Systematic Modeling of Municipal Wastewater Activated Sludge Process and Treatment Plant Capacity Analysis Using GPS-X

Integrated environmental management and GPS-X modelling for current and future sustainable wastewater treatment: A case study from the Middle East

In the context of today's rapidly changing environmental challenges, accurately predicting the performance and efficiency of environmental management strategies is crucial. Particularly in the Middle East, where research on wastewater treatment plants (WWTPs) is notably lacking, addressing this need is imperative. This study investigates the treatment efficiency of a wastewater treatment plant and proposes various techniques to enhance its performance. Employing a case study method, we utilise the GPS-X model to forecast the plant's performance under diverse scenarios, offering solutions for future challenges. The results reveal that the current plant layout operates efficiently, with removal efficiencies for Total Suspended Solids (TSS), Chemical Oxygen Demand (COD), and Biochemical Oxygen Demand (BOD) at 98.3 %, 95.1 %, and 96.1 %, respectively. The outlet Dissolved Oxygen (DO) of 1.9 mg/L meets local wastewater reuse standards. Furthermore, the GPS-X model forecasts the plant's performance under different scenarios, suggesting the feasibility of a new layout within 20-25 years and the need for additional units after 40 years. As inflow approaches maximum design capacity, simulation results underscore the importance of utilising the full plant design and expanding it for optimal operation over 60 years. This research provides critical insights for improving WWTP performance and emphasizes the significance of strategic planning in addressing long-term environmental management challenges. Moreover, this study represents a pioneering effort in addressing critical water scarcity challenges in Jordan by exploring the potential of treated wastewater (TWW) as a sustainable solution, thus contributing to the advancement of environmental management practices in the region.

Simulation study of a practical approach to enhance cadmium removal via biological treatment by controlling the concentration of MLSS

The fate of cadmium at the Muharram Aisha wastewater treatment plant in Karbala governorate, Iraq was studied using the TOXCHEM model. Cadmium, a known carcinogen, and is considered one of the most dangerous heavy metals and high concentrations, greater than permissible limits, were found in the treated wastewater. The plant operates using an activated sludge system and this was modeled via TOXCHEM with a sensitivity analysis carried out on the extended aeration system. Prior to analysis, the model was calibrated and validated for cadmium, with the adjustments leading to a mean square error (RMSE) and correlation coefficient (R) of 0.0001 and 0.81, respectively. The mass balance of cadmium in the Muharram Aisha treatment plant was found to be 4832.44 g/day (37.1726%) in the treated wastewater and 8164.52 g/day (62.804%) in the sludge, which indicated that the mix liquor suspended solid (MLSS) was the most sensitive factor. The sensitivity to cadmium was analyzed via MLSS in the extended aeration system and the results o indicated that the higher the MLSS concentration (mg/L), the greater the removal of cadmium in the treated wastewater. It was found that increasing the MLSS through a biological treatment method reduced the concentration of cadmium without the need for additional of any (potentially harmful) chemical treatments. The plant was subsequently operated for a period of 5 months with the MLSS increased from 1500 to 4500 mg/L, and this reduced the concentration of cadmium in the wastewater from 0.36 to 0.01 mg/L as a consequence. This research demonstrates how the novel application of TOXCHEM can be a useful tool in the reduction of heavy metal contamination in the environment.

Assessment and modeling of effluent quality, economic benefits, and greenhouse gas reduction for receiving brewery wastewater on A2O by GPS-X

Recently, breweries have been allowed to discharge brewery wastewater (BWW) to the sewage pipe network to alleviate the shortage of carbon sources of municipal wastewater treatment plants (MWTPs) under the premise of signing a contract with MWTPs in some countries. This study aims to provide a model-based method for MWTPs to evaluate the threshold, the effluent risk, the economic benefits, and the potential greenhouse gas (GHG) emissions reduction of receiving BWW. In this research, a simulation model of an anaerobic-anoxic-oxic process (A²O) receiving BWW was established based on the data of a real MWTP and brewery using GPS-X. The sensitivity factors of 189 parameters were analyzed, and several sensitive parameters were calibrated stably and dynamically. By analyzing the errors and standardized residuals, the calibrated model was proved to be high-quality and reliable. In the next phase, the impact of receiving BWW on the A²O was evaluated in terms of effluent quality, economic benefits, and GHG emissions reduction. The results showed that receiving a certain amount of BWW can effectively reduce the carbon source cost and GHG emissions for the MWTP compared with adding methanol. Though the chemical oxygen demand (COD), biochemical oxygen demand in five days (BOD₅), and total nitrogen (TN) in the effluent increased in various degrees, the effluent quality still met the discharge standard implemented by the MWTP. The study can also facilitate the modeling work for many researchers and promote more kinds of food production wastewater to be treated equally.

Developing a practical model for the optimal operation of wastewater treatment plant considering influent characteristics

Wastewater treatment plants (WWTPs) play an important role in protecting the quality of water sources. The optimum operation of WWTPs in response to continuous changes in the characteristics of the influent of the WWTP is very important, and it can improve the quality of the effluent of the WWTP. In this study, an approach for optimal operation of the WWTP has been presented considering the quantitative and qualitative variables of influent. In the proposed method, first, the simulation model of WWTP is developed and calibrated using the recorded data of its influent and effluent characteristics as well as operation conditions. Then, the influent is classified into clusters quantitatively and qualitatively k-means clustering method. In the final step, after determining the effective operation parameters, the AMOEA-MAP optimization algorithm is used to determine the optimal values of operation parameters for each cluster of influents based on its quantitative and qualitative characteristics including flow rate, COD, ammonium, and temperature. The proposed approach was implemented on a WWTP in the South of Tehran, the capital of Iran. Dissolved oxygen (DO) in the aeration tank, waste-activated sludge flow rate (Q_WAS) and the ratio of the supernatant flow rate of the sludge dewatering unit to the effluent flow rate (Q_d/Q_e) were considered as operation parameters affecting the performance of the system in removing pollutants and their optimal values were obtained as DO, 0.25-1.7 mg/l, Q_WAS, 875-2000 m³/day, and Q_d/Q_e, 10-14%. Using this method, i.e., changing system operation conditions based on influent characteristics, has improved the performance of a system in reducing COD, ammonium, and nitrate in the effluent by 11-41, 17-20 and 15-34, respectively.

