Organic Compounds In Wastewater Research Articles

The Elimination of Levofloxacin from High-Salinity Wastewater via the Electrochlorination Process

The electrochlorination (E-Cl) process has attracted much attention as it is a highly efficient method for treating organic compounds in hypersaline wastewater. In this study, the E-Cl process was utilized for the removal of antibiotics. The optimal experimental conditions were determined to be a NaCl concentration of 100 mM, a current density of 1.5 mA/cm2, a pH of 7.0, and a plate spacing of 1 cm, with a levofloxacin (LEV) degradation efficiency reaching as high as 99% using this setup. The effects of the presence of other ions and humic acid on the E-Cl process were investigated, and it was found that the degradation of LEV was not significantly affected by the presence of coexisting substances. In addition, free chlorine was identified as the primary active species for the degradation of LEV by means of a quenching experiment. It was demonstrated by 3D EEM and TOC that LEV was not completely mineralized and that intermediate products may be present. In order to reveal the degradation pathways of LEV, its degradation products were also analyzed via LC-MS, and some possible pathways of LEV degradation in this system were proposed. The successful degradation of LEV demonstrated that the E-Cl process is an efficient and promising technique for the treatment of organic pollutants in high-salinity wastewater.

A Comprehensive Approach to Azo Dichlorotriazine Dye Treatment: Assessing the Impact of Physical, Chemical, and Biological Treatment Methods through Statistical Analysis of Experimental Data

This exploration investigates integrated treatment systems combining advanced oxidation processes (Fenton and photo-Fenton) with biological methods for the effective elimination of stubborn organic compounds in simulated textile wastewater composed of azo Dichlorotriazine dye. A comprehensive optimization of key process factors including catalyst dosage, hydrogen peroxide quantity, irradiation duration, etc. was systematically conducted for both Fenton and photo-Fenton processes to realize maximum COD and color removal. Under ideal conditions (0.4 g/L photocatalyst, 1 mL/L H2O2, and 75-Watt UV intensity for 60 min), the photo-Fenton process realized 80% COD elimination and complete decolorization, meeting industrial discharge limits without needing extra biological treatment. Statistical models correlating process parameters to treatment efficiency were developed, giving important design insights. For Fenton, effluent COD exceeded discharge thresholds, so a post-biological treatment using activated sludge was essential to comply with regulations. This integrated Fenton–biological scheme utilizes synergism between chemical and biological processes for enhanced overall treatment. Notable economic benefits were achieved by photo-Fenton over conventional UV-only and UV/H2O2 methods regarding energy consumption and operating costs. Overall, this pioneering work successfully proves integrated advanced oxidation–biological systems as a superior, sustainable alternative to traditional techniques for economically removing obstinate pollutants, such as azo Dichlorotriazine dye, as it is a simulated textile wastewater treatment used to satisfy environmental standards.

Investigation on pulsed-electrocoagulation process for the treatment of wet coffee processing wastewater using an aluminum electrode

The use of conventional direct current-electrocoagulation in wastewater treatment is limited by its drawbacks, which include electrode passivation, high energy consumption, and significant sludge generation. Therefore, to address these issues, pulsed-electrocoagulation (PECP) has been developed. The PECP is an advanced wastewater treatment technique that uses intermittent electrical pulses to target and break down organic compounds in wastewater. It offers several benefits, including enhanced removal of organic compounds, reduced chemical consumption, energy efficiency, treatment of complex wastewater composition, pathogen inactivation, environmental compliance, and potential for water reuse. In this research, removal efficiency of % Chemical Oxygen Demand (COD), % Color, % Turbidity, % phosphate, and %nitrate was investigated for the wet coffee processing wastewater by using PECP and the obtained results as the COD-98.75%, color-99.92%, turbidity-99.00%, phosphate-99.02%, and nitrate-98.83%, respectively. Independent variables were the major significant factors and the optimum value was investigated and obtained at pH of 7, electrolyte dosage of 0.75 g L−1, electrolysis time of 45 min, and current of 0.45 Amp. As a result, PECP with NaCl and CaCl2 as an electrolyte is an effective treatment technique for pollutant removal from wastewater. As a consequence, the specific benefits may vary depending on the system design, operational parameters, and wastewater characteristics. The pilot-scale studies and optimization are essential for assessing PECP feasibility and performance.

