Pollutant transformation performance in a peri-urban African wetland system receiving point source effluent and diffuse source pollutant inputs

2007 ◽  
Vol 7 (3-4) ◽  
pp. 201-206
Author(s):  
Herbert John Bavor ◽  
Michael Waters
Keyword(s):  
Point Source ◽  
Diffuse Source ◽  
Pollutant Transformation ◽  
Wetland System

scholarly journals From point source to diffuse source of contaminants: The example of mercury dispersion in the Paglia River (Central Italy)

CATENA ◽  
2019 ◽  
Vol 172 ◽  
pp. 488-500 ◽  
Author(s):  
Antonella Colica ◽  
Marco Benvenuti ◽  
Laura Chiarantini ◽  
Pilario Costagliola ◽  
Pierfranco Lattanzi ◽  
...  
Keyword(s):  
Point Source ◽  
Central Italy ◽  
Diffuse Source ◽  
Paglia River

Non-point source pesticide removal by a mountainous wetland

2002 ◽  
Vol 46 (6-7) ◽  
pp. 199-206 ◽  
Author(s):  
C.M. Kao ◽  
J.Y. Wang ◽  
K.F. Chen ◽  
H.Y. Lee ◽  
M.J. Wu
Keyword(s):  
Water Quality ◽  
Point Source ◽  
Surface Water Quality ◽  
Storm Events ◽  
Agricultural Lands ◽  
Pesticide Removal ◽  
Nps Pollution ◽  
Natural Wetlands ◽  
Wetland System ◽  
Water Quality Deterioration

Non-point source (NPS) pollution is believed to be one of the major causes of impairment of water bodies. Among NPS pollution, agricultural NPS pollution is considered to be the largest single category resulting in water quality deterioration. Pesticides are some the most ubiquitous of these agricultural NPS pollutants. In this study, a mountainous wetland was selected to investigate the effects of the natural wetland system on the NPS pesticide (atrazine) removal to maintain the surface water quality. The selected wetland receives water from two unnamed creeks, which drain primarily upgradient agricultural lands. Wetland investigation and monitoring were conducted from November 1999 to March 2001. Major storm events and baseline water quality samples were analyzed. Field results indicate that the wetland was able to remove NPS atrazine flushed from the upgradient agricultural lands after the occurrence of storm events. Laboratory aerobic and anaerobic bioreactor experiments were conducted to evaluate the biodegradation of atrazine under the intrinsic conditions of the wetland system. Microbial enumeration was conducted for a quick screen of bacterial activity in the studied wetland. Results from the study suggest that the methanogenesis process was possibly the dominant biodegradation pattern, and atrazine can be degraded under reductive dechlorinating conditions when sufficient intrinsic organic matter was provided. Results from this study can provide us with further knowledge on pesticide removal mechanisms in natural wetlands and evaluate the role of wetlands in controlling pesticide pollutants from stormwater runoff.

Using a constructed wetland for non-point source pollution control and river water quality purification: a case study in Taiwan

2010 ◽  
Vol 61 (10) ◽  
pp. 2549-2555 ◽  
Author(s):  
C. Y. Wu ◽  
C. M. Kao ◽  
C. E. Lin ◽  
C. W. Chen ◽  
Y. C. Lai
Keyword(s):  
Water Quality ◽  
Wastewater Treatment ◽  
Quality Improvement ◽  
Point Source ◽  
River Water ◽  
Constructed Wetlands ◽  
Constructed Wetland ◽  
River Water Quality ◽  
Water Quality Improvement ◽  
Wetland System

The Kaoping River Rail Bridge Constructed Wetland, which was commissioned in 2004, is one of the largest constructed wetlands in Taiwan. This multi-function wetland has been designed for the purposes of non-point source (NPS) pollutant removal, wastewater treatment, wildlife habitat, recreation, and education. The major influents of this wetland came from the local drainage trench containing domestic, agricultural, and industrial wastewaters, and effluents from the wastewater treatment plant of a paper mill. Based on the quarterly investigation results from 2007 to 2009, more than 96% of total coliforms (TC), 48% of biochemical oxygen demand (BOD), and 40% of nutrients (e.g. total nitrogen, total phosphorus) were removed via the constructed wetland system. Thus, the wetland system has a significant effect on water quality improvement and is capable of removing most of the pollutants from the local drainage system before they are discharged into the downgradient water body. Other accomplishments of this constructed wetland system include the following: providing more green areas along the riversides, offering more water assessable eco-ponds and eco-gardens for the public, and rehabilitating the natural ecosystem. The Kaoping River Rail Bridge Constructed Wetland has become one of the most successful multi-function constructed wetlands in Taiwan. The experience obtained from this study will be helpful in designing similar natural treatment systems for river water quality improvement and wastewater treatment.

