Production Wastewater Research Articles

Distribution of Microorganisms and Antibiotic Resistance Genes in Production Wastewater During Pumped Storage Power Station Construction

The construction period of pumped storage power stations (PSPS) generates amounts of production wastewater, which may contain pathogenic bacteria and antibiotic resistance genes (ARGs) in these bacteria, potentially posing environmental and health risks. This study used the metagenome approach to analyze the distribution of microorganisms, ARGs and their correlation with water quality indicators in wastewater collected from two typical PSPSs. Coagulation system wastewater exhibits strong alkalinity (11.88), and aggregate system wastewater has high suspended solids (SS, 8 × 104 mg/L), resulting in lower richness and diversity of bacterial communities. Serpentinimonas, a kind of alkaliphilic bacteria, had the highest relative abundance (48.58–99.7%). The ARG subtypes obtained conferred wastewater resistance to tetracycline, macrolide, fluoroquinolone and so on, but wastewater treatment has limited removal effect on ARGs. The results indicate that resistant bacteria and resistance genes can still be present and distributed under highly alkaline conditions, and the removal efficiency of ARGs by wastewater treatment in PSPS is limited. Attention should be given to the environmental and health risks posed by production wastewater, thereby providing a theoretical basis for the sustainable development of the PSPS industry.

In Situ Imaging of Cellular Inflammatory Response to Antibiotic Exposure with a DNAzyme Nanorobot.

Antibiotic-induced inflammation involves the release of myeloperoxidase (MPO), an enzyme whose expression in tissues is associated with the inflammatory pathway. However, existing methods for detecting MPO in cells are limited. In this study, a DNAzyme nanorobot was developed using a scaffold of gold nanoparticles (AuNPs) decorated with functional DNAzyme strands and their fluorophore-labeled substrate strands. The DNAzyme remains inactive due to a self-assembled hairpin structure, with a phosphorothioate (PT) modification inserted into the stem domain. When MPO is present, it triggers a halogenation process that generates hypochlorous acid (HClO). HClO specifically catalyzes the cleavage of the PT-site, releasing free DNAzyme strands to cleave their substrates and generating an increasing fluorescent signal. The detection limit for MPO and its primary product, HClO, were determined to be 0.038 μg/mL and 0.013 μM, respectively. The DNAzyme nanorobot can be readily introduced into cells and function autonomously to differentiate increased MPO/HClO levels caused by antibiotics. This approach was applied to image RAW264.7 cells exposed to four prevalent antibiotics found in the environment (phorbol 12-myristate 13-acetate, erythromycin, penicillin, and tetracycline) as well as antibiotic production wastewater. This nanorobot offers novel strategies for monitoring inflammation to evaluate the health impacts of antibiotic exposure.

An Integrated Pilot-Scale Upflow Anaerobic Sludge Blanket (UASB) and Aerotank System for the Treatment of Rice Paper Production Wastewater: A Case Study from Phu Hoa Dong, Ho Chi Minh City, Vietnam

An Integrated Pilot-Scale Upflow Anaerobic Sludge Blanket (UASB) and Aerotank System for the Treatment of Rice Paper Production Wastewater: A Case Study from Phu Hoa Dong, Ho Chi Minh City, Vietnam

Simultaneous degradation of pharmaceuticals and personal care products in hospital wastewater using ozone under ultraviolet irradiation

The discharge of Pharmaceuticals and personal care products (PPCPs) from industries and hospitals are responsible for the contamination of water body with slow or non-degradable toxic compounds. The removal of these contaminants required advanced treatment process because of unable to treat by conventional wastewater treatment process. In this study, the degradation of PPCP compounds, including caffeine (CAF), atenolol (ATL), carbamazepine (CBZ), sulfamethoxazole (SMX), trimethoprim (TMP), and acetaminophen (ACT) was evaluated under exposure to 1.0 and 1.5 mg/L dissolved ozone (O3), both with and without ultraviolet (UV) irradiation (254 nm). Using liquid chromatography with tandem mass spectrometry, we determined that the removal efficiency for the targeted contaminants exceeded 95 % within just 20 min of exposure to both 1.0 and 1.5 mg/L O3. However, when treated with UV light alone, the removal efficiency was limited at 3 %–11 %. A combination treatment involving dissolved 1.5 mg/L O3 and UV light led to over 97 % removal within 7 min. This outcome was attributed to hydroxylation reactions, aromatic ring opening, oxidation, and mineralization facilitated by the HO and peroxide generated through the photolysis of O3. The degradation rate of PPCP compounds followed pseudo-first-order kinetics and showed a decrease in the presence of humic acid and hospital wastewater further decreased it. Moreover, O3/UV treatment generated lower-weight degradation products. The toxicity analysis revealed that these transformation products exhibited environmental benignity and minimal health risks which O3/UV treatment potentially minimizes the presence of harmful byproducts. These findings provide a foundation for developing combined hybrid systems for PPCP containing wastewater, containing membrane filtration with ozonation system.