The Aerobic Granules Process for Wastewater Treatment: From Theory to Engineering

Aerobic granules are small, dense aggregates of microbial cells that form naturally in aerobic wastewater treatment systems. They are characterized by their spherical shape, strong structural integrity, and ability to rapidly settle. These granules are formed through a self-immobilization process where different microbial species coalesce to degrade organic and inorganic compounds in wastewater. This study summarizes the development of aerobic granulation technology in wastewater treatment and the mechanism of aerobic granules’ formation, analyzes the characteristics and the factors affecting the aerobic granules’ formation, and presents practical engineering examples of its application from pilot-scale to full-scale operation.

Cathodic membrane with confined interlayer spacing for efficient electrocatalytic dehalogenation of antibiotics

Conventional catalytic membranes often exhibit inadequate catalytic efficiency due to limited retention time for pollutants during filtration. In this study, a single-atom catalyst (Ni-NG) was prepared by dispersing single nickel atoms onto nitrogen-doped graphene oxide sheets. Subsequently, under controlled conditions, the assembly of Ni-NG with reduced graphene oxide (rGO) sheets led to the fabrication of efficient electrocatalytic cathodic membranes (ECMs). The ECMs were designed to concentrate and dehalogenate antibiotics simultaneously by utilizing the confined single nickel atoms within the multilayered ECMs through electrocatalytic reduction. Remarkably, complete degradation of chloramphenicol (CAP, 20 mg L−1) in the solution was achieved within a remarkably short time of 3.0 ms by ECM8 which had an area of 7.1 cm2 and comprised Ni-NG (16.9 μg) and rGO (16.9 μg), with an interlayer spacing of 0.37 nm, during filtration (40 L m−2 h−1). The reaction rate constant (k) for CAP degradation by ECM8 was approximately 3 × 108 min−1, surpassing the highest value in the literature. Furthermore, the ECM demonstrated both high energy efficiency and stability, highlighting the great potential for practical applications. The electrocatalytic cathodic membrane, designed to primarily concentrate pollutants in confined interlayer spaces through the sieving effect, shed lights on the highly efficient dehalogenation of organic compounds in pharmaceutical salt-laden wastewater.

Photocatalytic degradation of organic compounds in dye wastewater by Fe3+ doped nano-ZnO/TiO2 composite photocatalyst

Photocatalytic degradation of organic compounds in dye wastewater by Fe3+ doped nano-ZnO/TiO2 composite photocatalyst

Economic evaluation for anoxic biological system integrated with external membrane for pharmaceutical wastewater treatment

The integrated system of biological treatment (anoxic /activated sludge ) and ultrafiltration membrane economic study was investigated. The biological treatment results indicate that the performance of pharmaceutical industrial wastewater treatment using activated sludge with an anoxic zone was enhanced by increasing the ability of the pre-acclimatized activated sludge to degrade organic compounds in the industrial wastewater. The residues compounds from biologically treated water were treated by UF membrane and gave a separation efficiency of 99.4%. The results indicate that using the (anoxic /activated sludge) biological treatment step as a pretreatment step before the membrane can provide high-efficiency removal of the contamination of all drug compounds in the wastewater. An economic evaluation of the system was investigated and the calculations indicate that the unit capital cost of the estimated system per cubic meter was 1.27 $/m3, which was lower than the estimated traditional cost.

N-methyl pyrrolidone manufacturing wastewater as the electron donor for denitrification: From bench to pilot scale

Actual wastewater generated from N-methylpyrrolidone (NMP) manufacture was used as electron donor for tertiary denitrification. The organic components of NMP wastewater were mainly NMP and monomethylamine (CH3NH2), and their biodegradation released ammonium that was nitrified to nitrate that also had to be denitrified. Bench-scale experiments documented that alternating denitrification and nitrification realized effective total‑nitrogen removal. Ammonium released from NMP was nitrified in the aerobic reactor and then denitrified when actual NMP wastewater was used as the electron donor for endogenous and exogenous nitrate. Whereas TN and NMP removals occurred in the denitrification step, dissolved organic carbon (DOC) and CH3NH2 removals occurred in the denitrification and nitrification stages. The genera Thauera and Paracoccus were important for NMP biodegradation and denitrification in the denitrification reactor; in the nitrification stage, Amaricoccus and Sphingobium played key roles for biodegrading intermediates of NMP, while Nitrospira was responsible for NH4+ oxidation to NO3−. Pilot-scale demonstration was achieved in a two-stage vertical baffled bioreactor (VBBR) in which total‑nitrogen removal was realized sequential anoxic-oxic treatment without biomass recycle. Although the bench-scale reactors and the VBBR had different configurations, both effectively removed total nitrogen through the same mechanisms. Thus, an N-containing organic compound in an industrial wastewater could be used to drive total-N removal in a tertiary-treatment scenario.

