The study evaluated the most efficient biological nitrogen removal (BNR) process in four full-scale municipal wastewater treatment plants (WWTPs) by using BioWin, a simulation software based on the ...activated sludge model (ASM). A series of experiments were conducted to determine the kinetic and stoichiometric parameters for the ASM. Results indicated that autotrophic maximum specific growth rates in the studied WWTPs were generally higher compared to previous findings, likely due to their low COD/N ratios, emphasizing the importance of local parameterization. Continuous water quality monitoring in each plant was employed to validate the model. Dynamic simulation results indicated that the error remained within an acceptable range, with a mean relative error of less than 20%, confirming the reliability of ASM parameters derived from batch experiments. Subsequently, various operational scenarios were analyzed to determine the optimal BNR process for each plant, considering influent flow rate, internal recycling, and methanol addition. Simulation outcomes suggested that O/A (oxic/anoxic) operation is preferable for plants with low organic content (COD = 60–110 mg/L), considering both operational costs and total nitrogen removal rate. Conversely, A/O (anoxic/oxic) operation might be advantageous for plants with higher influent organic matter (COD = 200 mg/L).
Display omitted
•ASM-based simulations were conducted for four full-scale WWTPs.•Obtaining local values for kinetic and stoichiometric parameters is crucial.•The COD/N ratio may significantly influence the autotrophic growth rate.•The choice between the A/O or O/A process primarily depends on the COD/N ratio.•Response surface modeling based on simulation scenarios is effective for optimization.
Improvement of current wastewater treatment plants (WWTPs) to accommodate the growing influent flow rate and cope with the increasingly stringent regulations is hindered by the allowed space and the ...difficulty of changing the design parameters. Mathematical modeling is a useful tool for assessing the performance of WWTPs in light of broadening objectives. We herein explore the utilization of mathematical modeling to improve effluent quality in conventional activated sludge systems. BioWin was used to model Mansoura WWTP, one of the largest WWTPs in Egypt. Lab records, design reports, and additional analyses were conducted through site visits and a comprehensive sampling campaign. The wastewater was characterized, and the plant-wide model was calibrated following the protocol of the Dutch Foundation for Applied Water Research STOWA. Important kinetic and stoichiometric parameters were identified and adjusted during the calibration process. The model validity was assessed using different validation periods considering average relative deviation (ARD) values below 20 % as acceptable. The optimized nitrification and denitrification processes involved 16 scenarios with different operational conditions. By changing some zones in the aeration basin from aerobic to anoxic and increasing the return activated sludge, the average ammonia and nitrate concentrations were significantly reduced from 23.06 and 0.5 mg/L to 4.64 and 0.07 mg/L respectively. Furthermore, phosphorus removal optimization was carried out through biological and chemical processes. Chemical phosphorus removal was 85.76 % by using a coagulant dosage of 25 mg/L, resulting in an effluent concentration of 1.04 mg P/L. Biological phosphorus removal was increased to 85.43 % by modifying the volume of anaerobic and aerobic zones with lower power consumption. Overall, this study demonstrates the effectiveness of mathematical modeling in enhancing effluent quality and reducing energy consumption to meet stringent wastewater treatment regulations.
Display omitted
•Mathematical modeling was used to study different scenarios of WWTPs improvement.•16 Scenarios for improvement of Mansoura WWTP were evaluated.•The improvement includes COD, nitrogen, and phosphorus removal.•The model was validated by the average relative deviation.