Microplastics in wastewater plants: A review of sources, characteristics, distribution and removal technologies

Microplastics (MPs) are widespread in everyday life, and since wastewater treatment plants (WWTPs) serve as an important route for MPs to enter natural water bodies, a thorough understanding of the distribution and removal of MPs in wastewater treatment plants is of great importance. This article provides a comprehensive overview of the measured distribution of MPs and the current status of their removal in wastewater treatment plants. The main sources of MPs in wastewater treatment plants are personal care products in domestic wastewater, textile clothing and industrial wastewater made from plastics, textile factories and the friction of road tires. The MPs that entered the sewage treatment plant were predominantly in the form of fibers, fragments, granular MPs and other types of MPs. The size of MPs is divided into three categories: <0.5 mm, 0.5–1 mm and 1–5 mm. At all treatment stages in wastewater plants, 56.8–88.4 % of MPs are removed in primary treatment, but the primary sedimentation and degreasing stages remove most MPs. The efficiency of the activated sludge process for secondary treatment is inconsistent and is generally between 42.1 and 99.2 %. The coagulation, filtration and disinfection stages of tertiary treatment all have some MPs removal capacity. In addition, novel removal technologies are also described, such as modified filtration technology, membrane separation technology, electroflocculation, sol-gel and photocatalysis. These novel removal technologies can further limit the entry of microplastics into natural water bodies through sewage treatment plants and improved sewage treatment processes help reduce the risk of MPs entering the natural environment through sewage treatment plants. This article will provide reference for the distribution and removal of microplastics in various levels of WWTPs.

Strain selection and adaptation of a fungal-yeast-microalgae consortium for sustainable bioethanol production and wastewater treatment from livestock wastewater

This study explores the potential of strain selection and adaptation for developing a fungi-yeast-microalgae consortium capable of integrated bioethanol production and livestock wastewater treatment. We employed a multi-stage approach involving isolation and strain selection/adaptation of these consortiums. The study started with screening some isolated fungi to grow on the cellulosic biomass of the livestock wastewater (saccharification) followed by a fermentation process using yeast for bioethanol production. The results revealed that Penicillium chrysogenum (Cla) and Saccharomyces cerevisiae (Sc) produced a remarkable 99.32 ppm of bioethanol and a concentration of glucose measuring 0.56 mg ml− 1. Following the impact of fungi and yeast, we diluted the livestock wastewater using distilled water and subsequently inoculated Nile River microalgae into the wastewater. The findings demonstrated that Chlorella vulgaris emerged as the dominant species in the microalgal community. Particularly, the growth rate reached its peak at a 5% organic load (0.105385), indicating that this concentration provided the most favorable conditions for the flourishing of microalgae. The results demonstrated the effectiveness of the microalgal treatment in removing the remaining nutrients and organic load, achieving a 92.5% reduction in ammonia, a 94.1% reduction in nitrate, and complete removal of phosphate (100%). The algal treatment also showed remarkable reductions in COD (96.5%) and BOD (96.1%). These findings underscore the potential of fungi, yeast, and Nile River microalgae in the growth and impact on livestock wastewater, with the additional benefit of bioethanol production.Graphical abstract

Characterization, fractionation and untapped potential of phosphate-amended sewage sludge biochar in soil-plant systems

