Problem Of Wastewater Treatment Research Articles

Study of the kinetics of the extraction of zinc ions from wastewater by ferritization

Given the relevance of the problem of wastewater treatment from heavy metal ions, and in particular from zinc ions, it is necessary to study the regularities of the process. One of the key aspects is the kinetics of the process and the dependence of the ion extraction efficiency on the duration of the purification process. Reducing the time of the process makes it possible to reduce the cost of electrical energy for technological processes, in particular for the activation of the reaction mixture by heating or electromagnetic pulses.
 Based on the obtained results of the experiment, a mathematical model of the kinetics of the process of extracting zinc ions from wastewater by ferritization with thermal and electromagnetic pulse activation was built. A regression model was used for data processing and an algorithm for calculating the dependence of the degree of purification on the time of the process was proposed. Determined the degree of purification of wastewater from heavy metal ions at different values ​​of the process duration. The expediency of carrying out the process of ferritization cleaning with a duration of 10-15 minutes has been substantiated.

Ce‐Doped MoO3 Photocatalyst as an Environmental Purifier for Removal of Noxious Rhodamine B Organic Pollutant in Wastewater

Wastewater treatment and management have been hot topics for the past three decades. Water reuse can help to alleviate the problems of water shortage and wastewater treatment in practice. Water can be used for household uses once the organic contaminants are removed. In this research, bare MoO3 and Ce‐doped MoO3 are fabricated using a straightforward hydrothermal method for wastewater treatment. The different analytical techniques are utilized to study the physiochemical features of all the synthesized products. Rhodamine B (RhB) is reduced photocatalytically under exposure of visible light to ascertain the possible capacity. The photocatalytic results suggest that the photoreduction of RhB with 2% Ce‐doped MoO3 exhibits a greater photocatalytic activity of 91.83% than the pure and other doped materials. The kinetic study of 2% Ce‐doped MoO3 displays the greater rate constant of 0.0163 min−1 and a lower Rct value of 0.95 Ω. The research indicates that the doping approach is a very effective way to decrease the bandgap and boost RhB's photocatalytic reduction. Other environmental and water‐related problems can be solved using Ce‐doped MoO3's improved physical and structural characteristics.

Scalability of the multi-anode plug flow microbial fuel cell as a sustainable prospect for large-scale design

Designing scalable and cost-effective microbial fuel cells for practical applications is a problem in wastewater treatment. The performance and scalability of the new multi-anode plug flow MFC (MAPF-MFC) with a shared cathode, in three different scales or anodic configurations (C1, C3, and C6) and at three different flow rates, Q (Q1: 15.33 mL/min, Q2: 46 mL/min, and Q3: 76.66 mL/min) were evaluated. The results revealed a consecutive increase in power density, energy recovery, organic removal rate, and a decrease in internal resistance scaling up. The MAPF-MFC configuration C6 (57.59 mW/cm2) produced 6.9-times and 27.9-times that of C3 and C1 in power density, and 1.6-times and 3.5-times in CE with 38.2%, that of C3 and C1, respectively. C6 (45.8 gCOD/L/day) was also 24.8-times and 48-times that of C3 and C1, and 1.5-times to 1.8-times higher in continuous current generation. C1, however, achieved 82% COD removal efficiency, 1.05-times and 1.3-times that of C3 and C6, respectively. A cost-benefit analysis of the configurations revealed a potential annual power output of $28,048.9/a by C6 and a 0.062 cost-benefit ratio. The study demonstrated the MAPF-MFC's capacity to significantly improve power production, energy recovery, and wastewater treatment while scaling up MFCs at a high economic potential.

