Prospects for humic acids treatment and recovery in wastewater: A review

Crystalline carbon nitride derived self-assembly composite membranes with enhanced self-cleaning performance toward dye/salt separation

Membrane technology can realize the sustainable management of textile wastewater through dye/salt separation, but its practical implementation has long been hampered by membrane fouling. This work was to develop a novel carbon nitride based two-dimensional (2D) self-assembled membrane for efficient dye/salt separation with excellent photocatalytic self-cleaning performance toward azo dyes (e.g., methyl blue), anthraquinone dyes (e.g., reactive blue 19) and natural organic matters (e.g., humic acid). Specifically, conventional graphite carbon nitride (g-C3N4), poly triazine imide (PTI) and the composites of iron oxide doped PTI (PTI-Fe2O3) were comparatively investigated for manipulating the lamellar self-catalytic membrane through facile vacuum filtration. The considerable separation factors of sodium chloride to methyl blue (Ssalt/dye) of 76.97, 80.72, and 74.33 were obtained by g-C3N4, PTI, and PTI-Fe2O3, respectively. The generation of radicals and non-radicals were triggered by light irradiation and was accelerated by PTI compared to g-C3N4, resulting in the better flux recovery rate (FRR) of 95.7 % for PTI membrane than that of g-C3N4 membrane (74.4 %). Besides, the introduction of iron oxide enables the enhanced self-cleaning performance by coupling photocatalytic and Fenton-like process, leading to the highest FRR value of 99.4 %. Meanwhile, the fabricated membranes demonstrate remarkable stability (FRR ≥ 80 %) during prolonged operation (64 h) to both simulated and real textile wastewater, indicating that it can a promising alternative membrane material for textile wastewater management.

Escherichia coli migration in saturated porous media: Mechanisms of humic acid regulation

The regulatory behavior of humic acid (HA) on the migration of Escherichia coli (E.coli) in saturated porous media has garnered considerable research interest. Although prior studies have confirmed that HA indeed facilitates the migration of E. coli in saturated porous media, investigating the migration process and regulatory mechanisms at the microscale remains challenging. This study compared the differences in the migration behavior of E. coli in saturated porous media under conditions with and without HA, revealing the dynamic mechanism by which HA regulates microbial migration through the "bacterium-medium-solution" triple interface interaction. The results indicated that E. coli achieves the transition of the "run-tumble" movement pattern (run ≈ 1 s, tumble ≈ 0.1 s) through flagellar morphological regulation, thus completing directed migration in a complex pore network. The addition of HA significantly enhanced the migration rate of E. coli, with an increase of at least 5 %. For the bacteria, HA induced the restructuring of lipopolysaccharides on the bacterial surface, altered the surface Zeta potential of the bacteria, and promoted the formation of stable hetero-aggregates between bacteria and HA. At the medium interface, HA modifies the surface charge of the medium, regulates pore structure, and increases hydrophilicity through the adsorption-desorption mechanism. In the solution system, the dissociation characteristics of HA's carboxyl and phenolic hydroxyl groups dynamically regulated the solution's ionic strength and pH value, creating a chemical microenvironment suitable for bacterial migration. This study systematically revealed the multi-dimensional mechanisms by which HA regulates microbial transport through molecular interface engineering. It provides theoretical support for establishing predictive models of pathogen migration in groundwater systems and offers important guidance for optimizing microbial control strategies in water treatment processes.

A polyethyleneimine-coated thermally-oxidized graphitic-carbon nitride adsorbent for the removal of organic pollutants

