrogen removal efficiency, and the addition of activated carbon significantly increased the phosphorous removal efficiency. Therefore, both biochar and activated carbon are effective materials for bioretention, and fluvial biochar provides an alternative approach to comprehensively utilize river sediment.

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