Construction of novel type II heterojunction WO3/Bi2WO6 and Z-scheme heterojunction CdS/Bi2WO6 photocatalysts with significantly enhanced photocatalytic activity for the degradation of rhodamine B and reduction of Cr(VI)

As a novel photocatalyst with visible light responsiveness, Bi2WO6 has excellent activity in treating wastewater containing organic pollutants and noble metals. However, its photocatalytic action is limited due to the rapid recombination of photogenerated electrons and holes. Based on the study of Bi2WO6, a type Ⅱ heterojunction photocatalyst (WO3/Bi2WO6) and a Z-scheme heterojunction photocatalyst (CdS/Bi2WO6) were constructed. Composites exhibited higher catalytic activity than pure Bi2WO6. The degradation efficiency of RhB(50 mg/L) and reduction efficiency of Cr(VI) (50 mg/L) by 5%WO3/Bi2WO6 catalyst within 60 min of photocatalytic reaction was 98.82% and 53.82%, respectively. The degradation efficiency of RhB and reduction efficiency of Cr(VI) by 15%CdS/Bi2WO6 catalyst was 99.52% and 69.52%, respectively. By studying the structural composition, microscopic morphology, photoelectrochemical performance, and light absorption performance of the catalysts of the two different systems. These mechanisms may help to explain the reasons for the enhanced activity of the composite photocatalysts. In addition, mixed wastewater containing organic pollutants (RhB) and heavy metal ions (Cr(VI)) was used to simulate real and complex wastewater, which provided more ideas for wastewater treatment problems.

Technologies Based on Phototrophic Microorganisms As a Promising Way to Achieve Carbon Neutrality in Urban Agglomerations

Today, a significant part of the world’s population lives in urban agglomerations. A high building density, a large number of vehicles, and industrial enterprises negatively affect both the air quality in the city itself and the climate in general, releasing a significant amount of carbon dioxide. In this regard, there is a need not only to revise the structure of urban developments and strategies for their greening, but also to propose new technologies that radically change the ecological situation. In this paper, solutions using phototrophic microorganisms are considered as such a technology. It is shown that photobioreactors for their cultivation can be successfully integrated into urban systems, while in addition to air purification, the problem of surface wastewater treatment for their further use can also be solved. A wide range of products obtained from the biomass of phototrophic microorganisms significantly increases the economic attractiveness of this approach. Modern technologies in the field of the Internet of Things make it possible to successfully integrate photobioreactors into the urban digital environment.

Functional cellulose aerogel nanocomposites with enhanced adsorption capability and excellent photocatalytic performance

A novel functional cellulose carbon aerogel@Na2Ti3O7@Cu2O (CA@Na2Ti3O7@Cu2O) nanocomposite was prepared by in situ growth technique and impregnation method, and its photocatalytic and adsorption properties were explored. The cationic intercalation structure of Na2Ti3O7 nanosheets gives CA@Na2Ti3O7@Cu2O nanocomposites excellent adsorption capacity of heavy metal ions (31.0–118.7 mg/g). The Cu2O nanoparticles in CA@Na2Ti3O7@Cu2O nanocomposite showed excellent photocatalytic activity, and the removal rate of methylene blue (MB) was up to 99 %. Furthermore, the CA@Na2Ti3O7@Cu2O nanocomposites could be easily regenerated and reused, providing a new way to effectively solve the problem of wastewater treatment containing heavy metal ions and organic dyes.

Activation of bentonite and palygorskite adsorbents by acid under microwave radiation

The problem of wastewater treatment, since the second half of the 20th century, is relevant for all countries of the world. There are quite a few purification methods, however, adsorption methods are simple and effective methods of water purification. The advantages of these methods are high efficiency, the possibility of treating wastewater containing several substances, as well as the recovery of these substances. Active carbons, synthetic sorbents and some production wastes (ash, slag, flask, sawdust), mineral sorbents - clays, silica gels, alumogels and metal hydroxides are used as sorbents. The research illustrates the possibility of acid activation of bentonite and palygorskite clays using microwave radiation. It has been established that the microwave activation of bentonite leads to the destruction of the structure, the expansion of the surface and the change in the pore structure, which affects the textural characteristics. The concentration values of hydroxyl groups indicate the presence of surface active sites that can participate in adsorption. The results were presented as tables and as a graph.

