164
R. Sundaram et al.
1 Introduction
Nitrate (NO 3
− )in drinking water often causes methemoglobinemia and other health
disorders such as hypertension, increased infant mortality, goiter, stomach cancer,
thyroid disorder, cytogenetic defects and birth defects (WHO 2003). During the
last two decades, extensive attention has been paid to the management and control
of nitrate contamination. As nitrate is stable and highly soluble ion and has a low
potential for adsorption or co-precipitation, it is difficult to remove NO 3
− by conventional water treatment processes including lime softening and filtration (Kapoor and
Viraraghavan 1997).Although, reverse osmosis (Schoeman and Steyn 2003), ion
exchange (Matosicet al., 2000; Kim and Benjamin 2004),catalytic reduction (Reddy
and Lin 2000; Sunet al., 2010), electrodialysis (Elmidaouiet al., 2001), electroccoagulation (Jeonget al., 2014), adsorption process (Hamoudi and Belkacemi 2013), chemical denitrification (Mortazaviet al. 2011) and phytoremediation (Ayyasamyet al.,
2009) are effective in removing NO 3
− from contaminated water, but they are very
expensive with a limited potential application (Kesseruet al., 2002). The most versatile and widely used technology in the removal of NO 3
− from water and/or wastewater
is microbiological denitrification (Shin and Cha 2008).
Biological denitrification performed with bacteria can be involved in autotrophic
and heterotrophic ways. However, the biological system needs essential electron
donors to reduceNO 3
− from drinking water. Many workers have used a variety of
carbon sources as an electron donor toenhance the microbial growth for theremoval
of NO 3
− . Gomez et al. (2000) found that ethanol was the suitable carbon source
among studied the effect of sucrose, ethanol and methanol for the removal of NO 3
−
from contaminated groundwater. Shanthi et al. (2005) reported 95 to 100% reduction
when methanol was used as a carbon source. Akunnaet al. (1994) showed that glucose
induced a very high degree of NO 3
− removal in aaqueous mediumunder anaerobic
condition. Kim et al. (2002) reported thatnitrogen removal efficiency of 99.5% at a
hydraulic residence time of 1 h while starch was supplemented to groundwater. In
a study conducted by Fernandez-Nava et al. (2010), three different carbon sources
namely, wastewater from sweet manufacturing, saccharose-rich residue from the
production of soft drinks and lactic acid-rich residue from a dairy plant were investigated for their potential use in nitrate reduction from wastewater. Authors found
that there was maximum nitrate removal efficiency using the wastewater of sweet
production and saccharose-rich residue in short time. Thus, in this study, commercially available carbon sources such as glucose, starch, cellulose, sucrose and acetic
acid were tested for their involvement in the removal of NO 3
− from drinking water.
The major issue in biological methodis the removal of bacterial cells and
suspended particles. Coagulating agents have been widely applied to remove chemical ions, colloidal particles and microorganisms (Jiang et al. 2006; Ayyasamy et al.
2007). Several authors have studied biological and chemical treatment separatelyfor
the removal of NO 3
− and microorganisms from the water system. However, combined
treatment system of microorganisms and coagulants on the removal of NO 3
− was not
R. Sundaram et al.
1 Introduction
Nitrate (NO 3
− )in drinking water often causes methemoglobinemia and other health
disorders such as hypertension, increased infant mortality, goiter, stomach cancer,
thyroid disorder, cytogenetic defects and birth defects (WHO 2003). During the
last two decades, extensive attention has been paid to the management and control
of nitrate contamination. As nitrate is stable and highly soluble ion and has a low
potential for adsorption or co-precipitation, it is difficult to remove NO 3
− by conventional water treatment processes including lime softening and filtration (Kapoor and
Viraraghavan 1997).Although, reverse osmosis (Schoeman and Steyn 2003), ion
exchange (Matosicet al., 2000; Kim and Benjamin 2004),catalytic reduction (Reddy
and Lin 2000; Sunet al., 2010), electrodialysis (Elmidaouiet al., 2001), electroccoagulation (Jeonget al., 2014), adsorption process (Hamoudi and Belkacemi 2013), chemical denitrification (Mortazaviet al. 2011) and phytoremediation (Ayyasamyet al.,
2009) are effective in removing NO 3
− from contaminated water, but they are very
expensive with a limited potential application (Kesseruet al., 2002). The most versatile and widely used technology in the removal of NO 3
− from water and/or wastewater
is microbiological denitrification (Shin and Cha 2008).
Biological denitrification performed with bacteria can be involved in autotrophic
and heterotrophic ways. However, the biological system needs essential electron
donors to reduceNO 3
− from drinking water. Many workers have used a variety of
carbon sources as an electron donor toenhance the microbial growth for theremoval
of NO 3
− . Gomez et al. (2000) found that ethanol was the suitable carbon source
among studied the effect of sucrose, ethanol and methanol for the removal of NO 3
−
from contaminated groundwater. Shanthi et al. (2005) reported 95 to 100% reduction
when methanol was used as a carbon source. Akunnaet al. (1994) showed that glucose
induced a very high degree of NO 3
− removal in aaqueous mediumunder anaerobic
condition. Kim et al. (2002) reported thatnitrogen removal efficiency of 99.5% at a
hydraulic residence time of 1 h while starch was supplemented to groundwater. In
a study conducted by Fernandez-Nava et al. (2010), three different carbon sources
namely, wastewater from sweet manufacturing, saccharose-rich residue from the
production of soft drinks and lactic acid-rich residue from a dairy plant were investigated for their potential use in nitrate reduction from wastewater. Authors found
that there was maximum nitrate removal efficiency using the wastewater of sweet
production and saccharose-rich residue in short time. Thus, in this study, commercially available carbon sources such as glucose, starch, cellulose, sucrose and acetic
acid were tested for their involvement in the removal of NO 3
− from drinking water.
The major issue in biological methodis the removal of bacterial cells and
suspended particles. Coagulating agents have been widely applied to remove chemical ions, colloidal particles and microorganisms (Jiang et al. 2006; Ayyasamy et al.
2007). Several authors have studied biological and chemical treatment separatelyfor
the removal of NO 3
− and microorganisms from the water system. However, combined
treatment system of microorganisms and coagulants on the removal of NO 3
− was not