Removal of Organic Matters and Nutrients by Using Bio-balls …
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25 mg/l, efficiency increases from 89.2 to 94.48%, and for corn cobs, with increase
in concentration from 15 to 35 mg/l, efficiency increases from 76.37 to 94.63%.
For bio-balls with initial concentration of 25 mg/l and corn cobs with initial
concentration of 20 mg/l (optimum condition), the efficiency increases with increase
in operation time from 6 to 24 h. The nitrate concentration in the effluent was relatively
stable during the surface loading stage, but there were fluctuations during the sludge
concentration and temperature stages which takes place around operation time of
6 h. Best removal efficiency was achieved in 24 h for all the five batches for both the
media. So for optimum removal, the reactor must have a hydraulic retention time of
minimum one day.
The nitrogen removal in this process most commonly as well as economically
accomplished in two stages: nitrification and denitrification [7]. Nitrification converts
ammonia to oxidized nitrogen, i.e., nitrite and nitrate, and then, it is converted to a
nitrogen gas in the next denitrification process. The step produces nitric oxide (NO),
nitrous oxide (N 2 O), and nitrogen gas (N 2 ). All the products are gaseous in nature
which can be released in atmosphere. Generally, nitrosomonas and nitrobacter are
responsible for the nitrification in the wastewater. For denitrification, denitrifying
organisms and an organic carbon source are responsible for decomposition. The nitrification rate is determined by the load of organic matter, ammonium concentration,
and oxygen concentrations. Nitrification rate depends on mixture and heterotrophs
distribution. The rate limiting substrate for nitrification may be ammonia or oxygen.
According to a study, for nitrification, DO level in aerated reactor is sufficiently
high which penetrates through outer layer of the oxygen-consuming hetrotroph and
in nitrifying bacteria. The nitrification dependS upon oxygen concentration. For
MBBR, the liquid film diffusion was an essential parameter.
3.2 Comparison of Removal Efficiency of Phosphate
for Different Batches
Figure 5a, b shows the variation of removal efficiencies for bio-balls and corn cobs
as media for different concentration of phosphate and different operating time. For
both the media, efficiency increases with increase in concentration and increase in
operating time. For bio-balls, with increase in concentration from 5 to 25 mg/l,
efficiency increases from 60.1 to 96.9%, and for corn cobs, efficiency increases from
73.2 to 93.7%.
For bio-balls with initial concentration of 20 mg/l and corn cobs with initial
concentration of 10 mg/l (optimum condition), the efficiency increases with increase
in operation time from 6 to 24 h. Best removal efficiency was achieved in 24 h for
all the five batches for both the media.
Phosphorus is removed biologically in this process by moving bed bio-film
process [8]. The biological phosphorus removal is done by phosphate-accumulating
organisms (PAO) because they have the ability for accumulating phosphate which
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25 mg/l, efficiency increases from 89.2 to 94.48%, and for corn cobs, with increase
in concentration from 15 to 35 mg/l, efficiency increases from 76.37 to 94.63%.
For bio-balls with initial concentration of 25 mg/l and corn cobs with initial
concentration of 20 mg/l (optimum condition), the efficiency increases with increase
in operation time from 6 to 24 h. The nitrate concentration in the effluent was relatively
stable during the surface loading stage, but there were fluctuations during the sludge
concentration and temperature stages which takes place around operation time of
6 h. Best removal efficiency was achieved in 24 h for all the five batches for both the
media. So for optimum removal, the reactor must have a hydraulic retention time of
minimum one day.
The nitrogen removal in this process most commonly as well as economically
accomplished in two stages: nitrification and denitrification [7]. Nitrification converts
ammonia to oxidized nitrogen, i.e., nitrite and nitrate, and then, it is converted to a
nitrogen gas in the next denitrification process. The step produces nitric oxide (NO),
nitrous oxide (N 2 O), and nitrogen gas (N 2 ). All the products are gaseous in nature
which can be released in atmosphere. Generally, nitrosomonas and nitrobacter are
responsible for the nitrification in the wastewater. For denitrification, denitrifying
organisms and an organic carbon source are responsible for decomposition. The nitrification rate is determined by the load of organic matter, ammonium concentration,
and oxygen concentrations. Nitrification rate depends on mixture and heterotrophs
distribution. The rate limiting substrate for nitrification may be ammonia or oxygen.
According to a study, for nitrification, DO level in aerated reactor is sufficiently
high which penetrates through outer layer of the oxygen-consuming hetrotroph and
in nitrifying bacteria. The nitrification dependS upon oxygen concentration. For
MBBR, the liquid film diffusion was an essential parameter.
3.2 Comparison of Removal Efficiency of Phosphate
for Different Batches
Figure 5a, b shows the variation of removal efficiencies for bio-balls and corn cobs
as media for different concentration of phosphate and different operating time. For
both the media, efficiency increases with increase in concentration and increase in
operating time. For bio-balls, with increase in concentration from 5 to 25 mg/l,
efficiency increases from 60.1 to 96.9%, and for corn cobs, efficiency increases from
73.2 to 93.7%.
For bio-balls with initial concentration of 20 mg/l and corn cobs with initial
concentration of 10 mg/l (optimum condition), the efficiency increases with increase
in operation time from 6 to 24 h. Best removal efficiency was achieved in 24 h for
all the five batches for both the media.
Phosphorus is removed biologically in this process by moving bed bio-film
process [8]. The biological phosphorus removal is done by phosphate-accumulating
organisms (PAO) because they have the ability for accumulating phosphate which