Search

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]

Vertical oxidation pond operated in sequencing batch mode (HRT: 1.25 day) with duckweed as the vegetation was used to acclimatize with simulated agricultural wastewater. The maximum removal rate of urea [371 g/(m3.d)] and COD [222.4 g/(m3.d)] were observed at moderate concentrations of urea (500 mg/L), N-P-K (60 mg/L), and pesticide (20 mg/L). Inhibition and toxicity posed by higher concentrations, decreased the removals of urea (83% to 61%), COD (81% to 51%), and TDS (76% to 50%) at the end of the acclimatization. Steady removal (> 99%) of PO43−-P was observed during acclimatization. Effluent pH increased due to the generation of NH4+-N (maximum 370 ± 5 mg/L) from the assimilation of urea. Oxidation of ammonia led to the maximum generation of NO2−-N and NO3−-N of 10 mg/L and 9 mg/L, respectively. Particles less than 300 μm increased, and both specific gravity (from 2.62 to 2.42) and maximum dry density (from 1.73 to 1.30 g/cm3) of the base soil decreased with an increase in urea, N-P-K, and pesticide. Reactor biomass increased (1.42 to 1.90 g/L) up to initial concentrations of urea (500 mg/L), N-P-K (60 mg/L), and pesticide (20 mg/L), then decreased (1.68 g/L) with an increase in concentration. [ABSTRACT FROM AUTHOR]

Anaerobic oxidation of methane (AOM) is capable of coupling the reduction of various substrates, which plays a crucial role in accelerating the abatement of pollution. In this study, we employed a sequencing batch reactor (SBR) to enrich a mixed consortium that included AOM microbes and examined the ensuing microbial reduction of tellurate. To obtain the mixed consortium, we enriched AOM microbes in anaerobic conditions utilizing methane as the only electron donor, with nitrate serving as the electron acceptor. We evaluated the abundance of typical methane-oxidizing microbes and associated genes in the reactor using quantitative PCR. Notably, the enriched microbes were able to achieve microbial tellurate reduction and produce elemental tellurium. An analysis of community structure further indicated the vital roles of methanotrophs, denitrifiers, and other heterotrophs in the reactor, although their molecular mechanisms require further investigation. These findings underscore the role of enriched microbial communities in tellurate reduction using a lab-scale SBR, laying the groundwork for future studies into the mechanism of this process, which utilizes methane as an electron donor. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the influencing factors and characteristics of granule morphology through approximately 500 d of long-term monitoring of two types of anaerobic–aerobic phosphorus-accumulating organism (PAO) and anaerobic–anoxic denitrifying PAO (DPAO) sequencing batch reactors (SBRs). The results show that granules were present in the DPAO SBR and PAO SBR after 200 d and 250 d of operation, respectively. The average diameters of the granules were 2.2 ± 0.7 mm in the DPAO SBR and 0.4 ± 0.3 mm in the PAO SBR, respectively. The DPAO granular sludge contained rod-shaped microorganisms, whereas the PAO granular sludge contained cocci-type microorganisms. A precipitated core consisting of hydroxyapatite was found in the DPAO granules. A comparative analysis conducted under various operating conditions revealed that the availability and type of the electron acceptors (EAs) may have a significant impact on granulation. This observation suggests that the presence and diversity of EAs are crucial factors for the development of different granule sizes and morphologies. [ABSTRACT FROM AUTHOR]

Coconut fiber waste has the potential to become a value-added product as a biofilm media and an adsorbent. The addition of biofilm media and adsorbent is important because it reduces the amount of sludge produced in wastewater. Furthermore, the quality of wastewater produced by the Integrated Anoxic-Oxic Sequencing Batch Reactor (IASBR)process with the addition of biofilm media and adsorbents can be used as clean water. The wastewater used comes from apartment wastewater. The Integrated Anoxic-Oxic Sequencing Batch Reactor was used to determine the optimal anoxic-aerobic processing time in a tropical climate. The study will further compare the efficiency of the two by using discarded coconut fiber as an additional adsorbent and biofilm media. The optimal adsorbent dose and weight of waste coconut fiber, as well as hydraulic retention time optimization, were all examined. As a result, clean water was discovered to be the primary product after the addition of adsorbent and biofilm media made from waste coconut fiber. [ABSTRACT FROM AUTHOR]

Sequencing batch reactors (SBRs) are devices widely used in wastewater treatment, chemical engineering, and other areas. They allow for the sedimentation and compression of solid particles of biomass simultaneously with biochemical reactions with nutrients dissolved in the liquid. The kinetics of these reactions may be given by one of the established activated sludge models (ASMx). An SBR is operated in various stages and is equipped with a movable extraction and fill device and a discharge opening. A one-dimensional model of this unit can be formulated as a moving-boundary problem for a degenerating system of convection-diffusion-reaction equations whose unknowns are the concentrations of the components forming the solid and liquid phases, respectively. This model is transformed to a fixed computational domain and is discretized by an explicit monotone scheme along with an alternative semi-implicit variant. The semi-implicit variant is based on solving, during each time step, a system of nonlinear equations for the total solids concentration followed by the solution of linear systems for the solid component percentages and liquid component concentrations. It is demonstrated that the semi-implicit scheme is well posed and that both variants produce approximations that satisfy an invariant region principle: solids concentrations are nonnegative and less or equal to a set maximal one, percentages are nonnegative and sum up to one, and substrate concentrations are nonnegative. These properties are achieved under a Courant-Friedrichs-Lewy (CFL) condition that is less restrictive for the semi-implicit than for the explicit variant. Numerical examples with realistic parameters illustrate that as a consequence, the semi-implicit variant is more efficient than the explicit one. [ABSTRACT FROM AUTHOR]

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.)

In this study, the removal of chemical oxygen demand (COD), ammonium nitrogen (NH4+‐N) and total inorganic nitrogen (TIN) in a three‐step fed anoxic/aerobic sequencing batch reactor was investigated. Response surface methodology (RSM) was used to determine and optimize the effect of operating parameters such as the ratio of aerobic/anoxic (Ae/Ax) phase durations, percentage of feeding to the first anoxic phase (R1) and ratio of feeding percentages to the third and second anoxic phases (R3:R2). The results of the analysis of variance (ANOVA) showed that the three independent variables were statistically highly significant (p < 0.0001). The values of the determination coefficient (R2) for the removal efficiency of COD, NH4+‐N and TIN was 0.9558, 0.9334 and 0.9963, respectively, indicating a good agreement between the experimental results and the predicted values. The quadratic model was valid in predicting experimental results. The optimum conditions obtained using the desirability function were found to be 2.05 for the ratio of Ae/Ax phase durations, 43.09% for R1 and 0.86 for R3:R2, where the COD, NH4+‐N and TIN removal efficiency was 94.29, 97.83 and 86.86%, respectively. As a result of the evaluation of the interactive effect of the independent variables, it was determined that R1 was the most effective factor. The results showed that RSM could be used for optimization of operating parameters and improvement of efficiency in a three‐step fed anoxic/aerobic sequencing batch reactor. [ABSTRACT FROM AUTHOR]

This study proposed an AO-SBR (Anaerobic Aerobic Sequencing Batch Reactor) combined with iron-carbon micro-electrolysis (ICME) particles system for sewage treatment at low temperature and explored the dephosphorisation mechanism and microbial community structure. The experimental results illustrated that ICME particles contributed to phosphorus removal, metabolic mechanism of poly-phosphorus accumulating organism (PAO) and microbial community structure in the AO-SBR system. The optimal treatment effect was achieved under the conditions of pH 7, DO 3.0 mg/L and particle dosage of 2.6 g Fe-C/g MLSS, and the removal rates of COD, TP, NH4+-N and TN reached 80.56%, 91.46%, 69.42% and 57.57%. The proportion of phosphorus accumulating organisms (PAOs) increased from 4.54% in the SBR system to 10.89% in the ICME-SBR system at 10°C. Additionally, the metabolic rate of PAOs was promoted, and the activities of DHA and ETS both reached the maximum value of 13.34 and 102.88 μg·mg−1VSS·h−1. These results suggest that the ICME particles could improve the performance of activated sludge under low-temperature conditions. This technology provides a new way for upgrading the performance of sewage treatment in the cold area. [ABSTRACT FROM AUTHOR]

