Experimental Study and Mathematical Modeling of Enhanced Biological Phosphorus Removal Based on Aeration Effects

Experimental Study and Mathematical Modeling of Enhanced Biological Phosphorus Removal Based on Aeration Effects
Author: Parnian Izadi
Publisher:
Total Pages: 0
Release: 2021
Genre:
ISBN:

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Enhanced Biological Phosphorus Removal (EBPR), as a promising technology, has been implemented in many wastewater treatment plants (WWTP) worldwide, with high efficiency in phosphorus removal performance. In a well-operated EBPR, lower operational cost, reduced sludge production, and lower environmental impacts are achievable. Yet, with the proven capability of EBPR in efficient phosphorus removal, disturbance and periods of unexplained insufficient phosphorus removal have been detected in real WWTP in different cases due to loss of PAO biomass under presumed favorable conditions for EBPR. These complications may lead to process upset, system failure, and violation of discharge regulations. Disruption in process performance may originate from several external factors such as heavy rainfall, excessive nitrate loading to the anaerobic reactor, excessive aeration of activated sludge, or it may be a result of PAOs competition with other groups of microorganisms such as glycogen accumulating organisms (GAO). Therefore, the key in reaching low P-effluent levels is to optimize the operation and minimize the effect of inefficient factors. This Ph.D. study has focused on aeration as a crucial operational factor in the EBPR process in sequential batch reactor (SBR) systems. EBPR aerobic P-uptake, anaerobic P-release, and carbon storage of phosphorus accumulating organisms (PAOs) are closely related to oxygen mass transfer. The study is oriented to different aspects of aeration, addressing aeration concentration (dissolved oxygen (DO) concentration), aeration duration (aerobic hydraulic retention time (HRT)), and aeration pattern (continuous/intermittent). The performance of EBPR in SBRs under various aeration strategies was investigated for different DO concentrations (0.4-4 mg/L), HRT (120-320 minute), and aeration patterns of continuous and intermittent (25 to 50 minute on/off intermittent aeration/non-aeration intervals). Moreover, this study investigated the effect of reaching micro-aeration with adaptation strategies on EBPR performance. The development of steady and instant-DO reduction in different aeration strategies was studied in batch tests with enriched PAOs at different DO levels. Subsequently, comparative modeling using calibrated BioWin software was implemented for SBRs to predict the nutrient removal performance by changing DO concentration and the aerobic-HRT and understanding the effect of parameters on treatment performance to improve operation and control.

Effect of Sulphide on Enhanced Biological Phosphorus Removal

Effect of Sulphide on Enhanced Biological Phosphorus Removal
Author: Francisco Javier Rubio Rincon
Publisher: CRC Press
Total Pages: 293
Release: 2017-03-03
Genre: Technology & Engineering
ISBN: 135164808X

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The enhanced biological removal of phosphorus (EBPR) is a popular process due to high removal efficiency, low operational costs, and the possibility of phosphorus recovery. Nevertheless, the stability of the EBPR depends on different factors such as: temperature, pH, and the presence of toxic compounds. While extensive studies have researched the effects of temperature and pH on EBPR systems, little is known about the effects of different toxic compounds on EBPR. For example, sulphide has shown to inhibit different microbial activities in the WWTP, but the knowledge about its effects on EBPR is limited. Whereas the sulphide generated in the sewage can cause a shock effect on EBPR, the continuously exposure to sulphide potentially generated in WWTP can cause the acclimatization and adaptation of the biomass. This research suggests that sulphate reducing bacteria can proliferate in WWTP, as they are reversibly inhibited by the recirculation of sludge through anaerobic-anoxic-oxic conditions. The research enhances the understanding of the effect of sulphide on the anaerobic-oxic metabolism of PAO. It suggests that the filamentous bacteria Thiothrix caldifontis could play an important role in the biological removal of phosphorus. It questions the ability of PAO to generate energy from nitrate respiration and its use for the anoxic phosphorus uptake. Thus, the results obtained in this research can be used to understand the stability of the EBPR process under anaerobic-anoxic-oxic conditions, especially when exposed to the presence of sulphide.

Modeling Biological Phosphorus Removal in Activated Sludge Systems

Modeling Biological Phosphorus Removal in Activated Sludge Systems
Author: D. Brdanovic
Publisher: CRC Press
Total Pages: 272
Release: 2021-10-01
Genre: Science
ISBN: 1000657981

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This text looks at different effects on the process of biological phosphorus removal. Topics include: biological phosphorus removal processes; process and molecular ecological studies; and the effect of potassium limitation on biological phosphorus removal.

