Efficient Wastewater Treatment Research Articles

Enhancing wastewater treatment efficiency through hydrodynamic cavitation and advanced oxidation processes: Experimental insights and comparative analysis

BackgroundThe escalating industrial wastewater production mandates effective treatment methods to mitigate environmental and health risks. Hydrodynamic cavitation (HC) and its combination with advanced oxidation processes (AOPs) offer promising approaches for wastewater pollution reduction. MethodsThis study investigates the enhancement of HC efficiency for Chemical Oxygen Demand (COD) reduction by integrating hydrogen peroxide (H2O2) and air injection. Synthetic wastewater resembling industrial effluent COD levels serves as the experimental medium. Varied inlet pressures, H2O2 concentrations, and air injection rates were examined to gauge their impact on COD reduction. Significant FindingsHigher inlet pressures directly correlate with increased COD reduction, highlighting intensified cavitation effects. Combining HC with H2O2 or air, especially when directly injected into the venturi throat, showcased substantial synergy, significantly reducing COD levels. Notably, the maximum extent of COD reduction, achieved at 51.85 %, was with the combination of (HC+H2O2+Air). The COD reduction percentages for other processes, including HC alone, (HC+Air tank injection), (HC+Air throat injection), (HC+H2O2 tank injection), and (HC+H2O2 throat injection), were 4.21 %, 19.7 %, 20.9 %, 37.8 %, and 39.4 %, respectively.

Fault Detection of Urban Wastewater Treatment Process Based on Combination of Deep Information and Transformer Network.

As one of the hot issues of concerns during modern social development, the wastewater treatment process is acknowledged to be a process with complex biochemical reactions and susceptible to an external environment, featuring strong nonlinear and time correlation characteristics, which are difficult for traditional mechanism-based models to tackle. For many classical data-driven fault detection methods, a complete retraining process is necessary to monitor every new fault, and most of the current neural network-based strategies rarely achieve satisfactory monitoring accuracy or robustness either. Giving full consideration to the aforementioned problems, this article takes advantage of position encoding, residual connection, and multihead attention mechanism embedded in the Transformer structure to establish an effective and efficient wastewater treatment process fault detection model, where offline modeling and online monitoring are performed successively to achieve accurate detection of the faults. In the experimental part, the advantages of the proposed method are strongly verified through the simulation monitoring of 27 faults on the benchmark simulation model 1 (BSM1), where the false alarm rate (FAR) and miss alarm rate (MAR) of the established method are proved to be significantly lower than those of the compared state-of-the-art methods.

Design and fabrication of magnetically recoverable SnO2/CoFe2O4 nanocomposite for enhanced visible light-driven wastewater treatment

This study emphasizes the critical importance of ensuring the availability of clean and secure water resources amid global concerns about water contamination, highlighting the necessity for effective and enduring methods to eliminate hazardous pollutants. The research introduces a sustainable approach to environmental protection through the creation of a high-performance photocatalyst, employing a co-precipitation route to incorporate CoFe2O4 onto SnO2 for efficient wastewater treatment under solar light irradiation. Comprehensive composition and morphological studies of the SnO2/CoFe2O4 composites are conducted using techniques such as XRD, SEM, TEM, Raman, UV–Vis, PL spectra, and FT-IR spectra. The synergistic behavior of the SnO2/CoFe2O4 composite results in efficient separation of electron/hole pairs, reducing the recombination rate and leading to improved photocatalytic performance under solar-light illumination. Notably, the rate constant for Chromium (VI) removal reaches 87 % and the degradation of Rhodamine 6G attains 92 % within 105 mins intervals. The catalyst demonstrates stability and ease of regeneration through a five-cycle recycle study, further supporting its potential for practical application in wastewater treatment.

