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Kalmykova, T. D., and V. V. Kuznetsov. "Kineticand thermodynamic aspects of flotation beneficiation of polymetallic raw materials." E3S Web of Conferences 266 (2021): 02015. http://dx.doi.org/10.1051/e3sconf/202126602015.
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The article presents the results of the development of a method-ological approach to the analysis of kinetic and thermodynamic parameters for improving the efficiency of flotation processing of polymetallic raw materials.The kinetic dependences of flotation, the hydrophobizing ability of butyl potassium xanthogenate, and the effect of reagents on preliminary mechanical activation were studied, and flotation modeling with and with-out an oxidizer was performed. The best results of convergence with the kinetic dependences of flotation are shown by the Beloglazov equation, the Kelsall and the modified Kelsall models. Technological indicators of sul-fide flotation in the presence of oxidants are higher, which can be ex-plained by the intensive oxidation of the formed transient ions on the sur-face of minerals, which contributes to the alignment of the flotation properties of the surface.It is possible to integrate the proposed research methods into technological schemes in order to optimize technological in-dicators and increase profits.
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Deo, Namita, and K. A. Natarajan. "Biodegradation of some organic flotation reagents bybacillus polymyxa." Bioremediation Journal 2, no. 3-4 (December 1998): 205–14. http://dx.doi.org/10.1080/10889869809380378.
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Deo, Namita, and K. A. Natarajan. "Biodegradation of Some Organic Flotation Reagents by Bacillus polymyxa." Bioremediation Journal 2, no. 3 (December 1, 1998): 205–14. http://dx.doi.org/10.1080/10889869891214321.
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Sablin, A. V. "Intensifying coal flotation by means of oxyethylated reagents." Coke and Chemistry 51, no. 8 (August 2008): 297–301. http://dx.doi.org/10.3103/s1068364x08080024.
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Petukhov, V. N., A. V. Sablin, L. I. Kovaleva, and A. A. Yunash. "Intensification of coal flotation by means of oxyethylated reagents." Coke and Chemistry 51, no. 3 (March 2008): 73–76. http://dx.doi.org/10.3103/s1068364x08030010.
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Derhy, Manar, Yassine Taha, Rachid Hakkou, and Mostafa Benzaazoua. "Review of the Main Factors Affecting the Flotation of Phosphate Ores." Minerals 10, no. 12 (December 10, 2020): 1109. http://dx.doi.org/10.3390/min10121109.
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The way to successfully upgrade a phosphate ore is based on the full understanding of its mineralogy, minerals surface properties, minerals distribution and liberation. The conception of a treatment process consists of choosing the proper operations with an adequate succession depending on the ore properties. Usually, froth flotation takes place in phosphate enrichment processes, since it is cheap, convenient, and well developed. Nevertheless, it is a complex technique as it depends on the mineral’s superficial properties in aqueous solutions. Aspects such as wettability, surface charge, zeta potential, and the solubility of minerals play a basic role in defining the flotation conditions. These aspects range from the reagents type and dosage to the pH of the pulp. Other variables namely particles size, froth stability, and bubbles size play critical roles during the treatment, as well. The overall aim is to control the selectivity and recovery of the process. The following review is an attempt to add to previous works gathering phosphate froth flotation data. In that sense, the relevant parameters of phosphate ores flotation are discussed while focusing on apatite, calcite, dolomite, and quartz as main constituent minerals.
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IOANA CORINA, MOGA, MATACHE MIHAI GABRIEL, and COVALIU ILEANA CRISTINA. "Advanced wastewater treatment stage for textile industry." Industria Textila 69, no. 06 (January 1, 2019): 478–82. http://dx.doi.org/10.35530/it.069.06.1501.
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Dissolved air flotation represents an important stage for wastewater treatment and was used during the last sixty years for different pollutants such as: suspended solids, greases, oils etc. Nowadays, the dissolved air systems are generally applied in industrial wastewater treatment plants, where the amount of pollutants is above the average (textile and leather industry). The research team members developed an innovative DAF unit and realized a laboratory demonstrator (figure 1). The laboratory installation was tested and the efficiency of wastewater treatment was demonstrated. The latest researches proved that flotation reagents have an essential role in the removal of different pollutants. The scientific literature demonstrates that these reagents can be used to remove the pollutants as sludge or foam, Reagents are divided into modifiers, flocculants, depressants, collectors and frothers, depending on their role the flotation process. Nanomaterial utilization in wastewater treatment has become an intensely studied topic. Collectors reagents, based on hydrophobic nanoparticles, can adsorb a larger quantity of pollutants due to the hydrophilic particle surfaces that facilitate the attachment of pollutants to air bubbles generated by the DAF unit. In the present paper, the researchers present that the role of nanoparticles is to facilitate particle-bubble attachment and/or to minimize detachment. The goal of the study is to consider the influence of nanoparticle parameters on the various stages of particle flotation to demonstrate the key role of nanoparticles in removal of pollutants from textile wastewaters.
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Chettibi, M., A. Abramov, and A. Boutrid. "Physico-chemical models of galena flotation system." World Journal of Engineering 11, no. 5 (November 1, 2014): 447–56. http://dx.doi.org/10.1260/1708-5284.11.5.447.
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Main idea to prevent the ground contamination by heavy metals is to extract them maximally with minimum consumption of chemical reagents. So, a perfect studying of pulp ionic structure, an adjustment of the sulphuric ores flotation parameters and modelling of minerals selectivity variables, by using the thermodynamic method of analysis, the behavior of lead xanthenes surface state in solution and experimental investigation results, allow obtaining quantitative physico-chemical models of minimum necessary xanthenes concentration of lead sulphide complete flotation.The optimal pH values, ensuring a complete flotation of galena agree with the potential of zero or minimum charge of its surface, and the optimal composition of the collector sorption layer consisting both of chemisorbed xanthenes and physically adsorbed dixanthenes.In additional, it was obtained quantitative models for the necessary xanthenes concentration of lead sulphide complete flotation in the case of different oxidation products from the galena surface in pH values from 7,0 up to 12,0.The models derived can be used as the criteria for functional units of automation systems to control and regulate the flotation process in mineral processing plants. All these should conduct to increasing of metals extraction degree with minimum chemical reagents consumption and providing good environmental protection.
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Żak, Sławomir. "Treatment of the Processing Wastewaters Containing Heavy Metals with the Method Based on Flotation." Ecological Chemistry and Engineering S 19, no. 3 (January 1, 2012): 433–38. http://dx.doi.org/10.2478/v10216-011-0033-8.
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Treatment of the Processing Wastewaters Containing Heavy Metals with the Method Based on FlotationThe aim of the studies carried out at full technological scale was to indicate optimal systems of the two-stage precipitation and coagulation (PIX 113 - SAX 18, PAX XL1 - SAX 18, ALCAT 102 - lime milk and SAX 18 - PAX 16) in the process of eliminating heavy metals from wastewaters made in the processing plant producing sub-systems for domestic appliances. Precipitated pollutions were thickened by flocculation and separated by hydrogen peroxide enhanced pressure flotation. The experimental installation of maximal flow capacity: 10.0 m3/d consisted of: the storage-equalization tank, the processing pipe reactor, the pressure flotation station, and the reagent preparation and dosing station. Optimal doses of reagents and a flocculent as well as pressure and saturation time were defined for which maximal reductions in the load of heavy metals were achieved. The usefulness of hydrogen peroxide as a means of enhancing flotation was tested. The use of two-stage precipitation permitted the reduction in heavy metals (Cd, Cu, Cr, Ni, Sn, Zn), eg by applying ALCAT 102 - lime milk at the level exceeding 80%.
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Ksenofontov, B. S., and M. V. Ivanov. "A novel multistage kinetic modeling of flotation for wastewater treatment." Water Science and Technology 68, no. 4 (August 1, 2013): 807–12. http://dx.doi.org/10.2166/wst.2013.303.
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This study develops a new model for description of flotation kinetics. It defines flotation as a process that consists of several stages: separated air bubbles and particles, air bubbles and particles forming an aggregate, aggregate rising to the froth layer. This description significantly differs from known models, which are much simplified. The multistage model gives a novel in-depth description and considers different aspects of flotation, i.e. aggregate formation, which is critically important for flotation to take place. Experimental approval of the new model resulted in its accuracy. The model is to be used for a description of kinetics of all flotation processes in wastewater treatment. It helps in accurate design of flotation treatment plants and may be used for further research of the flotation process.
