SAND FILTRATION
DMP normally employs the following styles of sand filtration for polishing the effluent from the clarifier. The above is a picture of a 2 vessel sand filter.
· 1 Vessel Pressure Sand Filter
· 2 Vessel Pressure Sand Filter
· 3 Vessel Pressure Sand Filter
· 4 Vessel Pressure Sand Filter
· 5 Vessel Pressure Sand Filter
· DynaSand Continuous Sand Filter
Single-station pressure Sand Filter Module
Pressure sand filter is a operated as polishing filter for the final clarified effluent. The sand filter plumbing rack is designed to enable the sand filter to be backwashed automatically every four to eight hours of operation as a precautionary measure to avoid plugging of the sand filters.
The sand filter module is also designed for manual operation should upset conditions clog the sand filter prematurely and the filter will require backwashing sooner.
Equipment Supplied:
· single-station Sand Filter
· Plumbing Manifold
· Level Controlled Sand Filter Feed Tank
· Sand Filter Feed Pump
· Backwash Water Feed Control
· Pressure Alarm Switch
· Tap Water Supply Backwash Feature
Operation Sequence
The operation of the sand filter is controlled through the operator interface. The sand filter is put into operation by placing the main control panel switches in the auto mode.
Automatic Mode Operation
Clarified water is collected in the level controlled sand filter feed tank. when start pump ball level is reached, a single pump will start and supply solution to the sand filter module. The level of the solution will drop and activate the stop pump ball level. As the solution rises it will again activate the start pump ball level. This will start the alternate pump. If either pump cannot keep up with the incoming flow or the pump should fail the solution will continue to rise and activate start second pump level control and cause other pump to come on line to assist the other pump. If the solution still continues to rise a high level control alarm will sound alerting operator of impending flood conditions and divert the treatment system pumps to emergency holding until the situation can be corrected.
Unless the sand filters require backwashing sooner they will automatically be backwashed when the preset time is accumulated. The program timer is set at eight (8) hours, but can be changed based on experience.
Place main sand filter in auto position for normal operation.
Manual Mode
All sand filters must be placed in the manual run position in order to manually backwash the filters. This is accomplished by placing the main sand filter control in the manual position and placing the individual sand filter switches in run position.
Individual sand filters may now be selected for manual backwash. This is accomplished by placing the switch of the unit selected in backwash position. The unit will now start to backwash and the time of backwash is to be determined by the operator. Do not back wash more than one unit at a time.
· When backwash is complete the unit can be put back on line by placing the individual control back in run position.
· The next unit may now be taken out of service and backwashed.
· To place all units back in automatic run mode, set main control to all auto.
· Place control for sand filter in manual position. If sand filters is to be manually backwashed, it must be in the manual mode.
Pressure Alarm
High pressure alarm will sound when preset pressure differential over clean sand operation is reached. The alarm condition can be acknowledged through the alarm menu. This high pressure alarm is a warning that sand filters are approaching the need for back washing.
Pressure sand filters are operated as polishing filters for the final clarified effluent. The sand filter plumbing rack is designed to enable one sand filter to be backwashed while the other units are in the service cycle.
The sand filters are programmed to be backwashed automatically according to the pre-set time entered into the operator interface. One(1) to Four(4) hours of operation with three(3) to ten(10) minutes of backwash, is typically used as a precautionary measure to avoid plugging of the sand filters.
The sand filter module is also designed for manual operation should upset conditions clog sand filters prematurely and they require backwashing sooner.
Equipment Supplied:
· multi-station Sand Filters
· Plumbing Manifold
· Level Controlled Sand Filter Feed Tank
· Sand Filter Feed Pump(s)
· Backwash Tap Water Feed Control
· Pressure Transmitter
· Pressure Relief Bypass
· Tap Water Supply Backwash
Feed Pump Operation
Clarified water is collected in the level controlled sand filter feed tank.
Single feed pump with three level controls:
When the start pump ball level is activated, a pump will start and supply water to the sand filter module. As the water level drops, the stop pump ball level will deactivate, and stop the pump. As the water rises it will again activate the start pump ball level. This will start the pump. If the water still continues to rise to the high level ball level control, an alarm will sound alerting operator of impending flood conditions.
Dual ratcheting feed pumps with four level controls:
When the start first pump ball level is activated, pump A will start, and supply water to the sand filter module. As the water level drops, the stop pump ball level will deactivate, and stop pump A. As the water rises, it will again activate the start first pump ball level. This will start pump B. If the water continues to rise, the start second pump level control will activate, starting pump A, along with pump B. When the water level drops below the start first pump level control, pump A will shut off, leaving pump B on alone. If the water level does not drop, but still continues to rise to the high level ball level control, an alarm will sound alerting operator of impending flood conditions.
