scholarly journals Removal Mechanisms in a Tropical Boundary Layer: Quantification of Air Pollutant Removal Rates Around a Heavily Afforested Power Plant

10.5772/18348 ◽  
2011 ◽  
Author(s):  
J. R. ◽  
S. Ghosh
Keyword(s):  
Boundary Layer ◽  
Power Plant ◽  
Air Pollutant ◽  
Pollutant Removal ◽  
Removal Rates ◽  
Removal Mechanisms

scholarly journals Estimating Air Pollution Removal and Monetary Value for Urban Green Infrastructure Strategies Using Web-Based Applications

Land ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 788
Author(s):  
Alessio Russo ◽  
Wing Tung Chan ◽  
Giuseppe T. Cirella
Keyword(s):  
Ecosystem Services ◽  
Green Infrastructure ◽  
Well Being ◽  
Air Pollutant ◽  
Pollutant Removal ◽  
Tree Canopy ◽  
Tree Planting ◽  
City Centre ◽  
Online Tools ◽  
Pollution Removal

More communities around the world are recognizing the benefits of green infrastructure (GI) and are planting millions of trees to improve air quality and overall well-being in cities. However, there is a need for accurate tools that can measure and value these benefits whilst also informing the community and city managers. In recent years, several online tools have been developed to assess ecosystem services. However, the reliability of such tools depends on the incorporation of local or regional data and site-specific inputs. In this communication, we have reviewed two of the freely available tools (i.e., i-Tree Canopy and the United Kingdom Office for National Statistics) using Bristol City Centre as an example. We have also discussed strengths and weaknesses for their use and, as tree planting strategy tools, explored further developments of such tools in a European context. Results show that both tools can easily calculate ecosystem services such as air pollutant removal and monetary values and at the same time be used to support GI strategies in compact cities. These tools, however, can only be partially utilized for tree planting design as they do not consider soil and root space, nor do they include drawing and painting futures. Our evaluation also highlights major gaps in the current tools, suggesting areas where more research is needed.

Effect of the Structure of Composite Ecological Floating Bed on Eutrophic Pollutants Removal in Water

2014 ◽  
Vol 1073-1076 ◽  
pp. 755-758 ◽  
Author(s):  
Gong Di Xu ◽  
Jin Zhao Hu ◽  
Te Mu Le Gang ◽  
Rui Na Liu ◽  
Meii Yu Wu ◽  
...  
Keyword(s):  
Domestic Sewage ◽  
Pollutant Removal ◽  
Removal Rates ◽  
Pollutants Removal ◽  
Static Conditions

By applying the technology of composite ecological floating bed, a research was conducted to compare the eutrophic pollutant removal effects in domestic sewage among different filler proportions under static conditions. The results of proportion comparison experiments showed that the proportion of Plant: Filler = 1:1 had the best effects on NH4+-N with the average removal rates as 97.93%, while as Plants: Filler = 1:1/2 had the best effects on TN and TP with the average removal rates of 89.05% and 91.55% respectively.

scholarly journals Treatment performances of French constructed wetlands: results from a database collected over the last 30 years

2015 ◽  
Vol 71 (9) ◽  
pp. 1333-1339 ◽  
Author(s):  
A. Morvannou ◽  
N. Forquet ◽  
S. Michel ◽  
S. Troesch ◽  
P. Molle
Keyword(s):  
Constructed Wetlands ◽  
Oxygen Demand ◽  
Pollutant Removal ◽  
Vertical Flow ◽  
Removal Rates ◽  
Waste Stabilization Ponds ◽  
Small Communities ◽  
Technical Department ◽  
In Series ◽  
High Chemical Oxygen Demand

Approximately 3,500 constructed wetlands (CWs) provide raw wastewater treatment in France for small communities (<5,000 people equivalent). Built during the past 30 years, most consist of two vertical flow constructed wetlands (VFCWs) in series (stages). Many configurations exist, with systems associated with horizontal flow filters or waste stabilization ponds, vertical flow with recirculation, partially saturated systems, etc. A database analyzed 10 years earlier on the classical French system summarized the global performances data. This paper provides a similar analysis of performance data from 415 full-scale two-stage VFCWs from an improved database expanded by monitoring data available from Irstea and the French technical department. Trends presented in the first study are confirmed, exhibiting high chemical oxygen demand (COD), total suspended solids (TSS) and total Kjeldahl nitrogen (TKN) removal rates (87%, 93% and 84%, respectively). Typical concentrations at the second-stage outlet are 74 mgCOD L−1, 17 mgTSS L−1 and 11 mgTKN L−1. Pollutant removal performances are summarized in relation to the loads applied at the first treatment stage. While COD and TSS removal rates remain stable over the range of applied loads, the spreading of TKN removal rates increases as applied loads increase.

