Combination of advanced biological systems and photocatalysis for the treatment of real hospital wastewater spiked with carbamazepine A pilot-scale study

Prévia do material em texto

Journal of Environmental Management 351 (2024) 119672
Available online 1 December 2023
0301-4797/© 2023 Elsevier Ltd. All rights reserved.
Research article 
Combination of advanced biological systems and photocatalysis for the 
treatment of real hospital wastewater spiked with carbamazepine: A 
pilot-scale study 
Abhradeep Majumder a, Philipp Otter b, Dominic Röher b, Amit Bhatnagar c, Nadeem Khalil d, 
Ashok Kumar Gupta e,*, Riccardo Bresciani f, Carlos A. Arias g 
a School of Environmental Science and Engineering, Indian Institute of Technology Kharagpur, Kharagpur, 721302, India 
b AUTARCON GmbH, D-34117, Kassel, Germany 
c Department of Separation Science, LUT School of Engineering Science, LUT University, Sammonkatu 12, Mikkeli, FI-50130, Finland 
d Environmental Engineering Section, Department of Civil Engineering Aligarh Muslim University, Aligarh, 202001, India 
e Environmental Engineering Division, Department of Civil Engineering, Indian Institute of Technology Kharagpur, Kharagpur, 721302, India 
f IRIDRA, Via Alfonso la Marmora, 51, 50121, Firenze, FI, Italy 
g Department of Biology, Aquatic Biology, Ole Worms Allé 1, Bldg 1135, Aarhus University, 8000, Aarhus C, Denmark 
A R T I C L E I N F O 
Handling editor: Raf Dewil 
Keywords: 
Moving bed biofilm reactor 
Pharmaceuticals 
Aerated constructed wetland 
Toxicity analysis 
Degradation pathway 
A B S T R A C T 
Over the past few decades, the increase in dependency on healthcare facilities has led to the generation of large 
quantities of hospital wastewater (HWW) rich in chemical oxygen demand (COD), total suspended solids (TSS), 
ammonia, recalcitrant pharmaceutically active compounds (PhACs), and other disease-causing microorganisms. 
Conventional treatment methods often cannot effectively remove the PhACs present in wastewater. Hence, 
hybrid processes comprising of biological treatment and advanced oxidation processes have been used recently 
to treat complex wastewater. The current study explores the performance of pilot-scale treatment of real HWW 
(3000 L/d) spiked with carbamazepine (CBZ) using combinations of moving and stationary bed bio-reactor- 
sedimentation tank (MBSST), aerated horizontal flow constructed wetland (AHFCW), and photocatalysis. The 
combination of MBSST and AHFCW could remove 85% COD, 93% TSS, 99% ammonia, and 30% CBZ. However, 
when the effluent of the AHFCW was subjected to photocatalysis, an enhanced CBZ removal of around 85% was 
observed. Furthermore, the intermediate products (IPs) formed after the photocatalysis was also less toxic than 
the IPs formed during the biological processes. The results of this study indicated that the developed pilot-scale 
treatment unit supplemented with photocatalysis could be used effectively to treat HWW. 
1. Introduction 
Hospitals generate a significant amount of wastewater due to their 
requirement in various healthcare-related activities. Hospital waste-
water (HWW) comprises antibiotic-resistant genes, infectious microor-
ganisms, high organic loading, toxic metals, and pharmaceutical 
residues, which have detrimental effects on the environment (Majumder 
et al., 2021; Pariente et al., 2022; Wilkinson et al., 2022). The effluent 
discharged from different hospitals also contains high concentrations of 
ammonia, total nitrogen (TN), total suspended solids (TSS), and total 
dissolved solids (TDS) and is characterized by low biochemical oxygen 
demand/chemical oxygen demand ratio (BOD/COD ratios). HWW 
mainly comprises fecal matter and urine, which not only adds to the 
BOD of the wastewater but also contains pharmaceutically active com-
pounds (PhACs), which are the unmetabolized fraction of the pharma-
ceuticals administered to the patients. Most of these PhACs and their 
metabolites are extremely hydrophilic and have a complicated molec-
ular structure, preventing them from being degraded by traditional 
wastewater treatment methods (Roberts and Thomas, 2006; Teodosiu 
et al., 2018). In this context, advanced oxidation processes (AOPs) have 
been employed to degrade these PhACs (Oyewo et al., 2021; Pariente 
et al., 2022; Pastre et al., 2023). Although AOPs have been effective in 
degrading PhACs in synthetic wastewater prepared using deionized 
water, when treating real HWW, the organic matter and other inhibiting 
substances present in the HWW restrict the performance of the pro-
cesses. As a result, pre-treatment of the HWW is necessary. 
* Corresponding author. 
E-mail address: agupta@civil.iitkgp.ac.in (A.K. Gupta). 
Contents lists available at ScienceDirect 
Journal of Environmental Management 
journal homepage: www.elsevier.com/locate/jenvman 
https://doi.org/10.1016/j.jenvman.2023.119672 
Received 12 August 2023; Received in revised form 18 November 2023; Accepted 20 November 2023 
mailto:agupta@civil.iitkgp.ac.in
www.sciencedirect.com/science/journal/03014797
https://www.elsevier.com/locate/jenvman
https://doi.org/10.1016/j.jenvman.2023.119672
https://doi.org/10.1016/j.jenvman.2023.119672
https://doi.org/10.1016/j.jenvman.2023.119672
http://crossmark.crossref.org/dialog/?doi=10.1016/j.jenvman.2023.119672&domain=pdf
Journal of Environmental Management 351 (2024) 119672
2
In this context, this study focuses on the development of pilot-scale 
hybrid treatment technology comprising of advanced biological pro-
cesses and advanced oxidation process to treat hospital wastewater and 
emphasizing on the removal of a recalcitrant PhAC. The pilot-plant was 
constructed at Kharagpur Subdivisional Hospital, Kharagpur, India 
(22.32 ◦N, 87.31 ◦E) to treat the hospital wastewater generated directly 
from the hospital. The novelty of the work lies in the utilization of the 
pilot-scale treatment unit consisting of a combination of novel treatment 
technologies: a moving and stationary bed bioreactor-sedimentation 
tank (MBSST) and an aerated horizontal flow subsurface constructed 
wetland (AHFCW). Furthermore, a study on a combination of MBBR- 
based system, CW-based system and photocatalysis for treating waste-
water at pilot-scale has rarely been studied. 