Sand Filter Operation
Sequence:
The sand filters are placed in operation by using the operator interface switches in the AUTO - OFF - MANUAL mode required for the desired operation. There is a Backwash Override switch on the sand filter screen of the operator interface. This is for forcing the filters into automatic backwash at anytime during the filtering cycle.
Automatic Mode Operation
From the sand filter control screen of the operator interface, place the sand filters into the AUTO position. The sand filters will follow the automatic sequence of filtering for the pre-set time entered, followed by a backwash cycle for the pre-set time entered.
· When sand filter #1 is in service, filter #2 is in stand-by.
· When sand filter #1 is backwashing, filter #2 will be in filtering service.
· When #1 filter goes back into filtering service, #2 will return to stand-by mode.
An example using 2 filters:
Filter Service Backwash Stand-By
Start filtering #1 -- #2
After filter cycle time-out #2 #1 --
After backwash time-out #1 #2 --
Filter cycle #1 -- #2
Manual Mode Operation
The MANUAL position should be used during the following conditions:
· A means of immediately backwashing the filters due to an upset from the clarifier.
· Avoiding an automatic backwash if the backwash return sump is in a possible high level condition.
· Bypassing a specific filter due to breakage or maintenance.
· Bypassing a specific filter due to acid cleaning.
Manual operation will open all the air operated automatic valves, leaving it up to the operator to select the service valves for backwashing. The individual sand filters may now be selected for manually backwashing or manually running. The pre-set times for the automatic filter cycle do not apply to all manual functions.
Note: Do not back wash more than one unit at a time. The next unit may now be taken out of service and backwashed. If filter #1 is backwashing, filters #2, #3, #4, etc., must have the manual valves open for filtering. See the attached schematic for specific valve operations.
To start the manual backwash process:
· Close all manual service valves.
· Shut off all system feed pumps.
· From the sand filter control screen of the operator interface, using the proper F(key), place sand filters into the MANUAL position.
· Select the sand filter to backwash.
· Open the appropriate manual service valves according to the schematic.
· Backwash for 3-10 minutes, or as long as is necessary. If the discharge is visible, you will be able to see a change of clarity as the filter backwashes away the sludge. The sand filter feed pump provides the backwash water. All the water for backwashing is processed through the other filter.
· Close the valves for the filter that was backwashed. Select the next filter and open the manual service valves for it.
· Go back to step 6. Continue until all filters are backwashed.
· Return all manual service valves to their original position.
· From the sand filter control screen of the operator interface, using the proper F(key), place sand filters into the AUTO position.
Pressure Alarm
High pressure alarm will sound when preset pressure differential over clean sand operation is reached. This high pressure alarm is a warning that sand filters are in need of back washing. Automatic backwashing will begin immediately.
Pressure Alarm Activated Backwash Steps:
· When the pressure transmitter activates, the alarm will sound, and shut down incoming flow to the system. The operator should acknowledge the alarm at this point.
· The sand filter feed pump will purge the water from the sand filter feed tank. All automatic valves to the sand filter inlets will close, forcing the water to go to the reject return tank or sump.
· The sand filter feed pump will shut off at the stop pump level, then the tap water valve will open filling the sand filter feed tank to the start pump level.
· The feed pump starts, and backwashes filter #1 from filter #2, using the pre-set times entered into the operator interface. The tap water valve will continue to stay open as long as level of water in the tank is below the high level .
· When backwashing is complete, the automatic cycle will start again.
· All system feed pumps will start again to begin processing waste.
Note: If manual cleaning is needed, refer to the sand filter cleaning operations portion of this manual.
The high pressure setting should be set no more than ten(10) psi higher than a clean sand pumping condition.
Pressure Relief By-pass
The pressure relief by-pass will provide a small stream approximately 1/4" to 3/8" wide. This is to relieve any sudden pressure increase, i.e., pump start-up, sludge build-up, etc.
Pressure Sand Filter Sand Cleaning
Proper operation of the system, and preventative maintenance will avoid any upsets to the filter system. Occasionally it may become necessary to clean the sand in the pressure sand filter vessel due to contamination of either a sludge buildup, or Calcium Sulfate build-up.
To clean the pressure filter, do the following:
· Turn the Chemical Feed Pumps OFF.
· Turn the Sand Filter Feed Pump OFF.
· Turn the all sand filters mode to OFF.
· Close the manual service ball valves on the filter plumbing rack.
· Turn the pressure bleed valve, on the top of the filter, counter-clockwise to open.