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Dima, Mihai, Ciocan Doru, and Matei Daniela. "WASTEWATER TREATMENT PLANT- COMMON FILTRATION AND FLOTATION UNIT - DESIGN ASPECTS." Environmental Engineering and Management Journal 5, no. 6 (2006): 1255–61. http://dx.doi.org/10.30638/eemj.2006.104.
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Milosavljevic, Milutin, Dusan Mijin, Sandra Konstantinovic, Natasa Elezovic, Ljiljana Takic, and Ljubinka Drazevic. "A new procedure for the treatment of an industrial waste containing flotation reagents." Chemical Industry 68, no. 3 (2014): 331–39. http://dx.doi.org/10.2298/hemind130618059m.
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Flotation reagents can be transformed to industrial waste if they are stored for a long period of time. Also, if synthesis or drying process is not performed under defined conditions in industrial plants, which produce flotation reagents, batch of waste may arise and be stored as a waste. The chemical composition of this waste depends on the phase in which it was created, but typically includes: unreacted alkali hydroxide, solvent - alcohol and trithiocarbonate and oxidation product - dixanthogenate. In this paper a new laboratory procedure for the treatment of such wastes is described. The identification and separation of industrial waste components is also included. From the separated dixantogenate and xanthate a laboratory synthesis of thioncarbamates is given. In addition, a semi-industrial treatment of waste xanthate is presented. Synthesis of N-alkyl and N,N-dialkyl-O-isobutylthioncarbamates were obtained from the filtrate obtained in the first step. As a by-product, sodium thioglycolate was produced. This by-product is transformed to a thioglycolic acid by the addition of an acid. Also, the synthesis of thioncarbamates from dixanthogenates, isolated from industrial waste as a cake, is desribed. Described waste treatment is additionally interesting due to the production of sulphur as another by-product. Laboratory synthesis gave thioncarbamates in yields from 69.7 to 87.7 %, while the semi-industrial process for the selected batches produced thioncarbamates in yields from 74.2 to 80.5 %. Taking into account the importance of the synthesized compounds as selective flotation reagents, a new procedure of their synthesis from industrial waste is characterized by good yields and purity of the obtained compounds, the simplicity of process, low environmental impact and short reaction times of synthesis.
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Milosavljević, Milutin M., Aleksandar D. Marinković, Milica Rančić, Goran Milentijević, Aleksandra Bogdanović, Ilija N. Cvijetić, and Dejan Gurešić. "New Eco-Friendly Xanthate-Based Flotation Agents." Minerals 10, no. 4 (April 14, 2020): 350. http://dx.doi.org/10.3390/min10040350.
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An optimal laboratory two-step procedure was developed for sodium/potassium O-alkyl carbonodithioate (sodium/potassium alkyl xanthates) production in the form of aqueous solutions. Sodium isopropyl xanthate (Na-iPrX), as the most effective salt in a real ore flotation process, was also produced at an industrial level and introduced as a collector for copper ores. In order to reduce toxicity of the flotation process and improve sustainability by minimising environmental impacts, collector efficiency and selectivity in the flotation process were studied in relation to possible synergism of xanthates combined with the derived biomass and biodegradable green reagents levulinic acid, 5-hydroxymethyl-2-furanacrylic acid (HMFA), and condensation product of hydroxymethylfurfural and levulinic acid. Optimal content of 30% of HMFA in the collector pointed to the possibility of substitution of commercial xanthate collector without significantly affecting its efficiency/selectivity. The density functional theory (DFT) calculations provided insights into the interaction mechanism of Na-iPrX and HMFA with cooper. The benefits of the presented method highlight production simplicity, mild reaction conditions, high purity and yield of products, no by-products, and technological applicability on an industrial scale.
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Vidal, Claudia, Isabel Carrillo-Varela, Pablo Reyes-Contreras, Leopoldo Gutierrez, and Regis Teixeira Mendonça. "Sulfomethylation of radiata pine kraft lignin and its use as a molybdenite depressant in selective chalcopyrite-molybdenite separation by flotation." BioResources 16, no. 3 (June 24, 2021): 5646–66. http://dx.doi.org/10.15376/biores.16.3.5646-5666.
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Sulfomethylation of radiata pine kraft lignin was performed using formaldehyde and sodium sulfite under alkaline conditions to determine its potential as a mineral depressant for the separation of molybdenite and chalcopyrite by froth flotation. Optimal conditions for the sulfomethylation reaction were 20% (w/w) Na2SO3 at 130 °C for 4.2 h, which resulted in lignin with a sulfonate content of 2.2 mmol/g. Microflotation assays showed that the optimized sulfomethylated kraft lignin (OSKL) depressed the molybdenite in flotation by 93% using 200 mg/L OSKL, while only 5% chalcopyrite depression was achieved. The performance of OSKL was compared with those of commercial lignosulfonates, and the OSKL displayed a better ability to separate molybdenite and chalcopyrite, even at lower concentration doses. FTIR and 1H-NMR analyses showed that sulfonic groups were incorporated into the C5 position of the aromatic ring and into the aliphatic chain of the OSKL. The hydroxymethyl content of the OSKL was increased, and most β-O-4′, β-1′ and β-5′ bonds were broken, with the exception of the β-β’ bond. Sulfomethylation gives kraft lignin the chemical characteristics of a wood-based molybdenite depressant, making it an alternative to current reagents used in the chalcopyrite-molybdenite flotation process.
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Maksymiuk, Mariia, Tetiana Kravchuk, Olha Titova, Olena Kosenko, and Olena Spaska. "THE USE OF FLOTATION METHOD FOR PURIFICATION OF WASTEWATERS CONTAMINATED WITH OIL PRODUCTS." WATER AND WATER PURIFICATION TECHNOLOGIES. SCIENTIFIC AND TECHNICAL NEWS 29, no. 1 (July 27, 2021): 11–19. http://dx.doi.org/10.20535/2218-930012021235278.
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Industrial and natural wastewater is one of the factors of environmental pollution, in particular, its water basin. Among others, fuel and oil pollutants are toxic substances that cause significant harm to all living things. It is necessary to create technologies using effective methods of wastewater treatment to solve such problems. It is possible to properly select and effectively use methods of treatment taking into account the nature, condition and concentration of contaminants in wastewater. These are the issues addressed in this article. Particular attention is paid to the use of flotation as a method of purification of stable highly dispersed emulsified wastewater containing oil or fuel contaminants in the technology of this type wastewater treatment. The main objectives of the study were to evaluate the impact of parameters and flotation reagents on the efficiency of the process of purification of stable highly dispersed emulsified wastewater. Flotation of these wastewaters was carried out on a laboratory flotation installation of pneumatic type and compared with the process of wastewater settling over time. Studies have shown that for stable emulsified wastewater containing oil or fuel contaminants with a low content of highly dispersed particles of inorganic nature or a stabilizer is present in them, it is advisable to use the flotation method with flotation units of pneumatic type. Analysing the results, it should be noted that the flotation method significantly reduces the purification time of highly dispersed emulsified wastewater from 3-5 hours of their settling in settling tanks-oil traps up to 10-20 minutes by the method of pneumatic flotation, while the degree of wastewater treatment increases in at least 1.5 - 2 times depending on the presence of fuel or oil contaminants in wastewater. If the wastewater contains a stabilizer, such as a surfactant, it can be used as an effective flotation reagent in the purification of this type of wastewater by flotation, which is not suitable for the settling process.
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Arcos, Felipe, and Lina Uribe. "Evaluation of the Use of Recycled Vegetable Oil as a Collector Reagent in the Flotation of Copper Sulfide Minerals Using Seawater." Recycling 6, no. 1 (January 11, 2021): 5. http://dx.doi.org/10.3390/recycling6010005.
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Considering sustainable mining, the use of seawater in mineral processing to replace conventional water is an attractive alternative, especially in cases where this resource is limited. However, the use of this aqueous medium generates a series of challenges; specifically, in the seawater flotation process, it is necessary to adapt traditional reagents to the aqueous medium or to propose new reagents that achieve better performance and are environmentally friendly. In this research, the technical feasibility of using recycled vegetable oil (RVO) as a collector of copper sulfide minerals in the flotation process using seawater was studied. The study considered the analysis of the metallurgical indexes when different concentrations of collector and foaming reagent were used, considering as collectors the RVO, potassium amyl xanthate (PAX) and mixtures of these, in addition to the methyl isobutyl carbinol (MIBC) as foaming agent. In addition, it was evidenced that the best metallurgical indexes were achieved using 40 g/t of RVO and 15 g/t of MIBC, which corresponded to an enrichment ratio of 6.29, a concentration ratio of 7.01, a copper recovery of 90.06% and a selectivity index with respect to pyrite of 4.03 and with respect to silica of 12.89. Finally, in relation to the study of the RVO and PAX collector mixtures, it was found that a mixture of 60 g/t of RVO and 40 g/t of PAX in the absence of foaming agent presented the best results in terms of copper recovery (98.66%) and the selectivity index with respect to pyrite (2.88) and silica (14.65), improving PAX selectivity and recovery compared to the use of RVO as the only collector. According to these results, it is possible to conclude that the addition of RVO improved the selectivity in the rougher flotation for copper sulfides in seawater. This could be an interesting opportunity for the industry to minimize the costs of the flotation process and generate a lower environmental impact.