Evaluation of Chaetoceros Sp. microalgae bio filters efficiency in urban wastewater treatment

Evaluation of Chaetoceros Sp. microalgae bio filters efficiency in urban wastewater treatment

Benchmarking of industrial wastewater treatment processes using a complex probabilistic hesitant fuzzy soft Schweizer–Sklar prioritized-based framework

The objective of this research work is to effectively handle the intricate and uncertain nature of decision-making in the context of industrial wastewater treatment. The prioritization of wastewater treatment is of utmost importance in order to save the environment, promote human health, ensure adherence to legal regulations, conserve resources, and foster overall sustainability. The demand for efficient and sustainable wastewater treatment processes is increasing globally, but selecting appropriate treatment technologies for industrial effluents is challenging due to its complex nature. Our study aims to provide a systematic framework for evaluating and selecting treatments based on efficacy, affordability, and environmental impact. Aggregation operators are one of the fundamental ideas in the framework of information fusion for addressing real-life problems. Numerous scholars have made significant contributions to the development of aggregation operators specifically designed for multi-parameter decision-making (MPDM) whenever circumstances are characterized by uncertainty. Regrettably, the current operators can only be employed within strict limits and constraints. Therefore, this research formulates novel prioritized aggregation operators that alleviate the restrictive constraints associated with the current operators. After this, we present a new methodology that combines the Schweizer–Sklar prioritized aggregation operators with a complex probabilistic hesitant fuzzy soft framework. For this purpose, we develop the averaging aggregation operators and geometric aggregation operators. Following that, we proceed to examine the theorems and properties associated with them by providing rigorous proofs. Then, we develop a novel decision-making technique with a numerical example based on the wastewater treatment process. Through this novel technique, the best process is the activated sludge process. We perform the validity tests to evaluate the feasibility and effectiveness of MPDM techniques.

AUTOMATED EFFLUENT TREATMENT SYSTEM

This paper introduces the Programmable Logic Controller (PLC) Based Automated Effluent Treatment System as an innovative solution for efficiently managing industrial effluents. The system employs sophisticated technology, including PLCs and various sensors, to automate and optimize the treatment process. Specifically designed for industries like electroplating, where water contamination is prevalent, the system effectively monitors and controls water levels, temperature, gas presence, and pH levels to ensure the safe disposal of effluent. Through a detailed exploration of its components and functionalities, this paper demonstrates how the PLC-based system enhances efficiency, reliability, and environmental sustainability in industrial wastewater treatment. Key Words: Programmable Logic Controller, Automation, Effluent treatment plant, Environment safety, Sewage, Chemicals.

Polyaniline-Based Cationic Porous Organic Polymers for Fast and Efficient Anion-Exchange-Driven Capture of Cr2O7 2.

Efficient treatment of wastewater contaminated with carcinogenic Cr(VI) has been a long-term challenge for both academic and industrial research efforts. Removal of Cr(VI) species by ion exchange is a relatively simple and efficient method, and its combination with highly tailorable nanomaterials is promising for the treatment of such wastewater. Here, we report a type of cationic porous organic polymer (POP), namely, PTPA-PIP, which can be prepared simply by converting the corresponding aromatic polyamine PTPA to its protonated form, thereby significantly increasing its hydrophilicity and ability to disperse homogeneously in water, crucial for application in water treatment. In addition to detailed characterization of the physicochemical properties of PTPA-PIP (including using Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET), and solid-state NMR techniques), adsorption experiments demonstrate that PTPA-PIP removes low-concentration dichromate anions with very high performance, including excellent exchange capacity (maximum capacity of 230 mg Cr2O7 2-/g PTPA-PIP), ultrafast removal (initial adsorption rate of 83 mg g-1 min-1), excellent selectivity (∼10% loss of adsorption capacity in the presence of 40-fold concentration of competing anions), as well as superior reusability (reusable for at least 5 cycles without compromised performance). These results demonstrate that PTPA-PIP is an outstanding candidate for application in industrial settings for the effective removal of harmful Cr(VI) pollutants in wastewater.

