AST PolyGeyser User manual

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New Orleans, LA 70121
Phone [phone]
Fax [phone]
[email protected]
www.ASTfilters.com Updated 08/10/16 V1-AST

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Table of Contents
Introduction to the HPPG Series................................................................................................................... 2
Operation...................................................................................................................................................... 2
Backwash Operation Overview..................................................................................................................... 0
HPPG Bead Filter Major Components........................................................................................................... 3
Installation .................................................................................................................................................... 4
Pump Configuration.................................................................................................................................. 4
Airlift Configuration .................................................................................................................................. 6
Backwash Air Pump....................................................................................................................................... 8
General Setup Directions ........................................................................................................................10
Adjusting your Backwash Frequency ...................................................................................................... 11
Sludge Drainage Assembly.......................................................................................................................... 14
Air Pump Requirements for Backwashing .............................................................................................. 15
Backwash Frequency............................................................................................................................... 15
Troubleshooting (Filter Function) ...............................................................................................................17
Trouble Shooting for Recirculating Aquaculture Applications............................................................ 20
Sulfide Production.......................................................................................................................................21
Filter Acclimation ........................................................................................................................................ 22
Appendix A: The Science behind Bioclarification........................................................................................27
Clarification............................................................................................................................................. 27
Biofiltration .............................................................................................................................................29
Warranty. .................................................................................................................................................... 32

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Introduc�on to the HPPG Series
The High Pressure PolyGeyser®(HPPG) blter series is the newest addon to Aquaculture Systems
Technologies’ line of bead lters. Patented ( U.S. Patent #9,227,863 Patent Pending , European
Patent #0977713B & Canadian Patent #2,287,191) fully exploits the biolm protecon provided by our
Enhanced Nitricaon (EN) Bead Media in a durable berglass hull. Designed as “bioclaris” capable
of performing both biological and mechanicalaon, PolyGeyser®Bead Filters are capable of handling
biological loads 50% to 100% higher than our Bubble Bead or Propeller Bead Filters equipped with
standard bead media. Addionally, the PolyGeyser®Bead Filters are virtually immune to clogging and
caking, since they are backwashed pneumly at a high frequency. These High Pressure PolyGeyser®
(HPPG) Bead Filters recycle their own backwash waters. The HPPG lters are the bioclari of choice
for commercial aquaculture and wastewater applicaons dealing with high organic loads.
Opera�on
The PolyGeyser®Bead Filter stands apart from AST’s other Bead Filter technologies primarily through its
automneuma backwash mechanism. Water is introduced below the bed of packed EN bead
media and travels upward through the ltraon chamber where mechanical and biologicalltraon
takes place. Simultaneously, air is slowly introduced into the air charge chamber at a constant,
predetermined rate to achieve the desired backwash frequency. Once the charge chamber has reached
capacity, the pneumac trigger res, releasing the entrained air from the charge chamber below the
media bed. The sudden release of air from the charge chamber causes the beads to mix, roll and “drop”
as the air agitates the beads.
The circulaon pump/airlioperates connually, which ensures that ther chamber begins relling
immediately aer each backwash event. This causes the beads to oat upward and reform as a bed.
During the recharge cycle (a few hours), suspended solids in the trapped backwash waters sele into the
sludge storage chamber for later disposal via the sludge drain valve (usually every 3 days- 1 week). At
the same me, the claried backwash waters are passed slowly through the bead bed again eliminng
any backwash water losses.
The eliminaon of water loss associated with backwashing is a key element in this new technology. In
most applicaons, dozens of backwash sequences can be automly executed before sludge removal
is required. There is no water loss associated with the backwash process and the water loss associated
with sludge drainage is negligible. This strategy is paularly advantageous for marine systems, where
the loss of saltwater must be minimized.