· Turn the filter cap counter-clockwise, using the hexagonal wrench provided, until the top is removed.
· Reach inside and move the disperser aside carefully.
· Remove any sludge build-up on top of the sand. A wet / dry vacuum is useful for this.
· Fill the filter with tap water to just above the sand level.
· Add two(2) or three(3) gallons of full strength muriatic acid and allow the acid to dissolve the sludge. Let sit for as long as possible.
Note: It may be necessary to gently agitate the sand bed via air lancing or mixing with a piece of PVC pipe or a wood handle. Be careful not to splash the acid out the top!
· With a gloved hand, return the disperser to its original position.
· Return the cap to the top of the vessel and tighten with the hexagonal wrench.
· Close the bleed valve securely.
· Open all the manual service ball valves on the filter plumbing rack.
· Place the all sand filters mode to MANUAL. Select the proper filter, and place in Manual Backwash.
· Backwash for 5 - 8 minutes.
· Return the all sand filters mode to AUTO.
· Return the all pumps to AUTO.
Sand Filter Operation
Sequence
The sand filters are placed in operation by using the operator interface switches in the AUTO - OFF - MANUAL mode required for the desired operation. There is a Backwash Override switch on the sand filter screen of the operator interface. This is for forcing the filters into automatic backwash at anytime during the filtering cycle.
Automatic Mode Operation
From the sand filter control screen of the operator interface, place the sand filters into the AUTO position. The sand filters will follow the automatic sequence of filtering for the pre-set time entered, followed by a backwash cycle for the pre-set time entered.
· When sand filters #1 and #2 are in service, filter #3 is in stand-by.
· When sand filter #1 is backwashing, filters #2 and #3 will be in filtering service.
· After filter #1 finishes backwash, it will return to filter service along with #3. Filter #2 will backwash.
· After filter #2 finishes backwash, it will return to filter service along with #1. Filter #3 will backwash.
· After filter #3 finishes backwash, it will return to stand-by. Filters #1 and #2 will return to filter service.
An example using 3 filters:
Filter Service Backwash Stand-By
Start filtering #1, #2 -- #3
After filter cycle time-out #2, #3 #1 --
After backwash time-out #1, #3 #2 --
After backwash time-out #1, #2 #3 --
Filter cycle #1, #2 -- #3
Manual Mode Operation
The MANUAL position should be used during the following conditions:
· A means of immediately backwashing the filters due to an upset from the clarifier.
· Avoiding an automatic backwash, if the backwash return sump is in a possible high level condition.
· Bypassing a specific filter due to breakage or maintenance.
· Bypassing a specific filter due to acid cleaning.
Manual operation will open all of the air operated automatic valves, leaving it up to the operator to select the service valves for backwashing. The individual sand filters may now be selected for manually backwashing or manually running. The pre-set times for the automatic filter cycle do not apply to all manual functions.
Note: Do not back wash more than one unit at a time. The next unit may now be taken out of service and backwashed. If filter #1 is backwashing, filters #2, #3, #4, etc., must have the manual valves open for filtering. See the attached schematic for specific valve operations.
To start the manual backwash process:
· Close all manual service valves.
· Shut off all system feed pumps.
· From the sand filter control screen of the operator interface, using the proper F(key), place sand filters into the MANUAL position.
· Select the sand filter to backwash.
· Open the appropriate manual service valves according to the schematic.
· Backwash for 3-10 minutes, or as long as is necessary. If the discharge is visible, you will be able to see a change of clarity as the filter backwashes away the sludge. The sand filter feed pump provides the backwash water. All the water for backwashing is processed through the other filter.
· Close the valves for the filter that was backwashed. Select the next filter and open the manual service valves for it.
· Go back to the backwash step. Continue until all filters are backwashed.
· Return all manual service valves to their original position.
· From the sand filter control screen of the operator interface, using the proper F(key), place sand filters into the AUTO position.
Pressure Alarm Activated Backwash Steps
When the pressure transmitter activates, the alarm will sound, and shut down incoming flow to the system. The operator should acknowledge the alarm at this point.
· The sand filter feed pump will purge the water from the sand filter feed tank. All automatic valves to the sand filter inlets will close, forcing the water to go to the reject return tank or sump.
· The sand filter feed pump will shut off at the stop pump level, then the tap water valve will open filling the sand filter feed tank to the start pump level.
· The feed pump starts, and backwashes filter #1 from filter #2 and #3, using the pre-set times entered into the operator interface. The tap water valve will continue to stay open as long as level of water in the tank is below the high level .
· When #1 has completed backwashing, #2 will backwash from filter #1 and #3.