Construction of direct-Z-scheme heterojunction photocatalyst of g-C3N4/Ti3C2/TiO2 composite and its degradation behavior for dyes of Rhodamine B

Direct-Z-scheme g-C3N4/Ti3C2/TiO2 photocatalyst with giant internal electric field were prepared by one-step aqueous sonication self-assembly method using g-C3N4 and MXene of Ti3C2 as the source materials. The chemical composition and structure of the catalysts was characterized by FT-IR, XRD, SEM, TEM and XPS. The XPS characterization indicated that Ti3C2 was partially oxidized to TiO2 during the composite process. As a result, an efficient direct-Z-scheme heterojunction structure consisting of the g-C3N4 and TiO2 with Ti3C2 as an electron bridge was constructed. The photocatalytic performance of the prepared catalysts was evaluated by degrading the rhodamine B (RhB) wastewater. Compared with the single g-C3N4, the g-C3N4/Ti3C2/TiO2 composite photocatalyst exhibited efficient and stable photocatalytic degradation ability, with a degradation efficiency as high as 99.2% for RhB under optimal conditions (2% Ti3C2, pH=3). The high degradation performance of g-C3N4/Ti3C2/TiO2 for RhB was attributed to the combination of Ti3C2, TiO2, and g-C3N4 components, forming a direct-Z-scheme heterojunction with a high-speed electron transport channel structure. The role of Z-scheme heterojunctions in electron transport is verified by photoelectrochemical characterization, along with photoluminescence (PL). Our research provides a simple method to design photocatalysts by constructing direct-Z-scheme electron transport channels for highly efficient treatment of dye wastewater.

Low-coordinated Fe–N3 sites in carbon nitride for efficient photo-Fenton wastewater treatment

Single-atom coordinated host catalyst offers a promising strategy for photo-Fenton induced wastewater treatment due to the tunable photophysical/chemical properties. However, designing efficient atomically dispersed single-atom catalysts with highly reactive unsaturated coordination remains a challenge. Herein, we designed the low-coordinated Fe–N3 site in carbon nitride (FeCN), which showed excellent degradation efficiency for 4-CP declined to 90.1 % in Tap water and 88.2 % in Dalian Lake within 1h. X-ray absorption near-edge spectroscopy (XANES) demonstrated the monoatomic Fe was anchored to CN via the low-coordinated Fe–N3 structure. Density Functional Theory (DFT) and photoelectric characterizations demonstrated that the Fe–N3 site could facilitate the photo-generated charge migration to the Fe–N3 site due to the asymmetric electron distribution of Fe–N3 site and the Fe_d orbitals occupying the conduction band positions. Besides, project density of states (PDOS) illustrated the strong electronic interaction between the Fe–N3 site and OH*, which confirmed the Fe–N3 site facilitated the activation of H2O2 and further accelerated the performance of photo-Fenton wastewater treatment. This study can provide insights into the design of highly active low-coordination single-atom catalysts and the Fenton-like mechanisms.

Sorting Out the Latest Advances in Separators and Pilot-Scale Microbial Electrochemical Systems for Wastewater Treatment: Concomitant Development, Practical Application, and Future Perspective.

To date, dozens of pilot-scale microbial fuel cell (MFC) devices have been successfully developed worldwide for treating various types of wastewater. The availability and configurations of separators are determining factors for the economic feasibility, efficiency, sustainability, and operability of these devices. Thus, the concomitant advances between the separators and pilot-scale MFC configurations deserve further clarification. The analysis of separator configurations has shown that their evolution proceeds as follows: from ion-selective to ion-non-selective, from nonpermeable to permeable, and from abiotic to biotic. Meanwhile, their cost is decreasing and their availability is increasing. Notably, the novel MFCs configured with biotic separators are superior to those configured with abiotic separators in terms of wastewater treatment efficiency and capital cost. Herein, a highly comprehensive review of pilot-scale MFCs (>100 L) has been conducted, and we conclude that the intensive stack of the liquid cathode configuration is more advantageous when wastewater treatment is the highest priority. The use of permeable biotic separators ensures hydrodynamic continuity within the MFCs and simplifies reactor configuration and operation. In addition, a systemic comparison is conducted between pilot-scale MFC devices and conventional decentralized wastewater treatment processes. MFCs showed comparable cost, higher efficiency, long-term stability, and significant superiority in carbon emission reduction. The development of separators has greatly contributed to the availability and usability of MFCs, which will play an important role in various wastewater treatment scenarios in the future.