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The pneuma�c strategy breaks the linkage between backwash frequency and water loss and allows the
nitrifica�on capacity of the unit to be fully utilized. Frequent backwash sequences have proven
advantageous for op�mizing the nitrifica�on capacity of the unit. Numerous gentle scrubbing cycles
promote high rates of nitrifica�on by maintaining a healthy thin biofilm on the bead surfaces. Typical
backwash cycles occur once every three to six hours. In recircula�ng bioclarifier applica�ons, where the
High Pressure PolyGeyser
®Bead Filter operates concurrently as a clarifier and biofilter, total ammonia
nitrogen (TAN) levels below 0.3, 0.5 and 1.0 mg-N/l can be expected at feed loading rates of 0.5, 1.0 and
1.5 pounds feed per cubic foot of EN bead media (8, 16 and 24 kg-feed m-3 day-1), respec�vely.
Table 5. High Pressure
PolyGeyser
®Bead Filter Specifica�ons

Backwash Operation Overview
The PolyGeyser filter is a breakthrough in filter technology. It features an advanced auto-pneumatic
backwash mechanism. Water enters below the bed of enhanced nitrification media and travels upward
through the filtration chamber where mechanical and biological filtration take place. Simultaneously, air
is introduced into the charge chamber at a constant predetermined rate to achieve the desired
backwash frequency.
Once the charge chamber has reached capacity, the pneumatic trigger fires. This releases the entrained
air from the charge chamber below the bead bed. The sudden release of air from the charge chamber
causes the beads to mix as the air agitates the beads. As the beads drop, the bead bed expands
downward while water rushes downward through the expanded beads, sweeping the solids away and
into the air charge chamber.
In the chamber, the solids settle out from the backwash waters and are later removed from the filter.
Essentially, this type of filter recycles the backwash water while concentrating the waste products so
that you have extremely low water loss while maximizing the nitrification capacity.
Frequent backwashing has proven advantageous for optimizing the nitrification capacity of a
Polygeyser® filters. Numerous gentle scrubbing cycles promotes a higher rate of nitrification by
maintaining a healthy thin biofilm on the surface of the bead media. Typical backwash cycles occur every
3-6 hours.

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2
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3
HPPG Bead Filter Major Components
Table 6. Major Component List –Basic Configuration
Descriptor
Function
Comment
A
Inlet
Directs flow into filter via the
diffuser
B
Screen
Passes water while retaining the
beads in the filter
C
Outlet
Directs the filtered water into the
return lines.
Multiple outlets are generally used for
airlift models to lower water velocity and
hydraulic friction
D
Bead Bed
Captures suspended solids while
providing surface area for biological
processes, such as nitrification, used
to restore water to a pristine
condition
The beads float to form tightly packed
granular bed ideal for physical and
biological filtration. Beads are typically 2-3
mm in diameter.

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E
Charge Chamber
The air tight cone defines the charge
chamber while forming a conduit for
water transmission into and out of
the charge chamber
In this design series, the charge chamber is
wrapped around the centralized conduit
which re-suspends and aerates sludge
during each backwash event
F
Air Inlet
Slowly fills the charge chamber with
air
Air is added at a slow rate so that it takes a
few hours to fill the charge chamber.
G
Trigger
Catastrophically releases air from
the charge chamber once it is filled
H
Diffuser
Redirects the incoming water
beneath the bead bed.
Hydraulically designed to minimize
turbulence that may erode the bed.
I
Sludge Basin
Provides for temporary sludge
storage.
The sludge that is released from the bead
bed during a backwash settles out of the
cone and charge chamber that can be
removed periodically as a thick sludge
through the sludge outlet.
J
Sludge Outlet
Facilitates the removal for thickened
sludge from the unit.
Sludge is typically concentrated to 10,000-
20,000 mg/L in the HPPG series.
Cap
Directs flow from the screen to the
Outlet pipe(s)
The cap assembly also includes gaskets that
seal the screen to the filter hull.
Installation
Installation will require that you hook up a water pump to circulate water through the filtration bed and
an air compressor to fill the charge chamber for the back wash sequence. Filters in the HPPG series are
most frequently paired with a low head centrifugal pump capable of delivering a high rate of flow at
relatively low pressures (5-10 psi). However, in commercial scale recirculating aquaculture
applications, the units can be paired with airlifts to minimize energy consumption. Use of airlifts,
however, generally requires lowering (burying) the unit so water can be filtered by gravity and then
airlifted back up. With total filtration head losses beneath 0.5 psi, use of airlifts can be attractive
whenever the physical configuration permits.
The backwashing air source must be matched with the circulation method you select. Simply stated the
air pressure must exceed the water pressure for air to flow into the unit.
Pump Configuration
A self-siphoning, above ground, centrifugal water pump can be used to circulate water through an
HPPG. The unit should have a water delivery capacity of 10-15 gallons per minute for each cubic foot of

