Wastewater Treatment Methods Research Articles

Investigating a batch-flow photocatalytic LED system for diclofenac removal in wastewater treatment plants: Assessing the influence of reaction conditions on photocatalytic efficiency

This work introduces an innovative batch-flow photocatalytic LED system aimed at efficiently removing diclofenac from wastewater. The study highlights the novelty of fabricating TiO2-loaded carbon fiber photocatalysts through a hydrothermal process, exhibiting a blue shift in their absorption spectrum and enhancing their photon absorption capability. A crucial design feature is the spectral matching between the LED light source and the photocatalyst, which is critical for achieving high photodegradation efficiency. A significant innovation of our study is the testing of the system under real conditions at an operational sewage treatment plant. Here, the designed system demonstrated high efficacy in degrading diclofenac across various treatment stages, highlighting its robustness and adaptability to changing environmental conditions. The highest degradation efficiency was achieved with sewage from the secondary settling tank, where nearly 90 % efficiency was observed after 6 h of irradiation. Moreover, the use of renewable energy sources emphasizes the system's sustainability, presenting a greener alternative to traditional wastewater treatment methods. The investigation not only showcases the system's effectiveness in diclofenac degradation but also its adaptability and stability under real-world conditions, marking a significant advancement in sustainable wastewater treatment technologies.

Life cycle assessment and techno-economic analysis of nanotechnology-based wastewater treatment: Status, challenges and future prospectives

BackgroundWater pollution is a pressing concern stemming from both natural and anthropogenic activities. The challenges associated with water treatment technologies are adsorption (fouling and corrosion of the adsorbent), flocculation (increased sludge generation and high operation cost), ion exchange (high cost and improper ion removal), chemical precipitation (sludge generation), and membrane technologies (membrane fouling and storage). These technologies have been overstretched and struggle to meet increasingly stringent water quality standards. More recent progress has been made in using nanotechnology for wastewater treatment. Nano-technology offers several advantages over traditional technologies. Many nano-based technologies support reuse, require less space, produce fewer toxic intermediates, and are adaptable to support the emerging concept of decentralized water treatment. An essential aspect of this review is a detailed techno-economic analysis, assessing the long-term viability of nanotechnology-based wastewater treatment methods from an economic standpoint. MethodsThis review outlines the current state of nanotechnology in wastewater treatment, addressing environmental and economic aspects, challenges, and future potential. Significant findingsUnderstanding the sustainability and feasibility of these innovative technologies is crucial for their successful integration into wastewater treatment practices, ensuring a more effective and environmentally friendly approach to water remediation.

A comparative study on performance of the conventional and fixed-bed membrane bioreactors for treatment of Naproxen from pharmaceutical wastewater

Here, a comparative study was designed to survey the treatment efficiency of pharmaceutical wastewater containing Naproxen by Membrane bioreactor (MBR) and MBR with fixed-bed packing media (FBMBR). To this end, the performance of MBR and FBMBR in different aeration conditions including average DO (1.9–3.8 mg/L), different organic loading (OLR) (0.86, 1.14 and 1.92 kg COD per cubic meter per day), and Naproxen removal efficiency. The BOD5 removal efficiency, effluent quality and membrane fouling were monitored within 140 days. The results obtained from the present study indicated that COD removal efficiency for FBMBR (96.46%) was higher than that for MBR (95.33%). In addition, a high COD removal efficiency was experienced in both MBR and FBMBR in operational conditions 3 and 4, even where OLR increased from 1.14 to 1.92 kgCOD/m3 d and DO decreased from 4 to < 1 mg/L. Furthermore, the higher Naproxen removal efficiency was observed in FBMBR (94.17%) compared to that for MBR (92.76%). Therefore, FBMBR is a feasible and promising method for efficient treatment of pharmaceuptical wastewater with high concentrations of emerging contaminant, especially, the Naproxen.