Negatively charged organic pollutants in water are responsible for a large range of public health and ecological issues. Low-cost and low-toxicity graphitic carbon nitride (CN), with its abundant functional groups and surface defects, is a promising material for the removal of organic molecules by adsorption. However, basic synthesis methods for CN often result in a material with morphology and electric charge that are suboptimal for interacting with negatively charged pollutants. Here, an adsorbent was prepared by thermally oxidizing a tubular CN precursor and then coating the resulting flake-shaped material (FCNO) with the polycationic polymer polyethyleneimine (PEI). The resulting adsorbent, FCNO550-PEI, removed humic acid (HA), a widespread problematic organic molecule, as well as the common toxic anionic dye Congo red (CR). FCNO550-PEI was superior to other CN-based adsorbents previously reported in the literature with maximum adsorption capacities according to the Sips isotherm model for HA and CR of 437.1 mg/g and 1430.3 mg/g, respectively. In addition, FCNO550-PEI could adsorb HA and CR from different types of water and was reusable. Besides electrostatic interactions and hydrogen bonds between PEI and the pollutants, HA and CR adsorption was enabled by π-π interactions with the FCNO support itself. The high efficiency of FCNO550-PEI for the removal of HA and CR highlights its potential for water treatment applications.

Integration of bioflocculation with anaerobic digestion guided by physicochemical profiling enhances valorization potential of domestic wastewater

Domestic wastewater is a dilute, variable, and complex carbon source for bioprocessing. Despite various treatment technologies, tailored bioprocessing and profiling studies are needed to fully explore its potential. Efficient integration of bioflocculation with anaerobic digestion (AD) is evaluated as a potential platform for small molecules and biogas recovery. Bioflocculation of low strength domestic wastewater (COD ∼ 0.1 g/L) using a bioflocculant resulted in clear water and flocculated sludge, having 30-90 fold increase in Chemical Oxygen Demand (COD). Alkali pretreatment of flocculated sludge (COD ∼ 10 g/L) significantly enhanced biogas production, resulting in a methane yield of 49 %. 1H NMR and GC-MS based profiling demonstrated the desirable impact of bioflocculation and alkali treatment on small molecule abundance. This study establishes an integrated approach that combines bioflocculation, alkali pretreatment, and AD, guided by small molecule profiling, as an effective process for valorizing domestic wastewater into biogas and recoverable organic molecules.

Effective Inhibitor Removal from Wastewater Samples Increases Sensitivity of RT-dPCR and Sequencing Analyses and Enhances the Stability of Wastewater-Based Surveillance

Wastewater-based surveillance (WBS) is a proven tool for monitoring population-level infection events. Wastewater contains high concentrations of inhibitors, which contaminate the total nucleic acids (TNA) extracted from these samples. We found that TNA extracts from raw influent of Berlin wastewater treatment plants contained highly variable amounts of inhibitors that impaired molecular analyses like dPCR and next-generation sequencing (NGS). By using dilutions, we were able to detect inhibitory effects. To enhance WBS sensitivity and stability, we applied a combination of PCR inhibitor removal and TNA dilution (PIR+D). This approach led to a 26-fold increase in measured SARS-CoV-2 concentrations, practically reducing the detection limit. Additionally, we observed a substantial increase in the stability of the time series. We define suitable stability as a mean absolute error (MAE) below 0.1 log10 copies/L and a geometric mean relative absolute error (GMRAE) below 26%. Using PIR+D, the MAE could be reduced from 0.219 to 0.097 and the GMRAE from 65.5% to 26.0%, and even further in real-world WBS. Furthermore, PIR+D improved SARS-CoV-2 genome alignment and coverage in amplicon-based NGS for low to medium concentrations. In conclusion, we strongly recommend both the monitoring and removal of inhibitors from samples for WBS.

The competition of humic acid aggregation and adsorption on clay particles and its role in retarding heavy metal ions

Humic acid (HA) is of great importance in controlling the fate of heavy metals (HMs), however, the pivotal influence of HA aggregation within the HA-clay-HM ternary system on retarding HM mobility remains obscure. This study performed molecular dynamics simulations to delve into the consequences of HA aggregation on the environmental behavior of Cd2+ and Pb2+ (0.1-0.6 M) in the co-existence of illite particles. HA can readily aggregate into clusters, adhering to the illite surface or freely dispersing in the solution. These HA clusters significantly modulate HM mobility, contingent upon their location, arrangement, and interaction with illite. Consequently, HA exhibited a pronounced retardation effect on HM migration, stemming from the competition between HA aggregation and its adsorption on illite. Additionally, the retardation effect of HA aggregation was more obvious for Cd2+ (as compared to Pb2+), owing to its stronger interaction with the functional groups of HA. These findings contribute to the development of potential HA-based strategies for remediation of heavy metal-contaminated sites.