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media at the operational pressure for the unit (typically in the range of 5-15 PSI). The shutoff pressure
off the pump should be less than 20 psi, or near 20 psi when a pressure relief is installed to avoid
damaging the HPPG hull.
HPPG Filter External Plumbing illustrates a typical plumbing arrangement. In most case the pump (9)
should be protected by a screen or an inline screen basket (10). Many pumps already have the inline
basket attached. A hard PVC couple (8) is placed immediately adjacent to the pump discharge to
facilitate pump replacement or servicing. A rubber or flexible couple should be avoided here, as they
are sensitive to pump vibration tend to work loose. This coupling is followed immediately by a
mandatory check valve (7) which prevents the backflow of beads into the pump during periods of
power interruption. If the pump’s flow capacity is significantly greater than the filters rating then a ball
valve (5) is then placed in line to allow the pump to be throttled to manage flow through the HPPG unit.
Alternately a “tee” can be placed at this location with two ball valves allowing for flow to bypass the unit
to a parallel use. You will find a 0-30 psi pressure gauge (3) will greatly facilitate the management of
the filter. High pressures are an indication to increase the backwash frequency. Finally, in situations
where either the water pump or the backwashing air pump have high shutoff pressures (>20 psi) then
a pressure relief valve must be placed immediately adjacent to the filter input to assure protection of
the hull. The pressure relief valve can be set to pop at 20 psi. All HPPG filters are pressure tested at a
higher pressure to ensure quality prior to shipping, but the operational pressures should not exceed 20
psi.

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Airlift Configuration
The HPPG series is equipped with an oversized screen and inlet/outlet plumbing to facilitate airlift
operation. Typically, the filter must be positioned next to the tank so that the screen is 12-15” below
the water level in the tank. The siphoning outlet pipes are then directed toward the ground to develop
pressure for the airlift operation. The discharge pipes are then curve back to the vertical draft tube. Air
is injected near the bottom of the draft tube to create a low density air/water mixture that is pushed
upward by the dense water in the siphon line. The elevated air and water mixture is then moved
horizontally to the tank.
Water Flow in an Airlifted HPPG: Water exits from the top of the filter, into the U pipe. Air injected into
the far draft tube pushes the water up and out of the pipe, back into the tank.

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Air Flowrate Calculations for Airlift Con guration
Table 8. Air Flowrate Calculaons
Model
Flowrate
(Qf, gpm)
Outlet
Pipe Size (in)
Flow
Velocity
(/s)
Screen
Level
(in)
Air Li
Requirement
(in)
Air
Injecon
Depth (in)
Air
Delivery
Pressure
(in)
Air Flowrate
(Qair, scfm)
(D
down
)
(D
li
)
(V
in
)
(Vli)
(H)
(L)
(S)
(L+S)
HPPG-10
150
4
6
3.84
1.69
83
12
48
60
41
HPPG-25
300
6
8
3.37
1.94
80
12
48
60
83
HPPG-50
750
8
12
4.86
2.17
111
12
48e
60
206