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Arcos, Felipe, and Lina Uribe. "Evaluation of the Use of Recycled Vegetable Oil as a Collector Reagent in the Flotation of Copper Sulfide Minerals Using Seawater." Recycling 6, no. 1 (January 11, 2021): 5. http://dx.doi.org/10.3390/recycling6010005.
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Considering sustainable mining, the use of seawater in mineral processing to replace conventional water is an attractive alternative, especially in cases where this resource is limited. However, the use of this aqueous medium generates a series of challenges; specifically, in the seawater flotation process, it is necessary to adapt traditional reagents to the aqueous medium or to propose new reagents that achieve better performance and are environmentally friendly. In this research, the technical feasibility of using recycled vegetable oil (RVO) as a collector of copper sulfide minerals in the flotation process using seawater was studied. The study considered the analysis of the metallurgical indexes when different concentrations of collector and foaming reagent were used, considering as collectors the RVO, potassium amyl xanthate (PAX) and mixtures of these, in addition to the methyl isobutyl carbinol (MIBC) as foaming agent. In addition, it was evidenced that the best metallurgical indexes were achieved using 40 g/t of RVO and 15 g/t of MIBC, which corresponded to an enrichment ratio of 6.29, a concentration ratio of 7.01, a copper recovery of 90.06% and a selectivity index with respect to pyrite of 4.03 and with respect to silica of 12.89. Finally, in relation to the study of the RVO and PAX collector mixtures, it was found that a mixture of 60 g/t of RVO and 40 g/t of PAX in the absence of foaming agent presented the best results in terms of copper recovery (98.66%) and the selectivity index with respect to pyrite (2.88) and silica (14.65), improving PAX selectivity and recovery compared to the use of RVO as the only collector. According to these results, it is possible to conclude that the addition of RVO improved the selectivity in the rougher flotation for copper sulfides in seawater. This could be an interesting opportunity for the industry to minimize the costs of the flotation process and generate a lower environmental impact.
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Yayayürük, Aslı Erdem, and Onur Yayayürük. "Applications of Green Chemistry Approaches in Environmental Analysis." Current Analytical Chemistry 15, no. 7 (October 15, 2019): 745–58. http://dx.doi.org/10.2174/1573411015666190314154632.
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Background: Green chemistry is the application of methodologies and techniques to reduce the use of hazardous substances, minimize waste generation and apply benign and cheap applications. Methods: In this article, the following issues were considered: greener solvents and reagents, miniaturization of analytical instrumentation, reagent-free methodologies, greening with automation, greener sample preparation methods, and greener detection systems. Moreover, the tables along with the investigated topics including environmental analysis were included. The future aspects and the challenges in green analytical chemistry were also discussed. Results: The prevention of waste generation, atomic economy, use of less hazardous materials for chemical synthesis and design, use of safer solvents, auxiliaries and renewable raw materials, reduction of unnecessary derivatization, design degradation products, prevention of accidents and development of real-time analytical methods are important for the development of greener methodologies. Conclusion: Efforts should also be given for the evaluation of novel solid phases, new solvents, and sustainable reagents to reduce the risks associated with the environment. Moreover, greener methodologies enable energy efficient, safe and faster that reduce the use of reagents, solvents and preservatives which are hazardous to both environment and human health.
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Le, Thi, Nóra Schreithofer, and Olli Dahl. "Dissolution Test Protocol for Estimating Water Quality Changes in Minerals Processing Plants Operating With Closed Water Circulation." Minerals 10, no. 8 (July 23, 2020): 653. http://dx.doi.org/10.3390/min10080653.
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To save freshwater resources and comply with environmental regulations, minerals processing operations are transitioning to partially or fully closed water circulation. However, the accumulation of electrolytes and the addition of reagents lead to changes in water composition and may compromise flotation performance and plant maintenance. As a consequence, costly modifications are often required to cope with these challenges. Therefore, knowledge about water quality variation owing to closed water circulation and its potential effect on the flotation performance is crucial. The experimental methodology presented in this paper targeted three main objectives: (1) predicting the tendency of the accumulation of elements and compounds into the process water during comminution, flotation, and storage in tailings facilities; (2) establishing a relationship between laboratory results and plant historical water quality data; and (3) predicting the potential effect of recycling water on flotation performance. The results obtained with Boliden Kevitsa ore showed a good correlation between the water matrix of the actual process water on-site and that obtained in the ore dissolution tests done in the laboratory. The final water composition came close to the process water in terms of major elements and some of the minor elements. Additionally, the work presented in this paper demonstrated that a dissolution loop allowed us to predict the potential impact of the recycling water on the ore flotability. This methodology could serve as an aid for predicting water quality matrix variation and designing closed water circulation systems at existing and new plants.
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Tian, Yudong, Lingyu Piao, and Xiaobo Chen. "Research progress on the photocatalytic activation of methane to methanol." Green Chemistry 23, no. 10 (2021): 3526–41. http://dx.doi.org/10.1039/d1gc00658d.
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This review presents the recent progress of the photocatalytic conversion of CH4 to CH3OH from four aspects: photocatalysts, oxidants, sacrificial reagents, and CH4 activation mechanisms, along with its current status and existing challenges.
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Azevedo, A., R. Etchepare, and J. Rubio. "Raw water clarification by flotation with microbubbles and nanobubbles generated with a multiphase pump." Water Science and Technology 75, no. 10 (February 27, 2017): 2342–49. http://dx.doi.org/10.2166/wst.2017.113.
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Raw water clarification by flotation was studied by injecting air into a centrifugal multiphase pump to generate microbubbles (MBs) and nanobubbles (NBs). Measurements of gas dispersion parameters were performed and optimal conditions were obtained using a pump pressure of 4 bar. Values showed a bubble Sauter diameter of 75 μm, an air holdup of 1.2%, a bubble surface area flux of 34 s−1 and an NB concentration of 1 × 108 NBs mL−1 (measuring 220 nm). Then, a study compared flotation with bubbles formed with the multiphase pump (F-MP) to lamellar settling at the clarification stage of a water treatment plant (WTP), in Brazil. The F-MP showed a higher separation efficiency at high hydraulic loads (9–15 m h−1), even without the use of a polymer, reaching 2 NTU (10–25 NTU raw water feed), which was much lower than the technical goal of the WTP (5 NTU). The results and the technical aspects are discussed, and it is concluded that the employment of MBs and NBs with pumps widens new research lines and applications in modern flotation.
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Zhao, Shu, and Ji Ze Pan. "Overview on the Treatment Technology of Wastewater from Copper Mineral Processing (WCMP)." Advanced Materials Research 750-752 (August 2013): 1369–72. http://dx.doi.org/10.4028/www.scientific.net/amr.750-752.1369.
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During the exploitation and utilization of the mineral resources, varieties of pollutants have been produced, which would impact the natural environment inevitably and bring many adverse effects to ecological environment and the human health. Its worth noting that the wastewater from copper mineral processing (WCMP) is one of the main source of mine environmental pollution. The WCMP is characterized by large quantity and containing large numbers of suspended solids, residual flotation reagents and heavy metals, etc. Wastewater can be discharged and realized reuse only after effective treatment. Recently, natural sedimentation, neutralization, flocculation, oxidation and other treatment techniques by wastes are the commonly used methods to treat the mineral processing wastewater.
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Sbitnev, A. V., M. A. Vodianova, Igor A. Kriatov, L. G. Donerian, I. S. Evseeva, O. V. Ushakova, D. I. Ushakov, I. S. Matveeva, and O. M. Rodionova. "Methodological aspects of the assessment of phytotoxicic properties of ice-melter reagents." Hygiene and sanitation 95, no. 8 (October 28, 2019): 773–78. http://dx.doi.org/10.18821/0016-9900-2016-95-8-773-778.
