Sewage Treatment Research Articles

WASTEWATER GLOBAL POLLUTION INDEX AS AN INDICATOR IN ASSESSING THE QUALITY OF THE EFFLUENT FROM THE ARAD MUNICIPAL TREATMENT PLANT

The main aim of the present study was to characterize the quality of the sewage leaving the Arad Municipal Wastewater Treatment Plant and highlight the emergence and importance of water reclamation, recycling, and reuse as vital components in integrated aquatic resources management for further reuse. The sewer quality assessment was performed for the period 2018 - 2021. For this purpose, the Global Pollution Index (𝐼􀯀􀯉 ∗ ) was used to determine the degree of pollution of the wastewater influent and effluent from the Arad treatment plant during the mentioned period. These results on the quality of incoming and outgoing sewerage can contribute to developing a management plan for protecting and properly managing water resources.

High Salinity Tolerance of Zn-Rich g-C3N4 in the Photocatalytic Treatment of Chlorophenol Wastewater

Organic saline wastewater has become a concern in recent decades due to its resistance to biological treatment and potential harm to municipal wastewater treatment plants. While photocatalytic methods have been used for treatment, they often lead to catalyst deterioration. The use of salt-tolerant catalysts presents a viable solution for treating organic saline wastewater. In this study, a Zn-rich g-C3N4 was synthesized, demonstrating excellent performance in removing 2,4-DCP and its derivatives from saline wastewater. More than 75.6% of 2,4-DCP was effectively removed with the addition of Zn-rich g-C3N4, nearly doubling the removal rate compared to pure g-C3N4 and those doped with Co, Ag, Mo, and Bi. Notably, the removal efficiency of 2,4-DCP slightly increased as salinity rose from 0.1 to 2.3 wt.%. Adding 0.1 g L−1 of Zn-rich g-C3N4 resulted in the removal of 2,4-DCP, 2-chlorohydroquinone, chloroacetophenone, and 2-chloropropionic acid by 99.3%, 99.8%, 98.2%, and 99.9%, respectively, from a real saline wastewater sample with 2.2 wt.% salinity, corresponding to a 67.7% removal of TOC. The EPR results indicated that Zn-rich g-C3N4 generated more free radicals compared to pure g-C3N4, such as·OH and Cl, to degrade organic contaminants. The degradation pathway revealed that 2,4-DCP was first dechlorinated into p-phenol and catechol, which were subsequently degraded into maleic acid/fumaric acid, trihydroxyethylene, acetic acid, oxalic acid, and other products. Furthermore, Zn-rich g-C3N4 demonstrated excellent stability and holds promising potential for applications in saline wastewater treatment.

Improving the accuracy of an integrated watershed-reservoir water quality modeling approach (SWAT and CE-QUAL-W2) in data scarce watersheds

Watershed-reservoir modeling is an essential tool in lake and reservoir management. Despite its importance, accurately modeling these systems remains challenging due to their inherent complexity and the scarcity of reliable forcing data. This study focuses on a watershed and reservoir located in northern Portugal, where data scarcity presents significant challenges for accurate modeling. Therefore, the primary goal of this study was to improve the prediction capability of an integrated watershed-reservoir water quality modeling solution and to establish a robust methodology that can be effectively applied to other cases. The modelling solution proposed in this study computes a daily ratio (per water quality variable) between the watershed reference and load reduction modeling scenarios, obtained with the SWAT model, which is then applied to the observed forcing water quality data of a reservoir water quality model (CE-QUAL-W2). The load reduction scenario increases the watershed municipal wastewater treatment plant’s efficiency from secondary to tertiary and applies a haul-off scenario to the livestock manure, reducing the reservoir input load of Total P, Total N, and BOD5 in the reservoir by 87%,86%, and 83%, respectively. The results obtained with the classical model solution provided an inaccurate conclusion regarding the load reduction scenario output that was corrected with the proposed modeling approach. Overall, after the correction, the load reduction scenario served to considerably improve the reservoir water quality by reducing the Total P and the phytoplankton biomass by 39% and 72%, respectively, while increasing the DO concentration by 27%. The results of this study show that the proposed modeling approach improves the performance of integrated watershed-reservoir modeling systems in data scarce settings and can serve as a useful tool to support decision-making with regard to water resource management and planning at regional and national level.

