Wastewater Treatment Technologies Research Articles

Ecotoxicological study of seven pharmaceutically active compounds: Mixture effects and environmental risk assessment

Pharmaceutically active compounds (PhACs) have been detected in several aquatic compartments, which has been of environmental concern since PhACs can cause adverse effects on the aquatic ecosystem at low concentrations. Despite the variety of PhACs detected in surface water, ecotoxicological studies are non-existent for many of them, mainly regarding their mixture. In addition, water bodies can continuously receive the discharge of raw or treated wastewater with micropollutants. Thus, PhACs are subject to mixture and interactions, potentiating or reducing their toxicity. Therefore, the present study evaluated the toxicity on Aliivibrio fischeri of seven PhACs, which still needs to be explored in the literature. The effects were evaluated for the PhACs individually and for their binary and tertiary mixture. Also, the experimental effects were compared with the concentration addition (CA) and independent action (IA) models. Finally, an environmental risk assessment was carried out. Fenofibrate (FEN), loratadine (LOR), and ketoprofen (KET) were the most toxic, with EC50 of 0.32 mg L-1, 6.15 mg L-1 and 36.8 mg L-1, respectively. Synergistic effects were observed for FEN + LOR, KET + LOR, and KET + FEN + LOR, showing that the CA and IA may underestimate the toxicity. Environmental risks for KET concerning algae, and LOR e 17α-ethynylestradiol (EE2) for crustaceans and fish were high for several locations. Besides, high removals by wastewater treatment technologies are required to achieve the concentrations necessary for reducing KET and LOR risk quotients. Thus, this study contributed to a better understanding of the toxic interactions and environmental risks of PhACs.

Enhanced antifouling behavior and phosphorus removal in a gravity-driven electrochemical dynamic membrane bioreactor (EDMBR) process: Performance and mechanisms

Gravity-driven dynamic membrane bioreactor (DMBR) process has emerged as a promising wastewater treatment technology. However, long dynamic membrane (DM) formation time, membrane fouling and low phosphorus removal have limited its widespread application. A novel gravity-driven electro-DMBR (EDMBR) using stainless-steel meshes as the anodic membrane and graphite plates as the cathodes was developed for domestic wastewater treatment, with process performance, DM properties and energy consumption compared with a control DMBR without external voltage applied. Electrostatic adsorption between negatively charged foulants and positively charged anodic membrane shortened DM formation time to less than 4 min. Afterwards, electro-oxidation effect and biodegradation effect resulted from the enrichment of electroactive microorganisms (such as Pseudomonas, Acinetobacter, Exiguobacterium) ensured continuous degradation of attached foulants and maintained a thin and well-structured DM layer, showing higher stable flux and reduced cleaning frequency at the voltage of 1.2 V and 1.6 V compared to the control DMBR. The electro-coagulation (EC) effect originated from iron releasing modified the sludge properties and enhanced phosphorus removal (74 %-87 %). Moreover, the EDMBR with higher permeability and treatment capacity resulted in lower energy consumption (0.41–0.44 kWh/m3) compared to the DMBR (0.50 kWh/m3). The results provide new insights into sustainable operation of the EDMBR process towards lower energy demand and less maintenance requirement.

Interplay of Na Substitution in Magnetic Interaction and Photocatalytic Properties of Ca1-xNaxTi0.5Ta0.5O3 Perovskite Nanoparticles.

This research paper delves into the enhancement of wastewater treatment through the design and synthesis of advanced photocatalytic materials, focusing on the effects of sodium (Na) substitution in Ca1-xNaxTa0.5Ti0.5O3 perovskites. By employing various analytical techniques such as X-ray diffraction, Field Emission Scanning Electron Microscopy, Transmission Electron Microscopy and UV-vis spectroscopy, the study examines the transition of these perovskites from tetragonal to orthorhombic structures and observes a reduction in Ca content with Na substitution, which also favors the cubic phase formation and inhibits secondary phases. Significantly, magnetic property analysis uncovers an unexpected ferromagnetic ordering in these perovskites, including compositions traditionally viewed as non-magnetic. The photocatalytic tests reveal a significant improvement in degrading Rhodamine B dye under visible light, particularly in samples with higher Na levels, attributed to enhanced light absorption and efficient electron processes. The study highlights the optimal Na substitution level for peak photocatalytic performance, offering valuable insights into the complex interplay between structural, magnetic, and photocatalytic properties of these perovskites, and their potential in various applications, thereby contributing to the advancement of wastewater treatment technologies.