The plant was operated at a capacity of 3000 L/day, and different 
treatment combinations were explored. The treatment combinations 
involved treatment of the HWW with MBSST, followed by AHFCW 
(continuous aeration), and photocatalysis in Phase 1. In phase 2, the 
HWW was only passed through AHFCW (continuous aeration) and then 
subjected to photocatalysis. Finally, in phase 3 of the operation, the 
AHFCW was provided intermittent aeration and the effluent was sub-
jected to photocatalysis. The HWW was spiked with carbamazepine 
(CBZ) since it is a neurotoxic drug and commonly detectable in waste-
water at concentrations ranging from 0.1 to 3 μg/L. Usually, CBZ can 
affect human beings directly at concentrations above 11 μg/L if exposed 
for a prolonged duration of time (Oliveira et al., 2015; Parida et al., 
2021; Verlicchi et al., 2012). Although the drinking water equivalent 
limit (DWEL) of carbamazepine (CBZ) is higher than the concentration 
found in hospital wastewater, prolonged exposure to lower levels of CBZ 
over time can still have harmful effects (Majumder et al., 2019a). 
Furthermore, CBZ has sublethal effects on organisms, such as disrup-
tions to reproductive, developmental, or behavioral processes, which 
can have significant ecological implications (Chen et al., 2019; Kohl 
et al., 2019; Vernouillet et al., 2010). Moreover, CBZ can bioaccumulate 
in organisms over time, which means that even though the concentra-
tion in the water is low, it can build up in the tissues of organisms as they 
are exposed continuously (Rodríguez-Mozaz et al., 2016; Valdés et al., 
2016; Vernouillet et al., 2010). This bioaccumulation can lead to higher 
concentrations in organisms higher up the food chain. Furthermore, it 
was found to be very difficult to degrade using biological systems as 
compared to other antibiotics (sulfamethoxazole) and 
endocrine-disrupting compoundsof the treatment units
	2.3 Phases of operation
	2.4 Sampling and analysis
	2.5 Toxicity evaluation methodology
	3 Results and discussion
	3.1 Biofilm characterization
	3.2 Performance of the pilot plant in phase 1
	3.3 Performance of the pilot plant in phases 2 and 3
	3.4 Photocatalytic treatment of the effluent of the pilot plant
	3.5 Degradation mechanism of carbamazepine in the different processes
	4 Conclusions
	Funding
	CRediT authorship contribution statement
	Declaration of competing interest
	Data availability
	Acknowledgements
	Appendix A Supplementary data
	References(17β estradiol) as observed in our 
previous study (Majumder et al., 2023). Additionally, it has also been 
reported that CBZ has very low biodegradability (Saidulu et al., 2021). 
Due to all these reasons, it is necessary to remove recalcitrant toxic 
compounds, such as CBZ at its source of generation and hence CBZ was 
chosen as the test compound. The treated effluent from the biological 
systems further underwent photocatalysis to remove any remaining 
CBZ. The intermediate products (IPs) formed, and their toxicity was 
assessed to comprehend the effectiveness of the treatment methodology. 
2. Materials and methods 
2.1. Location of the pilot-scale treatment unit and treatment units 
employed 
The pilot plant was set up at Kharagpur Subdivisional Hospital 
(22.32 ◦N, 87.31 ◦E). The wastewater generated from Kharagpur Sub-
divisional Hospital was discharged via open drains. The wastewater was 
collected from the open drains using gravity sewers and sent to the 
treatment site. The location of the plant, HWW generation and collection 
points and other details have been provided in Fig. 1. 
The schematic representation of the treatment system is shown in 
Fig. 2 (a) and the cross-sectional view of the AHFCW is shown in Fig. 2 
(b). The wastewater collected from the open drains is sent by gravity 
through sewer lines to a sump. The wastewater is pumped from the sump 
via a centrifugal pump and sent to the first stage of treatment. At the 
sump, CBZ dosing was carried out using a peristaltic pump to spike the 
concentration of the drug in the system and observe its removal. The 
CBZ dosing was carried out in such a way that the CBZ concentration in 
the wastewater reached to around 0.3 mg/L. The first stage of treatment 
Fig. 1. Location of pilot-scale treatment unit at Kharagpur Subdivisional, Kharagpur, India (22.32 ◦N, 87.31 ◦E). 
A. Majumder et al. 
Journal of Environmental Management 351 (2024) 119672
3
Fig. 2. (a) Schematic representation of the pilot-scale treatment system installed at Kharagpur Subdivisional Hospital and (b) cross-sectional view of the AHFCW. 
Fig. 3. (a) Schematic representation of (MBSST) with MBBR (left) and bio-tower (right), (b) SEM image of biofilm growth on the K2 bio carriers, (c) K2 bio carriers 
before and after the period of acclimatization, and (d) FTIR spectra of biofilm growth on the K2 bio carriers. 
