Monroe L. Weber-Shirk S chool of Civil and Environmental Engineering Nutrient Removal Project Project rationale Sequencing Batch Reactor Software that makes decisions Project rationale Sequencing Batch Reactor Software that makes decisions

Global Need for Better Nutrient Management ä Coastal dead zones ä Fish kills ä Migratory routes blocked ä Loss of diverse ocean ecosystems ä Human Population ä Agribusiness ä Coastal dead zones ä Fish kills ä Migratory routes blocked ä Loss of diverse ocean ecosystems ä Human Population ä Agribusiness

Long Island Sound: August 1998

Long Island Sound Study ä The LISS adopted a plan in 1998 to reduce nitrogen loads from human sources in the Sound by 58.5% ä The greatest human sources of nitrogen in the Sound are from wastewater treatment plants discharging into waters within the Long Island Sound watershed, or directly into the Sound itself ä A major component of the nitrogen reduction plan includes the need for wastewater treatment upgrades that emphasize nitrogen removal ä The LISS adopted a plan in 1998 to reduce nitrogen loads from human sources in the Sound by 58.5% ä The greatest human sources of nitrogen in the Sound are from wastewater treatment plants discharging into waters within the Long Island Sound watershed, or directly into the Sound itself ä A major component of the nitrogen reduction plan includes the need for wastewater treatment upgrades that emphasize nitrogen removal

Gulf of Mexico ä The "Dead Zone", or hypoxic zone, is a 7,000 square mile expanse of oxygen-depleted waters that cannot sustain most marine life ä Human activity has resulted in a significant increase in nitrogen flux ä Nitrogen sources include ä Industry ä Municipal waste water treatment ä Agriculture ä Fertilizer ä Livestock manure ä The "Dead Zone", or hypoxic zone, is a 7,000 square mile expanse of oxygen-depleted waters that cannot sustain most marine life ä Human activity has resulted in a significant increase in nitrogen flux ä Nitrogen sources include ä Industry ä Municipal waste water treatment ä Agriculture ä Fertilizer ä Livestock manure

Gulf of Mexico

Bottom water hypoxia: Frequency of midsummer occurrence

reduced nitrogen Reducing the Footprint of a Growing Global Population ä Conventional activated sludge process ä Removes BOD (organic carbon to CO 2 ) ä Nitrification ä Removes TKN (organic nitrogen and ammonia to nitrite and nitrate) ä TKN: Total Kjeldahl Nitrogen (______________) ä Denitrification ä Removes nitrite and nitrate by conversion to N 2 gas ä Conventional activated sludge process ä Removes BOD (organic carbon to CO 2 ) ä Nitrification ä Removes TKN (organic nitrogen and ammonia to nitrite and nitrate) ä TKN: Total Kjeldahl Nitrogen (______________) ä Denitrification ä Removes nitrite and nitrate by conversion to N 2 gas

NRP Goals ä Remove organic carbon and perhaps nitrogen from a waste containing BOD and TKN ä Concentrated synthetic waste will be stored in a refrigerator ä Dilute the waste with tap water to obtain specified waste concentration ä Reactor will be a sequencing batch reactor (SBR) rather than continuous flow ä Remove organic carbon and perhaps nitrogen from a waste containing BOD and TKN ä Concentrated synthetic waste will be stored in a refrigerator ä Dilute the waste with tap water to obtain specified waste concentration ä Reactor will be a sequencing batch reactor (SBR) rather than continuous flow

Sequencing Batch Reactor: Example Operation 4 h BOD 0 Biomass Add tap water Add concentrated waste AerateSettleDischarge Clean Supernatant

This Week’s Objectives ä Build a piece of a WWTP that includes: ä Aeration ä Cycled valve in air line using damper bottle ä Automated Empty/Fill-Dilute cycle ä Write code that makes decisions ä Build a piece of a WWTP that includes: ä Aeration ä Cycled valve in air line using damper bottle ä Automated Empty/Fill-Dilute cycle ä Write code that makes decisions