Evaluation of a Greenhouse Ecosystem to Treat Craft Beverage Wastewater

An aerated greenhouse ecosystem, often referred to as a Living Machine®, is a technology for biological wastewater treatment within a greenhouse structure that uses plants with their roots submerged in the wastewater. This system has a small footprint relative to traditional onsite wastewater treatment systems and constructed wetland, can treat high-strength wastewater, and can provide a high level of treatment to allow for reuse for purposes such as irrigation, toilet flushing, and landscape irrigation. Synthetic and actual craft beverage wastewaters (wastewater from wineries, breweries, and cideries) were examined for their treatability in bench-scale greenhouse ecosystems. The tested wastewater was high strength with chemical oxygen demands (COD) concentrations of 1120 to 15,000 mg/L, total nitrogen (TN) concentrations of 3 to 45 mg/L, and total phosphorus (TP) concentrations of 2.3 to 90 mg/L. The COD, TN, and TP concentrations after treatment ranged from below 125 to 560 mg/L, 1.5 to 15 mg/L, and below 0.25 to 7.8 mg/L, respectively. The results confirm the ability of the aerated greenhouse ecosystem to be a viable treatment system for craft beverage wastewater and it is estimated to require 54 and 26% lower hydraulic retention time than an aerobic lagoon and a low temperature, constructed wetland, respectively, the types of systems that would likely be used for this type of wastewater for onsite locations.

From Origins to Impacts: A Comprehensive Review of Microplastics in Freshwater Environments

Microplastics are plastic particles of dimensions less than 5mm, increasingly recognized as omnipresent contaminants in freshwater systems. These small particles are sourced from microbeads provided by personal care products, industrial abrasives, and other secondary sources formed by the degradation of larger plastic items. The microplastics are contaminated in freshwater environments through runoff, atmospheric deposition, and the discharge of water treatment processes. The presence of microplastics in freshwater has greater potential to cause harm to aquatic environments and human health. The primary objective of this paper is to identify the microplastic pollution in freshwater resources and classify the sources of this pollution in freshwater resources, including both primary and secondary microplastics, and to evaluate the ecological impact of microplastics and their potential health risks to humans through food chain transfer. This review synthesizes the most recent findings on sources, impacts, and potential mitigation measures of microplastic pollution in freshwater ecosystems to emphasize the attentive work needed urgently in our efforts to conquer the environmental challenge. The mitigation strategies in practice thus focus on policy implementation and correct technology in wastewater treatment, raising public awareness to minimize the use of plastics and encourage good waste management. However, studies with much detail are still required to develop systematic methodologies for microplastic analysis and go far enough to find long-term solutions

Nitrogen-doped iron-manganese porous carbon particle electrodes for electrocatalytic degradation of tetracycline: Interfacial reaction mechanisms

In this study, nitrogen-doped porous carbon-supported iron-manganese microspheres (FeMn@NC-700) were successfully synthesized and employed as three-dimensional particle electrodes (3DPE) for electro-oxidative of tetracycline (TCH) in water. FeMn@NC-700 exhibited stable catalytic activity and effective TCH removal capabilities under complex water quality conditions and varying pH levels. Under optimized conditions, the 3D/FeMn@NC-700 system reduced the TCH concentration from an initial 20 mg/L to 0.96 mg/L within 60 min, achieving a 95.23 %removal efficiency with an energy consumption of only 10.05 kWh/m3. The outstanding electrocatalytic activity of the 3D/FeMn@NC-700 system was attributed to the dynamic redox cycling between the Fe and Mn species on the 3DPE surface. Radical quenching experiments and electron paramagnetic resonance (EPR) analysis identified the predominant role of singlet oxygen (1O2), effectively removing TCH with the assistance of hydroxyl radicals (·OH) and superoxide anions (O2·-). The degradation pathways of major intermediate products of TCH were proposed, along with a toxicity assessment. In conclusion, the 3D/FeMn@NC-700 system represents a reliable and cost-effective technology for TCH wastewater treatment.

