Sewage Treatment Research Articles

Synergistic interaction of S-type heterojunction and sulfur vacancies in g-C3N5@Sv-ZnIn2S4 composites: Simultaneous promotion of complete 2,4-dichlorophenol mineralization and Cr(VI) reduction

Constructing efficient heterojunction photocatalysts is an effective measure for degrading pesticides and reducing heavy metals. In this study, g-C3N5@Sv-ZnIn2S4 (g-C3N5@Sv-ZIS) composite with large specific surface area has been successfully prepared by a simple low-temperature water bath method. The g-C3N5@Sv-ZIS composite showed complete mineralization of 2,4-dichlorophenol (2,4-DCP) and reduction of Cr(VI) within 60 min. The results of electron spin resonance spectroscopy, photoelectrochemical characterization, and energy band structure calculations indicated the formation of an S-type heterojunction at the interface of g-C3N5 and Sv-ZIS. In situ XPS analysis showed the transfer of photogenerated charges from g-C3N5 to Sv-ZIS. The molecular structure of 2,4-DCP was analyzed using frontier molecular orbital and electrostatic potential calculations. The possible degradation pathways of 2,4-DCP were proposed based on liquid chromatography– mass spectrometry results. Biotoxicity simulations of the intermediates revealed decreased toxicities. Furthermore, The kinetic rate constant of CZSv-200 for degrading 2,4-DCP and Cr(Ⅵ) in deionized water was approximately 2.20, 3.10 and 2.46, 4.03 times higher than that in lake and sewage plant water, respectively. The composites designed in this study provide reliable theoretical support for the removal of composite pollutants.

Electric energy consumption (EEC) in groundwater-based drinking water supply systems: analysis and comparison of seven Italian case studies

ABSTRACT Drinking water and wastewater services depend on energy: electric energy consumption (EEC) of this sector amounts to 2–3% of global EEC. The attention of the scientific community and of water utilities about this topic is focused on energy optimization of wastewater treatment plants and pumping stages in drinking water supply systems (DWSSs). However, because of increasingly stringent regulations and because of more and more extended water-source pollution, the need for ‘unconventional’ drinking water treatment systems, which are very energy-intensive, will bring treatment to be a key factor in this scenario. Analyzing EEC in seven full-scale DWSSs, we wanted to control EEC in every single stage of the DWSS (withdrawal, drinking water treatment plant (DWTP) and distribution) and to identify opportunities for reducing energy consumption in DWSS, with a special focus on each drinking water treatment process. The most energy-intensive unconventional treatment turns out to be membrane filtration by reverse osmosis (for which specific consumption per cubic meter of pumped water is equal to 0.243 Wh/m3), whereas the most energy-intensive conventional treatment turns out to be air oxidation (specific EEC from 0.012 to 0.087 kWh/m3). The main strategies for energy conservation can be applied both in management and in the design phase.

Recognizing the relevance of non-radical peroxymonosulfate activation by co-doped Fe metal-organic framework for the high-efficient degradation of acetaminophen: Role of singlet oxygen and the enhancement of redox cycle

A bimetallic MOF derivative consisting of Fe and Co (Fe/Co2-MOF) by Co-doping MIL-101(Fe) was successfully synthesized for peroxymonosulfate (PMS) activation in acetaminophen (N-Acetyl-Para-Amino-Phenol, APAP) degradation. The presence of Co significantly accelerated the transfer of electrons due to the synergistic effect between Fe and Co bimetallic sites. Specifically, the reaction rate constant of APAP in the Fe/Co2-MOF + PMS system was three orders of magnitude higher than that of MIL-101(Fe) alone and 90 times higher than that of the MIL-101(Fe) + PMS system, respectively. At room temperature, 100 % of the APAP was degraded in 15 min with a Fe/Co2-MOF concentration of 0.05 g/L and a PMS concentration of 0.8 mmol/L across a wide pH range from 3 to 9. High-valence metal species (CoIV and FeIV) and electron transfer-dominated nonradical processes were responsible for the APAP degradation. Although singlet oxygen (1O2) was identified as the main active species in our study, the relative contribution of 1O2 was negligible. The catalytic performance was particularly notable in the practical implementation of hospital sewage treatment. However, it is still urgent to seek ways to relieve cobalt leaching of Fe/Co2-MOF. This strategy of Co-doping provides a clear illustration of modulating MIL-101(Fe) ultimately maximize their catalytic efficiency in PMS activation for water purification.