In this study the experimental data on the biodegradation of 16 pharmaceuticals in activated sludge were reviewed and also the theoretical biodegradation of these pharmaceuticals was calculated using ...BIOWIN models. The main aim was to show the similarities or discrepancies between the two. Experimental data were critically reviewed considering biodegradation rates, biodegradation mechanisms and biosorption of pharmaceuticals. For some pharmaceuticals, theoretical BIOWIN estimations and experimental findings deviated from each other. For example, if only BIOWIN estimations are considered, clarithromycin, azithromycin and ofloxacin would be defined as refractory. However, in experimental studies, they appeared to be not completely refractory. One of the reasons is that in most cases pharmaceuticals could be used as secondary substrates in the presence of sufficient bulk organic matter. In addition, all experimental studies indicate that at long Solids Retention Times (SRTs), nitrification activity becomes enhanced and the enzyme AMO leads to the cometabolic elimination of many pharmaceuticals. BIOWIN models prove to be very helpful for having an initial idea about biodegradability of pharmaceuticals. However, in order to estimate the biodegradability under real conditions, the models can be extended to include the different removal mechanisms reported in this study.
Display omitted
•Biodegradation of 16 pharmaceuticals in experimental studies was reviewed.•Biodegradability of pharmaceuticals was estimated with BIOWIN models.•Theoretical BIOWIN estimations and experimental results were compared.•BIOWIN could be used for having an initial idea about biodegradability.•Nitrification activity and longer SRTs enhanced the removal of pharmaceuticals.
Three different innovative mathematical models were established to assess the volumetric nitrogen conversion rates of a lab-scale ANAMMOX upflow anaerobic sludge blanket reactor. Despite the vast ...technological and economical advantages of ANAMMOX, major challenges in process implementation call for mathematic simulations of the process, optimization of operating conditions, and kinetic/statistical analysis of the entire process. In this study, all developed mathematical models implemented via BioWin®, were calibrated and validated, with adequate representations of a bench-scale micro-granular ANAMMOX process, to understand the potential setbacks of ANAMMOX process start-up and stabilization. Fundamental calculations of the kinetic and stoichiometric constants were integrated in the BioWin® software, and the adjusted parameters based on experimental analysis were applied for the assessments. Based on the results from the statistical approach, one of the models (Model III) exhibited a precise prognosis of the effluent data for the entire operational phases with a mean relative error (MRE) of approximately 1.96, 4.36 and 2.54% for nitrogen removal efficiency, removal rate and loading rate, respectively. Evaluating alkalinity and pH during the operation, led to identifying an acceptable fit between the experiment and Model III results, with a MRE of −7.19 and −0.35%, correspondingly. This study confirms the reliability of ANAMMOX-based process modeling and high predictive ability with BioWin®. The presented simulation constants and modeling outline, can be further employed in full-scale applications design and development.
Display omitted
•A mathematical model using BioWin describing anammox in a UASB reactor was developed.•The calibrated model was capable of predicting the regular effluent data precisely.•Three significant testing methods confirmed the models accuracy.•BioWin software is a reliable modeling tool for anammox-based processes.
In recent years, Moving Bed Biofilm Reactors (MBBRs) have been preferred to conventional processes with suspended biomass. The main reason for this preference is that it can achieve better removal ...efficiencies than conventional systems with smaller footprints. However, unlocking the full potential of MBBRs in large-scale WWTPs remains challenging in real life. In this study, the performance of three different treatment technologies, Extended Aeration Activated Sludge (EAAS), Hybrid Fixed Bed Biofilm Reactor (HFBBR), and Hybrid Moving Bed Biofilm Reactor (HMBBR), was investigated over a year in a WWTP located in El-Gouna, Egypt. The COD removal efficiencies of the three systems were comparable, with the EAAS achieving 93.5%, HFBBR 94%, and HMBRR 95%. Nevertheless, the NH4 removal efficiency of the EAAS was slightly lower (97.5%) than that of the HFBBR and the HMBBR, that achieved a removal efficiency of 98%. BioWin Software was able to mimic the real case of the WWTP of El-Gouna and critically defined all plant limitations and operational data. Different simulations were modeled to test the hydraulic and organic loading capacities of the three systems under different scenarios and operating conditions. The HMBBR system failed to withstand the increase in organic load because of the biomass sloughing effect and subsequently high TSS loads in the settlers. Biomass sloughing overloaded the settlers and lead to biomass loss in the effluent. As the settleability of the HMBBR sludge was significantly lower than for the HFBBR the TSS loss in the effluent happened that much earlier that the moving carrier application had an adverse effect contradicting with the primary purpose of adding media carriers. Model simulations and data analysis findings were used to recommend the most suitable configuration for upgrading an existing system using the attached growth technique with all kinetic parameters and operational conditions. The recommended configuration focuses mainly on the separation of plastic media in a compartment with a very low hydraulic retention time to absorb the incoming shock load.