This study evaluates the performance of a simple sequencing batch reactor (SBR) with conical geometric configuration in terms of aerobic granulation and simultaneous removal of COD, nitrogen, and phosphorous from synthetic wastewater. The reactor was operated for 328 days in 3 different phases. Stable granules measuring around 0.9±0.3 mm with good settling properties were formed in phase III of operation. Optimum removals of COD (90%), NH4+-N (91%), total nitrogen (87%), and PO43--P (83%) were achieved in phase III, while the influent concentrations were COD (640±32 mg/L), NH4+-N (53±2.5 mg/L), and PO43--P (9±0.6 mg/L). Mixed liquor suspended solids increased from 0.26 g/L to 2.3 g/L while sludge volume index (SVI30) decreased from 380 mL/g to 65 mL/g during start-up to end of the study, respectively. The conical geometry induces an effective velocity gradient along with aeration in the reactor for better flocculation of biomass which has a good impact on the formation of stable and resistant aerobic granules. This system in conical SBR is advantageous as it attains simultaneous nutrient removal (CNP) with effective biomass retention without automatic process control. This treatment system has the potential to employ in low volume wastewater treatment in many decentralized applications. [ABSTRACT FROM AUTHOR]

Objective: The objective of the present work was to reduce the start-up time of aerobic granular sludge (AGS) formation using medium-strength sewage and to find the most effective anaerobic, aerobic (oxic), and anoxic (A/O/A) cyclic time distribution over the 6 h cycle time for the removal of nutrients. Methods: A rectangular sequencing batch reactor (SBR) operated systematically in A/O/A cycle was designed for AGS formation. In order to achieve complete nutrient removal, the anoxic phase (5% of the total cycle duration) was introduced in the SBR cycle. Results: Growth in the biomass profile was observed after 20 days of operation, and complete granulation was achieved within 35 days of operational studies. Regular-shaped, compact granules with visible outlines and clear boundaries predominate inside the system, with an average particle size of 220.19 µm. The A/O/A system achieved average removal efficiencies of 70.02±5.98%, 78.21±18.66%, 60.62±9.69%, and 53.49±8.14% for COD, NH4+-N, TN, and PO43--P, respectively. The reasons for poor COD and PO43--P removal performance were the short anaerobic phase (25% of total cycle duration of 6 h) and higher biomass concentration. However, the long aerobic phase (60% of total cycle duration of 6 h) with the anoxic phase achieved outstanding (100%) NH4+-N removal efficiency after the system reached a steady state. SEM results inferred that Rod-shaped bacteria, Cocci, and Filamentous fungi were the dominant microorganisms found within the cultivated granules. Conclusions: Sewage with a high COD loading rate accelerates AGS formation and development within an A/O/A cycle SBR reactor. The rapid granulation and simultaneous removal of organics and nutrients by the A/O/A mode SBR without any support materials provide an alternative for wastewater treatment. [ABSTRACT FROM AUTHOR]

Biogranulation has emerged as a viable alternative biological wastewater treatment approach because of its strong biodegradability potential, toxicity tolerance, and biomass retention features. However, this process requires a long duration for biogranules formation to occur. In this study, magnetic powder activated carbon (MPAC) was used as support material in a sequencing batch reactor to enhance biogranules development for wastewater treatment. Two parallel SBRs (designated R1 and R2) were used, with R1 serving as a control without the presence of MPAC while R2 was operated with MPAC. The biodegradability capacity and biomass properties of MPAC biogranules were compared with a control system. The measured diameter of biogranules for R1 and R2 after 8 weeks of maturation were 2.2 mm and 3.4 mm, respectively. The integrity coefficient of the biogranules in R2 was higher (8.3%) than that of R1 (13.4%), indicating that the addition of MPAC improved the structure of the biogranules in R2. The components of extracellular polymeric substances were also higher in R2 than in R1. Scanning electronic microscopy was able to examine the morphological structures of the biogranules which showed there were irregular formations compacted together. However, there were more cavities situated in R1 biogranules (without MPAC) when compared to R2 biogranules (with MPAC). Dye removal reached 65% and 83% in R1 and R2 in the post-development stage. This study demonstrates that the addition of MPAC could shorten and improve biogranules formation. MPAC acted as the support media for microbial growth during the biogranulation developmental process. [ABSTRACT FROM AUTHOR]

Although wastewater treatment plants are considered hotspots for the spread of antibiotic-resistant bacteria (ARB) and antibiotic-resistant genes (ARGs), few studies have explored the mechanisms underlying the emergence of multidrug-resistance. Using four sequencing batch reactors under fluctuating concentrations of levofloxacin (LVX), we isolated 440 isolates, which were identified based on the sequence of the 16 S rRNA gene and growth at 37 ºC, focusing on potential human pathogens. We then evaluated the multidrug-resistance of 62% of these isolates by determining the minimum inhibition concentration (MIC) of erythromycin, tetracycline, chloramphenicol, and LVX in the emergence of ARB. The average MIC was increased more than 100-fold in the first exposure, whereas did not show the same response after re-exposure due to different LVX concentrations between the 2 conditions. We identified 33 Acinetobacter baumannii isolates that emerged only during re-exposure, especially in R-2 and R-3, in which the LVX concentration was changed from 4 and 16 mg/L, respectively, to 128 mg/L. Moreover, we assessed the disinfection efficiency of chlorine/UV treatment against pathogenic ARB. The growth of multidrug-resistant A. baumannii isolates was decreased by 0.9–7.4 log 10 following disinfection treatment with > 0.5 mg /L Cl 2 or > 30 min UV irradiation. [Display omitted] [ABSTRACT FROM AUTHOR]

This study aims to investigate, the effect of organic loading rates (OLRs), nutrient ratio addition, and sludge retention time (SRT) on treating dairy wastewater in a sequencing batch reactor (SBR) system. This investigation is verified by experiments conducted in 3 phases at 3 different OLRs (1.8, 1.2, and 0.9 kg/m³d, respectively). Urea ((NH2)2CO) is added to make a suitable (COD:N:P) ratio of (100:5:1) in dairy wastewater. The SRT is adjusted from 50 days to an appropriate value of 18 days. The obtained results show that the COD, TN, and TP removal efficiencies are increased with decreasing OLRs. Sludge concentration in the SBR tank is stable at 1100 mg/L after adding (NH2)2CO. In addition, the SBR operated at a suitable SRT (i.e. 18 days) helps the biomass stably, resulting in enhancement of COD, TN, and TP removal. The results are helpful to the design of SBR for treating dairy wastewater. [ABSTRACT FROM AUTHOR]

Industrial pollution discharges from washing fuel oils pose severe problems for the environment, particularly for the marine environment receiving these discharges. This work evaluates the biological treatment performance of wastewater (90 m3/h) rich in organic matter with low biodegradability using a sequential batch reactor (SBR) on a laboratory scale. The test using SBR was carried out for 25 days on a continuous cycle of 24 h (30 min of filling, 17 h of aeration, 4 h of anoxia, 2 h of settling, and 30 min of emptying). The feasibility of alternative sources of microorganisms from urban wastewater. The performance of the batch sequencing reactor was evaluated using turbidity, total suspended solids, chemical oxygen demand (COD), biological oxygen demand (BOD), ammonium, nitrate, and phenol as indicators. The results obtained showed that the COD/BOD ratio and the pollutant load vary from one campaign to another. The removal efficiency of COD, BOD, TSS (Total suspended solids), ammonium, nitrate, and phenol varies from 81%, 91%, 72%, 100%, 52%, and 63%. Thus, SBR-type treatment could be an interesting way to reduce pollution due to its simplicity, less space occupation, low energy consumption, and not requiring highly qualified personnel. [ABSTRACT FROM AUTHOR]

