Water Treatment Processes Research Articles

Metadata and feature importance analyses of membrane capacitive deionization models: Is a water treatment artificial intelligence panacea possible?

Membrane capacitive deionization (MCDI) is an emerging technology for water purification and desalination. Artificial intelligence (AI) techniques using machine learning (ML) and deep learning (DL) have been widely applied to overcome the drawbacks of conventional numerical models in predicting effluent concentrations, an important parameter to estimate the energy consumption and degree of desalination of the MCDI process. However, despite the remarkable progress of these ML/DL models, relevant studies have only been conducted with limited datasets, leading to a substantial controversy regarding model accuracy. Therefore, in this study, we comprehensively evaluated the performances and applicability of multiple ML/DL models for MCDI using metadata (i.e., performance indices) and feature importance analyses. One MCDI dataset containing both constant-current and constant-voltage operations was reconfigured uniformly or unevenly depending on operation modes. Subsequently, six ML models and one DL model were used to execute the analyses using performance indices. Collectively, this study suggests that a perfect ML/DL model for the water treatment process may not exist, and understanding data types is as important as selecting appropriate models to build a data-driven AI model when process performance is greatly affected by specific input variables (i.e., current and voltage).

Comparative Evaluation of Boron Sorption Dynamics on Zeolites in Irrigation Waters: An Isothermal Modeling Approach.

Efficient boron removal from irrigation waters is crucial for sustainable agriculture, as elevated levels of boron can be toxic to many plants, limiting growth and crop productivity. In this context, the present study investigated the sorption equilibrium of boron using zeolites in two types of aqueous matrices: a synthetic solution containing only boron and natural irrigation waters. Through the application of various isothermal sorption models (Langmuir, Freundlich, Sips, Toth, Jovanovic, Temkin, Dubinin-Radushkevich, and Redlich-Peterson), the efficacy of zeolite for boron removal under controlled and real conditions was evaluated. The results indicated a notable difference in sorption behavior between the two matrices, reflecting the complexity and heterogeneity of interactions in the boron-zeolite system. In the synthetic solution, the Freundlich model provided the best fit (R2 = 0.9917), suggesting heterogeneous and multilayer sorption, while the Sips model showed high efficacy in describing the sorption in both matrices, evidencing its capability to capture the complex nature of the interaction between boron and zeolite under different environmental conditions. However, in natural irrigation waters, the Jovanovic model demonstrated the most accurate fit (R2 = 0.999), highlighting the importance of physical interactions in boron sorption. These findings underscore the significant influence of the water matrix on the efficacy of zeolite as a boron removal agent, emphasizing the need to consider the specific composition of irrigation water in the design of removal treatments. Additionally, the results stress the importance of selecting the appropriate isothermal model to predict boron sorption behavior, which is crucial for developing effective and sustainable treatment strategies. This study provides a basis for optimizing boron removal in various agricultural and industrial applications, contributing to the design of more efficient and specific water treatment processes.

Radiation-Induced Hydrogel for Water Treatment.

Along with serving as drug delivery sensors and flexible devices, hydrogels are playing pioneering roles in water purification. Both chemical and radiation methods can produce hydrogels, with the latter method gaining preference for its pure adducts. The water treatment process entails the removal of heavy and toxic metals (above the threshold amount), dyes, and solid wastes from industrial effluents, seawater, and groundwater, as well as sterilization for microorganism destruction. This review analyzed the different types of hydrogels produced by applying various radiations for water treatment. Particularly, we examined the hydrogels created through the application of varying levels of gamma and electron beam radiation from the electron gun and Co-60 sources. Moreover, we discuss the optimized radiation doses, the compositions (monomers and polymers) of raw materials required for hydrogel preparation, and their performance in water purification. We present and predict the current state and future possibilities of radiation-induced hydrogels. We explain and compare the superiority of one radiation method over other radiation methods (UV-visible, X-ray, microwave, etc.) based on water treatment.

