2015 ISA Water / Wastewater and Automatic Controls Symposium August 4-6, 2015 Orlando, Florida, USA

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1 Standards Certification Education & Training Publishing Conferences & Exhibits Utilizing Instrumentation and Control Tuning for BNR Optimization Speakers: Craig Fuller, AECOM Technical Services Norman Anderson, Polk County Charles Nichols, Polk County David Fitzgerald, D.P. Fitzgerald Donald Schlicht, Curry Controls Company 2015 ISA Water / Wastewater and Automatic Controls Symposium August 4-6, 2015 Orlando, Florida, USA

2 Presenter Craig Fuller, PE has over 10 years of experience in water and wastewater process design BS and MS level work in Ch.E. from the Florida Institute of Technology Member WEF/Florida Water Environment Association s Wastewater Process Committee Previous Member AIChE Environmental Division Aug 4-6, 2015 Orlando, Florida, USA 2

3 Presentation Outline Background of Expansion Simplified P&ID for Biological Controls Instrumentation Utilized Operating Conditions/Results Prior to Optimization Operating Conditions After Optimization HMI Examples Treatment Results Aug 4-6, 2015 Orlando, Florida, USA 3

4 Background Regional Plant Expanded/Started Up In 2012 Existing Biological Process Was Mechanical Aeration with PID Control Based on Dissolved Oxygen and Flow Numerous Biological Process Improvements MLE to BNR Process Incorporation of ORP Analyzers for control Installation of additional DO Analyzers Automated High Performance Butterfly Valves Pressure instrumentation for Air System Thermal Mass Flow Meters for Air System Automated VFD Driven PD Blowers for Air System Significant HMI Upgrades for Operator monitoring and control Aug 4-6, 2015 Orlando, Florida, USA 4

5 Simplified P&ID For Biological Controls Aug 4-6, 2015 Orlando, Florida, USA 5

BNR Instrumentation Utilized Analyzer Indicating Transmitters (4 ) with Local Displays Connects 6 Analytical Elements, Each Communication using Profibus DP provides additional analytical information

6 BNR Instrumentation Utilized Analyzer Indicating Transmitters (4 ) with Local Displays Connects 6 Analytical Elements, Each Communication using Profibus DP provides additional analytical information Transmitter and digital communication allows for multiple data points via a single transmitter and single cable but requires additional knowledge to maintain and a single failure can cause loss of multiple signals Careful planning, component selection, and system architecture design are critical for a successful Profibus implementation Displays are damaged by sunlight but can be removed Profibus susceptible to electrical surges/lightning Aug 4-6, 2015 Orlando, Florida, USA 6

BNR Instrumentation Utilized Analytical Elements = ORP (8), Luminescent DO (3), ph (5) ORP is used for primary oxygen demand measurement and process control Location is Critical ORP measures electron

DO and ph are provided for process monitoring Luminescent DO probes use a pulsed blue light and measures the emitted red light intensity and time off of the luminescent probe surface to quantify the

7 BNR Instrumentation Utilized Analytical Elements = ORP (8), Luminescent DO (3), ph (5) ORP is used for primary oxygen demand measurement and process control Location is Critical ORP measures electron movement during oxidation and reduction, and is useful in determining the type of biological activity occurring in the process Greater resolution than DO as it provides information even when DO = 0 DO and ph are provided for process monitoring Luminescent DO probes use a pulsed blue light and measures the emitted red light intensity and time off of the luminescent probe surface to quantify the amount of Dissolved Oxygen ph is measured similarly to ORP but is a measurement of potential related to the concentration of Hydrogen ions in solution ph is typical used as a relative measurement In BNR, when ph drops, it can mean nitrification has occurred In disinfection, a ph drop + high chlorine demand ~ high ammonia bleed through Aug 4-6, 2015 Orlando, Florida, USA 7

8 BNR Instrumentation Utilized Pressure Indicating Transmitters Communication using Profibus PA with PA to DP conversion used for common signal bus Controls blower header pressure to decouple from flow measurement used to split flow Aug 4-6, 2015 Orlando, Florida, USA 8