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Backwash Air Pump
Backwash air pumps are required to operate an HPPG filter. If you have not purchased a backwash
pump with your HPPG filter, you require a low volume continuous duty pumps that is sized to sustain
the appropriate backwash frequency for your filter model. The pump must also be compatible with the
pressure range that is appropriate to the filter. Noise will be generated by the pump, so placement
should be carefully considered. If the pump is placed outside or in a wet room, it should be properly
insulated from water and condensation.
The operational pressure for air injection into the charge chamber of a water pump driven HPPG filter
with a free discharge out of the outlet pipe should be in in the range of 4-6 psi if the backwash
frequency is set properly. At design flow rates about half of this pressure is attributed to the physical
depth of the air injection, the balance is attributed to baseline friction loss through the bead bed or
fittings. If the backflush frequency is set too low, the pressure loss across the bead bed will increase. In
the extreme, the hull pressure will be defined by the shutoff pressure of the pump. The air pump should
be sized to overcome this pump shutoff pressure. Ideally, the air pump and water pumped should be
matched with the air pump having a shut off pressure higher than the pump.
Injection pressures for HPPG airlift applications are controlled by the distance from the tank water
surface to the centerline of the horizontal pipe in the unit’s external trigger (typically a maximum of
about 100 inches or 4 psi). The air injection pressure in an airlifted HPPG does not vary much. An
operational pressure of 5 psi is sufficient.
A medium sized linear air pump is a good choice for airlift applications where backpressures on the
HPPG unit are minimized. These units operate by oscillating a rubber diaphragm that moves air through
a series of valves. These pumps are readily available in weather resistant configurations used for pond
and home packed wastewater treatment units. The flow rates delivered by these blowers are generally
in excess of the backwashing needs, so the unit should be selected based upon its maximum operational
pressure. The larger liner pumps have shutoff pressures in the range of 10 psi which is suitable for most
HPPGs where the unit is not back pressured by downstream devices. Linear air pumps contain a
replaceable rubber diaphragm that will ultimately fail (every 2-3 years depending on the model and
pressure).
A small oil free continuous duty piston pump with an operational pressure rating of about 20 psi is most
ideally suited for delivering air for a wide variety of HPPG applications. These units have small pistons
that are driven directly by a small electric motor. Producing only moderate amount of air, these unit are
recognized for sustained operation at the moderate pressures demanded by HPPG applications.
Capable of delivering a continuous supply of air at the HPPG maximum hull pressure of 20 psi, these
units also display relatively high shutoff pressures that are compatible with a wide variety of pumps.
The air volume produced by this unit is reduced and thus the air delivery capacity should be matched to
the HPPG. These units are most often sized to serve the air demands of a single HPPG unit.
Rotary vane compressors operate in a pressure range (0-15 PSI) well above the more widely recognized
rotary vane blower (0-3 psi). A rotary vane compressor consists of a motor that spins a set of inclined

