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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 (BOD

5

) 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-BOD

5

/m

3

 of bead-day). Failure to backwash frequently enough leads to clogging of 

the bead bed as heterotrophic bacteria attack readily biodegradable organics.    

 

 

 

 

Summary of Contents for PolyGeyser

Page 1: ...108 Industrial Avenue New Orleans LA 70121 Phone 504 837 5575 Fax 504 837 5585 Info astfilters com www ASTfilters com Updated 08 10 16 V1 AST ...

Page 2: ...ir 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...

Page 3: ...a on chamber where mechanical and biological filtra 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 fires releasing the entrained air from the charge chamber below the media bed The sudden release of air from the charge chambe...

Page 4: ...a 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...

Page 5: ...m 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...

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Page 8: ...ts 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 filtratio...

Page 9: ...he 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 d...

Page 10: ...ads 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 pres...

Page 11: ...o 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 th...

Page 12: ...f 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 Ddown Dli Vin 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 ...

Page 13: ...onal 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 d...

Page 14: ...ressure 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 hu...

Page 15: ... 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 ...

Page 16: ... 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 f...

Page 17: ... 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 lo...

Page 18: ...ophic 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 n...

Page 19: ...mmended 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 ...

Page 20: ...cludes an Acrylic Air Flowmeter a Labcock Valve a Pressure Gauge a Nylon Spacer and Fasteners Barb Fi ngs and other PVC Fi ngs This is strongly recommended for air pumps that do not have built in air adjustment on them Adjus ng the air flow directly impacts the frequency of the filter backwash Selec on of proper backwash air pumps is of less concern when opera ng in the airli mode since the system ...

Page 21: ...s for targeted feed rates These recommended intervals should be considered starting points as true optimums are defined by temperature feed compositions and recirculation rates Under light loading conditions 0 5 lbs feed ft3 beads day you will find the HPPG provide excellent water quality across a broad spectrum of backwash frequencies Under heavily loadings 1 5 lbs feed ft3 beads day the rate of ...

Page 22: ...ge your trigger is blocked or partially blocked You have a dysfunctional trigger and the unit is not dropping properly See the section on the air burps 4 If your unit washes quickly 5 seconds but fails to drop look through the port hole you may be flooding the filter with excessive flow during the wash Check if your water pump sized properly for the HPPG model The flow coming out of my HHPG is dra...

Page 23: ...ure should restore immediately b If you have an inline screen with a clear top look for bubbles in the screen compartment IF there are a lot of bubbles present the air may be breaking the centrifugal action of the pump i Is there an air stone or packed column discharging air bubbles where they can be drawn in to the pump ii Check the seals on all threaded PVC pipe fittings on the suction side of t...

Page 24: ...ys undermined the backwashing strategy and should be corrected 1 If you are accelerating the wash sequence by dramatically increasing the rate of air input then reduce the rate of input It takes several seconds for a trigger to respond to a change in air level in the charge chamber This causes a lag time between filling the chamber and trigger release If you put the air in too fast then the chambe...

Page 25: ...HPPG stinks like rotten eggs This is part of the price paid for water conservation Organically rich sludge decaying in the absence of oxygen will smell like rotten eggs as sulfur is reduced This is a transitional problem Once the sludge is exposed to oxygen the smell will disappear 1 Try increasing your backflush frequency 2 Discharge your sludge though a hose that will prevent exposure to the air...

Page 26: ...rite levels may also occur if your total alkalinity as CaCO3 drops below 80mg l We recommended you maintain your alkalinity at 100 200 mg l as CaCO3 at all times If you experience low alkalinity simply add baking soda to the filtration system periodically to maintain proper levels Sodium bicarbonate is not suitable for aquaponics applications because sodium can harm plant development and growth Ap...

Page 27: ...uced and begin to accumulate When the power restores circulation sulfide can be smelled for the first minute The sulfides could potentially cause damages to aquatic species in the receiving tank or pond So as a precaution In cases of prolonged power interruption divert the initial flush of water away from ponds or tanks containing sensitive aquatic species In summary sludge digestion does occur in...

Page 28: ...lters will begin capturing suspended solids immediately because that is primarily a physical process that is not dependent on the development of a biofilm The biofilm for biological filtration will take a few weeks to develop if it is not introduced into the system via established media The heterotrophic bacteria will grow rapidly and quickly attach themselves to the beads The nitrifying bacteria ...

Page 29: ...age of acclimation is critical because during this period populations of bacteria which can effectively attack the specific waste produced by the animals become established and these bacterial populations adjust to operate under the water quality conditions and temperature regime found in your system This unique culture of bacteria will remain in the biofilter for years if maintained Table 3 summa...

Page 30: ...e domestic Koi or goldfish are good choices if fish are used However it is important that the fish or animals used during acclimation are disease free so as not to infect your high quality fish later These animals can tolerate short term exposure to TAN and nitrite levels of about 5 mg N l without harm if you keep the pH between 7 5 and 8 0 and add some sodium chloride rock salt or calcium chlorid...

