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Copyright of Tecnología y Ciencias del Agua is the property of Instituto Mexicano de Tecnologia del Agua (IMTA) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study evaluated the influence of organic matter (OM) constituents on the potential for recovery of P from wastewaters when FeCl3 treatment is employed for P removal. The presence of OM constituents did not influence P release from Fe‐P sludges when alkaline and ascorbic acid treatments were employed. However, the overall recovery of P from wastewater was impacted by the presence of selected OM constituents through the reduction of P uptake during coagulation. The presence of protein and humic matter showed remarkably low P removal values (3.0 ± 0.4% and 23 ± 1% respectively) when compared to an inorganic control recipe (62 ± 2%). Elevated soluble Fe (SFe) residuals in the presence of proteins (87 ± 5%) and humics (51 ± 1%) indicated interactions between Fe(III) cations and negatively charged functional groups like hydroxyl, carboxyl, and phenolic groups available in these organics. Significant negative correlations between P removal and residual SFe were observed suggesting Fe solubilization by OM constituents was the mechanism responsible for reduced P removal. The findings of this study identify, for the first time, the impact of OM constituents on overall P recovery when Fe(III) salts are employed and provide insights into recoveries that can be expected when Fe is added to primary, secondary treated, and industrial wastewaters. Practitioner Points: Low P removal values were observed for protein and humic dominated wastewater recipes.Iron(III) solubilization counted for P removal reduction by proteins and humic acids.There is no effect of OM on P release from Fe‐P sludge at pH 10 and ascorbic acid treatments.OM and agent employed to release P from sludges affected overall recovery of P. [ABSTRACT FROM AUTHOR]

Phosphorus in wastewater from pressed vegetables is a significant contributor to water pollution, emphasizing the importance of its removal and recycling for ecological management. In this study, an improved method of coprecipitation pyrolysis of Mg(OH)2 and FeCl3•6H2O was used to successfully synthesize iron-magnesium biochar composite (FeMg@BC2) from corn cob. Compared with iron-modified biochar (Fe@BC), magnesium-modified biochar (Mg@BC), and iron–magnesium-modified biochar (FeMg@BC1) prepared by traditional coprecipitation methods, the improved iron–magnesium biochar had higher yield, specific surface area, and crystallinity. The study investigated the impact of modified biochar dosage, initial solution pH, and coexisting ions on the adsorption capabilities of modified biochar for phosphate removal. The results demonstrated that the addition of 1.0 g/L FeMg@BC2 was highly effective in removing phosphate from simulated wastewater when the phosphate concentration was 80 mg/L, achieving a removal rate exceeding 95%. Using an adsorption isotherm model, the maximum phosphate adsorption capacities of Fe@BC, Mg@BC, FeMg@BC1, and FeMg@BC2 were estimated to be 40.76, 46.97, 96.78, and 107.97 mg/g, respectively. Particularly, FeMg@BC2 exhibited superior phosphate adsorption capacity, and its adsorption mechanism mainly included electrostatic attraction, surface precipitation, and ligand exchange. The desorption test of phosphorus-loaded modified biochar revealed that the desorption rates of FeMg@BC2 from simulated wastewater and pressed vegetable wastewater using a 0.5M NaOH solution were 92.2% and 84.8%, respectively. After three cycles of adsorption in pressed vegetable wastewater, the phosphorus removal efficiency of FeMg@BC2 at 1.0 g/L remained about 50%. Therefore, the utilization of FeMg@BC2 for phosphorus recovery from pressed vegetable wastewater showed promising potential. [ABSTRACT FROM AUTHOR]

The influent of municipal wastewater treatment plants (WWTPs) in China is generally facing the problem of insufficient carbon sources. Pyrite-based autotrophic denitrification (PAD), which uses pyrite as an electron donor, has good advantages of less acid production, low sulfate generation, and efficient simultaneous nitrogen and phosphorus removal from wastewater. In this study, a novel type of mixotrophic sequencing batch biofilm reactor (SBBR) was constructed by combining PAD with SBBR, and the effect of reflux ratio on the treatment efficiency of pyrite-based SBBR was studied. The research showed that the addition of reflux improved the removal capability of nitrogen and phosphorus, and the optimal reflux ratio for the pyrite-based SBBR was 200% when the removal rates of CODCr , NH4+-N , TN, and PO43−-P reached 71.07%±5.33% , 80.94%±7.23% , 53.94%±3.34% , and 49.68%±11.85% , respectively in the anoxic environment with pH 7–8. The variation of pollutants in the typical operating cycle showed that most of the organic pollutants were removed in the aerobic stage. The analysis of extracellular polymeric substances (EPS) further verified that the addition of reflux was beneficial to the removal of nitrogen and phosphorus. [ABSTRACT FROM AUTHOR]

Copyright of China Brewing is the property of China Brewing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Featured Application: This research underscores the effectiveness of using seashells and ceramic bricks as substrates in vertical flow CW for greywater treatment. The findings are particularly relevant for rural and semi-arid regions, where these low-cost, sustainable systems can enhance water quality. The study also provides valuable insights into optimizing macrophyte age and substrate materials, offering practical solutions for decentralized wastewater treatment in underserved areas. This technology can be particularly beneficial for decentralized wastewater treatment in communities with limited access to advanced infrastructure, offering a practical solution for improving water quality and sustainability in resource-constrained environments. Constructed wetland (CW) systems have been recognized as a sustainable technology for wastewater treatment that can be easily integrated into the local natural environment, offering both low cost and high efficiency. In this study, synthetic greywater was treated using a vertical subsurface flow CW operated in batch mode with 7-day cycles across two phases, operated in parallel: I, non-vegetated, and II, vegetated, with Echinodorus subalatus. The mixed filter bed was composed of seashells, ceramic brick fragments, and sand. No statistically significant differences (p > 0.05) were observed between the non-vegetated and vegetated phases for most parameters. The removal efficiencies of organic matter, anionic surfactants, and total phosphorus in the non-vegetated versus vegetated phases were (91.0 ± 3.8)% versus (94.0 ± 1.1)%; (71.9 ± 14.1)% versus (60.0 ± 9.5)%; and (35.2 ± 4.6)% versus (40.2 ± 15.5)%, respectively. Phosphorus removal exceeded values reported in the literature for both phases, primarily due to the calcium present in the seashells, which increased the electrical conductivity and hardness of the effluent compared to the influent. The macrophyte exhibited leaf desiccation, possibly due to contact with greywater and its young age (30 days), which may have negatively impacted the system's performance during the vegetated phase. [ABSTRACT FROM AUTHOR]

This study aims to investigate the effect of different seasons (where the temperature would be different) on the performance (phosphorous, nitrogen, and organic matter removal) of sequencing batch reactor (SBR) based wastewater treatment plants. The modified activated sludge model 2D (ASM2d) module, including the microbial kinetics is used to simulate the enhanced biological phosphorus removal (EBPR) SBR process and the temperature is chosen between 10 and 33°C. Influent data from two distinct wastewater treatment plants located in India and Europe are considered. The investigation of the kinetic variables is performed over a wide temperature range, and significant increases are seen as the temperature rises. The effluent parameters are within the government regulations. It is clear that an increase in temperature results in better effluent quality with reduced values of chemical oxygen demand (COD), biological oxygen demand (BOD), ammonium nitrogen and ammonium ions (NH4), and total nitrogen (TN) and a slight increase in total phosphorus (TP) and total suspended solids (TSS). According to the current findings, as the temperature changes from low to high levels, the values of COD, BOD, TN, and NH4 decreased by 2.50, 14.92, 5.80, and 9.90% respectively, for Indian data. There is a slight increase of 1.07% in the TSS profile. In conclusion, this study highlights the importance of considering the effect of different climatic conditions on the performance of SBR-based wastewater treatment plants. [ABSTRACT FROM AUTHOR]