Sewage sludge, a byproduct of wastewater treatment, poses serious environmental and health risks due to its content of organic contaminants, heavy metals, and pathogenic microorganisms. With the growing global production of municipal wastewater, finding effective methods for managing and disposing of sewage sludge has become increasingly urgent. Traditional methods such as land disposal, dumping, and incineration have limitations and environmental drawbacks. However, recent advancements have shown promise in the valorization of sewage sludge, particularly through pyrolysis, which converts it into biochar for use in soil amendment and pollutant mitigation. This study aims to characterize and fractionate phosphate-amended sewage sludge biochar produced at 300 °C, 400 °C, and 500 °C, and to evaluate its potential use in soil-plant systems. It examines nutrient bioavailability in soil after the addition of this biochar and its effects on plant growth. The pyrolysis process resulted in biochar with high alkalinity (7.2–11.1), ash content ranging from 56.9% to 87.3%, and significant phosphorus retention, with phosphorus concentrations increasing with pyrolysis temperature (5.35%–9.38%). Phosphorus fractionation showed a shift toward more stable fractions particularly at 500 °C. Soil incubation experiments indicated increased phosphorus availability with HCl-extractable P showing a high extraction efficiency of up to 94.95%. In plant growth experiments, the amended biochar significantly enhanced growth, with corn showing an increase of up to 28.8% and wheat showing an increase of up to 86% compared to the control in the first four weeks after emergence. These findings indicate that phosphate-amended sewage sludge biochar enhances nutrient availability and supports plant growth, providing a sustainable solution for sewage sludge management, contributing to soil improvement and carbon sequestration, thereby addressing global environmental challenges.

MIL-125-PDI/ZnIn2S4 Inorganic-Organic S-Scheme Heterojunction With Hierarchical Hollow Nanodisc Structure for Efficient Hydrogen Evolution from Antibiotic Wastewater Remediation.

Efficient photocatalytic production of H2 from wastewater is expected to address environmental pollution and energy crises effectively. However, the rapid recombination of photoinduced carriers results in low photoconversion efficiency. At present, inorganic-organic S-scheme heterojunction have become a prominent and promising technology. In this study, an organic ligand modified MIL-125-PDI/ZnIn2S4 (ZIS) inorganic-organic S-scheme heterojunction catalyst is designed. ZIS nanosheets are grown on the disc-shaped MIL-125-PDI surface to form a distinctive hollow nanodiscs with hierarchical structure, giving the material an abundance of surface active sites, an optimized electronic structure, and a spatially separated redox surface. Consequently, the optimal 100MIL-125-PDI250/ZIS exhibited high photocatalytic HER of 508.99 µmol g-1 h-1 in Tetracycline hydrochloride (TC-HCl) solution. Meanwhile, the catalyst achieved complete TC-HCl removal and mineralization rate of 66.62% in 4h. Experimental and theoretical calculations corroborate that the staggered band alignment and work function difference between MIL-125-PDI and ZIS induce the formation of a built-in electric field, thus regulating the charge transfer routes and consequently enhancing charge separation efficiency. The possible photocatalytic mechanism is analyzed using liquid chromatography-mass spectrometry (LC-MS), and the toxicities of the degradation products are also evaluated. This work presents a green dual-function strategy for H2 production and antibiotic wastewater recycling.

Per- and poly-fluoroalkyl substances in aquatic ecosystems and wastewater treatment works in Africa: Occurrence, ecological implications, and future perspectives

The increasing levels of industrialization and urbanization have led to the generation of significant amounts of wastewater and waste products, often containing chemicals like per- and poly-fluoroalkyl substances (PFASs) commonly found in consumer products. PFASs are known for their persistence, ubiquity, and ecotoxicological impacts, raising concerns about potential harm to ecosystems. This paper reports the occurrence and evaluates the ecological risks of PFASs in aquatic ecosystems and wastewater treatment works (WWTWs) across Africa. We reviewed 32 papers published in the period 2009–2024 and identified a total of 35 PFAS compounds in surface waters, wastewater, sediments, fish, crocodiles, and invertebrates. Much of the reported studies came from South Africa, followed by Kenya and Nigeria. PFAS concentrations in Africa were <0.7–390.0 ng L−1 in surface waters, 0.05–772 ng g−1 dw in sediments, and <0.2–832 ng L−1 in wastewater, while the highest levels in fish and invertebrates were 460.7 and 35.5 ng g−1 ww, respectively. The PFAS levels were in the same range of data as those reported globally. However, the high concentrations of PFASs in sediments and wastewater suggest areas of point contamination and a growing risk to aquatic ecosystems from effluent discharges. Calculated risk quotients suggested that, in Africa, organisms in river systems face greater risks due to exposure to PFASs compared to those in lakes, while marine organisms might face higher risks compared to freshwater organisms. Future studies should focus on PFAS contamination sources, especially WWTWs, as emerging sources of PFASs in aquatic systems.