Optimization of coagulation wastewater treatment of leather industry

The object of the study was the process of coagulation treatment of wastewater of leather industry enterprises. The treatment of samples of real wastewater from a leather production was investigated. Such wastewater is characterized by high concentrations of pollutants of varying degrees of dispersion, which is due to the use of a large number of various chemicals in the leather production process. During technological operations related to the skinning and processing of skins, these substances enter the wastewater, which is discharged into the sewer. A peculiarity of leather production wastewater is large fluctuations in composition and volume, high concentrations of pollutants, and an increased content of suspended solids. Such waters have certain toxicity. The existing methods of wastewater treatment of leather industry enterprises do not provide the necessary treatment efficiency, do not allow to create a closed circulation of water at enterprises, to use or regenerate valuable components of wastewater, and to ensure their economically feasible disposal. Therefore, the research is aimed at improving the process of coagulation wastewater treatment of leather factories using mathematical modeling and optimization methods. This will make it possible to modernize existing wastewater treatment schemes. The experiments were carried out on the Niva Jar-test laboratory unit, which allows simultaneous examination of 6 samples. Samples of wastewater from leather production after the fattening-filling and dyeing stages were studied. The effectiveness of the coagulation process was determined by the degree of wastewater treatment. The factors were analyzed and the intervals of variation of factors that have a significant impact on the process of coagulation treatment of wastewater from leather factories were established. An experiment plan was drawn up and implemented in order to study the effect of coagulants based on aluminum and ferrum, as well as flocculants on the quality of wastewater treatment. The choice of quality indicators of the coagulation process is substantiated. A statistical analysis of the results of experimental studies was performed, a correlational analysis of the interdependence of parameters and indicators of the quality of the coagulation process was performed. Aluminum-based coagulant has been found to be more effective than iron-based coagulant. The results of mathematical modeling were used to determine the optimal parameters of the coagulation process: pH 10, coagulant dose – 2.5 g/dm3, flocculant dose – 100 mg/dm3.

Limonia acidissima fruit juice mediated eco-friendly synthesis of pervoskite ZnSnO3 nanoparticles: Applications to photocatalytic, electrochemical, antioxidant and antibacterial activities

In anticipation toa growing desire for start-ups to be both green and sustainable, there has been an increase in research focus on the effective removal and degradation of toxic wastewater effluents. A viable and sustainable wastewater treatment method is the use of light to degrade organic contaminants. Photocatalysis holds great potential for addressing environmental, energy, and health challenges, offering sustainable solutions for a wide range of applications with significant societal and economic benefits. In this paper, a multicomponent heterostructure photocatalyst ZnSnO3 was designed and prepared via a simple environmentally responsible path, which included the use of limonia acidissima natural fruit juice as a capping and reducing agent. The ZnSnO3 nanoparticles that were generated were examined using XRD, FT-IR, UV-DRS, SEM-EDAX, TEM, PL and BET investigations. The structure and crystallographic parameters were examined using XRD analysis, and found that the crystallite had orthorhombic geometry. The functional groups were investigated using FTIR spectroscopy. The band gaps (3.59 & 3.69 eV) were estimated using a Tauc plot employing the data of UV-DRS. According to SEM and TEM studies, the morphologies are irregular in shape and have particles that are about 14 nm in size. EDAX analysis was used to determine the elemental composition of the examined ZnSnO3 nanostructures, which demonstrated their purity. Using PL spectroscopy, superficial defects were investigated. The synthesized NPs were used as photocatalysts to degradethe methylene blue dye. Electrochemical measurement of K3[Fe(CN)6] revealed a good sensory activity with a detection limit of 38 μL. K3[Fe(CN)6] is used to detect ferrous ions in biological specimens. Furthermore, it also shows the superior anti-bacterial activity against gram-positive bacteria such as Staphylococcus aureus, and gram-negative bacteria Pseudomonas fluorescens. To the best of our literature survey, it’s the first report for the synthesis of ZnSnO3 nanostructures using the natural reducing agent limonia acidissima natural fruit juice for dye degradation, electrochemical, anti-oxidant, and anti-bacterial applications.

