Manganese Greensand
Manganese greensand is a
purple-black granular filter medium processed from
glauconitic greensand. Used in a closed pressure-type
filtration system, manganese greensand will remove iron,
manganese, and hydrogen sulfide to required levels.
Removal Capacities for
Manganese Greensand
| Based on total KMn04
demand*: |
10,000 mg/L KMn04/cu. ft. |
| For iron (Fe+2) alone: |
10,000 mg/L Fe/cu.
ft. |
| For manganese (Mn+2)
alone: |
5,000 mg/L Mn/cu.
ft. |
| For hydrogen sulfide
(H2S) alone: |
2,000 mg/L H2S/cu.
ft. |
Note: Removal capacities
must be based on the total combined concentration of iron,
manganese, and hydrogen sulfide if present. (see
example given below)
* The KMn04
demand is
equivalent to the total quantity of KMn04 required to
oxidize soluble iron, manganese, and hydrogen sulfide in the
raw water.
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The KMn04 demand can be
approximated by the following formula:
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KMn04
demand = [1 x mg/L Fe] + [2 x mg/L Mn]
+ [5 x mg/L H2S] |
Example for
determining number of gallons between regenerations:
Raw Water:
-
3.0 mg/L Fe x 1.0 = 3.0 mg/L
KMn04 equiv.
-
0.3
mg/L Mn x 2.0 = 0.6 mg/L KMn04 equiv.
-
0.2
mg/L H2S x 5.0 = 1.0 mg/L KMn04
equiv.
-
Total: 4.6
mg/L KMn04 demand
Capacity:
| 10,000
mg/L KMn04 |
x |
1 |
= |
2175
gallons/ regeneration/ cu. ft. |
| cu.
ft. |
|
4.6
mg/L KMn04 demand |
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| Intermittent
Regeneration Process |
Soluble iron and manganese are removed
by contact oxidation directly on the greensand grains. Hydrogen
sulfide utilizes the oxidizing capacity of manganese greensand with the
resultant precipitates removed by filtration in the greensand bed.
At the end of a service cycle
(determined by the number of gallons treated), the unit is backwashed
and then regenerated down flow (in a manner similar to sodium-cycle
softening) with a solution of potassium permanganate (KMn04).
This will restore the oxidative capacity of manganese greensand.
Depending on raw water conditions, the regeneration level should be 2-4
ounces/cubic foot of greensand (0.13-0.25 lb. KMn04/cubic
foot). It is recommended that regeneration be initiated prior to
complete exhaustion of the greensand to extend the service life of
manganese greensand.
Recommended Operating Procedures for
Intermittently Regenerated Manganese Greensand
| pH |
6.2 - 8.8 |
| Minimum Bed Depth: |
30 Inches |
| Recommended Backwash
Rate: |
Sufficient rate to
expand bed 35 - 40% (12 gpm/sq. ft. at 60¡F) |
| Recommended Backwash
Time: |
10 minutes minimum |
| Service flow rate: |
Continuous Services:
3-5 gpm/sq. ft. of bed area
Intermittent Service: 5-10 gpm/sq.
ft. depending on raw water conditions |
| Regeneration Level: |
2-4 ounces KMn04/cu.
ft. (0.13-0.25 lb./cu. ft.) |
| Regenerant
Concentration: |
0.2-0.5% KMn04 |
| Optimum Regeneration
Time: |
30 - 40 minutes |
For the removal of hydrogen sulfide,
manganese greensand directly oxidizes sulfide and catalyzes the
oxidation reaction. Increased run length and service life of
manganese greensand may be realized by pre-feeding a solution of
chlorine-containing compounds.
Regeneration with KMn04
should be initiated before the unit has reached the point of complete
exhaustion and sulfide is detected in the treated water.
Continuous Regeneration Process
In some installations better
performance may be achieved by oxidizing soluble iron, manganese, and
hydrogen sulfide prior to the manganese greensand filter. This is
accomplished by the continual pre-feed of a solution of KMn04,
chlorine, or a combination of both. The oxidized precipitates are
then filtered out in the greensand bed with subsequent removal during
backwashing. The manganese greensand allows the chemical reactions
to go rapidly to completion and reduces iron and manganese to the
required levels. No additional regeneration is required using this
method. For additional information see our manganese greensand
general bulletin.
Recommended Operating Procedures for
Continuously Regenerated Manganese Greensand
Backwash rate - Sufficient rate to
expand bed 35-40%
Service rate - 3-5 gpm/sq. ft.
Recommended bed depth - 20-24 inches manganese greensand; 15 inches
anthracite
Maximum pressure drop - 10 psi
Physical Characteristics of
Manganese Greensand
Form: Black nodular granules of
manganese-coated natural greensands
| Apparent Density: |
85 lb./cu. ft. |
| Shipping Weight: |
89 lb./cu. ft. |
| Screen Grading: |
18 x 60 mesh |
| Effective Size: |
0.30-0.35 mm. |
| Uniformity
Coefficient: |
Less than 1.60 |
| Specific Gravity: |
Approx. 2.4 |
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GreensandPlus
The Next Step in Greensand Performance
GreensandPlus is a purple-black filter media used for removing soluble iron, manganese, hydrogen sulfide, arsenic and radium from well water supplies.
Like it's sister product manganese greensand, the substrate media has a manganese dioxide coated surface that acts as a catalyst in the oxidation-reduction reaction of iron and manganese. The difference between GreensandPlus and manganese greensand is in the substrate that forms the core of the media and the method by which the manganese dioxide coating is attached to that substrate. Greensand Plus has a silica sand core and the coating is fused to it while Manganese Greensand has a glauconite core and the coating is ionically bound to it.
The silica sand core of GreensandPlus allows it to better withstand operating conditions in waters that are low in silica and TDS and hardness. Thus, if you currently are using manganese greensand and are feeding sodium aluminate, you will likely be able to eliminate the aluminate feed by switching to GreensandPlus. Also, GreensandPlus can withstand higher operating temperatures and higher differential pressures than can manganese greensand. The higher differential pressure may allow for a longer run length, but, if nothing else, allows for more operational margin of error.
Along with the added benefits, comes the fact that GreensandPlus is an exact replacement for manganese greensand. It can be used in CR and IR applications and requires no changes in backwash rate or times or chemical feeds. Greensand has received the WQA Gold Seal Certification for compliance with NSF/ANSI 61. It is available in easy-to-handle 1/2 cubic foot bags or 1 metric ton (2205 lbs) super sacks.
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The approximate clean bed pressure drop for each foot of GreensandPlus bed depth is shown above. Pressure drop increases as the service run progresses.
Following a service cycle, GreensandPlus should be backwashed for up to 10 minutes with a minimum bed expansion of 40%. At a backwash water temperature of 55°F, a 12gpm/sq. backwash rate is required.
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Note: The production of GreensandPlus is not dependent on mining; therefore, it is readily available from stock for shipment.
MSDS
 Greensand MSDS
Greensand Plus MSDS
Typical Sieve Analysis
Greensand
Greensand Plus
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