Display omitted
•Bioreactors show similar chemical oxygen demand and NH4 removal in El Gouna WWTP.•BioWin 6.2 aids in WWTP upgrading by simulating processes.•The biofilm carriers may experience sloughing under high organic loads.•Changing the location of biofilm carriers in WWTP would enhance the plant performance.
Although biodegradation of organic matter is well-known to trigger enrichment of arsenic (As) in groundwater, the effects of DOM sources and biodegradability on As enrichment remain elusive. In this ...study, groundwater samples were collected from the Hetao basin to identify DOM source and evaluate biodegradability by using spectral and molecular techniques. Results showed that in the alluvial fan, DOM was mainly sourced from terrestrially derived OM, while DOM in the flat plain was more originated from microbially derived OM. Compared to terrestrially derived DOMs, microbially derived DOMs in groundwater, which had relatively higher H/Cwa ratios, NOSC values and more biodegradable molecules, exhibited higher biodegradability. In the flat plain, microbially derived DOMs with higher biodegradability encountered stronger biodegradation, facilitating the reductive dissolution of Fe(III)/Mn oxides and As enrichment in groundwater. Moreover, the enrichment of As depended on the biodegradable molecules that was preferentially utilized for primary biodegradation. Our study highlights that the enrichment of dissolved As in the aquifers was closely associated with microbially derived DOM with high biodegradability and high ability for primary biodegradation.
Display omitted
•Groundwater DOM was mainly sourced from terrestrially derived OM in the alluvial fan.•Groundwater DOM was more originated from microbially derived OM in the flat plain.•Microbially-derived DOMs had high H/C, NOSC values, and more biodegradable molecules.•Microbially-derived DOM encountered strong biodegradation, promoting As enrichment.•As enrichment depended on DOM molecules being prone to primary biodegradation.
Acid phase digestion pretreatment resulted in an increase in biogas production and volatile solids (VS) removal at the West Camden plant which was fed with only waste activated sludge. Without the ...acid phase digesters, the specific methane yield of waste activated sludge (WAS) was 190 L/kgVSadded, whereas a specific methane yield of WAS of 231 L/kg VSadded was observed from sludge sampled from the acid phase digester. The specific methane yield obtained from BioWin® simulation was 331 L/kgVSadded and was slightly higher than that from BMP assessment (231 L/kgVSadded). In addition, the overall VS removal values obtained from BioWin® simulation (44%) and biomethane potential (BMP) evaluation (49%) were close to the actual VS removal value (45%) achieved by the plant. The consistency between full scale evaluation data, BioWin® simulation, and BMP assessment suggests that BioWin® simulation and BMP study can be used to guide future design and optimisation of acid phase digestion pretreatment to intensify anaerobic digestion of sewage sludge.
Display omitted
•Acid phase digestion of waste activated sludge as the only substrate was evaluated.•Acid phase digestion could facilitate anaerobic digestion at a high organic loading.•Results from BioWin® and BMP assessment are consistent with full scale evaluation.•BioWin® and BMP are effective tools to predict process performance.