Activated sludge process was a low-cost alternative method compared to the conventional physicochemical process for the treatment of heavy metal-containing wastewater. In the present study, the removal efficiency of Pb2+, Cu2+, and Ni2+ from wastewater by a sequencing batch reactor (SBR) activated sludge system was investigated, and the mechanism was revealed by static adsorption experiment of activated sludge. The results showed that the activated sludge in the SBR system was effective in removing Pb2+ and Cu2+ from wastewater at 10 mg·L−1 initial concentration, with a removal efficiency of 83.1 ~ 90.0% for Pb2+ and 74.3 ~ 80.6% for Cu2+, respectively. However, the removal efficiency for Ni2+ was only 0 ~ 6.2%. Static adsorption experiments showed that the adsorption capacity of activated sludge for three heavy metals was shown as Pb2+ > Cu2+ > Ni2+. When the initial concentration was 20 mg·L−1, the equilibrium adsorption capacity of activated sludge for Pb2+, Cu2+, and Ni2+ was 18.35 mg·g−1, 17.06 mg·g−1, and 8.37 mg·g−1, respectively. The main adsorption mechanisms for Pb2+ and Cu2+ were ligand exchange, electrostatic adsorption, and surface organic complexation processes, but Ni2+ removal mechanism mainly included electrostatic adsorption and surface organic complexation processes, showing that Ni2+ removal was inhibited in the presence of Pb2+ and Cu2+. The physicochemical properties and microbial diversity of activated sludge were greatly affected by the heavy metals in the SBR system, and genus Rhodobacter was found to be dominant bacteria enabling resistance to heavy metal ions. [ABSTRACT FROM AUTHOR]

Background: The major aim of the study was to define a scientific framework to evaluate energy recovery from domestic wastewater, based on model assessment of process stoichiometry and kinetics using relevant experimental data. The evaluation was tailored to reveal and explain all the oversights and misconceptions on the subject. A new approach was adopted to focus specifically on a paper by Liang et al. (2022) to better visualize and indicate scientific ways to remedy the key misguidances. The alternative appraisal utilized the latest available support in terms of the database for chemical oxygen demand (COD) fractionation and process kinetics. Results: The evaluation first demonstrated the inherent deficiencies of high rate activated sludge (HRAS) configurations such as the sequencing batch reactor and contact stabilization; then, it presented a new way to define excess sludge components in terms of fractions of the influent COD, indicating the major handicap for energy recovery and biomass loss in the effluent due to gravity settling. Effective energy conservation was computed to remain between 17% and 37% when the sludge age was reduced from 2.0 d down to 0.5 d. Conclusions: The study offered conclusive proof that the contact stabilization process with gravity settling was, in fact, inherently unsuitable for energy conservation. Instead, the emerging scientific approach proposed a single‐volume HRAS system with membrane filtration replacing gravity settling. An equally valid suggestion was to replace anaerobic technology for energy recovery with thermochemical technologies, such as high‐rate pyrolysis, with a much higher energy recovery potential. © 2022 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

BACKGROUND: The performance of microalgal and bacterial systems devoted to wastewater treatment might be limited by the poor settling of microalgal biomass and the inhibition of nitrifying bacteria under high irradiance conditions. This work implemented a photo‐sequencing batch bioreactor (PSBR) treating medium‐ and low‐strength wastewaters. The impact of a short settling time on the formation of microalgal–bacterial aggregates (MABAs) was evaluated. Moreover, online photosynthetically active radiation (PAR) measurements at the bottom of the PSBR were used to identify potential nitrifying activity inhibition. RESULTS: A chemical oxygen demand removal efficiency of up to 88% was obtained for the medium‐ and low‐strength wastewaters. Photoinhibition of the nitrifying activity was observed at PAR values from 73 to 480 μmol m−2 s−1, and it was confirmed under non‐limiting dissolved oxygen conditions. The PSBR operating conditions, including a short settling time (30 min) and treatment of medium‐strength wastewater, favored the rapid formation of MABAs in only 19 days, with a biomass settling velocity (vs) of 0.74 m h−1. The microalgal genera Acutudesmus, Desmodesmus, and Chlorella were predominant in the MABAs. Experimental estimation of the light extinction coefficient (λ = 0.056 m2 g−1 total suspended solids) allowed the simulation of light penetration profiles at different reactor liquid depths and biomass concentrations. CONCLUSION: A short settling time favors the rapid formation of MABAs in PSBR‐type reactors treating medium‐strength wastewater. Online monitoring and simulation of light penetration is a valuable tool to determine photoinhibition of the nitrifying activity in microalgal and bacterial systems. © 2022 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

• An in-depth review of the progress in the aerobic treatment of phenolic wastewater. • Impact of C:N ratio on removal efficiency of MBBR is also reviewed. • MBBR is advantageous over other aerobic systems for the treatment of phenol. • Highlights the significance of integrating biofilm systems within bioreactors for efficient bioremediation. • Removal efficiency is influenced by carrier %, contact area, aeration, and organic loading. Phenol, a toxic and carcinogenic compound found in industrial effluent, poses a severe threat to the environment and aquatic life. Conventional methods such as physio-chemical techniques have limitations in efficiency, cost, and sustainability, leading to the development of advanced hybrid approaches like the Moving Bed Biofilm Reactor (MBBR) to treat phenols. In this study, we aimed at an in-depth review of MBBR for the remediation of phenolic wastewater at an industrial scale. The review uses a methodology that involves a comparative analysis of various conventional methods, including activated sludge process (ASP), sequencing batch biofilm reactor (SBBR), Fluidized Bed Biofilm Rector (FBBR), and trickling filter (TF) with MBBR, to determine their efficacy in phenol degradation. In this context, a thorough bibliometric assay of MBBR is carried out to understand the recent publication trends. The study also examines the impact of different types and shapes of bio-carriers and their filling ratios on phenol biodegradation. The present work demonstrates the feasibility of using an aerobic MBBR along with a Fenton-like system (advanced oxidation processes) to treat phenolic effluent LCCA is discussed for selected treatment methods for assessing the sustainability aspects. In light of recent advancements, future research endeavors should prioritize the refinement and optimization of MBBR systems to strengthen their efficiency and sustainability, thus paving the way for a greener and cleaner future. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Quantitative image analysis was used to estimate EPS fractions and components. • EPS were predicted using partial least squares (PLS) regression. • PLS models for each experimental phase improved the assessment of EPS. • A novel method for EPS quantification was established. Extracellular polymeric substances (EPS) play a vital role in biological wastewater treatment systems. This study investigates the impact of herbicide atrazine (ATZ) on the overall performance, EPS yield, composition, and sludge morphology in an activated sludge (AS) system operated in a sequencing batch reactor (SBR). Since conventional methods for analyzing EPS are time-consuming and releases residues, a new approach was developed in this work to evaluate the EPS fractions and components, based on the morphological characterization of the biomass using quantitative image analysis (QIA) technique coupled with multivariate statistics. Results showed that exposure to ATZ inhibit biomass activity in terms of organic matter (COD) and nitrogen removal. Moreover, both tightly bound EPS (TB-EPS) and loosely bound EPS (LB-EPS) increased under ATZ, indicating that microorganisms release EPS as a defense mechanism against environmental changes. The PN/PS ratio also increases, indicating likely increased hydrophobicity in ATZ phases. Furthermore, ATZ phases exhibit a predominance of large aggregates compared to intermediate and small ones, indicating a change in aggregate morphological structure associated with EPS production. The new approach using QIA coupled with partial least squares (PLS) modeling provides accurate predictions of EPS content. The increase in TB-EPS is closely related to the rise of large aggregates in phases exposed to higher ATZ concentrations. The PLS models demonstrate high accuracy for EPS prediction (coefficients of determination, R2 above 0.86), showcasing the feasibility of using QIA for EPS assessment in AS systems. This approach offers significant potential for regular process monitoring and management, providing a more environmentally friendly methodology by eliminating the need for chemical usage. [ABSTRACT FROM AUTHOR]