BNR Instrumentation Utilized Air Flow Element/Transmitter = Thermal Mass Flow Communication using Profibus DP Used for valve position control feedback to split flow off of the main blower air header

9 BNR Instrumentation Utilized Air Flow Element/Transmitter = Thermal Mass Flow Communication using Profibus DP Used for valve position control feedback to split flow off of the main blower air header Measures the heat convected from a heated surface to calculate fluid flow Thermal mass flow preferred for low moisture gas measurement due to accuracy, turndown, ease of installation and cost Aug 4-6, 2015 Orlando, Florida, USA 9

BNR Instrumentation Utilized Ultrasonic Level Element / Transmitter Communication using Profibus PA with PA to DP conversion used for common signal bus Used with PIT to control PD blowers state /

10 BNR Instrumentation Utilized Ultrasonic Level Element / Transmitter Communication using Profibus PA with PA to DP conversion used for common signal bus Used with PIT to control PD blowers state / speed Integration time 3 seconds averaging for PID Equalization Utilizes Plug Flow Valve and Electromagnetic Flow Meter Communication over Profibus DP Integration time 5 minute averaging for PID BNR equalization utilizes a plug flow control valve using a cascaded flow control loop The BNR level is elevated to limit the flow, based on a flow set point Allows constant treatment during equalization Aug 4-6, 2015 Orlando, Florida, USA 10

11 Basic BNR Control Basic aeration control parameters ORP is primary PID controller in a cascaded control loop Option to include bias for events such as holidays/flushing Air PID control loop still present in the event ORP has issues Probes selected, aerobic areas adjusts valves to DO setpoint ORP signal averaging from 0 60 seconds (selectable) Integration time 10 min averaging for PID AE used for control is selectable to provide feedback to PID loop for control or air/valves Aug 4-6, 2015 Orlando, Florida, USA 11

12 ORP for BNR Optimization Philosophy ORP is an indicator of Biological Activity Additionally, ORP can be measured when DO cannot. Optimally, an efficient aeration process would have almost zero DO, just enough to keep the bugs happy for biochemical activity. By measuring DO and ORP we can shoot for a zero DO and still know our process is active. By doing this, we can optimize our process AND save money at the same time by reducing our air requirements Aug 4-6, 2015 Orlando, Florida, USA 12

13 Operating Conditions Prior to Optimization Aug 4-6, 2015 Orlando, Florida, USA 13

14 Operating Conditions Prior to Optimization Basin 1 and 3 had 50/50 split of air flow to Zones 2 and 3 Measured by FI, adjusted through CV/FV Basin 2 and 4 had 50/50 split of air flow to Zones 3 and 4 Aug 4-6, 2015 Orlando, Florida, USA 14

15 Treatment Results Prior to Optimization Nutrients Would Build Up And the Process Could Not Stabilize Nitrate Levels Before Optimization (mg/l) Nitrate Gain Before Optimization (mg/l) Nitrate Level 0-1 Late Stage Nitrification Gain Aug 4-6, 2015 Orlando, Florida, USA 15

16 Calculations for Optimization Calculated Zones and Loading to Optimize Treatment Potential HRT SRT F/M Ratio MLSS Anoxic Zone Sizing Recycle Rates Changed location of ORP, Aeration Zones, air split between Aeration Zones Worked with Operations Staff to optimize ORP set points Increased Nitrate Recycle Rate Aug 4-6, 2015 Orlando, Florida, USA 16

17 Optimization: Parallel Aug 4-6, 2015 Orlando, Florida, USA 17

18 Optimization: Parallel Basins 1, 2, and 3 operate in parallel Increased N-Rcy due to additional pump in Basin 2 N-rcy pump speed increased from 50 Hz to 60 Hz Moved Aeration Zones from Zones 2 and 3 to Zones 3 and 4 Move ORP probe from Zone 3 to Zone 4 Increases size of Primary Anoxic Zone Substantially Decreases Nitrogen in effluent Stabilized De-nitrification Process Aug 4-6, 2015 Orlando, Florida, USA 18

19 Treatment During Optimization Anoxic Zones and Aeration Optimized Stable Mixed Liquor for Clarification Able to Treat Varied Influent Nutrient Load Differences Nitrate Decrease After Process Changes Decrease in Nitrates Aug 4-6, 2015 Orlando, Florida, USA 19