Waste water treatment from oil products by precipitation

At a number of enterprises, there is a problem of wastewater treatment from oil products. It was studied the oil products composition in the wastewater in industrial sewage system of a machine-building plant. Gravimetric method was used to determine the concentration of oil products in wastewater. When detecting oil products in concentrations exceeding the MPC, it was researched the wastewater treatment from petroleum products by precipitation. It was also calculated the granulometric composition of oil products in wastewater and the main design parameters of the settling tank.

Prediction Model of Wastewater Pollutant Indicators Based on Combined Normalized Codec

Effective prediction of wastewater treatment is beneficial for precise control of wastewater treatment processes. The nonlinearity of pollutant indicators such as chemical oxygen demand (COD) and total phosphorus (TP) makes the model difficult to fit and has low prediction accuracy. The classical deep learning methods have been shown to perform nonlinear modeling. However, there are enormous numerical differences between multi-dimensional data in the prediction problem of wastewater treatment, such as COD above 3000 mg/L and TP around 30 mg/L. It will make current normalization methods challenging to handle effectively, leading to the training failing to converge and the gradient disappearing or exploding. This paper proposes a multi-factor prediction model based on deep learning. The model consists of a combined normalization layer and a codec. The combined normalization layer combines the advantages of three normalization calculation methods: z-score, Interval, and Max, which can realize the adaptive processing of multi-factor data, fully retain the characteristics of the data, and finally cooperate with the codec to learn the data characteristics and output the prediction results. Experiments show that the proposed model can overcome data differences and complex nonlinearity in predicting industrial wastewater pollutant indicators and achieve better prediction accuracy than classical models.

Renewable and eco-friendly ZnO immobilized onto dead sea sponge floating materials with dual practical aspects for enhanced photocatalysis and disinfection applications

In this study, we have investigated the role of natural dead sea sponge (DSS, Porifera) as a three-dimensional (3D) porous host substrate for the immobilization of nanostructured ZnO material towards the development of ZnO based floating photocatalysts for efficient removal of methylene blue (MB) dye under the illumination of sunlight. After photodegradation, the treated water after dye degradation contains several pathogens, different disinfectants or chemical reagents that are essentially used. This is not the case for DSS as it can naturally kill any pathogens during the wastewater treatment process. To explore these functions, ZnO nanosheets were incorporated onto DSS via hydrothermal protocol and the as prepared ZnO/DSS hybrid material exhibited approximately ∼100% degradation efficiency for the removal of MB. Importantly, the degradation kinetics associated with the fabricated ZnO/DSS was remarkably accelerated as evidenced by the high values of degradation reaction rate constants (3.35 × 10–2 min−1). The outperformance of ZnO/DSS could be attributed to the adsorption caused by its 3D porous structure together with the high rapid oxidation of MB. Furthermore, the high charge separation of electron–hole pairs, natural porosity, and abundant catalytic sites offered by the hybrid ZnO/DSS floating photocatalyst have enabled quantitative (∼100%) degradation efficiency for MB. Finally, the excellent reusability results confirm the feasibility of using natural ZnO/DSS-based photocatalyst for practical solution of wastewater treatment and other environmental problems.

The Solution Combustion Synthesis of ZnO Powder for the Photodegradation of Phenol

Nanoscale and submicron powder of zinc oxide (ZnO) is known as a highly efficient photocatalyst that is promising for solving the problem of wastewater treatment from toxic organic pollutants including phenol and its derivatives. The results of laboratory studies of ZnO preparation by a simple, energy-saving, and highly productive method of solution–combustion synthesis from a mixture of solutions of zinc nitrate and glycine, as well as the use of the ZnO powder synthesized by combustion for the photocatalytic decomposition of phenol, are presented. The modes and characteristics of combustion, phase composition, chemical composition, and structure of the combustion product at different ratios of glycine with zinc nitrate were determined. It is shown that calcination at 650 °C reduces the content of carbon impurity in the combustion product to ~1 wt.% and leads to obtaining ZnO powder in the form of porous agglomerates up to 100 μm in size sintered from crystalline nanoscale and submicron ZnO particles with an average crystallite size of 44 nm. The ZnO powder exhibits high photocatalytic activity, leading to the almost complete degradation of phenol in an aqueous solution under the action of ultraviolet irradiation in less than 4 h.