Pollutant removal mechanisms in a bio-diatomite dynamic membrane reactor for micro-polluted surface water purification

Desalination ◽  
2012 ◽  
Vol 293 ◽  
pp. 38-45 ◽  
Author(s):  
Huaqiang Chu ◽  
Bingzhi Dong ◽  
Yalei Zhang ◽  
Xuefei Zhou ◽  
Zhenxun Yu
Keyword(s):  
Surface Water ◽  
Water Purification ◽  
Membrane Reactor ◽  
Pollutant Removal ◽  
Dynamic Membrane ◽  
Removal Mechanisms

scholarly journals Improving the Treatment Performance of Low Impact Development Practices—Comparison of Sand and Bioretention Soil Mixtures Using Column Experiments

Water ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1210
Author(s):  
Abtin Shahrokh Hamedani ◽  
Arianne Bazilio ◽  
Hanieh Soleimanifar ◽  
Heather Shipley ◽  
Marcio Giacomoni
Keyword(s):  
Phosphorus Removal ◽  
Low Impact Development ◽  
Pollutant Removal ◽  
Control Measures ◽  
Column Experiments ◽  
Removal Rates ◽  
Treatment Performance ◽  
Soil Mixtures ◽  
Limestone Sand ◽  
The Impact

Low impact development (LID) practices, such as bioretention and sand filter basins, are stormwater control measures designed to mitigate the adverse impacts of urbanization on stormwater. LID treatment performance is highly dependent on the media characteristics. The literature suggests that bioretention media often leach nutrients in the stormwater effluent. The objective of this study was to analyze the treatment performance of different sand and bioretention soil mixtures. Specifically, this investigation aimed to answer whether the use of limestone and recycled glass could improve the treatment performance of bioretention systems. Column experiments were designed to assess (1) the removal efficiencies of different sand and bioretention soil mixtures and (2) the impact of plant uptake on removal rates. Enhanced pollutant removal was observed for the custom blends with addition of limestone sand, indicating mean dissolved and total phosphorus removal of 44.5% and 32.6% respectively, while the conventional bioretention soil mixtures leached phosphorus. Moreover, improved treatment of dissolved and total copper was achieved with mean removal rates of 70.7% and 93.4%, respectively. The results suggest that the nutrient effluent concentration decreased with the addition of plants, with mean phosphorus removal of 72.4%, and mean nitrogen removal of 22% for the limestone blend.

Hydraulic tracer studies in a pilot scale subsurface flow constructed wetland

1997 ◽  
Vol 35 (5) ◽  
pp. 189-196 ◽  
Author(s):  
Andrew C. King ◽  
Cynthia A. Mitchell ◽  
Tony Howes
Keyword(s):  
Dispersion Model ◽  
Plant Root ◽  
Subsurface Flow ◽  
Plug Flow ◽  
Pilot Scale ◽  
Pollutant Removal ◽  
Tracer Studies ◽  
Operational Strategies ◽  
Design Procedures ◽  
Removal Mechanisms

Current design procedures for Subsurface Flow (SSF) Wetlands are based on the simplifying assumptions of plug flow and first order decay of pollutants. These design procedures do yield functional wetlands but result in over-design and inadequate descriptions of the pollutant removal mechanisms which occur within them. Even though these deficiencies are often noted, few authors have attempted to improve modelling of either flow or pollutant removal in such systems. Consequently the Oxley Creek Wetland, a pilot scale SSF wetland designed to enable rigorous monitoring, has recently been constructed in Brisbane, Australia. Tracer studies have been carried out in order to determine the hydraulics of this wetland prior to commissioning it with settled sewage. The tracer studies will continue during the wetland's commissioning and operational phases. These studies will improve our understanding of the hydraulics of newly built SSF wetlands and the changes brought on by operational factors such as biological films and wetland plant root structures. Results to date indicate that the flow through the gravel beds is not uniform and cannot be adequately modelled by a single parameter, plug flow with dispersion, model. We have developed a multiparameter model, incorporating four plug flow reactors, which provides a better approximation of our experimental data. With further development this model will allow improvements to current SSF wetland design procedures and operational strategies, and will underpin investigations into the pollutant removal mechanisms at the Oxley Creek Wetland.

scholarly journals Graphene-Modulated Removal Performance of Nitrogen and Phosphorus Pollutants in a Sequencing Batch Chlorella Reactor

