Experimentation and Evaluation of Biodegradative Kinetic …
167
where, K i is the inhibition coefficient (mg/l). The biokinetic parameters in this model
were estimated by the Lineweaver–Burk plot (1/μ vs. 1/S) (Najafpour 2007). Also,
the most important factor in biodegradation process was determined by Friedman
test by use of the statistical package SPSS.
2.5 Lab Scale Study for Removal of Nitrate in Drinking Water
The lab scale setup consists of reservoir, reactor tank, settling tank, filtration tank and
collection tank (Fig. 1). The reactor and settling tanks were fitted with stirrer. The
filtration tank was made of rectangular glass vessel with dimension of 55 cm in height,
60 cm in length and 35 cm in width. To this, large pebbles (2.0 to 2.5 cm) were packed
in bottom of the vessel followed by small pebbles (0.7–1.5 cm), gravel (0.4–0.6 cm),
coarse sand (0.05–0.1 cm), fine sand (0.15–0.3 mm) and activated carbon (0.75–
1.0 μm). The filtration tank was washed thoroughly with sterile distilled water to
remove the adhering particles in the filter bed. The bottom of the vessel was connected
with an outlet to a collection tank.
About 10 L of fresh drinking water with 100 mg/L of NO 3
− was added to the
reactor tank. Further, 1% of soluble starch and 10 mL of KW1 and YW4 (1:1 v/v)
containing 10
4 CFU/mL were added and allowed to react for 48 h at an optimum
temperature of 30 °C and pH 7. The speed of stirrer in both reactor and settling tank
was adjusted to 120 rpm. After bacterial treatment, the water sample was transferred
to settling tank and mixed thoroughly with commercial grade alum [(Al 2 (SO 4 ) 3 ] and
lime [CaCO 3 ], at normal dosage (alum—25 mg/L and lime—6 mg/L) prescribed by
Central Pollution Control Board, India, for 15 min at 120 rpm and 10 min at 15 rpm
and allowed to settle for 30 min (Ayyasamy et al. 2007). Further, the bacterial biomass
and coagulant particles were removed through the outlet of settling tank followed by
filtration. The bacterial growth, amount of NO 3
− , NO 2
− and NH 4
+ were estimated
in the treated water sample for every 6 h (APHA 2005).
2.6 Pilot Scale Study for Removal of Nitrate in Drinking
Water
The pilot scale plant consists of reservoir (1000 L), inoculum tank (10 L), reactor tank
(1200 L), settling tank (1200 L), sand filter (1200 L) (mode of packing was similar as
mentioned in Sect. 2.4) and collection tank (1200 L). Each tank was interconnected
with pipelines as shown in the Fig. 2. The reactor tank was fitted with peddler to
mix bacterial inoculum with water. The settling tank was also fitted with peddler for
mixing of coagulating agents. The treatment plant was designed and constructed by
IVC laboratory and Environmental Services, Chennai, Tamil Nadu, India.
167
where, K i is the inhibition coefficient (mg/l). The biokinetic parameters in this model
were estimated by the Lineweaver–Burk plot (1/μ vs. 1/S) (Najafpour 2007). Also,
the most important factor in biodegradation process was determined by Friedman
test by use of the statistical package SPSS.
2.5 Lab Scale Study for Removal of Nitrate in Drinking Water
The lab scale setup consists of reservoir, reactor tank, settling tank, filtration tank and
collection tank (Fig. 1). The reactor and settling tanks were fitted with stirrer. The
filtration tank was made of rectangular glass vessel with dimension of 55 cm in height,
60 cm in length and 35 cm in width. To this, large pebbles (2.0 to 2.5 cm) were packed
in bottom of the vessel followed by small pebbles (0.7–1.5 cm), gravel (0.4–0.6 cm),
coarse sand (0.05–0.1 cm), fine sand (0.15–0.3 mm) and activated carbon (0.75–
1.0 μm). The filtration tank was washed thoroughly with sterile distilled water to
remove the adhering particles in the filter bed. The bottom of the vessel was connected
with an outlet to a collection tank.
About 10 L of fresh drinking water with 100 mg/L of NO 3
− was added to the
reactor tank. Further, 1% of soluble starch and 10 mL of KW1 and YW4 (1:1 v/v)
containing 10
4 CFU/mL were added and allowed to react for 48 h at an optimum
temperature of 30 °C and pH 7. The speed of stirrer in both reactor and settling tank
was adjusted to 120 rpm. After bacterial treatment, the water sample was transferred
to settling tank and mixed thoroughly with commercial grade alum [(Al 2 (SO 4 ) 3 ] and
lime [CaCO 3 ], at normal dosage (alum—25 mg/L and lime—6 mg/L) prescribed by
Central Pollution Control Board, India, for 15 min at 120 rpm and 10 min at 15 rpm
and allowed to settle for 30 min (Ayyasamy et al. 2007). Further, the bacterial biomass
and coagulant particles were removed through the outlet of settling tank followed by
filtration. The bacterial growth, amount of NO 3
− , NO 2
− and NH 4
+ were estimated
in the treated water sample for every 6 h (APHA 2005).
2.6 Pilot Scale Study for Removal of Nitrate in Drinking
Water
The pilot scale plant consists of reservoir (1000 L), inoculum tank (10 L), reactor tank
(1200 L), settling tank (1200 L), sand filter (1200 L) (mode of packing was similar as
mentioned in Sect. 2.4) and collection tank (1200 L). Each tank was interconnected
with pipelines as shown in the Fig. 2. The reactor tank was fitted with peddler to
mix bacterial inoculum with water. The settling tank was also fitted with peddler for
mixing of coagulating agents. The treatment plant was designed and constructed by
IVC laboratory and Environmental Services, Chennai, Tamil Nadu, India.