· When #2 has completed backwashing, #3 will backwash from filter #1 and #2.
· When backwashing #3 is complete, the automatic cycle will start again.
· All system feed pumps will start again to begin processing waste.
Sand Filter Operation
Sequence:
The sand filters are placed in operation by using the operator interface switches in the AUTO - OFF - MANUAL mode required for the desired operation.
There is a Backwash Override switch on the sand filter screen of the operator interface. This is for forcing the filters into automatic backwash at anytime during the filtering cycle.
Automatic Mode Operation
From the sand filter control screen of the operator interface, place the sand filters into the AUTO position. The sand filters will follow the automatic sequence of filtering for the pre-set time entered, followed by a backwash cycle for the pre-set time entered.
· When sand filters #1, #2 and #3 are in service, filter #4 is in stand-by.
· When sand filter #1 is backwashing, filters #2, #3 and #4 will be in filtering service.
· After filter #1 finishes backwash, it will return to filter service along with #3 and #4. Filter #2 will backwash.
· After filter #2 finishes backwash, it will return to filter service along with #1 and #4. Filter #3 will backwash.
· After filter #3 finishes backwash, it will return to filter service along with #1 and #2. Filter #4 will backwash.
· After filter #4 finishes backwash, it will return to stand-by. Filters #1, #2 and #3 will return to filter service.
An example using 4 filters:
Filter Service Backwash Stand-By
Start filtering #1, #2, #3 -- #4
After filter cycle time-out #2, #3, #4 #1 --
After backwash time-out #1, #3, #4 #2 --
After backwash time-out #1, #2, #4 #3 --
After backwash time-out #1, #2, #3 #4 --
Filter cycle #1, #2, #3 -- #4
Manual Mode Operation
The MANUAL position should be used during the following conditions:
· A means of immediately backwashing the filters due to an upset from the clarifier.
· Avoiding an automatic backwash, if the backwash return sump is in a possible high level condition.
· Bypassing a specific filter due to breakage or maintenance.
· Bypassing a specific filter due to acid cleaning.
Manual operation will open all of the air operated automatic valves, leaving it up to the operator to select the service valves for backwashing. The individual sand filters may now be selected for manually backwashing or manually running. The pre-set times for the automatic filter cycle do not apply to all manual functions.
Note: Do not back wash more than one unit at a time. The next unit may now be taken out of service and backwashed. If filter #1 is backwashing, filters #2, #3, #4, etc., must have the manual valves open for filtering. See the attached schematic for specific valve operations.
To start the manual backwash process:
· Close all manual service valves.
· Shut off all system feed pumps.
· From the sand filter control screen of the operator interface, using the proper F(key), place sand filters into the MANUAL position.
· Select the sand filter to backwash.
· Open the appropriate manual service valves according to the schematic.
· Backwash for 3-10 minutes, or as long as is necessary. If the discharge is visible, you will be able to see a change of clarity as the filter backwashes away the sludge. The sand filter feed pump provides the backwash water. All the water for backwashing is processed through the other filter.
· Close the valves for the filter that was backwashed. Select the next filter and open the manual service valves for it.
· Go back to the backwash step. Continue until all filters are backwashed.
· Return all manual service valves to their original position.
· From the sand filter control screen of the operator interface, using the proper F(key), place sand filters into the AUTO position.
Pressure Alarm
High pressure alarm will sound when preset pressure differential over clean sand operation is reached. This high pressure alarm is a warning that sand filters are in need of back washing. Automatic backwashing will begin immediately.
Pressure Alarm Activated Backwash Steps:
· When the pressure transmitter activates, the alarm will sound, and shut down incoming flow to the system. The operator should acknowledge the alarm at this point.
· The sand filter feed pump will purge the water from the sand filter feed tank. All automatic valves to the sand filter inlets will close, forcing the water to go to the reject return tank or sump.
· The sand filter feed pump will shut off at the stop pump level, then the tap water valve will open filling the sand filter feed tank to the start pump level.
· The feed pump starts, and backwashes filter #1 from filter #2, #3, and #4, using the pre-set times entered into the operator interface. The tap water valve will continue to stay open as long as level of water in the tank is below the high level .
· When #1 has completed backwashing, #2 will backwash from filter #1, #3 and #4.
· When #2 has completed backwashing, #3 will backwash from filter #1, #2 and #4.
· When #3 has completed backwashing, #4 will backwash from filter #1, #2 and #3.
· When backwashing #4 is complete, the automatic cycle will start again.
· All system feed pumps will start again to begin processing waste.
