An Overview of Constructed Wetlands as Alternatives to Conventional Waste Treatment Systems

1993 ◽  
Vol 28 (3) ◽  
pp. 529-548 ◽  
Author(s):  
Hugh Hamilton ◽  
Peter G. Nix ◽  
André Sobolewski
Keyword(s):  
Constructed Wetlands ◽  
Organic Contaminants ◽  
Waste Treatment ◽  
Low Cost ◽  
Ecological Resilience ◽  
Background Information ◽  
Chemical Pollution ◽  
Organic Chemical ◽  
Attractive Alternative ◽  
Sediment Layer

Abstract Constructed wetlands are an attractive alternative to conventional wastewater treatment under certain conditions. This review presents background information on wetland treatment and wetland design, and outlines the potential for wetlands to treat water contaminated with organic compounds including hydrocarbons. The major mechanisms that reduce contaminant concentrations in wetlands are sedimentation, filtration, chemical precipitation, microbial interaction and plant uptake. The presence of bacteria in “biofilms” on the enormous plant and detrital surface area in wetlands is fundamental to their ability to degrade complex organic contaminants. There are few examples in the literature of wetlands being used to control organic chemical pollution. However, the very high level of biochemical activity in the water column and upper sediment layer in wetlands, combined with a high degree of ecological resilience, suggests that wetlands can be an attractive low cost, low energy, low maintenance alternative to conventional treatment methods.

scholarly journals “Green” Water Treatment for the Green Industries: Opportunities for Biofiltration of Greenhouse and Nursery Irrigation Water and Runoff with Constructed Wetlands

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 690c-690
Author(s):  
R.D. Berghage
Keyword(s):  
Water Treatment ◽  
Constructed Wetlands ◽  
Irrigation Water ◽  
Plant Pathogens ◽  
Irrigation System ◽  
Low Cost ◽  
Agricultural Waste ◽  
Green Water ◽  
Organic Chemical ◽  
Primary Concern

Constructed wetland biofilters have been widely used in recent years to provide secondary or tertiary water treatment, effectively reducing BOD, TSS, nitrate and ammonium, and some organic pollutants from municipal, industrial, and agricultural waste sources. The greenhouse and nursery industries, like all agricultural enterprises, have found themselves under increasing pressure to reduce or eliminate discharge of contaminated wastewater. In response, many greenhouse and nursery operators have installed, and are using, a variety of runoff containment and recirculating irrigation systems. While effective in reducing or eliminating wastewater discharge, these systems can become contaminated themselves and require treatment of the water before it can be reused in the irrigation system. Further, if the water should become contaminated and unusable, environmental discharge of this spent water from a recirculating irrigation system is perhaps even more problematic than simply allowing the excess irrigation water to be dumped in the first place. Potential contaminants in a recirculating irrigation system could include pesticide and other organic residues, excess fertilizer and non-fertilizer salts, and plant pathogens. The primary concern in greenhouse and nursery discharge wastewater is usually fertilizer salts, although pesticide and other organic chemical residues may also be of concern. Biological filtration using constructed wetlands may be a simple low-cost method for greenhouses and nurseries to treat these contaminants.

Organic chemical devulcanization of rubber vulcanizates in supercritical carbon dioxide and associated less eco-unfriendly approaches: A review

2021 ◽  
pp. 0734242X2110085
Author(s):  
Jabulani I Gumede ◽  
Buyiswa G Hlangothi ◽  
Chris D Woolard ◽  
Shanganyane P Hlangothi
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Negative Impact ◽  
Raw Materials ◽  
Chemical Components ◽  
Organic Chemical ◽  
Attractive Alternative ◽  
Special Focus ◽  
Waste Tyres ◽  
Supercritical Carbon

There is a growing need to recover raw materials from waste due to increasing environmental concerns and the widely adopted transition to circular economy. For waste tyres, it is necessary to continuously develop methods and processes that can devulcanize rubber vulcanizates into rubber products with qualities and properties that can closely match those of the virgin rubber. Currently, the most common, due to its efficiency and perceived eco-friendliness in recovering raw rubber from waste rubbers, such as tyres, is devulcanization in supercritical carbon dioxide (scCO2) using commercial and typical devulcanizing agents. The scCO2 has been generally accepted as an attractive alternative to the traditional liquid-based devulcanization media because of the resultant devulcanized rubber has relatively better quality than other processes. For instance, when scCO2 is employed to recover rubber from waste tyres (e.g. truck tyres) and the recovered rubber is blended with virgin natural rubber (NR) in various compositions, the curing and mechanical properties of the blends closely match those of virgin NR. The atmospheric toxicity and cost of the commonly used devulcanization materials like chemical agents, oils and solvents have enabled a shift towards utilization of greener (mainly organic) and readily available devulcanization chemical components. This literature review paper discusses the approaches, which have less negative impact on the environment, in chemical devulcanization of rubber vulcanizates. A special focus has been on thermo-chemical devulcanization of waste tyres in scCO2 using common organic devulcanizing agents.