Characteristics and potential cytotoxicity of halogenated organic compounds in shale gas wastewater-impacted surface waters in Chongqing area， China

Recent screening surveys have shown the presence of unknown source halogenated organic compounds (HOCs) in shale gas wastewater. However, their occurrence, profile, transport in surrounding surface water and environmental risk potentials remain unclear. Here, a method for the extraction and quantitative determination of 13 HOCs in water by solid phase extraction combined with gas chromatography–mass spectrometry (GC–MS) was established. All of the targeted HOCs were detected and peaked at the outfall, while these contaminants were generally not detected in samples upstream of the outfall, suggesting that these contaminants originated from the discharge of shale gas wastewater; this was further supported by the fact that these pollutants were generally detected in downstream samples, with a tendency for pollutant concentrations to decrease progressively with increasing distance from the outfall. However，different HOCs had different transport potential in water. In addition, the toxicological effects of typical HOCs were evaluated using HepG2 as a model cell. The results indicated that diiodoalkanes suppressed HepG2 cell proliferation and induced ROS generation in a concentration-dependent manner. Mechanistic studies showed that diiodoalkanes induced apoptosis in HepG2 cells via the ROS-mediated mitochondrial pathway, decreasing mitochondrial membrane potential and increasing intercellular ATP and Ca2+ levels. On the other hand, RT–qPCR and Western blot assays revealed that the SLC7A11/GPX4 signaling pathway and HO-1 regulation of ferritin autophagy-dependent degradation (HO-1/FTL) pathway were involved in the ferroptosis pathway induced by diiodoalkane in HepG2 cells. Our study not only elucidates the contamination profiles and transport of HOCs in surface water of typical shale gas extraction areas in China, but also reveals the toxicity mechanism of typical diiodoalkane.

Removal of organic compounds in wastewater using cocoa shell‑based activated carbon–SiO2 nanoparticles

AbstractThis work aimed to use low-cost residual cocoa shell biomass for the preparation of activated carbon with different amounts of SiO2 nanoparticles using the coprecipitation method. The use of residual plant biomass seeks to strengthen the challenges of the bioeconomy in the generation of value-added products for the agro-industry. Subsequently, the adsorption capacity of phenol and 3,4-dimethoxybenzyl alcohol as representative species of persistent organic pollutants was quantified. The chemical activation of the carbon was carried out at 480 °C during 30 min with a 1.5 phosphoric acid (H3PO4) impregnation ratio. The activated carbons were characterized by Fourier transform infrared spectroscopy (FTIR), showing the presence of functional groups associated with substances such as phenols, carboxylic acids, aromatic rings, and SiO2. Also, activated carbons were structurally characterized with scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS), finding that the granules had structured surfaces but with irregular size and disordered channels, which facilitates the impregnation of SiO2 nanoparticles onto the activated carbon surface. The adsorption study of the organic compounds was carried out using UV–Vis spectroscopy. The adsorption isotherms, which were adjusted to the Langmuir, Freundlich and Temkin models, were determined with correlation coefficients of 0.9835, 0.9885 and 0.987. On the other hand, the adsorbent materials achieved removal percentages around 97.9% and 97.8% for phenol and 3,4-dimethoxybenzyl alcohol, respectively. The results showed that activated carbons with SiO2 nanoparticles increased the specific surface area by up to 20%. Therefore, this property allows a greater interaction of contaminants at the time of adsorption. Graphical abstract

Electrocatalytic Degradation of Rhodamine B on the Sb-Doped SnO2/Ti Electrode in Alkaline Medium.

