Integrated control of combined sewer system and wastewater treatment plants during rainfall events

Transcription

1 Integrated control of combined sewer system and wastewater treatment plants during rainfall events Nikolaj Mølbye, Krüger A/S Morten Grum, Luca Vezzaro, Krüger A/S Arne Møller, DHI Lene Bassø, Aarhus Water Prepared enabling change 1

2 Outline RTC layers in Aarhus Dynamic Overflow Risk Assessment (DORA) the global control strategy how does it work The heartbeatcycle Implementation and monitoring Prepared enabling change 2

3 RTC Layers in Aarhus DIMS.CORE Short term rainfall forecasts (MAR) Predicted Run-off (MIKE Urban) Dynamic Overflow Risk Assessment (DORA) WWTP max. hydraulic load Layer 3 Data validation and - filtration Software sensors: (elevations, flows, max. flows, storage tank filling) PID (Flows) at each storage tank PID (Elevations) at each storage tank PID output: 0-100% distributed to setpoints for pumps, weirs/gates at each storage tank Layer 2 Levels, flows and weir/gate positions Set-points PLC/SCADA Sensors/Actuators Layer 1 Layer 0

4 Agenda RTC control layers in Aarhus Dynamic Overflow Risk Assessment (DORA) the global control strategy how does it work The heartbeatcycle Implementation and monitoring Prepared enabling change 4

5 The DORA global control strategy Q Q Q Q Expected CSO Cost Q Q Q Minimize total expected CSO Cost in catchment by controlling Q

6 DORA elements (1) i-th basin V B,i Uncertain Q OV,i Q F,i Q IN,i Defined by upstream basin(s) V w,i Q OUT,i Controlled by DORA Inflow-outflow V w,now T cr (Q IN - Q OUT ) V CR Critical volume, available volume for storage Must be maximized Now Critical Time, T cr Time

7 DORA elements (2) Q F Runoff volume V F Time Uncertainty on volume prediction Now Critical Time, T cr Overflow probability V F V CR T cr (Q IN - Q OUT ) V F pdf V w

8 Expected CSO cost due to forecasted runoff p probability p( V F,i ) Probability of overflow volume is calculated V cr,i V F,i C F, i = C( VF, i ) p( VF, i ) V CR, i dv F, i C Cost is calculated by using a linear overflow-cost function Cost ) ( ) C V F,i C( VF i ) = ci VOV, i = ci ( VF, i Vcr,, i ) V cr,i 0 V F,i V OV,i Specific costfactor

9 C( V ) = c V, = c ( V, V, F, i i OV i i F i cr i ) Specific costfactor Bathing area Not sensitive

10 C( V ) = c V, = c ( V, V, F, i i OV i i F i cr i ) Specific costfactor Bathing area Not sensitive A genetic algorithm finds flows that minimize total expected cost

11 DORA The flexible cost function Cost = N ba ( sin s C + ) cr, i CF, i Chor, i i= 1 Cost due to water already fallen in the catchment Cost due to forecasted runoff Costdiscount accounting for unknown future Q F? Time Forecast horizon, T hor

12 Agenda RTC control layers in Aarhus Dynamic Overflow Risk Assessment (DORA) the global control strategy how does it work The heartbeatcycle Implementation and monitoring Prepared enabling change 12

13 DIMS.CORE Heartbeatcycle Short term rainfall forecasts (MAR) Predicted Run-off (MIKE Urban) DORA calculationloop every 5 min Dynamic Overflow Risk Assessment (DORA) WWTP max. hydraulic load Data validation and - filtration Software sensors: flows, max. flows, storage tank filling PID (Flows) at each storage tank PID output: 0-100% distributed to setpoints for pumps, weirs/gates at each storage tank Levels Set-points PLC/SCADA Sensors/Actuators

14 Heartbeatcycle DIMS.CORE Local control calculationloop every 1 min Data validation and - filtration Software sensors: flow PID (Flows) at each storage tank PID output: 0-100% distributed to setpoints for pumps, weirs/gates at each storage tank Levels Set-points PLC/SCADA Sensors/Actuators

15 Agenda RTC control layers in Aarhus Dynamic Overflow Risk Assessment (DORA) the global control strategy how does it work The heartbeatcycle Implementation and monitoring Prepared enabling change 15

16 Implementation and monitoring Q Prepared enabling change 16

17 Implementation and monitoring Prepared enabling change 17

18 Expectations Preliminary calculations 25 rain events Prepared enabling change 18

19 Thank you Prepared enabling change 19