Applying novel methods in conventional activated sludge plants to treat low-strength wastewater

Conventional activated sludge system is confidently widely used for biological treatment plants of municipal wastewater but suffering from operation problems that affect their efficiencies and effluent qualities, especially when treating low-strength wastewater with increasing incoming flow. The objective of this study is to evaluate and compare the novel methods used in upgrading conventional activated sludge treatment systems receiving low-strength wastewater to generate good effluent quality. GPS-X Simulator V 8.0 was used for model calibration and plant performance prediction. The calibrated GPS-X model proved that eliminating primary settling from the treatment process does not affect BOD5 and COD removal, while TSS removal is decreased, and NH4-N removal is increased. Increasing the return activated sludge flow from 50 to 150% of influent flow does not affect conventional activated sludge process, while the change of waste activated flow had a vital effect on process performance. The presence of an anoxic zone in conventional activated sludge processes treating low-strength wastewater has no significant impact on plant performance. Also, the model outputs proved that adding filling media to the aeration tank was able to handle an increase of influent flow and a stable performance of BOD5, and NH4-N removal was observed.

Modeling of novel processes for eliminating sidestreams impacts on full-scale sewage treatment plant using GPS-X7

The novel process consisted of two steps was established by combining all sidestreams lines (supernatant gravity thickener, underflow mechanical thickener, and centrate), treating them together away from the mainstream treatment plant, and returning treated sidestreams effluents to the plant outfall instead of plant head. The two steps novelty treatment combined degradation, nitrification, and dilution processes. To treat combined sidestreams, a novel pilot extended nutrient moving bed biofilm reactor was developed. The effects of sidestream elimination on a full-scale anaerobic/anoxic/oxic system were simulated using GPS-X7. The statistical results of R values greater than 0.8 and NMSE values near zero proved the calibrated model's validation. The novel system successfully removed 98, 93, 100, 85, 98, 100, and 98% of BOD, COD, NH₄, NO₃, TSS, H₂S, and PO₄-P from sidestreams, respectively. Furthermore, the simulation results showed that eliminating sidestreams has reduced volumes of full-scale A²/O facilities, controlled hydraulic and pollutants shocks, and minimized cost and energy. The novel process proved successful in treating combined sidestreams and eliminating their impacts on the A/O² system.

Process Optimization and Modeling of Phenol Adsorption onto Sludge-Based Activated Carbon Intercalated MgAlFe Ternary Layered Double Hydroxide Composite

A sewage sludge-based activated carbon (SBAC) intercalated MgAlFe ternary layered double hydroxide (SBAC-MgAlFe-LDH) composite was synthesized via the coprecipitation method. The adsorptive performance of the composite for phenol uptake from the aqueous phase was evaluated via the response surface methodology (RSM) modeling technique. The SBAC-MgAlFe-LDH phenol uptake capacity data were well-fitted to reduced RSM cubic model (R² = 0.995, R²-adjusted = 0.993, R²-predicted = 0.959 and p-values < 0.05). The optimum phenol adsorption onto the SBAC-MgAlFe-LDH was achieved at 35 °C, 125 mg/L phenol, and pH 6. Under the optimal phenol uptake conditions, pseudo-first-order and Avrami fractional-order models provided a better representation of the phenol uptake kinetic data, while the equilibrium data models’ fitting follows the order; Liu > Langmuir > Redlich–Peterson > Freundlich > Temkin. The phenol uptake mechanism was endothermic in nature and predominantly via a physisorption process (ΔG° = −5.33 to −5.77 kJ/mol) with the involvement of π–π interactions between the phenol molecules and the functionalities on the SBAC-LDH surface. The maximum uptake capacity (216.76 mg/g) of SBAC-MgAlFe-LDH was much higher than many other SBAC-based adsorbents. The improved uptake capacity of SBAC-LDH was attributed to the effective synergetic influence of SBAC-MgAlFe-LDH, which yielded abundant functionalized surface groups that favored higher aqueous phase uptake of phenol molecules. This study showcases the potential of SBAC-MgAlFe-LDH as an effective adsorbent material for remediation of phenolic wastewater

Model-based strategy for nitrogen removal enhancement in full-scale wastewater treatment plants by GPS-X integrated with response surface methodology

Model simulation is an effective approach to optimize the operational performance of wastewater treatment plants (WWTPs). This study presents a novel strategy to enhance the total nitrogen (TN) removal in WWTPs by GPS-X integrated with response surface methodology. The sensitivities of 61 parameters were screened and analyzed, and 6 critical parameters (i.e., μ_{max A}, K_A/a, μ_{max H}, K_H/ss, Y_H and μ_maxPAO) were selected for further adjustment. The accuracy of GPS-X for WWTPs modeling was validated by static and dynamic simulations with actual operational data. The results showed that the DO concentration diffused in different biological compartments exhibited significant effects on the denitrification rate. The TN removal is also associated with SRT. The significance and optimization orders of key parameters were analyzed. With the optimization of DO in biological units and SRT, the nitrification and denitrification rates were improved to 97.1 and 85.3% respectively, saving 17.9% energy consumption.