128
M. S. Miswan et al.
of ammonia nitrogen (AN) in lakes affected by agriculture activities. They reported
82.11% removal; however, this method is only applicable to water containing low
AN. Chen et al. on the other hand, claimed that chemical oxidation of ammonia
method removed 85% of ammonia nitrogen but the problem is still confined to the
level of the applied research.
Rysgaard et al. (1993) examined the nitrification and denitrification method in
lake and estuarine and obtained approximately 100% of nitrate removal. However,
this method may become complicated when applied to industrial wastewater due to
its various characteristics. Li et al. (2016) applied simultaneous nitrification and denitrification (SND) to remove total nitrogen up to 75.09%. This process is complicated
because it requires advanced bioreactor with adjustable aerobic, buffer and anoxic
zone with liquid circulation. Meanwhile, Sun et al. (2018) demonstrated autotrophic
denitrification method and the result was 98.1 ± 0.4% of nitrogen removal.
The current review discusses the performances of conventional methods in terms
of nitrogen removal including ammonia, nitrite and nitrate. Among the conventional
methods, nitrification and denitrification have high potential for nutrients removal.
They are environmentally friendly and cost-effective but these methods are timeconsuming. The advantages and disadvantages of nitrogen removal technologies are
listed in Table 8.2.
8.4.1 Nutrient Removal
Nutrient removal refers to the removal of nitrogen or phosphorus in the treatment of
the wastewater. Excessive nitrogen or phosphorus can cause nuisance growth of algae
or weeds in the receiving water. Discharges containing nitrogen and phosphorus may
accelerate the eutrophication of lakes and reservoirs and may stimulate the growth of
algae and rooted aquatic plants in shallow stream (Apandi et al. 2019). In addition,
the presence of algae and aquatic plants may interfere with the beneficial uses of
the water resources especially when they are used for water supplies (Abdel-Raouf
et al. 2012). Nitrogen in wastewater is mostly in the form of ammonia and organic
nitrogen. These nitrogen forms can be converted into nitrate nitrogen by bacteria,
if the plant is designed to provide enough oxygen with a long enough “sludge age”
to develop these slow-growing plant nutrient. The nitrate nitrogen is less toxic than
ammonia. If more complete removal of nitrogen is required, a biological process
can be set up. This biological setup can reduce the nitrate to nitrogen gas (and some
nitrous oxide). The nitrogen convention is shown in Fig. 8.2. Nitrification is the
biological oxidation of NH 4
+ to NO 3
− through a two-step autotrophic process by the
bacteria phosph and Nitrobacter (Zhang et al. 2018).
A two-step reaction is usually very rapid; hence, it is rare to find nitrite levels
higher than 1.0 mg/L in water (Luo et al. 2015). The nitrate formed by nitrification is
used by plants in the nitrogen cycle as a nitrogen source (synthesis) or reduced to N 2
gas through denitrification process. NO 3
− can be reduced under anoxic conditions
M. S. Miswan et al.
of ammonia nitrogen (AN) in lakes affected by agriculture activities. They reported
82.11% removal; however, this method is only applicable to water containing low
AN. Chen et al. on the other hand, claimed that chemical oxidation of ammonia
method removed 85% of ammonia nitrogen but the problem is still confined to the
level of the applied research.
Rysgaard et al. (1993) examined the nitrification and denitrification method in
lake and estuarine and obtained approximately 100% of nitrate removal. However,
this method may become complicated when applied to industrial wastewater due to
its various characteristics. Li et al. (2016) applied simultaneous nitrification and denitrification (SND) to remove total nitrogen up to 75.09%. This process is complicated
because it requires advanced bioreactor with adjustable aerobic, buffer and anoxic
zone with liquid circulation. Meanwhile, Sun et al. (2018) demonstrated autotrophic
denitrification method and the result was 98.1 ± 0.4% of nitrogen removal.
The current review discusses the performances of conventional methods in terms
of nitrogen removal including ammonia, nitrite and nitrate. Among the conventional
methods, nitrification and denitrification have high potential for nutrients removal.
They are environmentally friendly and cost-effective but these methods are timeconsuming. The advantages and disadvantages of nitrogen removal technologies are
listed in Table 8.2.
8.4.1 Nutrient Removal
Nutrient removal refers to the removal of nitrogen or phosphorus in the treatment of
the wastewater. Excessive nitrogen or phosphorus can cause nuisance growth of algae
or weeds in the receiving water. Discharges containing nitrogen and phosphorus may
accelerate the eutrophication of lakes and reservoirs and may stimulate the growth of
algae and rooted aquatic plants in shallow stream (Apandi et al. 2019). In addition,
the presence of algae and aquatic plants may interfere with the beneficial uses of
the water resources especially when they are used for water supplies (Abdel-Raouf
et al. 2012). Nitrogen in wastewater is mostly in the form of ammonia and organic
nitrogen. These nitrogen forms can be converted into nitrate nitrogen by bacteria,
if the plant is designed to provide enough oxygen with a long enough “sludge age”
to develop these slow-growing plant nutrient. The nitrate nitrogen is less toxic than
ammonia. If more complete removal of nitrogen is required, a biological process
can be set up. This biological setup can reduce the nitrate to nitrogen gas (and some
nitrous oxide). The nitrogen convention is shown in Fig. 8.2. Nitrification is the
biological oxidation of NH 4
+ to NO 3
− through a two-step autotrophic process by the
bacteria phosph and Nitrobacter (Zhang et al. 2018).
A two-step reaction is usually very rapid; hence, it is rare to find nitrite levels
higher than 1.0 mg/L in water (Luo et al. 2015). The nitrate formed by nitrification is
used by plants in the nitrogen cycle as a nitrogen source (synthesis) or reduced to N 2
gas through denitrification process. NO 3
− can be reduced under anoxic conditions