A. Majumder et al. 
Journal of Environmental Management 351 (2024) 119672
4
comprises of a moving bed biofilm reactor (MBBR) (diameter = 0.8 m, 
height = 1.3 m) followed by a bio-tower (diameter = 0.9 m, height =
2.3 m) or super rate trickling filter comprising of a solid-liquid separator, 
which allows the bottom part of the bio-tower to act as a settling unit 
(Fig. 3). This setup has been collectively called the MBSST (Ghosal et al., 
2020). The schematic representation of the MBBR and the bio-tower 
(MBSST) is shown in Fig. 3(a). The side water depth in the MBBR tank 
is 1 m and has a freeboard of 0.3 m. In the bio-tower, the perforated slab, 
which is used as the solid-liquid separator, is provided at a height of 0.7 
m from the bottom of the tank. Above the perforated tank, a side water 
depth of 1.3 m is provided and a freeboard of 0.3 m. Both the MBBR tank 
and the bio-tower is filled with K2 bio-carriers (Fig. 3 (b and c). The 
bio-carriers were made of polypropylene and had a specific gravity of 
0.9, a specific surface area of 450 m2/m3, and a void ratio of 50 %. In the 
MBBR, the carrier fill was 22 %. The hydraulic retention time (HRT) 
provided for the MBBR tank was 4 h. The effluent of the MBBR then 
flows into the bio-tower by gravity, which is packed with the same K2 
bio-carriers used in the MBBR. As the water passes through the perfo-
rated screen, some of the suspended matter is settled inside the settling 
chamber, and the effluent flows by gravity into the AHFCW. 
The cross-sectional view of the AHFCW (Section A-A’ of Fig. 2 (a)) 
has been provided in Fig. 2 (b). The aeration setup of the AHFCW 
(length = 6 m, breadth = 2.33 m and height = 1 m) was carried out by 
placing drip lines along the length (diameter 16 mm and spacing of 11 
cm) and breadth (diameter 16 mm and spacing of 6 cm). The drip lines 
were connected to the diaphragm pump (JDK-S-100), having an optimal 
flow of 100 L/min. The wetland was then filled with siliceous gravel 
(8–16 mm) (Fig. S1 (a)). Larger gravels (30–50 mm) were placed at the 
inlet region and outlet region of the CW. The top layer of the constructed 
wetland (CW) was filled with coarse aggregates (Fig. S1 (b)). The 
AHFCW was planted with Canna indica. The effluent of the bio-tower 
was first collected in a small sump from where it flows by gravity into 
the AHFCW in the inlet zone, and the water trickles down and starts to 
flow towards the other end due to the slope proved (1/100). The flow 
was maintained at 3000 L/day, and the average porosity was 0.35. 
Hence, the HRT of the AHFCW was around 1.6 d. The step-by-step 
processes involved in the build-up of the AHFCW, including laying of 
drip lines, filling of the substrate material, plantation of macrophytes, 
and acclimatization, have been depicted in Fig. S1 (a-f). Once the 
AHFCW is filled, the water escapes from the outlet pipe in the outlet 
region and is collected in the sump. The effluent of the AHFCW was 
further treated with Al–ZnO/Fe in the presence of UV-A irradiation to 
remove any remaining traces of CBZ. 
2.2. Acclimatization of the treatment units 
The HWW was continuously fed through the pilot plant. In order to 
promote microbial growth, the MBBR, bio-tower, and AHFCW were 
inoculated with activated sludge, cow dung, and jaggery. The system 
was allowed to acclimatize for 2 months following which the steady 
state was achieved. After acclimatization, the formation of biofilm in the 
K2 bio carriers was evident as depicted in Fig. 3 (b) and (c). The Fourier 
transformed infrared radiations (FTIR) of the biofim formed on the K2 
carriers have been shown in Fig. 3 (d). 
In the AHFCW, the coarse aggregates below the top layer also turned 
brown, indicating the formation of biofilm (Fig. 4 (a)). The formation of 
algae was also observed on the top layer of the coarse aggregates, which 
were exposed to the sunlight (Fig. 4 (b)). The SEM image of the biofilm 
formed on the coarse aggregates has been depicted in Fig. 4 (c). The 
FTIR spectra of algae and biofilm have been shown in Fig. 4(d). Over a 
period of 30 d of acclimatization, the Canna indica also grew and became 
denser. The photograph of the complete pilot plant after the period of 
acclimatization is shown in Fig. 5. The various steps involved in the 
preparation and acclimatization of the AHFCW have been shown in 
Fig. S1. 
2.3. Phases of operation 
The pilot-scale treatment plant was operated in 3 phases. Each phase 
was carried out for a period of 15 d. The samples were collected and 
analyzed on a daily basis and the number of replicates for each sample 
was 3. In the first phase, the wastewater was allowed to pass through all 
Fig. 4. (a) Biofilm growth on coarse aggregates at 10 cm depth of AHFCW after the acclimatization period, (b) algal growth on the aggregates in the top layer of the 
AHFCW after the acclimatization period, (c) SEM images of biofilm growth on the coarse aggregates, and (d) FTIR spectra of biofilm grown on substrate at 10 cm 
depth of AHFCW, and algae grown on the coarse aggregates. 
A. Majumder et al.Journal of Environmental Management 351 (2024) 119672
5
the treatment units, i.e., the MBBR, bio-tower, and the AHFCW at a flow 
rate of 3000 L/day, and the plant was operated for 24 h a day. The 
aeration in the MBSST and the AHFCW was continuous. The perfor-
mance of each of the units was comprehended by analyzing the samples 
of the raw HWW, MBBR effluent, bio-tower effluent and AHFCW 
effluent. 