Enhanced biological phosphorus removal (EBPR) in wastewater treatment processes is gaining popularity as a substitute for chemical precipitation because of its cost-effectiveness and decreased production of sludge. Nevertheless, downstream solids processing like sludge digestion, storage, and dewatering can trigger a secondary release of polyphosphate stored within EBPR sludge. This research investigates the use of lanthanum chloride as a coagulant for removing phosphate from liquors produced during the dewatering of EBPR sludge. The hypothesis is that lanthanum can achieve higher orthophosphate removal compared with traditional coagulants like ferric chloride or aluminum sulfate. Results showed that on a molar basis, lanthanum could remove over 99% of orthophosphate from both digested and nondigested EBPR sludge dewatering liquors at metal to phosphate ratios of 1∶1 and 1.1∶1 , respectively. Comparable removal using alum and ferric chloride required higher molar ratios, typically 1.6∶1 or more. Furthermore, in liquors with high initial orthophosphate concentrations (>100 mg/L), lanthanum chloride attained over 85% orthophosphate removal even at pH as low as 2. Conversely, as the dose of ferric chloride increased, the removal rates declined because of significant pH depression. Alum was comparatively the least effective coagulant for removing phosphate for the tested conditions. For low initial orthophosphate concentration solutions (15 mg/L), both ferric chloride and lanthanum chloride attained about 90% removal of orthophosphate at a molar dose ratio of 2∶1. Thus, using ferric chloride as a coagulant is practical in solutions with low initial orthophosphate concentrations. However, for solutions with high initial orthophosphate concentrations (such as return streams from EBPR systems), the potential of lanthanum chloride as a coagulant shows considerable promise. [ABSTRACT FROM AUTHOR]

The multi-soil-layering (MSL) systems is an emerging solution for environmentally-friendly and cost-effective treatment of decentralized rural domestic wastewater. However, the role of the seemingly simple permeable layer has been overlooked, potentially holding the breakthroughs or directions to addressing suboptimal nitrogen removal performance in MSL systems. In this paper, the mechanism among diverse substrates (zeolite, green zeolite and biological ceramsite) coupled microorganisms in different systems (activated bacterial powder and activated sludge) for rural domestic wastewater purification was investigated. The removal efficiencies performed by zeolite coupled with microorganisms within 3 days were 93.8% for COD, 97.1% for TP, and 98.8% for NH 4 +-N. Notably, activated sludge showed better nitrification and comprehensive performance than specialized nitrifying bacteria powder. Zeolite attained an impressive 89.4% NH 4 +-N desorption efficiency, with a substantive fraction of NH 4 +-N manifesting as exchanged ammonium. High-throughput 16S rRNA gene sequencing revealed that aerobic and parthenogenetic anaerobic bacteria dominated the reactor, with anaerobic bacteria conspicuously absent. And the heterotrophic nitrification-aerobic denitrification (HN-AD) process was significant, with the presence of denitrifying phosphorus-accumulating organisms (DPAOs) for simultaneous nitrogen and phosphorus removal. This study not only raises awareness about the importance of the permeable layer and enhances comprehension of the HN-AD mechanism in MSL systems, but also provides valuable insights for optimizing MSL system construction, operation, and rural domestic wastewater treatment. [ABSTRACT FROM AUTHOR]

To investigate the effect of Tetrasphaera's enrichment on phosphorus removal mechanism, three micro-pressure swirl reactor (MPSR) groups were used to experiment on sewage treatment under different SRT (17.2, 50.8, and 68.2 d). Results showed that Tetrasphaera enrichment in the MPSR system was promoted by extending the SRT. After extending the SRT from 17.2 to 68.2 d, the relative abundance of Tetrasphaera increased from 3.1% to 12.1%, and the TP removal efficiency maintained above 92%. The internal circulation results indicated that after extending the SRT, glycogen and polyhydroxybutyrate were co-synthesized during the anaerobic stage, which enhanced the driving force of nutrient removal. Analysis of the microbial composition and functional gene prediction indicated that efficient phosphorus removal can be attributed to the enrichment of Tetrasphaera at long SRT. Overall, the synergistic mechanisms of Tetrasphaera in the organic matter degradation and phosphorus removal processes were integrated into the MPSR. [ABSTRACT FROM AUTHOR]

Phosphorus (P) discharge from anthropogenic sources, notably sewage effluent and agricultural runoff, significantly contributes to eutrophication in aquatic environments. Stringent regulations have heightened the need for effective P removal technologies in wastewater treatment processes. This paper provides a comprehensive review of current P removal methods, focusing on both biological and chemical approaches. Biological treatments discussed include enhanced biological P removal in activated sludge systems, biological trickling filters, biofilm reactors, and constructed wetlands. The efficiency of microbial absorption and novel biotechnological integrations, such as the use of microalgae and fungi, are also examined. Chemical treatments reviewed encompass the application of metal salts, advanced oxidation processes such as chlorination, ozonation, and the Fenton reaction, as well as emerging techniques including the Electro-Fenton process and photocatalysis. Analytical methods for P, including spectrophotometric techniques and fractionation analyses, are evaluated to understand the dynamics of P in wastewater. This review critically assesses the strengths and limitations of each method, aiming to identify the most effective and sustainable solutions for P management in wastewater treatment. The integration of innovative strategies and advanced technologies is emphasized as crucial for optimizing P removal and ensuring compliance with environmental regulations. [ABSTRACT FROM AUTHOR]

The work presents the concept of aerobic granular sludge (AGS) and its potential for wastewater treatment. The work also evaluates the condition of the SBR (Sequencing Batch Reactor) type of municipal wastewater-treatment plant (WWTP) after its reconstruction into a system with AGS. The WWTP parameters achieved before and after reconstruction were compared. Operational measurements of the process during the individual phases of the treatment process showed a balanced concentration profile of the monitored parameters in the span of the semicontinuous cycle. Laboratory tests showed that the sludge from the WWTP has nitrification and denitrification rates comparable to the rates achieved for flocculent sludge, and it is also comparable to the nitrification and denitrification rates of AGS with size of granules below 400 µm. Despite the fact that complete sludge granulation was not achieved, the results measured at the WWTP confirmed the advantages of the AGS concept. Neither anaerobic nor anoxic conditions were identified in the SBR during the individual phases of operation, yet high removal efficiencies of ammonia and nitrate nitrogen and orthophosphate phosphorus were achieved. The concentration of ammonia and nitrate nitrogen at the WWTP effluent was below 5 mg/L, and the concentration of phosphorus was below 0.5 mg/L. [ABSTRACT FROM AUTHOR]

Algal-based waste stabilisation ponds (WSP) are a common wastewater treatment system for small communities but have poor phosphorus removal. Under certain conditions algae in WSPs will perform 'luxury uptake' increasing their phosphorus content to over 3% (gP/gSS) by storing polyphosphate. For the first time in the literature this paper presents a systematic study which determines the conditions needed to maximise phosphorus accumulation within WSP biomass taking into account the interactions between key variables. The key variables of temperature, phosphorus concentration, light intensity, mixing intensity, organic load, and pH were evaluated in 40 batch factorial experiments using a WSP algal culture. All six variables examined had significant main effects or interactions on the phosphorus content of the biomass. These were incorporated into a regression equation which was successfully validated against independent data sets from the literature. The conditions required to maximise the phosphorus content of the biomass were predicted for both summer (high light and high temperature) and winter (low light and low temperature) scenarios. The required conditions were revealed to be high phosphorus concentration, high mixing intensity, no supplementary CO2 addition, and low organic load. Interestingly, these conditions were consistent for both summer and winter suggesting that year-round treatment is possible. Practical methods of achieving these conditions were proposed. While further work will be needed to evaluate the effect of growth and potential influence of algal species, the findings presented provide a vital step towards developing a new phosphorus removal treatment process based on an enhanced understanding of environmental biotechnology. [ABSTRACT FROM AUTHOR]