Pharmaceutical Removal with Photocatalytically Active Nanocomposite Membranes

The advancement of pharmaceutical science has resulted in the development of numerous tailor-made compounds, i.e., pharmaceuticals, tuned for specific drug targets. These compounds are often characterized by their low biodegradability and are commonly excreted to a certain extent unchanged from the human body. Due to their low biodegradability, these compounds represent a significant challenge to wastewater treatment plants. Often, these compounds end up in effluents in the environment. With the advancement of membrane technologies and advanced oxidation processes, photocatalysis in particular, a synergistic approach between the two was recognized and embraced. These hybrid advanced water treatment processes are the focus of this review, specifically the removal of pharmaceuticals from water using a combination of a photocatalyst and pressure membrane process, such as reverse osmosis or nanofiltration employing photocatalytic nanocomposite membranes.

Fertilising properties of materials based on opoka and waste concrete after sorption of humic substances from raw reject water

The treatment and reuse of wastewater in a strategic approach to mitigate water scarcity and its declining quality. Natural organic matter, particularly humic substances (HS) from decomposed plant and animal material, often determined the quality of treated wastewater. This study integrates HS recovery into conventional wastewater treatment, aligning with global trends towards carbon capture and storage. The efficacy of opoka (OP) and waste autoclaved aerated concrete (AAC) to sorb HS from the real reject water (RW) was evaluated. The analysis showed that fulvic acids comprised 89% of the organic matter in RW. OP and AAC demonstrated HS sorption capacities of 200 mg g⁻1. The metal concentrations in the post-sorbents remained within the regulatory limits set for fertilizers by Polish and EU standards. The materials were further tested for phytoactivity in hydroponic systems at different doses (0.05-25 g L-1).A more balanced ratio of ionic forms in the post-sorbents resulted in lower conductivity, improving their chemical stability and phytoactivity. Phytotoxicity studies indicated a that a concentration range of post-sorbents from 0.1 to 2.5 g L-1 was optimal for promoting the growth of most of the tested plants. This research highlights the potential of using post-sorbents as fertilizers, advancing sustainability by recovering HS from RW and supporting a circular economy approach.

Three-birds-with-one-stone: An eco-friendly and renewable humic acid-derived material application strategy for macrolide antibiotic detection and multifunctional composite film preparation

This research proposes a simple and novel strategy for the green detection of antibiotics along with the reduction of microplastic and humic acid (HA) hazards. The entire process is based on a single-step solvent-sieving method to separate HA into insoluble (IHA) and soluble (SHA) components, subsequently recombining and designing the application according to the original characteristics of selected fractions in accordance with the zero-waste principle. IHA was applied as a dispersive solid phase extraction (DSPE) sorbent without chemical modification for the enrichment of trace MACs in complex biological matrices. The recovery of MACs was 74.06-100.84 % in the range of 2.5-1000 μg∙kg-1. Furthermore, SHA could be combined with biodegradable polyvinyl alcohol (PVA) to prepare multifunctional composite films. SHA endows the PVA film with favorable mechanical properties, excellent UV shielding as well as oxidation resistance performance. Compared with pure PVA, the tensile strength, toughness, antioxidant and UV-protection properties were increased to 157.3 Mpa, 258.6 MJ·m-3, 78.6 % and 60 % respectively. This study achieved a green and economically valuable utilization of all components of waste HA, introduced a novel approach for monitoring and controlling harmful substances and reducing white pollution. This has significant implications for promoting sustainable development and recovering valuable resources.