Risk factors for diarrheal diseases among pilgrims during Arba’een mass gathering: a case-control study

BackgroundA significant portion of the Muslim community participates in the Arba’een pilgrimage, with participant numbers increasing each year. There have been relatively few studies on the health of Arba’een Mass gathering (MG). Researching the prevalence and distribution of diseases among Arba’een pilgrims is essential to recognize any outbreaks and take timely responses to contain them. The current study aimed to identify exposures and risk factors for diarrheal disease in pilgrims who referred to the clinics located in Iraq among the Arba’een MG in 2023.MethodsThis case-control study randomly selected 200 outpatients (100 cases and 100 controls) who were referred to Iraq clinics. Cases were patients with gastrointestinal symptoms (diarrhea), while controls were randomly selected from unaffected pilgrims at the same time for the cases. The study groups matched for age, and sex. Face-to-face interviews using a reliable field based checklist of the Center for Disease Control and Prevention of Iran’s Ministry of Health to collect potential exposures and risk factors for diarrheal disease. Multiple logistic regression was used to estimate the crude and adjusted odds ratio (AOR) for the risk of diarrhea with a 95% confidence interval (CI).ResultsThe average age of the participants was 38.6 years. Diarrhea in 100% and fever in 81% were the most common clinical symptoms in patients. Having underlying diseases was not associated with an increased risk of diarrhea disease (P > 0.05). Regarding risk factors for diarrheal, the final analysis after adjusting for potential confounders indicated that consumption of insanitary (unpackaged) drinking water (AOR = 1.95; 95% CI: 1.05–3.6; P = 0.024), inappropriate hand washing (AOR = 3.82; 95% CI: 1.7–8.6; P = 0.001), ritual foods (AOR = 2.56; 95% CI: 1.3–5.2; P = 0.004), and public toilets (AOR = 1.46; 95% CI: 1.04–4.3; P = 0.038) were significantly increased the likelihood of diarrheal disease.ConclusionsContamination of water sources, food, inadequate and poor hand washing were the most common sources of diarrheal diseases among Arba’een pilgrims. The results indicate that the potential occurrence of outbreaks, especially water- and foodborne diseases, threatens participants in the Arba’een MG. It is recommended to provide risk assessment, improve pilgrims’ awareness, pre-and post-screening, vaccination, compliance with personal hygiene, improvement of the environment, provision of sanitary water and food sources and hygienic disposal of sewage, laboratory diagnosis to identify the common types of pathogens in Arba’een MG.

STRUCTURE OF THE AUTOMATED CONTROL SYSTEM OF TECHNOLOGICAL PARAMETERS OF TREATMENT FACILITIES OF THE CITY SEMEY

Increasing the efficiency of control of treatment facilities can be achieved by automation of control at the stages of observation, collection, processing and analysis of information by means of mathematical data analysis packages, implementation of automated control systems of technological processes.This article is devoted to the issues of technical modernization of automatic control system of water disposal in Semey city. The need to modernize the concept of building the ACS has arisen in connection with the technical re-equipment of production and introduction of new energy-saving technologies in it.The hypothesis of the research suggests the possibility of improving the efficiency of wastewater treatment facilities of Semey city through the use of modern methods of collection and transmission of technological parameters to the control panel of the dispatcher in order to make operational decisions on the management of technological and technological process of wastewater treatment based on monitoring of equipment operation. Due to the complexity of the whole complex of treatment facilities, the main sewage pumping station (GKNS-2) and air blower pumping station (ABPS) were selected as objects for the development of automated control system of technological parameters (ACS TP).The article considers the proposed structural scheme of the automated system of control of technological parameters of treatment facilities of Semey city, gives a description of each level of the system and the principle of their interaction.