Phosphorus in wastewater influents is a global issue. Controlling eutrophic water is crucial. Biological phosphorus removal is an economically and environmentally sustainable method for removing phosphorus from wastewater. This study aims to isolate and improve the capacity of aerobic phosphorus-removing bacteria to reduce excessive phosphate concentrations in the environment. Only three out of fourteen bacterial isolates demonstrated the highest phosphate removal efficiency using Toluidine blue-O. Klebsiella pneumoniae 6A, Klebsiella quasipneumoniae 6R, and Enterobacter mori 8R were isolated from activated sludge and identified by 16srRNA. In a single-factor experiment, the effect of incubation periods, phosphate concentrations, carbon sources, sodium acetate concentrations, temperature, pH, and irradiation dosages were studied. Seventy-two hours of incubation, 55 mg/L PO4, sodium acetate as the carbon source, 30°C and pH 7 resulted in maximum phosphorus removal. After optimising the parameters, the removal efficiency of Klebsiella pneumoniae 6A, Klebsiella quasipneumoniae 6R, and Enterobacter mori 8R increased from 73.5% to 85.1%, 79.1% to 98.1%, and 80.6% to 91.9%, respectively. Gamma irradiation showed significant results only in Klebsiella pneumoniae 6A where 100 Gy increased the phosphorous removal efficiency from 85.1% to 100%. Immobilised mixed culture of the three strains adapted better to 100 mg/L Phosphorus than pure cells. Therefore, this technique holds great new promise for phosphorus-contaminated sites bioremediation. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Agro-Environment Science is the property of Journal of Agro-Environment Science Editorial Board and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The use of green methods to treat industrial waste and waste reuse has become a key environmental issue. In order to achieve this goal, this study treated waste phosphogypsum (PG) and produced modified PG biochar to adsorb and remove phosphorus from PG leachate, so that the PG pollution problem was controlled. In this study, PG was modified with sodium carbonate (Na2CO3) to prepare a modified PG biochar that was used for the removal of phosphorus-containing wastewater. An X-ray diffraction (XRD) analysis of the modified PG revealed that the main component was calcium carbonate (CaCO3), and a suitable amount of modified PG could load calcium oxide (CaO) onto the biochar and improve its physical properties. The experimental results showed that the modified PG biochar had a maximum phosphorus adsorption capacity of 132 mg/g. A further investigation of the mechanism of adsorption revealed the importance of electrostatic attraction and chemical precipitation, and it was found that the CaO in the modified PG biochar could effectively facilitate the conversion of phosphate to hydroxylapatite (Ca5(PO4)3OH) in water. The phosphorus removal rate from leachate obtained from a landfill containing PG was 99.38% for a specific dose of the modified PG biochar. In this study, a PG pollution control technology was developed to realize the goal of replacing waste with waste. [ABSTRACT FROM AUTHOR]

Land application of anaerobic digestion (AD) effluent as a fertilizer is desirable for nutrient recycling, but often supplies excess phosphorus (P), which contributes to surface water eutrophication. Reducing the P content in AD effluent filtrate using calcium (Ca) treatment prior to land application is a potential strategy for improving effluent disposal and meeting the discharge standard. This study took flue gas desulphurization (FGD) gypsum, a by-product of coal-fired power plants, as a low-cost Ca source, and combined with traditional phosphorus removal agents to achieve high phosphorus removal efficiency with less chemical cost. As the results showed, FGD gypsum dosages of 20 mmol/L Ca (3.44 g/L) and 40 mmol/L Ca (6.89 g/L) removed up to 97.1% of soluble P (initially 102.8 mg/L) within 60-90 minutes. Combining FGD gypsum treatment with traditional chemical treatments using calcium hydroxide [Ca(OH)2] or ferric chloride (FeCl3) could achieve >99% P removal with reduced chemical costs. This study demonstrated that FGD gypsum is an efficient calcium-based precipitant for phosphorus removal, offering a cost-effective and sustainable approach to enhance wastewater treatment practices and meet discharge standards in wastewater management. [ABSTRACT FROM AUTHOR]

With the continuous deepening of rural revitalization strategy and the increasingly strict sewage discharge standards, rural domestic sewage treatment technology is facing higher challenges and requirements. The combined process of micro-electrolysis + micro-nano bubbles coupled with peroxymonosulfate was constructed in this study, and the treatment effect and application value of this technology were explored with the actual rural domestic sewage as the treatment object. The experimental results showed that under the conditions of HRT of 120 min, PMS dosage of 0. 15 mmol/L, pH = 7, MBs air intake of 15 ml/min, current intensity of 15 A, and Fe/C mass ratio of 1 II, the removal rates of COD, ammonia nitrogen and total phosphorus can reach 88. 55%, 77. 18% and74. 67%, respectively. Under the condition that the pH value of sewage was not adjusted, the non-biochemical simultaneous decarbonization, denitrification and phosphorus removal of rural domestic sewage can be achieved by micro-electrolysis and micro-nano bubbles Coupled with peroxymonosulfate. The concentrations of effluent COD, ammonia nitrogen and total phosphorus met the requirements of the first level standard of the Discharge Standard of Water Pollutants for Rural Domestic Sewage Treatment Facilities (DB45T2413 - 2021). And the comprehensive operating cost was about 1. 15 yuan/m³. [ABSTRACT FROM AUTHOR]

The effect of increased acetate concentration on the process of enhanced biological phosphorus removal was investigated in a sequential batch bioreactor treating synthetic wastewater in a 6-h cycle. Anhydrous sodium acetate was used as the sole carbon source during the experiment and corresponded to a chemical oxygen demand concentration. The phosphate-accumulating organisms were initially cultured for 70 days and the chemical oxygen demand concentration was gradually increased to the final concentration of 1800 mgO2 L−1 under conditions suitable for the growth of the phosphate-accumulating organisms. Successful cultivation of the phosphate-accumulating organisms was only possible if the acetate concentration in the influent did not lead to an excessive concentration of residues in the sludge after the anaerobic phase (estimated at a chemical oxygen demand concentration of 100 mgO2 L−1), which then passed into the aerobic phase. Cultivation continued for the next 67 days. During this time, the sludge was exposed five times to high acetate loading at different concentrations (corresponding to a chemical oxygen demand concentration of 250–1000 mgO2 L−1) to test the performance of the enhanced biological phosphorus removal. High acetate concentrations had no effect on the anaerobic phase of enhanced biological phosphorus removal, as the phosphate-accumulating organisms performed well in anaerobic phosphorus release and acetate assimilation in all five tests. However, the effect of residual acetate in the aerobic phase was detrimental to the aerobic phase of enhanced biological phosphorus removal, as the phosphate-accumulating organisms were prevented from assimilating phosphorus in the aerobic phase. [ABSTRACT FROM AUTHOR]

Constructed wetlands (CWs) are a widely used technology for the treatment of wastewater, with Free Water Surface Constructed Wetlands (FWS CWs) being the simplest configuration. However, there is currently no consensus on the Hydraulic Retention Time (HRT) that optimizes P removal efficiency. To address this issue, this study conducted a bibliometric review of 85 scientific articles published between 1997 and 2021 that investigated the relationship between P removal and the HRT in FWS CWs. Scientometric maps were constructed to identify key topics, and bibliometric surveys were used to refine and explore the relationship between P removal and HRT. The analysis found a high correlation between P removal and HRT across all scales of the FWS CW systems, ranging from moderate to very strong. Specifically, the regressions between P removal efficiency and HRT were 73%, 70%, and 67% for lab-scale, pilot-scale, and real-scale systems, respectively. Overall, the FWS CWs demonstrated strong P removal efficiency, with removal rates reaching 95%, making them a promising technology for the tertiary treatment of effluents with a focus on nutrient removal and recovery. Future studies that focus on the many parameters of CW, especially on how macrophytes management affects the nutrient removal performance of these systems, are necessary to enrich our knowledge of CWs and optimize the application of this technology to wastewater treatment. [ABSTRACT FROM AUTHOR]