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One of the main criteria which determine the possibility of the use of a particular type of ice-melter reagents (IMR) is the degree of their safety for the environment and human health, which is reflected in the establishment of safe doses and concentrations. In this regard, the current area of research is to improve the ecological and epidemiological principles of risk assessment of modern types of anti-icing agents. Currently available data concerning monitoring soil studies and the snow held in various cities of Russia, show that there is a process of accumulation of the main components of IMR - sodium and chlorine ions in the areas related to the roadway. The article is designated a problem of existing methodological approaches to the assessment of the phytotoxic impact in the investigation of anti-icing agents in the laboratory. There was executed the comparative characteristics of the results of the preliminary pilot studies on the phytotoxic properties of IMR under using different substrates for germination of seeds - soil and filter paper. The data obtained are characterized by differences in the degree of phytotoxic action of the same species depending upon ice-melter reagents methodical setting circuit laboratory experiment. As a result, there was shown the imperfection of the existing method of rapid analysis in relation to ice-melter materials (IMM).
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Zhang, Liping, Shengnian Wu, Jun Xiang, Xiaofei Jiao, and Jing Wang. "Research on treatment and mechanism of salicylhydroxamic acid flotation wastewater by O3-BAF process." Water Science and Technology 82, no. 5 (August 17, 2020): 861–76. http://dx.doi.org/10.2166/wst.2020.388.
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Abstract Salicylhydroxamic acid is an effective and selective collector for tungsten and molybdenum ores. However, the salicylhydroxamic acid flotation wastewater discharge may cause damage to the water environment for the residual processing reagents with poor biodegradability. Combined O3 and biological aerated filter (BAF) has a well-known potential for removing refractory or toxic organic pollutants. Combined process of O3 and BAF (O3-BAF) was applied to treat the simulated wastewater from W-Mo mineral processing in this study. Compared single ozonation to O3-BAF, various influencing factors were discussed like O3 dosage, reaction time, initial pH value, gas–water ratio and organic loading. Meanwhile, degradation mechanism of salicylhydroxamic acid was reduced. Under the optimal experiment conditions as pH value 8, O3 dosage 1.3 mg·L−1, reaction time 15 min, the five-day biochemical oxygen demand (BOD5)/chemical oxygen demand of potassium dichromate (CODCr) value increased to from 0.19 to 0.35. The effluent was pumped to the following BAF process, when the optimal experiment conditions was organic load = 0.82 kgCODCr (m−3·d−1), gas-water ratio = 6:1, CODCr concentration of effluent was 28.92 mg·L−1 and the removal ratio was 86.26%, while the removal ratio could higher to 91.12% for the O3-BAF combined process. The effluent could meet the discharge and reuse emission standards requirements in China. UV-vis absorption spectra and high performance liquid chromatography showed the degradation pathway of salicylhydroxamic acid by ozone oxidation was salicylhydroxamic acid → salicylic acid + hydroxylamine → catechol → maleic → small molecular organic acid → carbon dioxide + water.
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Pomohaibo, V. M., L. D. Orlova, and N. A. Vlasenko. "Environmental DNA: ecological and genetic aspects." Ecology and Noospherology 27, no. 1-2 (March 29, 2016): 16–24. http://dx.doi.org/10.15421/031602.
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Attention to environmental DNA (eDNA) was motivated by problem of undesirable gene transfer possibility from genetically modified plants to wild bacteria and other organisms. First studies have already examined persistence of DNA from these plants in soil, and also in the samples of nearby groundwater and river for a few kilometers from the place of cultivating. In soil it persists long time enough – from a few days to a few years, and in water – from a few hours to a few days. eDNA excreted from different sources – frozen ice cores, sediments of lakes, soil, caves, water of lakes, rivers and oceans, contains genetic information about biodiversity of present and ancient organisms. Researches revealed an important fact: data of eDNA and other sources, for example pollen, macrofossils, living animals and plants, complement each other, showing more reliable information about the variety of species, than used separately. Therefore the analysis eDNA needs to be not of considered alternative method of ecological researches, but an additional to traditional methods. In the process of study of eDNA it is necessary to take into account five aspects at least: its origin, physical state, conversion, transport and technical challenges. The origin of eDNA remains studied not enough. From a few publications it is known that eDNA comes in different composition excretions, leaves, hair, peeling etc., or as a result of released plasmids and chromosomal DNA from living prokaryotes. There are also possible secondary sources of eDNA – dead bodies and excretions of predators, scavengers, detritivores and coprovores. On the amount of the genetic material, released by organisms in an environment, various ontogenetic, trophic and other factors can have considerably influence. eDNA can be presented in both intracellular and extracellular forms.. Over time intracellular eDNA releases outside by influence of different ecological factors – activity of microorganisms, presence of extracellular enzymes, mechanical destruction etc. In further extracellular eDNA can break in corpuscles of different sizes – mainly within the limits of 1–10 μm. It can be free, adsorbed by other substances or dissolved. At certain conditions the period of eDNA persistence can be very great – from a few hours (in water) to hundred thousands of years (in frozen ice cores). Ancient eDNA is very fragmented and chemically changed by various physical, chemical and biological factors of environment. Substantive eDNA amount is taken up by bacteria and protozoa. Here it quickly metabolizes, but some its fragments can be integrated in a local genome. eDNA is able to be transported to great distance (from a few meters to 10 kilometers) that can appreciably influence on the results of its research. Also the laboratory experiment has certain problems – design (equipment, sequence of operations and condition of it realization), realization of experiment, authenticity of it will depend on quality of equipment and reagents, competence and honesty of scientific personnel etc.), ability of skilled researcher to give interpretation of results. Data that given in our review testifies that the active study of eDNA only began, and further intensive efforts of environmentalists and geneticists are needed in direction of it research. The results of such researches will allow to create the effective methods of scientifically reasonable recreating nature application.
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Florentz, M., M. C. Hascoet, and F. Bourdon. "Biological phosphorus removal at an experimental full-scale plant in France." Canadian Journal of Civil Engineering 14, no. 2 (April 1, 1987): 278–83. http://dx.doi.org/10.1139/l87-040.
Full textAbstract:
In France, all phosphorus removal treatment has been based on precipitation by means of chemical reagents. With a view to reducing costs, a series of laboratory experiments was initiated and subsequently followed up by full-scale studies in early 1984 at the Saint-Mars-la-Jaille treatment plant. This is the first biological P-removal plant to be put on line in France.The plant operates at low loading levels with extended aeration. Nitrification–denitrification is achieved in controlled aerobic and nonaerobic zones through a multi-mini-step process in a plug–flow reactor. Complete nitrate removal results in a release of phosphorus during the anaerobic phase and, hence in a high level of phosphorus accumulation in the aerobic sludge.Phosphorus removal was optimized by replacing the thickener with a new flotation thickener to minimize P-release in the anaerobic sludge blanket. The phosphorus removal levels obtained varied from 35% at the outset of the study to 89% upon stabilization. This paper outlines the basic technical alterations made to ensure efficient phosphorus removal with this type of sewage plant as well as the analytical procedures used, and identifies the polyphosphates accumulated in activated sludge, on the basis of 31-phosphorus nuclear magnetic resonance (31P nmr).Results concerning phosphorus removal at low temperatures are also provided. Key words: activated sludge, wastewater treatment, biological phosphate removal, anaerobic conditions, restricted oxygen, nuclear magnetic resonance, flotation, temperature.
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Bauer, M. J., R. Bayley, M. J. Chipps, A. Eades, R. J. Scriven, and A. J. Rachwal. "Enhanced rapid gravity filtration and dissolved air flotation for pre-treatment of river thames reservoir water." Water Science and Technology 37, no. 2 (January 1, 1998): 35–42. http://dx.doi.org/10.2166/wst.1998.0098.
Full textAbstract:
Thames Water treats approximately 2800Ml/d of water originating mainly from the lowland rivers Thames and Lee for supply to over 7.3million customers, principally in the cities of London and Oxford. This paper reviews aspects of Thames Water's research, design and operating experiences of treating algal rich reservoir stored lowland water. Areas covered include experiences of optimising reservoir management, uprating and upgrading of rapid gravity filtration (RGF), standard co-current dissolved air flotation (DAF) and counter-current dissolved air flotation/filtration (COCO-DAFF®) to counter operational problems caused by seasonal blooms of filter blocking algae such as Melosira spp., Aphanizomenon spp. and Anabaena spp. A major programme of uprating and modernisation (inclusion of Advanced Water Treatment: GAC and ozone) of the major works is in progress which, together with the Thames Tunnel Ring Main, will meet London's water supply needs into the 21st Century.