WASTEWATER TREATMENT BY USING BIOSYNTHESIZED NANOPARTICLES

Biosynthesized nanoparticles are a viable and sustainable approach for treating wastewater. They provide an environmentally acceptable alternative to traditional chemical synthesis processes. This review examines explicitly the production, use, and environmental consequences of nanoparticles created by biological methods, such as plant-mediated and microbial synthesis. The main aim of the review is to conduct a thorough assessment of the existing research on biosynthesized nanoparticles, focusing on identifying significant patterns, progress, and areas of knowledge lacking in the literature. The review consolidates results from current investigations, emphasizing the efficacy of these nanoparticles in eliminating organic pollutants, heavy metals, and other impurities from wastewater. The study also investigates the better characteristics of biosynthesized nanoparticles, including their reduced size, increased stability, and improved photoluminescence. These traits enhance their effectiveness in environmental cleanup. Nevertheless, the study highlights notable deficiencies in the existing body of research regarding the enduring ecological consequences and feasibility of implementing these environmentally friendly synthesis techniques on a large scale in industrial settings. The analysis continues by highlighting the necessity of consistent synthesis techniques and advocating for additional research on biosynthesized nanoparticles' scalability and long-term impacts. These findings emphasize the capability of biosynthesized nanoparticles to improve wastewater treatment technologies and support sustainable environmental management. They also emphasize the significance of ongoing multidisciplinary research in this rapidly developing field.

A highly efficient and stable PtNi bimetallic nanoparticles modified on Mo2C decorated N-doped carbon flowers catalysts for the remediation of environmental pollutants

The unregulated discharge of nitroaromatics (NAs) and organic dye contaminants into aquatic ecosystems is a growing global concern, highlighting the urgent need for the development of effective wastewater treatment technology. In this study, we prepared Mo2C decorated on N- doped carbon flowers supported with PtNi bimetallic (PtxNiy@Mo2C/NCF) nanoparticles using the self-polymerization of dopamine and followed by the chemical reduction methods. These catalysts, with varying Pt:Ni ratios, were designed for the highly efficient catalytic reduction of NAs and rhodamine b (RhB) under the mild reaction conditions. The HR-TEM images confirmed the formation of spherical PtNi bimetallic NPs with an average diameter of 1.68 ± 0.6 nm. The prepared PtxNiy@Mo2C/NCF catalysts exhibited significantly higher catalytic efficiency for 4-nitrophenol (4-NP) reduction compared to their respective monometallic counterparts using NaBH4. Particularly, the Pt0.75Ni0.25@Mo2C/NCF catalyst showed superior catalytic activity with the apparent rate constant (kapp: 0.6703 min−1) and TOF (17.0 × 10−7 mol mg−1 min−1) and high recyclability over eight consecutive recycles. Furthermore, the Pt0.75Ni0.25@Mo2C/NCF catalyst also exhibited high catalytic activity for other NAs and RhB dye reduction with excellent yields. This enhanced catalytic activity of Pt0.75Ni0.25@Mo2C/NCF catalyst could be ascribed to the synergistic effect of the bimetallic systems, leading to more efficient reactions. Additional experiments were conducted on a fixed bed reactor to demonstrate that the Pt0.75Ni0.25@Mo2C/NCF catalyst effectively reduce both 4-NP and RhB dye over 15 successive runs. This work may pave the way for using PtxNiy@Mo2C/NCF catalysts in various wastewater treatment applications.