Comparative study of graphene oxide and copper oxide nanoparticle as surface modifiers in microfiltration membranes and adsorbents for efficient removal of textile dyes from contaminated water

Despite technological development, the textile industry still generates effluents with a high content of emerging contaminants, which are harmful to the environment. Conventional wastewater treatment methods struggle to remove emerging contaminants, necessitating advanced techniques. One promising solution is the modification of membranes and adsorption methods. The same modifying agents were used to modify the surface of microfiltration membranes and to create an adsorbent, allowing a comparison of the two processes in water treatment contaminated with dyes. Copper oxide nanoparticles were produced through green synthesis, and polyethersulfone microfiltration membranes were surface-modified using graphene oxide and copper oxide nanoparticles via a pressure-assisted method. Among the tested membranes, MF_GO1.0 + CuO3.0 showed the best performance, demonstrating a synergistic effect between the modifying agents, efficiently removing 97.69 % of Levafix Blue CA dye and recovering 84.88 % of the flux. It also exhibited outstanding removal rates (>99 %) for other textile dyes, such as Solophenyl Blue and Reactive Black 5. Membrane characterization revealed a decrease in contact angle for membranes modified with CuO and GO-CuO, rendering them more hydrophilic and improving permeability. Scanning Electron Microscopy depicted a compacted membrane, characteristic of graphene oxide, with nanoparticles on the surface. Chemical stability tests, conducted at neutral pH for 7 days, demonstrated no significant variation in permeability and contaminant removal. Although adsorption had limited effectiveness in removing the Levafix Blue CA dye, it provided valuable insights into the underlying mechanisms. Comparing membrane modification with adsorption, membranes displayed more efficiency in dye removal and showed enhanced antifouling properties. These results indicate the potential of modified membranes in treating dye-containing wastewater. As dye production increases, these innovative technologies offer promising solutions to reduce the environmental impact of textile industry effluents. By employing such advanced methods, we can work towards safeguarding our water resources and ecosystems from the harmful effects of textile wastewater pollution.

WASTEWATER TREATMENT OF COAL TAR PROCESSING PROCESS FROM PHENOL

The coal tar processing process provides the chemical industry with valuable products: naphthalene, cresol, xylenols, phenol, technical oils and lubricants. The most significant product of coal tar processing is anthracene, which is a raw material for the production of carbon black. The prospects for the implementation of the coal tar processing process entail a danger to the environment and public health.Wastewater formed during the processing process has a complex chemical composition, mainly represented by organic aromatic compounds. Wastewater pollutants significantly exceed discharge standards permissible for discharge into the Centralized Wastewater Disposal System of Settlements and Urban Districts. Phenol, which has the third hazard class according to the standards of maximum permissible concentrations of harmful substances in the waters of water bodies of fishery importance, is particularly dangerous. The toxic effect of phenol leads to the suppression of biocenoses, a decrease in the number of living organisms, negatively affects human health, and can lead to death. Based on the above, in order to reduce the anthropogenic load on the environment and maintain the quality of water resources, it is necessary to carry out a set of environmental measures aimed at wastewater treatment.The article presents methods of wastewater purification from phenol, describes complex purification methods and formulates proposals for the technology of wastewater treatment of the enterprise. Spectral and quantitative chemical analysis were performed to determine the composition of wastewater. Regenerative cleaning methods are proposed. Methods for wastewater treatment have been formulated and implemented. Methods for wastewater treatment of the coal tar processing process are proposed.The aims of research are to reduce the concentration of phenol in wastewater to the standard values permissible for discharge into the Centralized Wastewater Disposal System of Settlements and Urban Districts, based on experimental data; formulate a proposal for the wastewater treatment of the coal tar processing process from phenol.Objectives of the work are to study the composition of the source wastewater; to consider methods of wastewater treatment from phenols; to carry out wastewater treatment, based on the results of the study, to propose a wastewater treatment scheme.The object of the study is the wastewater of the enterprise after the coal tar processing process.

