Screening the retention of thirteen pesticides in a small constructed wetland

2003 ◽  
Vol 48 (5) ◽  
pp. 267-274 ◽  
Author(s):  
B.C. Braskerud ◽  
K. Haarstad
Keyword(s):  
Organic Matter ◽  
Redox Potential ◽  
Constructed Wetlands ◽  
Constructed Wetland ◽  
Water Purification ◽  
Aquatic Life ◽  
Retention Factors ◽  
Relative Retention ◽  
Hydraulic Load ◽  
High Redox Potential

When pesticides are used in arable watersheds, residues are usually found in the recipients. However, small constructed wetlands (CWs) in first and second order streams can reduce the loss of pesticides, since water purification processes are stimulated. This paper presents the results of adding 13 pesticides to a CW in Norway. The relative retention increased between 0 and 67% for the pesticides fluroxypyr, bentazone, dicamba, mecoprop, propiconazole, MCPA, dichlorprop, linuron, fenpropimorph, metalaxyl, metribuzin, metamitron and propachlor. In many cases, the CW reduced the peak concentrations to values regarded as non-toxic for aquatic life, even though the wetland covered less than 0.4% of the watershed surface area, and the average hydraulic load often was above 0.8 m d-1. Possible retention factors were adsorption to soil particles and organic matter, sedimentation of particles, low or high redox-potential, and biodegradation of nitrogen-rich pesticides. However, the retention processes are complex, and are not fully understood.

Enhancement of the performance of constructed wetlands for wastewater treatment in winter: the effect of Tubifex tubifex

RSC Advances ◽  
2016 ◽  
Vol 6 (41) ◽  
pp. 34841-34848 ◽  
Author(s):  
Yan Kang ◽  
Jian Zhang ◽  
Huijun Xie ◽  
Zizhang Guo ◽  
Pengfei Li ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Constructed Wetlands ◽  
Constructed Wetland ◽  
Water Purification ◽  
Tubifex Tubifex ◽  
Batch Systems ◽  
Potential Use

An improved constructed wetland (CW) with the addition ofTubifex tubifexin winter was studied in laboratory batch systems. The outcomes of this study indicate that the potential use ofTubifex tubifexcould improve the ecosystem and water purification by CWs in winter.

scholarly journals Study on the Decontamination Effect of Biochar-Constructed Wetland under Different Hydraulic Conditions

Water ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 893
Author(s):  
Chuanjie Xing ◽  
Xiangxi Xu ◽  
Zhenghe Xu ◽  
Rongzhen Wang ◽  
Lirong Xu
Keyword(s):  
Chemical Oxygen Demand ◽  
Constructed Wetlands ◽  
Total Nitrogen ◽  
Total Phosphorus ◽  
Constructed Wetland ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Removal Rates ◽  
Hydraulic Conditions ◽  
Hydraulic Load

To explore the purification effect of biochar-constructed wetlands on rural domestic sewage, six types of biochar-constructed wetlands were constructed for experiments. Under different hydraulic conditions, the removal effects of each biochar-constructed wetland on chemical oxygen demand, ammonia nitrogen, total nitrogen, and total phosphorus in sewage were analyzed. The results showed that the removal rates of the four types of pollutants in each biochar-constructed wetland first increased and then decreased with the increase in hydraulic retention time, and the optimal hydraulic retention time range was 36–48 h. The highest removal rates of chemical oxygen demand, ammonia nitrogen, total nitrogen, and total phosphorus in the wetland were 97.34 ± 0.84%, 95.44 ± 1.29%, 98.95 ± 0.52%, and 97.78 ± 0.91%, respectively. The chemical oxygen demand (COD) removal rate of each biochar-constructed wetland increased first, then decreased with the increase in hydraulic load, and the optimal hydraulic load was 10 cm/d. The removal efficiency of ammonia nitrogen, total nitrogen, and total phosphorus of each biochar-constructed wetland gradually weakened with the increase in hydraulic load, and the optimal hydraulic load range was between 5 and 10 cm/d. Under these conditions, the highest removal rates of chemical oxygen demand, ammonia nitrogen, total nitrogen, and total phosphorus in the wetland were 92.15 ± 2.39%, 98.32 ± 0.48%, 96.69 ± 1.26%, and 92.62 ± 2.92%, respectively. Coconut shell and shell-constructed wetlands with the highest proportion of biochar in the matrix have the best removal effect on pollutants under different hydraulic conditions, and the wastewater purification effect is stronger, indicating that the addition of biochar is helpful for the removal of pollutants in constructed wetlands.