Evaluation of Phosphorus Removal/recovery Processes During Municipal Wastewater Treatment

Evaluation of Phosphorus Removal/recovery Processes During Municipal Wastewater Treatment
Author: Rania Bashar
Publisher:
Total Pages: 107
Release: 2018
Genre:
ISBN:

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With growing emphasis on environmental and economic sustainability worldwide, modern municipal wastewater treatment plants (WWTPs) are striving to reduce consumption of resources and ensure increased recycling and reuse of nutrients and energy contained in the wastewater. In a trade-off between enhanced P removal (to meet stringent effluent limits) and increased resource (e.g., energy, chemical) usage, it is critical for the treatment plants to be able to select the most appropriate technology. To this end, this study has combined mathematical modeling and experimental data from recent literature to perform a comprehensive evaluation of established/emerging P recovery/removal technologies considering technical, economic and energy sustainability aspects. For technical evaluations, full-scale designs of high performing P removal technologies (e.g., Modified University of Cape Towne process, Bardenpho process, membrane bioreactors, IFAS-EBPR, struvite recovery, tertiary reactive media filtration) were developed and simulated using a widely-used Windows-based process model simulating software BioWin v. 5.3 (EnviroSim Associates Ltd., Canada). The treatment configurations were evaluated in terms of performance and cost effectiveness ($/lb of P removed). Results show that the unit cost for P removal in different treatment alternatives range from $42.22 to $60.88 per lb of P removed. The MUCT BNR+ tertiary reactive media filtration proved to be one of the most cost effective configurations ($44.04/lb P removed) delivering an effluent with total P (TP) concentration of only 0.05 mg/L. Although struvite recovery resulted in significant reduction in biosolids P, the decrease in effluent TP was not sufficient to meet very stringent discharge standards. Emerging low energy mainline (LEM) treatment layouts consisting of energy efficient and innovative technologies has the potential to improve the overall sustainability of WWTPs. To evaluate the LEM treatment schemes, a configuration consisting of fine screen pretreatment, anaerobic membrane bioreactor (AnMBR) for BOD and TSS removal, reactive filter media for adsorptive P removal, and cold partial nitritation/Anammox process for N removal was simulated using operational conditions that are typical for a mid-size WWTP in the US. Our simulation results indicated that the LEM scheme could reduce the net energy requirement for treatment by about 0.46 kWh/m3 (~ 94%) compared to a conventional activated sludge system. The removal efficiencies of TN, TP and TCOD in the effluent were 93%, 90% and 94%, respectively. One-at-a-time (OAT) sensitivity analysis indicated that dominant parameters controlling energy production and consumption include temperature, wastewater influent COD, and electric efficiency of combined heat and power (CHP) engine. The LEM treatment scheme reached a break-even point (energy-self-sufficiency) at 544 mg/L COD and 38% electric efficiency of the CHP engine. The OAT analysis was further expanded using global sensitivity analysis (GSA) techniques to identify the within parameter interactions. The GSA revealed CHP efficiency has a predominantly linear (non-interacting with other inputs) impact on the net energy requirement and has the potential to be a very good control parameter in achieving energy self-sufficiency. In addition, a solution space for energy-positive operation was also identified in this study where minimum non-linear interaction between input parameters is present. Therefore, operating the treatment plant within this linear region ensures maximum control over net energy requirement, while staying within the energy positive range. The results of this study will provide guidance for researchers, municipalities, government agencies and decision-makers, and other stake-holders in choosing the most appropriate P removal option that offer the possibility to move wastewater treatment towards a sustainable, energy- and resource-positive direction.

Mathematical Modelling and Computer Simulation of Activated Sludge Systems

Mathematical Modelling and Computer Simulation of Activated Sludge Systems
Author: Jacek Makinia
Publisher: IWA Publishing
Total Pages: 682
Release: 2020-03-02
Genre: Science
ISBN: 1780409516

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Mathematical Modelling and Computer Simulation of Activated Sludge Systems – Second Edition provides, from the process engineering perspective, a comprehensive and up-to-date overview regarding various aspects of the mechanistic (“white box”) modelling and simulation of advanced activated sludge systems performing biological nutrient removal. In the new edition of the book, a special focus is given to nitrogen removal and the latest developments in modelling the innovative nitrogen removal processes. Furthermore, a new section on micropollutant removal has been added. The focus of modelling has been shifting in the last years to models that can describe the performance of a whole plant (plant-wide modelling). The expanded part of this new edition introduces models describing the most important processes interrelated with the mainstream activated sludge systems as well as models describing the energy balance, operating costs and environmental impact. The complex process evaluation, including minimization of energy consumption and carbon footprint, is in line with the present and future wastewater treatment goals. By combining a general introduction and a textbook, this book serves both intermediate and more experienced model users, both researchers and practitioners, as a comprehensive guide to modelling and simulation studies. The book can be used as a supplemental material at graduate and post-graduate levels of wastewater engineering/modelling courses.