One of the factors that has a direct impact on anaerobic digestion is the applied organic loading rate (OLR A). Increasing OLR A can boost methane production but can also cause process failure. As a result, establishing the appropriate OLR A for the procedure is critical. This study evaluated the effect of increasing the OLR A using soybean molasses in a thermophilic anaerobic reactor (R-Thermo), as well as the effect of feeding strategy and co-processing with okara. Furthermore, the performance versus stability trade-off between R-Thermo and mesophilic anaerobic digestion (R-Meso) was investigated. The increase of OLR A from 10 to 15 and 20 kg-COD/m³/d led to a decrease in COD removal efficiency (90, 86, and 75%), methane yield (12.0, 11.6, and 9.9 mol-CH 4 /kg-COD) and an increase in total volatile acids concentration (251, 456, and 1393 mg-HAc/L, respectively). At 15 kg-COD/m³/d, R-Meso performed similarly to R-Thermo, and at 20 kg-COD/m3/d, R-Meso outperformed (81% COD removal efficiency, 9.3 mol-CH 4 /kg-COD rem and 154.5 mol-CH 4 /m3/d). Temperature greatly influenced the distribution of metabolic pathways, as shown by thermodynamic and kinetic analyses, thus impacting bacterial diversity. At 55 °C, amongst the bacterial genera, Tepidiphilus stood out (>28.2%), followed by Acetomicrobium , Coprothermobacter and Candidatus_Caldatribacterium. The OLR A clearly impacted the archaeal community; Methanothermobacter (77.4%) was favored over Methanosarcina (14.8%). Under thermophilic temperature, it seems that syntrophic acetate oxidation (SAO) bacteria might have competed for substrate with acetoclastic methanogens, while in R-Meso microorganisms responsible for the initial steps of organic matter breakdown, such as members of the Firmicutes and Proteobacteria phyla (at least 67%), were dominant. In summary, R-Meso, characterized by a more uniform distribution of metabolic pathways, as well as a diverse and well-adapted microbial consortium, have exhibited enhanced stability and outperformed R-Thermo at high-loads. [Display omitted] • Thermophilic and mesophilic digestion of soybean molasses was compared. • R-Meso and R-Thermo showed similar COD removal and CH 4 production at different loads. • R-Meso digestion resulted in balanced production of intermediate metabolites. • Less diversity in the microbiological consortium present in R-Thermo. • Competitiveness between SAO and acetoclastic methanogens at high temperature. [ABSTRACT FROM AUTHOR]

The impact of a novel sawdust-modified carrier on the performance of aerobic sequencing batch reactor (SBR) was examined. Compared with the conventional polyethylene (PE) carrier, the sawdust-modified carrier had coarse surface and porous side wall, which was beneficial for the rapid formation of biofilm. The biomass of sawdust-modified carrier was 3.4 ± 0.7 times more than those of PE carrier at the end of this study. The biofilm gotten from suspended carrier had higher extracellular polymeric substances (EPS) concentrations than activated sludge (AS). The EPS from biofilm contained higher proportions of polysaccharides compared to those from AS. The SBR with addition of sawdust-modified carrier exhibited higher ammonia nitrogen removal efficiency (84.8%) than the one with addition of conventional PE carrier (73.1%) in a typical cycle at 12 h. The volumetric nitrification rates of modified carrier were higher than those of conventional PE carrier. High throughput sequencing revealed that sawdust-modified carriers exhibited greater microbial richness and diversity compared with traditional PE carriers. Saccharimonadales was the most predominant genus that removed organic matter under aerobic condition, whereas Nitrospira was the dominant nitrifying genus. The present study verifies the advantage of sawdust-modified carrier, which has the potential for the full-scale application in the future. [Display omitted] • A novel sawdust-modified carrier with coarse surface and porous side wall was made. • The biomass of novel carrier was 3.4 ± 0.7 times more than those of PE carrier. • Nitrification rate of novel carrier was 3.16 ± 0.64 times than that of PE carrier. • Novel carrier improved the organic matter removal and nitrification ability of SBR. • Novel carrier had higher microbial richness and diversity than common PE carrier. [ABSTRACT FROM AUTHOR]

Unit energy consumption per kg pollutant removed (kWh/kgCODremoved) is used for the first time in assessing and ranking the sustainability of main treatment technologies of 1215 wastewater treatment plants (WWTPs) in China. The metric better measures the sustainability of main treatment technologies in WWTPs than unit energy consumption per cubic meter treated (kWh/m3). The energy consumption data of these WWTPs were selected from the database of 1399 WWTPs to evaluate the energy efficiency of different treatment technologies. 80.3% of the WWTPs applied anaerobic-oxic plus anaerobic–anoxic–oxic, oxidation ditch, and sequencing batch reactor as main technologies. Statistical analysis shows that the unit energy consumption of WWTPs decreases with increasing design flow rate, operation loading rate, and influent COD concentration. For example, the average unit energy consumption of SBR decreases from 2.76 kWh/kgCODremoved to 0.83 kWh/kgCODremoved when the design flow rate increases from less than 10,000 m3/d to 100,000–200,000 m3/d. The mean unit energy consumption of SBR decreases from 1.71 kWh/kgCODremoved to 1.32 kWh/ kgCODremoved and 2.85 kWh/ kgCODremoved to 0.63 kWh/kgCODremoved as the operation loading rate and COD removal increase from 40% to 100% and from less than 150 mg/L to over 450 mg/L, respectively. SBR has the lowest unit energy consumption among all the technologies. Therefore, SBR might be the most appropriate technology in small and medium-scale WWTPs in China. Regression equations were developed to predict the unit energy consumption for sustainable design treatment trains by input variables such as design flow rate, operation loading rate, and influent COD concentration. [ABSTRACT FROM AUTHOR]

BACKGROUND: Food waste (FW) and waste activated sludge (WAS) are complementary substrates that improve H2 production by dark fermentation. However, there is little experience in the process performance in the long‐term operation of reactors co‐processing FW–WAS. This study aims to determine the optimal FW–WAS ratio in batch H2 production and then feed this FW–WAS ratio to an anaerobic sequencing batch reactor (SBR) to evaluate the influence of three organic loading rates (OLR) – 15, 22 and 45 g volatile solids (VS) L−1 d−1 – on H2 performance and microbial composition. RESULTS: Batch tests showed that the FW–WAS ratio of 90–10 increased 22% of the H2 production compared to the individual FW. In the SBR operation, the OLR significantly influenced H2 performance, reaching the highest productivity of 733 ± 282 mL H2 L−1 d−1 at an OLR of 22 g VS L−1 d−1. The cooperative lactic acid cross‐feeding between Olsenella and Megasphaera resulted in the highest H2 productivity at an OLR of 22 g VS L−1 d−1. OLR promoted the prevalence of different taxa of hydrolytic bacteria, where Enterococcus and Veillonella were positively correlated, with the highest substrate hydrolysis of 50% at an OLR of 15 g VS L−1 d−1. Prevotella, a genus with a wide spectrum of hydrolytic enzymes, was predominant in the SBR operation regardless of the OLR. CONCLUSION: The SBR operation at OLR of 22 g VS L−1 d−1 improved H2 production by applying a 90–10 FW–WAS ratio. The change in OLR promoted different taxa of hydrolytic species in the SBR; however, Prevotella spp. prevailed at the three OLRs. © 2022 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

In this study, alkaline-H2O2 sludge disintegration was combined with anoxic-aerobic sequencing batch reactor (SBR). The carbon obtained by alkaline-H2O2 sludge disintegration was used in the denitrification process and sludge reduction was achieved in the SBR process. In the SBR process, a 9 % increase in nitrogen removal efficiency was achieved with the improvement in the denitrification process. A sludge reduction efficiency of 43 % was obtained in the SBR process with alkaline-H2O2 sludge disintegration. A synergistic effect was obtained in the combination of alkaline and H2O2 methods and the sludge reduction increased by 8 %. By combining sludge disintegration into the SBR process, it is possible to reduce the amount of sludge formed, which is an important environmental problem, and to provide carbon source for the denitrification process. [ABSTRACT FROM AUTHOR]