scholarly journals Horizontal-flow (HF) constructed wetlands for winery wastewater treatment: A review

2021 ◽  
Vol 245 ◽  
pp. 02022
Author(s):  
Yuhan Miao
Keyword(s):  
Organic Matter ◽  
Wastewater Treatment ◽  
Energy Saving ◽  
Constructed Wetlands ◽  
Constructed Wetland ◽  
Low Cost ◽  
Horizontal Flow ◽  
Agricultural Activities ◽  
Winery Wastewater

The winery wastewater starts to become a threaten to environment and ecosystem. Because constructed wetland has advantages of low cost, low maintaining fee and energy saving, there are more researchers use this technology to purify the winery wastewater. In this article, the horizontal flow constructed wetland will be mainly focused. By using this method, the N, P, organic matter, and other pollutants will be efficiently removed and reused in other phase, such like agricultural activities. The constructed wetland can also supply itself. By transfer the nutrition matter from wastewater and support its’ own plants’ energy.

scholarly journals Hybrid Constructed Wetland to Improve Organic Matter and Nutrient Removal

Water ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 2023
Author(s):  
M. I. Fernandez-Fernandez ◽  
P. T. Martín de la Vega ◽  
M. A. Jaramillo-Morán ◽  
M. Garrido
Keyword(s):  
Organic Matter ◽  
Constructed Wetlands ◽  
Constructed Wetland ◽  
Small Businesses ◽  
Primary Treatment ◽  
Small Towns ◽  
Vertical Flow ◽  
Urban Agglomerations ◽  
Vertical Flow Constructed Wetlands ◽  
Agricultural Industries

Constructed wetlands are one of the best technologies for wastewater treatment in small towns, small businesses or farms and/or livestock breeding. In this work, a wastewater depuration ecological system implemented in a hybrid constructed wetland to remove nutrients and organic matter from small urban agglomerations is studied. It comprises two processing stages: a primary treatment carried out in two hydrolytic up-flow sludge bed digesters working in parallel and a secondary one made up of two vertical flow constructed wetlands, which are alternatively used, followed by a horizontal flow constructed wetland. An internal recirculation system connects the output of the vertical flow constructed wetlands to the input of the hydrolytic up-flow sludge bed digesters with the aim of promoting the nitrification-denitrification process. High nutrients and organic matter removal efficiencies were observed when treating highly polluted wastewater from an animal farm. Therefore, this ecological depuration system, designed with an internal recirculation to enhance nitrogen reduction, may be considered an efficient alternative to treat wastewater from small urban agglomerations and diffuse contamination from agricultural industries and livestock farms polluting surface waters with nitrates, which may cause serious environmental problems, such as eutrophication.

A Review of Research on Substrate Materials for Constructed Wetlands

2018 ◽  
Vol 913 ◽  
pp. 917-929 ◽  
Author(s):  
Han Xi Wang ◽  
Jian Ling Xu ◽  
Lian Xi Sheng ◽  
Xue Jun Liu
Keyword(s):  
Constructed Wetlands ◽  
Constructed Wetland ◽  
Removal Rate ◽  
Meta Analysis ◽  
Substrate Material ◽  
Nitrogen And Phosphorus ◽  
Literature Research ◽  
Future Studies ◽  
Hydraulic Load ◽  
Potential Improvement

Based on the improvements in the decontamination ability and decontamination range of constructed wetlands, this study of constructed wetland substrates was carried out using literature research and comparative meta-analysis. The results show that, for static adsorption, the absorption levels of nitrogen and phosphorus in a given constructed wetland are different. As for hydraulic load, the average removal rate of total nitrogen in wastewater is less than 50%. Compared with single substrates, a combination of substrates is typically superior in terms of the removal rate of sewage pollutants. Adsorption is the key in removing pollutants in constructed wetlands, and modification of the wetland materials is an effective way to improve the decontamination ability of the substrate material. At present, there are areas of potential improvement in the research on the development of new wetland materials for the study of pollutant characteristics, as well as a dearth of modification methods for single and reclaimable wetland substrates in constructed wetlands. These issues should be taken into account in the future studies on constructed wetland materials.