To realize efficient electrocatalytic degradation of organic compounds in alkaline wastewater, an Sb-doped SnO2/Ti electrode was fabricated and employed for the removal of Rhodamine B (RhB), and the electrocatalytic oxidation performance of this electrode was assessed in an alkaline medium. In an alkaline solution (pH 11), the complete fading of 50 mg·L-1 RhB could be achieved after 150 min of degradation, the removal efficiency of the chemical oxygen demand reached 56.1% at 300 min, and the degradation process of RhB followed the pseudo-first-order kinetic model very well. Under the attack of hydroxyl radicals, partial RhB was degraded to low-molecular-weight organic acids through N-demethylation and the destruction of the conjugated chromophore. Various techniques including scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and cycle voltammetry were used to examine the changes in the morphology and structure, as well as the activity of the Sb-doped SnO2/Ti electrode before and after use. The Sb-doped SnO2/Ti electrode could be reproduced in batches, and each electrode was reused up to eight times without a significant decrease in degradation ability; the leaching amount of antimony was significantly lower than the national emission standard. The electrocatalytic oxidation of the dye wastewater sample was also performed with the desired results, indicating that electrochemical oxidation is a very promising technology for the treatment of alkaline dye wastewater using a Sb-doped SnO2/Ti electrode.

Correlations between organic pollution indicators in municipal wastewater

The paper presents the results of a study of parameters used for determining the amount of organic pollutants in wastewater flowing into a collective wastewater treatment plant with a population equivalent of about 120 000 PE. The plant constituted part of a sewage system. Assays were performed for biochemical oxygen demand (BOD5), chemical oxygen demand (CODCr), permanganete index (CODMn) and total organic carbon (TOC). In addition, the pH of wastewater and its alkalinity were determined. Sampling of incoming wastewater and measurement of physicochemical parameters were performed once a week, in the spring. A total of 44 samples of wastewater were collected. The correlations between the individual parameters and the correlations between the ratios of these parameters were determined. It was found that it was possible to estimate, with suffi cient accuracy, the values of selected parameters for determining the concentrations of organic compounds in municipal wastewater, knowing the values of other parameters in this group. Moreover, it was shown that, knowing the relationship between the analyzed parameters, one can find multiple regression equations for a given type of wastewater, which allow one to calculate the remaining relationships with a good fit, i.e. a determination factor R2greater than 0.6

Investigating the applicability of waste foam concrete for phosphorus recovery in real pig wastewater based on the effect of organic matter on the HAP crystallisation method

HAP crystallization use waste foam concrete as a calcium source, studied the impact of typical organic compounds in simulated pig wastewater on phosphorus recovery, and applied them to actual wastewater. Energy dispersive X-ray spectrometer(EDS) and SEM indicate: citric acid had a stronger inhibitory effect on crystallization compared to humic acid. Citric acid chelated Ca2+ ions, competing with crystallization ions and interfering with crystal nucleation. Humic acid hindered crystal growth through adsorption and ion exchange mechanisms. When citric acid and humic acid were added together, they competitively interacted, reducing the inhibition of phosphorus recovery. HAP crystallization alone reduced phosphorus content and turbidity in secondary pig wastewater, while combining 2 mL(5 g/L)PAM yielded favorable outcomes. Effluent phosphorus concentration was only 1.0 mg/L, with turbidity below 25. here was a noticeable reduction in Pseudomonas pathogenic bacteria from the Aspergillus phylum, along with a significant downward trend in the CL500_29_marine_group, which represents water body eutrophication. The combined method cost RMB 1.15 yuan/ton of water treated, a 26 % decrease compared to the original treatment plant. This method is suitable as an add-on unit for secondary pig wastewater treatment.

The synergistic role of ozonation and hydrolysis acidification on the enhanced pre-treatment of high-strength refractory 2-butenal manufacture wastewater: Performance, metabolism, and mechanisms