• Convection-diffusion-reaction system of PDEs models simultaneous sedimentation of solids and reactions with solubles. • Application to sequencing batch reactor for wastewater treatment with fill and draw resulting in moving surface. • Invariant-region-preserving numerical scheme can handle any fill and draw condition. A numerical scheme is proposed for the simulation of reactive settling in sequencing batch reactors (SBRs) in wastewater treatment plants. Reactive settling is the process of sedimentation of flocculated particles (biomass; activated sludge) consisting of several material components that react with substrates dissolved in the fluid. An SBR is operated in cycles of consecutive fill, react, settle, draw, and idle stages, which means that the volume in the tank varies and the surface moves with time. The process is modelled by a system of spatially one-dimensional, nonlinear, strongly degenerate parabolic convection-diffusion-reaction equations. This system is coupled via conditions of mass conservation to transport equations on a half line whose origin is located at a moving boundary and that models the effluent pipe. A finite-difference scheme is proved to satisfy an invariant-region property (in particular, it is positivity preserving) if executed in a simple splitting way. Simulations are presented with a modified variant of the established activated sludge model no. 1 (ASM1). [ABSTRACT FROM AUTHOR]

In this study, removal of both tetracycline (TC) and paracetamol (PCT) were investigated with synthetic wastewater with a sequencing batch reactor. TC and PCT were removed at maximum 62% and 99% under the same conditions which were hydraulic retention time, concentration of dissolved oxygen and acetate concentration, respectively. On the other hand, nitrification and denitrification efficiency were obtained as 95% and 99%. In terms of volumetric removal flux, TC and equivalent O2 flux of TC were calculated as maximum 2.3 and 4.40 mg/L⋅d. Likewise, the maximum removal volumetric flux of PCT and its O2 equivalent flux were determined as 135.9 and 303.1 mg/L⋅d. The results showed that aerobic bacteria preferred PCT rather than TC. [ABSTRACT FROM AUTHOR]

Industrial wastewater discharges often contain high levels of organic matter and nutrients, which can lead to eutrophication and constitute a serious hazard to receiving waters and aquatic life. The purpose of this study was to examine the efficacy of using a sequencing batch reactor (SBR) to treat high-strength organic wastewater for the removal of both chemical oxygen demand (COD) and nutrients (nitrogen and phosphorus). At a constant COD concentration of approximately 1000 mg/L, the effects of cycle time (3 and 9 h) and various C:N:P ratios (100:5:2, 100:5:1, 100:10:1, and 100:10:2) were investigated using four identical SBRs (R1, R2, R3, and R4). According to experimental data, a significant high removal, i.e., 90%, 98.5%, and 84.8%, was observed for COD, NH3-N, and PO43−-P, respectively, when C:N:P was 100:5:1, at a cycle time of 3 h. Additionally, when cycle time was increased to 9 h, the highest levels of COD removal (95.7%), NH3-N removal (99.6%), and PO43−-P removal (90.31%) were accomplished. Also, in order to comprehend the primary impacts and interactions among the various process variables, the data was statistically examined using analysis of variance (ANOVA) at a 95% confidence level, which revealed that the interaction of cycle time and C/N ratio, cycle time and C/P ratio is significant for COD and NH3-N removal. However, the same interaction was found to be insignificant for PO43−-P removal. Sludge volume index (SVI30 and SVI10) and sludge settleability were studied, and the best settling was found in R3 with SVI30 of 55 mL/g after 9 h. Further evidence that flocs were present in reactors came from an average ratio of SVI 30/SVI 10 = 0.70 after 9 h and 0.60 after 3 h. [ABSTRACT FROM AUTHOR]

In the present study, the treatment of slaughterhouse wastewater was carried out in a sequential batch reactor. A lab-scale column type reactor was fabricated with Perspex material having dimensions of 10 cm diameter, 100 cm height, and an effective volume of 7 liters provided with ports at different levels. The reactor performance was evaluated in terms of COD, BOD, TSS, TKN, and phosphorus removal. The reactor was operated for 432 days; the effectiveness of the reactor is the temperature of wastewater in the reactor. The removal efficiencies of COD and BOD were84% and 80% in the reactor. The maximum TSS removal was around 87% and TKN's maximum removal efficiency was 61% in aerobic treatment. Phosphorus maximum removal efficiency was around 68%, in the meantime pH and alkalinity were also monitored, and no change in the pH was reported throughout the experiment. On the other hand, an aerobic SBR is also operated using wastewater after the DAF unit. In the same manner, the reactor was operated with initially diluted wastewater (05 times) and kept HRT 8 h. The reactor performance was studied in terms of COD, BOD, TSS, TKN, and phosphorus. The maximum removal efficiencies of COD and BOD were 80% and 81% respectively. The maximum removal efficiencies of TSS, TKN, and Phosphorus were 73%, 81%, and 69% respectively. It is concluded that the removal efficiency of COD was better in the anaerobic process as compared with the aerobic process in addition the generation of methane gas during the degradation of organic matter can be used for operating the aerobic unit by making some necessary arrangements. Besides this, it is also concluded that the removal efficiency of TKN was better in the aerobic process as compared with the anaerobic process. There was a buildup of VSS from 4500 mg.L-1 to 6500 mg.L-1 in the study. [ABSTRACT FROM AUTHOR]

The use of nitrification inhibition as a concentrating step for ammonium (NH4+), for the purpose of increasing the potential for simultaneous recovery of phosphate (PO43−) and NH4+ from effluent streams of an aerobic sequencing batch reactor (SBR) system, has never been investigated in the literature. Therefore, the present study aimed to determine the effect of the inhibition of nitrification on both the reactor performance and effluent quality in a laboratory scale aerobic SBR system. In order to compare the observed results, a separate reactor, where the inhibition was not applied, was operated as a control reactor (CR) under the identical operational conditions used for the inhibitory reactor (IR). Experimental results for the reactor performance showed that effluents with low total suspended solids (< 50 mg/L) and chemical oxygen demand concentrations (> 90% of removal efficiency based on the influent concentration of 500 mg/L) were achieved for both SBRs by obtaining an activated sludge with a sludge volume index < 60 mL/g after the acclimation period. In the same period, the effluent PO43−, NH4+, and nitrate (NO3−) concentrations were found to be 17.0 ± 4.0, 1.26 ± 0.84, and 21.5 ± 39 mg/L for the CR and 10.0 ± 4.4, 3.9 ± 2.4, and 9.2 ± 1.5 mg/L for the IR, respectively. During this period, 94% of the removed NH4+ (NH4+rem.) was converted to NO3− in the CR, indicating almost complete nitrification occurred in the reactor. However, only 47% of the NH4+rem. was converted to NO3− in the IR as a result of the inhibition of nitrification, meaning a partial inhibition (53%) occurred due to the inhibition treatment. These results clearly demonstrated that the inhibition of nitrification allowed the effluent NH4+ concentrations to increase by suppressing the formation of NO3− ions. Based on the results, it can be concluded that inhibition of nitrification in an aerobic SBR system creates a potential for conserving the effluent NH4+ concentration and increasing consecutive recovery of PO43− together with NH4+ from the effluent discharges. [ABSTRACT FROM AUTHOR]

The discharge of industrial effluent constituting high orthophosphates and organic pollutants in water receiving bodies compromises freshwater quality and perpetuates eutrophication. In this study, an anaerobic–aerobic sequencing batch reactor (SBR) under activated sludge was investigated for orthophosphates and chemical oxygen demand (COD) removal from brewery wastewater. Raw brewery wastewater samples were collected on a daily basis for a period of 4 weeks. The findings of the study are reported based on overall removal efficiencies recording 69% for orthophosphates and 54% for total COD for a sludge retention time (SRT) of 7 days and hydraulic retention time of 18 h at mesophilic temperature conditions of ±25 °C. Moreover, the SBR system showed stability on orthophosphate removal at a SRT ranging from 3 to 7 days with a variation in organic volumetric loading rate ranging from 1.14 to 4.83 kg COD/m3.day. The anaerobic reaction period was experimentally found to be 4 h with the aerobic phase lasting for 14 h. The SBR system demonstrated feasibility on orthophosphates and COD removal with variation in organic loading rate. [ABSTRACT FROM AUTHOR]