Activated Carbon Prepared from Date Pits Using Microwave Heating

Activated carbon (AC) adsorption remains one of the most technically efficient water treatment processes. However, its high preparation cost, mainly due to energy-intensive methods, has led to research on developing efficient and cost-effective preparation methods using less expensive materials such as agricultural waste. The objective of our study was to use date pits for the preparation of AC that can be used for water treatment (Adsorption and elimination of dyes). For the activation process, a microwave radiation under steam method was employed. The AC prepared from date pits /H3PO4/carbonization 400°C using the steam-microwave radiation activation technique (radiation time: 15 minutes, power: 700W) demonstrated promising results. The adsorption tests show 80% removal rate of the reactive dye (Drimaren ROT CL-5B GR) from water. This study highlights the potential of date pits as a viable source for producing AC from bio-material. The obtained product was analysed by FTIR and MEB.

A review on the synergistic efficacy of sonication-assisted water treatment process with special attention given to microplastics

The rampant spread of microplastic pollution in both natural and industrial water bodies has emerged as a paramount environmental concern. Regrettably, conventional water treatment methods (e.g., adsorption, membrane filtration, coagulation-flocculation, and electrocoagulation, processes) have been discovered to be inadequately effective in tackling this issue. However, the advent of sonication-assisted water treatment technologies has shown great promise in curbing microplastic pollution. This review article expounds on the latest trends in sonication-assisted water treatment technologies for microplastic removal. A comparison between conventional water treatment methods and sonication-assisted procedures elucidates the pros and cons of each were conducted. Additionally, an exploration of various sonication-assisted techniques and their potent efficacy in removing microplastics was undertaken. Sonochemical, Sonoelectrochemical, Sonophotocatalytic, Sonofenton, and Sonoelectrocatalytic, may be used for microplastics (MPs) removal, it has been demonstrated that ultrasonic frequencies between 100 and 1000 kHz for the sonochemical process are more useful than frequencies below 20 kHz. Generally, sonication methods have good compatibility and attachment to other biological or physical processes and increase the cavitation-induced concentration of the reactive radical in the bulk phase. Also, When Fenton processes are combined with sonication, the number of ferrous ions present in the treated water decreases due to easy handling, quick degradation, and a wide pH range that can be used. The economic aspects are the biggest challenges in synergistic efficacy of sonication-assisted water treatment for microplastics mitigation. The paramount importance of continued research and development to refine and optimize sonication-assisted water treatment technologies for practical implementation was concluded.

Enhanced diclofenac abatement by ferrate in the presence of montmorillonite: Trapping in-situ formed Fe(III)

Ferrate (Fe(VI)) is an environmentally-friendly chemical oxidant employed in water and wastewater treatment. The effect of montmorillonite (MMT) on the abatement of diclofenac (DCF) by Fe(VI) was studied. Results indicate that the presence of 200 mg/L MMT enhanced the second-order rate constant for the reaction between DCF and Fe(VI) from 117 to 219 M-1 s-1 at pH 7.6, whereas no significant enhancement was observed for silicon dioxide and kaolinite. In-situ formed Fe(III) from Fe(VI) decay played important roles on the enhanced oxidation of DCF by Fe(VI). In addition, no enhancement was observed in phosphate buffer since phosphate could sequester Fe(III). A similar enhancement of DCF abatement by Fe(VI) in the presence of MMT can be observed using preformed Fe-MMT. Adsorbed Fe(III) which is present in the form of FeOOH can increase the layer spacing of MMT from 11.4 to 15.0 Å. In-situ formed Fe-MMT increases the oxidation efficiency of methylphenyl sulfoxide, a probe compound. Addition of 50 mg/L MMT during Fe(VI) oxidation can increase the yield of reactive high-valent iron intermediates (e.g., Fe(IV) and Fe(V)) by 43%. This work provides new insights into Fe(VI) application in pre-oxidation for the abatement of micropollutants in water treatment processes.

Trace Ce(III) boosted acidic peroxone (O3/H2O2) process for efficient water treatment: Essential role of oxalic acid complexation