Biopolymer-based beads for the adsorptive removal of organic pollutants from wastewater: Current state and future perspectives

Among biopolymer-based adsorbents, composites in the form of beads have shown promising results in terms of high adsorption capacity and ease of separation from the effluents. This review addresses the potential of biopolymer-based beads to remediate wastewaters polluted with emerging organic contaminants, for instance dyes, active pharmaceutical ingredients, pesticides, phenols, oils, polyaromatic hydrocarbons, and polychlorinated biphenyls. High adsorption capacities up to 2541.76 mg g-1 for dyes, 392 mg g-1 for pesticides and phenols, 1890.3 mg g-1 for pharmaceuticals, and 537 g g-1 for oils and organic solvents have been reported. The review also attempted to convey to its readers the significance of wastewater treatment through adsorption by providing an overview on decontamination technologies of organic water contaminants. Various preparation methods of biopolymer-based gel beads and adsorption mechanisms involved in the process of decontamination have been summarized and analyzed. Therefore, we believe there is an urge to discuss the current state of the application of biopolymer-based gel beads for the adsorption of organic pollutants from wastewater and future perspectives in this regard since it is imperative to treat wastewater before releasing into freshwater bodies.

Design and preparation of reticular superabsorbent hydrogel material with nutrient slow-release and high shear strength for ecological remediation of abandoned mines with steep slopes

In order to solve ecological remediation issues for abandoned mines with steep slopes, a kind of hydrogels with high cohesion and water-retaining were designed by inorganic mineral skeleton combining with polymeric organic network cavities. This eco-friendly hydrogel (MFA/HA-g-p(AA-co-AM)) was prepared with acrylic acid (AA)-acrylamide (AM) as network, which was grafted with humic acids (HA) as network binding point reinforcement skeleton and polar functional group donors, KOH-modified fly ash (MFA) as internal supporter. The maximum water absorption capacities were 1960 g/g for distilled water, which followed the pseudo-second-order model. This super water absorption was attributed to the first stage of 62 % fast absorption due to the high specific surface area, pore volume and low osmotic pressure, moreover, the multiple hydrophilic functional groups and network structure swell contributed to 36 % of the second stage slow adsorption. In addition, the pore filling of water in mesoporous channels contributed the additional 2 % water retention on the third stage. The high saline-alkali resistance correlated with the electrostatic attraction with MFA and multiple interactions with oxygen-containing functional groups in organic components. MFA and HA also enhanced the shear strength and fertility retention properties. After 5 cycles of natural dehydration and reabsorption process, these excellent characteristics of reusability and water absorption capacity kept above 97 %. The application of 0.6 wt% MFA/HA-g-p(AA-co-AM) at 15° slope could improve the growth of ryegrass by approximately 45 %. This study provides an efficient and economic superabsorbent material for ecological restoration of abandoned mines with steep slopes.

Integrating bioprocess and metagenomics studies to enhance humic acid production from rice straw

Rice straw burning annually (millions of tons) leads to greenhouse gas emissions, and an alternative solution is producing humic acid with high added-value. This study aimed to examine the influence of a microbial consortium and other additives (chicken manure, urea, olive mill waste, zeolite, and biochar) on the composting process of rice straw and the subsequent production of humic acid. Results showed that among the fungal species, Thermoascus aurantiacus exhibited the most prominent impact in expediting maturation and improving compost quality, and Bacillus subtilis was the most abundant bacterial species based on metagenomics analysis. The highest temperature, C/N ratio reduction, and amount of humic acid production (Respectively in lab 61 °C, 54.67%, 298 g kg-1 and in pilot level 65 °C, 72.11%, 310 g kg-1) were related to treatments containing these microorganisms and other additives except urea. Consequently, T. aurantiacus and B. subtilis can be employed on an industrial scale as compost additives to further elevate quality. Functional analysis showed that the bacterial enzymes in the treatments had the highest metabolic activities, including carbohydrate and amino acid metabolism compared to the control. The maximum enzymatic activities were in the thermophilic phase in treatments which were significantly higher than that in the control. The research emphasizes the importance of identifying and incorporating enzymatically active strains that are suitable for temperature conditions, alongside the native strains in decomposing materials. This strategy significantly improves the composting process and yields high-quality humic acid during the thermophilic phase.