The production of highly polluted waste cooking oil (WCO) that contains both inorganic and organic compounds has been increased in Malaysia particularly in food industries. This study was aimed to utilize a sequencing batch reactor (SBR) in order to investigate the aerobic treatment of WCO. The system was operated at pH ranging from 4 to 5 and temperature ranged from 25°C to 31°C. The SBR reactor was fabricated using Perspex with a working volume of 2 L. Experiments were conducted daily at fill, react, settle, draw, and idle phase at 1, 1, 2, 1, and 1 h, respectively. The chemical oxygen demand (COD) and turbidity were assessed in determining SBR performance. Highest COD removal and turbidity values were at 67% and 0.94 NTU, respectively. A stable effluent quality was achieved after 13 d of operational investigation. In general, the SBR treatment was able to achieve acceptable discharge limit for the final treated effluent. [ABSTRACT FROM AUTHOR]

• Convection-diffusion-reaction system of PDEs models simultaneous sedimentation of solids and reactions with solubles. • Application to sequencing batch reactor for wastewater treatment with fill and draw resulting in moving surface. • Simulations of denitrification reactions in vessels with constant or variable cross-sectional area. Reactive settling is the process of sedimentation of small solid particles in a fluid with simultaneous reactions between the components of the solid and liquid phases. This process is important in sequencing batch reactors (SBRs) in wastewater treatment plants. In that application the particles are biomass (bacteria; activated sludge) and the liquid contains substrates (nitrogen, phosphorus) to be removed through reactions with the biomass. The operation of an SBR in cycles of consecutive fill, react, settle, draw, and idle stages is modelled by a system of spatially one-dimensional, nonlinear, strongly degenerate parabolic convection-diffusion-reaction equations. This system is coupled via conditions of mass conservation to transport equations on a half line, whose origin is located at a moving boundary and that model the effluent pipe. An invariant-region-preserving finite difference scheme is used to simulate operating cycles and the denitrification process within an SBR. [ABSTRACT FROM AUTHOR]

This paper deals about an approach to remediation for treating soils and groundwater contaminated with hydrocarbons in a tropical aquifer caused because of leaks from underground tanks in a gas station of Venezuela. Ex situ and in situ remediation treatment options were designed, recommending the ex situ remediation due to microbial inhibition produced by the presence of heavy metals and multiple strata with different soil materials in the interface between the unsaturated and saturated zones, where the most significant hydrocarbon concentrations were found. Under these conditions, ex situ bioremediation option based on two coupled bioreactors can overcome environmental limiting factors by optimizing temperature, oxygen supply, nutrient status, contaminant bioavailability, and microbial population. Ex situ remediation included for soil treatment, a Soil‐Slurry Sequencing Batch Reactor (SS‐SBR) and Upflow Anaerobic Filter separated in three phases (UAF‐3SS). For groundwater treatment SBR‐UAF‐3SS sequence was established. The first phase was represented by SS‐SBR for ex situ bioremediation of soils, configuring COD removal efficiency of 80%. It was set that SS‐SBR performs functions for groundwater treatment operating as SBR, removing 60% COD. For the second phase, an upflow anaerobic filter separate in three phases (UAF‐3SS) designed to ensure 99% COD removal efficiency. [ABSTRACT FROM AUTHOR]

Biodegradation of carbamazepine (CBZ), diclofenac sodium (DCF) and ibuprofen (IBP) was evaluated through fungal granules development in a sequencing batch reactor (SBR). Fungal granules were developed in co-culture of T. polyzona, A. niger, T. longibrachiatum, M. circinelloides and R. microsporus at a retention time (RT) of 2 days and 1 day. Ligninolytic enzymes [laccase (Lac), lignin peroxidase (LiP) and manganese peroxidase (MnP)] were determined. Removal of pharmaceuticals was assessed and metabolites identified using the SPE-UPLC-QToF/MS methods. A pH range of 3–4.6 was found to improve the granulation development from day 6 and the production of ligninolytic enzymes [MnP (253.00 ± 14.19 U/L), Lac (111.58 ± 10.00 U/L) and LiP (95.25 ± 8.22 U/L)]. At steady-state, a removal of 97.41±0.25%, 99.83±0.14%, and 99.91±0.08 were achieved at an RT of 2 days for CBZ, DCF, and IBP, respectively, and of 91.94±0.05%, 99.31±0.12% and 97.72±0.23% at an RT of 1 days for the same PhCs. A variety of chemical reactions have been proposed for degradation pathways catalysed by enzyme-producing fungi, generating fragment ions of intermediate compounds. This study is highly relevant for cost-effective and environmentally friendly wastewater treatment processes in water scare countries. [ABSTRACT FROM AUTHOR]

In this study, the behaviors of amoxicillin and ciprofloxacin were investigated in the conventional treatment systems in both theoretical and experimental manner. The doses of these pharmaceuticals which inhibit the treatment were determined. The efficiencies of amoxicillin and ciprofloxacin in response to dose increments were determined by monitorization of chemical oxidation demand parameter. Based on the results of these studies, amoxicillin doses >35 mg/L and ciprofloxacin doses >10 mg/L reduced treatment efficiency by leading changes in the structure of activated sludge. The sludge became sticky and dark due to the increase in the extracellular polymeric substance formation in the bacteria with increasing pharmaceutical concentration. The highest and lowest removal efficiencies were found as 39.8 and 14.9% for amoxicillin doses of 5 and 20 mg/L, respectively. The greatest part of the removal efficiency was achieved through adsorption in the sludge (33.8%). On the other hand, the highest and lowest removal efficiencies were found as 15.17 and 2.85% for ciprofloxacin doses of 30 and 75 mg/L, respectively. Again, the greatest part of the removal efficiency was achieved through adsorption in the sludge (11.83%). This indicates that removal mechanisms for both pharmaceuticals were sludge adsorption as amoxicillin and ciprofloxacin biodegradations were low at all doses investigated. To compare experimental data with theoretical estimations, pharmaceutical removal was calculated in Sewage Treatment Plant (STP) using EPI Suite program. According to experimental results, the total removal efficiencies were consistent with theoretical estimations calculated by Environmental Protection Agency (EPA) Draft Method. There may be inconsistency between theoretical estimations and experimental results due to differences in experimental conditions caused by microbiological behaviors in the theoretical conditions. The removal efficiencies for amoxicillin and ciprofloxacin calculated by default method were lower than those calculated by EPA draft method since biodegradability is not taken into consideration in the default method. [ABSTRACT FROM AUTHOR]

This paper deals with the calibration of the model for the utilization rate of organic and nitrogenated substrates (URONS) by the microorganisms in a sequencing batch reactor. The URONS model parameterization was carried out using data obtained from two experimental designs (EDs) applied on tannery wastewater (TW), which included as factors: First ED (aeration sequence and cycle duration) reached a COD removal efficiency (RE) between 29% (cycle duration of 6 h) and 48% (cycle duration of 24 h). Second ED (aeration sequence and filling time) obtained COD‐RE (47–51%), NH4‐N–RE (71–91%), and TKN‐RE (50–67%). The URONS model was based on Monod's equation modification. For the first ED, the results of the maximum URONS parameter (rsm)$({{r_{{\rm{sm}}}}})$ of 135–946 mg/L·h suggest the organic substrate accumulation due to a possible inhibition of the microorganisms by TW substances such as heavy metals and metal halides. For the second ED, the rsm${r_{sm}}$ parameter values resulted negative and varying in the order of −10−2 to −10−4 mg/L·h with respect to (rsm)$({{r_{sm}}})$ for the first ED indicating that a better microorganism performance for URONS occurred in the second ED. For both EDs, the saturation parameter (Ks)$({{K_s}})$ values compared to the effluent substrate concentration suggest that the primary substrate for biodegradation was present in the TW. [ABSTRACT FROM AUTHOR]