Direct Electrolysis of Municipal Reclaimed Water for Efficient Hydrogen Production Using a Bifunctional Non-Noble-Metal Catalyst.

Water electrolysis for green H2 production traditionally requires a stable supply of renewable electricity and pure water. However, spatial separation of renewables and water resources as well as water scarcity per capita in China necessitate unconventional water resources for electrolysis. Reclaimed water produced from municipal wastewater treatment plants is widely distributed with quality improved significantly in recent years, which may be a promising alternative to feedstock. However, there are few reports on the direct use of this wastewater for H2 production. Here, we present a direct electrolysis of reclaimed water for decentralized H2 production by developing a highly efficient and stable bifunctional 3D-dandelion-like (DL) vanadium(V)-doped CoP catalyst grown in situ on Ni foam (NF) in an alkaline electrolyzer. The V-CoP-DL/NF electrode decreases 6.5 and 25% overpotentials of the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively, compared to noble-metal Pt (HER) and IrO2 (OER) catalysts, and exhibits exceptional durability, as a voltage required for overall reclaimed water splitting only increases by 80 mV (1.81-1.89 V) after 90 days of operation at a current density of 10 mA cm-2. The maximum stable current can reach 1000 mA cm-2. The impacts of potential pollutants in reclaimed water on the performance of electrolysis and the behavior of major wastewater ions in alkaline electrolyte were investigated. The observed exceptional performance is attributed to the catalyst's unique nanostructure, which enhances charge transfer and reactant/electrolyte diffusion. The in situ growth strategy further enhances the conductivity and stability of the catalyst. This work underscores the feasibility of utilizing reclaimed water instead of pure water as the feedstock for sustainable hydrogen production.

Al-etching-induced defect engineering in NiAl LDHs for promoting multifunctional electrocatalytic oxidations: Water oxidation and urea oxidation

Electrocatalytic water splitting is a promising avenue to produce green hydrogen for future sustainable development. Developing multifunctional catalysts with high-performance toward urea oxidation reaction (UOR) and oxygen evolution reaction (OER) offers a unique approach for simultaneously achieving the degradation of urea-containing wastewater and energy-saving hydrogen production. Ni-based materials are a kind of promising materials for electrocatalysis, since its abundant reserve and tolerance. However, low intrinsic activity and catalytic efficiency hinder its wide application. Here, a defect engineering strategy is developed to create vacancies on NiAl layer double hydroxides (LDHs) catalysts by selectively etching Al ions in strong alkaline solution. The obtained NiAl LDHs with rich defects (D-NiAl LDHs) exhibit good OER performance with overpotential of 264 mV to achieve a current density of 10 mA cm−2 and a Tafel slope of 39.8 mV dec−1. In addition, the D-NiAl LDHs catalysts also show excellent UOR activity using a potential of 1.328 V vs. RHE @ 10 mA cm−2 in alkaline solution. In comparation to NiAl LDHs, the enhanced performance of D-NiAl LDHs toward oxidation of small-molecule OH− and urea could be attributed to electronic regulation of defects and a larger electrochemical surface area. Partially replacing the OER with the UOR, the driving voltage of overall water splitting reduces effectively from 1.856 V to 1.688 V at a current of 100 mA cm−2.

Valorization of Strawberry Juice Production Wastewater: Possibilities for Polyphenols Recovery and Plant Biostimulant Production.