Shining a Light on Sewage Treatment: Building a High-Activity and Long-Lasting Photocatalytic Reactor with the Elegance of a “Kongming Lantern”

Photocatalysis is a promising technology for efficient sewage treatment, and designing a reactor with a stable loading technique is crucial for achieving long-term stability. However, there is a need to improve the current state of the art in both reactor design and loading techniques to ensure reliable and efficient performance. In this study, we propose an innovative solution by employing polydimethylsiloxane as a bonding layer on a substrate of 3D-printed polyacrylic resin. By means of mechanical extrusion, the active layer interacts with the bonding layer, ensuring a stable loading of the active layer onto the substrate. Simultaneously, 3D printing technology is utilized to construct a photocatalytic reactor resembling a “Kongming Lantern”, guaranteeing both high activity and durability. The reactor exhibited remarkable performance in degrading organic dyes and eliminating microbes and displayed a satisfactory purification effect on real water samples. Most significantly, it maintained its catalytic activity even after 50 weeks of cyclic degradation. This study contributes to the development of improved photocatalysis technologies for long-term sewage treatment applications.

Carbon emission prediction and reduction analysis of wastewater treatment plants based on hybrid machine learning models

Accurate accounting and prediction of carbon emissions from sewage treatment plants is the basis for exploring low-carbon sewage treatment plants and measures to reduce pollution and carbon emissions. This study proposes a hybrid prediction framework based on machine learning, which integrates multiple algorithms and has strong adaptability and generalization ability. The prediction framework uses Pearson correlation coefficient to select feature values, constructs a combined prediction model based on the selected features using support vector machine (SVR) and artificial neural network (ANN), and optimizes the SVR model parameters and structure using Gray Wolf Optimization (GWO) algorithm. The results show that the model has stronger prediction performance compared with other prediction models, with a mean absolute percentage error (MAPE) of 0.49% and an R2 of 0.9926. In addition, this study establishes six future development scenarios based on historical data trends and policy outlines, which provide recommendations for the development of carbon emission reduction measures for wastewater treatment plants. This study can provide a reference for exploring efficient carbon management and achieving carbon neutrality in wastewater treatment plants.

Development of a wastewater treatment system contaminated with Cr (VI) through vegetable biomass modified with TIO2

Development of a wastewater treatment system contaminated with Cr (VI) through vegetable biomass modified with TIO2

Enhanced nutrients removal from low C/N ratio rural sewage by embedding heterotrophic nitrifying bacteria and activated alumina in a tidal flow constructed wetland

Rural sewage treatment facilitates nitrogen and phosphorus removal yet can be costly. To address this challenge, a cost-effective embedding material mainly consisting of heterotrophic nitrifying bacteria, activated alumina (AA), and a solid carbon source (HPMC) was applied to a tidal flow constructed wetlands (TFCWs); aimed at stable nitrogen and phosphorus removal under low carbon-to-nitrogen (C/N) ratios. The TFCWs could be shortened to 16 d of startup duration time compared with the control group; and improved the ammonia nitrogen (NH4+-N), total nitrogen (TN), and total phosphorus (TP) removal efficiencies to 98 %, 93 %, and 68 %, respectively. Also, effluent NH4+-N, TN, and TP in the enhanced TFCWs could be stable at 0.52 ± 0.18, 1.23 ± 0.45, and 0.75 ± 0.25 mg/L, respectively. Microbial community analysis revealed that AA and HPMC were enriched Pseudomonas sp., which potentially accelerated the NH4+-N assimilation pathway and phosphate biological removal. Embedding materials-TFCWs can provide new solutions for integrated rural sewage technology.