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2181 ◽  
Author(s):  
Gonghan Xia ◽  
Wenlai Xu ◽  
Qinglin Fang ◽  
Zishen Mou ◽  
Zhicheng Pan
Keyword(s):  
Optical Microscopy ◽  
Sewage Treatment ◽  
Ammonia Nitrogen ◽  
Pollutant Removal ◽  
Plate Count ◽  
Nitrogen And Phosphorus ◽  
Removal Rates ◽  
Practical Support ◽  
Plate Count Method ◽  
The Impact

In this work, the influence of graphene on nitrogen and phosphorus in a batch Chlorella reactor was studied. The impact of graphene on the removal performance of Chlorella was investigated in a home-built sewage treatment system with seven identical sequencing batch Chlorella reactors with graphene contents of 0 mg/L (T1), 0.05 mg/L (T2), 0.1 mg/L (T3), 0.2 mg/L (T4), 0.4 mg/L (T5), 0.8 mg/L (T6) and 10 mg/L (T7). The influence of graphene concentration and reaction time on the pollutant removal performance was studied. The malondialdehyde (MDA) and total superoxide dismutase (SOD) concentrations in each reactor were measured, and optical microscopy and scanning electron microscopy (SEM) characterizations were performed to determine the related mechanism. The results show that after 168 h, the total nitrogen (TN), ammonia nitrogen (AN) and total phosphorus (TP) removal rates of reactors T1–T7 become stable, and the TN, AN and TP removal rates were gradually reduced with increasing graphene concentration. At 96 h, the concentrations of both MDA and SOD in T1–T7 gradually increased as the graphene concentration increased. In optical microscopy and SEM measurements, it was found that graphene was adsorbed on the surface of Chlorella, and entered Chlorella cells, deforming and reducing Chlorella. Through the blood plate count method, we estimated an average Chlorella reduction of 16%. According to the water quality and microscopic experiments, it can be concluded that the addition of graphene causes oxidative damage to microalgae and destruction of the Chlorella cell wall and cell membrane, inhibiting the nitrogen and phosphorus removal in Chlorella reactors. This study provides theoretical and practical support for the safe use of graphene.

scholarly journals Oxidation photochemistry in the Southern Atlantic boundary layer: unexpected deviations of photochemical steady state

2011 ◽  
Vol 11 (3) ◽  
pp. 7045-7093 ◽  
Author(s):  
Z. Hosaynali Beygi ◽  
H. Fischer ◽  
H. D. Harder ◽  
M. Martinez ◽  
R. Sander ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Steady State ◽  
Atlantic Ocean ◽  
Atmospheric Chemistry ◽  
Marine Boundary Layer ◽  
Air Pollutant ◽  
Photochemical Oxidant ◽  
Important Region ◽  
Atmospheric Observations ◽  
Oxidation Efficiency

Abstract. Ozone (O3) is a photochemical oxidant, an air pollutant and a greenhouse gas. As the main precursor of the hydroxyl radical (OH) it strongly affects the oxidation power of the atmosphere. The remote marine boundary layer (MBL) is considered an important region in terms of chemical O3 loss; however surface-based atmospheric observations are sparse and the photochemical processes are not well understood. To investigate the photochemistry under the clean background conditions of the Southern Atlantic Ocean, ship measurements of NO, NO2, O3, JNO2, J(O1D), HO2, OH, ROx and a range of meteorological parameters were carried out. The concentrations of NO and NO2 measured on board the French research vessel Marion-Dufresne (28° S–57° S, 46° W–34° E) in March 2007, are among the lowest yet observed. The data is evaluated for consistency with photochemical steady state (PSS) conditions, and the calculations indicate substantial deviations from PSS (Φ>1). The deviations observed under low NOx conditions (5–25 pptv) demonstrate a remarkable upward tendency in the Leighton ratio (used to characterize PSS) with increasing NOx mixing ratio and JNO2 intensity. It is a paradigm in atmospheric chemistry that OH largely controls the oxidation efficiency of the atmosphere. However, evidence is growing that for unpolluted low-NOx (NO + NO2) conditions the atmospheric oxidant budget is poorly understood. Nevertheless, for the very cleanest conditions, typical for the remote marine boundary layer, good model agreement with measured OH and HO2 radicals has been interpreted as accurate understanding of baseline photochemistry. Here we show that such agreement can be deceptive and that a yet unidentified oxidant is needed to explain the photochemical conditions observed at 40°–60° S over the Atlantic Ocean.

Sign in / Sign up

Export Citation Format

Share Document