Synergistic promotion of microalgal growth and copper removal from synthetic wastewater by nanoscale zero-valent iron particles.

The increasing concentrations of heavy metals in livestock wastewater pose a serious threat to the environmental safety and human health, limiting its resource utilisation. In the present study, microalgae and nanoscale zero-valent iron were selected to construct a coupled system for copper-containing wastewater treatment. The addition of 50 mg·L-1 nanoscale zero-valent iron (50 nm) was the optimal value for the experiment, which could significantly increase the biomass of microalgae. In addition, nanoscale zero-valent iron stimulated microalgal secretion of extracellular polymeric substances, increasing the contents of binding sites, organic ligands, and functional groups on the microalgal surfaces and ultimately promoting the settling of microalgae and binding of heavy metals. The coupled system could quickly adapt to copper-containing wastewater of 10 mg·L-1, and the copper removal rate reached 94.99%. Adsorption and uptake by organisms, together with the contribution of zero-valent iron nanoparticles, are the major copper removal pathways. Overall, this work offers a novel technical solution for enhanced treatment of copper-containing livestock wastewater, which will help improve the efficiency and quality of wastewater treatment.

Multi‐stimuli‐responsive hypercrosslinked microporous polymeric adsorbent

AbstractIt is challenging but of practical meaning to provide adsorbents with multiple responsive properties. Here, we report an intelligent microporous polymeric adsorbent constructed by block copolymer‐grafted microporous polymer nanospheres. With its multi‐stimuli‐responsive functions, the adsorbent shows rapid fluorescent response to temperature, pH, and organic reagents. Moreover, it also demonstrates super‐fast adsorption of pollutants in water, enabling efficient treatment of wastewater.

Green algae Ulva lactuca-derived biochar-sulfur improves the adsorption of methylene blue from water

The present investigation explores the efficacy of green algae Ulva lactuca biochar-sulfur (GABS) modified with H2SO4 and NaHCO3 in adsorbing methylene blue (MB) dye from aqueous solutions. The impact of solution pH, contact duration, GABS dosage, and initial MB dye concentration on the adsorption process are all methodically investigated in this work. To obtain a thorough understanding of the adsorption dynamics, the study makes use of several kinetic models, including pseudo-first order and pseudo-second order models, in addition to isotherm models like Langmuir, Freundlich, Tempkin, and Dubinin–Radushkevich. The findings of the study reveal that the adsorption capacity at equilibrium (qe) reaches 303.78 mg/g for a GABS dose of 0.5 g/L and an initial MB dye concentration of 200 mg/L. Notably, the Langmuir isotherm model consistently fits the experimental data across different GABS doses, suggesting homogeneous adsorption onto a monolayer surface. The potential of GABS as an efficient adsorbent for the extraction of MB dye from aqueous solutions is highlighted by this discovery. The study’s use of kinetic and isotherm models provides a robust framework for understanding the intricacies of MB adsorption onto GABS. By elucidating the impact of various variables on the adsorption process, the research contributes valuable insights that can inform the design of efficient wastewater treatment solutions. The comprehensive analysis presented in this study serves as a solid foundation for further research and development in the field of adsorption-based water treatment technologies.