The peroxone (O3/H2O2) process has long suffered from inefficient performance for water decontamination at acidic pHs. Herein, we find the evident capability of trace Ce(III) to boost the acidic peroxone process. In contrast to the negligible degradation (∼6% in 60 min) of oxalic acid (OA) as a recalcitrant compound in the O3/H2O2 system, efficient removal of OA (∼95 %) was achieved by introducing trace Ce(III) (0.30 µM). OA was identified as an effective ligand activating Ce(III) by forming the Ce(III)-OA complex, which served as the catalytic active component to accelerate the decomposition of O3 and H2O2 to produce •OH and promote the co-degradation of refractory pollutant atrazine and ibuprofen. The remarkable catalytic activity of trace Ce(III) for peroxone reaction resulted from the efficient interconversion of Ce(III/IV) relying on both the favorable electron transfer from the ternary Ce(III)-OA-hydroperoxo complex to O3 and the rapid reduction of Ce(IV) back to Ce(III) mainly by H2O2. Furthermore, the catalytic performance of Ce(III) for peroxone process outperformed Fe(II), Cu(II), and Co(II). This study puts forward an effective method to extrapolate the applicability of the peroxone (O3/H2O2) process to the acidic range and enlightens the development of Ce-catalyzed peroxone processes.

Total Quality Management in the Service Sector: A Case Study in a Water Supply Company

Objective: Analyze the benefits of adopting total quality in a water supply company, aiming to improve service quality and customer satisfaction. Theoretical Framework: A literature review was conducted as a basis for understanding the key concepts of TQM, the dimensions of service quality, and the essential elements for the successful implementation of TQM in the context of the analyzed company. Method: The research is classified as a case study with an applied qualitative approach. To achieve the proposed objectives, techniques such as documentary research, literature review, semi-structured interviews, and direct observation were used. Results: The analysis of the results demonstrated that the water supply company faces significant challenges regarding service quality. From the TQM approach, opportunities for improvement were identified in different areas of the organization, both in the reliability of the services' outcomes, including the water treatment process and maintenance of the distribution network, and in customer service. Research Implications: The research suggests that the water supply company should adopt TQM as a strategy to improve service quality, promote customer satisfaction, address internal challenges, and seek constant improvement. Originality/Value: The study explores the application of TQM in a public service context, providing practical guidance and insights to improve service quality in a water supply company, with implications that may extend to similar organizations seeking to enhance their services and processes.

Occurrence, efficiency of treatment processes, source apportionment and human health risk assessment of pharmaceuticals and xenoestrogen compounds in tap water from some Ghanaian communities

The occurrence of pharmaceuticals and xenoestrogen compounds (PXCs) in drinking water presents a dire human health risk challenge. The problem stems from the high anthropogenic pollution load on source water and the inefficiencies of the conventional water treatment plants in treating PXCs. This study assessed the PXCs levels and the consequential health risks of exposure to tap water from selected Ghanaian communities as well as that of raw water samples from the respective treatment plants. Thus the PXCs treatment efficiency of two drinking water treatment plants in the metropolises studied was also assessed. The study also conducted source apportionment of the PXCs in the tap water. Twenty six (26) tap and raw water samples from communities in the Cape Coast and Sekondi-Takoradi metropolises were extracted using SPE cartridges and analysed for PXCs using Ultra-fast-HPLC-UV instrument. Elevated levels of PXCs up to 24.79 and 22.02 μg/L were respectively recorded in raw and tap water samples from the metropolises. Consequently, elevated non-cancer health risk (HI > 1) to residential adults were found for tap water samples from Cape Coast metropolis and also for some samples from Sekondi-Takoradi metropolis. Again, elevated cumulative oral cancer risks >10−5 and dermal cancer risk up to 4 × 10−5 were recorded. The source apportionment revealed three significant sources of PXCs in tap water samples studied. The results revealed the inefficiency of the treatment plants in removing PXCs from the raw water during treatments. The situation thus requires urgent attention to ameliorate it, safeguarding public health. It is recommended that the conventional water treatment process employed be augmented with advanced treatment technologies to improve their efficacy in PXCs treatment.

Research on Ternary Composite Flooding Produced Water Treatment Process

This paper introduces the ternary composite drive technology and the characteristics of the technology. The characteristics of ternary composite flooding produced water were sorted out, and the characteristics of complex organic composition, poor biochemical treatment, high oil content, high suspended solids content, high viscosity and high emulsification degree were sorted out. Three ternary composite flooding produced water treatment processes were introduced. Under the condition of ensuring that the effluent meets the requirements of reinjection water, the advantages and disadvantages of the three processes are compared, and finally the third process flow is determined to be the optimal option. The process can not only effectively improve the treatment effect of ternary composite flooding produced water, but also overcome the shortcomings in the conventional process, improve the feasibility of the process and reduce the cost.

