Post on 24-Apr-2020
Systems that need a Lift
PUMP TYPESSump
Clean Water Only
Effluent Multi stage
Single stage
Sewage Grinder
Pumping to Gravity Distribution When STA is at higher elevation than septic tank
Pump Sizing
TDH
Set by Location
Impacted by flow
GPM
15 - 45 gpm
Dose to Gravity
Do not pump downhill
Does not result in uniform distribution in laterals
Can discharge to either parallel or sequential
network.
Think about this before installing…..
Distribution Box and Tiered Trenches
Pressure Manifold Pressure DistributionDesigned to distribute effluent uniformly over infiltrative
surface of receiving component.
Pumping to Pressure
Distribution Pressure Distribution Uses a network of small diameter pipe [1”-2”] and
small orifices [1/8”-1/4”]
NSFC
The ‘Right’ Pump for
Pressure Distribution TDH
Set by
Elevation
Flow Rate – Pipe Diameter
Distribution
GPM
Set by
Number of orifices
[6- 10 sqft per orifice]
Orifice size
Operating pressure
System Curve
Pump Curve
System Curve
How Pump Works
Elevation Head
Pipe Friction
Manifold Loss
Where it Operates
Pump Efficiency
Pump & System Curves
0
20
40
60
80
100
120
5 10 15 20 25 30 35 40 45 50 55 60 65
gpm
tdh
0.5 hp Pump
1.0 hp Pump
System Curve at El 0
System Curve at El +5
Pressure Distribution Design considerations
May use flow-splitting devices to minimize pump size
Pump Vault
Pumping from the Source
The pump
Sizing
Location
Maximum Volume The floats
The Electrical
The controls
The Sump Venting
Outside: In the System
Pump Applications Media Filter
Pump Tank
What size tank?
Capacity Dose volume
PLUS
Storage
Or Two Pumps Replaces storage
Every Pump Should Be:
Accessible
Replaceable
Wired Properly
Elevated
Controlled
Accessible Access from surface
Under the manhole
Manhole to the surface
Quick disconnect
Not Fernco
Reachable
Within 20” of the surface
Control Panel
Line of Site
Nuisance
Replaceable
Removable
Pump
Floats
Ability to lift the pump
Reconnecting the pump
Electrician?
Reconnecting the controls
Pump Wiring
In & out of the Tank
Conduit [1”-2”]
Safe in the Sewage
environment,
EXCEPT FOR
SPLICES!!
Electrical tape is not
watertight
Electrical components
sealed and watertight?
Venting
Be careful
All electrical should be sealed
If necessary vent thru a filter for odors
Electrical
The right size wire
Pump size [hp]
Distance
Separate Circuits
Pump
Alarm
Wiring
Be careful of
the power
Hard conduit
around the tank
Pump should be:
Elevated off
bottom
Storage
Covered
with effluent
Protection
Pump Basin [Elevated]
Make sure the floats do not rest on the basin lip
Controlled Demand
Piggy back
Floats
Timed
Demand Dosing
Dose occurs when sufficient volume of effluent has
been collected.
Dosing frequency depends on how much wastewater
is being generated.
There is no control on how much effluent is being
dosed daily.
Demand
Dosing Two or Three
floats
On level sets the
volume
Check valve holds
effluent in the piping
Off level above the
pump
Water Level SensorsFloat
Pressure
Wet
The Floats [Controls] Activation angle
Voltage
Float Switches
Mercury Float Switch Mechanical Float Switch
Sensor Attachment
Sensor can be:
Tethered to float tree
Weighted tether from riser
Attached to bracket
on riser
Float Tree Dose Volume (DV)
Maximum~
Daily flow ÷ 4
600 ÷ 4= 150 gal
Minimum~
4 times piping volume*
Example:
3 trenches w/40’ of 1.5” pipe
3 x 40’ x 0.10 gal/ft
12 gal x 4 = 48 gals
* Some sources say 5X piping volume
Drawdown and Dose Volume
Drawdown (in) = Dose Volume
(gallons) ÷ GPI (gallons per inch)
of drawdown
Where:
GPI = Area of dosing tank or
chamber (in square ft) x 0.083 ft
x 7.5 gal/ft3
Note: 1” = ½ ft or 0.083 ft
Area = length X width (of dosing
chamber or dose tank)
Calculating Drawdown
Surface Area
Rectangle: 4’ x 7’ tank
L x W = Area
4’ x 7’ = 28 ft2
Circle: 4’ diameter
Radius is half of diameter 4 ÷
2 = 2’
Π x [radius]2= 3.14 x r x r
3.14 x 2 x 2 = 12.5 ft2
Top View
Length= 7’
Diameter = 4’
Radius = 2’
Width= 4’
Gallons Per Inch Area x 0.083’ x 7.5 gal/ft3
= gal/inch
28 ft2 x 0.083’ x 7.5
gal/ft3= 17.5 gal/in 12.5 ft2 x 0.083’ x 7.5
gal/ft3 = 7.8 gal/in
Plan View
Dose Volume (DV)
Drawdown (in) = Dose Vol. ÷ GPI
Dose volume ~ 100 gal
Drawdown = 100 gal ÷ 17.5 gal/in
5.7”
Nominal Pipe Size (in)
Water Content (per ft. pipe)
VolumeWeight (lbs.)