scholarly journals Light Cross-Linkable Marine Collagen for Coaxial Printing of a 3D Model of Neuromuscular Junction Formation

Biomedicines ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 16
Author(s):  
Borja Sanz ◽  
Ane Albillos Sanchez ◽  
Bonnie Tangey ◽  
Kerry Gilmore ◽  
Zhilian Yue ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Neuromuscular Junction ◽  
Disease Transmission ◽  
Low Cost ◽  
Attractive Alternative ◽  
Waste Products ◽  
Environmentally Sustainable ◽  
Zoonotic Disease Transmission ◽  
And Migration

Collagen is a major component of the extracellular matrix (ECM) that modulates cell adhesion, growth, and migration, and has been utilised in tissue engineering applications. However, the common terrestrial sources of collagen carry the risk of zoonotic disease transmission and there are religious barriers to the use of bovine and porcine products in many cultures. Marine based collagens offer an attractive alternative and have so far been under-utilized for use as biomaterials for tissue engineering. Marine collagen can be extracted from fish waste products, therefore industry by-products offer an economical and environmentally sustainable source of collagen. In a handful of studies, marine collagen has successfully been methacrylated to form collagen methacrylate (ColMA). Our work included the extraction, characterization and methacrylation of Red Snapper collagen, optimisation of conditions for neural cell seeding and encapsulation using the unmodified collagen, thermally cross-linked, and the methacrylated collagen with UV-induced cross-linking. Finally, the 3D co-axial printing of neural and skeletal muscle cell cultures as a model for neuromuscular junction (NMJ) formation was investigated. Overall, the results of this study show great potential for a novel NMJ in vitro 3D bioprinted model that, with further development, could provide a low-cost, customizable, scalable and quick-to-print platform for drug screening and to study neuromuscular junction physiology and pathogenesis.

scholarly journals Mechanisms and adsorption capacities of biochar for the removal of organic and inorganic pollutants from industrial wastewater

2020 ◽  
Author(s):  
T. G. Ambaye ◽  
M. Vaccari ◽  
E. D. van Hullebusch ◽  
A. Amrane ◽  
S. Rtimi
Keyword(s):  
Organic Contaminants ◽  
Pyrolysis Temperature ◽  
Low Cost ◽  
Industrial Effluents ◽  
Economic Benefits ◽  
Inorganic Pollutants ◽  
Solution Ph ◽  
Adsorption Mechanisms ◽  
Adsorption Capacities ◽  
Temperature Solution

AbstractCurrently, due to the rapid growth of urbanization and industrialization in developing countries, a large volume of wastewater is produced from industries that contain chemicals generating high environmental risks affecting human health and the economy if not treated properly. Consequently, the development of a sustainable low-cost wastewater treatment approach has attracted more attention of policymakers and scientists. The present review highlights the recent applications of biochar in removing organic and inorganic pollutants present in industrial effluents. The recent modes of preparation, physicochemical properties and adsorption mechanisms of biochar in removing organic and inorganic industrial pollutants are also reviewed comprehensively. Biochar showed high adsorption of industrial dyes up to 80%. It also discusses the recent application and mechanism of biochar-supported photocatalytic materials for the degradation of organic contaminants in wastewater. We reviewed also the possible optimizations (such as the pyrolysis temperature, solution pH) allowing the increase of the adsorption capabilities of biochar leading to organic contaminants removal. Besides, increasing the pyrolysis temperature of the biochar was seen to lead to an increase in its surface area, while it decreases their amount of oxygen-containing functional groups, consequently leading to a decrease in the adsorption of metal (loid) ions present in the medium. Finally, the review suggests that more research should be carried out to optimize the main parameters involved in biochar production and its regeneration methods. Future efforts should be also carried out towards process engineering to improve its adsorption capacity to increase the economic benefits of its implementation.

scholarly journals Adjusted Unit Value Transfer as a Tool for Raising Awareness on Ecosystem Services Provided by Constructed Wetlands for Water Pollution Control: An Italian Case Study