In the second phase, the HWW from the sump was directly diverted 
to the AHFCW. The MBBR and the bio-tower were bypassed to observe 
the efficiency of the AHFCW as a single biological treatment unit. The 
flow rate was kept the same, and aeration was provided for 24 h. In the 
third phase, the MBBR and the bio-tower were again bypassed and the 
performance of the AHFCW was assessed with intermittent aeration for 
6 h at 6 h intervals. The performance of each of the treatment units was 
assessed based on their ability to remove COD, TSS, turbidity and CBZ. 
Furthermore, the ammonia, nitrate, nitrite, TDS and pH at the end of 
each stage of treatment were also monitored. The characteristics of aw 
HWW characteristics and the effluent after each treatment unit in the 3 
different phases have been provided in Table 1. Photocatalysis using 
iron-modified aluminum-doped zinc oxide (Al–ZnO/Fe) was carried out 
after each of the treatment phases to check the removal of any remaining 
CBZ in the effluent of the AHFCW. 
Zinc Oxide (ZnO) was modified since it has a wide bandgap and has 
Fig. 5. Panoramic view of the pilot-plant at Kharagpur Subdivisional Hospital. 
Table 1 
Wastewater parameters before and after treatment. 
COD (mg/l) Turbiditity (NTU) TSS (mg/L) Carbamazepine (mg/L) TDS (mg/L) Ammonia (mg/L) Nitrite (mg/L) Nitrate (mg/L) 
Phase 1 
Raw HWW (Avg) 140.33 141.25 511.46 0.28 359.54 44.00 BDL 0.02 
Max 167 159 680 0.35 381 47.00 0.04 
Min 105 103 289 0.27 324 41.00 0.01 
S.D 32.63 15.56 103.23 0.03 16.30 2.16 0.02 
Post MBBR (Avg) 91.33 24.97 66.85 0.23 316.85 13.00 BDL 0.90 
Max 124 33.3 89 0.31 336 15.00 1.20 
Min 42 16.5 39 0.17 283 10.00 0.60 
S.D 32.42 5.80 15.63 0.05 15.99 1.72 0.30 
Post MBSST (Avg) 52.03 14.18 89 0.19 285.92 11.00 BDL 0.07 
Max 93 22.6 56 0.21 354 14.00 0.09 
Min 33.2 6.64 29 0.16 213 9.00 0.04 
S.D 25.72 5.24 7.70 0.02 38.34 1.94 0.02 
Post AHFCW(Avg) 19.66 8.46 34.46 0.20 251.69 0.12 BDL 0.05 
Max 33 16.2 78 0.21 283 0.17 0.07 
Min 4.15 4.71 22 0.17 220 0.03 0.02 
S.D 11.42 3.81 14.85 0.01 18.75 0.06 0.02 
Phase 2 
Raw HWW (Avg) 132.86 125.86 542.29 0.32 259.86 40.00 0.06 5.30 
Max 156.00 144.00 623.00 0.33 287.00 45.00 0.08 7.80 
Min 115.00 110.00 445.00 0.30 220.00 37.00 0.04 3.40 
S.D 14.03 11.22 61.75 0.02 22.94 3.21 0.02 1.81 
Post AHFCW (Avg) 37.16 40.57 121.57 0.21 233.57 0.67 0.55 45.00 
Max 52.00 45.00 167.00 0.21 252.00 1.20 0.60 48.00 
Min 24.00 31.00 89.00 0.14 209.00 0.30 0.50 41.00 
S.D 9.98 4.72 23.82 0.03 16.27 0.33 0.05 3.27 
Phase 3 
Raw HWW (Avg) 125.50 118.67 579.00 0.35 252.33 52.12 0.05 5.19 
Max 154.00 129.00 789.00 0.38 289.00 45 0.10 5.60 
Min 105.00 109.00 453.00 0.34 213.00 55 0.02 4.70 
S.D 23.31 8.31 128.17 0.02 25.48 56 0.03 0.36 
Post AHFCW (Avg) 53.67 39.71 114.86 0.26 226.17 4.78 1.43 15.16 
Max 66.00 48.00 189.00 0.27 246.00 2.8 1.53 18.10 
Min 46.00 32.00 78.00 0.26 211.00 6.2 1.33 12.20 
S.D 7.84 6.74 38.94 0.01 12.98 5.3 0.08 2.52 
Avg: Average, SD: Standard deviation, BDL: Below Detection Limit. 
A. Majumder et al. 
Journal of Environmental Management 351 (2024) 119672
6
exhibited promising photocatalytic activity as per the literature (Abebe 
et al., 2020; Majumder and Gupta, 2020, 2021; Priyanka and Srivastava, 
2013). However, electron-hole recombination is a significant downside 
of photocatalysis using ZnO. To prevent the recombination of electrons 
and holes, Al doping was carried out (Majumder et al., 2022). Further, in 
order to facilitate easy separation from the aqueous medium or from the 
bottom of the reactor, Fe modification was carried out to induce mag-
netic properties to the photocatalyst. The optimum synthesis conditions 
for the Al–ZnO/Fe photocatalyst have been described elsewhere 
(Majumder et al., 2022). The continuous photocatalytic reactor used in 
this study is shown in Fig. S2. It consists of two chambers with di-
mensions of 0.5 m in length, 0.1 m in breadth, and 0.7 m in height. Three 
of these chamber’s surfaces are non-transparent and coated with white 
material to enhance light scattering while preventing light from 
escaping. The first chamber serves as the photocatalysis chamber, where 
contaminated water is introduced into the system. The second chamber 
functions as a settling chamber for the photocatalyst particles. Between 
these two chambers, a UV setup is installed, capable of accommodating 
up to three 15 W UV-A lamps (Majumder et al., 2023). Additionally, an 
overhead 15 W UV-A lamp is positioned above the photocatalysis 
chamber (Fig. S2). As contaminated water enters the photocatalytic 
chamber, it undergoes stirring via an overhead stirrer, and aeration is 
provided from the bottom. This stirring and aeration assist in main-
taining the suspension of the photocatalyst material. Once the water 
level reaches a specified point based on the designated hydraulic 
retention time (HRT), the water is directed through connecting pipes 
into the photocatalyst settling chamber. In this chamber, the photo-
catalyst settles, allowing the clear supernatant to exit through the outlet 
(Fig. S2). The photocatalytic studies of the effluent of the AHFCW were 
carried out by subjecting the effluent to UV-A irradiation. The effluent 
flow was maintained at around 8.33 L/h, and the Al–ZnO/Fe dose was 
maintained at 0.5 g/L in the photocatalytic chamber. Overall, an HRT of 
3 h was provided. The operating conditions used in this study were 
optimized elsewhere (Majumder et al., 2023). 