A systematic review on the occurrence and removal of microplastics during municipal wastewater treatment plants

This study uses a systematic review of Scopus, Web of Science, and ScienceDirect databases to investigate the removal rate of microplastics (MPs) at various stages of municipal wastewater treatment plants (WWTPs). In this context, 25 articles were included, which investigated 54 WWTPs. Results showed that the overall removal efficacy of MPs in studied WWTPs is about 88.1 (± 18.8) percent. The contribution of preliminary, primary, secondary, tertiary, and disinfection treatment in the removal of entry MPs are 37.4% (± 24), 62.7% (± 20.8), 63.7% (± 24.8), 62.8% (± 29.5), and 12.5% (± 15.7) (mean (± SD)), respectively. The critical aspects about MPs occurrence in WWTPs influent were summarized and on average 2267.2 (± 5376.4) MPs particles per liter (P/L) were present with a considerable wide range of 0.28 to 31400 P/L. In the next section, details about frequent shape (i.e., spherical (beads, pellets, granules), lines (filaments, fibers), films, fragments, and foams) of MPs in influent and effluent of included WWTPs and their removal efficacy during treatment steps are given. Finally, this study highlights future challenges in MP removal and suggests key areas for further research, such as improving treatment efficiency and understanding MP characteristics.

Bacterial Bioaerosol at Sewage Treatment Plant in Delhi, India: Characterization and Site-Specific Associations

Bacterial Bioaerosol at Sewage Treatment Plant in Delhi, India: Characterization and Site-Specific Associations

Unveiling electron transfer and radical transformation pathways in coupled electrocatalysis and persulfate oxidation reactions for complex pollutant removal

The degradation of multiple organic pollutants in wastewater via advanced oxidation processes might involve different radicals, of which the types and concentrations vary upon interacting with different pollutants. In this study, electrochemical activation of peroxymonosulfate (E/PMS) using advanced activated carbon cloth (ACC) as electrode was applied for simultaneous degradation of mixed pollutants, e.g., metronidazole (MNZ) and p-chloroaniline (PCA). 92.5 % of MNZ and 91.4 % of PCA can be degraded at the cathode and anode at a low current density and PMS concentration, respectively. The rate constants for the simultaneous removal of MNZ and PCA in the E/PMS/MNZ(PCA) system were 118 times and 6 times higher than those in the sole PMS system, and 2.5 times and 1.6 times higher than those in the E/Na2SO4/MNZ(PCA) system, respectively. Different electrochemical characteristics, EPR spectra and radical quenching tests verified that the degradation of MNZ and PCA in the optimal system proceeded primarily through non-radical-dominated oxidation, involving electron transfer and 1O2 effect. The system also exhibited low energy consumption (0.215 kWh/m−3·order−1), broad operational pH range, excellent removal efficiency for water matrix, and low by-products toxicity, indicating its strong potential for practical applications. The ACC, with its super stable, low cost, and electrochemical activity, make it as a promising materials applicable in the E/PMS system for degradation of multiple pollutants. The study further elucidated the mechanism of pollutant interaction with electrode materials in terms of radical and non-radical transformation, providing fundamental insight into the application of this system for treatment of complex wastewater.

Nanofiber aerogel with layered array with structure coupled photothermal/magnetothermal effect for continuous seawater desalination

The solar evaporation is susceptible to intermittent solar irradiation as well as salt crystallization deposition on the surface severely limits the evaporation efficiency. In this work, subject to inspiration of the transpiration, groove array structure and antifouling performance of banana leaves, a multifunctional photothermal/ magnetothermal coupled three-dimensional(3D) aerogel evaporator with layer-by-layer array structure was prepared by blow-spun technology which can achieve mass produced. The unique super hydrophilic vertical array structure has multi-scale high-efficiency water transport channels and the SnSe-Fe3O4 evaporation layer realizes super hydrophobic self-cleaning and excellent photothermal and magnetothermal conversion performance, which can achieve all-weather seawater desalination. The vertical array structures facilitate the reflection and refraction of light and promote the seawater convection and salt crystals absorption coupling. It could improve the photothermal conversion efficiency and salt resistance of the evaporator. Which resulted in an evaporation rate of 2.53 kg m−2h−1 under 1 sun, with solar energy conversion efficiency of 105 % and the evaporation rate is about 4.54 kg m−2h−1 at a magnetic field. Furthermore, it could purify organic pollutants in industrial wastewater and use waste heat to generate electricity. This evaporator provides a new economical and environmentally friendly solution for seawater desalination and sewage treatment.