This paper presents a study on reducing sewage sludge by an oxic-settling-anaerobic (OSA) pilot plant compared to the conventional activated sludge (CAS) process in view of resource recovery and moving towards plant carbon neutrality. The OSA plant was supplied with real wastewater and the anaerobic reactor was operated under two hydraulic retention times (HRT) (4 and 6 h). Greenhouse gas (GHG) emissions were monitored for the first time to determine the OSA process's production mechanism. The results highlighted that under the lowest HRT (4 h), the removal efficiencies of COD and PO4−P, increased from 75 to 89% and from 39 to 50% for CAS and OSA configurations, respectively. The observed yield coefficient was reduced from 0.58 gTSS gCOD−1 (CAS period) to 0.31 gTSS gCOD−1 (OSA period). A remarkable deterioration of nitrification efficiency under OSA configuration was obtained from 79% (CAS) to 27% (OSA with HRT of 6 h). The huge deterioration of nitrification significantly affected the GHG emissions, with the N2O-N fraction increasing from 1% (CAS) to 1.55% (OSA 4 h HRT) and 3.54% (OSA 6 h HRT) of the overall effluent nitrogen, thus suggesting a relevant environmental implication due to the high global warming potential (GWP) of N2O. [ABSTRACT FROM AUTHOR]

The influence of different modification methods of oyster shells on phosphorus adsorption properties were studied. The effect of different modified concentrations of AlCl3 on phosphorus removal in oyster shells was compared. The results showed that the phosphorus removal rate of 0.5 mol/L AlCl3 modified oyster shells was as high as 90%, and the phosphorus concentration of residual sewage after treatment was 0.05 mg/L. The study compared the treatment effects of natural oyster shells, hot-modified oyster shells and AlCl3 modified oyster shells on low-concentration phosphorus containing wastewater. The TP removal rate were 63% ~ 68%, 61% ~ 72% and 83% ~ 90%, respectively, and the TP removal rate of AlCl3 modified oyster shells were the highest. The adsorption of natural oyster shells, thermal modified oyster shells and AlCl3 modified oyster shells conforms to the quasi-second-order kinetic model and Freundlich isothermal adsorption model, and the adsorption process includes both physical adsorption and chemical adsorption. In the Freundlich isothermal adsorption model, parameter n values of natural oyster shell, hot-modified oyster shell and AlCl3 modified oyster shell were 1.205, 1.168 and 2.611, respectively, indicating that the adsorption reaction of phosphorus on AlCl3 modified oyster shell was easier than that on natural oyster shell and hot-modified oyster shell. [ABSTRACT FROM AUTHOR]

Acclimatization of short-cut denitrifying polyphosphate accumulating organisms (SDPAOs), metabolic mechanism, and operating parameters were analyzed to investigate the performance of the anaerobic/anoxic sequencing batch reactor (A2SBR) process. The high-throughput sequencing technology was employed to explore the microbial community structures of activated sludge systems. The experimental results illustrated that SDPAOs were successfully enriched with three-phase inoculation for 36 days. The removal rates of TP and NO2−-N were 93.22% and 91.36%, respectively, under the optimal parameters of a pH of 7.5, an SRT of 26 days, a temperature of 24 ℃ and a COD of 200.00 mg·L−1 using acetate as the carbon source. In the anaerobic stage, 82.20% external carbon source was converted into 88.78 mg·g−1 PHB, and the removal rate of NO2−-N in the anoxic stage was characterized by ΔNO2−-N/ΔPHB, anoxic ΔP/ΔPHBeffective was 0.289, which was higher than anaerobic ΔP/ΔCODeffective of 0.203. Ignavibacterium and Povalibacter with significant phosphorus removal ability were the dominant bacterial genera. The nitrogen and phosphorus removal could be realized simultaneously in an anaerobic/anoxic sequencing batch reactor. Therefore, this study provided an important understanding of the removal of nitrogen and phosphorus from low-carbon nitrogen wastewater. [ABSTRACT FROM AUTHOR]

Copyright of Inorganic Chemicals Industry is the property of Editorial Office of Inorganic Chemicals Industry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Introduction: Simultaneous chemical phosphorus removal process using iron salts (Fe(III)) has been widely utilized in wastewater treatment to meet increasingly stringent discharge standards. However, the inhibitory effect of Fe(III) on the biological phosphorus removal system remains a topic of debate, with its precise mechanism yet to be fully understood. Methods: Batch and long-term exposure experiments were conducted in six sequencing batch reactors (SBRs) operating for 155  days. Synthetic wastewater containing various Fe/P ratios (i.e., Fe/P  =  1, 1.2, 1.5, 1.8, and 2) was slowly poured into the SBRs during the experimental period to assess the effects of acute and chronic Fe(III) exposure on polyphosphate-accumulating organism (PAO) growth and phosphorus metabolism. Results: Experimental results revealed that prolonged Fe(III) exposure induced a transition in the dominant phosphorus removal mechanism within activated sludge, resulting in a diminished availability of phosphorus for bio-metabolism. In Fe(III)-treated groups, intracellular phosphorus storage ranged from 3.11 to 7.67  mg/g VSS, representing only 26.01 to 64.13% of the control. Although the abundance of widely reported PAOs (Candidatus Accumulibacter) was 30.15% in the experimental group, phosphorus release and uptake were strongly inhibited by high dosage of Fe(III). Furthermore, the abundance of functional genes associated with key enzymes in the glycogen metabolism pathway increased while those related to the polyphosphate metabolism pathway decreased under chronic Fe(III) stress. Discussion: These findings collectively suggest that the energy generated from polyhydroxyalkanoates oxidation in PAOs primarily facilitated glycogen metabolism rather than promoting phosphorus uptake. Consequently, the dominant metabolic pathway of communities shifted from polyphosphateaccumulating metabolism to glycogen-accumulating metabolism as the major contributor to the decreased biological phosphorus removal performance. [ABSTRACT FROM AUTHOR]

Layered double hydroxides (LDHs) have emerged as an efficient and easily prepared class of anion adsorbents, showcasing remarkable potential in the adsorption and recovery of phosphate from wastewater, notably due to their unique "memory effect" post-calcination. This study focuses on the enhancement of phosphate adsorption capabilities of ZnAl layered double hydroxides (ZnAl-LDHs), which are particularly known for their high phosphate affinity, through the incorporation of copper and subsequent modification with ethylenediamine. The resultant ZnAlCu layered trimetallic oxide (ZnAlCu-1%-LDO), post-calcination, was modified with ethylenediamine to produce a novel inorganic metal/organic amine composite adsorbent, designated as ZACen-0.5. Characterization of ZACen-0.5 demonstrated an improvement in surface hydrophilicity, alongside a notable alteration in the adsorbent's skeletal structure, which manifested as degraded granular layers, an increased pore volume, and an enhanced specific surface area. The specific surface area of ZACen-0.5 was found to be 104.61 m2 g-1, marking a 51% increase compared to ZnAlCu-1%-LDO (69.27 m2 g-1). The adsorption capacity of ZACen-0.5 for phosphate was significantly elevated to 271.00 mg P g-1, maintaining an efficiency of 88.2% over four regeneration cycles. The study elucidated the adsorption mechanism of ZACen-0.5, attributing it to monolayer and chemical adsorption processes, which involve electrostatic attraction, ligand exchange, and surface precipitation. In practical wastewater treatment, ZACen-0.5 achieved a phosphate removal efficiency of over 98% from wastewater with an initial phosphate concentration of 3.43 mg P L-1, reducing the phosphate level to 0.0531 mg P L-1, thereby surpassing the stringent firstlevel standard of GB 8978-1996 (0.5 mg P L-1). The findings of this research underscore the effectiveness of ethylenediamine modification of ZnAlCu-1%-LDO in significantly enhancing the phosphate adsorption efficiency of LDH-based materials, presenting a promising avenue for the development of advanced wastewater treatment technologies. [ABSTRACT FROM AUTHOR]

