membrane with respect to ammoniacal nitrogen. Results regarding removal of
ammoniacal nitrogen and total nitrogen were found to be 95–98% and 80–99%,
respectively (Albornoz et al. 2019). Additionally, electrodialysis requires very few
pretreatments to reduce fouling of membrane as compared to reverse osmosis and
thus owing to reverse polarity operation (Strathmann 2010). This technique does not
need osmotic pressure and has low investment in terms of feed and energy. The main
drawback of this method is that it removes only ions and is not effective against
microorganisms and organic compounds which have been produced during this
process. In addition, when the salt concentration of effluent is increased, it involves
high energy investment.
7.3.2 Chemical Processes
Chemical methods involve complete mineralization and degradation of the nitrogenous waste and hence are deemed to be robust, reliable, and effective. Methods such
as advanced oxidation processes (AOPs) are increasingly becoming popular these
days. Chemical species such as ozone, chlorine, and hydrogen peroxide are commonly employed as an oxidant, and AOPs such as Fenton oxidation and electrochemical oxidation involve a combination of one or more of these oxidants with
transition metals or metal oxide. The primary goal of chemical oxidation process is
to mineralize the contaminants and convert it into water, nitrogen, and other minerals. To run the oxidation processes, energy source such as electric current, gamma
radiation, ultrasonic, and UV-Vis radiation is needed (Ikehata et al. 2008). The
aforementioned processes are commonly used for the treatment of wastewater.
7.3.2.1 Fenton Oxidation
Contaminants derived from pharmaceutical, pesticide, tannery, and textile industries
are having ample amount of ammoniacal nitrogen, which can be effectively
transformed to nitrogen and nitrate with the help of the Fenton process (Dantas
et al. 2003). Ammoniacal nitrogen is one of the primary pollutants present in tannery
wastewater and its concentration in untreated effluent is higher than 100 mg/L
(Wang et al. 2012). Fenton oxidation is an oxidation process involving the formation
of hydroxyl radical from a reaction between iron and hydrogen peroxide, in which
ferrous can be regenerated as depicted by Eqs. 7.1 and 7.2 (Shemer et al. 2006).
Reaction (7.2) being very slow results in the accumulation of ferric (Fe
3+ ) in the
solution, which further precipitates as Fe(OH) 3 (de Luna et al. 2012). This inherently
leads to reduction in the treatment efficiency due to the removal of iron from the
solution. Moreover, it entails significant amount of addition of the reagent, resulting
in enhanced operational cost.
7 Nitrogenous Wastes and Its Efficient Treatment in Wastewater
153
ammoniacal nitrogen and total nitrogen were found to be 95–98% and 80–99%,
respectively (Albornoz et al. 2019). Additionally, electrodialysis requires very few
pretreatments to reduce fouling of membrane as compared to reverse osmosis and
thus owing to reverse polarity operation (Strathmann 2010). This technique does not
need osmotic pressure and has low investment in terms of feed and energy. The main
drawback of this method is that it removes only ions and is not effective against
microorganisms and organic compounds which have been produced during this
process. In addition, when the salt concentration of effluent is increased, it involves
high energy investment.
7.3.2 Chemical Processes
Chemical methods involve complete mineralization and degradation of the nitrogenous waste and hence are deemed to be robust, reliable, and effective. Methods such
as advanced oxidation processes (AOPs) are increasingly becoming popular these
days. Chemical species such as ozone, chlorine, and hydrogen peroxide are commonly employed as an oxidant, and AOPs such as Fenton oxidation and electrochemical oxidation involve a combination of one or more of these oxidants with
transition metals or metal oxide. The primary goal of chemical oxidation process is
to mineralize the contaminants and convert it into water, nitrogen, and other minerals. To run the oxidation processes, energy source such as electric current, gamma
radiation, ultrasonic, and UV-Vis radiation is needed (Ikehata et al. 2008). The
aforementioned processes are commonly used for the treatment of wastewater.
7.3.2.1 Fenton Oxidation
Contaminants derived from pharmaceutical, pesticide, tannery, and textile industries
are having ample amount of ammoniacal nitrogen, which can be effectively
transformed to nitrogen and nitrate with the help of the Fenton process (Dantas
et al. 2003). Ammoniacal nitrogen is one of the primary pollutants present in tannery
wastewater and its concentration in untreated effluent is higher than 100 mg/L
(Wang et al. 2012). Fenton oxidation is an oxidation process involving the formation
of hydroxyl radical from a reaction between iron and hydrogen peroxide, in which
ferrous can be regenerated as depicted by Eqs. 7.1 and 7.2 (Shemer et al. 2006).
Reaction (7.2) being very slow results in the accumulation of ferric (Fe
3+ ) in the
solution, which further precipitates as Fe(OH) 3 (de Luna et al. 2012). This inherently
leads to reduction in the treatment efficiency due to the removal of iron from the
solution. Moreover, it entails significant amount of addition of the reagent, resulting
in enhanced operational cost.
7 Nitrogenous Wastes and Its Efficient Treatment in Wastewater
153