Preparation of a Map of Potential Areas For the Installation of a Sewage Treatment Plant in the Porto Murtinho/MS Region

Objective: The main objective is to prepare a thematic map to identify potential areas for the installation of a Sewage Treatment Station (ETE). Theoretical Framework: This study addresses the importance of selecting locations for the installation of ETEs, which prioritize environmental and social aspects, in which geotechnologies are presented as valuable tools for efficient and integrated analysis. Method: The methodology of this research was based on the acquisition and processing of geospatial and environmental data, complemented by the generation of thematic maps such as watercourses, areas subject to flooding, roads, land use and occupation, slope, soils and distances from the urban perimeter. Data integration through map algebra was performed in the QGIS software, in addition, WRPLOT View was used for the directional analysis of the winds in Porto Murtinho/MS. Results and Discussion: The results of this study indicate that the areas with the greatest potential for installation are mostly located within 1 (one) kilometer of the urban perimeter security strip. The analysis of the prevailing winds revealed that they form a corridor in the north/south direction, suggesting that the regions east of the city are more suitable for the implementation of the treatment system. Research Implications: The multifaceted approach, considering environmental and operational factors, makes it possible to identify suitable areas for ETEs. Originality/Value: This study was developed, highlighting that limiting factors are essential in identifying areas unsuitable for installing the structure, while non-limiting maps are essential for classifying the installation potential.

Enhanced cadmium (Cd2+) removal from wastewater using integrated inclined plate settler and composite adsorbent coating

Bottlenecks inherent in batch and column adsorption configurations have impeded the implementation of the adsorption technique in large-scale wastewater treatment systems. This study mainly aimed to develop an innovative wastewater treatment prototype that integrates inclined plate settlers (IPS) and composite adsorbent coating (CAC). The objective is to enable the removal of Cd2+ from aqueous solutions in a continuous setup, thereby enhancing its practicality for large-scale applications. The combined IPS-CAC system was optimized at various angle of inclination (θ), influent flow rate (Q) and adsorbate initial concentration (Co) using the Box–Behnken Design (BBD) of the Response Surface Methodology (RSM). At optimized operating parameters (θ = 45°, Q = 5 ml/min and Ci = 1.87 mg/L) the IPS-CAC Cd2+ predicted (R2 = 0.9926) and experimental removal efficiencies were 75.8% and 69.7 ± 4.67%, respectively. The IPS-CAC breakthrough adsorption capacity was 9.6 mg/g. Comparing IPS-CAC performance with a tank without plates and IPS with plain plates, the Cd2+ removal efficiencies were 2.4 ± 0.1% and 4.6 ± 1.1%, respectively, confirming the synergistic effect of IPS and CAC. Additionally, breakthrough curves were acquired for various flow rates, cadmium influent concentrations, and plate inclination angles. Only a 10% decline in the removal effectiveness (from 69.7 to 59.7%) of the CAC after three adsorption–regeneration cycles was observed, indicating its stability for heavy metal removal. The results underpin the potential of using IPS-CAC for industrial wastewater treatment and enhancing the use of adsorption on a larger scale.

Toxicity Risks Associated With the Beta-Blocker Metoprolol in Marine and Freshwater Organisms: A Review.

The detection of pharmaceuticals in aquatic ecosystems has generated concern for wildlife and human health over the past several decades. β-adrenergic blocking agents are a class of drugs designed to treat cardiovascular diseases and high blood pressure. Metoprolol is a second-generation β1-adrenergic receptor inhibitor detected in effluent derived from sewage treatment plants. Our review presents an updated survey of the current state of knowledge regarding the sources, occurrence, and toxicity of metoprolol in aquatic ecosystems. We further aimed to summarize the current literature on the presence of metoprolol in various classes of aquatic species and to consider the trophic transfer of these contaminants in marine mammals. The biological impacts of metoprolol have been reported in 20 aquatic organisms, with a primary focus on cardiac function and oxidative stress. Our review reveals that concentrations of metoprolol that cause toxicity in aquatic species are above levels that are typical of marine and freshwater environments. Future studies should investigate the effects of metoprolol at lower concentrations in aquatic organisms. Other recommendations include (1) a further focus on noncardiac endpoints, because computational assessments of currently available molecular data identify gonadotropins, vitellogenin, collagen, and cytokines as potential targets of modulation, and (2) development of adverse outcome pathways for cardiac dysfunction in aquatic species to improve our understanding of molecular interactions and outcomes following exposure. As the next generation of β-blockers is developed, continued diligence is needed for assessing environmental impacts in aquatic ecosystems to determine their potential accumulation and long-term effects on wildlife and humans. Environ Toxicol Chem 2024;00:1-14. © 2024 SETAC.