Electrochemical Treatment for Real Hospital Wastewater and its Future Prospect

&lt;p&gt;Purpose: This study investigates the efficacy of electrochemical remediation techniques in treating hospital wastewater, focusing on parameters including turbidity, color, BOD, COD, DO, coliform, and E. coli. Design/Methodology/Approach: The study conducts a comprehensive analysis of various pollutant parameters, evaluating the impact of contact time on pollutant reduction. Electrochemical methods are explored for their potential in mitigating these parameters. Conclusions: The findings demonstrate the effectiveness of electrochemical techniques in reducing a range of pollutant parameters, with significant reductions observed in turbidity (up to 99%), color (51%), BOD (99%), COD (60%), and microbial contaminants such as E. coli and coliform (up to 48%). Notably, the study reveals that higher voltage doesn't consistently result in superior performance. Limitations/Consequences of Research: While the study showcases promising results, certain limitations and challenges are acknowledged, including the need for further research to address these constraints and optimize electrochemical remediation processes. Practical Value: The study highlights the practical potential of electrochemical techniques as an effective means of wastewater treatment in hospital settings, offering insights into their application and benefits for environmental sustainability. Originality and Significance of Results: This research contributes novel insights into the application of electrochemical methods for hospital wastewater treatment, emphasizing their efficacy in reducing various pollutant parameters and providing a foundation for future research directions in this field.&lt;/p&gt;

Electron beam radiation coupled to flocculation for advanced treatment of coking and dyeing wastewater: Performance and synergistic effect

Advanced treatment of industrial wastewater is a tough problem in the field of wastewater treatment. In this study, the electron beam radiation coupled to flocculation process was firstly developed and investigated for the advanced treatment of coking and dyeing wastewater. Three different coupled processes were studied, i.e. electron beam radiation followed by flocculation process (EBF), flocculation followed by electron beam radiation process (FEB), and simultaneous electron beam radiation and flocculation process (SEBF). It was found that different processes had various performances in the removal of targeted organic pollutants. For humic acid, FEB with poly aluminum ferric chloride (PAFC) as flocculants showed the best synergistic effect at 10 kGy, in which the removal of humic acid was 95.2%, while SEBF exhibited the inhibition effect under all the conditions. For Rhodamine B, EBF with PAFC had the highest synergistic effect at 10 kGy, in which the removal of Rhodamine B was 87.4%. For phenol, SEBF with PAFC as flocculants showed the highest synergistic effect at 10 kGy, in which the phenol removal was 64.2%. The transformation of organic pollutants, such as the polymerization was the main reason for the synergistic effect of EBF, while the dissolved iron ions and the enhanced oxidation made major contribution to the synergistic effect of FEB, and the structural change of flocculants and the transformation of organic pollutants during the process of electron beam radiation was mainly responsible for the synergistic effect of SEBF. EBF showed better performance in COD removal for actual coking and dyeing wastewater than FEB, indicating that electron beam radiation could promote the flocculation effect. Considering the operation procedure and treatment cost comprehensively, EBF with PAFC is recommended for the advanced treatment of actual coking and dyeing wastewater. This study could provide a novel and effective method for the advanced treatment of industrial wastewater.

Managing municipal wastewater remediation employing alginate-immobilized marine diatoms and silver nanoparticles