NRP Software Structure: Parallel Processes ä Data Acquisition ä Process Control ä Make decisions based on data ä Send command to Stamp Microprocessor to Control valves, pumps, stirrers ä Data logging to file ä Plot data on graph ä Handle Operator Commands ä Data Acquisition ä Process Control ä Make decisions based on data ä Send command to Stamp Microprocessor to Control valves, pumps, stirrers ä Data logging to file ä Plot data on graph ä Handle Operator Commands

Data Requirements for Making Decisions ä Data rate is approximately 50 Hz ä Many of the processes we are monitoring vary slowly with changes occurring over many minutes ä At least one of the processes (aeration) has rapidly varying pressures ä Some of the data is noisy ä What kind of data would you like in order to make the best decisions? ä When has tank reached target volume? ä When has air accumulator reached target pressure? ä Data rate is approximately 50 Hz ä Many of the processes we are monitoring vary slowly with changes occurring over many minutes ä At least one of the processes (aeration) has rapidly varying pressures ä Some of the data is noisy ä What kind of data would you like in order to make the best decisions? ä When has tank reached target volume? ä When has air accumulator reached target pressure?

Data Storage Code ä Write ä input of sensor data ä Output - none ä Read average (requires length of time) ä Output - array of averaged sensor data ä Read recent ä Output - array of most recent sensor data ä Read all ä Output - 2-d array all sensor data in buffer ä Configure ä Set size of buffer (number of sensor scans to store) ä Clear ä Empties buffer ä Write ä input of sensor data ä Output - none ä Read average (requires length of time) ä Output - array of averaged sensor data ä Read recent ä Output - array of most recent sensor data ä Read all ä Output - 2-d array all sensor data in buffer ä Configure ä Set size of buffer (number of sensor scans to store) ä Clear ä Empties buffer

Data Acquisition Loop Sets minimum data interval Gets sensor data from DataServer Stores sensor data in buffer Integrates air flow

Data Log Loop ä Where does the data come from?

Process Control Loop Control logic (chooses the state) Sends the control settings to the Stamp Microprocessor

Plant Control Current state chooses case Array of all sensors averaged Scaled value of reactor volume (measured) Target value (set point) Case structure New state

Identify the States and Decision Variables StateDecision variable ä _______________________ StateDecision variable ä _______________________ Drain Settle Fill with waste Fill with water Time or O 2 consumption Tank depth Tank depth or Time Tank depth Aerate Time

Data Structure for States ä States = ______ ä Use an enumerated type to keep track of state ä Associates a descriptive string with a number ä Useful for making self-documenting code ä Much better than (state 1, state 2, …) ä Control settings (valve positions, etc.) are determined by current state ä States = ______ ä Use an enumerated type to keep track of state ä Associates a descriptive string with a number ä Useful for making self-documenting code ä Much better than (state 1, state 2, …) ä Control settings (valve positions, etc.) are determined by current state Cases

Code with a Memory ä How could we know what the state was the last time? ä Shift registers and while loops that execute once (every time the code is called) ä Keep track of current state ä New state is an _________ ä How could we know what the state was the last time? ä Shift registers and while loops that execute once (every time the code is called) ä Keep track of current state ä New state is an _________ indicator

Assignment (due before lab on Wednesday) ä LabVIEW tutorial (see syllabus link) ä Create a VI with the following characteristics: ä it allows the user to convert a temperature reading in Kelvin, Celsius or Fahrenheit to Kelvin, Celsius or Fahrenheit. ä it runs continuously (without using the continuous run button!) ä it stops when you press a stop button on the front panel ä it uses at least one SubVI ä LabVIEW tutorial (see syllabus link) ä Create a VI with the following characteristics: ä it allows the user to convert a temperature reading in Kelvin, Celsius or Fahrenheit to Kelvin, Celsius or Fahrenheit. ä it runs continuously (without using the continuous run button!) ä it stops when you press a stop button on the front panel ä it uses at least one SubVI