Psyllium-Husk-Assisted Synthesis of ZnO Microstructures with Improved Photocatalytic Properties for the Degradation of Methylene Blue (MB).

Wastewater from the textile industry is chronic and hazardous for the human body due to the presence of a variety of organic dyes; therefore, its complete treatment requires efficient, simple, and low cost technology. For this purpose, we grew ZnO microstructures in the presence of psyllium husk, and the role of psyllium husk was to modify the surface of the ZnO microstructures, create defects in the semiconducting crystal structures, and to alter the morphology of the nanostructured material. The growth process involved a hydrothermal method followed by calcination in air. Additionally, the psyllium husk, after thermal combustion, added a certain value of carbon into the ZnO nanomaterial, consequently enhancing the photocatalytic activity towards the degradation of methylene blue. We also investigated the effect of varying doses of photocatalyst on the photocatalytic properties towards the photodegradation of methylene blue in aqueous solution under the illumination of ultraviolet light. The structure and morphology of the prepared ZnO microstructures were explored by scanning electron microscopy (SEM) and powder X-ray diffraction (XRD) techniques. The degradation of methylene blue was monitored under the irradiation of ultraviolet light and in the dark. Also, the degradation of methylene blue was measured with and without photocatalyst. The photodegradation of methylene blue is highly increased using the ZnO sample prepared with psyllium husk. The photodegradation efficiency is found to be approximately 99.35% for this sample. The outperforming functionality of psyllium-husk-assisted ZnO sample is attributed to large surface area of carbon material from the psyllium husk and the synergetic effect between the incorporated carbon and ZnO itself. Based on the performance of the hybrid material, it is safe to say that psyllium husk has high potential for use where surface roughness, morphology alteration, and defects in the crystal structure are vital for the enhancing the functionality of a nanostructured material. The observed performance of ZnO in the presence of psyllium husk provides evidence for the fabrication of a low cost and efficient photocatalyst for the wastewater treatment problems.

Current progress in treatment technologies for plastic waste (bisphenol A) in aquatic environment: Occurrence, toxicity and remediation mechanisms

Bisphenol-A (BPA) is a type of endocrine disrupting compound (EDC) that is being widely used in the production of polycarbonate and epoxy resins. In the last few years, human exposure to BPA has been extensively high due to the continuous increment in the Annual Growth Rate (AGR) of the BPA global market. The presence and transportation of BPA in the environment could cause serious damage to aquatic life and human health. This paper reviewed the literature on the exposure and toxicity mechanisms of BPA and advanced analytical techniques for the detection of BPA in the environment and human beings. The study indicated that BPA can cause damaging effects on numerous tissues and organs, including the reproductive system, metabolic dysfunction, respiratory system, immune system and central nervous system. On the basis of reported studies on animals, it appears that the exposure of BPA can be carcinogenic and responsible for causing a variety of cancers like ovarian cancer, uterine cancer, prostate cancer, testicular cancer, and liver cancer. This review paper focused mainly on the current progress in BPA removal technologies within last ten years (2012–2022). This paper presents a comprehensive overview of individual removal technologies, including adsorption, photocatalysis/photodegradation, ozonation/advance oxidation, photo-fenton, membranes/nanofilters, and biodegradation, along with removal mechanisms. The extensive literature study shows that each technology has its own removal mechanism and their respective limitations in BPA treatment. In adsorption and membrane separation process, most of BPA has been treated by electrostatic interaction, hydrogen boning and π-π interations mechanism. Whereas in the degradation mechanism, O* and OH* species have played a major role in BPA removal. Some factors could alter the removal potential and efficiency of BPA removal. This review paper will provide a useful guide in providing directions for future investigation to address the problem of BPA-containing wastewater treatment.

