wastewater [102–104]. The results indicated that activated carbon could be
employed for efficient removal of dyes from wastewater [104–106].
PAC (powdered activated carbon) and GAC are frequently applied in drinking
water treatment for removal of natural or synthetic organic compounds (SOCs), e.g.,
pesticides [107]. Recently several studies have evaluated adsorption of other trace
organics (PhACs, EDCs) on activated carbon both under laboratory conditions and
surveys at full-scale drinking water treatment plants [108, 109]. For example,
Hernández-Leal et al. [110] reported complete adsorption of all studied trace
organics
(bisphenol-A,
benzophenone-3,
hexylcinnamic
aldehyde,
4-methylbenzylidene-camphor (4MBC), triclosan, galaxolide, and ethylhexyl
methoxycinnamate) onto PAC in batch tests with Milli-Q water spiked with
100–1,600 μg/L of trace organics at a PAC dosage of 1.25 g/L and contact time of
5 min.
GAC has a relatively larger particle size compared to PAC and, consequently,
presents a relatively smaller surface area. Nevertheless, GAC has long been used in
the removal of traditional organic contaminants such as pesticides [107]. GAC has
been proposed as a potential treatment method to aid in the effective removal of
emerging contaminants, particularly EDCs in wastewater treatment. A significant
reduction in the concentration of steroidal estrogens (43–64%) and mebeverine
(84–99%) has been achieved in a full-scale granular activated carbon plant
[111]. In a study by Hernández-Leal et al. [110], three GAC columns were operated
to treat aerobically treated gray water which was spiked with the above emerging
contaminants in the range of 0.1–10 μg/L at a flow rate of 0.5 bed volumes (BV)/h.
They observed more than 72% removal of all compounds (bisphenol-A,
hexylcinnamic aldehyde, 4-methylbenzylidene-camphor (4MBC), benzophenone-3
(BP3), triclosan, galaxolide, and ethylhexyl methoxycinnamate). Tanghe and
Verstraete [112] reported that at least 100 mg/g of nonylphenol is adsorbed on
GAC in an adsorption test. A few studies have investigated GAC adsorption as an
option for tertiary treatment of conventional biologically treated wastewater
[111, 113]; for example, Grover et al. [111] reported that a full-scale GAC plant
could reduce above 60% of steroidal estrogens in sewage effluent.
Activated carbon adsorption can be coupled with a biological treatment in two
different configurations: (1) addition of powdered activated carbon (PAC) directly in
the bioreactor [114–117] and (2) posttreatment of the bioreactor (e.g., MBR) permeate using either a granular activated carbon (GAC) column [118, 119] or a
continuously mixed reactor containing a slurry of PAC [120]. Research results
have suggested that addition of PAC enhanced NSAID removal by initial adsorption
and subsequently enhanced contact time with biological agents in the reactor for
biodegradation. While the removal by initial adsorption has been easily demonstrated in a number of studies, the enhancement of biodegradation is an assumption.
Nguyen et al. [21] observed an immediate improvement in naproxen, diclofenac,
ketoprofen, and ibuprofen removal after PAC addition to the MBR. The NSAID
adsorbed onto PAC can be efficiently removed by the PAC–MBR system because of
the complete retention of the sludge by the membrane [21, 114].
Contemporary Methods for Removal of Nonsteroidal Anti-inflammatory Drugs in. . .
231
employed for efficient removal of dyes from wastewater [104–106].
PAC (powdered activated carbon) and GAC are frequently applied in drinking
water treatment for removal of natural or synthetic organic compounds (SOCs), e.g.,
pesticides [107]. Recently several studies have evaluated adsorption of other trace
organics (PhACs, EDCs) on activated carbon both under laboratory conditions and
surveys at full-scale drinking water treatment plants [108, 109]. For example,
Hernández-Leal et al. [110] reported complete adsorption of all studied trace
organics
(bisphenol-A,
benzophenone-3,
hexylcinnamic
aldehyde,
4-methylbenzylidene-camphor (4MBC), triclosan, galaxolide, and ethylhexyl
methoxycinnamate) onto PAC in batch tests with Milli-Q water spiked with
100–1,600 μg/L of trace organics at a PAC dosage of 1.25 g/L and contact time of
5 min.
GAC has a relatively larger particle size compared to PAC and, consequently,
presents a relatively smaller surface area. Nevertheless, GAC has long been used in
the removal of traditional organic contaminants such as pesticides [107]. GAC has
been proposed as a potential treatment method to aid in the effective removal of
emerging contaminants, particularly EDCs in wastewater treatment. A significant
reduction in the concentration of steroidal estrogens (43–64%) and mebeverine
(84–99%) has been achieved in a full-scale granular activated carbon plant
[111]. In a study by Hernández-Leal et al. [110], three GAC columns were operated
to treat aerobically treated gray water which was spiked with the above emerging
contaminants in the range of 0.1–10 μg/L at a flow rate of 0.5 bed volumes (BV)/h.
They observed more than 72% removal of all compounds (bisphenol-A,
hexylcinnamic aldehyde, 4-methylbenzylidene-camphor (4MBC), benzophenone-3
(BP3), triclosan, galaxolide, and ethylhexyl methoxycinnamate). Tanghe and
Verstraete [112] reported that at least 100 mg/g of nonylphenol is adsorbed on
GAC in an adsorption test. A few studies have investigated GAC adsorption as an
option for tertiary treatment of conventional biologically treated wastewater
[111, 113]; for example, Grover et al. [111] reported that a full-scale GAC plant
could reduce above 60% of steroidal estrogens in sewage effluent.
Activated carbon adsorption can be coupled with a biological treatment in two
different configurations: (1) addition of powdered activated carbon (PAC) directly in
the bioreactor [114–117] and (2) posttreatment of the bioreactor (e.g., MBR) permeate using either a granular activated carbon (GAC) column [118, 119] or a
continuously mixed reactor containing a slurry of PAC [120]. Research results
have suggested that addition of PAC enhanced NSAID removal by initial adsorption
and subsequently enhanced contact time with biological agents in the reactor for
biodegradation. While the removal by initial adsorption has been easily demonstrated in a number of studies, the enhancement of biodegradation is an assumption.
Nguyen et al. [21] observed an immediate improvement in naproxen, diclofenac,
ketoprofen, and ibuprofen removal after PAC addition to the MBR. The NSAID
adsorbed onto PAC can be efficiently removed by the PAC–MBR system because of
the complete retention of the sludge by the membrane [21, 114].
Contemporary Methods for Removal of Nonsteroidal Anti-inflammatory Drugs in. . .
231