Targeted removal of three key refractory toxic organic compounds (TOMs) in 2-butenal manufacturing wastewater (2-BMW) is critical for enhancing pre-treatment by hydrolysis acidification (HA). We investigated the pre-treatment of 2-BMW with HA, coupled with ozonation in this study. Our results indicated that the removal rate of these key TOMs and the detoxification rate reached almost 100% and 46.3%, respectively, by ozonation under only 0.099 mg O3/mg chemical oxygen demand (COD). The organic load rate (OLR) reached 10.25 ± 0.43 kg COD/m3·d, and the acidification degree (AD) and detoxification efficiency reached 56.0% and 98.3%, respectively, with enhancements of 35.1% and 55.2%, respectively, compared with HA alone. The removal rate of the three key TOMs was improved by > 75%. The degradation pathways of these key TOMs were ring cleavage and ester formation by ozonation, followed by fermentation and acid production by HA. Ultimately, the synergistic role of ozonation and HA was revealed. The preferential cleavage of these key TOMs by ozonation was achieved because of their high electron cloud density and multiple reaction sites, which generated more fermentation-friendly products. The fermentation and acid production reactions may be directly involved in these products. Functional bacteria and key metabolic pathways were also enhanced by ozonation.

Nontarget Insights into the Fate of Cl-/Br-Containing DOM in Leachate during Membrane Treatment.

Halogenated organic compounds in wastewater are persistent and bioaccumulative contaminants of great concern, but few are known at the molecular level. Herein, we focus on nontarget screening of halogenated dissolved organic matter (DOM) in highly concentrated organic matrices of waste leachates and their concentrates. Solid-phase extraction (SPE) was optimized before capturing halogenated signatures via HaloSeeker 2.0 software on mining full-scan high-resolution mass spectrometry (HRMS) fingerprints. This study identified 438 Cl-/Br-containing DOM formulas in 21 leachates and membrane concentrates. Among them, 334 formulas were achieved via SPE with mixed-sorbent cartridges (mixed-SPE), surpassing the 164 formulas achieved through Bond Elut PPL cartridges (PPL-SPE). Herein, only four samples identified via PPL-SPE exhibited a resolution of >50% for extracted Cl-/Br-containing DOM by either SPE. The halogenated DOM constituted 6.87% of the total DOM mass features. Nevertheless, more abundant adsorbable organic halogens deciphered waste leachates and highly concentrated waste streams as reservoirs for halogenated contaminants. Remarkably, 75.7-98.1% of Cl-/Br-containing DOM in primary membrane concentrates remained stable through the secondary membrane treatment, indicating the persistence of these unknown contaminants even post-treatment.

Adsorption and Degradation of Organics in Wastewater on Municipal Sludge.

Adsorption and degradation of organic compounds on sludge were investigated by comparing activated and inactivated sludge at various dosages, pH values, and temperatures. The organic compounds in wastewater were identified and evaluated through fluorescence spectra. The results show that optimum adsorption occurred as the activated and inactivated sludge concentration was 4000 mg/L at a pH of 7.99 and a temperature of 30 °C. The fluorescence scanning spectrum indicated that activated sludge could remove protein-like organic matter, fulvic acid-like organic matter, and humic acid-like organic matter by 22.1, 9.4, and 41.2%, respectively, via adsorption only or by 25.9, 9.8, and 74.3%, respectively, via adsorption and degradation. Under optimum conditions, by using the good adsorption performance of sludge combined with other sewage treatment technologies, the treatment of high-content organic wastewater can be achieved.

Designing advanced S-scheme CdS QDs/La-Bi2WO6 photocatalysts for efficient degradation of RhB.

Finding effective strategies to design efficient photocatalysts and decompose refractory organic compounds in wastewater is a challenging problem. Herein, by coupling element doping and constructing heterostructures, S-scheme CdS QDs/La-Bi2WO6 (CS/LBWO) photocatalysts are designed and synthesized by a simple hydrothermal method. As a result, the RhB degradation efficiency of the optimized 5% CS/LBWO reached 99% within 70min of illumination with excellent stability and recyclability. CS/LBWO shows improvement in the adsorption range of visible light and promotes electron-hole pair generation/migration/separation, attributing the superior degradation performance. The degradation RhB mechanism is proposed by a free radical capture experiment, electron paramagnetic resonance, and high-performance liquid chromatography-mass spectrometry results, indicating that h+ and •O2 - play a significant role during four degradation processes: de-ethylation, chromophore cleavage, ring opening, and mineralization. Based on in situ irradiated X-ray photoelectron spectroscopy, Mulliken electronegativity theory, and the work function results, the S-scheme heterojunction of CS/LBWO promotes the transfer of photogenerated electron-hole pairs and promotes the generation of reactive radicals. This work not only reports that 5% CS/LBWO is a promising photocatalyst for degradation experiments but also provides an approach to design advanced photocatalysts by coupling element doping and constructing heterostructures.