High performance Zn–Al LDH modified forward osmosis membrane with antibacterial, anti-membrane fouling, and photocatalytic degradation ability

Forward osmosis membrane has shown great potential in the fields of seawater desalination and sewage treatment. However, the concentration polarization phenomenon and membrane fouling in the water treatment process greatly reduce the water treatment performance and restrict its application. To address these challenges, we employed a pre-buried seed-in-situ growth method to facilitate the Zn–Al layered double hydroxide (Zn–Al LDH) growth on the thin nanofiber membrane, and use it as the support layer for the preparation of a Zn–Al LDH modified forward osmosis membrane. Studies have shown that the introduction of Zn–Al LDH significantly improves the water treatment efficiency of the forward osmosis membrane (In Al-DS mode, the water flux increased by 87.5 %, up to 50.50 LMH, with a low specific salt flux of 0.13 g L−1). It also exhibits exceptional antibacterial, anti-membrane fouling, and photocatalytic degradation properties. This research presents a novel approach for the development of advanced high-efficiency forward osmosis membranes.

Pengaruh Konsentrasi Koagulan Terhadap Proses Pengolahan Air Di PDAM Surya Sembada Kota Surabaya

Coagulation is one of the processes of water treatment by the addition of chemicals, the purpose of which is to bind particles like particles or dissolve so that they clump. Coagulation concentration definitely affects the coagulation process carried out. In addition, the addition of coagulation also affects the water produced for distribution. Testing of the impact of coagulant concentrations on raw water treatment processes has been carried out on the PDAM Surya Sembada Surabaya. The use of laboratory testing methods is done to see the water quality when using different coagulants. The results of the analysis obtained that the difference in the concentration of coagulants has an influence on the process of water treatment, this is due to several factors that support the existence of variation in the use of the coagulation concentration.

Optimization of the concentration of ozone generated by DBD using PSO algorithm for water treatment process

The water treatment process with ozone is influenced by various operating parameters and environmental factors that can impact its efficiency. In this study, experiments were conducted using a Venturi pumping frame to investigate the effects of three controllable variables: oxygen flow height, applied voltage level, and water flow rate. The tests aimed to develop a mathematical model that accurately represents the relationship between these input variables and the resulting ozone concentration in the treated water. The experimental data was analyzed using the MODDE 5.0 software, a specialized application for statistical modeling and design of experiments. By fitting the data to appropriate model equations, a mathematical model was obtained that quantifies the influence of each variable and their interactions on the ozone concentration response. To optimize the process performance, a particle swarm optimization (PSO) algorithm was employed to extract the best-fit parameters for the mathematical model. PSO is a computational technique inspired by the social behavior of bird flocks or fish schools, utilizing a population of candidate solutions that evolve iteratively to converge on the global optimum solution. In this case, PSO searched for the model parameter values that minimized the error between predicted and experimentally measured ozone concentrations, rapidly converging to an accurate solution. The optimized mathematical model enables predicting the ozone concentration under any combination of oxygen flow height, voltage, and water flow rate within the experimental range. This predictive capability facilitates identifying the optimum operating conditions to maximize ozone concentration, thereby enhancing the efficiency of the water treatment process. The model serves as a valuable tool for process control, monitoring, and optimization, ensuring consistent treatment quality while minimizing resource consumption and operational costs.

Production of sludge biochar by steam pyrolysis and acid treatment: Study of the activation mechanism and its impact on physicochemical properties

This study addresses the preparation of sludge biochar through a procedure that combines steam pyrolysis in a wide range of temperature (500–900 ºC) and acid treatment with HCl (performed before or after the pyrolysis). The acid washing after the pyrolysis maximizes BET surface area due to pore unblocking, thus making visible the pore structure generated. The drawback of the acid washing is the lower yield obtained (compared to the acid pretreatment), as well as the loss of the magnetic properties of sludge biochar. The acid pretreatment requires temperatures above 700 ºC to have a beneficial effect, due to the occurrence of additional reactions of the incorporated HCl with sludge constituents. The pretreatment results in materials with a high degree of microporosity. Among the reactions favoured, of interest is the development of magnetite in the whole temperature range. The activation protocol used in this study (especially the procedure that includes the acid pretreatment) is effective to generate biochar with magnetic properties through the transformation of the Fe introduced during the water treatment process, without adding a source of Fe. The presence of magnetite is an advantage for the reuse of sludge biochars in wastewater treatment.