Adsorption is now recognized as an effective and economic method for wastewater treatment. Thus, in recent years, development of low cost adsorbent for dye loaded wastewater remediation has become an important area of research. Algerian phosphate was tested as an effective adsorbent for the removal of cationic dye methylene Blue (MB) as well as the anionic dye blue bezaktiv S-GLD 150 (BB) from synthetic wastewater. The phosphate was characterized by XRD, FT-IR, TGA, SEM, EDX and BET analysis. pHPZC analysis was performed to determine pH sensitive adsorptive removal of cationic and anionic dyes. Batch adsorption experiments of the dyes from aqueous solution were conducted, taking into account the influence of initial dye concentration (10–500 mg/L), adsorbent dosage (1–6 g/L), contact time (5–120 min) and solution pH ((2–12) ± 0.2). The experimental results show that, the adsorption was pH dependent with a high adsorption capacity of MB in basic range and high adsorption of BB in the acidic range. Experimental adsorption data were modeled by different equilibrium isotherms such as Langmuir, Freundlich, Redlich Peterson and Sips. The adsorption process fitted well to pseudo-second-order kinetics and the Langmuir model. The calculated maximum adsorbed quantity qmax of MB and BB were found 30.61 (mg/g) and 20.78 (mg/g) successively. The adsorption process was found to be exothermic in nature in the case of the MB and endothermic for BB. Accordingly; the phosphate has been shown to be a very efficient and low-cost adsorbent, and a promising alternative for eliminating dyes from industrial wastewater. [ABSTRACT FROM AUTHOR]

Nitrogen and phosphorus in freshwaters are a global environmental challenge. Concurrently, the shellfish industry's calcareous waste shells (CWSs) amount to ~10 million tonnes annually. CWSs can effectively adsorb dissolved pollutants, including nutrients, from water, which has motivated a growing number of experimental studies on recycling CWSs in wastewater treatment. This comprehensive literature review summarises and critically assesses the effectiveness of using different CWSs for removing nutrients from water. The effects of CWS type, initial pollutant concentration, adsorbent dosage, particle size, and contact time (CT) are investigated. The results show that phosphorus removal has been examined more than nitrogen. Most studies have been conducted using synthetic wastewater under laboratory conditions only. There is a large variability in experimental conditions, such as CWS adsorbent dosages (0.1–100 g/L) and CT (0.083–360 h). The calcination of CWSs is frequently used to enhance adsorption capacity. The Langmuir isotherm model has been found to fit adsorption data best when raw oyster shells are used, while the Freundlich isotherm is best when the adsorbent is calcinated mussel shells. The pseudo-second-order (PSO) kinetics model tends to describe adsorption data better than the pseudo-first-order (PFO) model in all shell types. There is significant potential for using calcareous waste shells to remove nutrients from wastewater in line with circular economy aspirations. [ABSTRACT FROM AUTHOR]

The harvesting of microalgae biomass cultivated during different processes is still identified as the main driver of biomass production cost. Particularly in the field of wastewater treatment, an energy-efficient and reliable harvesting or separation method is needed to remove microalgae biomass from the wastewater after nutrient assimilation. In this study, the suitability of pile cloth media filtration (PCMF) for microalgae harvesting during wastewater treatment is investigated. A mini plate PCMF was operated over 18 months with three different pile cloth media as part of a pilot-scale wastewater treatment plant incorporating a microalgae treatment step for phosphorus and nitrogen removal. During this time, the removal rates and achievable total suspended solids (TSS) concentration in the effluent were recorded. Differences between the three pile cloth media were noticeable, with TSS concentrations ranging from 9.7 mg·L−1 to 17.7 mg·L−1. The pilot-scale data were used to determine the dimensions of a large-scale PCMF and to estimate its energy demand. This resulted in theoretical energy demands of 7 to 8 Wh·m−3 or 37 Wh·kg−1 TSS, considerably lower than the energy demand of other harvesting technologies. [ABSTRACT FROM AUTHOR]

The traditional water treatment methods may have many shortcomings with increasingly complex pollutants, while the compound bacteria are to combine the strains with different taxonomy and functions, and use the degradation ability of strains to various pollutants and the interactions between strains to achieve safe and efficient removal of pollutants. However, the current studies about the compound bacteria related to water treatment mainly focus on the treatment efficiency of different strain combinations, while the interactions between strains in the compound bacteria are not clear. This review focused on recent studies on the removal of typical pollutants in wastewater by compound bacteria. Starting from the importance of the compound bacteria in the process of water treatment, the acquisition methods of functional strains and the process of constructing compound bacteria were summarized. The research of compound bacteria in water treatment was reviewed from four aspects: nitrogen and phosphorus removal, removal of the common organic matters in domestic sewage, the degradation of heavy metals and emerging contaminants. Based on the research types for the interactions between strains, the research progress of the interactions in compound bacteria was expounded. Finally, the shortcomings and prospects of the compound bacteria for water treatment were discussed from different perspectives, in order to improve the efficiency of compound bacteria in water treatment. [ABSTRACT FROM AUTHOR]

Low P-containing wastewaters (LPWs) exhibit huge P recovery potential, considering their larger volume. P recovery via CaP crystallization using apatite as seed is documented as being potentially well suited for LPWs. However, its responsible mechanisms remain a subject for debate. Taking hydroxyapatite (HAP) as the seed of LPWs, this paper conducted HAP adsorption/dissolution experiments, titration experiments, and P recovery experiments to distinguish the primary responsible mechanism. Results showed that it was HAP dissolution, not P adsorption, that occurred when the initial P concentration was no higher than 5 mg/L, ruling out adsorption mechanism of P recovery from LPWs using HAP as the seed. Significant OH− consumption and rapid P recovery occurred simultaneously within the first 60 s in titration experiments, suggesting CaP crystallization should be responsible for P recovery. Moreover, the continuous increase in P recovery efficiency with seed dosages observed in P recovery experiments seemed to follow well the mechanism of pre-nucleation ion clusters (PNCs) aggregation. During PNCs aggregation, P aggregates with Ca2+ quickly, generating CaP PNCs; then, CaP PNCs aggregate with seed particles, followed by CaP PNCs fusion, and ultimately transform into fines attached to the seed surface. PNCs' aggregation mechanism was further supported by a comparison of seed SEM images before and after P recovery, since denser and smaller rod-shaped fines were observed on the seed surface after P recovery. This study suggests that PNCs' aggregation is the dominant mechanism responsible for the recovery of P from LPWs via CaP crystallization using HAP as the seed. [ABSTRACT FROM AUTHOR]