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Etchebehere, C., M. I. Errazquin, A. Cabezas, M. J. Pianzzola, M. Mallo, P. Lombardi, G. Ottonello, L. Borzacconi, and L. Muxí. "Sludge bed development in denitrifying reactors using different inocula-performance and microbiological aspects." Water Science and Technology 45, no. 10 (May 1, 2002): 365–70. http://dx.doi.org/10.2166/wst.2002.0370.
Full textAbstract:
Aerobic and methanogenic consortia were evaluated as inocula for laboratory scale denitrifying reactors, fed with a synthetic wastewater with acetate as the main electron donor. The denitrifying microflora of inocula and reactors was evaluated by specific denitrifying activity, enumeration and isolation of denitrifiers, which were screened by amplified ribosomal DNA restriction analysis. Reactor performance was monitored by COD and nitrate removal efficiencies and granule size. The aerobic sludge failed to form granules, probably due to the development of a filamentous, nitrate-reducing organism which was characterised by 16SrDNA sequencing as Bacillus cereus. The methanogenic sludge showed denitrifying activity and adapted very rapidly to denitrifying conditions in the two reactors seeded with granules of different sizes. Denitrifiers grew around the granules, increasing the specific denitrifying activity of the sludge over 10-fold. Exopolymer-forming organisms, belonging to the same species, were isolated from both reactors. Granule size increased during operation, but flotation of the aggregates, related to gas retention was observed.
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van Rijt, C. "Cleaning Contaminated Sediments by Separation on the Basis of Particle Size." Water Science and Technology 28, no. 8-9 (October 1, 1993): 283–95. http://dx.doi.org/10.2166/wst.1993.0627.
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In the Netherlands large quantities of contaminated sediment have to be dredged. Because it cannot be relocated directly in the marine environment, the dredged material must be placed in special contained depots which are expensive to construct. In 1989 a programme to reduce the volume of storage space required was started. This paper includes the results of research into the physical aspects of sediment cleaning. Heavy metals are often found in the silt fraction, while organic micro pollutants occur in the silt fraction and sometimes also as tar particles in the sand fraction. The sediment can be cleaned by physical means or by the selective separation of some of the contaminants by froth flotation. Research into the efficiency of using separation on the basis of particle size to clean contaminated sediments from five different sites and also the experience gained during three sediment clean-up operations, indicated that positive effects could only be achieved in sandy sediments. In some cases, owing to the presence of tar particles in the sediment, the quality of the sand fraction was not improved after separation in hydrocyclones. They can be removed from the sand fraction by flotation. Recent developments in selective separation by means of froth flotation, using equipment specially designed for the fine fraction, are promising. The use of duo-flocculants has a favourable influence on the consolidation behaviour of the fine fraction after separation.
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Pedchenko, Larysa, Nazar Pedchenko, Jerzy Kicki, and Mykhailo Pedchenko. "Improvement of the bitumen extraction technology from bituminous sand deposits." E3S Web of Conferences 201 (2020): 01004. http://dx.doi.org/10.1051/e3sconf/202020101004.
Full textAbstract:
Today considerable experience in the development of tar sands is accumulated. However, well-known mining technologies do not cover the entire depth range of natural bitumen deposits. In addition, there are significant energy-intensive technologies and negative environmental impacts. In view of this, the purpose of this work is to improve the method of extracting natural bitumen in site for a deposit interval of 75 – 200 m and to substantiate the basic technological scheme of this method. The proposed method of extracting bitumen from poorly cemented reservoirs in the depth range of 50 – 400 m provides: creation of artificial mine working; the transfer of the rock into the water mixture composition under the action of high pressure jets of a heated mixture of water, a hydrocarbon solvent and a flotation agent; separation from the rock and concentration of bitumen in the production as a result of its heating, dissolution and flotation; selection of depleted bitum slurry from the mine working by gas lift method. The proposed method of extracting bitumen is the transfer of the rock at the site of its occurrence to the suspension condition on the excavation created by the hydraulic production method, separation and concentration of bitumen by dissolving it with a heated hydrocarbon solvent and a flotation agent (hydrocarbon reagents), and extraction in the composition of depleted rock slurry to the surface by the gas lift method. As the preliminary calculations show, the proposed method will allow the efficient extraction of bitumen and highly viscous oil from weakly cemented reservoirs in the depth range of 50 – 400 m. Also, the proposed technology creates the preconditions for the development of oil sands at a depth of 75 – 200 m since there is currently no effective technology for the interval. In addition, it can significantly reduce energy costs, environmental pollution and greenhouse gas emissions.
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Melnychuk, F. S., О. A. Marchenko, A. P. Shatkovskyi, L. M. Melnychuk, М. S. Retman, and О. M. Nichiporuk. "STATUS AND ASPECTS OF STUDYING THE PESTICIDES INFLUENCE ON PRODUCTIVE PROCESSES AND ENVIRONMENTAL SAFETY." Міжвідомчий тематичний науковий збірник "Меліорація і водне господарство", no. 2 (December 12, 2019): 209–16. http://dx.doi.org/10.31073/mivg201902-188.
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Relevance of research. Ukraine's agriculture is one of the world leaders in production and export. The assortment of chemical plant protection products by status on 2019 which used in agriculture has more than two thousand preparations based on hundreds of active substances. In today's difficult climatic conditions, crop growing requires the use of a scientific approach, innovative technology and the introduction of new technologies. One of these is pestigation (irrigation pesticide application), which allows a uniform distribution and precise placement of chemicals independently of weather or field conditions. The selection of a modern assortment of chemicals that can be effectively used in pest control against certain harmful organisms is one of the actual directions of irrigation and requires research in different soil and climatic zones of Ukraine.
The purpose of the study is to investigate the peculiarities of the pesticides application in integrated protection systems and the environmental safety of their use on the example of non-target objects.
Materials and methods of research. Methods of scientific analysis and synthesis, generalization of the results of field and laboratory analyzes were used in the study, which included:
- phyto-expertise of seed and plant material;
- rapid analyzes during the growing season of crops;
- agrochemical analysis of soils;
- detailed soil analysis;
- study of environmental hazards of chemicals for aquatic, soil and terrestrial ecosystems:
- detailed analysis of water.
The application of plant protection products makes it possible to improve the ecological condition of agrocenosis, the conditions of the working area, while increasing crop productivity. Application methods of plant protection reagents with irrigation water and combined protection schemes for row crops, which are used in integrated crop protection systems, are presented. It has been established that one of the significant disadvantage of application plant protection reagents with irrigation water is the limitation of the pesticide treatment time. The developed combined scheme for the row crops protection provides for the prophylactic treatment of pesticide in a short time by the traditional way, depending on the phytosanitary condition of the crops, which provides a significant increase of yield compared to other methods of application. It has also been proven that effectiveness of plant protection reagents is not the same against certain targets upon application different methods of pesticides treatment . Therefore, it is noted that for developing technological schemes for protecting crops against harmful organisms, it is necessary to thoroughly study the phytosanitary situation in the area where crops are located and to determine the targets for which pesticides are applied.
The directions of research on the influence of pesticides on ecosystems are given, namely, the environmental safety of pesticides for the soil ecosystem (toxic effects on groundworms and microorganisms), the aquatic ecosystem (toxic effects on fish, daphnia, and algae) and the terrestrial ecosystem (toxic effects on birds and bees). It is noted that one of the methods to prevent the harmful effects of toxic substances on non-target objects of ecosystems is hygienic regulation of their use. Ecological and toxicological assessment of pesticides was carried out by determining their toxicity after a single injection in a sharp experiment, which allows determining the species susceptibility of a living organism to a chemical reagent. Probit’ analysis method was used to calculate the toxicity in the analysis of the various drugs effects which is the most exact at the present time. The influence of agrochemicals on the structural and functional changes in the microbial cenosis of the soil was determined by a quantitative analysis of agronomical valuable ecological and trophic and taxonomic groups of microorganisms, by assessing the rate of respiration of the soil by the amount of carbon dioxide released.
The tendencies of search and fundamental research in the water management field and land reclamation were analyzed in order to improve modern approaches to plant growing.
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Schofield, T. "Birmingham Frankley water treatment works redevelopment." Water Science and Technology 31, no. 3-4 (February 1, 1995): 213–23. http://dx.doi.org/10.2166/wst.1995.0531.
Full textAbstract:
Severn Trent Water are currently undertaking an extensive capital programme to enhance water treatment facilities at many of its major works. This paper describes the various aspects of the Birmingham Water Treatment Plant Redevelopment Strategy with specific emphasis on the factors that lead to the selection of dissolved air flotation (DAF) as a main stage of clarification and subsequent construction of the largest DAF plant in the world. The design, construction and operation of the plant are reviewed with particular attention to water quality and the use of carbon dioxide within the process stream to produce a stable treated water.
