10 Review on Trends in the Removal of Pharmaceuticals …
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efficiency between 50 and 70% during the flocculation test. The other pollutants
showed removal efficiency less than 25%. Also, carbamazepine and ibuprofen were
not removed from water.
10.5.2 Activated Sludge Process
Activated sludge process is a biological treatment widely used in conventional
wastewater treatment plants (WWTPs). Though volatilization, adsorption, and
biodegradation are important steps of activated sludge process, reports indicated that
volatilization and adsorption have least contributions for PPCPs removal (Gobel et al.
2005; Suarez et al. 2010; Li et al. 2015). Biodegradation is the main mechanisms for
the activated sludge-based process. However, many factors like pH, effectiveness of
the degraders, and retention time affect the PPCPs removal efficiency in this process.
Ternes et al. (2007) tried to remove diclofenac, clofibrate acid, ibuprofen, ifosfamide,
and cyclophosphamide using activated sludge process and found very low removal
efficiency. Song et al. (2009) on the other hand found that for efficient PPCPs degradation sufficient retention time. They also pointed out that existing sewage treatment
plants have very short retention time which is not sufficient for the degradation of
PPCPs at the operational process. On the other hand, Wang et al. (2002) indicated
that low abundance of degraders and the lack of degraders in the environment could
also lower the efficiency of activated sludge process. They prescribed biological
acclimation and bio-augmentation to tackle these issues.
10.5.3 Advanced Oxidation Technology
10.5.3.1 Ozonation
Oxidation of organic pollutants with ozone is one of the most studied processes.
Ozone has been widely used for the removal of PPCPs. The rate of ozonation mainly
depends on the formation of hydroxyl radicals. Thus, to enhance the oxidation efficacy H 2 O 2 is being used with ozone very frequently for eliminating PPCPs from water
(Bai et al. 2016). The reviews of Esplugas et al. (2007) and Wang and Chu (2016)
indicated that ozone has very high PPCPs oxidizing abilities. However, these reviews
also pointed out that ozonation rate could be declined dramatically if hydroxyl radical scavengers are present in the mixture. Also, wastewater is a complex system with
different types of pollutants; thus, detail study is needed to investigate the effect of
wastewater composition on the hydroxyl radical formation.
Ternes et al.(2007) used ozone in their study to remove carbamazepine, diclofenac,
solid alkyd resin, and oxcarbazepine from raw water. They found that addition of
ozone in the range of 0.5 mg/L could remove almost 97% of carbamazepine and
diclofenac from water. O 3 /H 2 O 2 was also used for PPCPs oxidation (Zwiener and
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efficiency between 50 and 70% during the flocculation test. The other pollutants
showed removal efficiency less than 25%. Also, carbamazepine and ibuprofen were
not removed from water.
10.5.2 Activated Sludge Process
Activated sludge process is a biological treatment widely used in conventional
wastewater treatment plants (WWTPs). Though volatilization, adsorption, and
biodegradation are important steps of activated sludge process, reports indicated that
volatilization and adsorption have least contributions for PPCPs removal (Gobel et al.
2005; Suarez et al. 2010; Li et al. 2015). Biodegradation is the main mechanisms for
the activated sludge-based process. However, many factors like pH, effectiveness of
the degraders, and retention time affect the PPCPs removal efficiency in this process.
Ternes et al. (2007) tried to remove diclofenac, clofibrate acid, ibuprofen, ifosfamide,
and cyclophosphamide using activated sludge process and found very low removal
efficiency. Song et al. (2009) on the other hand found that for efficient PPCPs degradation sufficient retention time. They also pointed out that existing sewage treatment
plants have very short retention time which is not sufficient for the degradation of
PPCPs at the operational process. On the other hand, Wang et al. (2002) indicated
that low abundance of degraders and the lack of degraders in the environment could
also lower the efficiency of activated sludge process. They prescribed biological
acclimation and bio-augmentation to tackle these issues.
10.5.3 Advanced Oxidation Technology
10.5.3.1 Ozonation
Oxidation of organic pollutants with ozone is one of the most studied processes.
Ozone has been widely used for the removal of PPCPs. The rate of ozonation mainly
depends on the formation of hydroxyl radicals. Thus, to enhance the oxidation efficacy H 2 O 2 is being used with ozone very frequently for eliminating PPCPs from water
(Bai et al. 2016). The reviews of Esplugas et al. (2007) and Wang and Chu (2016)
indicated that ozone has very high PPCPs oxidizing abilities. However, these reviews
also pointed out that ozonation rate could be declined dramatically if hydroxyl radical scavengers are present in the mixture. Also, wastewater is a complex system with
different types of pollutants; thus, detail study is needed to investigate the effect of
wastewater composition on the hydroxyl radical formation.
Ternes et al.(2007) used ozone in their study to remove carbamazepine, diclofenac,
solid alkyd resin, and oxcarbazepine from raw water. They found that addition of
ozone in the range of 0.5 mg/L could remove almost 97% of carbamazepine and
diclofenac from water. O 3 /H 2 O 2 was also used for PPCPs oxidation (Zwiener and