Most synthetic dyes are toxic and hardly biodegradable compounds that enter the environment mainly through the discharged of non-treated textile industry effluents. The present study investigated the removal of the textile monoazo dye Reactive Red 198 (RR-198) from aqueous solutions using the ultraviolet light and ozonation alone and in combination (i.e., UV/O3) followed by a Sequencing Batch Reactor (SBR). The pH (5 ≤ pH ≤ 9) and dye initial concentration (50–300 mg/L) parameters were optimized in the ozonation process at reaction time of 0–60 min. Then, TOC removal and dye discoloration percentage was compared with the O3, UV and O3/UV processes. In order to compare the performance of the SBR in dye discoloration of RR-198 and TOC removal, four types of effluent, including Raw dye, O3-pretreated dye, UV-treated dye and UV/O3-pretreated dye were separately treated in the SBR system. In the ozonation process, by increasing the pH and reducing the initial dye concentration increased the discoloration percentage. The highest dye discoloration percentage and TOC removal obtained in the hybrid UV/O3/SBR process. Combining biological systems and Advanced Oxidation Processes is an appropriate option for the decomposition of resistant pollutants and increasing the biodegradability of these compounds and is applicable in the water and wastewater industry. [ABSTRACT FROM AUTHOR]

Biological nitrogen and phosphorus removal often requires an external carbon source to be effective during wastewater treatments. The purpose of this work was to evaluate a sequencing batch reactor (SBR) operated in a non-conventional anoxic/aerated (An/O) regime (alternated condition) treating synthetic wastewater simulating secondary anaerobic effluent mainly composed by P-phosphate and N-nitrate. The focus was to report the achieved biological efficiency removal of phosphorus and nitrate from the synthetic inlet when adding pre-fermented glycerol as the sole external carbon source. Experimental phase I aimed at the glycerol fermentation in batch reactors, leading to the formation of ethanol and volatile fatty acids. During experimental phase II, a non-acclimated (C1) and an acclimated biomass (C2) were used as inoculum of the SBR operated in the (An/O) regime. The anoxic phase was set to couple denitrification and P-release/uptake. The aerated phase was set to remove any remaining phosphorus. The fermented glycerol was applied in 15 gCOD g−1 N-NO3− and 29 gCOD g−1P-PO4−3 ratios in a sequential batch reactor during a non-aerated phase. This operation favored the development and maintenance of phosphorus-accumulating organisms (PAO), as well as denitrifying organisms, resulting in approximately 90 ± 11% and 98 ± 3% for phosphorus and nitrogen removal, respectively. The study showed that the fermented glycerol can be successfully applied as an electron donor for biological nitrogen and phosphorus removal during wastewater treatments. [ABSTRACT FROM AUTHOR]

The transient chlorophenol shock under some emergency conditions might directly affect the pollutant removal of bioreactor. Therefore, the recovery of bioreactor performance after transient chlorophenol shock is a noteworthy issue. In the present research, the performance, antioxidant response, microbial succession and functional genes of sequencing batch reactor (SBR) were evaluated under transient 2,4,6-trichlorophenol (2,4,6-TCP) shock. The chemical oxygen demand (COD) and ammonia nitrogen (NH 4 +-N) removal efficiencies decreased sharply in the first 4 days after 60 mg/L 2,4,6-TCP shock for 24 h and gradually recovered to normal in the subsequent 8 days. The nitrogen removal rates and their corresponding enzymatic activities rapidly decreased after transient 2,4,6-TCP shock and then gradually increased to normal. The increase of antioxidant enzymatic activity, Cu-Zn SOD genes and Fe-Mn SOD genes contributed to the recovery of SBR performance. The abundance of genes encoding ammonia monooxygenase and hydroxylamine dehydrogenase decreased after transient 2,4,6-TCP shock, including amoA , amoC and nxrA. Thauera , Dechloromonas and Candidatus_Competibacter played key roles in the restorative process, which provided stable abundances of narG, norB , norC and nosZ. The results will deeply understand into the effect of transient 2,4,6-TCP shock on bioreactor performance and provide theoretical basis to build promising recoveries strategy of bioreactor performance. [Display omitted] • Nitrogen removal rate sharply reduced after transient 2,4,6-trichlorophenol shock. • Transient 2,4,6-trichlorophenol shock promoted reactive oxygen species production. • The increase of genes SOD1 and SOD2 abundance could resist the peroxidation. • Transient 2,4,6-trichlorophenol shock reduced genes amoA , amoC and nxrA abundance. • Functional gene contribution shifted under transient 2,4,6- trichlorophenol shock. [ABSTRACT FROM AUTHOR]

In this study, by inoculating 65% activated sludge and 35% intact aerobic granular sludge (AGS), the rapid granulation of AGS was achieved to treat automobile coating wastewater (ACW). The results showed that after 15 d of operation, compact AGS which a clear shape was found in the sequencing batch reactor with the sludge volume index is 31 mL/g, and an average particle size of 1.2 mm. When the reactor was operated for about 50 d, the chemical oxygen demand, total nitrogen, total phosphorus, and phenol could be effectively removed from the ACW by AGS, with removal rates of 85%, 82%, 62%, and 90%, respectively. Furthermore, the microbial community dynamics were studied by high-throughput sequencing. The correlation between the pollutant removal efficiency and the level of the microbial community (phylum, class, order, family, and genus) was investigated. The results showed that the most abundant genus Thauera played an important role in phenol degradation. Moreover, the abundances of Zoogloea, Azoarcus, Stenotrophomonas, Sediminibacterium, Methyloversatilis, and Acidovorax gradually increased. These functional genera had a significant effect on the biodegradation of phenol and organic matter. This research provides new insights into the rapid start-up of AGS bioreactors and illustrates the practical application potential of AGS technology in the treatment of phenol-containing ACW. [ABSTRACT FROM AUTHOR]

Hospital wastewater consists of various pharmaceutical compounds. If a proper treatment procedure is not considered, discharging these compounds into the environment can cause serious problems in the aqueous ecosystem, as well as those connected to humans wellbeing. This study aimed to remove ranitidine and cefixime trihydrate drugs simultaneously using adapted activated sludge in a sequencing batch reactor (SBR) and to monitor each drug degradation separately by means of statistical analysis using MATLAB 8.1 software. Total nitrogen, total phosphorus, and chemical oxygen demand analyses were conducted; furthermore, the spectrophotometric spectrum of the solution was recorded as well. The partial least squares analytical method using MATLAB 8.1 software was utilized to analyze the results with the obtained R2 value of 0.99 for both ranitidine and cefixime. 71.67% of ranitidine and 59.67% of cefixime trihydrate were removed during the biological treatment in the SBR. [ABSTRACT FROM AUTHOR]

Aerobic granular sludge (AGS) has been considered a breakthrough in the wastewater treatment sector given its key characteristics, such as excellent settleability, simultaneous removal of organic and nutrient pollutants, and compactness. However, the formation of granules often delays the start‐up of granular‐based systems, especially in large‐scale settings. This study addressed the start‐up of a pilot‐scale AGS sequencing batch reactor (SBR) treating domestic sewage, monitored for over 280 days. The challenges faced during aerobic granulation using a mixture of activated sludge and anaerobic granular sludge as inoculum and the performance of the reactor on organic matter, nitrogen, and phosphorus removal were discussed. Results showed that robust and stable granules were formed after an initial period of around six months, with the settling time playing a key role on granules development. At least 80% of granules had a diameter greater than 0.2 mm and 60% >1 mm. In general, the reactor achieved high nitrogen removal efficiency, as well as satisfactory removal of soluble COD. However, total COD abatement was impaired by the various episodes of suspended solids loss with the effluent. Overall, this study demonstrated that the reactor was efficient in the treatment of domestic sewage, but its performance was adversely affected from sudden changes in the influent quality. Practitioner points: Aerobic granular sludge (AGS) applied to small‐scale domestic sewage treatment.The control of sludge age in AGS can be a problem due to short sedimentation times.High DO to maintain aerobic granulation can economically make the process economically unfeasible in tropical countries.A sludge with excellent sedimentation properties was obtained. However, maintaining the granule over time is a challenge. [ABSTRACT FROM AUTHOR]