Comprehensive Evaluation of Urban Renewal Based on Entropy and TOPSIS Method: A Case of Shandong Province

This study offers a comprehensive evaluation of urban renewal efforts in Shandong Province, China, by employing the entropy method combined with the Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS). An evaluation index system was constructed to assess the weights of key factors influencing urban renewal, including the renovation of old residential areas, improvement in sewage treatment quality, development of sponge cities, adoption of clean heating, and enhancement of air quality. Analysis of 16 prefecture-level cities in 2019 reveals significant disparities in performance, with Jinan achieving the highest ranking due to notable improvements in infrastructure and environmental management. Meanwhile, other cities displayed varying levels of success, reflecting different developmental stages and capacities. The findings underscore the necessity for tailored strategies to optimize urban renewal outcomes, focusing on high-weight factors such as sewage treatment, clean heating, and residential renovation. This study provides actionable insights for policymakers, advocating adaptive renewal strategies that align with local contexts and encourage continuous innovation. The results highlight the importance of targeted policy interventions to enhance urban renewal quality across Shandong Province, promoting sustainable urban development and better living standards.

Experimental study on surface optimization of dosage in magnetic coagulation process for enhancing primary treatment of urban sewage

This work aims to investigate the minimum dosage required to achieve optimal removal of carbon, nitrogen, and phosphorus in the Chemical Enhanced Primary Treatment (CEPT) process using magnetic coagulation technology. A response surface methodology was adopted to generate multiple regression models to optimize the dosages of three types of coagulation, i.e., polyaluminum chloride (PAC), polyacrylamide (PAM), and magnetic medium Fe3O4 particles (MP), based on the removal rates of chemical oxygen demand (COD), ammonia nitrogen (NH3-N), and total phosphorus (TP). The results showed that the regression models could predict results well with actual engineering results. Compared to the traditional coagulation process, the synergistic enhancement of PAC+PAM+MP in the CEPT process significantly improved the treatment effects. Based on the COD removal rates, PAC performed better than MP, followed by PAM; likewise, for the NH3-N and TP removal rates, PAC outperformed PAM, followed by MP. The optimized PAC, PAM, and MP dosages were 135.87, 1.51, and 108.36 mg/L, respectively, reaching 92.27 % COD, 71.98 % NH3-N, and 91.33 % TP removal rates with less than 5 % errors compared to the experimental verification results. These optimization models offer a practical and cost-saving reference for enhancing the primary treatment effect on carbon, nitrogen, and phosphorus removal using PAC+PAM+MP.

Life-Cycle Analysis of Natural Treatment Systems for Wastewater (NTSW) Applied to Municipal Effluents

The objective of the described activity is to develop technologies or proposals that can be implemented within the cycle to enhance the relationship between climate change, water, energy, and food. The focus is on analyzing natural treatment systems for wastewater (NTSW) within the context of Macaronesia, considering factors such as life-cycle assessment (LCA), carbon footprint, impacts, and mitigation capacity. The analysis of real case data from the Canary Islands and Cape Verde will inform the development of appropriate technologies tailored to different areas and scales within Macaronesia. This work includes a comprehensive life-cycle analysis of the Santa Catarina (Cape Verde) NTSW. This analysis encompasses: (a) Inventory analysis of the construction phase: This involves the assessment of inputs and outputs associated with the construction of the NTSW, including materials, energy consumption, transportation, and waste generation. The maintenance and operation phases are then evaluated, with a focus on the ongoing maintenance and operation activities required for the NTSW, including energy consumption, water usage, chemical inputs (if any), labor, and equipment maintenance. (b) Finally, the impacts of the NTSW are evaluated. The environmental, social, and economic impacts generated by the NTSW are assessed. This includes an analysis of factors such as carbon emissions, water usage, land use, ecosystem impacts, human health effects, and economic costs. By conducting a comprehensive analysis of the Santa Catarina NTSW, the document aims to provide insights into the environmental performance and sustainability of the system. This information can then be used as a tool and experience of educational innovation for final-year undergraduate students to identify areas for improvement, develop mitigation strategies in the water sector, and inform decision-making processes regarding wastewater treatment technologies in Macaronesia. Furthermore, lessons learned from real case studies in the Canary Islands and Cape Verde can be applied to similar regions within the Macaronesia archipelago (IDIWATER project).