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Fettig, J., V. Pick, U. Austermann-Haun, M. Blumberg, and N. V. Phuoc. "Treatment of tapioca starch wastewater by a novel combination of physical and biological processes." Water Science and Technology 68, no. 6 (September 1, 2013): 1264–70. http://dx.doi.org/10.2166/wst.2013.354.
Full textAbstract:
A pilot plant combining dissolved air flotation, anaerobic degradation in an expanded granular sludge bed (EGSB) reactor and aerobic post-treatment in a vertical flow constructed wetland has been used to treat tapioca starch wastewater for more than 2.25 years. It is demonstrated that organic matter (chemical oxygen demand by >98%), nitrogen (Kjeldahl-N by >90%) and cyanide (total cyanide by >99%) can be removed very efficiently under stable operating conditions. The removal efficiency for phosphorus is lower (total-P by 50%). The treatment concept, which includes several sustainable aspects, e.g. production of energy to be used on-site, low operation demands and minimal use of chemicals, could be interesting for small- and middle-sized tapioca processing plants.
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Adyel, Tanveer Mehedi, Fayezum Nahar Begum, SM Nazrul Islam, and Muhammad Hazifur Rahman. "Assessment of Environmental Aspects and Impacts of Scientific Laboratories of a University: Focus on Gap Analysis and Environmental Management System (EMS) Implementation." Jahangirnagar University Environmental Bulletin 2 (September 5, 2013): 9–17. http://dx.doi.org/10.3329/jueb.v2i0.16325.
Full textAbstract:
Environmental Management System (EMS) has become an important tool for organizations looking towards managing their environmental issues such as pollution, legal compliance and minimizing their environmental impacts. The present study was conducted to assess the environmental aspects and impact of selected scientific laboratories of Jahangirnagar University in Bangladesh with focus on the gap analysis for implementing EMS. Data and information were collected through frequent laboratory visits, focus group discussion, questionnaire survey and key informant interview. It was found that EMS was not implemented in the laboratories and the staffs and researchers of the university had very limited idea about EMS. Surface water, air and soil pollution; unsafe mixing and handling of hazardous materials and chemicals; unsustainable storage of chemicals and reagents; improper use of personal protective equipment found as the main environmental challenges in these laboratories. The maximum negative environmental impact occurred in the chemistry and botany laboratories, as large number of researchers here used high amount of chemicals and cultured media, while the minimum pollution was found in microbiology and environmental sciences laboratories. Although, the overall pollution levels were low, there were lots of gaps in introducing EMS. Therefore, initiatives should be taken. Jahangirnagar University Environmental Bulletin, Vol.2, 9-17, 2013 DOI: http://dx.doi.org/10.3329/jueb.v2i0.16325
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Dionísio, Amália Geiza Gama, Amanda Maria Dantas de Jesus, Renata Stábile Amais, George Luís Donati, Kelber dos Anjos Miranda, Marcelo Braga Bueno Guerra, Joaquim Araújo Nóbrega, and Edenir Rodrigues Pereira-Filho. "Old and New Flavors of Flame (Furnace) Atomic Absorption Spectrometry." International Journal of Spectroscopy 2011 (October 12, 2011): 1–30. http://dx.doi.org/10.1155/2011/262715.
Full textAbstract:
This paper presents some recent applications of Flame Atomic Absorption Spectrometry (FAAS) to different matrices and samples. The time window selected was from 2006 up to March, 2011, and several aspects related to food, biological fluids, environmental, and technological samples analyses were reported and discussed. In addition, the chemometrics application for FAAS methods development was also taken into account, as well as the use of metal tube atomizers in air/acetylene flame. Preconcentration methods coupled to FAAS were discussed, and several approaches related to speciation, flotation, ionic liquids, among others were discussed. This paper can be interesting for researchers and FAAS users in order to see the state of the art of this technique.
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Milligan, Michael S., and Elmar R. Altwicker. "Mechanistic Aspects of the de Novo Synthesis of Polychlorinated Dibenzo-p-dioxins and Furans in Fly Ash from Experiments Using Isotopically Labeled Reagents." Environmental Science & Technology 29, no. 5 (May 1995): 1353–58. http://dx.doi.org/10.1021/es00005a030.
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Jing, Gaogui, Shuai Ren, Yuesheng Gao, Wei Sun, and Zhiyong Gao. "Electrocoagulation: A Promising Method to Treat and Reuse Mineral Processing Wastewater with High COD." Water 12, no. 2 (February 21, 2020): 595. http://dx.doi.org/10.3390/w12020595.
Full textAbstract:
Mineral processing wastewater contains large amounts of reagents which can lead to severe environmental problems, such as high chemical oxygen demand (COD). Inspired by the wastewater treatment in such industries as those of textiles, food, and petrochemistry, in the present work, electrocoagulation (EC) is applied for the first time to explore its feasibility in the treatment of wastewater with an initial COD of 424.29 mg/L from a Pb/Zn sulfide mineral flotation plant and its effect on water reuse. Typical parameters, such as anode materials, current density, initial pH, and additives, were characterized to evaluate the performance of the EC method. The results showed that, under optimal conditions, i.e., iron anode, pH 7.1, electrolysis time 70 min, 19.23 mA/cm2 current density, and 4.1 g/L activated carbon, the initial COD can be reduced to 72.9 mg/L, corresponding to a removal rate of 82.8%. In addition, compared with the untreated wastewater, EC-treated wastewater was found to benefit the recovery of galena and sphalerite, with galena recovery increasing from 25.01% to 36.06% and sphalerite recovery increasing from 59.99% to 65.33%. This study confirmed that EC is a promising method for the treatment and reuse of high-COD-containing wastewater in the mining industry, and it possesses great potential for wide industrial applications.
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Pampuri, Alessia, Andrea Casson, Cristina Alamprese, Carla Daniela Di Mattia, Amalia Piscopo, Graziana Difonzo, Paola Conte, et al. "Environmental Impact of Food Preparations Enriched with Phenolic Extracts from Olive Oil Mill Waste." Foods 10, no. 5 (April 29, 2021): 980. http://dx.doi.org/10.3390/foods10050980.
Full textAbstract:
Reducing food waste as well as converting waste products into second-life products are global challenges to promote the circular economy business model. In this context, the aim of this study is to quantify the environmental impact of lab-scale food preparations enriched with phenolic extracts from olive oil mill waste, i.e., wastewater and olive leaves. Technological (oxidation induction time) and nutritional (total phenols content) parameters were considered to assess the environmental performance based on benefits deriving by adding the extracts in vegan mayonnaise, salad dressing, biscuits, and gluten-free breadsticks. Phenolic extraction, encapsulation, and addiction to the four food preparations were analyzed, and the input and output processes were identified in order to apply the life cycle assessment to quantify the potential environmental impact of the system analyzed. Extraction and encapsulation processes characterized by low production yields, energy-intensive and complex operations, and the partial use of chemical reagents have a non-negligible environmental impact contribution on the food preparation, ranging from 0.71% to 73.51%. Considering technological and nutritional aspects, the extraction/encapsulation process contributions tend to cancel out. Impacts could be reduced approaching to a scale-up process.
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Lively, T. W., C. D. Gowe, and H. R. Woodhead. "Construction of the Iona Outfall submarine section." Canadian Journal of Civil Engineering 17, no. 1 (February 1, 1990): 113–18. http://dx.doi.org/10.1139/l90-014.
Full textAbstract:
In February 1987, the Greater Vancouver Sewerage and Drainage District awarded an $8.5 million contract for the construction of the Iona Outfall submarine section. The contract awarded to the Dillingham–Manson joint venture involved the installation of approximately 3200 m of twin 2.3 m diameter steel outfall, of which 500 m was twin 2.1, 1.8, and 1.4 m diameter steel diffuser sections. The outfall extended from the end of the Iona Jetty into the Strait of Georgia near the mouth of the Fraser River and was 107 m deep at the end of the diffuser. The tender documents suggested a method of installation such that the entire twin outfall pipe was fabricated on an existing jetty complete with flotation pipe and pulled into the water. The contractor submitted an alternative method with the tender and was the successful low bidder. The proposed installation method was to assemble the pipe into nominal 300 m lengths in Dillingham's North Vancouver yard, launch them, tow them to the site, and sink and bolt them together underwater. This paper discusses the more interesting aspects of the project. Key words: construction, pipelines, robotics, sewage treatment, bolted joints.