Strain-level multidrug-resistant pathogenic bacteria in urban wastewater treatment plants: Transmission, source tracking and evolution

Wastewater treatment plants (WWTPs) serve as reservoirs for various pathogens and play a pivotal role in safeguarding environmental safety and public health by mitigating pathogen release. Pathogenic bacteria, known for their potential to cause fatal infections, present a significant and emerging threat to global health and remain poorly understood regarding their origins and transmission in the environment. Using metagenomic approaches, we identified a total of 299 pathogens from three full-scale WWTPs. We comprehensively elucidated the occurrence, dissemination, and source tracking of the pathogens across the WWTPs, addressing deficiencies in traditional detection strategies. While indicator pathogens in current wastewater treatment systems such as Escherichia coli are effectively removed, specific drug-resistant pathogens, including Pseudomonas aeruginosa, Pseudomonas putida, and Aeromonas caviae, persist throughout the treatment process, challenging complete eradication efforts. The anoxic section plays a predominant role in controlling abundance but significantly contributes to downstream pathogen diversity. Additionally, evolution throughout the treatment process enhances pathogen diversity, except for upstream transmission, such as A. caviae str. WP8-S18-ESBL-04 and P. aeruginosa PAO1. Our findings highlight the necessity of expanding current biomonitoring indicators for wastewater treatment to optimize treatment strategies and mitigate the potential health risks posed by emerging pathogens. By addressing these research priorities, we can effectively mitigate risks and safeguard environmental safety and public health.

Singular Spectrum Analysis of Pathogenic Microorganisms in a Sanitary Wastewater Treatment System

Singular Spectrum Analysis of Pathogenic Microorganisms in a Sanitary Wastewater Treatment System

Enhancing nitrogen removal by simultaneous nitritation and denitritation in a multi-cycle SBR with supplementation of solid carbon sources

Simultaneous nitritation and denitritation have the potential to significantly improve nitrogen removal in sewage treatment processes. However, their application in low-strength sewage treatment systems presents challenges. This study explored the impact of four solid carbon sources (SCSs) on N-removal via nitrite in a multi-cycle SBR with biocarriers. Results showed that both N-removal efficiencies and nitrite accumulation rates increased with higher COD/N ratios, indicating that high COD/N ratios can improve the competition between denitrifiers and nitrite-oxidizing bacteria for nitrite, leading to stable simultaneous nitritation and denitritation. The supplementation of SCSs further enhanced this high-efficiency N-removal process, with polybutylene succinate (PBS) and polycaprolactone (PCL) showing greater increases in N-removal via nitrite than poly-hydroxybutyrate (PHB) and poly-hydroxyalkanoate (PHA). Moreover, PBS showed the most significant increase in denitrification efficiency in anoxic conditions, while PHA was the most effective external SCS at a moderate level of dissolved oxygen. These findings suggest that the incorporation of external SCSs can facilitate the simultaneous nitritation and denitrification process in multi-cycle SBRs, underscoring the importance of selecting an appropriate SCS for optimizing nitrogen removal in sewage treatment projects.

Mechanistic Insights into Toxicity of Titanium Dioxide Nanoparticles at the Micro- and Macro-levels.

Titanium oxide nanoparticles (TiO2 NPs) have been regarded as a legacy nanomaterial due to their widespread usage across multiple fields. The TiO2 NPs have been and are still extensively used as a food and cosmetic additive and in wastewater and sewage treatment, paints, and industrial catalysis as ultrafine TiO2. Recent developments in nanotechnology have catapulted it into a potent antibacterial and anticancer agent due to its excellent photocatalytic potential that generates substantial amounts of highly reactive oxygen radicals. The method of production, surface modifications, and especially size impact its toxicity in biological systems. The anatase form of TiO2 (<30 nm) has been found to exert better and more potent cytotoxicity in bacteria as well as cancer cells than other forms. However, owing to the very small size, anatase particles are able to penetrate deep tissue easily; hence, they have also been implicated in inflammatory reactions and even as a potent oncogenic substance. Additionally, TiO2 NPs have been investigated to assess their toxicity to large-scale ecosystems owing to their excellent reactive oxygen species (ROS)-generating potential compounded with widespread usage over decades. This review discusses in detail the mechanisms by which TiO2 NPs induce toxic effects on microorganisms, including bacteria and fungi, as well as in cancer cells. It also attempts to shed light on how and why it is so prevalent in our lives and by what mechanisms it could potentially affect the environment on a larger scale.