A novel photo-enzyme platform based on non-metallic modified carbon nitride for removal of bisphenol A in water

A nonmetallic composite photocatalyst with 2D/2D structure was prepared by hydrothermal in-situ polymerization and used for the immobilization of cytochrome C (Cyt c). The photo-enzyme coupling system has a very high enzyme load, which can reach 528.29 mg g-1 after optimization. Compared with free Cyt c, Cytc/PEDOT/CN showed better enzymatic activity, stability and catalytic efficiency. Even after being stored at 100 °C for 60 min, the enzyme activity remained at 49.42 % and remained at 57.89 % after 8 cycles. Moreover, Cytc0.5/PEDOT3/CN showed excellent photocatalytic degradation performance in the degradation experiment of bisphenol A (BPA), reaching 68.22 % degradation rate within 60 min, which was 3.9 times higher than that of pure g-C3N4 and 1.61 times higher than that of pure PEDOT3/CN. This study shows that the introduction of conductive polymers is of great significance to the photo-enzyme coupling system and provides a new strategy for the treatment of phenol-containing wastewater.

Investigating the Impact of Humic Acid on Copper Accumulation in Sinonovacula constricta Using a Toxicokinetic-Toxicodynamic Model

In aquatic ecosystems, the interaction between heavy metals and dissolved organic carbon (DOC) plays a pivotal role in modifying the bioavailability of these metals. This study, employing a toxicokinetic-toxicodynamic model, delves into the interactive effects of humic acid (HA), a significant component of DOC, on the bioaccumulation and toxicity of copper (Cu) in the estuarine economic bivalve Sinonovacula constricta. Utilizing the stable isotope 65Cu as a tracer, we evaluated Cu uptake in S. constricta under varied DOC concentrations in a controlled laboratory setting. Our findings reveal that at DOC concentrations below 3.05 mg L-1, the bioavailability of Cu is reduced due to shifts in the speciation distribution of Cu, resulting in decreased bioaccumulation within S. constricta. Conversely, at DOC levels exceeding 3.05 mg L-1, the formation of colloidal Cu-HA complexes allows its entry into the bivalves' digestive system. Moreover, toxicity assays demonstrate an increase in S. constricta survival rates with higher DOC concentrations, suggesting a protective effect of DOC against Cu toxicity. The integration of accumulation and toxicity data infers that Cu-HA complexes, when ingested via the digestive tract, exhibit lower toxicity compared to Cu directly assimilated from the water phase. These findings emphasize the need to consider environmental DOC levels in assessing Cu pollution risks and provide insights for managing heavy metal toxicity in estuarine aquaculture.

A change in substance and microbial community structure during the co-composting of kitchen waste anaerobic digestion effluent, sewage sludge and Chinese medicine residue

Anaerobic digestion is a resource recovery method for organic waste, gaining attention due to carbon reduction. Disposing of anaerobic digestion effluent (ADE) is crucial for developing anaerobic digestion, but conventional wastewater treatment fails to effectively recover nutrients contained in the ADE. In the present study, the ADE without solid-liquid separation was mixed with sewage sludge and Chinese medicine residue for the composting, where the ADE could be recovered at high temperature through humification. Besides, the nitrogen balance, humification process, and microbial dynamics during the composting process were studied. The results showed that the group supplemented with ADE could increase the nitrogen retention efficiency by 2.21 % compared to the control group. High ammonia nitrogen content and salinity did not negatively affect the maturity and phytotoxicity of compost products and even increase the humification degree of compost products. Moreover, additional ADE may not alter microbial community structure, which could contribute to microbial succession. This is the first time to investigate the substance transformation and shift in microbial community structure while applying composting process for ADE treatment, in which the anaerobic-aerobic collaborative disposal process provides an alternative solution for the recovery of ADE.

Tailoring the topology of ZIF-67 metal-organic frameworks (MOFs) adsorbents to capture humic acids