2021 ◽  
Vol 18 (4) ◽  
pp. 1531
Author(s):  
Anacleto Rizzo ◽  
Giulio Conte ◽  
Fabio Masi
Keyword(s):  
Water Pollution ◽  
Ecosystem Services ◽  
Constructed Wetlands ◽  
Pollution Control ◽  
Green Infrastructure ◽  
Low Cost ◽  
Water Pollution Control ◽  
Italian Case ◽  
Value Transfer ◽  
Unit Value

Constructed wetlands (CWs) are nature-based solutions (NBS) for water pollution control that can also be designed to be multipurpose in terms of additional ecosystem services (ESs), such as biodiversity support and social benefits. Awareness about additional ESs of CWs can be raised with value transfer (VT) methods for ESs monetization, in particular, the simplified adjusted unit VT method. A multi-criteria analysis (MCA) was performed to compare grey and green infrastructure alternatives for the management of a combined sewer overflow in the Buccinasco town (Italy), in which the criteria related to ESs were monetized with an adjusted VT method (B£ST software). The results highlighted the potential interest in the implementation of the green infrastructure in a new urban park, due to the activation of additional ESs of interest, such as health and recreational aspects. The results were also confirmed by a sensitivity analysis, which simulated the variation of preferences among different stakeholder groups (e.g., citizens, environmentalists). In conclusion, this work provided a transparent methodology to support decisions regarding green and grey infrastructure, allowing to evaluate additional ESs from the beginning of the decision stage with low cost and efforts.

Mocvd SrS:Ce for Applications in Electroluminescent Devices

1997 ◽  
Vol 471 ◽  
Author(s):  
D. Endisch ◽  
K. Barth ◽  
J. Lau ◽  
G. Peterson ◽  
A. E. Kaloyeros ◽  
...  
Keyword(s):  
Process Development ◽  
Process Integration ◽  
Low Cost ◽  
Chemical Vapor ◽  
High Growth ◽  
Film Structure ◽  
High Growth Rate ◽  
Organic Chemical ◽  
Glass Substrates ◽  
Full Color

ABSTRACTSrS:Ce is an important material for full color electroluminescent (EL) flat panel displays. Using a combination of SrS:Ce/ZnS:Mn and appropriate color filters high quality full color displays have been demonstrated [1]. Major issues for commercially viable process integration of SrS:Ce are the combination of high luminance, high growth rate, and process temperatures below 600°C for compatibility with low cost glass substrates. This work describes the process development and optimization of metal-organic chemical vapor deposition (MOCVD) of SrS:Ce. MOCVD is a promising candidate for deposition of SrS:Ce because it can provide the required growth rates and allows control of crystal structure and stoichiometry. Growth of SrS:Ce was performed in the temperature range from 400°C to 530°C using Sr(tmhd)2, Ce(tmhd)4, and H2S as precursors. The structure of the SrS:Ce was found to be strongly dependent on the H2S flow. A brightness of 15 fL and an efficiency of 0.22 lm/W has been achieved (40 V above threshold voltage, 60 Hz AC). Film analysis included Rutherford backscattering (RBS), X-ray diffraction (XRD), atomic force microscopy (AFM), and EL measurements. Results on the correlation between process parameters, film structure, grain size and EL performance will be presented.

NUMERICAL ANALYSIS OF FLOW BEHAVIOR IN GAS-LIQUID CYLINDRICAL CYCLONE (GLCC©*) SEPARATORS WITH INLET DESIGN MODIFICATIONS

2021 ◽  
pp. 1-27
Author(s):  
Srinivas Swaroop Kolla ◽  
Ram S. Mohan ◽  
Ovadia Shoham
Keyword(s):  
Numerical Study ◽  
Flow Behavior ◽  
Low Cost ◽  
Field Application ◽  
Attractive Alternative ◽  
Inlet Section ◽  
Wide Range ◽  
Cylindrical Cyclone ◽  
Light Oil ◽  
Section Design

Abstract The Gas-Liquid Cylindrical Cyclone (GLCC©*) is a simple, compact and low-cost separator, which provides an economically attractive alternative to conventional gravity-based separators over a wide range of applications. More than 6,500 GLCC©'s have been installed in the field to date around the world over the past 2 decades. The GLCC© inlet section design is a key parameter, which is crucial for its performance and proper operation. The flow behavior in the GLCC© body is highly dependent on the fluid velocities generated at the reduced area nozzle inlet. An earlier study (Kolla et al. [1]) recommended design modifications to the inlet section, based on safety and structural robustness. It is important to ensure that these proposed configuration modifications do not adversely affect the flow behavior at the inlet and the overall performance of the GLCC©. This paper presents a numerical study utilizing specific GLCC© field application working under 3 different case studies representing the flow entering the GLCC, separating light oil, steam flooded wells in Minas, Indonesia. Commercially available Computational Fluid Dynamics (CFD) software is utilized to analyze the hydrodynamics of flow with the proposed modifications of the inlet section for GLCC© field applications.