Application of a constructed wetland for non-point source pollution control

2001 ◽  
Vol 44 (11-12) ◽  
pp. 585-590 ◽  
Author(s):  
C.M. Kao ◽  
J.Y. Wang ◽  
H.Y. Lee ◽  
C.K. Wen
Keyword(s):  
Water Quality ◽  
Point Source ◽  
Constructed Wetlands ◽  
Constructed Wetland ◽  
Pollution Control ◽  
Pistia Stratiotes ◽  
Storm Event ◽  
Untreated Wastewater ◽  
Nps Pollution ◽  
Wetland System

In Taiwan, non-point source (NPS) pollution is one of the major causes of impairment of surface waters. The main objective of this study was to evaluate the efficacy of using constructed wetlands on NPS pollutant removal and water quality improvements. A field-scale constructed wetland system was built inside the campus of National Sun Yat-Sen University (located in southern Taiwan) to remove (1) NPS pollutants due to the stormwater runoff, and (2) part of the untreated wastewater from school drains. The constructed wetland was 40 m (L) × 30 m (W) × 1 m (D), which received approximately 85 m3 per day of untreated wastewater from school drainage pipes. The plants grown on the wetland included floating (Pistia stratiotes L.) and emergent (Phragmites communis L.) species. One major storm event and baseline water quality samples were analyzed during the monitoring period. Analytical results indicate that the constructed wetland removed a significant amount of NPS pollutants and wastewater constituents. More than 88% of nitrogen, 81% of chemical oxygen demand (COD), 85% of heavy metals, and 60% of the total suspended solids (TSS) caused by the storm runoff were removed by the wetland system before discharging. Results from this study may be applied to the design of constructed wetlands for NPS pollution control and water quality improvement.

A simple model to separately simulate point and diffuse nutrient signatures in stream flows

2012 ◽  
Vol 44 (3) ◽  
pp. 538-553 ◽  
Author(s):  
Andrew R. Slaughter ◽  
Denis A. Hughes
Keyword(s):  
Simple Model ◽  
Point Source ◽  
Source Model ◽  
Management Tool ◽  
Nutrient Concentrations ◽  
Statistical Regression ◽  
Management Scenarios ◽  
Diffuse Source ◽  
Wide Range ◽  
Source Component

A simple model has been developed to simulate the relationships between stream flow and point and diffuse nutrient concentrations. The point source component is based on a mechanistic approach (including uncertainty), while the diffuse component relies on a statistical regression model. The model is explained and its application illustrated using flow and nutrient data from the South African Department of Water Affairs national monitoring database. The study sites represent a wide range of different combinations of point and diffuse source contributions to the total nutrient signature. The model has been successfully calibrated against the observed data and the study concludes that the point source component offers opportunities for use as a scenario assessment management tool, largely related to its mechanistic basis. However, further research is required to link the parameters of the diffuse source model to diffuse load causative factors so that the model can be used effectively in un-gauged situations or to assess management scenarios.

XRMF applications of a monolithic, polycapillary, focusing x-ray optic

1996 ◽  
Vol 54 ◽  
pp. 240-241
Author(s):  
D. A. Carpenter ◽  
Ning Gao ◽  
G. J. Havrilla
Keyword(s):  
Trace Elements ◽  
Point Source ◽  
Focal Spot ◽  
Fluorescence Analysis ◽  
X Rays ◽  
Focal Distance ◽  
Spot Diameter ◽  
X Ray ◽  
Focal Spot Diameter

A monolithic, polycapillary, x-ray optic was adapted to a laboratory-based x-ray microprobe to evaluate the potential of the optic for x-ray micro fluorescence analysis. The polycapillary was capable of collecting x-rays over a 6 degree angle from a point source and focusing them to a spot approximately 40 µm diameter. The high intensities expected from this capillary should be useful for determining and mapping minor to trace elements in materials. Fig. 1 shows a sketch of the capillary with important dimensions.The microprobe had previously been used with straight and with tapered monocapillaries. Alignment of the monocapillaries with the focal spot was accomplished by electromagnetically scanning the focal spot over the beveled anode. With the polycapillary it was also necessary to manually adjust the distance between the focal spot and the polycapillary.The focal distance and focal spot diameter of the polycapillary were determined from a series of edge scans.

Sign in / Sign up

Export Citation Format

Share Document