triclosan), two compounds (nadolol and sotalol) below 20%, and three compounds
(carbamazepine, gemfibrozil and trimethoprim) showed both positive and negative
removals depending on the original study. The amount of results was limited to
allow a proper comparison of CW designs. None of the systems reported was a
French system nor, to the best of my knowledge, a French system has been studied
for the removal of pharmaceuticals. Overall, Verlicchi and Zambello [27] concluded
that CWs provide comparable efficiencies at the secondary treatment level to
conventional WWTPs for the removal of many common pharmaceuticals, including
caffeine, ibuprofen, naproxen and salicylic acid. One of the knowledge gaps identified was the need to optimize the removal of the most critical compounds, mainly
antibiotics and some analgesics and anti-inflammatories [27].
Other brief mentions to pharmaceuticals and CWS can also be found in a couple
of later reviews [51–55]. Melvin and Leusch [56] provide an interesting comparison
of CWs with other wastewater treatment technology, where “ponds and CWs”
continued to be considered at least as efficient as classical activated sludge systems.
However, results were not statistically better than other alternative technologies,
oxidation ditch and membrane bioreactor, probably due to generalization of the
datasets (grouping of efficiency for different compounds and independently of
specific technology designs). Vo et al. [57] aimed at going beyond removal efficiency and focused on the removal mechanisms of pharmaceutical and personal care
products in CWs. Zhou et al. [58] have reviewed chiral pharmaceuticals in the
environment and remediation technologies applied for their treatment, including a
small section dedicated to CWs. In spite of the interesting title, the work does not
provide details about chiral processes. Rabello et al. [59] reviewed the combination
of CWs and algae systems. The latter were considered more efficient than CWs in
removing the most commonly studied compounds, i.e. caffeine, carbamazepine,
diclofenac, ibuprofen, ketoprofen and naproxen, than the CWs. Nevertheless, the
combination of both systems was proposed as an effective alternative for removing
pharmaceuticals from domestic wastewater [59]. Nguyen et al. [60] surveyed literature investigating plant-based remediation practices, especially CWs, to remove
pharmaceuticals and personal care products. They have expanded their overview
towards the plant-bacteria synergism: the microbes (both rhizo- and endophytes) in
CWs not only degrade the compounds directly but also accelerate plant growth by
producing growth-promoting enzymes and hence increasing the remediation potential [60]. More details in Sect. 3.
Liu et al. [61] are the only review specifically dedicated to antibiotics and
antibiotic-resistant bacteria, covering a good amount of literature. The removal
efficiency of CWs for antibiotics showed good performance (average value above
50%), especially VF (average value of 80%). The removal efficiencies of sulfonamide and macrolide antibiotics were lower than those of tetracycline and quinolone
antibiotics, stressing again compound-dependency of the performance. Regarding
the antibiotic resistance genes, HSSF had better performance (above 50%) than VF,
especially for sulfonamide resistance genes [61].
Most recently, two review works have been published [28, 62] making use of the,
so far, most complete data collection on the topic (more than 60 papers). Their earlier
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P. N. Carvalho
(carbamazepine, gemfibrozil and trimethoprim) showed both positive and negative
removals depending on the original study. The amount of results was limited to
allow a proper comparison of CW designs. None of the systems reported was a
French system nor, to the best of my knowledge, a French system has been studied
for the removal of pharmaceuticals. Overall, Verlicchi and Zambello [27] concluded
that CWs provide comparable efficiencies at the secondary treatment level to
conventional WWTPs for the removal of many common pharmaceuticals, including
caffeine, ibuprofen, naproxen and salicylic acid. One of the knowledge gaps identified was the need to optimize the removal of the most critical compounds, mainly
antibiotics and some analgesics and anti-inflammatories [27].
Other brief mentions to pharmaceuticals and CWS can also be found in a couple
of later reviews [51–55]. Melvin and Leusch [56] provide an interesting comparison
of CWs with other wastewater treatment technology, where “ponds and CWs”
continued to be considered at least as efficient as classical activated sludge systems.
However, results were not statistically better than other alternative technologies,
oxidation ditch and membrane bioreactor, probably due to generalization of the
datasets (grouping of efficiency for different compounds and independently of
specific technology designs). Vo et al. [57] aimed at going beyond removal efficiency and focused on the removal mechanisms of pharmaceutical and personal care
products in CWs. Zhou et al. [58] have reviewed chiral pharmaceuticals in the
environment and remediation technologies applied for their treatment, including a
small section dedicated to CWs. In spite of the interesting title, the work does not
provide details about chiral processes. Rabello et al. [59] reviewed the combination
of CWs and algae systems. The latter were considered more efficient than CWs in
removing the most commonly studied compounds, i.e. caffeine, carbamazepine,
diclofenac, ibuprofen, ketoprofen and naproxen, than the CWs. Nevertheless, the
combination of both systems was proposed as an effective alternative for removing
pharmaceuticals from domestic wastewater [59]. Nguyen et al. [60] surveyed literature investigating plant-based remediation practices, especially CWs, to remove
pharmaceuticals and personal care products. They have expanded their overview
towards the plant-bacteria synergism: the microbes (both rhizo- and endophytes) in
CWs not only degrade the compounds directly but also accelerate plant growth by
producing growth-promoting enzymes and hence increasing the remediation potential [60]. More details in Sect. 3.
Liu et al. [61] are the only review specifically dedicated to antibiotics and
antibiotic-resistant bacteria, covering a good amount of literature. The removal
efficiency of CWs for antibiotics showed good performance (average value above
50%), especially VF (average value of 80%). The removal efficiencies of sulfonamide and macrolide antibiotics were lower than those of tetracycline and quinolone
antibiotics, stressing again compound-dependency of the performance. Regarding
the antibiotic resistance genes, HSSF had better performance (above 50%) than VF,
especially for sulfonamide resistance genes [61].
Most recently, two review works have been published [28, 62] making use of the,
so far, most complete data collection on the topic (more than 60 papers). Their earlier
390
P. N. Carvalho