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high speeds blades that compress and accelerate air into the distribution system. They are capable of
producing large volumes of air in the 10 psi range. These units are typically the air supply of choice for
facilities containing multiple High Pressure PolyGeyser®filters.
The common oil-less shop compressors can be used to backwash a HPPG unit. Commonly capable of
producing pressures in excess of 100 psi, these units are capable of overcoming any pressure produced
by a water pump. These units are powerful piston units that produce a relatively small volume of air at
extremely high pressures. Normally installed with the delivery pressure regulated down to 20 psi, these
compressors can be set to match virtually any water pump. Inexpensive shop compressors are not
designed for continuous duty. A compressor tank is usually associated with the compressor unit and
the motor operates intermittently to maintain the tank pressure. These units should be sized with a
delivery capacity 5-10 times higher than the backwashing air capacity to assure the compressor operates
only periodically. (Note: These compressors are typically rated in terms of cubic feet per minute at
100+ psi whereas backwash demands are rated in cubic foot per hour at 20 psi). Shop compressors are
generally noisy and are poorly designed for a wet environment. Under normal circumstances, the air
pressure delivered to a unit does not influence the pressure experienced by a HPPG hull. Air input into
the unit merely displaces water; there is no potential for internally damaging the unit by over pressuring
the charge chamber. However, the pressures generated by a poorly adjusted shop compressor (I.e. the
discharge pressure regulator is set too high) are clearly capable of catastrophically cracking hull rated for
20 psi. This can occur if the unit is “dead headed” by closure of an outlet line trapping the pressure
between an inlet check valve and the closed outlet valve. Thus, units employing shop compressors for
backwashing must be equipped with a pressure relief valve on the air line or a water line immediately
adjacent to the hull on the influent or effluent side.
Pump
Typical
Pressure
Range
Comments
Linear Air
0-10 psi
Excellent for backwashing of filters that are nor back pressured
by downstream constrictions, may be over powered by shutoff
head of water pump so should be protected by check valve.
Energy efficient.
Piston
0-30 psi
Generally suitable for all HPPG applications. Capable of
generating pressures in excess of hull pressures thus cannot
be overcome by properly sized water pump.
Rotary vane
compressor
0-15 psi
Suitable for low pressure airlift applications and simplified
pumped configurations. Produce volumes sufficient to
Shop
0-150 psi
Oil free shop (piston) compressors with tank work well as a
backwash air supply provided they are sized large enough to
provide for extended cycle time. Tend to be noisy and over
pressurized, but, inexpensive.

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General Setup Directions
1. Prepare your filter’s location. The High Pressure Polygeyser® must be
installed on a level surface to backwash properly. The unit is designed to
tolerate only about ½ inch of vertical displacement edge to edge across its
width in any direction. Failure to properly level the may cause the unit to
prematurely backwash (i.e. before the charge chamber is filled) or fail to
backwash as the air in the charge chamber bypasses up the center of the
cone.
If using an airlifted configuration, the screen should sit 12-15 inches below
the source tank water level. If this requires placement of the HPPG hull
partially below ground, buoyancy calculations should be undertaken. High
ground water conditions or simple flooding of the unit can generate
buoyancy force of several thousand pounds. Maximum buoyancy occurs
when an empty filter is flooded externally to the screen elevation. The
units can be held down by a concrete collar placed around the upper dome.
A fully buried unit, in the worst case, would require in excess of 2 cubic foot
of concrete per cubic foot of beads in the filter.
2. Connect your inlet and outlet plumbing. See pump or airlift configuration
for detailed plumbing directions for your choice of setup.
3. Attach your backwashing air pump. Whenever a water pump is employed,
the backwash air pump must be protected by a check valve that prevents
backflow into the air delivery system. Without the check valve, the air
pump will be damaged the first time it is accidently turned off or
mechanically loses pressure.
In air lift applications, the backwash air pump may be protected by
elevation only. Placement of the air a few feet vertical above the tank
water level is sufficient to protect the pump.
4. Decide how to deal with drained sludge. You can place a bucket under the
drain valve, or run a PVC line to wherever the sludge should drain. Sludge

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can be used as fertilizer for plants. In aquacultural applications, sludge
production is estimated at 3-6 gallons per cubic foot of beads per day at
design capacity (1.5 lbs feed/ft3-day). Sludge handling should be sized for a
generation rate of about 10 gallons per cubic foot of bead per day. See
sludge drainage assembly for more details.
5. Once your unit is plumbed, fill it, turn on the water pump. Set the
backwash feed rate at the maximum to achieve the highest backwash rate
attainable with your set up (possibly as much as once every 15 minutes).
Let the unit operate in this manner for 12-24 hours, more if possible.
Under normal operation the bead bed is formed by simple buoyancy. There
is one screen in the head designed to constrain the beads. The unit’s
pneumatic and hydraulic behavior is designed to substantially confine the
beads to filtration bed. During shipping, a substantial proportion of the
beads fall into the charge chamber where they are trapped (by buoyancy)
in the charge chamber. So when you first fill the HPPG, perhaps fifty
percent your filtration bed is in the lower chamber. The unit’s trigger is
designed to pass beads from the lower chamber, but only at a hand full per
cycle. So the system must be operated at a high backwash frequency for a
time to readjust the unit’s internal balance.
6. Adjust the backwash pump’s air flow down after the first day, so that the
filter backwashes two four to four times daily. Your application may benefit
from adjusting the backwash frequency up or down depending on your
loading.
7. Now look through the port hole that is positioned on the upper dome of
the HPPG unit. This is what a clean bead looks like. These beads will
become beige with nitrifying bacteria over time. If beads appear very
brown or clumped, increase the backwash frequency.
Adjusting your Backwash Frequency
Your PolyGeyser®filter employs a static bed of beads to capture suspended solids and/or provide
substrate for development of a biofilm to remove targeted dissolved pollutants (organics, ammonia).
After time, the accumulation of solids in the bed begins to reduce the hydraulic conductivity of the bed

