is an efficient and economical media for the reduction
of dissolved iron and manganese compounds from raw water
supplies. It may be used in either gravity fed or pressurized
water treatment systems. Birm acts as an insoluble catalyst
to enhance the reaction between dissolved oxygen (D.O.)
and the iron com pounds. In ground waters the dissolved
iron is usually in the ferrous bicarbonate state due to
the excess of free carbon dioxide and is not filterable.
Birm, acting as a catalyst between the oxygen and the
soluble iron compounds, enhances the oxidation reaction
of Fe++ to Fe+++ and produces ferric hydroxide which precipitates
and may be easily filtered. The physical characteristics
of Birm provide an excellent fi lter media which is easily
cleaned by backwashing to remove the precipitant. Birm
is not consumed in the iron removal operation and therefore
offers a tremendous economic advantage over many other
iron removal methods.
advantages of Birm include; long material life with relatively
low attrition loss, a wide temperature performance range
and extremely high removal efficiency. Negligible labor
costs are involved because Birm does not require chemicals
for regeneration, only periodic backwashing is required.
using Birm for iron removal, it is necessary that the
water: contain no oil or hydrogen sulfide, organic matter
not to exceed 4-5 ppm, the D.O. content equal at least
15% of the iron content with a pH of 6.8 or more. If the
influent water has a pH of less that 6.8, neutralizing
additives such as Clack Corosex®,
Calcite or soda ash may be used
prior to the Birm filter to raise the pH. A water having
a low D.O. level may be pre treat ed by aeration.
of chemicals to influent or backwash water which contacts
Birm media may inhibit iron or manganese removal or may
break down or coat Birm media. Chlorination greatly reduces
Birm’s activity. High concentrations of chlorine
compounds may deplete the catalytic coating. Polyphosphates
are known to coat Birm and reduce Birm’s ability
to remove iron or manganese. Before adding any chemical
to the influent or backwash water, the chemical's compatibility
with Birm should be thoroughly tested.
Birm may also be used for manganese reduction with the
same dependability as iron removal. In these applications
the water to be treated should have a pH of 8.0-9.0 for
best results. If the water also contains iron, the pH
should be below 8.5. High pH conditions may cause the
formulation of colloidal iron which is very difficult
to filter out. All other conditions remain the same for
either manganese or iron removal.
Under the proper conditions, no chemicals to purchase
maintenance. Regeneration not required.
Iron removal efficiency is extremely high.
Negligible labor cost: only periodic backwashing required.
Durable material with a long life and wide temperature
Weighs only 40-45 lbs./cu. ft.
Bulk Density: 40-45 lbs./ cu. ft.
Mesh Size: 10 x 40
Specific Gravity: 2.0 gm/cc
Effective Size: 0.48 mm
Uniformity Coefficient: 2.7
should be greater than two times the combined sulfate
Maximum water temp: 100oF/38oC
Water pH range: 6.8-9.0
Dissolved Oxygen (D.O.) content must be equal to at
least 15% of the iron (or iron and manganese) content.
Bed depth: 30-36 in.
Freeboard: 50% of bed depth (min.)
Backwash rate: 10-12 gpm/sq. ft.
Backwash Bed Expansion: 20-40% of bed depth (min.)
Service flow rate: 3.5-5 gpm/sq. ft. intermittent
flow rates and/or favorable local conditions may allow
higher flow rates
AND BACKWASH LIMITATIONS
chlorine concentration less than 0.5 ppm
Hydrogen Sulfi de should be removed prior to contact
with Birm media
Oil: None Present
Polyphosphates: None present
is a registerd Tradmark of Clack Corp.