Fruit juice production is one of the most important branches of the food and beverage industry, considering both the market size and demand. It is also one of the largest generators of industrial wastewater, considering the large consumption of fresh water during fruit processing. Hence, the appropriate treatment strategies are of the utmost importance to minimize the environmental footprint of food industry effluents. This study aimed to investigate the valorization routes for strawberry juice production wastewater (SJPW), both in terms of nutrient recovery and a circular approach to its utilization as a medium for plant biostimulant production. The results show a low antioxidant capacity and low content of polyphenols in SJPW; however, promising results were obtained for the in vitro seed germination and tomato growth promotion when investigating a biostimulant based on Bacillus sp. BioSol021, which was cultivated using SJPW in a lab-scale bioreactor, with root and shoot length improvements of approximately 30% and 25%, respectively, compared to the control samples. The plant growth promotion (PGP) traits indicated the ability of IAA production, in a concentration of 8.55 ± 0.05 mg/L, and the enzymatic activity was evaluated as through the enzymatic activity index (EAI), achieving the following: 2.26 ± 0.04 for cellulolytic activity, 2.49 ± 0.08 for hemicellulolytic activity, 2.91 ± 0.16 for pectinolytic activity, and 1.05 ± 0.00 for proteolytic activity. This study opens a new chapter of possibilities for the development of techno-economically viable circular bioprocess solutions aimed at obtaining value-added microbial products for sustainable agriculture based on the valorization of food industry effluents thus contributing to more sustainable food production at both the agricultural and industrial levels.

Life cycle assessment (LCA) and economic analysis of two-stage anaerobic process of co-digesting palm oil mill effluent (POME) with concentrated latex wastewater (CLW) for biogas production

This study outlines the results of a process-based life cycle assessment (LCA) of the environmental performance of biogas production from co-digestion of palm oil mill effluent (POME) and concentrated latex wastewater (CLW) in the two-stage anaerobic digestion (AD) process. Biogas is utilized global across several sectors, including electricity generation, heating, and transportation. The Open LCA 2.0.2 software was used to evaluate the LCA at the midpoint level by using 18 different impact categories. This study reveals the three main contributions of the AD process, which were global warming (8.65 × 102 kg CO2eq), water consumption (5.32 m3), and land use change (3.39 × 102 m2 a crop eq), this result corresponded with the previous study in Malaysia that examined biogas production from the AD of POME In addition, alternative scenarios, in which a single substrate, have been established to quantify the impacts of potential improvements of biogas production to compare with base scenario of co-digestion. The results show that the environmental impacts of the base scenario released were lower than those of the single POME substrate of alternative scenario 1 in most impact categories. Furthermore, economic analysis is a crucial factor in the practical implementation of the AD process. Linking LCA with economic analysis offers a comprehensive perspective on sustainability, balancing environmental impacts with financial performance to optimize the potential of the AD co-digestion process. This is the first study to apply LCA and economic analysis to this specific co-digestion process in a two-stage AD system. The economic analysis of the two-stage AD of co-digesting POME and CLW was 1200 m3/d production of wastewater (70 % of POME and 30 % of CLW) based on the factories' data. The result indicates net present value, internal rate of return, and payback period of 515,813.94 USD, 9.13 %, and 8.87 years, respectively. This work proposed the potential approach for implementing the two-stage AD co-digestion of POME and CLW while concurrently producing valuable bioenergy carriers.

Analysis of the effectiveness of organic compounds from the amine group in precipitating ions from soda production wastewater

Treating wastewater from the soda industry is a complicated and lengthy process, requiring a great deal of labor and financial resources. No method has yet been developed to eliminate the environmental damage caused by the soda industry entirely. The work focused on the removal of chloride, sulfate, calcium, and magnesium from soda production wastewater by precipitation using organic solvents such as isopropylamine (IPA), diisopropylamine (DIIPA), propylamine (PA) and ethylamine (EA) in various proportions. Statistical modeling through Bayesian beta regression was used to select the amine most effectively removing the tested ions in precipitate form. The effect of precipitating agent dosage on the pH and conductivity of the solution was also investigated. Samples of wastewater obtained from the soda industry were characterized by high values of pH (up to 11.9), specific electrolytic conductivity (up to 128 mS cm-1), and high concentrations of sodium (up to 13 g L-1), chloride (up to 60 g L-1) and calcium (up to 24 g L-1) ions. Solvent-based precipitation showed that organic solvents are effective in precipitating salts from wastewater from the soda industry. Sulfate and chloride removal efficiencies of 85.1 and 34%, respectively, were observed. Statistical analysis showed that isopropylamine was the most effective amine for removal.

