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The
Biofilter Media incorporates the highly reliable trickling
filter process. Operation cost can be brought down among
all mechanical systems. It is also one of the most compact
system requiring minimum area space. Suitable for all
types of development scheme. The major features of the
biofilter media system are :
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Highly
efficient in Biochemical Oxygen Demand (B.O.D) removal.
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One of
the most compact treatment plants, requires about 0.06 –
0.09 m2/p.e.
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Low initial
capital outlay.
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Low operation
and maintenance costs
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No skilful
operator required.
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No special
mechanical equipment.
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Non-clog and
uniform self-distribution biofilter media.
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Easily
expandable.
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Aesthetical
outlook.
How is the waste
water treated?
Nutrient and oxygen are transferred to the biomass layer
and waste products are transferred to the moving water,
primarily b y
diffusion. As the microorganisms on the filter surface
metabolize the waste and reproduce,
they will gradually cause an
increase in the depth of the slime layer. With thickening
of the biological layer, the microorganisms in the
interior layers find themselves in a nutrient-limited
situation, since the organic matter
and oxygen are utilized near the surface.
Eventually these
interior cells die and lyse, breaking the contact between
the slime layer and the support medium. When sufficient
cells have lysed, the slime layer will slough off and be
carried from the filter by the waste flow.
The solids in the filter effluent are removed from the
flow in a secondary clarifier.
B.O.D Reduction
In biological treatment of wastewater, many parameters,
such as biochemical oxygen demand (B.O.D.)
concentration, origin of the wastewater, temperature, pH,
and nutrient balance, interact in such a way that each
plant must be designed individually. Based on empirical
data collected during years of experience, PESB assists
clients to design Biofilters with optimum performance and
economy. PESB’s Biofilters are designed for a wide variety
of applications, covering the full field from high-rate
Biofilters for partial treatment of industrial wastewater
to full secondary treatment of domestic sewage.
Hydraulic Load
To utilize fully the available surface area of the
Biofilter, a minimum amount of water must be fed to the
Biofilter, i.e. minimum hydraulic load of wastewater per
square meter of top layer surface per hour (m3/m2.h).
This water also helps to flush out the biological sludge.
From experience, the minimum hydraulic load should be 2.0
m3/m2.h for a static distribution
system and 1.5 m3/m2.h for a
rotating distributor.
Normally no
recirculation is necessary due to the high efficiency of
the Biofilters, but for some very high concentrated
wastewater, recirculation is necessary to reach the
minimum hydraulic load without exceeding the organic load
for which the Biofilter is designed.
The use of rotating
distributors together with shallow Bioiflter installations
also allows for lower hydraulic loading rates. This
situation is common for secondary Biofilters treating
domestic sewage due to low B.O.D. concentration of those
wastes
Re-Circulation Ratio
Recirculation ratio is
depended on the organic load and the top surface hydraulic
load to maintain the microorganisms at the aerobic state.
|
Hydraulic load |
= |
( QTotal
/ A) |
|
Recirculation ratio |
= |
( QTotal
/
QDWF) |
| A = Surface area |
A = Surface area |
QDWF
= Dry whether flow |
Re-Circulation Sketch
Operation Condition
A Biofilter forms an
ecological biological system, in balance under certain
conditions. The incoming flow must not contain toxic
substances and should fulfill the following
recommendations for an optimum performance.
PH = 6.5 – 8.0
B.O.D. : NH4-N : PO4-P ratio = 100 : 5 : 1
Temperature = Maximum 35 OC
Particle size = Maximum 10 mm
Biofilter Equipments
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Biofilter distributor |
Easy to
service Biofilter distributor |
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|
Biofilter Pump |
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