Prioritize effluent quality, operational costs or global warming? – Using predictive control of wastewater aeration for flexible management of objectives in WRRFs
Autor: | Peter Steen Mikkelsen, Henrik Madsen, Peter Alexander Stentoft, Luca Vezzaro, Borja Valverde-Pérez, Thomas Munk-Nielsen, Jan Kloppenborg Møller |
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Rok vydání: | 2021 |
Předmět: |
Economic MPC
Marginal cost N2O emissions Environmental Engineering Total cost 0208 environmental biotechnology Nitrous Oxide 02 engineering and technology Wastewater 010501 environmental sciences Global Warming Waste Disposal Fluid 01 natural sciences SDG 7 - Affordable and Clean Energy Waste Management and Disposal Effluent 0105 earth and related environmental sciences Water Science and Technology Civil and Structural Engineering business.industry Ecological Modeling Environmental engineering Pollution 020801 environmental engineering Model predictive control Electricity generation Activated sludge Greenhouse gas Water Resources Environmental science Electricity business Management by objectives Nonlinear MPC |
Zdroj: | Stentoft, P A, Munk-Nielsen, T, Møller, J K, Madsen, H, Valverde-Pérez, B, Mikkelsen, P S & Vezzaro, L 2021, ' Prioritize effluent quality, operational costs or global warming? – Using predictive control of wastewater aeration for flexible management of objectives in WRRFs ', Water Research, vol. 196, 116960 . https://doi.org/10.1016/j.watres.2021.116960 |
ISSN: | 0043-1354 |
Popis: | This study presents a general model predictive control (MPC) algorithm for optimizing wastewater aeration in Water Resource Recovery Facilities (WRRF) under different management objectives. The flexibility of the MPC is demonstrated by controlling a WRRF under four management objectives, aiming at minimizing: (A) effluent concentrations, (B) electricity consumption, (C) total operations costs (sum electricity costs and discharge effluent tax) or (D) global warming potential (direct and indirect nitrous oxide emissions, and indirect from electricity production) . The MPC is tested with data from the alternating WRRF in Norre Snede (Denmark) and from the Danish electricity grid. Results showed how the four control objectives resulted in important differences in aeration patterns and in the concentration dynamics over a day. Controls B and C showed similarities when looking at total costs, while similarities in global warming potential for controls A and D suggest that improving effluent quality also reduced greenhouse gasses emissions. The MPC flexibility in handling different objectives is shown by using a combined objective function, optimizing both cost and greenhouse emissions. This shows the trade-off between the two objectives, enabling the calculation of marginal costs and thus allowing WRRF operators to carefully evaluate prioritization of management objectives. The long-term MPC performance is evaluated over 51 days covering seasonal and inter-weekly variations. On a daily basis, control A was 9–30% cheaper on average compared to controls A, D and to the current rule-based control. Similarly, control D resulted on average in 35–43% lower greenhouse gasses daily emission compared to the other controls. Difference between control performance increased for days with greater inter-diurnal variations in electricity price or greenhouse emissions from electricity production, i.e. when MPC has greater possibilities for exploiting input variations. The flexibility of the proposed MPC can easily accommodate for additional control objectives, allowing WRRF operators to quickly adapt the plant operation to new management objectives and to face new performance requirements. |
Databáze: | OpenAIRE |
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