Removal of oxytetracycline from pharmaceutical wastewater using kappa carrageenan hydrogel

This study investigated the adsorption of Oxytetracycline (OTC) from pharmaceutical wastewater using a kappa carrageenan based hydrogel (KPB). The aim of the present study was to explore the potential of KPB for long-term pharmaceutical wastewater treatment. A sustainable adsorbent was developed to address oxytetracycline (OTC) contamination. The hydrogel’s structural and adsorption characteristics were examined using various techniques like Scanning Electron Microscope (SEM), Fourier Transform Infrared (FTIR), X-ray powder diffraction (XRD), and kinetic models. The results revealed considerable changes in the vibrational modes and adsorption bands of the hydrogel, suggesting the effective functionalization of Bentonite nano-clay. Kappa carrageenan based hydrogel achieved the maximum removal (98.5%) of OTC at concerntration of 40 mg/L, pH 8, cotact time of 140 min and adsorbent dose of 0.1 g (KPB-3). Adsorption of OTC increased up to 99% with increasing initial concentrations. The study achieved 95% adsorption capacity for OTC using a KPB film at a concentration of 20 mg/L and a 0.1 g adsorbent dose within 60 min. It also revealed that chemisorptions processes outperform physical adsorption. The Pseudo-Second-Order model, which emphasized the importance of chemical adsorption in the removal process, is better suited to represent the adsorption behavior. Excellent matches were found that R2 = 0.99 for KPB-3, R2 = 0.984 for KPB-2 and R2 = 0.989 for KPB-1 indicated strong chemical bonding interactions. Statisctical analysis (ANOVA) was performed using SPSS (version 25) and it was found that pH and concentration had significant influence on OTC adsorption by the hydrogel, with p-values less than 0.05. The study identified that a Kappa carrageenan-based hydrogel with bentonite nano-clay and polyvinyl alcohol (PVA) can efficiently remove OTC from pharmaceutical effluent, with a p-value of 0.054, but weak positive linear associations with pH, temperature, and contact time. This research contributed to sustainable wastewater treatment and environmental engineering.

The fate and behavior mechanism of antibiotic resistance genes in different-sized aerobic granular sludge under antibiotics pressure

Aerobic granular sludge (AGS) is a promising wastewater treatment technology. Studying the distribution of ARGs in different-sized AGS under antibiotic pressure is crucial for ARGs risk assessment and control technology development. Herein, the risk of intracellular ARGs (iARGs) in viable/dead bacteria within small (0–1 mm), moderate (1–2 mm), and big (2–3 mm) AGS (S/M/B-AGS) were clarified under tetracycline and sulfadiazine stress. Besides, the potential mechanism of ARGs enrichment differences in S/M/B-AGS was revealed. M−AGS had the lowest iARGs risk (30–60 days) in both viable (3.3E+08 copies/g-dw) and dead (6.7E+08 copies/g-dw) bacteria, averaging 29.8 % lower than B-AGS and 72.1 % lower than S-AGS, respectively. The average changes in abundance of the top 20 genera in S/M/B-AGS were 3.0 %, 2.6 %, and 2.9 % from day 30 to day 60, respectively. The complexity between ARGs and bacterial communities was highest in S-AGS, followed by B-AGS and M−AGS. Among the 19–20 identified hosts in S/M/B-AGS, only 11 hosts were shared. Extracellular polymeric substances (EPS) and protein, particularly those with α-helical structure, adsorbed antibiotics and envelop bacteria, enhancing mass transfer resistance and effectively reducing antibiotic stress on bacteria. M−AGS exhibited the highest contents of EPS and protein compared to S/B-AGS, potentially explaining the lowest iARGs risk observed. Overall, this study discovered the different behaviors of iARGs in viable/dead bacteria in S/M/B-AGS, offering a novel perspective on granular size modulation strategies to reduce ARGs risk.

An Overview on Oily Wastewater Treatment Technology for Ships

An Overview on Oily Wastewater Treatment Technology for Ships

Performance evaluation and microbial community analysis of a continuous stirred tank reactor–anaerobic ceramic membrane bioreactor system for practical swine wastewater treatment

To treat swine wastewater from a practical piggery, a continuous stirred tank reactor (CSTR)–anaerobic ceramic membrane bioreactor (AnCMBR) was operated for 201 days. A high chemical oxygen demand (COD) removal efficiency of 95 % and biogas production rate of 0.31 L/L·d were achieved at an organic loading rate (OLR) of 1.19 g-COD/L·d. Although the free ammonia concentration reached a maximum of 200 mg/L during the last operational phase, no evident inhibitory effect on AnCMBR performance was observed. Microbial community analyses indicated that six bacterial phyla were responsible for the hydrolysis, acidification, and fermentation of organics and environmental stabilization. Hydrotrophic methanogenic archaea were dominant, indicating that the main methane production pathway involved the use of H2 and CO2 as substrates. The results demonstrated that CSTR–AnCMBR systems exhibit excellent organics removal performance and energy recovery at high organic concentrations and possess strong anti-shock ability. Thus, they represent alternative green and sustainable anaerobic technologies for practical swine wastewater treatment.