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Benoufella, F., A. Laplanche, V. Boisdon, and M. M. Bourbigot. "Elimination of microcystis cyanobacteria (blue-green algae) by an ozoflotation process: a pilot plant study." Water Science and Technology 30, no. 8 (October 1, 1994): 245–57. http://dx.doi.org/10.2166/wst.1994.0418.
Full textAbstract:
It is now known that since cyanobacteria (blue-green algae) occur in both swimming and drinking water supplies, and lakes and rivers, they represent an increasing hazard to animal life and human population. Moreover, high algal contents pose also a number of operation problems for water purification plants. The objective of the work is to study the elimination of a Microcystis strain of cyanobacateria by the use of an ozoflotation process which associates the oxidizing properties of ozone and the physical aspects of flotation. The functioning and the efficiency of a pilot unit is presented according to such parameters as: ozone dose, flow rate, coagulants and raw water quality. The use of ozone in pretreatment leads to an inactivation of the algal cells. Experiments let us calculate the specific ozone utilisation rate of Microcystis and the [C.t] (ozone concentration, contact time) curve is determined versus algal removal. Under real conditions, a previous coagulation stage is necessary; best results are obtained with ferric chloride. Preozonation is also of influence on the enhancement of the coagulation efficiency. Association of the ozoflotation process and bilayer filtration can solve the algae problems of waters presenting low turbidity and low organic content, and improve water quality.
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Han, Pei, Qian Lu, Liangliang Fan, and Wenguang Zhou. "A Review on the Use of Microalgae for Sustainable Aquaculture." Applied Sciences 9, no. 11 (June 11, 2019): 2377. http://dx.doi.org/10.3390/app9112377.
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Traditional aquaculture provides food for humans, but produces a large amount of wastewater, threatening global sustainability. The antibiotics abuse and the water replacement or treatment causes safety problems and increases the aquaculture cost. To overcome environmental and economic problems in the aquaculture industry, a lot of efforts have been devoted into the application of microalgae for wastewater remediation, biomass production, and water quality control. In this review, the systematic description of the technologies required for microalgae-assisted aquaculture and the recent progress were discussed. It deeply reviews the problems caused by the discharge of aquaculture wastewater and introduces the principles of microalgae-assisted aquaculture. Some interesting aspects, including nutrients assimilation mechanisms, algae cultivation systems (raceway pond and revolving algal biofilm), wastewater pretreatment, algal-bacterial cooperation, harvesting technologies (fungi-assisted harvesting and flotation), selection of algal species, and exploitation of value-added microalgae as aquaculture feed, were reviewed in this work. In view of the limitations of recent studies, to further reduce the negative effects of aquaculture wastewater on global sustainability, the future directions of microalgae-assisted aquaculture for industrial applications were suggested.
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VanOrden, Steven L., Mark E. Malcomson, and Steven W. Buckner. "Mechanistic and kinetic aspects of chemical ionization mass spectrometry of polynuclear aromatic hydrocarbons and their halogen-substituted analogues using oxidizing reagents: A gas chromatographic-mass spectrometric and Fourier transform mass spectrometric study." Analytica Chimica Acta 246, no. 1 (May 1991): 199–210. http://dx.doi.org/10.1016/s0003-2670(00)80677-7.
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Fronczek, Judith, John D. Gilbert, and Roger W. Byard. "Forensic issues arising in the assessment of chlorine-related deaths in a domestic setting." Medicine, Science and the Law 61, no. 3 (March 31, 2021): 232–35. http://dx.doi.org/10.1177/00258024211002737.
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A retrospective review of autopsy files at the Forensic Science South Australia, Australia, was undertaken over a 20-year period from January 2000 to December 2019 for all cases where chlorine had caused or contributed to death. Two cases were identified out of a total of 25,121 autopsies (0.008%): a 53-year-old man who committed suicide in a cellar with granulated chlorine, and a 49-year-old woman with asthma who died of acute bronchospasm due to exposure to chlorine gas while mixing swimming pool chemicals in her kitchen. Chlorine-related deaths are uncommon in domestic situations. However, the absence of biomarkers and non-specific findings at autopsy complicate the diagnosis, particularly as environmental levels are not stable. While accidents with cleaning agents or swimming pool reagents are the most common event in the literature in domestic settings (exclusive of industrial or transportation accidents), suicide may also very rarely occur. Individuals with asthma and chronic respiratory diseases are at higher risk of an adverse outcome upon exposure to chlorine gas, with inattention to proper storage conditions and handling protocols being additional risk factors.
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Usleber, Ewald, Richard Dietrich, Christine Bürk, Elisabeth Schneider, and Erwin Märtlbauer. "Immunoassay Methods for Paralytic Shellfish Poisoning Toxins." Journal of AOAC INTERNATIONAL 84, no. 5 (September 1, 2001): 1649–56. http://dx.doi.org/10.1093/jaoac/84.5.1649.
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Abstract The current status of immunochemical techniques for analysis of paralytic shellfish poisoning (PSP) toxins is summarized. Important aspects regarding production of the biological reagents necessary for immunochemical methods, the characteristics of polyclonal and monoclonal antibodies against saxitoxin and neosaxitoxin, and the importance of test sensitivity and specificity are discussed. Applications of immunochemical techniques for PSP toxins include microtiter plate enzyme immunoasays and enzyme-linked immunofiltration assays for toxin detection, and immunoaffinity chromatography (IAC) for sample extract cleanup. A major advantage of enzyme immunoassay (EIA) is simplicity and rapidity of the test procedure, and higher sensitivity than other methods. However, quantitative agreement between EIA and mouse bioassay is dependent on antibody specificity and the toxin profile in the shellfish; thus, both over- and underestimation of total toxicity may occur. For screening purposes, however, EIAs offer major advantages over the mouse bioassay, which is criticized in Europe because of animal welfare. A major application of antibodies against PSP toxins is their use for extract cleanup by IAC, which gives highly purified extracts, thereby enhancing determination of PSP toxins by conventional physicochemical methods such as liquid chromatography. IAC can also be used to isolate PSP toxins for preparation of analytical standard solutions.
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Zemlyanova, Marina A., Juliya V. Koldibekova, Ekaterina V. Peskova, Olga V. Pustovalova, and Viktor M. Ukhabov. "Impact of the service terms on biochemical indices in employees at the potassium ore processing enterprise." Hygiene and sanitation 100, no. 5 (June 15, 2021): 451–56. http://dx.doi.org/10.47470/0016-9900-2021-100-5-451-456.
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Introduction. The extraction of potash ores is developing at a significant pace. The flotation method is the way to obtain potassium chloride using chemical reagents that have a toxic effect on the respiratory and nervous system, and liver. The complex long-term impact of occupation factors of the working environment with an increase in work experience leads to a rise in the prevalence of diseases of vital organs and systems. The aim of the study is to assess the change in individual biochemical indices of unfavorable responses on the part of the health of workers at a potassium ore processing enterprise, depending on the length of work experience. Materials and methods. The working conditions of workers were assessed, the content of some aldehydes, hexane, and heptane in biological media was investigated, and changes in many biochemical parameters were established. Results. The factors of the working environment in workers at the potassium ore processing enterprise are characterized by the simultaneous exposure to chemicals (potassium chloride, formaldehyde, propionic and butyric aldehydes, hexane and heptane), physical parameters (industrial noise, the microclimate of the working area, the severity of the labor process) and are assessed as harmful (class 3.1). During long-term labor activity (more than ten years), workers have an accumulation of hexane in the urine (1.4 times) and the increased associated content of norepinephrine in blood plasma (up to 1.3 times), not established in workers with up to ten years of work experience. Workers with ten years of work experience and noise with a level of intensity at workplaces exceeding 14.4 dBA showed an increase of 1.3-2.3 times in the level of homocysteine and lipoprotein, not established in workers with a work experience duration of fewer than ten years. No dependence on the service terms was found for changes in sensitization indices of the upper respiratory tract and hepatocytes’ cytolytic activity. Conclusion. The revealed changes in indices with an increase in the length of service require special attention for the early diagnosis of occupational diseases and the development of measures to prevent emerging changes in critical organs and systems.
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Piaskowski, Krzysztof, and Paweł K. Zarzycki. "Carbon-Based Nanomaterials as Promising Material for Wastewater Treatment Processes." International Journal of Environmental Research and Public Health 17, no. 16 (August 13, 2020): 5862. http://dx.doi.org/10.3390/ijerph17165862.
