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Pollution: Point Source
Published in Yeqiao Wang, Landscape and Land Capacity, 2020
Mallavarapu Megharaj, Peter Dillon, Ravendra Naidu, Rai Kookana, Ray Correll, W. W. Wenzel
The available remediation technologies may be grouped into two categories: (1) ex situ techniques that require removal of the contaminated soil or groundwater for treatment either on-site or off-site; and (2) in situ techniques that attempt to remediate without excavation of contaminated soils. Generally, in situ techniques are favored over ex situ techniques because of: (1) reduced costs due to elimination or minimization of excavation, transportation to disposal sites, and sometimes treatment itself; (2) reduced health impacts on the public or the workers; and, (3) the potential for remediation of inaccessible sites, e.g., those located at greater depths or under buildings. Although in situ techniques have been successful with organic contaminated sites, the success of in situ strategies with metal contaminants has been limited. Given that organic and inorganic contaminants often occur as a mixture, a combination of more than one strategy is often required to either successfully remediate or manage metal contaminated soils.
Iron and Steel Industry Effluent Treatment Techniques
Published in Mihir Kumar Purkait, Piyal Mondal, Chang-Tang Chang, Treatment of Industrial Effluents, 2019
Mihir Kumar Purkait, Piyal Mondal, Chang-Tang Chang
Bioremediation is a waste management method that uses simple microbes to break down or neutralize waste materials and can be carried out ex situ or in situ. It can be applied to solid, liquid, and gaseous wastes from the steel industry (Jayapriya, 2015). Bioleaching/biosolubilization of heavy metal load-bearing effluents using bacteria or fungi isolated from polluted sources has the potential to remove heavy metals to a higher degree compared with those isolated from nonpolluted virgin sources (Baath, 1989). Reclamation of the huge volume of water used in steel production is a gray area where the application of mixed microbial culture can facilitate better water recycling and recovery. A mixed soil bacterial culture comprising Bacillus, Pseudomonas, Arthrobacter, and Micrococcus has successfully degraded effluents from steel industry with a high BOD and COD of 95% (Krishnaveni et al., 2013). Biosorption is another part of bioremediation, wherein microbes, or a segment of activated biomass, can take up organics as well as inorganics, such as heavy metals, on their surfaces. The microbial cell (solid state) preferentially takes up the materials from effluents (liquid phase) that have a higher affinity for it. Different mechanisms such as extracellular accumulation/precipitation, cell surface sorption/precipitation, and intracellular accumulation govern the location where sorbents will be deposited.
Performance and Potential Application
Published in Donald F. Lowe, Karen L. Duston, Carroll L. Oubre, C. Herb Ward, Douglas A. Hlousek, Thomas A. Phillips, of Firing Range Impact Berms, 2016
Donald F. Lowe, Karen L. Duston, Carroll L. Oubre, C. Herb Ward, Douglas A. Hlousek, Thomas A. Phillips
Soil washing is an ex situ water-based process that separates contaminants from the clean soil matrix. To achieve separation and physical sizing, gravity separation and attrition scrubbing are used. All process water is recycled through a closed-loop treatment system, minimizing water consumption and disposal requirements. Treated soil can be reused on-site, undergo further treatment, or be stabilized, if required, for use as foundation material for subsequent berm reconstruction. The concentrated lead streams recovered during the process are recycled, with the salvage value offsetting a portion of the cleanup cost. Since soil washing is a highly efficient mineral separation process, little, if any, soil ends up in the concentrated lead streams, resulting in premium quality salvageable metals.
Numerical Simulation of Heat Transfer Characteristics of Petroleum Hydrocarbon-Contaminated Soil During Ex-Situ Indirect Thermal Desorption
Published in Soil and Sediment Contamination: An International Journal, 2023
Huili Lin, Zhaodi Jin, Guangxue Zhang, Rengang Liang, Shuli Zhang, Qun Yu
Among the remediation technologies currently developed and practiced for petroleum hydrocarbon contaminated soil, ex-situ thermal desorption technology is used to excavate contaminated soil from the pot, and selectively promote the gasification and volatilization of pollutants from soil particles by heating method (Ding et al. 2019; McAlexander, Krembs, and Cardeñosa Mendoza 2015). This method has controllable treatment effect, short remediation period, strong applicability and low environmental risk which have been recommended by the United States Environmental Protection Agency in 1985 and was adopted in 77 of 571 ex-situ soil remediation projects in the United States from 1982 to 2014, accounting for 13.5% of the total number (Shen et al. 2019). In addition, direct and indirect thermal desorption can be classified according to the contact forms between heat source and soil. Generally, indirect thermal desorption technique is more rapid, energy saving and CO2-friendly able to mobilize petroleum hydrocarbons into gaseous flow with less flue gas emission and recover condensable compounds as process mediums (Kuppusamy et al. 2016; O’Brien et al. 2018; Vidonish et al. 2016).
Soil and groundwater remediation proposal for hydrocarbons in a tropical aquifer
Published in Journal of Applied Water Engineering and Research, 2022
Adriana Márquez, Estafania Freytez, Julio Maldonado, Edilberto Guevara, Sergio Pérez, Eduardo Buroz
The remediation of soil and groundwater pollutants, whether by physical, chemical, biological (bioremediation) means, or any combination thereof, are the only options to eliminate them. In particular, bioremediation involves the use of microorganisms to degrade hazardous organic constituents to harmless substances, such as carbon dioxide and water (Wilson and Jones 1993). The bioremediation can be carried out ex situ or in situ, depending on several factors including, but not limited to, cost, site characteristics, type, and concentration of pollutants (Azubuike et al. 2016). Ex-situ and in-situ techniques offer specific benefits and costs. Despite the high cost, ex situ treatment usually demands less time to reach efficient contaminant cleanup, is easily controlled, and achieves greater uniformity (Kuppusamy et al. 2016).
Biodegradation and detoxification study of triphenylmethane dye (Brilliant green) in a recirculating packed-bed bioreactor by bacterial consortium
Published in Environmental Technology, 2022
Himanshu Tiwari, Ravi Kumar Sonwani, Ram Sharan Singh
In the last few decades, several conventional physicochemical and biological methods have been used for the abatement of synthetic dyes. In physicochemical methods, ozonation, photo-catalytic degradation, adsorption, electrochemical oxidation, UV-Fenton oxidation, coagulation/flocculation, membrane separation, sonophotocatalytic degradation and ion-exchange techniques have been employed to treat the wastewater containing dyes [8,9]. The limitations, such as toxic sludge generation, harmful byproducts, operational difficulty, and high cost are associated with physicochemical methods [10]. However, biological methods are reported as cost-effective and environmentally friendly methods to treat synthetic dyes [11]. Nowadays, Biological treatment (i.e. Bioremediation) emerges as a promising technological tool to treat the dyes containing wastewater. Microorganisms such as Aeromonas hydrophila, Klebsiella quasipneumoniae, Pseudomonas aeruginosa, Aeromonas sp., Shewanella oneidensis, and Bacillus sp., etc. have shown promising results toward biodegradation of textile dyes [12]. The bioremediation technique deals with the activity and growth of microbes and their efficacy towards waste mineralisation, either in situ or ex-situ, under suitable environmental conditions. It is associated with several advantages such as complete mineralisation of pollutants, less secondary toxic waste generation, energy efficiency, and eco-friendly compared to the conventional physicochemical methods.