Evaluating the economic influence of water sources on green hydrogen production: A cost analysis approach

The production of green hydrogen requires significant water usage, making the economic evaluation of different water sources crucial for optimizing the Levelized Cost of Hydrogen (LCOH). This study examines the economic impact of using seawater, groundwater, grid water, industrial wastewater, and rainwater for hydrogen production through PEM electrolysis considering the water abstraction, transport, treatment, and storage costs across various plant sizes (1 MW, 10 MW, 20 MW, 50 MW, and 100 MW) were assessed and a sensitivity analysis on electricity prices was conducted. Findings reveal that while water-related costs are minimal (<2% of LCOH), transport distance significantly impacts LCOH, sometimes exceeding 10%. Future studies should integrate life cycle analysis and sustainability criteria beyond economic factors, considering social, ecological, and technical dimensions.

Molecular insights into the enhanced growth of cyanobacteria by adaptive laboratory evolution in wastewater environments

The expansion of population leads to an increase in nutrient-rich wastewater, posing a threat to the ecosystem. The cultivation of economically beneficial cyanobacteria consumes amounts of freshwater, exacerbating the depletion of freshwater resources. This study investigates the potential of utilizing adaptive laboratory evolution (ALE) to enhance the growth performance of Synechocystis sp. PCC 6803, a model cyanobacterium, in wastewater. After 374 days of ALE, a strain designated as WW was successfully evolved. When cultivated in wastewater, WW exhibited a specific growth rate of 0.317 per day and achieved a dry weight of 0.693 g/L by the 13th day, outperforming the wild type. WW achieved removal efficiencies of 35.55 % for total nitrogen and 60.95 % for total phosphorus in the wastewater. RNA sequencing and photosynthetic measurements revealed that enhanced photosynthetic capacity in the WW contributes to its superior growth performance. The lipid content in WW was 16.19 %, with a notable increase in the proportion of polyunsaturated fatty acids. The shift in fatty acid composition has a consequential impact on biodiesel index, including oxidation stability and saponification number. This study not only demonstrates the effectiveness of ALE in enhancing the growth of cyanobacteria in wastewater for biofuel production, but also offers significant insights into the molecular mechanisms that drive this improved performance.

Environmental Valuation of Wastewater Used in Agricultural Production

In recent years, problems related to the adequacy of existing water resources have arisen due to issues such as population growth, rapid urbanization, industrialization, and climate change. Especially in agricultural production where water is used the most, the use of wastewater has become widespread as a solution to this problem. Considering that wastewater may harm the environment due to the substances it contains, it is aimed to make an environmental valuation in this study. In this context, by using the travel cost method used in the valuation of goods without a market, a different approach was brought to this method, as agricultural production is concerned, and an evaluation was made based on producer surplus. In the study, by comparing the agricultural productions with wastewater and well water, 2 hypotheses have been developed about the environmental valuation of wastewater; First, if the producer surplus of agricultural production with wastewater is lower than that of production with well water, there is environmental pollution, and its value is the difference between the two rents. The second hypothesis is that if the producer's surplus with wastewater is high, positive externality will occur as a hypothesis against the negative effects of environmental pollution. By conducting a survey with 125 producers in the research area, the data of 314 parcels in total were included in the analysis, and the producer surplus was calculated by creating the supply function with the regression analysis. As a result of the research, the producer surplus (584.40$) obtained from the agricultural production made by irrigating with wastewater was found to be higher than the producer surplus (553.44$) of the production made by irrigating with well water. In this case, it was concluded that the wastewater irrigated did not affect the environmental pollution, but the positive externality. Although the use of wastewater in agricultural production has made a positive contribution to the economy, it will be beneficial to use it after the necessary treatment processes, considering its harmful effects on human health.