Wastewater remediation has become a major environmental concern in recent years, which has led scientists to look for innovative sustainable solutions. Diatoms have emerged as a potentially effective solution for wastewater treatment, primarily because of their extraordinary ability to absorb nutrients and engage in metabolic processes. The present study aims to accomplish two goals, firstly, green synthesis of silver nanoparticles (AgNPs) utilizing marine diatoms Chaetoceros sp. and Thalassiosira sp. Secondly, encapsulation of diatoms within a Ca-alginate hydrogel bead developed via the gelation method thus introducing a novel way to assess their effectiveness in nutrient bioremediation from wastewater. The study reveals that Thalassiosira sp. mediated AgNPs are very effective in removing phosphate and nitrate, with 74% and 65% removal rates respectively. Conversely, Chaetoceros sp. mediated AgNPs significantly decreased chemical oxygen demand (COD) by 73%. Furthermore, Thalassiosira sp. encapsulated in Ca-alginate hydrogel beads demonstrated significant removal rates: 64% for nitrate, 91% for phosphate, and 78% for COD, respectively. Furthermore, the biochemical profiles of both diatom-entrapped alginate beads were remarkable, and the approach shows potential for effective and sustainable wastewater treatment methods, which can further be investigated for long-term performance, scalability, and environmental impact on sustainability.

Adsorption of Oil from Industrial Wastewater with Eucalyptus globulus Labill. Bark: Optimization Study

Oily wastewater is one of the most hazardous contaminants that can hurt the ecosystem. There is an urgent need to adopt an efficient, eco-friendly, and low-cost material to replace the old traditional treatment methods of oily wastewater that were very expensive in addition to their relatively low efficiency. Eucalyptus bark is considered one of the materials that are rarely used in this field, although it has the characteristics that qualify it to be a distinguished and promising one. The optimum conditions of using Eucalyptus globulus Labill. (Blue gum) bark in the removal of oil from prepared aqueous solutions were concluded before applying in the treatment of real oily industrial wastewater from New Borg El-Arab City, Egypt. The sequential optimization adsorption results were as follows: initial oil concentration, 500 mg/l; adsorbent dosage, 0.5 g/l; pH, 3; exposure time, 45 min; temperature, 20 °C; and shaking rate, 300 rpm. The pretreatment of biomass with H3PO4 proved it to be superior in the oil removal process where the efficacy reached 450.69 mg/g, while the unmodified form came second where the adsorption efficacy reached 395.86 mg/g, after that the NaOH-modified form came third by efficacy reached 315.85 mg/g. The results of SEM elucidated this order of efficacy according to the porosity of the bark surface. FTIR analysis indicated that OH, carboxylic C = O, and carboxylic C-O groups are the contributing groups in the oil adsorption process for the three forms of Eucalyptus bark. The reusability of Eucalyptus bark using n-hexane for one cycle reached 96.34, 97.13, and 95.83% for unmodified, H-modified, and OH-modified forms, respectively, and for five cycles reached 56.29, 58.01, and 55.81% for unmodified, H-modified, and OH-modified forms, respectively. The application of Eucalyptus bark in the H-form in the treatment of real oily wastewater was achieved by efficacy ranging between 91.46 and 96.23% which proves the excellence of Eucalyptus bark in the treatment of oily wastewater.

Temperature effects and molecular insights towards the optimization of polyvinyl alcohol as adsorbent of organic pollutants from aqueous solution

One of the easier methods of wastewater treatment is adsorption due to its simplicity in implementation, environmental friendliness, and economic feasibility. Polyvinyl alcohol (PVA) looks promising as an adsorbent due to its biocompatible, non-toxic, water-soluble and eco-friendly nature. The investigation of PVA for its potential in the adsorption of pollutants has been reported in many studies but the mechanistic understanding of the adsorption is poor. The present study used a theoretical approach through density functional theory and Monte Carlo with molecular dynamics simulations to investigate the adsorption mechanism behaviors of model organic molecules (bromothymol blue (BTB), methylene blue (MB), metronidazole (MNZ) and tetracycline (TC)) on PVA surface. The quantum chemical calculations result showed that with the increase in PVA chains (2, 4, 8, 16, and 32 units), the zero-point energy decreases (from −308.79 to −4922.93 kcal/mol) while the dipole moment increases (from 4.37 to 87.52 Debye). Temperature effect on the PVA chain structures showed the same trends for all the chain units and with the increase in temperature (50–600 K), there are no appreciable changes in zero-point energy, enthalpy energy increases while Gibbs free energy decreases. Considering PVA-pollutant complexes, the effects of temperature on the structures showed that there are no appreciable changes in the zero-point energy, Gibbs free and thermal energies increase with an increase in temperature while the kinetic rate of reactions decreases with an increase in temperature. The enthalpy of the reaction showed different trends with antibiotic and dye complexes. In all the thermodynamic properties investigated and the rate of reaction, the order of affinity of the pollutants with PVA followed TC > MNZ > MB > BTB. Monte Carlo simulation was used to investigate the adsorption behavior of the pollutants on the surface of PVA. The negative adsorption energies (−366.56 to −2266.81 kcal/mol) in terms of affinity towards the pollutants on the surface of PVA followed the sequence TC > MNZ > BTB > MB and the molecular dynamic simulation results followed the same order. The obtained results give valuable insights into the mechanism and performance of PVA as an adsorbent. Most of these computational observations are in good agreement with the available experimental results.