Mo-BiVO4 Photocatalytically Modified Ceramic Ultrafiltration Membranes for Enhanced Water Treatment Efficiency.

This study highlights the effectiveness of photocatalytically modified ceramic ultrafiltration (UF) membranes in alleviating two major drawbacks of membrane filtration technologies. These are the generation of a highly concentrated retentate effluent as a waste stream and the gradual degradation of the water flux through the membrane due to the accumulation of organic pollutants on its surface. The development of two types of novel tubular membranes, featuring photocatalytic Mo-BiVO4 inverse opal coatings, demonstrated a negligible impact on water permeance, ensuring consistent filtration and photocatalytic efficiency and suggesting the potential for maintaining membrane integrity and avoiding the formation of highly concentrated retentate effluents. Morphological analysis revealed well-defined coatings with ordered domains and interconnected macropores, confirming successful synthesis of Mo-BiVO4. Raman spectroscopy and optical studies further elucidated the composition and light absorption properties of the coatings, particularly within the visible region, which is vital for photocatalysis driven by vis-light. Evaluation of the tetracycline removal efficiency presented efficient adsorption onto membrane surfaces with enhanced photocatalytic activity observed under both UV and vis-light. Additionally, vis-light irradiation facilitated significant degradation, showcasing the versatility of the membranes. Total Organic Carbon (TOC) analysis corroborated complete solute elimination or photocatalytic degradation without the production of intermediates, highlighting the potential for complete pollutant removal. Overall, these findings emphasize the promising applications of Mo-BiVO4 photocatalytic membranes in sustainable water treatment and wastewater remediation processes, laying the groundwork for further optimization and scalability in practical water treatment systems.

The effectiveness and feasibility of ball-milled powdered activated carbon (BPAC) for removal of organic pesticides in conventional drinking water treatment process

In the conventional drinking water treatment process (CDWTP), powdered activated carbon (PAC) is commonly used for removing organic pesticides, or other organic contaminants. However, the hydraulic retention time (HRT) in CDWTP is insufficient for fulfilling PAC adsorption equilibrium to realize its full capacity. This study examined the adsorption kinetics, adsorption thermal dynamics, and removal efficiency for six organic pesticides using the ball-milled PAC (BPAC) with varying particle sizes in CDWTP. Based on the experiments with the pesticides of atrazine, diazinon, dimethoate, fenitrothion, isoproturon and thiometon, the results indicated that as the particle size reduced from around 38 μm for the commercial PAC to 1 μm for the BPAC, the adsorption rates for hydrophobic pesticides increased up to twentyfold. Diffusional adsorption from the bulk solution to the external PAC surface is the most likely predominant mechanism. This could allow a sufficient pesticides’ adsorption within the limited HRT and to achieve a great depth removal of these toxic compounds. However, the addition of BPAC with a diameter of 1 μm was observed to significantly increase residual particles in treated water after the conventional treatment process. With a further systematic evaluation of both adsorption rate and particle penetration, a particle size of around 6 μm BPAC was considered a practical compromise between the adsorption rate and particle penetration for real application. Results from five surface waters of different water quality indicated that, compared to commercial PAC, application of 6 μm BPAC could achieve up to a 75% reduction in adsorbent dosage while maintaining around the same pesticide removal efficiencies. Additionally, thermodynamic analyses suggest that adsorption of these pesticides could be enthalpically or entropically driven depending on the degree of pesticide hydrophobicity.