Study on Methylene Blue Adsorption Properties of Biochar/Montmorillonite Composites

The textile printing and dyeing industry, as one of the important pillars of the global economy, has become an environmental problem that needs to be solved because of the increasingly serious pollution of dye wastewater generated during its production process. Dye wastewater not only contains high concentrations of organic dyes, but also often accompanied by heavy metal ions, additives and salts and other pollutants, if discharged directly without effective treatment, will seriously pollute the water body, destroying the ecological balance, and affecting the survival and health of human beings and aquatic organisms. In order to deal with the problems of serious pollution, large discharge and high cost of dye wastewater, it is necessary to develop an efficient, economic and environmentally friendly wastewater treatment system. It is particularly important to develop efficient, economical and environmentally friendly wastewater treatment technologies. Adsorption is considered as a promising method for wastewater treatment. In this study, we focused on the development of new and efficient adsorbent materials. Taking methylene blue, a typical dye, as an example, we skillfully composited modified biochar with montmorillonite, a natural mineral material, through pyrolysis and intercalation strategies, and conducted in-depth investigations on the effects of the composites on the adsorption of methylene blue in water, the factors affecting the regeneration performance of the adsorbents, and the thermodynamic characteristics of the adsorption. The effect of the composite material on the adsorption of methylene blue in water, the factors affecting the regeneration performance of the adsorbent and the adsorption thermodynamic characteristics were investigated in depth, with a view to providing certain theoretical and practical references for the effective treatment of dye wastewater.

High-efficiency flocculation of Leptosphaerulina australis J-22 to Chlorella vulgaris: Characteristics, optimal parameters and mechanisms

Fungal flocculation as an efficient technique to harvest microalgae can effectively preserve biomass and facilitate the creation of algae-fungi aggregates. In this study, the efficiency, characteristics and the optimal parameters of flocculation of Leptosphaerulina australis J-22 that isolated from a municipal wastewater treatment plant (MWWTP) were evaluated. The flocculation process and mechanisms were also analyzed through metabolomics and transcriptomics. The results showed that the flocculation efficiency of Leptosphaerulina australis J-22 was up to 97 % within 2 h with the optimal flocculation parameters of 2.5 g/L mycelium pellets at 197 rpm for 9 h. It was observed that the network structure of mycelium facilitated the C. vulgaris flocculation, while the flocculating substances such as amino acids and their structural analogs, as well as metabolites with active groups secreted by fungi had no effects on the growth of C. vulgaris. The analysis of metabolomics and transcriptomics illustrated that the flocculation processes were regulated by multiple pathways such as substance synthesis, substance transport and potential changes, etc. Leptosphaerulina australis flocculated C. vulgaris with high efficiency, offered reference for developing new symbiotic bacteria-algae wastewater treatment technologies.

Performance of a pilot-scale microbial electrolysis cell coupled with biofilm-based reactor for household wastewater treatment: simultaneous pollutant removal and hydrogen production.