2.4. Sampling and analysis 
The raw HWW sample was collected from the influent drain. The 
second sampling point was after the MBBR unit, the third sampling point 
was from the effluent pipe of the bio-tower and the final sampling point 
was the effluent pipe of the AHFCW. The photocatalytic treated sample 
was collected after the sedimentation tank in the photocatalytic reactor 
(Fig. S2)). The physical and chemical parameters of wastewater, such as 
TSS and COD, were measured according to standard methods (APHA, 
2017). Turbidity was measured using a 2100Q Portable Turbidimeter. 
TDS and pH were measured using Multi-Parameter Tester 35 (Thermo 
Scientific) and pH/ORP analyzer (Analab), respectively. Ammonia, ni-
trate, and nitrite were measured using a photometer (MD 600 (Lovi-
bond)). The wastewater samples were collected and stored in ice boxes 
and carried to the laboratory for further analysis. The samples were 
filtered using 0.22-μm filter paper and stored at − 20 ◦C before carrying 
out the chromatographic analysis. CBZ quantification was carried out 
using high-performance liquid chromatography (HPLC) (Thermo Fisher 
Scientific, Ultimate 3000). Deionized water (DI) and HPLC-grade 
acetonitrile in the ratio of 1:1 was used as the mobile phase, while the 
stationary phase was a C18 column. The CBZ was detected at a wave-
length of 281 nm. The limit of detection for CBZ using HPLC was 20 
μg/L. 
To identify the intermediates of CBZ, LC-MS analysis was conducted 
using a Waters 2695 separation module connected to a QuattroMicroTM 
API mass spectrometer (Waters, USA). Data acquisition and processing 
were carried out using Waters Mass Lynx 4.1 software. Samples (10 μL) 
were introduced into the LC system by an auto-sampler and separated on 
an XTerra MS C18 reversed-phase column (2.1 mm internal diameter, 
100 mm length, 2.5 m particle size). The mobile phase was composedof 
a 50% acetonitrile and 50% deionized water mixture, with a flow rate of 
0.5 mL/min and a column temperature of 25 ◦C. The LC-eluted samples 
were passed through the negative electrospray ionization (ESI (− )) 
source. The data were collected in the MS scanning mode, covering a 
mass/charge ratio (m/z) scan range of 100–500. Solid-phase extraction 
followed by LC-MS was used to identify other PhACs present in the raw 
HWW. The concentration of the detected PhACs in the raw wastewater 
before spinking with CBZ has been shown in Table S1. 
2.5. Toxicity evaluation methodology 
The intermediate or transformation products (IPs) formed during the 
degradation of the target PhAC, CBZ, were identified using LC-MS. The 
toxicity evaluation of CBZ and its IPs generated during degradation was 
conducted using the Toxicity Estimation Software Tool (T.E.S.T). 
Recently, various studies have reported the use of The Toxicity Esti-
mation Software Tool (T.E.S.T) to find out the toxicity of various com-
pounds formed during treatment (Cai et al., 2023; Jain et al., 2023; Li 
et al., 2023). In this context, T.E.S.T was used to evaluate the Devel-
opmental toxicity, Fathead minnow LC50 (96 h) (mg/L), and Daphnia 
magna LC50 (48 h) (mg/L) for the parent compound (CBZ) and the IPs to 
evaluate their toxicity. T.E.S.T operates by utilizing chemical structures 
to predict the toxicity of compounds. It employs quantitative 
structure-activity relationship (QSAR) models and toxicity data to esti-
mate parameters such as ecotoxicity, mutagenicity, and carcinogenicity. 
These estimates are then used to predict the potential toxicity of a given 
compound, aiding in risk assessment and decision-making. 
3. Results and discussion 
3.1. Biofilm characterization 
The SEM image of the formed biofilm layer is shown in Fig. 3 (c). The 
figure depicts the formation of a thin layer of biofilm formed on the 
surface of the K2 carriers. The SEM image of the biofilm formed on the 
coarse aggregates has been depicted in Fig. 4 (c). Similar formations of 
biofilm on the surface of aggregates were observed in other studies 
(Mingchao et al., 2013; Srivastava et al., 2020; Yan et al., 2018). The 
FTIR spectra of the biofilm obtained from the K2 bio-carriers is shown in 
Fig. 3(d), and algae grown on the coarse aggregates and biofilm devel-
oped on the surface of coarse aggregates have been depicted in Fig. 4 (d), 
respectively. The peak at around 1020 cm− 1 may be indicative of pol-
yphosphate species, which is a primary component of activated sludge 
(Shen et al., 2018; Staal et al., 2019). The peak was the strongest on the 
coarse aggregates in the CW substrate. The peak at around 780 cm− 1 
may be assigned to thymine, cytosine, or uracil, which is common in 
biofilm samples (Wickramasinghe et al., 2020). The peak at 780 cm− 1 
was only prominent in the algae and biofilm of the CW substrate. The 
peaks at around 1540 cm− 1 and 1640 cm− 1 may be attributed to amide II 
and amide I resulting from the formation of biofilm (Hu et al., 2013). 