20 Parallel Operation in Extended Period Removed one tank from service to put one Oxidation Ditch into service During peak events, HRT and SRT would be too short for ideal treatment Lead to poor settling in clarifiers at times Result: Effluent nutrient increased but process still stable Increased ORP set points and split air 50/50 in Zones 3/4 Air demand could approach limit of Zone 4 aeration due to only two parallel tanks in operation Aug 4-6, 2015 Orlando, Florida, USA 20

21 Operator Control In order to control this process Operator s need clear and concise screens having the following functionality: Overview of the entire plant process to make sure everything is running smoothly at a glance Detailed information of complex processes Simple Operator controls that are intuitive and the necessary information and nothing more Challenges: How do you snapshot a large plant having SO much information? Remember we have digital ProfiBus communications having an immense amount of data at our fingertips. How do you show a complex process and still keep it simple? How do you provide operators with only the information they need? Aug 4-6, 2015 Orlando, Florida, USA 21

22 Operator s Plant Overview HMI Screen *Use the necessary information and do not be tempted just because it s available. (Made by an Operator for an Operator) Aug 4-6, 2015 Orlando, Florida, USA 22

23 HMI of Current BNR Operation Loaded with information Aug 4-6, 2015 Orlando, Florida, USA But what do these buttons do? 23

24 HMI of Current BNR Air Operation Decluttered Information shown is selectable to provide the needed information Aug 4-6, 2015 Orlando, Florida, USA 24

25 Treatment In Extended Period Eliminated one BNR basin from use Nitrates still below previous level (27% Decrease) Aug 4-6, 2015 Orlando, Florida, USA 25

26 Treatment In Extended Period Eliminated one BNR basin from use Phosphorous still below previous level (11% Decrease) Aug 4-6, 2015 Orlando, Florida, USA 26

27 Energy Savings Over Extended Period Decrease of 8.4% From Pre-Expansion Energy Use Despite ~4X Connected Load Decreased Standard Deviation by Nearly 79% Aug 4-6, 2015 Orlando, Florida, USA 27

28 Chlorine Savings Over Extended Period Decrease of 51% From Pre-Expansion Chlorine Use Decreased Standard Deviation by 86% Aug 4-6, 2015 Orlando, Florida, USA 28

29 Summary of Results Lower, More Stable Energy Costs (8.4% Decrease, 79% Decrease in Deviation) Savings of $44,000/year Lower, More Stable Chlorine Demand (51% Decrease, 86% Decrease in Deviation) Savings of $80,000/year Nitrate Decrease (27%, 83% When Optimized) No defined limit on effluent for PAR, RIB limit 12 mg/l Phosphorous Decrease (11%, 70% When Optimized) No defined limit on effluent for PAR system or RIB Stable Treatment for Varied Influent Loadings Virtually Eliminated Call-Outs and Off-Spec Issues Occurred weekly before expansion Aug 4-6, 2015 Orlando, Florida, USA 29

30 Questions/Bio of Authors Norman Anderson, PE has over 10 years experience in the design and commissioning of Process Control Systems for the Water Sector. Norman has an M.S. in EE from Iowa State University and an M.S. in Physics from the University of Florida. Charles Nichols has over 35 years of experience in the management and operation of primary, secondary, advanced, and reclaimed wastewater treatment facilities. Charles has an A Wastewater Treatment License in the State of Florida. David Fitzgerald, PE has over 25 years of experience in water and wastewater facility and process design. David has an M.S. in ME from the University of Florida and a B.S. in ME from Virginia Tech. Donald Schlicht, PE has over 30 years of experience in designing, building and programming control and instrumentation systems. This includes over 15 years in the water and wastewater area. Donald has a BSEE from Rice University. Aug 4-6, 2015 Orlando, Florida, USA 30

In wastewater treatment facilities, some

FWRJ Starting Up an Underloaded Biological Nutrient Removal Process Craig Fuller, Charles Nichols, Mark Addison, David Wilcox, and Dwayne Kreidler In wastewater treatment facilities, some unit processes