of the membrane is compromised due to precipitation of salts (calcium sulfate and
calcium chloride), thereby leading to fouling (Hasson et al. 2001).
7.3.1.2 Ion Exchange
During ion-exchange process, reversible interchange of ions between two phases,
i.e., solid and liquid, takes place in which moving ions of ion-exchange membrane
get exchanged with the adjacent medium (Bashir et al. 2010). Ion-exchange resins
have been used for treatment of wastewater consisting of different functional groups
and ions. When nitrogenous waste derived from landfill leachate was passed through
natural zeolite, Dowex 50W-X8, and Purolite MN 500 resin beads, enhanced
ammonium ion uptake was observed on addition of Na
+ ion and citric acid
(Jorgensen and Weatherley 2003). Results indicated that the uptake of ammonium
was highest with Dowex 50W-X8 followed by Purolite MN 500 and lowest in case
of natural zeolite (Jorgensen and Weatherley 2003). This process can also remove
sulfate along with nitrate ions, prevalently found in fertilizer wastewater (Leaković
et al. 2000). Furthermore, exhausted resin can be regenerated with NaCl by
displacing negatively charged ions to chloride ions (Roquebert et al. 2000). However, the discharge of toxic ions such as calcium, phosphate, magnesium, and
fluoride should be taken into account, as it contributes to extra operational cost in
this process (Shrimali and Singh 2001; Karanasios et al. 2010).
7.3.1.3 Electrodialysis
Electrodialysis (ED) is a membrane technique used to separate charged ions from
aqueous solution in the presence of electric potential gradient, which provides
driving force to separate the ions. Electrodialysis has been employed in large scale
(>20,000 m
3 d
À1 ) and found to be the most suitable technique for desalination and
demineralization of brackish and industrial process water (Strathmann 2010).
Ammonia-nitrogen-containing wastewater was applied to electrodialysis system,
and the performance of the system was evaluated through different factorially
designed experiments (Song et al. 2012). The experimental results showed that
optimum condition for ED, i.e., operation voltage and concentration ratio of two
cells, were obtained as 12 V and 1:3, respectively. In addition, removal of ammonianitrogen was also influenced by higher feed concentration of stream (Song et al.
2012). Electrodialysis can be a suitable option for low to high concentration of
nitrate-nitrogen in rural area, but maintenance and operation of electrodialysis are
difficult tasks (Schoeman 2009).
Electrodialysis can also be used in nutrient recovery from municipal wastewater.
The total concentration of ammonia-nitrogen was found to be 7100 Æ 300 mg/L
from concentrated product derived from wastewater dilute feed stream to product
stream (Ward et al. 2018). In another study, electrodialysis was employed to treat
university sewage water. The study was conducted to monitor the behavior of
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P. Chawley et al.
calcium chloride), thereby leading to fouling (Hasson et al. 2001).
7.3.1.2 Ion Exchange
During ion-exchange process, reversible interchange of ions between two phases,
i.e., solid and liquid, takes place in which moving ions of ion-exchange membrane
get exchanged with the adjacent medium (Bashir et al. 2010). Ion-exchange resins
have been used for treatment of wastewater consisting of different functional groups
and ions. When nitrogenous waste derived from landfill leachate was passed through
natural zeolite, Dowex 50W-X8, and Purolite MN 500 resin beads, enhanced
ammonium ion uptake was observed on addition of Na
+ ion and citric acid
(Jorgensen and Weatherley 2003). Results indicated that the uptake of ammonium
was highest with Dowex 50W-X8 followed by Purolite MN 500 and lowest in case
of natural zeolite (Jorgensen and Weatherley 2003). This process can also remove
sulfate along with nitrate ions, prevalently found in fertilizer wastewater (Leaković
et al. 2000). Furthermore, exhausted resin can be regenerated with NaCl by
displacing negatively charged ions to chloride ions (Roquebert et al. 2000). However, the discharge of toxic ions such as calcium, phosphate, magnesium, and
fluoride should be taken into account, as it contributes to extra operational cost in
this process (Shrimali and Singh 2001; Karanasios et al. 2010).
7.3.1.3 Electrodialysis
Electrodialysis (ED) is a membrane technique used to separate charged ions from
aqueous solution in the presence of electric potential gradient, which provides
driving force to separate the ions. Electrodialysis has been employed in large scale
(>20,000 m
3 d
À1 ) and found to be the most suitable technique for desalination and
demineralization of brackish and industrial process water (Strathmann 2010).
Ammonia-nitrogen-containing wastewater was applied to electrodialysis system,
and the performance of the system was evaluated through different factorially
designed experiments (Song et al. 2012). The experimental results showed that
optimum condition for ED, i.e., operation voltage and concentration ratio of two
cells, were obtained as 12 V and 1:3, respectively. In addition, removal of ammonianitrogen was also influenced by higher feed concentration of stream (Song et al.
2012). Electrodialysis can be a suitable option for low to high concentration of
nitrate-nitrogen in rural area, but maintenance and operation of electrodialysis are
difficult tasks (Schoeman 2009).
Electrodialysis can also be used in nutrient recovery from municipal wastewater.
The total concentration of ammonia-nitrogen was found to be 7100 Æ 300 mg/L
from concentrated product derived from wastewater dilute feed stream to product
stream (Ward et al. 2018). In another study, electrodialysis was employed to treat
university sewage water. The study was conducted to monitor the behavior of
152
P. Chawley et al.