The peaks at 2845 cm− 1 and 2924 cm− 1 may be attributed to C–H 
out-of-plane bending, symmetric and non-symmetric stretching bond 
with carbonyl, respectively (Mohan et al., 1991; Trovati et al., 2010). 
The wide peak ranging from 3100 cm− 1 to 3600 cm− 1 is due to the OH 
group arising from the absorbed water molecules (Jain et al., 2023; 
Majumder et al., 2019b). The FTIR analysis confirms the formation of 
biofilm on the surface of K2 biocarriers and coarse aggregates and also 
deepens our understanding of the diverse components within the sam-
ples, offering a foundation for further environmental investigations. 
These findings help us to associate the removal of organics in the bio-
logical systems with microbial growth. 
3.2. Performance of the pilot plant in phase 1 
The concentration and removal of COD, turbidity, TSS, CBZ, TDS, 
and pH at different stages of phase 1 of treatment have been provided in 
Fig. 6(a–f), respectively. In phase 1, the raw HWW from the sump 
A. Majumder et al. 
Journal of Environmental Management 351 (2024) 119672
7
entered the MBBR unit. In the MBBR unit, the average removal of COD 
and CBZ was 36.41 ± 12.25% and 21.03 ± 9.89%, respectively. The 
COD acted as the food for the microorganisms, and aerobic degradation 
took place in the presence of continuous aeration. Post MBBR, there was 
a drop in TSS and turbidity. The TSS and turbidity in the effluent of the 
MBBR were 66.15 ± 15.6 mg/L and 24.96 ± 5.79 NTU, respectively. 
The TSS in the effluent of the MBBR was primarily the mixed liquor 
suspended solids (MLSS). The drop in TSS and turbidity may be attrib-
uted to the settling of suspended matter that occurred in the sump from 
where the wastewater was pumped. There was very little removal of CBZ 
observed in the MBBR unit. Similar low removal of CBZ has been 
observed in other biological processes as well (Dubey et al., 2023; Sai-
dulu et al., 2021). This is primarily because CBZ has a complex molec-
ular structure and is not easily degraded by biological processes. The low 
biodegradability of CBZ is marked by a very low biomass normalized 
rate constant (Saidulu et al., 2021). Furthermore, CBZ is not highly 
hydrophobic; thereby, it also does not get adsorbed onto the biomass in 
the system. Similar low removal for CBZ was observed in MBBR by other 
researchers (Casas et al., 2015; Luo et al., 2015). The pH of MBBR 
effluent was around 7.55, and the TDS was around 316.85 ± 15.99 
mg/L. The pH of the MBBR effluent was slightly increased from around 
7.3 in the raw wastewater. This may be due to the aeration, which 
caused turbulence in the system and led to the outgassing of CO2 from 
the water, resulting in an increase in pH (Sundberg and Jönsson, 2008). 
Following the MBBR, the wastewater was passed through the bio- 
tower. The total COD removal achieved at the end of the bio-tower 
was 63.64 ± 12.99%. The TSS and turbidity concentration were 
further reduced due to the presence of the settling tank at the bottom of 
the bio-tower. The TSS and turbidity in the effluent of MBSST were 
found to be 40.23 ± 7.70 mg/L and 14.17 ± 5.23 NTU, respectively. 
Although the COD removal was high, there was no significant 
improvement in the CBZ removal as the total COD removal post-MBSST 
was 30.94 ± 9.90%. The pH of MBBR effluent was around 7.56, and the 
TDS was around 285.92 ± 38.34 mg/L. 
Fig. 6. Removal of (a) COD, (b) turbidity, (c) TSS, (d) CBZ, (e) TDS, and (f) pH in raw hospital wastewater, MBBR effluent, MBSST effluent, and AHFCW effluent 
during the pilot scale operation (Phase 1, 2, and 3). 
A. Majumder et al. 
Journal of Environmental Management 351 (2024) 119672
8
The wastewater was passed through the AHFCW following the 
MBSST. The COD removal after the AHFCW was 85.25 ± 9.75%. The 
turbidity (8.46 ± 3.81 NTU) and the TSS (34.46 ± 14.84 mg/L) of the 
effluent were also greatly reduced. This is because several removal 
mechanisms, such as adsorption, filtration, microbial degradation, and 
plant uptake, occur in the wetlands (Varma et al., 2021). The aeration of 
the system further helped to remove the contaminants and prevented the 
formation of sludge cake at the bottom of the wetland, which might have 
led to the clogging of the system and the formation of anoxic conditions. 
However, there was no significant removal of CBZ observed. Similar to 
MBBR, there was an increase in pH due to the aeration leading to the 
degassing of CO2 (Sundberg and Jönsson, 2008). The TDS in the effluent 
of theAHFCW was found to be 251.69 ± 18.75 mg/L. In phase 1, a TDS 
reduction of 29.91 ± 5.65% could be achieved. 
