One Cubic Foot of Clack MTM For Iron, Manganese and Hydrogen Sulfide Reduction
Clack MTM is a granular manganese dioxide filtering media used for reducing iron, manganese and hydrogen sulfide from water. Its active surface coating oxidizes and precipitates soluble iron and manganese. Hydrogen sulfide is oxidized to a sulfur. The precipitates are filtered out in the granular bed and removed by backwashing.MTM consists of a light weight granular core with a coating of manganese dioxide. The coating provides an example of contact filtration where the media itself provides the oxidizing potential. This allows for a much broader range of operation than many other iron removal medias. A pH level as low as 6.2 can be treated. Dissolved oxygen is not essential. The medias light weight reduces backwash water requirements.
When the oxidizing power of MTM is reduced, the bed has to be regenerated with a weak solution of potassium permanganate (KMnO4), thus restoring its oxidizing capacity. A regenerating solution of 1 to 2 ounces (dry weight) of potassium permanganate per cubic foot is sufficient for normal regeneration. Upon start-up a new bed should be backwashed and caution taken to insure that the lightweight media is not backwashed to drain. A new bed should be regenerated the evening of installation. Operating the filter after its oxidizing capacity is exhausted will reduce its service life and may cause staining.
MTM requires either intermittent or continuous regeneration to maintain its oxidizing capacity. A solution of potassium permanganate (or chlorine then potassium permanganate) can be pre-fed to maintain capacity. In the latter case, the manganese dioxide coating acts as a catalyst to enhance the oxidation reaction and as a buffer to reduce any excess potassium permanganate concentration and prevent it from entering the service lines.
Addition of other chemicals to influent or backwash water which contacts MTM media may inhibit iron, manganese or hydrogen sulfide removal or may break down or coat MTM media. Before adding any chemical to the influent or backwash water, other than chlorine or potassium permanganate, the chemicals compatibility with MTM should be thoroughly tested.
Broad operating range for iron reduction
Lower pressure loss through the bed with high flock holding capacity
Effective hydrogen sulfide, iron and manganese reduction.
Light weight requires lower backwash rates and reduces pumping requirements
Chlorine can be beneficial in extending filter run times
Low attrition loss for long bed life
Lower shipping cost
Color: Dark brown
Bulk Density: 45-50 lbs./cu. ft.
Specific Gravity: 2.0 gm/cc
Effective Size: 0.43 mm
Uniformity Coefficient: 2.0
Mesh Size: 12 x 50
CONDITIONS FOR OPERATION
Water pH range: 6.2-8.5
Maximum water temp: 100 F/38 C
Bed depth: 24-36 in.
Freeboard: 50% of bed depth (min.)
Service flow rate: Continuous 2-5 gpm/sq. ft., intermittent flows up to 10 gpm/ft.2
Backwash flow rate: At 60 F 8-10 gpm/sq. ft. for tanks ≤ 12 diameter, 10-12 gpm/sq. ft. for tanks ≥ 13
Backwash expansion rate: 20-40% of bed depth (min.)
MAXIMUM PRACTICAL LIMIT
Iron 15 ppm
Manganese 5 ppm
Hydrogen Sulfide 2 ppm
INFLUENT AND BACKWASH LIMITATIONS
Oil: None present
Polyphosphates: None present
Air Scour not allowed
Use Cl2, KMnO4 or both
KMnO4 Dosage 1.5-2.0 oz (by dry weight)/ft3
Regeneration time greater than 30 minutes
Rinse until all traces of KMnO4 are gone
10,000 gallons of water containing1 mg/L Iron per cu.ft. regeneration
5,000 gallons of water containing1 mg/L Manganese per cu.ft. regeneration
2,000 gallons of water containing1 mg/L Hydrogen Sulfide per cu.ft. regeneration
For dilute solutions mg/L = ppm
37,850 mg KMnO4 demand
KMnO4 demand = [1 x mg/L Fe] +[2 x mg/L Mn] + [5 x mg/L H2S]
Soluble Fe = 3.0 mg/L Fe, Soluble Mn = 0.3 mg/L Mn, H2S = 0.2 mg/L H2S
KMnO4 demand = [1 x 3.0 mg/L Fe] +[2 x 0.3 mg/L Mn] + [5 x 0.2 mg/L H2S]
KMnO4 demand = [3.0 mg/L] + [0.6 mg/L] + [1.0 mg/L]
KMnO4 demand = 4.6 mg/L
(37,850 mg KMnO4 demand per cu. ft. regen./4.6 mg per Liter KMnO4 demand) X (1 gallon/3.785 Liters) = 2,174 gallons per cu. ft. regenerated