Chlorination is a versatile technique to combat water-borne pathogens. Over the last years, there has been continued research interest to abate the formation of chlorinated disinfection by-products (DBPs). To prevent hazardous DBPs in drinking water, it is decided to diminish organic precursors, among which humic acids (HA) resulting from the decomposition and transformation of biomass. Metal-organic frameworks (MOFs) such as zeolitic imidazolate frameworks (ZIFs) have recently received tremendous attention in water purification. Herein, customized ZIF-67 MOFs possessing various physicochemical properties were prepared by changing the cobalt source. The HA removal by ZIF-67-Cl, ZIF-67-OAc, ZIF-67-NO3, and ZIF-67-SO4 were 85.6%, 68.9%, 86.1%, and 87.4%, respectively, evidently affected by the specific surface area. HA uptake by ZIF-67-SO4 indicated a removal efficiency beyond 90% in 4  90% after 60 min mixing the solution with 0.3 g L-1 ZIF-67-SO4. Notably, an acceptable removal performance (∼72.3%) was obtained even at HA concentrations up to 100 mg L-1. The equilibrium data fitted well with the isotherm models in the order of Langmuir> Hill > BET> Khan > Redlich-Peterson> Jovanovic> Freundlich > and Temkin. The maximum adsorption capacity qm for HA uptake by ZIF-67-SO4 was 175.89 mg g-1, well above the majority of adsorbents. The pseudo-first-order model described the rate of HA adsorption by time. In conclusion, ZIF-67-SO4 presented promising adsorptive properties against HA. Further studies would be needed to minimize cobalt leaching from the ZIF-67-SO4 structure and improve its reusability safely, to ensure its effectiveness and the economy of adsorption system.

Microalgae-based constructed wetland system enhances nitrogen removal and reduce carbon emissions: Performance and mechanisms

Combination of constructed wetlands (CWs) and microalgae-based technologies has been proved as effective wastewater treatment option; however, little attention was paid to investigate the optimal combination ways. This study showed that the integrated system (IS) connecting microalgal pond with CWs exhibited improved pollutant-removal efficiencies and preferred carbon reduction effects compared to other alternatives such as coupled system or independent CWs. Microbial analysis demonstrated that core microorganisms (e.g., Acinetobacter and Thermomonas) of the IS were mostly associated with carbon, nitrogen, and energy metabolism. Based on co-occurrence networks, microbial quantity with denitrification function in the IS accounted for 71.01 % of the microorganism related to nitrogen metabolism, which was higher than that of 48.84 % in the independent CWs, indicating that the presence of microalgae in IS played important role in promoting biological denitrification. These findings provide insights into the microbial mechanism and highlights the complementary effects between microalgae and CWs.

Novel Co3O4@TiO2@CdS@Au double-shelled nanocage for high-efficient photocatalysis removal of U(VI): Roles of spatial charges separation and photothermal effect

Effective spatial separation and utilization of photogenerated charges are critical for photocatalysis process. Herein, novel Co₃O₄ @TiO₂ @CdS@Au double-shelled nanocage (CTCA) with spatially separated redox centers was synthesized by loading Co₃O₄ and Au NP cocatalysts on the inner and outer surfaces of Z-scheme heterojunction (TiO₂ @CdS). The reduction rate constant of U(VI) by CTCA reached 0.218 min^-1 under simulated sunlight irradiation, which was 6.6, 3.2 and 36.3 times than that of monolayer CTCA (0.033 min^-1), CTC (0.068 min^-1) and CT (0.006 min^-1). The full-spectrum light-assisted photothermal catalytic performance can enable CTCA to remove 98.8% of U(VI) and degrade nearly 90% of five organic pollutants simultaneously. Detailed characterizations and theory calculations revealed that the photogenerated holes and electrons in CTCA flow inward and outward. More importantly, Co₃O₄ acts as a "nano heater" to generate the photothermal effect for further enhancing the charge transfer and accelerating the surface reaction kinetics. Meanwhile, the photogenerated electrons and superoxide radicals play a dominant role in reducing the adsorbed U(VI) to insoluble (UO₂)O₂·2H₂O(s). This work provides valuable input toward a novel double-shelled hollow nanocage reactor with excellent photothermal catalysis ability for efficient recovery U(VI) from uranium mine wastewater to address environmental contamination issues.