Steroid estrogens are emerging environmental contaminants that have been frequently detected in the effluent of wastewater treatment plants, posing potential threats to the aquatic ecosystem and human health. In this study, the effect of different influent carbon to nitrogen (C/N) ratios (2, 5, 8, 11) on estrogens removal was investigated in sequencing batch reactors. In addition, microbial diversity, community structure and functional microbes in activated sludge were analyzed by MiSeq high-throughput sequencing. The results indicated that the removal efficiency of chemical oxygen demand risen with the increase of C/N ratios, and the values of effluent NH4 +-N and NO2--N improved, but the values of effluent NO3--N reduced with the increase of C/N ratios. The removal efficiency of estrone (E1) and 17ß-estradiol (E2) was both far higher than that of 17a-ethinylestradiol (EE2) regardless of influent C/N ratios. The removal efficiency of EE2 gradually enhanced with the rise of C/N, and only reached 75.69% when the C/N ratio was 8. The microbial richness in sequencing batch reactors (SBRs) with C/N ratios of 5 and 8 was higher than that of SBRs with C/N ratios of 2 and 11 but had a rather lower proportion of dominant microorganisms. Illumina sequencing showed that Thauera, Tetrasphaera, Tessaracoccus became dominant genera in four reactors, and the kinds of functional bacteria followed the order of E2 > E1 > EE2. It is likely to produce the stronger synergistic elimination of estrogens by heterotrophic and autotrophic bacteria when the C/N ratio was 8. The study promotes an understanding of the impacts of influent C/N ratios on bacterial communities and estrogens removal in SBR. [ABSTRACT FROM AUTHOR]

Single‐stage partial nitration and anammox (PN/A) process was achieved in a sequencing batch reactor (SBR) using a submerged dynamic membrane (DM) in this study. The reactor was stably operated for 200 days, and the nitrogen removal efficiency (NRE) was sustained at 70.3 ± 7.2% at a nitrogen loading rate (NLR) ranging from 0.1 to 0.3 kgNm−3 day−1 with a hydraulic retention time (HRT) of 24 hr. When the NLR was 0.2 kgN m−3day−1, the NRE achieved was high as 80% with a low concentration of dissolved oxygen (DO) of 0.13 mg/L. In addition, the specific activity of anammox bacteria and ammonia‐oxidizing bacteria (AOB) reached was 2.72 and 16.80 gN gVSS−1day−1, respectively. The DM intercepted the biomass due to the lamellar, intact, dense biofilm self‐generated on the surface of the supporting material, which had an effluent turbidity of 10 NTU. The enriched anammox functional bacteria were Candidatus Jettenia (11.06%) and the AOB‐like functional bacteria consisted primarily of Nitrosomonas, with a relative abundance of 2.76%, which ensured the PN/A process proceeding. This study provides a novel reactor configuration of the single‐stage PN/A process in the view of practical applications. Practitioner points: Single‐stage partial nitration and anammox (PN/A) process was achieved using a submerged dynamic membrane (DM) in this study.The reactor was stably operated for 200 days, and the nitrogen removal efficiency was sustained at 70.3 ± 7.2%.The feasibility of the PN/A system with DM is evaluated.The main objective is to provide a control strategy of the DM‐SBRs for practical applications. [ABSTRACT FROM AUTHOR]

Several tannery effluent treatments were studied, but there was no process that could remove the total pollution of these effluents. Besides, most of those processes are expensive. In this study, a promising coupled treatment of tannery effluents was performed to eliminate the entire pollution load of these toxic effluents. The treatment of these effluents was by precipitation using ferric chloride coupling with the sequencing batch reactor (SBR) process. For the SBR system, a daily cycle treatment and a high organic load of 1.5 kg of COD d-1 m-3 were used. Concerning the results, this combined system provided very satisfactory outcomes, wherein removals were 99.89%, 99.98%, and 99.99%, respectively, for the chemical oxygen demand (COD), the sulfide ions, and the total chromium. Thus, the treated effluent is strongly conformed to the Moroccan standard of discharge. This result was not reached when these two systems were applied separately in previous studies. Therefore, this combined treatment can be an attractive and economic treatment for tannery effluent treatmen [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the effects of increasing salinity on the performance and microbial community structure in a sequencing batch reactor (SBR) treating low C/N ratio wastewater. The SBR was subjected to a gradual increased salinity from 0 wt% to3.0 wt% under low Chemical Oxygen Demand (COD)/N ratio, operating for 80 days. The study results indicated that high salinity decreased the removal efficiency of ammonium ( NH 4 + - N ) from 77.09% (1.0 wt%) to 45.7% (3.0wt%). The organic matter removal are not significantly affected by the high salinity. Non-metric Multi-Dimensional Scaling (NMDS) analysis showed that the gradual increased salinity altered the overall bacterial community structure, and low salinity (1wt%) promoted the bacterial diversity, while high salinity (2 and 3 wt%) significantly decreased the bacterial diversity in low C/N ratio activated sludge system. Further analysis revealed that two genera related to nitrification process (unclassified-Nitrosomonadales and g-Nitrospira) were inhibited, while a genus related to organic removal (Piscicoccus) and three genera related to denitrification (Rodobacteraceae, Denitromonas and Hyphomicrobium) increased significantly at a salinity of 3 wt%. This study provides insights of shifts in the bacteria community under the stress of high salinity in low C/N ratio of activated sludge systems. [ABSTRACT FROM AUTHOR]

Copyright of Revista Ambiente e Água is the property of Revista Ambiente e Agua 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 basic design principles of a sequencing batch reactor (SBR), subject to seasonal wastewater flow fluctuations. Emphasis was placed upon highlighting the role of major process parameters, namely the cycle time, fill volume, number of reactors, the stationary volume, which holds the settled biomass and finally the sludge age in optimizing the necessary SBR configuration, which will effectively serve under these fluctuations. For this purpose, two sites with different wastewater generation schemes were selected in Erbil, a city in northern Iraq. The first one was a residential unit and the second, a luxury hotel with 250 rooms and a full capacity of 500 guests, which was attained in the summer period. The basic approach for SBR design for organic carbon chemical oxygen demand (COD) removal was summarized in the study. While the necessary methodology looks simply, it requires a detailed wastewater characterization involving the assessment of volatile and fixed solids components and COD fractionation. The adopted approach also relies on correlations between major parameters and process kinetics and stoichiometry. System optimization against seasonal fluctuations was essentially based on the utilization of spare reactor volume created under low wastewater flow conditions, without changing the selected parallel reactors, to increase the sludge age to the extent possible, which resulted in minimizing the excess sludge generation. [ABSTRACT FROM AUTHOR]

A novel biological phosphorus removal in anoxic–aerobic sequencing batch reactor (SBR) using starch as carbon source had been found, but the role played by nitrate in this process was not clear yet. To reveal the effect of nitrate, two laboratory-scale SBRs operated in alternating anoxic–aerobic (R1) and alternating anaerobic–aerobic (R2) modes, respectively, were applied in this study. Results showed that phosphorus removal efficiency reached 78% and 77%, respectively, in R1 and R2. During anoxic stage in the R1, the accumulation of lactic acid was 16.66 mg/L, which was higher compared with 2.22 mg/L in the R2. While volatile fatty acid (VFA) was detected in the R2 with 20.44 mg/L, it indicated that there was more than one way for fermentation of starch in the two systems. Moreover, the production and consumption concentration of glycogen (74.29 mg/g volatile suspend solid (VSS) and 72.54 mg/g VSS) of the R1 was lower compared with 92.64 mg/g VSS and 105.75 mg/g VSS in the R2, respectively. It suggested that the internal carbon source of phosphorus absorption mainly derived from the decomposition of glycogen in the R2, and phosphorus uptake efficiency was related to the consumption of glycogen. The different bacterial community structure of the two systems was detected by high-throughput determination. Lactic acid-producing bacteria, such as Saccharibacteria genera incertae sedis and Enterobacter were predominated of the R1, whereas Thiothrix, Thermomonas, and Chryseolinea were dominant in the R2. It demonstrated that nitrate was more conducive to the enrichment of lactic acid-producing bacteria, thus promoting phosphorus uptake. This study improved our understanding of phosphorus removal by fermenting bacteria. [ABSTRACT FROM AUTHOR]