The septic tank is the most commonly used decentralized wastewater treatment systems for household wastewater treatment in on-site applications. The removal rate of various pollutants is lower in different septic tank configurations. The integration of a microbial electrolysis cells (MEC) into septic tank or biofilm-based reactors can be a green and sustainable technology for household wastewater treatment and energy production. In this study, a 50-L septic tank was converted into a 50-L MEC coupled with biofilm-based reactor for simultaneous household wastewater treatment and hydrogen production. The biofilm-based reactor was integrated by an anaerobic packed-bed biofilm reactor (APBBR) and an aerobic moving bed biofilm reactor (aeMBBR). The MEC/APBBR/aeMBBR was evaluated at different organic loading rates (OLRs) by applying voltage of 0.7 and 1.0V. Result showed that the increase of OLRs from 0.2 to 0.44kg COD/m3 d did not affect organic matter removals. Nutrient and solids removal decreased with increasing OLR up to 0.44kg COD/m3 d. Global removal of chemical oxygen demand (COD), biochemical oxygen demand (BOD), total nitrogen (TN), ammoniacal nitrogen (NH4+), total phosphorus (TP) and total suspended solids (TSS) removal ranged from 81 to 84%, 84 to 85%, 53 to 68%, 88 to 98%, 11 to 30% and 76 to 88% respectively, was obtained in this study. The current density generated in the MEC from 0 to 0.41 A/m2 contributed to an increase in hydrogen production and pollutants removal. The maximum volumetric hydrogen production rate obtained in the MEC was 0.007 L/L.d (0.072 L/d). The integration of the MEC into biofilm-based reactors applying a voltage of 1.0V generated different bioelectrochemical nitrogen and phosphorus transformations within the MEC, allowing a simultaneous denitrification-nitrification process with phosphorus removal.

Sludge Recycling from Non-Lime Purification of Electrolysis Wastewater: Bridge from Contaminant Removal to Waste-Derived NOX SCR Catalyst

Catalysts for the selective catalytic reduction (NOX SCR) of nitrogen oxides can be obtained from sludge in industrial waste treatment, and, due to the complex composition of sludge, NOX SCR shows various SCR efficiencies. In the current work, an SCR catalyst developed from the sludge produced with Fe/C micro-electrolysis Fenton technology (MEF) in wastewater treatment was investigated, taking into account various sludge compositions, Fe/C ratios, and contaminant contents. It was found that, at about 300 °C, the NOX removal rate could reach 100% and there was a wide decomposition temperature zone. The effect of individual components of electroplating sludge, i.e., P, Fe and Ni, on NOX degradation performance of the obtained solids was investigated. It was found that the best effect was achieved when the Fe/P was 8/3 wt%, and variations in the Ni content had a limited effect on the NOX degradation performance. When the Fe/C was 1:2 and the Fe/C/P was 1:2:0.4, the electroplating sludge formed after treatment with Fe/C MEF provided the best NOX removal rate at 100%. Moreover, the characterization results show that the activated carbon was also involved in the catalytic reduction degradation of NOX. An excessive Fe content may cause agglomeration on the catalyst surface and thus affect the catalytic efficiency. The addition of P effectively reduces the catalytic reaction temperature, and the formation of phosphate promotes the generation of adsorbed oxygen, which in turn contributes to improvements in catalytic efficiency. Therefore, our work suggests that controlling the composition in the sludge is an efficient way to modulate SCR catalysis, providing a bridge from contaminant-bearing waste to efficient catalyst.

Overlooked role of CO3·− reactivity with different dissociation forms of organic micropollutants in degradation kinetics modeling: A case study of fluoxetine degradation in a UV/peroxymonosulfate system

Selective oxidizing agent carbonate radical (CO3•–) is an important secondary radical in radical-based advanced oxidation technology for wastewater treatment. However, the role of CO3•– in removing ionizable organic micropollutants (OMs) under environmentally relevant conditions remains unclear. Herein we investigated CO3•– effect on degradation kinetics of fluoxetine in UV/peroxymonosulfate (PMS) system based on a built radical model considering CO3•– reactivity differences with its different dissociation forms. Results revealed that the model, which incorporated CO3•– selective reactivity (with determined second-order rate constants, ksrc,CO3·−, of 7.33 ×106 and 2.56 ×108 M–1s–1 for cationic and neutral fluoxetine, respectively) provided significantly more accurate predictions of fluoxetine degradation rates (k). A good linear correlation was observed between ksrc,CO3·− from experiments and literatures for 24 ionizable OMs and their molecular orbital energy gaps and oxidation potentials, suggesting the possible electron transfer reaction mechanism. Cl– slightly reduced the degradation rates of fluoxetine owing to rapid transformation of Cl• with HCO3− into CO3•–, which partially compensated for the quenching effects of Cl− on HO• and SO4•–. Dissolved organic matter significantly quenched reactive radicals. The constructed kinetic model successfully predicted fluoxetine degradation rates in real waters, with CO3•– being the dominant contributor (∼90 %) to this degradation process.