Winter Season Outdoor Cultivation of an Autochthonous Chlorella-Strain in a Pilot-Scale Prototype for Urban Wastewater Treatment

The global population increase during the last century has significantly amplified freshwater demand, leading to higher wastewater (WW) production. European regulations necessitate treating WW before environmental. Microalgae have gained attention for wastewater treatment (WWT) due to their efficiency in remediating nutrients and pollutants, alongside producing valuable biomass. This study investigates the phycoremediation potential of a Chlorella-like strain isolated from urban WW in a 600L-scale system under winter conditions. Experiments in December 2021 and February 2022 tested the strain’s adaptability to varying environmental conditions, particularly temperatures (min-max temperature range: from −3.69 to 10.61 °C in December and −3.96 to 17.61 °C in February), and its ability to meet legal discharge limits. In December, low temperatures algal growth. Nitrates showed an RE of about 92%, while ammonia slightly decreased (RE, about 32%), and phosphorous remained unchanged. In February, mild temperatures increased algal density (33.3 × 106 cell mL−1) and, at the end of experiment, all nutrients were below legal limits with very high RE % (NH4+, 91.43; PO43− 97.32). Both trials showed an E. coli RE, % = 99%. The study highlights the potential of microalgae for WWT and the importance of considering seasonal variations when implementing these systems.

Advancing Aquaculture Sustainability: A Comprehensive Review of Biofloc Technology Trends, Innovative Research Approaches, and Future Prospects

ABSTRACTBiofloc technology (BFT), initially adapted for shrimp farming in the 1970s, represents a sophisticated ecosystem of microorganisms designed to enhance aquaculture productivity and sustainability. Despite its established history, research into BFT is surprisingly still at an early stage globally. This review conducted a bibliometric analysis of 612 articles from major aquaculture journals spanning 2008–2023 to systematically explore the development, trends, and focal points of BFT research. The analysis revealed that the bulk of significant contributions originates from Brazil and China, and highlighting areas of interest can be categorized into four hotspots, such as (1) efficient nitrogen transformation, (2) biofloc microbiology, (3) biofloc's immunostimulant properties, and (4) the evaluation of research methodologies. At the end, the microecology concept was introduced, and the cross‐discipline methods were promoted in the aquaculture field. Notably, much of the BFT research is still at an exploratory phase, with numerous functional bacteria unidentified and optimization strategies for BFT underdeveloped. These gaps present opportunities for enhancing aquaculture through improvements in wastewater management, product quality, safety, and yield. Furthermore, the review notes a growing trend in applying microbiome research and microecological analysis in aquaculture, with high‐throughput sequencing data increasingly used to understand microbial interactions and nitrogen transformation within bioflocs. This direction promises to unlock further insights into the complex microbial ecosystems of bioflocs and their applications in sustainable aquaculture.

Separation and extraction of NH4Br and (K,NH4)2SO4 from 1-Bromooctane production wastewater by crystallization method

This work provides a method for the separation and extraction of bromine salts from bromine-containing wastewater by crystallization. Wastewater from the production of 1-Bromooctane is rich in potassium and bromine salts. This will allow for the recycling of chemical resources in this aqueous salt system. Based on the need for the process design of the new method, the solubility phase equilibrium of the quaternary K+,NH4+//SO42-,Br-–H2O system at 298.15 K and 323.15 K was investigated in this paper by using the isothermal dissolution equilibrium method, and the dry basis phase diagrams were plotted using the experimental data. And the equilibrium solid phase composition was determined by X-ray diffraction. At 298.15 K, the dry phase diagram of the quaternary system K+,NH4+//SO42-,Br-–H2O consists of three invariant points and five crystalline regions (K2SO4, (NH4)2SO4, (K,NH4)2SO4, (K,NH4)Br, (NH4,K)Br). At 323.15 K, there is one invariant point in the phase diagram of this quaternary system and three crystalline regions((K,NH4)2SO4, (K,NH4)Br, (NH4,K)Br). The (K,NH4)Br crystallization zone grows while the (NH4,K)Br crystallization zone decreases with increasing temperature, according to comparisons of the dry basis phase diagrams of this quaternary system at different temperatures. Crystallization zones of solid solution (K,NH4)2SO4 replaced the K2SO4 and (NH4)2SO4 single salt crystallization zones at the same time. The Pitzer model was used to calculate the solubility of this quaternary system at 298.15 K. The results showed that the experimental values were in good agreement with the calculated values. Based on the theoretical analysis of the dry phase diagram of the quaternary system K+,NH4+//SO42-,Br-–H2O, a process route for salt extraction using bromine-containing wastewater generated from the production of 1-Bromooctane was proposed and designed. The new process was experimentally verified to be technically feasible to obtain NH4Br with 99.01 % purity and (K,NH4)2SO4. The process has significant advantages, such as production safety, low input costs and no three-waste emissions.