12
and the flow passed through the unit declines. Each application has its optimum interval for
backwashing. In some cases, an extended backwash interval produces optimum performance and in
others, and extremely short backwash interval is best. In broad terms, short backwash intervals (<6
hours) are associated with heavy loads. Best performance for lightly loaded applications is usually
associated with extended backwash intervals (>12 hours).
In recirculating aquaculture or wastewater clarifier applications where the HPPG is used solely as solids
capture device reducing suspended solids levels, a high backwash frequency generally produces the
greatest mass removal rate. In these applications, the targeted particle size range is usually of the order
of >50 microns. Organics in the water will create a sticky surface that tends to stick particles together on
the bead surface. Internal settling after a backwash is rapid, and backflush frequencies can be short
(<hour) without adversely filter performance. A good starting point for the backwash interval in a
recirculating clarifier application is 3 hours. If a decline in flow through the filter (or an increase in hull
pressure) is noticeable, increase the backwash pump airflow for more frequent backwashes.
If the application is focused on water clarity for display aquaria or zoo applications, then the HPPG
should be used as a clarifier focusing on small suspended particles. A clean bed of standard sized beads
has relatively poor single pass removal efficiency (20%) for particles below 20 microns. Single pass
capture of these particles is dramatically improved (>40%) once the bed begins to fill with biological or
mineral solids. Excessive backwashing should be avoided in clarifier applications. Lightly loaded HPPG
applications with a focus on water clarity (reduced turbidity) are generally associated with extended
backwash intervals, perhaps, twice a week. In lightly loaded application seeking high water clarity,
start with a backwash interval of once a day. Increase the backwash frequency (turn up the air) if the
flow through the filter declines significantly as this is a sign solids are not being backwashed enough for
your application. For single pass applications, the best water clarity is always obtained with reduced
flow and high pressure drop across the bead bed.
In recirculating applications, the benefits of increasing single pass efficiency by flow reduction are offset
by the reduction of number of filtration passes. The optimum in a recirculating application is normally
found at an interval that high pressure drop across the bed and high flows, a zone of moderate pressure
loss across the bed.
Clarifier applications are relatively insensitive to backwash interval, HPPG biological function can be
dramatically influenced by the backwash frequency. Here backwashing influences several factors
(Table 6). Optimization of backwash frequency is application specific and your HPPG allowing process
optimization under both aerobic and anaerobic conditions across a wide range of loadings and targeted
substrates.
Table 6. Backwashing interval impacts biofiltration through several factors.
Factor
Importance
Comment
Biofilm thickness
Controls the mass of bacteria working