Novel nitrogen removal process in marine aquaculture wastewater treatment using Enteromorpha ferment liquid as carbon

The process performance of partial denitrification of a novel anaerobic fermentation integrated fixed-film activated sludge (IFAS-AFPD) of Enteromorpha was studied. The response surface method was used to determine the optimal reaction conditions, and the operation experiment was carried out under the optimal conditions. The results showed that the nitrogen removal effect was the best when the salinity was 12.2 g•L^-1, the Carbon-Nitrogen ratio (C/N) was 4, the pH was 8.5, and the Nitrite Accumulation Rate, Nitrate Removal Rate, Chemical Oxygen Demand Utilization Rate could reach 77%, 89% and 51%. Experimental results have shown that the NAR of the Enteromorpha ferment liquid system could be maintained at about 74%, which was noteworthy higher than that of the sodium acetate (CH₃COONa) system at 42%; Microbial community analysis showed that Enteromorpha ferment liquid was more beneficial to the growth of Bacteroidetes than CH₃COONa.

Evaluation of Efficiently Removing Secondary Effluent Organic Matters (EfOM) by Al-Based Coagulant for Wastewater Recycling: A Case Study with an Industrial-Scale Food-Processing Wastewater Treatment Plant

The reuse of wastewater has been identified as an important initiative for the sustainable development of the environment; thus, the removal of secondary effluent organic matter (EfOM) to ensure the safety of reused wastewater is the key step and a subject of extensive research. In this study, Al₂(SO₄)₃ and anionic polyacrylamide were selected as coagulant and flocculant, respectively, for the treatment of secondary effluent from a food-processing industry wastewater treatment plant to meet the standard regulatory specifications for water reuse. In this process, the removal efficiencies of chemical oxygen demand (COD), components with UV₂₅₄, and specific ultraviolet absorbance (SUVA) were 44.61%, 25.13%, and 9.13%, respectively, with an associated reduction in chroma and turbidity. The fluorescence intensities (Fmax) of two humic-like components were reduced during coagulation, and microbial humic-like components of EfOM had a better removal efficiency because of a higher Log Km value of 4.12. Fourier transform infrared spectroscopy showed that Al₂(SO₄)₃ could remove the protein fraction of the soluble microbial products (SMP) of EfOM by forming a loose SMP protein complex with enhanced hydrophobicity. Furthermore, flocculation reduced the aromaticity of secondary effluent. The cost of the proposed secondary effluent treatment was 0.034 CNY t^-1 %COD^-1. These results demonstrate that the process is efficient and economically viable for EfOM removal to realize food-processing wastewater reuse.

Humic Substances as a Versatile Intermediary

Humic substances are organic ubiquitous components arising in the process of chemical and microbiological oxidation, generally called humification, the second largest process of the carbon cycle. The beneficial properties of these various substances can be observed in many fields of life and health, whether it is the impact on the human organism, as prophylactic as well as the therapeutic effects; animal physiology and welfare, which is widely used in livestock farming; or the impact of humic substances on the environment and ecosystem in the context of renewal, fertilization and detoxification. Since animal health, human health and environmental health are interconnected and mutually influencing, this work brings insight into the excellence of the use of humic substances as a versatile mediator contributing to the promotion of One Health.

Amphiphilic Grafted Polymers Based on Citric Acid and Aniline Used to Enhance the Antifouling and Permeability Properties of PES Membranes

Water treatment technology based on ultrafiltration (UF) faces the problem of severe membrane fouling due to its inherent hydrophobicity. The use of amphiphilic polymers that possess both hydrophobic and hydrophilic chain segments can be advantageous for the hydrophilic modification of UF membranes due to their excellent combination in the membrane matrix. In the present study, we examined a novel amphiphilic CA-g-AN material, constructed by grafting citric acid (CA) to aniline (AN), as a modified material to improve the hydrophilicity of a PES membrane. This material was more compatible with the polymer membrane matrix than a pure hydrophilic modified material. The polyethersulfone (PES) membranes modified by amphiphilic CA-g-AN demonstrated a higher water flux (290.13 L·m^-2·h^-1), which was more than eight times higher than that of the pure PES membrane. Furthermore, the flux recovery ratio (FRR) of the modified membrane could reach 83.24% and the value of the water contact angle (WCA) was 76.43°, demonstrating the enhanced hydrophilicity and antifouling ability of the modified membranes. With this study, we aimed to develop a new amphiphilic polymer to improve the antifouling property and permeability of polymer-based UF membranes to remove organic pollutants from water.