Enhancing anaerobic digestion efficiency in dairy waste water treatment: a comprehensive review of enzyme-based pre-treatment by microorganisms in South Africa

ABSTRACT The escalating global demand for dairy products due to population growth has led to increased production in the dairy industry, resulting in a significant rise in wastewater generation. This wastewater, laden with contaminants such as fats, oils, and greases (FOGs), biological oxygen demand (BOD), chemical oxygen demand (COD), nitrogen, and phosphorus, poses a threat to freshwater sources. Anaerobic digestion (AD) is considered the optimal treatment method for dairy wastewater, but the high-fat content poses challenges like reactor clogging. To overcome this, various authors propose and implement an enzymatic pre-treatment strategy that improves FOG and organic content removal, increases biogas production, and addresses economic and environmental concerns. Despite the proven efficacy of enzymatic pre-treatment, a significant drawback is the associated cost. However, it remains a promising strategy for enhancing the biodegradability of complex organic compounds in dairy effluents. This review delves into the crucial role of enzyme-producing microorganisms in enhancing AD efficiency for dairy wastewater treatment, emphasizing their potential benefits and addressing the economic and environmental considerations associated with this approach.

Strategies for biological treatment of waste water: A critical review

Global water demand is continuously growing due to rising population and associated industrial and agricultural activities. However, these factors are also polluting the existing water bodies and therefore, limiting the water supply. Increasing level of contaminants poses risk to human, wildlife and the environment. Widening gap between water demand and supply creates water stress. Therefore, treatment of waste water becomes imperative in order to ensure sustainable development of planet earth. Conventional methods utilizing physical, chemical and biological processes are generally adopted for this purpose. These methods are further modified so as to enhance the efficiency and economy of the treatment process as well as to make them more eco-friendly. None of the conventional or advance technology is individually sufficient for appropriate treatment of wastewater. Therefore, more efficient hybrid methods are required. The development of such hybrid methods needs detailed information about various treatment methods. This paper critically reviews the conventional and advanced biological methods used for waste water treatment. The main objective of this review is to present vital information about various biological treatment methods forming the basis for the development of sustainable hybrid methods for waste water treatment.

2D/2D heterojunction of MgAlTi-LDH/g-C3N4 with oxygen vacancy engineering for enhanced photocatalytic activities under natural sunlight