13
Controls the rate limiting nutrient
transport into the biofilm
Water flow
Controls the targeted substrate
concentration adjacent to the bead
Controls oxygen transport to the biofilm
Controls turbulence at the biofilm water
interface
Best biological treatment is
associated with the highest
achievable flows
Mean cell residence
time (MCRT)
Determines the type of bacteria and
protozoa that will be found in the filter.
In recirculating aquaculture applications, PolyGeyser® are widely used as bioclarifiers simultaneously
removing suspended solids, dissolved organics, total ammonia nitrogen (TAN) and nitrite nitrogen. Here
the limiting process step is usually TAN conversion since the TAN must diffuse into the biofilm prior to
conversion. Carbon to nitrogen ratios are relatively stable being fixed by the protein content range of
the feed. Backwash frequencies must be increased with organic loading (pounds feed/cubic foot beads
per day) to offset the smothering effect of heterotrophic bacteria on the slower growing nitrification
bacteria. The general guideline for backflush frequencies is illustrated in Figure__.
In recirculating applications, the backwash tuning success is reflected in the TAN and Nitrite
concentration. It is not uncommon to see the TAN concentration reduced by 50% with a small change in
backwash frequency. The limits of backwash frequency are defined by the nitrite oxidizing bacteria
(NOB). Backwash too often and the NOB are “washed out” as the biofilms mean cell resident time
(MCRT) drop; Wash too slowly and oxygen transport into the biofilm will drop, triggering or reversing
the NOB oxidation process. So watch for the telltale rise in nitrite as you optimize backwash
frequencies.
In domestic wastewater treatment where biological oxygen demand (BOD5) and Total Suspended
Solids (TSS) are targeted, frequencies tend to be high (once every 3 hours) to maintain hydraulic
conductivity of the bed. The backwash frequency for biological operation is largely controlled by the
organic loading (kg-BOD5/m3of bead-day). Failure to backwash frequently enough leads to clogging of
the bead bed as heterotrophic bacteria attack readily biodegradable organics.

14
Sludge Drainage Assembly
Sludge Drainage Assembly, recommended Plumbing: PVC pipe, 90° elbow, Tee. Ball Valve is
included. Pipe clamp recommended.
Connect drain line to the installed bottom valve for sludge drainage. AST recommends that the
sludge pipe connect to a 90° elbow, pointing up. The vertical pipe should come to a tee
positioned on the midline of the inlet to prevent bead loss when draining the sludge. Make sure
the sludge pipe is securely attached to avoid breakage.

15
Air Pump Requirements for Backwashing
The Charge Chamber capac for PolyGeyser
®Bead Filter ModelPPG
have axedeach volume of air to charge the chamber. Once thivolume imet, the trigger
re and ter will backwh.
Inelecng an appropriate air pump for theytem, the air ow capacity (cor lpm) required to eect
backwhet the ded intervaland air delivery pr mut be taken into conderaon. If the
lte operated with a water circulaon pump, the air delivery pr mut exceed that of the water
pump to prevent accidental ooding of the air pump, which may present an electrical hazar d.
Addonally, a check valve d be inled in the air line to preventooding of the air pump in the
event of a power outage and to protect the air pump in c of exceve pre development in the
lter.
We recommendng an air pump capable of producing the mot frequent backnterv that may
be required. Theow rate can then be regulated by ining an air ow meter, with a built-in regung
valve. AST o an airow meter kitwhich includeAcrylic Air Flowmeter, a Labcock Valve, a
Pre Gauge, a Nylon Spacer andt, Barb Fingand other PVC Fing. trongly
recommended for air pumpthat do not have built-in air adjutment on them. Adjug the air ow
directly impac the frequency of the filter backwh.
Selecon of proper backwaair pump of concern when operang in the airlimode, the
yem operateat a very low head (36-48” / 92-120 TD). Several commercially available air pump
are capable of delivering the required volume and meeng the prdemandor ngle unit.
owever, theelecon of air pump ulmately dependent on the elecon of water pump
Backwash Frequency
Figure A pentthe relaonip between air delivery to the charge chamber and backwh frequency
for the vaPG mode. Thee airow rat areed in cfm at the prere of delivery they
would appear on a rotameter connected to the model. Aicompble. The volume of air required
to iniate a backn anPPxed by dgn, but, the exact backnterval produced can
be inuenced byre pa on the hull. If the hullre enicantly during the ltraon
interval, then the actual backwh interval will longer (by a few minute than the table ind