Cold-climate constructed wetlands

1995 ◽  
Vol 32 (3) ◽  
pp. 95-101 ◽  
Author(s):  
T. Mæhlum ◽  
P. D. Jenssen ◽  
W. S. Warner
Keyword(s):  
Organic Matter ◽  
Adsorption Capacity ◽  
Constructed Wetlands ◽  
Constructed Wetland ◽  
Domestic Wastewater ◽  
Cold Climate ◽  
Cold Climates ◽  
Phosphorus Adsorption ◽  
Design Considerations ◽  
Northern Latitudes

This paper outlines design considerations for constructed wetlands with horizontal subsurface flow treating domestic wastewater in cold climates of northern latitudes. Particular attention is devoted to the use of a filter medium with high phosphorus adsorption capacity. Experience from two Norwegian multistage systems consisting of an aerobic pretreatment step followed by constructed wetland units indicates purification processes are nearly the same during winter and summer seasons, with quite high removal of organic matter (COD, BOD), phosphorus and nitrogen.

Enhancement of nitrogen removal in subsurface flow constructed wetlands employing a 2-stage configuration, an unsaturated zone, and recirculation

1995 ◽  
Vol 32 (3) ◽  
pp. 59-67 ◽  
Author(s):  
Kevin D. White
Keyword(s):  
Constructed Wetlands ◽  
Nitrogen Removal ◽  
Constructed Wetland ◽  
Subsurface Flow ◽  
Great Promise ◽  
Effluent Recirculation ◽  
Wetland Treatment ◽  
Subsurface Flow Constructed Wetlands ◽  
Inlet Zone ◽  
Bod Removal

Constructed wetland technology is currently evolving into an acceptable, economically competitive alternative for many wastewater treatment applications. Although showing great promise for removing carbonaceous materials from wastewater, wetland systems have not been as successful at nitrification. This is primarily due to oxygen limitations. Nitrification does occur in conventional wetland treatment systems, but typically requires long hydraulic retention times. This paper describes a study that first evaluated the capability of subsurface flow constructed wetlands to treat a high strength seafood processor wastewater and then evaluated passive aeration configurations and effluent recirculation with respect to nitrogen treatment efficiency. The first stage of a 2-stage wetland treatment system exhibited a relatively short hydraulic retention time and was designed for BOD removal only. The second stage wetland employed an unsaturated inlet zone and effluent recirculation to enhance nitrification. Results indicate that organic loading, and thus BOD removal, in the first stage wetland is key to optimal nitrification. Passive aeration through an unsaturated inlet zone and recirculation achieved up to 65-70 per cent ammonia nitrogen removal at hydraulic retention times of about 3.5 days. Inlet zone configuration and effluent recirculation is shown to enhance the nitrogen removal capability of constructed wetland treatment systems.

Using Decomposition Kinetics to Model the Removal of Mine Water Pollutants in Constructed Wetlands

1994 ◽  
Vol 29 (4) ◽  
pp. 219-226 ◽  
Author(s):  
William J. Tarutis ◽  
Richard F. Unz
Keyword(s):  
Organic Matter ◽  
Constructed Wetlands ◽  
Mine Drainage ◽  
Term Treatment ◽  
Decomposition Kinetics ◽  
Dry Density ◽  
Organic Matter Concentration ◽  
Long Term Treatment ◽  
Input Variables ◽  
Reaction Stoichiometry

Although numerous mathematical models have been used to describe decomposition, few, if any, have been used to model the removal of pollutants in constructed wetlands. A steady-state model based on decomposition kinetics and reaction stoichiometry has been developed which simulates the removal of ferrous iron entering wetlands constructed for mine drainage treatment. Input variables for the model include organic matter concentration, reaction rate coefficient, porosity and dry density, and hydraulic detention time. Application of the model assumes complete anaerobic conditions within the entire substrate profile, constant temperature, no additional organic matter input, and subsurface flow only. For these ideal conditions, model simulations indicate that wetlands constructed with readily decomposable substrates rich in organic carbon are initially capable of removing far greater amounts of iron than wetlands built with less biodegradable substrates. However, after three to five years of operation this difference becomes negligible. For acceptable long-term treatment performance, therefore, periodic additions of decomposable organic matter will be required.

A few key residues determine the high redox potential shift in azurin mutants

2015 ◽  
Vol 13 (45) ◽  
pp. 11003-11013 ◽  
Author(s):  
Laura Zanetti-Polzi ◽  
Carlo A. Bortolotti ◽  
Isabella Daidone ◽  
Massimiliano Aschi ◽  
Andrea Amadei ◽  
...  
Keyword(s):  
Redox Potential ◽  
Potential Shift ◽  
Key Residues ◽  
High Redox Potential

The changes in the redox potential of Azurin upon mutation stem from the effects of a few key residues, including non-mutated ones, rather than being the result of a generalized rearrangement.

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