Combined Effects of Banana Peels and Pith as Dual Natural Plant-Based Coagulants for Turbidity Removal

Combined Effects of Banana Peels and Pith as Dual Natural Plant-Based Coagulants for Turbidity Removal

Photocatalytic activation of sodium percarbonate by C3N5/C2N3 homojunction for rapid water purification: Efficient electron transfer of built-in electric field

The sodium percarbonate (SPC) activation by photogenerated electron from metal-free semiconductors is a potential advanced oxidation process in water treatment. C2N3, a novel CxNy material, was used to construct a nonmetallic homojunction catalyst via loading C3N5. The C3N5/C2N3 homojunction catalyst was used to photocatalytic activate SPC to degrade acetaminophen (AP), sulfamethoxazole, tetracycline, oxytetracycline and acyclovir. The CN-2/SPC/Vis system can completely remove AP within 20 min at 15 °C, and achieve excellent removal rate in a wide pH range. Its reaction rate constant was 24 times higher than that of C3N5/C3N4/SPC/Vis system. The CN-2/SPC/Vis system showed outstanding removal efficiency in tap and lake water. Notably, CN-2 was prepared as a photocatalytic suspension sponge and exhibited superior practicability in secondary effluent simulation experiment. CN-2 sponge can completely degrade AP within 50 min. The dominant active species for AP removal were h+, •O2− and 1O2. DFT calculations and electrochemical experiments demonstrated that the built-in electric field of nonmetallic homojunction accelerated the carrier separation, and more photogenerated electrons activated SPC to generate ROS. This work provides new insights into the construction of heterojunction in photocatalytic system and reveals the application potential of homojunction in wastewater purification.

The coagulation process for enveloped and non-enveloped virus removal in turbid water: Removal efficiencies, mechanisms and its application to SARS-CoV-2 Omicron BA.2

The coagulation process has a high potential as a treatment method that can handle pathogenic viruses including emerging enveloped viruses in drinking water treatment process which can lower infection risk through drinking water consumption. In this study, a surrogate enveloped virus, bacteriophage Փ6, and surrogate non-enveloped viruses, including bacteriophage MS-2, T4, ՓX174, were used to evaluate removal efficiencies and mechanisms by the conventional coagulation process with alum, poly‑aluminum chloride, and ferric chloride at pH 5, 7, and 9 in turbid water. Also, treatability of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a recent virus of global concern by coagulation was evaluated as SARS-CoV-2 can presence in drinking water sources. It was observed that an increase in the coagulant dose enhanced the removal efficiency of turbidity and viruses, and the condition that provided the highest removal efficiency of enveloped and non-enveloped viruses was 50 mg/L of coagulants at pH 5. In addition, the coagulation process was more effective for enveloped virus removal than for the non-enveloped viruses, and it demonstrated reduction of SARS-CoV-2 Omicron BA.2 over 0.83-log with alum. According to culture- and molecular-based assays (qPCR and CDDP-qPCR), the virus removal mechanisms were floc adsorption and coagulant inactivation. Through inactivation with coagulants, coagulants caused capsid destruction, followed by genome damage in non-enveloped viruses; however, damage to a lipid envelope is suggested to contribute to a great extend for enveloped virus inactivation. We demonstrated that conventional coagulation is a promising method for controlling emerging and re-emerging viruses in drinking water.

IoT-Enabled Water Quality Monitoring and Alum Dose Determining System

The water treatment process involves a series of physical, chemical, and biological techniques and methods designed to remove contaminants, impurities, and undesirable substances from raw or untreated water to make it safe, clean, and usable. Adverse weather conditions, such as rainy seasons and floods, present significant challenges, and difficulties to the water treatment process. Alum is mainly used for reducing the turbidity of the water in the treatment process. In Sri Lanka, all water treatment plants use the Jar Test to determine the Alum dosage manually. They conduct Jar Tests to measure raw water quality in their laboratories. The Alum addition valve is set to a pre-determined quantity and the value is decided based on the experience of the technicians. Since there is no specific formula, the presence of an experienced technician is required to determine alum dosage using the Jar test. Thus, this study intends to propose an automated system for determining the optimum Alum quantity to be added to a given raw water sample. This is achieved by designing an Internet of Things (IoT)-enabled sensing device for measuring the water quality, which feeds data to a Machine Learning Model trained to predict the Alum quantity to be added. The task of the Machine learning model is to identify the pattern of raw water parameters and Alum dosage. By doing this, a could be provided a guideline for determining alum dosage instead of a manual Jar test and removed the necessity of experienced technician support always. A user-friendly web interface will allow the operators to customize the parameters according to the requirement and display a detailed analysis report. The predetermined quantity of Alum is transmitted to the output Alum adding value, to enhance its performance as an automated control rather than doing the addition process manually. This is a conceptual study on how to determine the Alum dosage using Raw water parameters and past experiment results.