Near-Infrared Spectroscopy with a Dispersive Waveguide Device

1997 ◽  
Vol 51 (6) ◽  
pp. 880-882 ◽  
Author(s):  
Brian R. Stallard ◽  
Robert K. Rowe ◽  
Arnold J. Howard ◽  
G. Ronald Hadley ◽  
Gregory A. Vawter ◽  
...  
Keyword(s):  
Near Infrared ◽  
Low Cost ◽  
Ion Beam ◽  
Chemical Vapor ◽  
Discrete Source ◽  
Ethanol Solution ◽  
Organic Chemical ◽  
Ion Beam Etching ◽  
Spectral Dispersion ◽  
Metal Organic

Miniature, low-cost sensors are in demand for a variety of applications in industry, medicine, and environmental sciences. As a first step in developing such a sensor, we have etched a grating into a GaAs rib waveguide to serve as a wavelength-dispersive element. The device was fabricated with the techniques of metal-organic chemical vapor deposition, electron-beam lithography, optical lithography, and reactive ion-beam etching. While full integration is the eventual goal of this work, for the present, a functional spectrometer was constructed with the addition of a discrete source, sample cell, lenses, and detector. The waveguide spectrometer has a spectral resolution of 7.5 nm and a spectral dispersion of 0.11°/ nm. As presently configured, it functions in the spectral range of 1500 to 1600 nm. A demonstration of the analytical capability of the waveguide spectrometer is presented. The problem posed is the determination of diethanol amine in an ethanol solution (about 10 to 100 g/L). This procedure involves the detection of the first overtone of the NH stretch at 1545 nm in a moderately absorbing solvent background. The standard error of prediction for the determination was 5.4 g/L.

Heavy Fluoride Glasses as an Alternative to Crystals in High Energy Physics Calorimetry

1994 ◽  
Vol 348 ◽  
Author(s):  
I. Dafinei ◽  
E. Auffray ◽  
P. Lecoq ◽  
M. Schneegans
Keyword(s):  
High Energy Physics ◽  
Low Cost ◽  
High Energy ◽  
Attractive Alternative ◽  
Close Collaboration ◽  
Fluoride Glasses ◽  
Different Types ◽  
Electromagnetic Calorimeters ◽  
Physics Experiments ◽  
Energy Physics

ABSTRACTIn the quest for low cost scintillators to equip the very large electromagnetic calorimeters for future High Energy Physics experiments, scintillating glasses can offer an attractive alternative to crystals. The expected production price is indeed supposed to be reduced as compared to crystals, especially for very large volumes. An intense R&D effort has been made by the Crystal Clear collaboration to develop heavy scintillating fluoride glasses in close collaboration with the industry. Results will be shown on the fluorescence and scintillation properties as well as on the radiation resistance of different types of fluoride glasses. Ideas about possible improvement of present performances will also be given.

Ecological Waste Treatment and Utilization Systems on Low-Cost, Energy-Saving/Generating and Resources Recoverable Technology for Water Pollution Control in China

1991 ◽  
Vol 24 (5) ◽  
pp. 9-19 ◽  
Author(s):  
Baozhen Wang
Keyword(s):  
Pollution Control ◽  
Rural Areas ◽  
Waste Treatment ◽  
Low Cost ◽  
Fish Ponds ◽  
Receiving Waters ◽  
Recoverable Resources ◽  
Urban And Rural Areas ◽  
Rice Fish ◽  
Utilization Of Wastes

Various ecological waste treatment and utilization systems (EWTUS) available in urban and rural areas in China are described, among which are land treatment and utilization systems (LTUS), eco-pond systems mainly consisting of macrohydrophytes-growing ponds, fish ponds and duck/geese ponds, and comprehensive circulation eco–systems for the treatment and utilization of wastes in rural areas, such as semi–closed eco–system in fish ponds, “rice–fish” and “rice–azolla–fish” symbiotic systems, recycling eco–systems with methane-generating digesters as central link, and comprehensive recycling eco–systems with digesters and eco–ponds as central link. In the various EWTUS, the sewage and wastewaters and other wastes are utilized and converted into various forms of recoverable resources and/or energy, while they are being purified to good quality effluents, meeting their respective discharge standards, and hence acceptable to receiving waters.

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