Significant progress has been made in the study of efficient phosphorus adsorption materials. However, more studies need to be on implementing resourceful recycling of materials after adsorption and phosphorus removal. Therefore, this study analyzed ceramic adsorbent materials prepared from clay supplemented with Al2O3, CaCO3, and their use in the treatment of phosphorus-containing wastewater to minimize phosphorus residues, and the feasibility of its direct use as soil. Many adsorption experiments showed that the optimal conditions for removing phosphorus were pH 6, the dosage of 0.15 g/100 mL, and adsorption time of 16 h, and the total phosphorus removal rate reached 96.77%. Meanwhile, ceramic material has good selective phosphate adsorption under the interference of various anions. The phosphorus removal process of ceramic particles was consistent with quasi-secondary kinetics and Langmuir modeling, and it was the monomolecular layer chemisorption with a maximum adsorption capacity of 21.98 mg/g. Phosphorus removal is achieved by ion exchange, ligand exchange, and chemical precipitation between the metal and phosphate in the ceramic material. The phosphate in solution was mainly combined with aluminum and calcium in the ceramics (Al-P: 63.52%, Ca-P: 33.58%), which plants could utilize accounted for 91.68% (Ca2-P, Ca8-P, Al-P, and Fe-P) of the total phosphorus, indicating that the ceramic materials after adsorption of phosphorus had the potential to be used as a phosphate fertilizer. The seedling growth test showed that the adsorbed phosphorus ceramic grain can increase the available phosphorus content of the soil, enhance the activity of alkaline phosphatase, and promote the growth of soybeans, and humic acid can enhance the phosphorus release ability of the ceramic material. It shows that the adsorbed phosphorus of ceramic materials can be used as fertilizer to realize phosphorus resource utilization. [ABSTRACT FROM AUTHOR]

Arthrospira has the ability to tolerate effluents from domestic to farm wastewater. Food leachate coming from fruits and vegetables can be toxic in water discharge due to high dissolved oxygen and nutrient demands. Thus, pretreatment is required before passing through wastewater treatment plants, which generates higher costs and contamination in water bodies. In this work, leachate from fruits and vegetables was used in different percentages to produce Arthrospira maxima using airlift‐type bioreactors with continuous air flow, two photoperiods, and two inoculums. The treatment with 3% leachate (T1) reached 5.23 g/L after 16 days, while the control reached 3.81 g/L (T0). An optimization of the biomass production was carried out seeking to use the maximum percentage of the leachate, resulting in the best treatment of 9% of leachate (T8) achieving 4.88 g/L. After optimization, three cell disruption methods were applied to the obtained biomass, quantifying amino acids and hydrolysis grade (GH), being the ultrasonication treatment the most important reaching 80% GH and a concentration of 25 mg/g of amino acids, while the unbroken biomass contain 13 mg/g. The Arthrospira maxima species is an algae that can be widely used as a bioremediation method, since it managed to reduce the concentrations of COD and orthophosphates, in addition to containing some of the nutrients that plants require for their development, given that plants require amino acids. During its growth, it is proposed to apply the biomass generated from leachates as a plant biostimulant. [ABSTRACT FROM AUTHOR]

The study aims to analyze the effectiveness of wastewater treatment by using Carica papaya seeds as bio coagulants to diminish total suspended solids (TSS) and excess phosphate. This method has some advantages because it does not use chemical materials, is simple to apply, and is safe for the environment and human health. The wastewater samples were taken from an active laundry site in Palembang City, South Sumatra Province of Indonesia. The study found that the best dosage of coagulant was 3 g for the wastewater samples. The pH and BOD parameters showed slight changes after treatment, with pH 7.63–7.19 and 33–27 mg/L values, respectively. The TSS removal efficiency ranged from 9.3 to 15.6%, while the COD and phosphate removals were obtained from 11.7 to 39.3% and 56.3 to 68.4%, respectively. The treated TSS, COD, and phosphate concentrations have met the Indonesian domestic wastewater quality standard and environmental protection organization (EPO) guidelines. In addition, the statistical analysis and t-test showed significant differences (p < 0.05) for before and after treatment data of all parameters. The ANOVA test showed significant differences (p < 0.05) for all parameters among the three treatments. Overall, the study indicated that C. papaya seeds are promising materials that are eco-friendly and useful to treat laundry wastewater. [ABSTRACT FROM AUTHOR]

The production of sludge-based biochar to recover phosphorus (P) from wastewater and reuse the recovered phosphorus as agricultural fertilizer is a preferred process. This article mainly studied the removal of phosphate (PO4-P) from aqueous solution by synthesizing sludge-based biochar (MgSBC-0.1) from anaerobic fermentation sludge treated with magnesium (Mg)-loading-modification, and compared it with unmodified sludge-based biochar (SBC). The physicochemical properties, adsorption efficiency, and adsorption mechanism of MgSBC-0.1 were studied. The results showed that the surface area of MgSBC-0.1 synthesized increased by 5.57 times. The material surface contained MgO, Mg(OH)2, and CaO nanoparticles. MgSBC-0.1 can effectively remove phosphate in the initial solution pH range of 3.00–7.00, with a fitted maximum phosphorus adsorption capacity of 379.52 mg·g-1. The adsorption conforms to the pseudo second-order kinetics model and Langmuir isotherm adsorption curve. The characterization of the adsorbed composite material revealed the contribution of phosphorus crystal deposition and electrostatic attraction to phosphorus absorption. [ABSTRACT FROM AUTHOR]

In order to treat phosphorus-containing wastewater and realize the resource utilization of wetland plant residues, biochar was prepared by the pyrolysis of canna aquatic plant waste at 700 °C, and the adsorption characteristics of phosphorus by MgO-modified biochar (MBC) were explored. The main results are as follows: the adsorption capacity of the MBC was eight times that of unmodified biochar (BC), and the adsorption capacity was up to 244 mg/g. The isothermal adsorption data were consistent with the Langmuir equation, which indicates monolayer adsorption. The functional groups changed little before and after the modification, but a new diffraction peak appeared after the modification. Compared with the standard card, it was suggested that there were MgO crystals with a higher purity. SEM images showed that the BC had a smooth surface, an obvious pore structure, and a thin pore wall, while the MBC had a rough surface and a layered structure, which can provide more adsorption sites for phosphate adsorption. In addition, an XPS analysis showed that Mg3(PO4)2 crystals appeared on the surface of the MBC after adsorption. The mechanism analysis showed that MgO is an important substance for MBC to adsorb phosphorus, and electrostatic adsorption and complex precipitation play key roles. In the test to verify the removal of actual phosphorus-containing wastewater by MBC, it was found that the removal rates for wastewater with 2.06 mg/L and 199.8 mg/L of phosphorus by MBC were as high as 93.4–93.9% and 99.2–99.3%, respectively. MBC can be used as an efficient adsorbent for phosphorus removal. [ABSTRACT FROM AUTHOR]

The use of wastewater for microalgae cultivation allows the removal of contaminants through microalgal metabolism, contributing to the reduction of production costs, which improves the sustainability of the process. The objective of this work was to utilize malting wastewater as an alternative medium for microalgae cultivation, with the aim of increasing the carbohydrate productivity in microalgal biomass. To achieve this, six strains of microalgae (Chlorella minutissima, Chlorella homosphaera, Spirulina platensis LEB 52, Spirulina platensis Paracas, Scenedesmus obliquus, and Synechococcus nidulans) were cultivated in their standard medium with 30% malting wastewater added. In this initial stage (Erlenmeyer flasks: 1.8 L final volume), Spirulina platensis LEB 52 demonstrated high efficacy in removing nitrate (93%) and phosphate (90%) from wastewater. Furthermore, this strain exhibited the highest carbohydrate productivity (27 mg/L.day) and was therefore selected for scale-up in open raceway pond cultivation (250 L) with 50% wastewater added. During the second step, after 15 days of cultivation, Spirulina platensis LEB 52 reduced the phosphate and nitrate concentration in 76.6% and 48%, respectively, while attaining a carbohydrate productivity of 12.26 mg/L.day. These findings demonstrate a potential way for malting wastewater treatment and valorization, reducing pollution risks and the costs of microalgae cultivation, while generating biomass with different biotechnological applications, especially for biofuels production. Therefore, this approach represents a promising strategy for microalgae-based biorefinery. [ABSTRACT FROM AUTHOR]