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In the latest literature search, the technology based on graphite oxide (GO) nanomaterials exhibits a great potential in many aspects of wastewater treatment involving adsorption, photocatalysis, disinfection and membrane process. In this study experimental data involving the carbon element in different forms such as active carbon (AC), graphite and graphene oxide (GO) applied as the active reagents in wastewater treatment are summarized and discussed. The first step was to characterize the aforementioned carbon materials and nanoparticles using various complementary techniques. These include optical microscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Raman spectrophotometry and zeta potential measurements. The second issue was to design the relatively simple experiment enabling us to observe the physicochemical and biological effects of carbon nanoparticles in the presence of sewage water and/or active sludge. Obtained experimental data have been inspected using univariate and multivariate (principal component analysis, PCA) approaches confirming the complex interaction of GO nanoparticles with microorganisms that are present in activated sludge. This experiment enabled the collection of an initial data set to design different large scale investigations focusing on active nanoparticles affecting wastewater purification. PCA calculations clearly revealed that GO strongly affects the wastewater technological processes investigated. It is hoped that the described results will allow the design of smart environmental protection systems in the future.
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Siciliano, Alessio, Carlo Limonti, Giulia Maria Curcio, and Raffaele Molinari. "Advances in Struvite Precipitation Technologies for Nutrients Removal and Recovery from Aqueous Waste and Wastewater." Sustainability 12, no. 18 (September 12, 2020): 7538. http://dx.doi.org/10.3390/su12187538.
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The abatement of nutrient compounds from aqueous waste and wastewater is currently a priority issue. Indeed, the uncontrolled discharge of high levels of nutrients into water bodies causes serious deteriorations of environmental quality. On the other hand, the increasing request of nutrient compounds for agronomic utilizations makes it strictly necessary to identify technologies able to recover the nutrients from wastewater streams so as to avoid the consumption of natural resources. In this regard, the removal and recovery of nitrogen and phosphorus from aqueous waste and wastewater as struvite (MgNH4PO4·6H2O) represents an attractive approach. Indeed, through the struvite precipitation it is possible to effectively remove the ammonium and phosphate content of many types of wastewater and to produce a solid compound, with only a trace of impurities. This precipitate, due to its chemical characteristics, represents a valuable multi-nutrients slow release fertilizer for vegetables and plants growth. For these reasons, the struvite precipitation technology constantly progresses on several aspects of the process. This manuscript provides a comprehensive review on the recent developments in this technology for the removal and recovery of nutrients from aqueous waste and wastewater. The theoretical background, the parameters, and the operating conditions affecting the process evolution are initially presented. After that, the paper focuses on the reagents exploitable to promote the process performance, with particular regard to unconventional low-cost compounds. In addition, the development of reactors configurations, the main technologies implemented on field scale, as well as the recent works on the use of struvite in agronomic practices are presented.
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Albonetti, S., L. Dal Pozzo, and F. Trifirò. "Oxidation Catalysis in Clean Technologies for Fine Chemicals." Eurasian Chemico-Technological Journal 3, no. 4 (July 10, 2017): 221. http://dx.doi.org/10.18321/ectj572.
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The role of heterogeneous catalysis for the production of fine chemicals is reviewed with particular interest for the oxidation in a wide range of aspects of this kind of processes: reaction of oxygen insertion, oxidative dehydrogenation and nitrogen insertion (with ammonia and oxygen). In this review are examined the main processes industrially applied and the best research perspectives in the field of heterogeneous oxidation catalysis for the synthesis of fine chemicals. It is an important point of view in relation with the typical parameters of this field of industrial chemistry and in relation with the driving force of environmental friendly technologies (the line guides of green chemistry) to substitute traditional processes. It is examined either the possibility of the use of gas phases, that is better on an economical and plant point of view, with molecular oxygen, nitrous oxide (it is a very specific oxidant, and it is active in mild conditions) and with the technique of short bed reactor to minimise the effects of the consecutive oxidation reaction particularly on aromatic side chains. Or the use of liquid phases, very useful to work in mild conditions with not stable reagents, with hydrogen peroxide and other alternative oxidants such as regenerable organic hydroperoxides. In the liquid phase reactions it is posed a particular interest in the oxidations carried out with the use of metal doped zeolites, with special attention to tianiasilica catalysts such as TS-1 with the new developments of hydrogen peroxide in situ generation; and heteropoly compounds.
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Karakhanov, Edward. "Preface." Pure and Applied Chemistry 81, no. 11 (January 1, 2009): iv. http://dx.doi.org/10.1351/pac20098111iv.
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The 2nd International IUPAC Conference on Green Chemistry (ICGC-2) was held 14-20 September 2008 aboard the ship "Alexander Radishev" traveling from Moscow to St. Petersburg, Russia. The conference was organized by the Russian Academy of Sciences, the Russian Foundation of Basic Research, the Russian Ministry of Education and Science, and M. V. Lomonosov Moscow State University. The opening ceremony was held in the aula of the new Intellectual Center, Fundamental Library of Moscow State University.The scientific program was centered around a number of fundamental and applied topics such as- environmentally safe reagents and synthesis routes,- heterogeneous catalysis,- homogeneous and enzyme catalysis,- prospective environmentally safe energy sources,- use of renewables in the chemical processes,- environmentally safe technologies of chemical products, and- education in the field of green chemistryThe conference program included 7 plenary lectures, 10 keynote lectures, 37 oral contributions, and 120 poster presentations. Two round-table discussions were also organized. The first was organized by Prof. Hemda Garelick (Middlesex University, London) and examined the environmental context for "green chemistry" and addressed its relationship with the subject area of "environmental chemistry". The second was organized by Prof. Valery Lunin (Chemistry Department of M. V. Lomonosov Moscow State University, Moscow) and was devoted to the discussion of the theoretical and practical aspects of the use of supercritical fluids in chemistry and technology.The conference attracted over 360 participants from 39 countries and 4 continents. IUPAC's green chemistry activities were presented by Prof. P. Tundo, President of IUPAC's Organic and Biomolecular Chemistry Division (INCA and Ca' Foscari University of Venice) and Prof. B. Han, Chair of the IUPAC Subcommittee on Green Chemistry. The plenary and keynote lectures with the choice of oral contributions published in this issue of Pure and Applied Chemistry cover each topic of the conference.We look forward to the 3rd International Conference on Green Chemistry to be held in August 2010 in Canada.Edward KarakhanovConference Editor
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Rakhmanin, Yury A., Kamalya Yu Kuznetsova, Mariya A. Kuznetsova, Roman V. Gorenkov, Oleg Y. Tararikov, and Andrey A. Drozdov. "Best available technologies: selection of domestic disinvasion products in the treatment of industrial waste water and their sediments." Hygiene and sanitation 99, no. 12 (January 25, 2021): 1324–29. http://dx.doi.org/10.47470/0016-9900-2020-99-12-1324-1329.
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Introduction. The authors carried out a comparative analysis of Russian and foreign approaches to regulatory and legal regulation of technologies for industrial treatment of wastewater and its sediments concerning parasitic pathogens. The scientific and applied aspects of introducing domestic lime-containing reagents into disinvasion technology, which can be an alternative to energy-intensive and expensive water treatment methods, have been updated. For consideration by the R.F. Department of water and communal services, the work presents a comparative analysis of Russian and European regulatory and legal acts on the use of reagent compositions of slaked/quicklime in industrial technologies for decontamination and disinfection of sewage and their sediments. Standardization of processes and quality of wastewater disinvasion and its sediments with justification of measures to strengthen hygienic control in the world community of water treatment is updated. Materials and methods. applied methods of overview, comparative analysis to evaluate the regulatory and legal regulation of technological techniques that ensure parasitocidal efficiency of wastewater treatment and its sediments in industrial water treatment. Results. The data of full-scale studies of the waters of the surface reservoirs of the Moscow region and the quality of wastewater treatment at discharge points indicate the low efficiency of disinvestment of urban wastewater from centralized wastewater disposal, entering the hydraulic structures of the metropolis and their contribution to the total level of high parasitic pollution of surface water sources. Conclusion. The analysis of the regulatory regulation of the wastewater treatment and sediments industry showed no development of standardization of wastewater and sediments treatment sub-processes and their complete disinvasion according to parasitic safety criteria. A comparative analysis of measures to enhance hygienic assessment of the quality of cleaning and production of secondary products from formed waste and sediments also showed that preliminary work was done with best available technologies (BAT-5) (information technology support (ITS) 10-2015) on compliance with the sanitary legislation of the Russian Federation, including in terms of legal regulation of standard procedures for the production of by-product (biogas, organic fertilizer, soil, recultivant, etc.) or practically non-hazardous or low-hazard waste intended for placement in the environment.