The Effects of Low-frequency Pulsed Electromagnetic Fields on the Cleaning of Household Wastewater

The effect of pulsed EMF with a pulse repetition frequency of 16 Hz on the decomposition of organic compounds in wastewater in the presence of activated sludge microorganisms has been studied. It is shown that aerobic purification of a mixture of wastewater and activated sludge in the presence of a continuous pulsed electromagnetic field with a frequency of 16 Hz and a magnetic induction of no more than 0.5 μT accelerates the process of ammonification by 25 %, nitrification and denitrification by 15 %, reduction of COD by approximately 20 %.The intensity of the increase in the biomass of activated sludge and the rate of its deposition were noted.

Designing a Graphene Metasurface Organic Material Sensor for Detection of Organic Compounds in Wastewater.

In many fields, such as environmental monitoring, food safety, and medical diagnostics, the identification of organic compounds is essential. It is crucial to create exceptionally sensitive and selective sensors for the detection of organic compounds in order to safeguard the environment and human health. Due to its outstanding electrical, mechanical, and chemical characteristics, the two-dimensional carbon substance graphene has recently attracted much attention for use in sensing applications. The purpose of this research is to create an organic material sensor made from graphene for the detection of organic substances like phenol, ethanol, methanol, chloroform, etc. Due to its high surface-to-volume ratio and potent interactions with organic molecules, graphene improves the sensor's performance while the metasurface structure enables the design of highly sensitive and selective sensing elements. The suggested sensor is highly sensitive and accurate at detecting a broad spectrum of organic molecules, making it appropriate for a number of applications. The creation of this sensor has the potential to have a substantial impact on the field of organic sensing and increase the safety of food, medicine, and the environment. The graphene metasurface organic material sensor (GMOMS) was categorized into three types denoted as GMOMS1, GMOMS2, and GMOMS3 based on the specific application of the graphene chemical potential (GCP). In GMOMS1, GCP was applied on both the CSRR and CS surfaces. In GMOMS2, GCP was applied to the CS surface and the surrounding outer region of the CSRR. In GMOMS3, GCP was applied to the CSRR and the surrounding outer region of the CSRR surface. The results show that all three designs exhibit high relative sensitivity, with the maximum values ranging from 227 GHz/RIU achieved by GMOMS1 to 4318 GHz/RIU achieved by GMOMS3. The FOM values achieved for all the designs range from 2.038 RIU-1 achieved by GMOMS2 to 31.52 RIU-1 achieved by GMOMS3, which is considered ideal in this paper.

Microbiological assessment of wastewater of milk processing enterprise

Recently, microbiological methods of wastewater treatment have been increasingly used. Microbiological destruction of a wide range of polycarbon organic compounds occurs due to the formation of a microbial sequence. The sequence consists in the fact that the end products (exometabolites) of “primary” destructive microorganisms are the primary substrates for “secondary” destructive microorganisms. The purpose of the work was to conduct a microbiological assessment of industrial wastewater from the fi ltration pond of a dairy processing enterprise using a biological purifi cation system. The proposed concept is a spatial sequence for the treatment of wastewater containing a wide range of organic substances of high concentration. The essence of the biological purifi cation system was the introduction of microbiological preparations into wastewater according to an individually developed technology. At the same time, air was additionally injected into the water column by an aerator. Wastewater sampling was carried out in accordance with the general requirements for surface waters according to National State Standard 31861-2012. Sample preparation and research were carried out using standard techniques. The wastewater of milk processing enterprises contains a signifi cant amount of proteins. During the decomposition of the protein the process of ammonifi cation occurs, i.e. the splitting of amino groups and their accumulation in the medium in the form of NH4 or NH3, these compounds alkalize the medium, which explains the increase in pH. The conducted sanitary and microbiological studies of wastewater and biofi lm using a biological wastewater treatment system of the milk processing enterprise indicate that a decrease in the concentration of organic matter is a consequence of the positive redox potential of the medium. The increased value of the redox potential means the decrease in the concentration of organic compounds in wastewater, which is an indicator of the effectiveness of treatment.