Phosphate (P) is a major pollutant that leads to deterioration and pollution of natural water quality as well as the death of living organisms in those waters. With the rapid increase in the world population and incorrect disposal of wastewater, water pollution with P increases; therefore, reduction of it has received significant attention in the scientific community. This paper reviews the reported literature on traditional methods used to remove P from water and the advantages and disadvantages of each of them, in addition to discussing the application of modern adsorption technology to remove P from water using metallic nanomaterials, and discusses their unique properties and high adsorption capacity of P from water, then highlights the challenges and multiple gaps that may affect the efficiency of the removal process, in order to reach the best and fastest technology to remove P from water with the highest efficiency and the lowest possible cost. [ABSTRACT FROM AUTHOR]

In this study, the removal efficiency of chemical oxygen demand (COD), color, turbidity, phosphate, and nitrate from wet coffee processing wastewater by pulsed-electrocoagulation process (PECP) was examined with various factors such as pH: 3–11, reaction time: 15–75 min, current: 0.150–0.750 Amp, and electrolyte concentration: 0.25–1.25 g/L. Several operational parameters for the treatment of wet coffee processing wastewater utilizing the PECP have been optimized through the application of the surface response design technique, which is based on the central composite design. A quadratic model helped estimate the percentage removal of COD, color, turbidity, phosphate, and nitrate with power consumption under various situations. It also evaluated the significance and their interaction with independent variables using analysis of variance (ANOVA). Through the use of statistical and mathematical techniques, optimum conditions were determined in order to remove the maximum pollutant and nutrient while using the minimum of power. The results showed that the removal of COD—98.50%, color—99.50%, turbidity—99.00%, phosphate—99%, and nitrate—98.83%, with a power consumption of 0.971 kWh m−3 were achieved at pH-7, NaCl dose of 0.75 g/L, electrolysis duration of 45 min, and current of 0.45 Amp. Therefore, under the different operating conditions, the PECP demonstrated to be a successful technique for pollutant removal from wastewater and industrial effluent. [ABSTRACT FROM AUTHOR]

The presently increasing global population demands increased food production. Consequently, phosphate – an indispensable fertilizer component – will be needed in ever greater amounts. Current levels of mining of phosphate's most important constituent element, phosphorus (P), are unsustainable, and P rock is predicted to soon be completely depleted. Because P is a non‐renewable resource, techniques to recover and reuse waste phosphate are necessary. Large amounts of unused phosphate exist in both municipal and agricultural wastewater streams, as well as in sewage sludge. Approaches to recovering phosphate from these sources fall into three main categories: biological, chemical, and electrochemical. Biological phosphate recovery has seen some plant‐scale use, but significant drawbacks including the complication of operation have prevented it from becoming widespread. The most common method of phosphate recovery, chemical phosphate recovery, has been applied at scale with success due to the stability and reliability of the process. However, disadvantages such as the exorbitant amounts of alkali dosing required to maintain the high pH necessary for phosphate precipitation leave room for improvement. In recent years, electrochemical phosphate recovery has gained traction because of its potential to overcome the weaknesses of traditional chemical approaches by utilizing water electrolysis to induce a high pH without the need for an added base. But before plant‐scale electrochemical methods can be considered economically viable, the steep energy requirements of water electrolysis must be mitigated through the development of improved electrocatalysts or circumvented through the discovery and application of new electrochemical processes to generate hydroxyl ions needed to induce a high pH. In this review, the three broad categories of phosphate recovery techniques are discussed and an outlook on the future of electrocatalysis for phosphate recovery is presented. Particularly, the requirements for improved and Earth‐abundant electrocatalysts are considered alongside a critical discussion of the possibility of a decentralized network of onsite wastewater treatment facilities powered by renewable electricity. [ABSTRACT FROM AUTHOR]

Discharges of nitrogen and phosphorus from wastewater continue to be a widespread environmental problem causing eutrophication and harm to aquatic environments. In this study, the NH 4 +-N and PO 4 3--P adsorption capacity of a casting dust-based polymer (FDG) synthesized from casting dust (FD), and a FDG modified by MgO to obtain magnesium modified geopolymer (MFDG), were investigated. FDG was found to have almost zero capacity to adsorb PO 4 3--P, while adsorption of NH 4 +-N and PO 4 3--P by MFDG fitted well with the Langmuir model and the pseudo-second-order kinetic model. The maximum adsorption capacity of NH 4 +-N and PO 4 3--P by MFDG was 230.69 mg/g and 175.09 mg/g, and its adsorption capacity of NH 4 +-N was 18.3 times higher than that of FDG. pH 9 was found to be optimal for adsorption of NH 4 +-N and PO 4 3--P by MFDG and the NH 4 +-N and PO 4 3--P reaction with Mg2+ to form struvite is the main process. Penetration times for NH 4 +-N and PO 4 3--P were about 200 h and 40 h when an adsorption column filled with MFDG was used to purify swine wastewater with flow rate of 2 mL/min. These results demonstrated that MFDG is a good absorbent, and could have an important application in treatment of wastewater. [ABSTRACT FROM AUTHOR]

A new adsorbent called iron-magnesium oxide coupled lignite (CIMBC) was developed to address the challenges of recovering high concentrations of ammonia nitrogen and phosphate in livestock farm wastewater and improving the inefficient use of lignite (BC) with low calorific value. CIMBC was synthesized using the modified ferromagnesium salt double-coating method. The experiments demonstrated that Fe2O3 and MgO could be effectively loaded onto the surface of BC at a Fe/Mg molar ratio of 1:2 and pyrolysis temperature of 500 °C. The optimal conditions for adsorption were determined to be an N/P concentration ratio of 2:1, adsorbent dosage of 1 g/L, and pH of 7. The presence of coexisting cations (Ca2+ and Mg2+) inhibited the removal of ammonia nitrogen but enhanced the removal of phosphate. Likewise, the presence of coexisting anions (CO32− and SO42−) hindered the removal of both ammonia nitrogen and phosphate. The adsorption behavior followed the pseudo-second-order model and the Langmuir model, with a maximum adsorption capacity of 95.69 mg N/g for ammonia nitrogen and 101.32 mg P/g for phosphate. The adsorption process was a spontaneous endothermic process controlled by multiple levels. The main mechanisms of adsorption involved electrostatic attraction, intra-particle diffusion, ion exchange, chemical precipitation, and coordination exchange. After 5 times of adsorption–desorption, the recovery rate of CIMBC is less than 50%, and the removal rate of phosphate is less than 40%. Although the RCIMBC exhibited low reusability, but also it showed potential in removing heavy metals (Pb) from wastewater and for use as a slow-release fertilizer. CIMBC is a promising new adsorbent, which can realize resource utilization of lignite with low calorific value while removing nitrogen and phosphorus. [ABSTRACT FROM AUTHOR]

High wastewater production rates during the past few decades are mostly attributable to anthropogenic activities. The main components leading to the nutrient enrichment of natural water bodies are such as nitrogen, phosphorus, and other minerals. The main focus of this research was to assess the ability of using Chlorella vulgaris algae, a potent and environmentally benign material, to eliminate phosphate and nitrate ions from wastewater. FTIR results showed that the biologically active molecules that facilitate the binding of phosphate and nitrate ions unto the C. vulgaris are C=C and N–H amid. The ideal equilibrium time for adsorption was 24 h with an optimum pH of 7 and the mass ratio of algae and different anions concentration was 80%. Freundlich isotherm model was the best-fitted isotherm. Moreover, the results of the experiment fit more closely with the pseudo-second-order kinetic model than other models. Elovich kinetic model data for both ions showed that the adsorption rate was much higher than the desorption rate. The growing popularity of biosorbents in treating wastewater has led to an improvement in their affordability and availability, and C. vulgaris may now represent an environmentally friendly choice from an environmental, and economic standpoint. [ABSTRACT FROM AUTHOR]

