CE 3372 Water Systems Design Lecture 08 –Lift Stations, Valves, EPA-NET Workshop

Overview Lift Stations Valves Project EPA-NET Workshop

Lift Stations Pump Review Lift Station Concepts

Lift Stations Lift wastewater/stormwater to higher elevations when: discharge of local collection system lies below regional conveyance terrain or man-made obstacles do not permit gravity flow to discharge point.

Pond and Pump Station

Types of Lift Stations Submersible Wet-well / dry-well Lower initial cost Lower capacity Smaller footprint Wet-well / dry-well Higher initial cost Easier inspection/ maintenance

Submersible lift station

Wet-well / dry-well lift station

Design criteria Size the pumps and the wet-well (sump) storage capacity to accommodate inflow variability and detention time limits. Match the pumps to the flow and head requirements. Provide ‘near-absolute’ reliability Automated controls Redundant systems Alarms Regularly scheduled, preventive maintenance Assess and mitigate environmental factors Flood risk, noise pollution, visibility

Site plan and facilities Protected and accessible during a major flood Redundant power supplies Intruder-resistant with controlled access

Head Head is energy per unit weight of water Energy = Kinetic + Potential Energy = Velocity + (Elevation + Pressure) EGL = Total head at point in the system Whoever thinks they can answer it, will get 10 pts. Not arbitrary term, or an elevation term even though units are feet. It’s energy required to move water. Water that’s static has pressure and elevation. Water bottle drop with knife, elevation vs ceiling (ex: res with 5ft elevation and 10 ft elevation)

Piezometer measure the pressure in the system at specific point Pitot measures the pressure and velocity in the system at specific Note: EGL and HGL are at the same at the reservoirs because of velocity. EGL. When water is rushing out the velocity of the water in the system increases quickly

How to select a Pump A quick overview Step 1 – Place system curves on chart (new and old) Step 2 – Select flow range (design requirements) High end = Peak flow + fire Low = Avg. daily Step 3 – Narrow down pumps based on operating point Step 4 – Check Efficiency! (75% +) and Select Pump Step 5 – If below 75%, try again with new Pump Curves

System Curve when OLD System Curve at NEW standards Old it takes MORE head to produce same amount of flow Step 1 – Place System Curves (new and old on there) Step 2 – Select Flow range you need to operate on (Design req.) 500-700 High end = Peak flow + fire Low = Avg daily Range can factor as much as twice Step 3 – Narrow down pumps based on operating point 7.25 is NOT going to work Step 4 – Look at efficiency!!! (75% +) System Curve at NEW standards

Pump and System Curves Pump Curve – How much energy the pump delivers to the water System Curve – How much energy it takes to deliver a flow rate to everyone in your distribution System, more flow rate, more resistance, needs more head (energy) Pump, more flow rate, can’t push up as far, head goes down. Because Pumps are producing head. System is not.

Valves

Valves Devices which control amount and direction of fluid flow in closed conduit systems Bronze, brass, iron, or steel alloy

Types of Valves Stop Valves – Used to completely/partially shut off flow of fluid (ex: globe, butterfly, gate, plug, needle) Check Valves – Used to permit flow in only one direction (ex: ball-check, swing-check, lift-check) Special Valves relief, pressure-reducing, remote-operated Globe is most used.

Globe Valve Disc attached to valve stem rests against seat to shut off flow of fluid

Gate Valve

Butterfly Valve Used in water. Fuel and ventilation systems

Valves in EPANET Valves are links Input Parameters Output Parameters Limit pressure of flow at a specific point in the network Input Parameters Start and end nodes Diameter Setting Status Output Parameters Flow rate and headloss

EPA-NET Workshop

Review In EPANET: valves are (links or nodes)? pumps are (links or nodes)? pipes are (links or nodes)? reservoirs are (links or nodes)? demands are supplied at (links or nodes)? what is meaning of negative demand? where are elevations specified? how is pump performance specified?

Step-by-Step Example

EPANET Example Network Layout

EPANET Example Demands