When cellulose nanocrystals meet graphene oxide: Structurally enhanced aerogels for efficient solar steam generation and water purification

Pollution, population growth, and climate change are intensifying global freshwater shortages. Traditional methods of collecting freshwater, such as rainwater harvesting and sewage treatment, have high energy consumption, limiting their implementation in underdeveloped regions. On the other hand, solar-driven seawater evaporation offers a promising solution, purifying water using naturally abundant solar energy. Reduced graphene oxide (rGO) is considered as a strong candidate for this purpose due to its broad spectral absorption. However, its hydrophobicity hinders its direct use in solar steam generators. Here, we report the preparation of a series of cellulose nanocrystal (CNC)-rGO aerogels (CGAs) through a one-pot hydrothermal gelation process, followed by unidirectional freeze-drying. The introduction of CNCs enhances the hydrophilicity and structural stability of the resulting CGAs. The CGAs also feature uniform and unidirectional channels that promote efficient water transport, as confirmed by scanning electron microscopy (SEM) and X-ray microtomography (XMT). The CGAs have an optimized water evaporation rate of 1.80 kg m−2 h−1 under 1 sun irradiation, with 90 % solar-to-vapor energy efficiency. Moreover, durability and seawater desalination tests provide additional evidence for the practicality of CGAs in water purification. It is anticipated the implementation of CGAs will expedite the application of solar steam generators in practical scenarios.

Tracing contaminants of emerging concern and their transformations in the whole treatment process of a municipal wastewater treatment plant using nontarget screening and molecular networking strategies

This study employed nontarget screening with high-resolution mass spectrometry and molecular network strategy to characterize the occurrence and tranformation of contaminants of emerging concern (CECs) through a wastewater treatment plant in Guangzhou. We detected 70,631 compounds in positive mode and 14,423 in negative mode in influent, from which 94.5 % of these compounds were successfully eliminated after treatment. Among them, 510 chemicals were identified, with pharmaceuticals being the largest category excluding natural products, accounting for 146 compounds. And 29 CECs were semiquantified with concentrations ranging from 2.80 ng/L (Fluconazole) to 10,351 ng/L (Nicotine). The removal efficiency varied: 60 compounds were easily removable (>90 % removal), 17 were partially removable (40–90 % removal), and 44 were non-degradable (<40 % removal). Additionally, we tentatively identified transformation products (TPs) of CECs using a molecular network analysis, revealing over 20,000 compound pairs sharing common fragments, with 191 compounds potentially linked to 47 level 1 compounds, suggesting their role as TPs of CECs. These findings illuminated the actual treatment efficiency of wastewater treatment plants for CECs and the potential TPs, offering valuable insights for future improvements in wastewater management practices.

Evaluation of activated carbon fiber packed-bed for the treatment of gas-to-liquid wastewater: experimental, modeling and ASPEN Adsorption simulation