Sand Filter Operation
Sequence:
The sand filters are placed in operation by using the operator interface switches in the AUTO - OFF - MANUAL mode required for the desired operation. There is a Backwash Override switch on the sand filter screen of the operator interface. This is for forcing the filters into automatic backwash at anytime during the filtering cycle.
Automatic Mode Operation
From the sand filter control screen of the operator interface, place the sand filters into the AUTO position. The sand filters will follow the automatic sequence of filtering for the pre-set time entered, followed by a backwash cycle for the pre-set time entered.
· When sand filters #1, #2, #3 and #4 are in service, filter #5 is in stand-by.
· When sand filter #1 is backwashing, filters #2, #3, #4 and #5 will be in filtering service.
· After filter #1 finishes backwash, it will return to filter service along with #3, #4 and #5. Filter #2 will backwash.
· After filter #2 finishes backwash, it will return to filter service along with #1, #4 and #5. Filter #3 will backwash.
· After filter #3 finishes backwash, it will return to filter service along with #1, #2 and #5. Filter #4 will backwash.
· After filter #4 finishes backwash, it will return to filter service along with #1, #2 and #3. Filter # 5 will backwash.
· After filter #5 finishes backwash, it will return to stand-by. Filters #1, #2, #3 and #4 will return to filter service.
An example using 5 filters:
Filter Service Backwash Stand-By
Start filtering #1, #2, #3, #4 -- #5
After filter cycle time-out #2, #3, #4, #5 #1 --
After backwash time-out #1, #3, #4, #5 #2 --
After backwash time-out #1, #2, #4, #5 #3 --
After backwash time-out #1, #2, #3, #5 #4 --
After backwash time-out #1, #2, #3, #4 #5 --
Filter cycle #1, #2, #3, #4 -- #5
Manual Mode Operation
The MANUAL position should be used during the following conditions:
· A means of immediately backwashing the filters due to an upset from the clarifier.
· Avoiding an automatic backwash, if the backwash return sump is in a possible high level condition.
· Bypassing a specific filter due to breakage or maintenance.
· Bypassing a specific filter due to acid cleaning.
Manual operation will open all of the air operated automatic valves, leaving it up to the operator to select the service valves for backwashing. The individual sand filters may now be selected for manually backwashing or manually running. The pre-set times for the automatic filter cycle do not apply to all manual functions.
Note: Do not back wash more than one unit at a time. The next unit may now be taken out of service and backwashed. If filter #1 is backwashing, filters #2, #3, #4, etc., must have the manual valves open for filtering. See the attached schematic for specific valve operations.
To start the manual backwash process:
· Close all manual service valves.
· Shut off all system feed pumps.
· From the sand filter control screen of the operator interface, using the proper F(key), place sand filters into the MANUAL position.
· Select the sand filter to backwash.
· Open the appropriate manual service valves according to the schematic.
· Backwash for 3-10 minutes, or as long as is necessary. If the discharge is visible, you will be able to see a change of clarity as the filter backwashes away the sludge. The sand filter feed pump provides the backwash water. All the water for backwashing is processed through the other filter.
· Close the valves for the filter that was backwashed. Select the next filter and open the manual service valves for it.
· Go back to the backwash step. Continue until all filters are backwashed.
· Return all manual service valves to their original position.
· From the sand filter control screen of the operator interface, using the proper F(key), place sand filters into the AUTO position.
Pressure Alarm
High pressure alarm will sound when preset pressure differential over clean sand operation is reached. This high pressure alarm is a warning that sand filters are in need of back washing. Automatic backwashing will begin immediately.
Pressure Alarm Activated Backwash Steps:
· When the pressure transmitter activates, the alarm will sound, and shut down incoming flow to the system. The operator should acknowledge the alarm at this point.
· The sand filter feed pump will purge the water from the sand filter feed tank. All automatic valves to the sand filter inlets will close, forcing the water to go to the reject return tank or sump.
· The sand filter feed pump will shut off at the stop pump level, then the tap water valve will open filling the sand filter feed tank to the start pump level.
· The feed pump starts, and backwashes filter #1 from filter #2, #3, #4, and #5, using the pre-set times entered into the operator interface. The tap water valve will continue to stay open as long as level of water in the tank is below the high level .
· When #1 has completed backwashing, #2 will backwash from filter #1, #3, #4, and #5.
· When #2 has completed backwashing, #3 will backwash from filter #1, #2, #4, and #5.
· When #3 has completed backwashing, #4 will backwash from filter #1, #2, #3, and #5.
· When #4 has completed backwashing, #5 will backwash from filter #1, #2, #3, and #4.
· When backwashing #5 is complete, the automatic cycle will start again.
· All system feed pumps will start again to begin processing waste.