(cu. in) (gallons)
1/4 0.59 0.003 0.02
3/8 1.33 0.006 0.05
1/2 2.36 0.010 0.09
3/4 5.30 0.023 0.19
1 9.43 0.041 0.34
1 1/4 14.7 0.064 0.53
1 1/2 21.2 0.092 0.77
2 37.7 0.163 1.36
2 1/2 58.9 0.255 2.13
3 84.8 0.367 2.31
4 150.8 0.653 5.44
5 235.6 1.02 8.50
6 339.3 1.47 12.2
8 603.2 2-61 21.8
10 942.5 4.08 34.0
12 1357.2 5.88 49.0
15 2120.6 9.18 76.5
Typical Pipe Volume Table Without a Check Valve 100 gal Pumped Volume= PV
Must subtract the drain back
Drain back = Volume of pipe
Drain back = Volume/LF x LF of pipe
Ex: 60’ of 2 inch pipe
Drain back = 60 ft x 0.17 gal/ft = 10.2 gal
Dose Volume = PV – Drain back
DV = 100 gal – 10.2 gal = 89.8 gal
that reaches the STA
Floats
Pump Cover ~ Off
4”+ 14” + 2”= 20”
Dose~ On
5.7”
20”+5.7”= 25.7”
Alarm
3”
25.7”+3”= 28.7”
Float Switch or
Piggy back
Low cost
Controlled by
volume only
Easy wiring
Timers Timed Dosing
A timer controls the number of doses per day and the
dose volume.
Will allow only a certain amount of effluent to be
dosed daily.
Protects downstream components from overloading.
Useful for controlling surges or big-flow days.
Functions Off [Float]
Turns timer off
On Timer operates the
pump
Alarm Turns on the alarm
Peak Enabler Changes the dosing
frequency (PLC)
Alarm
Audible
Visual
Lateral Cleanouts
Single Pass Sand Filter With
Discharge Pump
Geo-FabricLoamy Sand or
Decorative Rock
Stone (2" Over Pipe)
Filter Sand (See Specifications)
Pea Gravel
30 MIL PVC Liner
Pump Basin Sand
Backfill
2" Sand
Leveling Layer
PVC Lateral w/
Orifice Shields
Flushing
ValveValve Box
Liner Support
(1/2" Plywood)
To Soil
Optional Lateral/Flushing
Valve Connections
6"
6"
2'
6"
Sweep 2 - 45°
Lateral End Clean-Out Types
Straight ends Threaded caps
Ball valves
Sweep 90 degree elbows (electrical sweeps are pressure rated)
2 - 45 degree elbows
Equipment Selection
Don’t let supplier select your equipment
Better to talk to manufacturer
DON’T change components specified in design
without consulting the designer; you are accepting
liability
Questions?
Low-Pressure Distribution
DrainfieldShallow Narrow Drainfield
Orifices in Laterals:
Lay out and number the laterals
Use a string line to mark pipe
Pay attention to orientation and spacing
Location of first/last orifice in each lateral may vary
Drilling Orifices
Use a new bit
Use the correct size
Keep the drill
vertical
Don’t “wallow” or it
will be too large
Orifice shape
affects flow
Pressure System Orifice Shields
Keep media away from orifice
Follow manufacturer recommendations
Spacing and size of delivery devices
Little to n
o s
lope
Level sites: orifice size and spacing is typically the
same in each lateral
Slo
pe
Spacing of delivery devices
Sloping sites: spacing may vary to maximize uniformity
CAUTION: if diameter varies, smaller orifices may clog
more quickly
Balancing Unlevel Distribution
Goal:
Splitting the flow equally
Level ~Easy
Problem
Separate Pieces
Typically equal
Separate pumps
Alternating
Splitter valves
Hydro Splitter
(ADV)Using Valves
Balancing the pressure
Flow Regulating Valves
Adding one increases friction loss
Globe valve is best but most expensive
Gate valve is better
Should NOT be a ball valve
Valve Boxes
Design Orifice spacing and sizing
Sprays to the same height
Lower laterals
Higher pressure
Smaller holes
Larger spacing
Questions?