Synthesis and study of new nonionic polyether water clarifier for oily wastewater

AbstractIn order to solve the problem of oily wastewater treatment in Shengli Oilfield, tert‐butyl phenol (TP) series nonionic polyether water clarifiers were synthesized by polymerization with p‐tert‐butyl phenol (PTBP) as the initiator. The water clarifiers were characterized by Fourier‐transform infrared spectroscopy (FT‐IR) and the interfacial tension test was carried out. The TP series of water clarifiers effect were evaluated by the oil content and suspension content in the clean water experiments. In addition, the effects of dosage and temperature on the water effect were discussed through the control variable method. The experimental results showed that the oil removal rate of TP6 can reach 95% and the suspension removal rate can reach 92% when the dosage of water clarifier was 40 mg/L, the cleaning water temperature was 55°C, and the cleaning water time was 30 min. The oily wastewater colour after cleaning was clear and transparent with the TP series of water clarifiers, and the effect was better than with commercial water clarifiers.

Pemanfaatan Biji Kelor (Moringa oleifera) Sebagai Koagulan Dalam Menurunkan Kadar Fosfat (PO4) Pada Air Limbah Rumah Sakit

One alternative to solving the problem of wastewater treatment is to treat wastewater using Moringa seeds as a natural coagulant. Moringa seeds contain the bioactive compound rhamnosyloxy-benzil isothiocyanate, which can adsorb and neutralize mud and metal particles contained in suspension waste with dirt particles floating in water, so it has very potential to be used as a natural coagulant to clean water.This research was conducted to determine the method of wastewater treatment by using Moringa Oleifera Seeds for Phosphate (PO4) Content in Hospital Wastewater and calculating the difference in weight variations of Moringa oleifera seeds (1000, 1500, and 2000 mg / L) with deposition time (15 minutes). This type of research is quantitative research with true experimental research. The research design used was a randomized control-group pretest-posttest design.The results showed that in the range of observations made, the weight of Moringa seed powder as an effective coagulant was 2000 mg / L hospital wastewater with a deposition time of 15 minutes capable of removing phosphate levels by 28.77%.

Metallurgical Dust as an Adsorbent of Heavy Metal Ions from Washing Wastewater of Electroplating Industries

The problems of wastewater treatment of electroplating industries from heavy metal ions are considered . The prospects and relevance of the sorption method of purification are shown. The results of a study on the use of dust from metallurgical industries for the extraction of hexavalent chromium, zinc, copper, nickel, and cadmium ions from the washing water of galvanic productions are presented. The possibility of intensifying the deposition of suspension particles in a settling tank, the polymer bottom of which is equipped with electromagnets, is shown. The parameters of processing the extracted sediments into anticorrosive pigments have been determined. An experimental batch of MA-25 paint was prepared on the basis of pigment from sorption purification waste. The properties of the resulting coating were investigated and it was found that it complies with all the standards imposed on this brand of paint except for color.

Fabrication of anti-fouling and photocleaning PVDF microfiltration membranes embedded with N-TiO2 photocatalysts

Polyvinylidene fluoride (PVDF) membranes are promising materials for purifying and recycling wastewater in cold regions due to their high mechanical strength and low temperature stability. However, in practical wastewater treatment services, PVDF is easily fouled by organic pollutants because of its hydrophobic characteristics. In addition, because of the large amount of reagent utilized in the conventional cleaning process, a new hydrophilic membrane with simple cleaning characteristics needs to be developed. In this work, a novel anti-fouling membrane (N-TiO2@PVDF) was obtained by implanting a N-TiO2 photocatalyst into a PVDF membrane. N-TiO2@PVDFshows a more homogeneous pore size distribution and a larger average pore diameter, which results in a higher water flux (1017.8 L/m2•h compared to 217.4 L/m2•h PVDF), higher model pollutant bovine serum albumin (BSA) solution flux and higher BSA rejection rate (92.3% compared to 81.4% for PVDF). Furthermore, N-TiO2@PVDF shows an outstanding hydrophilicity performance compared to the PVDF membrane. The water contact angle of N-TiO2@PVDF 14 decreases sharply from 93.7° (PVDF) to 53.5°, and the BSA adsorption amount decreases significantly from 1.41 mg/cm2 (PVDF) to 0.05 mg/cm2. The total fouling ratio of N-TiO2@PVDF is decreased to a value of 25.5% compared to a value of 70.3% for PVDF, and the irreversible BSA fouling ratio is even decreased to 5.8% compared to 57.2% for PVDF. This result indicates that N-TiO2@PVDF shows outstanding antifouling performance. The N-TiO2@PVDF membrane also has a photocleaning function, and the BSA flux recovery ratio reaches up to 94.7% under simulated sunlight irradiation for 2 h without additional treatment. The results obtained from hydroxyl radical (OH) detection indicate that OH degradation of organic pollutants is the dominant mechanism for the N-TiO2@PVDF photocleaning. This anti-fouling and photocleaning N-TiO2@PVDF membrane offers a solution to wastewater treatment problems of membrane brittleness and easy fouling in cold places. It can also be a good choice for the drinking water purification process.