Since currently used natural, nonrenewable phosphorus resources are estimated to be depleted in the next 30–200 years, phosphorus recovery from any phosphorus-rich residues has attracted great interest. In this study, phosphorus recovery from complex wastewater samples was investigated using continuous adsorption on cryogel column composited calcium silicate hydrate nanoparticles (CSH columns). The results showed that 99.99% of phosphate was recovered from a synthetic water sample (50 mg L−1) using a 5 cm CSH column with a 5 mL min−1 influent flow rate for 6 h while 82.82% and 97.58% of phosphate were recovered from household laundry wastewater (1.84 mg L−1) and reverse osmosis concentrate (26.46 mg L−1), respectively. The adsorption capacity decreased with an increasing flow rate but increased with increasing initial concentration and column height, and the obtained experimental data were better fitted to the Yoon–Nelson model (R2 = 0.7723–0.9643) than to the Adams–Bohart model (R2 = 0.6320–0.8899). The adsorption performance of phosphate was decreased 3.65 times in the presence of carbonate ions at a similar concentration, whereas no effect was obtained from nitrate and sulfate. The results demonstrate the potential of continuous-flow phosphate adsorption on the CSH column for the recovery of phosphate from complex wastewater samples. [ABSTRACT FROM AUTHOR]

Elevated concentrations of phosphorus (P) and other nutrients common in wastewater treatment plant (WWTP) effluent have been shown to contribute to the proliferation of harmful algal blooms, which may lead to fish kills related to aquatic hypoxia. Increased understanding of the negative effects associated with elevated P concentrations have prompted more strict regulation of WWTP effluent in recent years. The use of low‐cost and potentially regenerative adsorptive phosphate filters has the potential to decrease P concentrations in WWTP effluent released to natural waters. This research focuses on assessing the capacities of recycled concrete aggregate (RCA), expanded slate, and expanded clay to remove phosphate from P‐amended WWTP effluent. Results from a flow‐through column study indicate that RCA consistently removed an average of 97% of phosphate over 20 weeks of continuous flow at an 8‐hour hydraulic retention time (HRT). Expanded clay removed an average of 63% of introduced phosphate but decreased in removal capacity from 91 to 42% over the 20‐week duration. Sorption data from batch studies were fitted to Langmuir models and RCA was shown to have the highest maximum sorption capacity (6.16 mg P/g), followed by expanded clay (3.65 mg P/g). RCA and expanded clay are promising options for use in passive filters for further reduction of phosphate from WWTP effluent. [ABSTRACT FROM AUTHOR]

Unnecessary discharge of nutrient-rich aquaculture wastewater is a significant threat to the environment, exacerbating massive resource wasting worldwide. Microalgae-based circular economy strategies utilize atmospheric CO2 and aquaculture wastewater nutrients and convert them into valuable compounds. Lutein, a natural pigment, is a nutritional supplement for eye protection, anti-cancer and anti-inflammatory effects, and other health benefits. It is widely utilized in the food and pharmaceutical industries. The primary purpose of this study is to reuse aquaculture wastewater to grow microalgae and optimize conditions to achieve a high yield of lutein as well as the removal of nutrients from wastewater. When cultured in 1.0× BG11 nutrient-added aquaculture wastewater and aerated using 2% CO2, the biomass concentration and lutein content of Chlorella sorokiniana NIES-2168 increased to 1.78 g L−1 and 7.43 mg g−1, respectively. A two-stage culture strategy further increased the lutein content and yield of microalgae. The highest lutein content of 13.95 mg g−1 and lutein productivity of 3.63 mg L−1 d−1 in the second stage aligned with other phototrophic microalgae currently used for lutein production. C. sorokiniana NIES-2168 also showed exceptional nitrogen and phosphorus removal efficiency, with nitrate and phosphate removal rates reaching 96.07% and 96.75% during the two-stage culture process. [ABSTRACT FROM AUTHOR]

Introduction: Nanoparticles play a vital role in environmental remediation on a global scale. In recent years, there has been an increasing demand to utilize nanoparticles in wastewater treatment due to their remarkable physiochemical properties. Methods: In the current study, manganese oxide nanoparticles (MnO-NPs) were synthesized from the Bacillus flexus strain and characterized by UV/Vis spectroscopy, X-ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy. Results: The objective of this study was to evaluate the potential of biosynthesized MnO-NPs to treat wastewater. Results showed the photocatalytic degradation and adsorption potential of MnO-NPs for chemical oxygen demand, sulfate, and phosphate were 79%, 64%, and 64.5%, respectively, depicting the potential of MnO-NPs to effectively reduce pollutants in wastewater. The treated wastewater was further utilized for the cultivation of wheat seedlings through a pot experiment. It was observed that the application of treated wastewater showed a significant increase in growth, physiological, and antioxidant attributes. However, the application of treated wastewater led to a significant decrease in oxidative stress by 40%. Discussion: It can be concluded that the application of MnO-NPs is a promising choice to treat wastewater as it has the potential to enhance the growth, physiological, and antioxidant activities of wheat seedlings. [ABSTRACT FROM AUTHOR]

The excessive amount of phosphate is a critical issue in several countries since this leads to eutrophication that may result in algal bloom. Biosorption processes are currently gaining recognition to remove wastewater contaminants since the sorbent source can either be alive or dead, which, for the latter can be beneficial in terms of end-of-life utilization as well as cost. Response surface methodology (RSM) design was used to evaluate the effect of pH, contact time, initial phosphate concentration, and biosorbent dosage in the percent removal of inorganic phosphate from simulated wastewater with an alga (Caulerpa lentillifera) as the biological raw material. This method of experimental design concentrated on using a specific window for each parameter and obtaining the most optimal combination of these parameters by comparing their predicted and actual responses to better understand their interactive effects. The raw seaweed was subjected to drying and size reduction for it to become powder form. This algal powder used was characterized by Fourier Transform Infrared Spectroscopy to determine the functional groups present. The highest percent removal obtained in the experiment proper was 42.29 % on average. The data from the experiment proper was assessed by making use of a statistical analysis software, JMP® (SAS institute), and showcased about 45.46 % as the predicted optimum percent phosphate removal. Running the test based on the best parameter combination and comparing the actual percentage removal resulting from the validation provided only a 3.89 % difference to the predicted value of the software. Analysis of variance (ANOVA) was applied to the RSM results, and the predicted R2 value, as well as that of the adjusted R2 was found to have good interaction with each other with the difference between the values much less than 0.2. [ABSTRACT FROM AUTHOR]

Microalgae are diverse in nature, capable to survive under diverse environmental conditions, and a good method of choice for remediation of polluted waters. Desmodesmus is a recently updated genus having capacity to consume wastewater nutrients under heterotrophic growth conditions. The aim of this study is to investigate the potential of Desmodesmus subspicatus for the treatment of wastewater. The treatment of wastewater was carried out for the period of 20 days at ambient temperature under continuous (24 hr) illumination of 4750 lm by a LED source withaeration at rate of 3.5 L/min by air pump. Treated wastewater samples with microalgae were then analysed for pH, total dissolved solids (TDS), biological oxygen demand (BOD), chemical oxygen demand (COD), ammonia as NH4+ phosphate and nitrate on every 5th day during experiment to monitor the remediation process. The results showed that D. subspicatus significantly lowered COD (84%) and BOD (76%) levels. The removal efficiency of ammonia was maximum (approximately 100%), nitrate (91%), and phosphate (71%) from wastewater was also prominently observable. The treatment effectively reduced (80%) TDS up to permissible limits. D. subspicatus can growin nutrient rich waters and has the potential of remediation under photoautotrophic conditions. [ABSTRACT FROM AUTHOR]