Synthesis and characterization of La-doped SnO2 nanoparticles with different shape: A comprehensive study on morphology, structure, and photocatalytic efficiency for eco-friendly wastewater treatment

New controllable synthetic approach to obtain of La-doped SnO2 nanoparticles based on the combination of co-precipitation method with post synthetical hydrothermal treatment has been developed. Nanoparticles with various shape (3 nm spheres and 5 nm cubes) and structural parameters, i.e. different amount of oxygen vacancies and defects, and different dopant concentrations of 11 mol% and 33 mol% were fully characterized using XRD, FTIR, XPS and Raman spectroscopy, TEM, SSA evaluation, optical absorption spectra study, luminescence spectroscopy, including quantum chemical calculations.It was shown that hydrothermal treatment (240 °C during 6 h) promotes nanoparticle growth via the mechanism of oriented attachment. Original computational approach based on the calculation of interaction energies between ions and crystal facets was engaged to study the growth process.The presence of intrinsic photoluminescence (406, 414, 438, 460, 500 and 676 nm) for all obtained samples was established, determined by a complex set of different parameters for sub-10 nm nanoparticles.Photocatalytic efficiency of 95 % on the example of methylene blue under commercially available LED lamp described via quantum chemical modelling and tested on the example of a colorless antibiotic solution. A clear dependance of the morphological and structural parameters on the photocatalytic properties has been obtained and studied in detail.Novel concept based on a combination of chemical and computational method, for effective visible-light driven photocatalyst synthesis with potential antibacterial properties for complex eco-friendly wastewater treatment was proposed.

Bacterial and microalgal co-fixation for remediation of industrial wastewater contaminated with arsenic, mercury, and other pollutants

Microbial remediation is an efficient approach for improving heavy metal-contaminated water environments. Herein, this article developed a composite bacterial agent (CBA) with a high heavy metal tolerance. Within 12 h, the CBA demonstrated removal efficiencies of 65.18 ± 1.53% for As and 60.73 ± 0.94% for Hg in wastewater. This study prepared bacterial–algal fixed spheres (BAFS) to further enhance the removal efficiencies of As and Hg. Moreover, during desorption using 0.1 mol/L HNO3 for 60 min, the BAFS maintained high removal efficiencies for As and Hg after five adsorption–desorption cycles. Applying BAFS to industrial wastewater collected from factory outfall caused substantial reductions in chemical pollutants and other heavy metals. Scanning electron microscopy analysis further revealed that the internal cavities formed through the crosslinking of immobilized materials provided excellent survival carriers for bacteria and microalgae. Infrared spectroscopy analysis demonstrated the involvement of three functional groups, namely -OH, -CH2-, and C-O-C, in pollutant adsorption. Additionally, microbial community diversity analysis indicated that immobilization effectively preserved the pollutant adsorption ability of the microorganisms, increasing the abundance of functional microbial populations. These characteristics improved the efficiency of industrial wastewater treatment while promoting recycling.

Hydrothermal synthesis of high crystallinity ZSM-5 zeolite from coal gasification coarse slag and mother liquor circulation for efficient coal chemical wastewater purification.

A hydrothermal synthesis method was developed to produce high crystallinity ZSM-5 zeolite using coal gasification coarse slag (CGCS) as the raw material. Instead of the expensive NaOH(s.), Na2SiO3(s.) was utilized to activate, depolymerize, and recombine Si and Al elements in the CGCS. The mother liquor circulation technology was employed to recover and reuse raw materials and residual reagents (Na2SiO3(aq.) and TPABr), reducing waste emissions and enhancing resource utilization efficiency. The synthesized ZSM-5 had a specific surface area of 455.675 m2g-1, pore volume of 0.284 cm3g-1, and pore diameter of 2.496nm. The influence of various factors on the morphology and crystallinity of ZSM-5 was investigated, resulting in the production of ZSM-5 with higher specific surface area and pore volume. Adsorption experiments showed that WU-ZSM-5 exhibited a removal efficiency of 85% for ammonia nitrogen (NH4+-N(aq.)), validating its effectiveness in coal chemical wastewater purification. The mother liquor recycling technology enabled zero-emission utilization of solid waste resources and improved the utilization rate of alkali and template to 90%. These results demonstrate the potential application of the developed method in the efficient treatment of coal chemical wastewater.