AbstractThis study investigates the continuous adsorption treatment of gas-to-liquid (GTL) wastewater from the Fischer-Tropsch process using activated carbon fiber (ACF) as the adsorbent. ACF, characterized by a high surface area of 1232 m²/g, was utilized to treat actual GTL wastewater, which contains long and short-chain alcohols, fatty acids, and other hydrocarbons. Experimental analysis, packed-bed modeling and simulation using ASPEN Adsorption were employed to understand the dynamics of the adsorption process. The experimental setup involved a bench-scale column packed with specified masses of ACF, with GTL wastewater pumped upward through the column at varying flow rates. Breakthrough curves were constructed to assess column performance, with parameters, such as feed flow rate (5 and 10 mL/min) and packing mass (5 and 10 g) systematically varied. The results demonstrate a significant influence of these parameters on column performance, with higher flow rates initially accelerating adsorption kinetics. Conversely, increasing packing mass extends the duration of column saturation, improving efficiency. Empirical models, including the Yoon-Nelson and El-Naas et al. models were applied to fit the experimental data, with the latter showing superior performance in representing the adsorption mechanism within the column. Quantitative analysis of model fitting using Akaike Information Criteria (AIC) identified the Yoon-Nelson and El-Naas et al. model as the most suitable for describing the GTL wastewater/ACF system, with an AIC weight parameter of 0.33 and R2 averaging 86.5%. Furthermore, simulation results from ASPEN Adsorption exhibited strong agreement with experimental data, validating its efficacy for simulating liquid adsorption processes. The study provides valuable insights into the design and optimization of large-scale wastewater treatment systems, offering practical solutions to address global water challenges.

Hydrothermal synthesis of nanostructured Zn2SnO4 ternary metal oxide semiconductor for toxic gas sensing application and its characterization study

Purpose The study aims to develop an inexpensive metal oxide semiconductor gas sensor with high sensitivity, excellent selectivity for a specific gas and rapid response time. Design/methodology/approach This study synthesized Zn2SnO4 nanostructures using a hydrothermal method with a 1 M concentration of zinc chloride (ZnCl2) as the zinc source and a 0.7 M concentration of tin chloride (SnCl4) as the tin source. Thick films of nanostructured Zn2SnO4 were then produced using screen printing. The structural properties of Zn2SnO4 were confirmed using X-ray diffraction, and the formation of Zn2SnO4 nanoparticles was verified by transmission electron microscopy. Scanning electron microscopy was used to analyse the surface morphology of the fabricated material, while energy dispersive spectroscopy provided insight into the chemical composition of the thick film. These fabricated thick films underwent testing for various hazardous gases, including nitrogen dioxide, ammonia, hydrogen sulphide (H2S), ethanol and methanol. Findings The nanostructured Zn2SnO4 thick film sensor demonstrates a notable sensitivity to H2S gas at a concentration of 500 ppm when operated at 160°C. Its selectivity, response time and recovery time were assessed and documented. Research limitations/implications The primary limitations of this research on metal oxide semiconductor gas sensors include poor selectivity to specific gases, limited durability and challenges in achieving detection at room temperature. Practical implications The nanostructured Zn2SnO4 thick film sensor demonstrates a strong response to H2S gas, making it a promising candidate for commercial production. The detection of H2S is crucial in various sectors, including industries and sewage plants, where monitoring this gas is essential. Social implications Currently, heightened global apprehension about atmospheric pollution stems from the existence of perilous toxic and flammable gases. This underscores the imperative need for monitoring such gases. Toxic and flammable gases are frequently encountered in both residential and industrial environments, posing substantial hazards to human health. Noteworthy accidents involving flammable gases have occurred in recent years. It is crucial to comprehend the presence and composition of these gases in the surroundings for precise detection, measurement and control. Thus, there has been a significant push for extensive research and development in diverse sensor technologies using various materials and methodologies to monitor and regulate these gases effectively. Originality/value In this research, Zn2SnO4 nanostructures were synthesized using a hydrothermal method with ZnCl2 at a concentration of 1 M for zinc and SnCl4 at a concentration of 0.7 M for tin. Thick films of nanostructured Zn2SnO4 were then fabricated via screen printing technique. Following fabrication, all thick films were subjected to testing with various toxic gases, and the results were compared to previously published data. The analysis indicated that the nanostructured Zn2SnO4 thick film sensor demonstrated outstanding performance concerning gas response, gas concentration, selectivity and response time, particularly towards H2S gas.