Page 31: ...cclimation will probably occur without noticeable peaks The heights of the acclimation peaks are actually controlled by the density of fish in the system not by the size of the biofilter That is the nitrite peak in a system with a fish density of 0 25 pounds gallon will display a peak concentration one half as high as a system with a density of 0 5 pounds gallon Table 4 summarizes additional metho...

Page 32: ...ditions Bead filters capture solids through four identifiable mechanisms Table 1 With the exception of adsorption the solids capture mechanisms are physical in nature and are common to all types of granular media filters As a general observation the filters seem to control fine colloidal particles best with some biofilm development This suggests that the biofilm absorption process is an important ...

Page 33: ... beads and are not removed In sufficient quantity these materials will eventually foul the bed requiring media replacement Bead filters are also not well suited for the clarification of waters suffering from mineral turbidity problems caused by fine clays or other colloidal particles Lacking good biofilm development the mechanisms for the capture efficiencies are unacceptably low Finally the bead ...

Page 34: ... classifications of bacteria heterotrophic and nitrifying that are of particular interest Table 2 The two bacteria co exist in the filter and understanding their impact on each other as well as on the filter is critical Figure 2 The bacterial film that coats each bead contains the nitrifying bacterial population Heterotrophic bacteria also form a thin biofilm layer on each bead The nitrifying bact...

Page 35: ...s will quickly dominate the bead bed overgrowing the slower growing nitrifying bacteria and consuming tremendous amounts of oxygen The second yet more important classification of bacteria is the nitrifying bacteria These bacteria are specialists extracting energy for growth from the chemical conversion of ammonia to nitrite and from nitrite to nitrate Nitrate is a stable end product which although...

Page 36: ...ds that characterize and organic waste This an oxidation step that releases ammonia whenever a nitrogenous compound is encounters Heterotrophic bacteria use oxygen and release carbon dioxide but have little effect pH or the bicarbonates in the system The AOBs in system then initiate the first step in the nitrification process by the oxidation of TAN to nitrite This process consumes both oxygen and...

Page 37: ... only to the original purchaser This warranty is void if the items are damaged by negligence or accident after purchase used for other than the intended purpose altered repaired at other than an authorized service center or used with other items that affect the integrity performance or safety of these items Liability does not cover indirect or consequential cost including materials lost labor or i...

Page 38: ...let Coupling Outlet Pipe Inlet Valve Sludge Drain Valve Estimated Sludge Water Loss Max Opera ng Pressure Shipping Weight 1 HP Compressor pump 100 150 gpm 10 4000 3 Fipt 1x 3 Fipt 3 Fipt 1 25 Fipt 10 30 gallons 20 PSI 750 Lbs Custom Orienta on available STANDARD ORIENTATION Trigger High Trigger Low Window Sludge Drain and Inlet Outlet HPPG 1O SPECIFICATIONS ASTFILTERS COM 84 82 75 5 44 28 5 51 5 4...

Page 39: ...let Coupling Outlet Pipe Inlet Valve Sludge Drain Valve Estimated Sludge Water Loss Max Operating Pressure Shipping Weight 1 HP Compressor pump 150 225 gpm 15 6000 4 Fipt 1x 4 Fipt 4 Fipt 1 25 Fipt 20 40 gallons 20 PSI 1200 Lbs Custom Orienta on available STANDARD ORIENTATION Trigger High Trigger Low Window Sludge Drain and Inlet Outlet HPPG 15 SPECIFICATIONS ASTFILTERS COM 84 81 75 5 44 28 5 53 4...

Page 40: ... Shipping Weight 5 HP 18 8 10 9 4 250 375 gpm 25 10000 6 Fipt 2x 6 Fipt 3 Fipt 1 5 Fipt 30 60 gallons 20 PSI 1508 Lbs 1700 Lbs 104 94 5 87 5 49 39 5 60 25 59 68 5 3 5 A B C D E F G H I Suflow rotometer are required to regulate the air flow from the air pump The air injected into the system regulates the backwash frequency These suflow kits are included with the purchase of the filter A B C H I Overall...

Page 41: ...ludge Water Loss Shipping Weight 1 8 HP 1 60 115 15 13 2 6 6 500 750 gpm 50 20000 6 Fipt 2x 6 Fipt 180 apart 1 5 Fip 6 Fipt 6 Fipt 50 150 gallons 20 PSI 3250 Lbs 114 103 94 49 39 5 61 85 77 5 75 A B C D E F G H I Suflow rotometer are required to regulate the air flow from the air pump The air injected into the system regulates the backwash frequency These suflow kits are included with the purchase of...

Page 42: ...utlet Pipe Sludge Drain Valve Inlet Valve 1000 1500 gpm 100 40000 12 2x 10 3 Fip 12 Fipt 20 PSI 6100 Lbs 150 141 134 76 5 56 5 82 5 84 112 5 A B C D E F G H I Suflow rotometer are required to regulate the air flow from the air pump The air injected into the system regulates the backwash frequency These suflow kits are included with the purchase of the filter Overall Diameter Custom Orienta on availabl...

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