Optimization of on-site wastewater treatment efficiency and recovery based on nutrient mobility and adsorption kinetics modelling using HYDRUS-2D coupled with PHREEQC

A closed-loop on-site wastewater treatment system (OWT) was studied comprising steps of septic tank to remove organics (Biological Oxygen Demand (BOD)), biofiltration clarifier for biological removal of nitrogen (N), phosphorus (P) and BOD, reactive Polonite® filter for chemical adsorption and precipitation removal of dissolved P, and tidal flow constructed wetland (TFCW) sand filter for polishing the effluent to low P and N effluent Swedish standards. The field experimental data that have been used to optimize TFCW design in the numerical modelling using HYDRUS-2D coupled with and without PHREEQC indicated that the adsorption efficiency of the reactive Polonite® adsorbent was nearly double to that obtained in TFCW sand filters for PO4-P (95 %) and Total-P (85 %) removal in summer at a high temperature range (15.4–18.8 °C) and pH range (9.9–10.8). The weaker PO4-P (53 %) and Total-P (25 %) removal efficiency in winter was due to a low temperature (1.5–8.1 °C) and low pH (7.2–7.9). This decrease in pH was attributed to salinity in the domestic wastewater and dilution of rainwater. Modelling results revealed that the transport mechanisms and rate of P adsorption kinetics in the TFCW sand filters enhanced with calcium and iron flow from chemical dissolution in the preceding Polonite® adsorbent was increased with the increase in temperature. However, the P adsorption was less sensitive at high ferrihydrite (Fe(OH)3) dose, suggesting limited effects of cations dissolution and abundance of metal oxides and hydroxide ions at the mineral surface for anions exchange with phosphate for surface complexation. The strategy of combining field data and modelling provided valuable insights for assessing adaptability and optimizing TFCW design under variable fluxes and scenario effects of insulated/uninsulated and dilution by rainwater in cold-climate regions.

Electrochemical Hydrogen Peroxide Generation and Removal of Moxifloxacin by Electro-Fenton Process

In this study, the removal of moxifloxacin, an antibiotic of the fluoroquinolone group, from aqueous solutions was investigated using the electro-Fenton process. As the efficiency of the electro-Fenton process is highly dependent on the amount of H2O2 produced during process, the formation of H2O2 under acidic conditions was also investigated. In this context, the effects of applied current, cathode type and O2 flow rate on H2O2 production were investigated using boron-doped diamond anode. The highest H2O2 production was achieved using the boron-doped diamond anode and the graphite felt cathode. In addition, the optimum conditions for the applied current and oxygen flow rate for H2O2 production were determined to be 0.25 A and 0.1 L min−1, respectively. The effects of applied current and Fe2+ concentration in the electro-Fenton process on the removal of moxifloxacin were investigated. It was found that the moxifloxacin removal rate increased with increasing applied current. The highest H2O2 accumulation was observed at 0.25 A applied current, and moxifloxacin removal also reached 93.6% after 60 min. The moxifloxacin removal rate reached the highest value at Fe2+ concentration of 0.01 mM. This study provides promising results for the efficient treatment of moxifloxacin-containing wastewater by the electro-Fenton process without the addition of H2O2 using boron-doped diamond anode anode and graphite felt cathode.

A bio-based strategy for efficient industrial wastewater treatment using TiO2 photocatalysis

A bio-based strategy for efficient industrial wastewater treatment using TiO2 photocatalysis

Advanced microcrystalline nanocellulose-based nanofiltration membranes for the efficient treatment of wastewater contaminated with cationic dyes

Advanced microcrystalline nanocellulose-based nanofiltration membranes for the efficient treatment of wastewater contaminated with cationic dyes