Adsorption of Polycyclic Aromatic Hydrocarbons from Wastewater Using Iron Oxide Nanomaterials Recovered from Acid Mine Water: A Review

Polycyclic aromatic hydrocarbons (PAHs) are a group of organic pollutants known for their persistence and potential carcinogenicity. Effective removal techniques are required since their presence in wastewater poses serious threats to human health and the environment. In this review study, iron oxide nanomaterials (IONs), a by-product of mining operations, recovered from acid mine water are used to investigate the adsorption of PAHs from wastewater. The mechanisms of PAH adsorption onto IONs are investigated, with a focus on the effects of concentration, temperature, and pH on adsorption efficiency. The better performance, affordability, and reusable nature of IONs are demonstrated by comparative studies with alternative adsorbents such as activated carbon. Economic and environmental ramifications highlight the benefits of employing recovered materials, while case studies and real-world applications show how effective IONs are in removing PAHs in the real world. This review concludes by discussing potential future developments in synthesis processes, areas for more research, and emerging trends in nanomaterial-based adsorption. This research intends to contribute to the development of more effective and sustainable wastewater treatment technologies by offering a thorough assessment of the present and future potential of employing IONs for PAH removal from wastewater.

The efficacy of integrated vermifiltration technology for treatment of food analysis laboratory wastewater

The macrophyte-assisted vermifiltration (MAVF) technology was applied for treatment of food analysis laboratory wastewater at Industrial Technology Institute (ITI), Sri Lanka for the first time. Three laboratory-scale sub-surface vertical flow units were established:1) without earthworms and plants (Control unit), 2) with earthworms (Eisenia fetida) (vermi-filtration unit (VF unit), 3) with both earthworms and macrophytes (Canna indica) (MAVF unit). Wastewater was fed batch-wise with a feeding rate of 10 mL/min and seven days hydraulic retention time (HRT) for eight consecutive batches. Physiochemical parameters, Chemical Oxygen Demand (COD), Total Phosphorus (TP), Total Nitrogen (TN), pH, of the influent and effluent of all three units were analyzed to investigate the treatment efficiencies. One-Way ANOVA was performed to evaluate the significant differences in treatment efficiencies. The mean COD removal efficiencies of the control unit, VF unit, and MAVF unit were 60.2 % ± 10.7, 71.6± 8.07 %, and 72.0 % ± 8.86, respectively. Average TN removal efficiencies of the control unit, VF unit, and MAVF unit were 8.05 % ± 5.75, 10.9±6.4 %, and 24.9 % ±12.84, respectively. Average TP removal efficiencies were 35.84 % ± 17.5, 35.84 % ± 17.5 %, and 40.0 % ±16.76, respectively. The COD removal displayed promising results, whereas the means for enhancing TP and TN removal should be further studied. The findings of this study sensitizes the testing laboratories to go green by adopting in-house cost effective laboratory wastewater treatment systems.

Illuminating the role of powder carrier materials in shaping sludge aggregation in wastewater treatment: Insights from extended operation performance to microbial response mechanism

This study uncovered the response of novel micro-granule wastewater treatment technology to different powder carrier materials. Characteristics and distinctions among different systems were assessed based on process performance, sludge aggregation capacity, and microbial metabolism. Zeolite carrier system exhibited remarkable nitrogen removal efficiency of 89.6 ± 0.9 %, while diatomite carriers, in conjunction with intermittent aeration, enhanced simultaneous nitrification and denitrification from 2.6 % to 27.1 %. Iron-based carriers demonstrated efficient phosphorus removal (94.7 ± 1.2 %) through both chemical and microbial pathways. Specific surface area, pore structure and biocompatibility of powder carriers determined the formation and size of micro-granules. Tryptophan-like substances, C-(C/H), and Npr in extracellular polymeric substances strongly correlated with sludge hydrophobicity and granulation. Significant enrichment in norank_Comamonadaceae and Nitrosomonas in zeolite powder carrier system promoted partial nitrification and endogenous denitrification. Differences in metabolic pathways elucidated the up-regulation of amino acid synthesis, energy metabolism, and membrane transport as potential mechanisms driving micro-granule formation and efficient treatment performance.