Efficient removal of organic matter and nitrogen from municipal wastewater in multi-module biochar filters for onsite wastewater treatment

ABSTRACT Biochar is a promising material for wastewater treatment. This study assessed multi-module biochar filters (MmBFs) as onsite wastewater treatment systems (OWTSs), comprising movable modules filled with biochar to remove chemical oxygen demand (COD), nitrogen, phosphorus, and Escherichia coli (E. coli) in wastewater. The MmBF treats wastewater sequentially through six modules: three aerobic modules (M1-M3) for organic matter oxidation and nitrification, two anoxic modules (M4-M5) for denitrification, and an additional module (M6) for the removal of faecal bacteria using biochar and bark. The experiments ran for 381 days using three identical MmBF pilots with two distinct sampling periods, conducted under conditions relevant to OWTSs using municipal wastewater as influent. Water samples were taken from the influent, final effluent, and effluent of each module to evaluate the removal efficiency of organic matter, nitrogen, phosphorus, and E. coli. During the second sampling period, the results showed a 95 ± 2.1% removal of COD, along with a substantial removal of total inorganic nitrogen (71 ± 6.6%). However, phosphate removal was limited (3.4 ± 30.4%). E. coli removal decreased from 2.63 ± 0.93 log10 removal in the first sampling period to 1.8 ± 0.73 log10 removal in the second sampling period. In summary, the MmBFs showed promising potential in treating organic matter, nitrogen, and E. coli, making it an alternative option for OWTS. However, further exploration is needed to assess long-term performance, micropollutant removal, and biological activities. Design enhancements, especially for phosphorus removal are necessary.

Study the Utilization of Biochar Derived from Sugarcane Waste to Enhance the Biogas Efficiency During the Anaerobic Digestion Process for Treating Pig Farm Wastewater

This experiment aims to study the use of biochar (Biochar, BC) from sugarcane trash through the pyrolysis process at different temperatures of 300, 400, 500, 600 and 700°C. Then add BC to the Anaerobic Digestion (AD) system of wastewater from pig farms, then analyze the characteristics of wastewater and the amount of biogas obtained before and after treatment and to study the characteristics of decomposition, the generation of biogas (Biogas) to the reduction of organic matter in wastewater (COD). From this experiment, it can be concluded that all 6 systems are producing biogas, such as: the normal system and the system with BC filling at different burning temperatures: 300, 400, 500, 600 and 700℃ in the amount of 0.4g into the system. .64, 46.13, 51.90 and 65.98% respectively. From the experiments of all systems, it is observed that the system filled with BC at a temperature of 700℃ is able to produce biogas the best because the high heating temperature will cause the electrons of the charcoal to break easily and cause more holes to be a place for microbes to grow well. A comparison of the conventional system and adding biochar with the same amount but different temperature into the sewage treatment system without using air can be concluded that the conventional system is the generation of biogas is still low efficiency and the system of adding BC at the temperature of 300, 400, 500, 600℃ in the same amount. Notice that the generation of biogas is higher in order and the filling of BC at a temperature of 700℃ is able to produce biogas higher than other systems.

Visual Pollution of the Banks of the Tigris River in Baghdad City Capital of Iraq

The study titled "Visual Pollution of the Tigris Riverbanks in Baghdad City" consists of two main sections: the first section is dedicated to the theoretical framework, while the second section covers the practical aspect (field study). Specific areas of Baghdad were selected for this study due to the widespread presence of solid waste along the riverbanks. The importance of the study lies in the fact that visual pollution is one of the dangerous types of pollution that affects both human health and the environment. The study concluded that visual pollution along the Tigris River banks results from the impact of human activities spread linearly along the river, and the lack of environmental awareness among residents has negatively affected the river environment through the disposal of household and construction waste and the discharge of untreated wastewater from sewage treatment plants. The research recommends the importance of strict monitoring of human activities near the river, imposing financial penalties on violators of environmental standards, and working on rehabilitating and developing the riverbanks to make them attractive environments for residents, turning them into tourist and recreational areas that serve the city.