Semiconductor photocatalysis is an ideal method for wastewater treatment. However, the rapid recombination of photogenerated electron-hole pairs limits the improvement of photocatalytic efficiency. Constructing heterostructures by different energy band-matched semiconductors and surface defect engineering are considered as effective strategies to inhibit the recombination of photogenerated electron-hole pairs. Herein, a novel MgAlTi-LDH/g-C3N4 heterojunction was fabricated by in-situ growth of oxygen vacancy rich MgAlTi-LDH on ultrathin g-C3N4 nanosheets first time for the degradation of methylene blue (MB) under natural sunlight. The optical absorption properties, crystalline phase, microstructure, and morphological analysis of the fabricated materials are subsequently characterized by XRD, FT-IR, UV–vis DRS, TEM, BET and XPS. Owing to Ti-doping, oxygen vacancy rich MgAlTi-LDH exhibited superior photocatalytic activity for MB degradation, which was 5.5 times of that of MgAl-LDH. Furthermore, MgAlTi-LDH/g-C3N4 heterostructures showed a higher photocatalytic activity under visible light irradiation, which was 5.9, 4.9, and 3.2 times of that of MgAl-LDH, MgAlTi-LDH and g-C3N4, respectively. Upon natural sunlight irradiation, MgAlTi-LDH/g-C3N4 can degrade 95 % of MB after 130 min of irradiation. The improvement of photocatalytic activity of MgAlTi-LDH/g-C3N4 was attributed to the synergistic effect of MgAlTi-LDH and g-C3N4, surface oxygen vacancies, and heterostructure interface. This work promotes a new strategy to synthesize high-efficiency photocatalysts for the removal of organic pollutants from wastewater by constructing heterojunctions with surface defects.

Review on natural method for wastewater treatment

Review on natural method for wastewater treatment

Sorption of divalent metal ions from aqueous solutions on activated carbon with its further separation through electroflotation

Currently, there are multiple methods for wastewater treatment from metal ions. One of the leading methods is the sorption process. The advantage of sorption purification is its ability to extract substances from multi-component mixtures and its high efficiency with low concentrations of wastewater contamination. The purpose of this work was to study the sorption capacity of the “OU-B” activated carbon in relation to metal ions (Cu2+, Zn2+, Mn2+). The following tasks were set: establishing optimal parameters for sorption in a static mode, approximating the obtained data by linear forms of kinetic and adsorption equations, as well as obtaining the ability to separate coal particles from aqueous solutions by electroflotation. To study the patterns, we used the following research methods: low-temperature nitrogen adsorption, atomic absorption spectrometry, and nephelometry. The optimal parameters for sorption in a static mode (sample size of coal, process time, initial concentration of metal ions) were established experimentally. The maximum degree of extraction of metal ions in the course of sorption was achieved with a 1:133 ratio of coal to aqueous solution during 60 minutes and was 82% for Cu2+, 73% for Zn2+, and 63% for Mn2+. The obtained sorption results were analysed using the kinetic models of Zeldovich-Chen-Clayton of pseudo-first and pseudo-second order and adsorption models of Langmuir, Freundlich, Temkin, Dubinin-Radushkevich, and Flory-Higgins. The analysis showed that the sorption of Cu2+, Zn2+, and Mn2+ on OU-B carbon occurred according to the mechanism of physical adsorption, which was described by the sorption models of Langmuir and Freundlich and the Zeldovich-Chen-Clayton kinetic model. The separation of used sorbents and the aqueous phase was a difficult task from a technological point of view due to the small size of carbon particles. The article showed the prospects of using electroflotation for extracting OU-B carbon from aqueous solutions: the degree of extraction of coal particles reached 97-99% when cationic or non-ionic SAS were added to the solution.