TREATMENT OF INDUSTRIAL WASTEWATER FROM CADMIUM COMPOUNDS

The article is devoted to the problem of solving an urgent environmental problem - the rational use of water resources. The most harmful and widespread toxic substances in wastewater, andin some cases in natural waters, are heavy metal compounds, in particular cadmium, which belongs to the 2nd class of hazard. The presence of a large number of metal processing enterprises, chemical, machine-building, and metallurgical enterprises with electroplating shops for applying metal coatings leads to the formation of a large amount of metal-containing wastewater, which makes the problem of wastewater treatment containing heavymetals quite relevant.Among the developed approaches, sorption methods are important, as they ensure the mostcomplete removal of toxic ions, especially from solutions with low concentrations that exceedpermissible standards. The successful development of sorption water treatment technology is based on the development of high-quality sorbents. The development of effective methods for the treatment of industrial wastewater from heavy metal ions is an urgent problem of our time. The paper presents the results of experimental studies of water purification from cadmium ions using ferromagnetic sorbents obtained from waste industrial solutions. The optimal parameters of the purification process from the dose of magnetite, pH of the medium, at different ratios of Fe2+ : Fe3+ ratio in magnetite.

BIOTRANSFORMATION OF WASTEWATER PRODUCTION OF BAKERY YEAST WITH BIOGAS GENERATION

Baking yeast enterprises are a source of environmental pollution by concentrated wastewater. They are usually diluted with water and discharged into sewerage. It is rational to use methane fermentation, which will ensure the removal of pollutants and make the process cost-effective through the use of biogas and digestion. Therefore, it is relevant to study the question of the influence of fermentation parameters on the cleaning efficiency. The aim of the work is to study the methane fermentation of yeast production effluents in a continuous mode. Objectives: analysis of solving the problem of wastewater treatment of yeast plants, study of the influence of process parameters (dilution rate, addition of cobalt salts) on the efficiency of treatment; gas generation; vitamin production. Initial COD of effluents 4500 mg O2/dm3, pH 6. Cultivation regime – continuous, dilution rate 4,1·10–3, 6,2·10–3, 8,2·10–3, 12,4·10–3 hours–1. Cleaning efficiency 78,9 %. High values ​​of dilution rate cause overload of activated sludge, which leads to reduced cleaning efficiency. The presence of cobalt also has a depressant effect. A significant amount of biogas (up to 5,2 dm3/dm3) is produced with a high content of methane (up to 85 %), which is an alternative fuel. As the dilution rate increases, the biogas and methane content decrease. With increasing dilution rate from 4,1·10–3 to 12,4·10–3 hours–1, biogas decreased from 1,11 to 0,94 dm3/g CODloading, and from 1,43 to 1,39 dm3/g CODfermentation. Similarly to the effect on the depth of purification, the inhibitory effect of cobalt on methanogeneration is observed. Digestion is a valuable fertilizer with a significant content of cobalamin vitamins (up to 95 μсg/g). The addition of cobalt salts stimulates the synthesis of vitamins, providing an increase of 26,7 to 51,6 %, improving the ratio between active and inactive forms.

Analysis of Common Problems in Industrial Wastewater Treatment and Countermeasures

Analysis of Common Problems in Industrial Wastewater Treatment and Countermeasures