Water Treatment Plant Reflections S 1 Raw Water alum QT S 2 S 4 m 1 S 3 Flocculation Sedimentation p 1 S 5 Clearwell Clean Water S 1 S 1 Raw Water alum QQ TT S 2 S 2 S 4 S 4 m 1 m 1 S 3 S 3 Flocculation Sedimentation p 1 p 1

LabVIEW Software ä Writing software to control a water treatment plant is too complicated for a first programming assignment! ä I will provide fully functional software that allows some flexibility in configuring the plant ä You will need to add the code that controls the flow rate of the alum pump ä Writing software to control a water treatment plant is too complicated for a first programming assignment! ä I will provide fully functional software that allows some flexibility in configuring the plant ä You will need to add the code that controls the flow rate of the alum pump

When it doesn’t work! ä You are creating a complex system ä Any component that fails can lead to failure in the system ä What could you do if you assemble the entire system and it doesn’t “work” ä You are creating a complex system ä Any component that fails can lead to failure in the system ä What could you do if you assemble the entire system and it doesn’t “work”

Modular approach ä Break a system down into its components and test individual pieces ä What are the system components that can fail? ä Brainstorm! ä Break a system down into its components and test individual pieces ä What are the system components that can fail? ä Brainstorm!

Scientific Method of Troubleshooting ä The Scientific method: ä Create hypotheses ä Design experiments to test the hypotheses ä Draw conclusions based on the data ä How can you choose which components to test first? ä Intuition? ä Ask which component could cause the observed symptoms ä Requires a basic understanding of how the system works! ä The Scientific method: ä Create hypotheses ä Design experiments to test the hypotheses ä Draw conclusions based on the data ä How can you choose which components to test first? ä Intuition? ä Ask which component could cause the observed symptoms ä Requires a basic understanding of how the system works!

Automated System Hardware ä Controls ä Power supply ä Microproccessor ä can loose its program (download program again) ä May need to be reset by temporarily unplugging the power ä Water damage ä Valves ä Sensors ä Power supply ä Pressure sensors (wet, hole in diaphragm, installed backwards) ä Data acquisition hardware ä Noisy sensors (turbidity sensors are noisy) ä Controls ä Power supply ä Microproccessor ä can loose its program (download program again) ä May need to be reset by temporarily unplugging the power ä Water damage ä Valves ä Sensors ä Power supply ä Pressure sensors (wet, hole in diaphragm, installed backwards) ä Data acquisition hardware ä Noisy sensors (turbidity sensors are noisy)

Automated System Software ä Configuration ä voltages measured at a port are converted to physical units ä Sensor output is connected to a particular location in the plant for control logic ä Software may not do what the author thought it was going to do ä Malicious intent to frustrate students… ä Unintended programming errors ä Configuration ä voltages measured at a port are converted to physical units ä Sensor output is connected to a particular location in the plant for control logic ä Software may not do what the author thought it was going to do ä Malicious intent to frustrate students… ä Unintended programming errors

Hydraulic Challenges (getting the water to go where you want it to go) ä Leaks ä Connections not sufficiently tight ä Overflows ä Caused by water not going where you thought it was going ä Excessive head loss ä tubing size too small ä Valve orifice too small ä Leaks ä Connections not sufficiently tight ä Overflows ä Caused by water not going where you thought it was going ä Excessive head loss ä tubing size too small ä Valve orifice too small

Hydraulic Challenges ä Challenges from working at this small scale! ä Flow rate into the plant is controlled by the computer ä Water surface inside accumulator doesn’t need to be higher than the tank it is delivering water to! ä Control the water level in the sedimentation tank ä How? ä What does the outflow look like? ä Large scale (order 1 m) ä Tiny scale (order 1 mm) ä Our scale (order 5 mm) ä Challenges from working at this small scale! ä Flow rate into the plant is controlled by the computer ä Water surface inside accumulator doesn’t need to be higher than the tank it is delivering water to! ä Control the water level in the sedimentation tank ä How? ä What does the outflow look like? ä Large scale (order 1 m) ä Tiny scale (order 1 mm) ä Our scale (order 5 mm)

 p  R 2 = 2  R  Surface Tension ä Pressure increase in a spherical droplet pR2pR2 2R2R Surface molecules Temperature (C) Surface tension (N/m)

Example: Surface Tension ä Estimate the difference in pressure (in Pa) between the inside and outside of a droplet of water that is forming at the end of a tube of water. The tube is 3 mm in diameter. R = 1.5 x m  = N/m Water won’t flow from tube until the elevation difference exceeds 1 cm!

Hydraulic Challenges ä Flow control to the filter ä What is the potential energy difference that causes water to go through the filter? ä What happens as the filter head loss changes? ä If a water surface is moving, air must be moving too! ä Flow control to the filter ä What is the potential energy difference that causes water to go through the filter? ä What happens as the filter head loss changes? ä If a water surface is moving, air must be moving too!

Is there anything left to do? ä Plant hydraulics ä Design for robustness ä Think about anything that could happen that would cause a leak ä Alum flow control ä Graph plant parameters ä HMI (human machine interface) ä As a plant operator what would you like to know? ä How can you present this information in a easy to understand format? ä Plant hydraulics ä Design for robustness ä Think about anything that could happen that would cause a leak ä Alum flow control ä Graph plant parameters ä HMI (human machine interface) ä As a plant operator what would you like to know? ä How can you present this information in a easy to understand format?

Three Ways to Control Alum Pump ä Specify pump rpm ä Specify alum dose ä ___________________ ä Automatic ä ___________________ ä Specify pump rpm ä Specify alum dose ä ___________________ ä Automatic ä ___________________ Alum stock concentration Plant flow rate Tubing size Raw water turbidity Plant flow rate Tubing size

Manual rpm

Manual alum dose

Automatic Alum Dose

Automated Alum Dose

Pointers ä Stamp module must be on the computer side of the bench divider ä No one may operate their plant until both of the stamp modules on their bench are in safe locations ä Pressure sensors can fail if one drop of water soaks into the terminals ä Use manual valves to make it easy to drain tanks ä Include a manual shutoff valve at the plant influent ä Make sure your plant won’t cause a spill after you leave! ä Stamp module must be on the computer side of the bench divider ä No one may operate their plant until both of the stamp modules on their bench are in safe locations ä Pressure sensors can fail if one drop of water soaks into the terminals ä Use manual valves to make it easy to drain tanks ä Include a manual shutoff valve at the plant influent ä Make sure your plant won’t cause a spill after you leave!