Pilot scale experiments, biomethane potential (BMP) evaluation, and BioWin simulations were conducted to evaluate the intermittent co-digestion of sewage sludge and crude glycerol for on-demand ...biogas production. BMP tests revealed that both pure and crude glycerols were readily biodegradable. BioWin simulations showed that intermittent glycerol injection at a high (3% v/v) dose might lead to an increase in chemical oxygen demand of the digestate. Results from the pilot scale experiments confirmed that intermittent injection of crude glycerol at both low (0.63% v/v) and high (3%v/v) doses could be used for on-demand biogas production to match the daily fluctuation in energy consumption at a typical wastewater treatment plant. However, in terms of additional biogas production per volume of added glycerol, the lower dose (0.63% v/v) was more effective. The additional methane yield (at the glycerol dose of 0.63% v/v) was 1.3 m3 per litre of crude glycerol. This value obtained from the pilot scale experiment was higher than that from the BMP test but lower compared to that predicted from the BioWin simulation.
•Crude glycerol was as readily biodegradable as pure glycerol.•Glycerol addition to sewage sludge at low doses did not cause any negative impact.•Intermittent glycerol addition could be used for on-demand biogas production.•The findings were confirmed with BioWin simulation and pilot experiments.
Organic acid digesters are reactors of growing interest for municipal nutrient recovery technologies, but the industry standard BioWin modeling software does not accurately predict their performance. ...A BioWin configuration using default parameters will over-predict volatile fatty acid production in an acid digester, yielding an unrealistically low pH. We have characterized the effects of parameters for local pH inhibition thresholds, growth and decay kinetics, and hydraulic residence times to successfully facilitate more accurate modeling of acid phase digestion reactors in BioWin. These changes show improvements in a range of treatment train models without affecting accuracy in other reactors. Results were calibrated against a municipal acid phase digester to accurately predict pH, VFA concentration, and gas production. In particular, an acid digester with a measured suspension pH of 5.14 was predicted by BioWin using default parameters to exist at pH 4.35 with highly sensitive biogas methane content, but our parameter changes were able to correct the predicted suspension pH and VFA concentrations over a range of values. We also demonstrate that several intuitive or traditional parameters a BioWin user may attempt, such as growth and fermentation kinetics, do not yield meaningful results. Refinements incorporated into BioWin should allow future operators to easily model acid digesters for their specific treatment trains or allow users to predict changes while testing new wastewater treatment technologies.
•BioWin default parameters overpredict acidic conditions for acid digesters.•Key parameter changes convert default digester process to dedicated acidogenic process.•First published demonstration of a technique to correct the behavior holistically•Calibrated using sampling data from a full-scale municipal acidogenic digester•Technique demonstrated on multiple configurations including BioWin cabinet models
•Successful plant-wide modelling for a large-scale WWTP was achieved.•The stoichiometric and kinetic parameters for the BioWin model were predicted.•The predicted parameters correlate significantly ...with historical results.•Nitrification and denitrification were optimized with no modifications in the WWTP.
In this paper, a plant-wide model has been created for an Egyptian WWTP located in Cairo, namely the Gabal El-Asfar, using BioWin 5.3 software. The model has been created according to the Good Modeling Practice protocol where design reports, effluent analysis, and historical data have been collected - along with various site visits and a detailed sampling campaign. The collected data was used to acquire the necessary analysis for wastewater characterization and model calibration. The wastewater has been characterized and the model has been calibrated according to STOWA protocol for calibration. Then, the model has been dynamically validated using the analysis acquired over an entire year. The model’s accuracy was acceptable and therefore was created to perform optimization studies. Multiple operational scenarios were simulated to achieve the highest effluent quality with nitrogen removal, as the plant currently is not able to perform nitrification-denitrification. Different DO concentrations, RAS flows, SRTs and consequently WAS flows were varied to optimize the nitrogen removal. It was found that nitrification and denitrification percentages of 94 and 62.4%, respectively, could be achieved easily without modifying the WWTP’s configuration or unit capacities. This was achieved by increasing the SRT from 2.7 to 7 days, while converting some compartments of the aeration tank from aerobic to anoxic. Sludge and water lines were both included in to assess the effect of any change in the operating conditions on all components of the plant including sludge units.
PDF