The average ammonia concentration in the raw HWW was around 
44 mg/L. After the MBSST, the average ammonia concentration was 
around 11 mg/L. Ammonia removal of around 75% indicates that the 
system is capable of nitrification. The C/N ratio in the system was 
around 2.77. The low C/N ratio favored the nitrification process. The 
average ammonia concentration was further reduced to around 0.15 
mg/L after the AHFCW. During acclimatization, the autotrophs devel-
oped well in the MBBR, bio-tower, and AHFCW. This allowed efficient 
ammonia removal. It was reported that around 70–90% ammonia 
removal could be achieved in a low C/N ratio of 3.5 to 2 (Sharma and 
Gupta, 2004). It was also reported that a low C/N ratio improves the 
ammonia removal performance due to the predominance of 
ammonia-oxidizing bacteria and nitrite-oxidizing bacteria, causing 
efficient nitrification under appropriate DO concentration (Yadu et al., 
2018). 
3.3. Performance of the pilot plant in phases 2 and 3 
The concentration and removal of COD, turbidity, TSS, CBZ, TDS, 
and pH at different stages of phases 2 and 3 of treatment have been 
provided in Fig. 6(a–f), respectively. In Phase 2 of the treatment, the 
MBSST was bypassed, and the HWW was directly sent to the AHFCW. In 
Phase 2, continuous aeration was provided, while in phase 3, intermit-
tent aeration was provided to minimize the operation cost. The COD, 
TSS, turbidity, CBZ, and TDS removal of around 72%, 68%, 78%, 35%, 
and 10% could be achieved in Phase 2. Microbial degradation, adsorp-
tion, and filtration could be the major treatment mechanisms involved in 
the AHFCW. The pH of the wastewater also increased from 7.73 to 8.03 
due to the degassing of CO2 caused due to continuous aeration. The 
average concentration of ammonia was around 40 mg/L. The average 
ammonia concentration in the effluent of the AHFCW was found to be 
0.67 mg/L. High removal of ammonia (~98.4%) was obtained in the 
AHFCW system alone. The nitrifying bacteria converted the ammonia to 
nitrate. As a result, the nitrate content of the wastewater increased from 
around 5.3 mg/L in the raw HWW to around 45 mg/L in the AHFCW 
effluent (Ambulkar, 2017; Kamilya et al., 2022; Zhou et al., 2019). Since 
the AHFCW was completely aerated, most of the ammonia got converted 
to nitrite and then nitrate. The nitrite concentration in the raw HWW 
and AHFCW effluent was around 0.06 mg/L and 0.55 mg/L, respec-
tively. This indicates that nitrification had occurred in the system under 
oxic conditions (Saidulu et al., 2023). 
In phase 3, aeration was provided for 6 h and then stopped for 6 h. 
This might lead to the formation of temporary anoxic conditions in the 
lower portion of the AHFCW. Hence, some anaerobic degradation might 
also have taken place, which lead to the formation of organic acids via 
acidogenesis and acetogenesis (Tchobanoglous et al., 2014). This might 
be accounted for the lowering in pH of the wastewater from 7.42 to 7.17. 
Anoxic conditions in a constructed wetland can lead to a decrease in pH 
due to the processes of acidogenesis and acetogenesis. When organic 
matter accumulates and undergoes decomposition in the absence of 
oxygen, acidogenic bacteria break down complex organic compounds 
into simpler organic acids, and acetogenic bacteria further metabolize 
these acids into acetate. These metabolic processes can release acidic 
compounds, which, in turn, lower the pH of the wetland’s water (Gupta 
et al., 2023; Tchobanoglous et al., 2014). Similar observations were 
reported in other studies as well (Setiawan and Hardiani, 2020; Tang 
et al., 2020). However, due to intermittent aeration, the aerobic 
degradation was hindered, and that affected the COD removal. The COD 
content of the wastewater was brought down from 125.50 ± 23.31 mg/L 
to 53.67 ± 7.84 mg/L (~57% removal). The TSS, turbidity, CBZ, and 
TDS removal of around 80%, 67%, 26%, and 10%, respectively, was 
achieved. The TSS and turbidity removal were not significantly affected. 
However, the CBZ removal was further reduced in the absence of 
continuous aeration. Intermittent aeration allowed the formation of 
aerobic and anoxic conditions in the AHFCW. The HRT of the wetland 
was around 1.6 d. It meant the wastewater received around 3 cycles of 6 
h or aerated and 6 h of non-aerated period. As a result, the system 
facilitated simultaneous nitrification and denitrification during this 
period. The C/N ratio during this period was around 2.7. The average 
ammonia concentration in the raw HWW was around 52.15 mg/L. The 
ammonia removal obtained during this period was around 91%, as the 
average ammonia concentration in the AHFCW effluent was 4.78 mg/L. 
The average nitrate concentration in the raw HWW and AHFCW effluent 
was around 5.19 mg/L and 15.16 mg/L. The increase in nitrate con-
centration was not as high as observed in phase 2. The average nitrite 
concentration in the effluent was also around 1.43 mg/L. This is because 
the denitrification of nitrate to N2 took place during the anoxic period in 
phase 3 (Tchobanoglous et al., 2014). 
3.4. Photocatalytic treatment of the effluent of the pilot plant 
In an earlier study (Majumder et al., 2023), it was observed that 
when photocatalysis was used alone, the CBZ removal was around 10% 
in real hospital wastewater as compared to 85% in deionized water. 
However, when a constructed wetland was used as a pre-treatment, CBZ 
removal increased to more than 90% (Majumder et al., 2023). When 
photocatalysis was applied directly to hospital wastewater, the rapid 
degradation of easily degradable organic matter led to premature 
exhaustion of photocatalysts. Moreover, the presence of suspended 
solids obstructed active sites on the photocatalysts and also made the 
solution turbid, thereby limiting light transmission. Furthermore, 
interfering ions consume oxidizing radicals, hindering the degradation 
of recalcitrant CBZ (Azrague et al., 2007; Majumder et al., 2023). In 
order to address these challenges and adopt a holistic approach, a 
pre-treatment step using MBSST and AHFCW was implemented in this 
study. The concentration of the CBZ in the effluent of the pilot plant 
(Phase 1 to 3) and the final concentration of CBZ after photocatalytic 
Fig. 7. Performance of photocatalysis in the removal of CBZ from the effluent 
of the pilot plant. 