TECNOLOGÍAS DEL BENEFICIADO DE CAFÉ Y TRATAMIENTO DE EFLUENTES LÍQUIDOS

&lt;p&gt;&lt;strong&gt;Background.&lt;/strong&gt; The coffee processing process generates polluting solid and liquid waste. It is possible to reduce its effects through treatments that allow its use. &lt;strong&gt;Objective.&lt;/strong&gt; To analyze the alternatives for the management of the effluents and residues generated in the coffee processing process to reduce its effects and to show treatments that have had positive results. &lt;strong&gt;Methodology.&lt;/strong&gt; To obtain the information, specialized search engines were used in databases such as: RESEARCHGATE, GOOGLE SCHOLAR, CIRAD, CATIE, IICA, ELSEVIER, SCIENCIE DIRECT, REDALYC, SCOPUS. An exploration and analysis of 100 documents related to the following topics was carried out: 1) history of the use of effluent treatment systems in coffee processing, 2) types of treatments for the management of liquid and solid waste, 3) operation of these technologies, capacity, place where the research was carried out, variables measured, as well as the capacity of these systems. The search period was planned from 1980 to 2023. The history of the beginning of the systems for the treatment of waste generated in coffee processing was also investigated. The key words used for the search were: wet processing, wastewater, solid and liquid waste, coffee by-products, treatment systems, chemical oxygen demand, biological oxygen demand, total solids, turbidity, anaerobic treatments, and aerobic treatments. Approximately 100 documents were reviewed for the writing of the paper. &lt;strong&gt;Main findings.&lt;/strong&gt; Research has been reported since 1980. Colombia and Mexico have focused on the development of machinery to mechanize processing operations to reduce water use, as well as anaerobic treatment systems, biodigesters and wetlands. &lt;strong&gt;Implications.&lt;/strong&gt; It is necessary to know the main methods of wastewater treatment in the coffee processing process to determine the most suitable in coffee growing regions. &lt;strong&gt;Conclusions.&lt;/strong&gt; Anaerobic biodigestion technology is the most used for the treatment of liquid effluents and with the best results. For the solid effluent, different alternatives are used for substrate such as the extraction of substances for industry, composting and biomaterials, among others.&lt;/p&gt;

Geospatial investigation on self-purification capacity of river Estuaries in the Caspian region: reducing heavy metals pollution

AbstractIn today’s context, the adoption of sustainable wastewater treatment methods is crucial. River estuaries have the potential to offer an economically viable and environmentally friendly solution for wastewater treatment through the flocculation of pollutants. This study investigates the role of river estuaries flowing into the southern part of the Caspian Sea in the treatment of heavy metals. Two sets of experiments were designed for this purpose. The first set involved adjusting a series of discrete aquaria in various salinity regimes, while the second set utilized only one aquarium. The results from the first set indicate the capacity of the studied estuaries to remove heavy metals through the flocculation process in the following order: Zn (70%) &gt; Mn (60%) &gt; Cu (49%) &gt; Pb (24%) &gt; Ni (19%). However, the removal rates in the second set were reduced as follows: Zn (57%) &gt; Mn (56%) &gt; Cu (40%) &gt; Pb (20%) &gt; Ni (17%). It was observed that the flocculation process exhibits an unstable nature. Furthermore, the findings reveal that heavy metals flocculation primarily occurs upstream of the estuary. However, instability in the flocculation process occurs downstream, where water parameters undergo drastic changes. Statistical analyses indicate that an increase in pH plays a significant role in the destabilization of flocs. Conversely, the initial concentration of heavy metals, dissolved oxygen, and redox potential have a positive impact on the flocculation process.

Understanding key factors determining the effect of particle scouring efficiency on membrane fouling mitigation in AnFMBRs: Correlation analysis via machine learning

Particle scouring methods offer several advantages, including low energy consumption, ease of operation, and effective fouling control. The anaerobic fluidized bed membrane bioreactor is considered to be the most efficient wastewater treatment method with zero energy consumption, as it produces bioenergy and has lower energy requirements compared to conventional processes. However, membrane fouling in AnFMBRs can be affected by various factors such as fluidized particle hydrodynamics, particle properties, and operating conditions. To identify the primary factors affecting membrane fouling control in AnFMBRs, machine learning methods were utilized. Analysis of datasets from previous studies revealed several key findings. The location of the membrane in the reactor, particle momentum, and particle size were identified as the major parameters that govern membrane fouling reduction. Additionally, the optimal condition for AnFMBRs was determined to involve a membrane height-to-reactor height ratio of ≤0.5 and the use of particles with diameters of 1.5–3.0 mm. Furthermore, the use of smaller fluidized particles was shown to decrease particle scouring efficacy, making it less cost-effective. Machine learning models were successfully established to predict fouling, thus providing a comprehensive understanding of the dominant factors influencing membrane fouling control in AnFMBRs and offering an efficient method for optimizing fouling mitigation.