The ability of UWWTP to remove NSAIDs: Impact on water quality in the Odra River Czech Republic concerning incoming European legislation

Increased consumption of pharmaceuticals has resulted in their detection in wastewater. If wastewater treatment plants (WWTPs) fail to eliminate these substances adequately, they can seep into the environment, posing potential risks. As non-steroidal anti-inflammatory drugs (NSAIDs) belong to the pharmaceuticals most frequently examined in wastewater, this study aimed to monitor wastewater from the municipal wastewater treatment plant in Ostrava (UWWTP) over the course of a year, specifically assessing how the presence of these substances in discharged wastewater could contaminate the Odra River. To further understand the impact of NSAIDs, we evaluated the effectiveness of UWWTP technology in removing the following selected drugs: diclofenac (DCF), ibuprofen (IBU), naproxen (NAP) and ketoprofen (KET) - as well as their main metabolites: 4′-hydroxydiclofenac (hydroxyDCF), carboxyibuprofen (carboxyIBU), desmethylnaproxen (desmethylNAP), and ketoprofen glucuronide (glucuronideKET).Wastewater samples were collected at both the inflow and outflow of the urban wastewater treatment plant (UWWTP) Ostrava from October 2022 to September 2023. The analysis was performed using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). The concentrations of the monitored substances at the UWWTP inflow varied significantly, ranging from 79 ng/L to 112,125 ng/L, with the highest levels detected for ibuprofen (IBU), diclofenac (DCF), and their metabolites. The UWWTP demonstrated impressive treatment efficiency for IBU, exceeding 98%, while for DCF, it ranged between 56% and 87%. Building on these findings, a monitoring campaign was initiated along the Odra River to evaluate the concentrations of IBU and DCF - substances that had not been measured before. Water samples were taken from various locations along the Odra River from October to November 2023 and analyzed using the same methodology as the wastewater samples. The results indicate that, in line with the proposed environmental quality standards (EQS), IBU and DCF do not pose a significant contamination risk to the Odra River.

Application of sewage sludge derived hydrochar as an adsorbent for removal of methylene blue

Hydrothermal pretreatment (HTP) is used to convert biomass into hydrochar (HC) through the application of heat and pressure in a water-based medium. The HC has emerged as a promising material for various environmental applications including wastewater treatment, soil amendment, and carbon sequestration. In this study, the applicability of sewage sludge (SS) derived HC was tested as an adsorbent for methylene blue (MB) dye removal from wastewater. The HC was also subjected to chemical activation with KOH before the adsorption study. The HC samples were characterized for structural morphology and molecular functionalities using instrumental analysis. All the HC samples exhibited almost similar adsorption capacity (∼190 mg/g) for MB after 24 h of contact time (MB concentration = 200 mg/L, solution pH = 7 and adsorbent dose = 1 g/L). The equilibrium data could be adequately fit in Langmuir model equation. The negative value of free energy indicated favorable MB adsorption process. The study demonstrated that the SS derived HC can be recycled as adsorbent in wastewater treatment plant which is not only an environment-friendly approach but also may reduce cost of tertiary treatment at sewage treatment plant often required to remove emerging contaminants.

Spatial conversion characteristics of sulfur and nitrogen via desulfurization denitrification under rapidly changing hydraulic conditions

The sulfur-nitrogen-contained wastewater treatment system needs fast start-up, efficient collaboration, and stability, to break through the application bottleneck of biological desulfurization-denitrification. An integrated sleeve bioreactor was adopted to analyze the coupling performances of sulfate-reduction and sulfide-based denitrification process. The spatial-temporal distribution of functional bacteria and genes was studied under rapidly changing hydraulic conditions. The transformation law of carbon-sulfur-nitrogen was clarified. The removal efficiencies of sulfate, total organic carbon, and nitrite reached 90 %, 98 %, and 99 %, respectively. Thermovirga, Desulfomicrobium and Desulfobulbus were the main functional bacteria in the external sleeve, while Sulfurovum and sulfurimonas were in the internal sleeve. The dominant functional genes sat, sqr, norBC, and nosZ had relative abundances of 1.02 ‰, 3.09 ‰, 0.63 ‰ and 0.51 ‰, respectively. The sleeve alleviated the toxic effects of sulfide and nitrite. It realized the spatial separation and enrichment of different dominant bacteria, improving the load shock resistance of bioreactor. The rapidly changing hydraulic retention time promoted the spatial transference of sulfate-reducing bacteria and brought the appearance of sulfide-based denitrification bacteria in external sleeve. It enhanced the stability of microbial community structure. This optimized microbial community structure provided a rich diversity of functional genes to ensure a collaborating degradation of sulfur and nitrogen. The main transformation pathways included the assimilated sulfate reduction, sulfur partial oxidation and denitrification. Rapidly decreasing hydraulic retention time facilitated the accumulation of elemental sulfur. The unique structure and operation exhibited strong resistance to loads and hydraulic shocks. This work provides a reference value for efficiently removing multiple pollutants in sulfur-nitrogen-polluted wastewater.

