170
R. Sundaram et al.
filter cum purifier (Model—Aquaguard—Nova, Model type—AGWPNOVA, Serial
No: BG03-005,504, Dimension—395 × 300 × 255 mm). After the above disinfection methods,the samples were collected and bacterial cells were enumerated by pour
plate technique. For chlorination, about 100 ml of the sample was taken in separate
conical flasks and 0.1, 0.2, 0.3, 0.4 and 0.5 mg/Lof residual chlorine (commercial
bleaching powder) was added. The bacterial populations were estimated at regular
intervals.
2.8 Statistical Analysis
The relationship between the bacterial growth, concentration of nitrate, nitrite and
ammonium was determined by Pearson correlation coefficient in terms of percentage
difference using SPSS software package. Further, the mean and standard deviation of
the physic-chemical parameters of water samples were calculated using the statistical
package within Microsoft® Excel Version 2010.
3 Results
3.1 Nitrate Reducing Bacteria in Water and Sediment
Samples
The bacterial species of Pseudomonas, Bacillus, Moroxella, Micrococcus, Alcaligenes, Corynebacteriumand members of Enterobacteriaceae were isolated from
water and sediment samples of Kodaikanal and Yercaud Lake. The ability of NO 3
−
reduction was tested using potassium nitrate broth and the results were given in Table
1. Among them,Pseudomonassp. (KW1) and Bacillus sp. (YW4) were found to be
the most efficient bacteria in removing NO 3
− . The consortium of KW1 and YW4
was further tested for the removal of NO 3
− .
3.2 Batch Mode Study for the Removal of Nitrate
in the Synthetic Medium
The maximum removal of NO 3
− from 100 to 0.6 mg/L was recorded in the synthetic
medium supplemented with starch (Fig. 3a) followed by glucose (100–18.35 mg/L).
The NO 3
− reduction in the presence of acetic acid, cellulose and sucrose was 100–
27.7, 100–34.8 and 100–44.9 mg/L respectively. The study conducted in the synthetic
medium with starch at various concentrations showed that at 1% starch the consortium KW1 + YW4 reduced maximum level of NO 3
− (100–0.58 mg/L) at 48 h of
R. Sundaram et al.
filter cum purifier (Model—Aquaguard—Nova, Model type—AGWPNOVA, Serial
No: BG03-005,504, Dimension—395 × 300 × 255 mm). After the above disinfection methods,the samples were collected and bacterial cells were enumerated by pour
plate technique. For chlorination, about 100 ml of the sample was taken in separate
conical flasks and 0.1, 0.2, 0.3, 0.4 and 0.5 mg/Lof residual chlorine (commercial
bleaching powder) was added. The bacterial populations were estimated at regular
intervals.
2.8 Statistical Analysis
The relationship between the bacterial growth, concentration of nitrate, nitrite and
ammonium was determined by Pearson correlation coefficient in terms of percentage
difference using SPSS software package. Further, the mean and standard deviation of
the physic-chemical parameters of water samples were calculated using the statistical
package within Microsoft® Excel Version 2010.
3 Results
3.1 Nitrate Reducing Bacteria in Water and Sediment
Samples
The bacterial species of Pseudomonas, Bacillus, Moroxella, Micrococcus, Alcaligenes, Corynebacteriumand members of Enterobacteriaceae were isolated from
water and sediment samples of Kodaikanal and Yercaud Lake. The ability of NO 3
−
reduction was tested using potassium nitrate broth and the results were given in Table
1. Among them,Pseudomonassp. (KW1) and Bacillus sp. (YW4) were found to be
the most efficient bacteria in removing NO 3
− . The consortium of KW1 and YW4
was further tested for the removal of NO 3
− .
3.2 Batch Mode Study for the Removal of Nitrate
in the Synthetic Medium
The maximum removal of NO 3
− from 100 to 0.6 mg/L was recorded in the synthetic
medium supplemented with starch (Fig. 3a) followed by glucose (100–18.35 mg/L).
The NO 3
− reduction in the presence of acetic acid, cellulose and sucrose was 100–
27.7, 100–34.8 and 100–44.9 mg/L respectively. The study conducted in the synthetic
medium with starch at various concentrations showed that at 1% starch the consortium KW1 + YW4 reduced maximum level of NO 3
− (100–0.58 mg/L) at 48 h of