Effect of the residual levofloxacin on hydroponic vegetables with sewage treatment plant tailwater: Microbial community, discharge risk and control strategy

Tailwater-based hydroponic vegetable is a promising strategy for domestic wastewater recycling. However, the effect of residual antibiotics on the hydroponic vegetable system and the relation between hydroponic culture parameters and the residual water quality are still unclear. Here, the typical antibiotic Levofloxacin (LVFX) was employed, and the effect of LVFX (5 mg/L) on the residual water quality, plant growth and microbial community of water spinach hydroponic culture system were investigated under different hydraulic residence times (HRT). Obvious toxic effects on water spinach were observed, and the highest removal rate of LVFX (about 6 %) and TN (25.67±1.43 %) was observed when HRT was 7 days. Hydroponic culture increased the microbial abundance, diversity, and microbial community stability. To optimize the hydroponic culture, actual sewage plant tailwater spiked with 20 μg/L LVFX, along with three common planting substrates (sponge, ceramsite, and activated carbon) were used for the hydroponic culture of lettuce (seasonal reasons). The inhibition effect of LVFX on the removal of NO3--N and TN was observed even as the LVFX concentration decreased significantly (from 14.62 ± 0.44 μg/L to 0.65 ± 0.07 μg/L). The best growth situation of lettuce and removal rates of NH4+-N, NO3--N, TN, especially LVFX (up to 95.65 ± 0.54 %) were observed in the activated carbon treated group. The overall results indicate the negative effect of residual antibiotics on the hydroponic vegetable systems, and adding activated carbon as substrate is an effective strategy for supporting plant growth and controlling discharged risk.

An indigenous microalgal pool containing Klebsormidium sp. K39 as a stable and efficacious biotechnological strategy for Escherichia coli removal in urban wastewater treatment

AbstractBACKGROUNDIn recent decades the demand for freshwater has drastically increased as a consequence of population growth, economic development, climate change and pollution. Therefore, any strategy for wastewater treatment can play a role in alleviating the pressure on freshwater sources.RESULTSIn the present study an autochthonous microalgal pool (MP), isolated from a constructed wetland, was proposed as an alternative to the secondary treatment of an urban wastewater treatment system. The MP removal efficacy was compared to those obtained using Chlorella vulgaris and Scenedesmus quadricauda, against E. coli. Results exhibited a comparable removal efficacy and after 2 days, in samples inoculated with E. coli at lower density, S. quadricauda and C. vulgaris induced a decrease of 2.0 units Log and the autochthonous MP of 1.8 units Log, whereas in samples with E. coli at higher density the bacteria were reduced 2.8, 3.4 and 2.0 units Log by S. quadricauda, C. vulgaris and the autochthonous MP, respectively. Moreover, the identification of microalgal strains isolated from the MP revealed the presence of Klebsormidium sp. K39, C. vulgaris, Tetradesmus obliquus and S. quadricauda. Although the MP composition remained quite constant, at the end of the treatment, a different distribution among the microalgal species was observed with Klebsormidium sp. K39 found as dominant.CONCLUSIONThe microalgal‐based wastewater treatment appears as a valuable alternative, although further investigations, based on ‘omics’ approaches, could be applied to better explore any fluctuation within the MP species composition in an in situ trial. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley &amp; Sons Ltd on behalf of Society of Chemical Industry.

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.