A. Majumder et al. 
Journal of Environmental Management 351 (2024) 119672
9
treatment, along with the removal efficiency, have been depicted in 
Fig. 7. The final CBZ concentration after the photocatalytic treatment 
was found to be 22 ± 3.83 μg/L, 34 ± 20 μg/L, and 37 ± 20 μg/L for the 
effluent from phase 1, phase 2, and phase 3, respectively. The obtained 
CBZ removal efficiency was noted as 88 ± 2%, 83 ± 2.5%, and 85 ±
1.5% for the effluent of phase 1, phase 2, and phase 3, respectively. The 
slightly higher CBZ removal for the effluent of phase 1 may be because 
the final TSS and organic content of the effluent was lower than that of 
phases 2 and 3. As a result, the interference was also minimal for the 
effluent of phase 1. The primary radicals responsible for CBZ degrada-
tion are superoxide (O2
•-) and hydroxyl (OH•) radicals (Majumder et al., 
2022). These radicals tend to get scavenged in the presence of suspended 
solids and organic matter. Furthermore, the organic matter, which is 
more hydrophobic than CBZ, competes with CBZ and gets preferentially 
degraded, resulting in lower CBZ removal (Ye et al., 2018). It was 
observed that the concentration of the compounds in the raw hospital 
wastewater was very low (quantify and hence, in this study, their effect on 
CBZ degradation could not be accounted. However, in an earlier study, 
the CBZ removal from deionized water using the same photocatalytic 
reactor was carried out. At similar operation conditions and an HRT of 3 
h, around 85% CBZ removal was observed (Majumder et al., 2023). In 
this study, the CBZ removal from the effluent of AHFCW using photo-
catalytic reactor was found to vary between 83% and 88%. Hence, other 
PhACs and their degradation products may not have significantly 
affected the removal of CBZ in the photocatalytic reactor. The results 
also suggested pre-treatment effectively reduced the levels of easily 
degradable organic matter, suspended solids, and interfering agents in 
hospital wastewater. This pre-treatment paved the way for enhanced 
CBZ removal during subsequent photocatalysis, with the CBZ removal 
efficiency reaching more than 85%. The integrated approach not only 
targeted CBZ but also addressed the overall composition of hospital 
wastewater. 
3.5. Degradation mechanism of carbamazepine in the different processes 
The IPs obtained from LC-MS analysis of the MBSST effluent, AHFCW 
effluent and after photocatalysis are shown in Table 2. Table 2 also 
depicts the toxicity of the products formed. In the MBSST and the 
AHFCW, the CBZ molecules underwent subsequent hydroxylation, 
deamination, and bond breakage to form IP2 via various enzymatic re-
actions (Alur, 1999; Li et al., 2013; Moreira et al., 2018). IP2 underwent 
further ring contraction to get converted to IP3, which underwent bond 
cleavage to form IP4 (Li et al., 2013). Further bond cleavage might have 
led to the formation of IP6, which underwent hydroxylation (IP7) in the 
MBSST to form hydroquinone (Moreira et al., 2018) or carboxylation 
(Megonigal et al., 2003) in the AHFCW to form benzoic acid (IP8). 
Similar results were found in our earlier study (Majumder et al., 2023). 
Iminostilbene (IP9) may also be formed by subsequent deamination and 
bond breakage of the CBZ molecule (Alur, 1999). During photocatalysis, 
the CBZ molecule is likely to get attacked by the formed hydroxyl rad-
icals (OH•) to form IP10. IP10 may undergo further bond breakage, 
hydroxylation, and oxidation to form IP11, which may undergo ring 
cleavage to form 1P12 (Majumder et al., 2022). IP12 may undergo 
deamination to form IP8, and IP4 (in the effluent of AHFCW) may un-
dergo ring cleavage to form IP5. The degradation pathway has been 
depicted in Fig. 8. It was observed that the IPs formed during the 
biodegradation in MBSST and AHFCW had significant toxicity (Table 2). 
Furthermore, a significant portion of the CBZ was not removed in these 
two processes. However, during photocatalysis, substantial degradation 
of CBZ and the IPs formed showed much lower toxicity than the parent 
compound and the other IPs. As per Fig. 8, IP-5 and IP-8 are the IPs 
formed after photocatalysis. IP-5 and IP-8 were observed in the effluent 
of the photocatalytic reactor as well. The LC50 values of IP-8 were 
significantly high, and that of IP-5 was also found to be higher than that 
of CBZ. This indicates that the IPs had a much lower toxicity as 
compared to the parent compound. Furthermore, since these are IPs of 
Table 2 
Intermediate products of carbamazepine formed during the pilot-scale treatment and their toxicity. 
A. Majumder et al. 
Journal of Environmental Management 351 (2024) 119672
10
the parent compound, their concentrations were very low (Conceptualization, Methodology, Writing - review & editing, 
Visualization. 
Declaration of competing interest 
The authors declare that they have no known competing financial 
interests or personal relationships that could have appeared to influence 
the work reported in this paper. 
Data availability 
Data will be made available on request. 
Acknowledgements 
The authors are grateful for the help received from the School of 
Environmental Science and Engineering, Indian Institute of Technology 
Kharagpur and Central Research Facility, Indian Institute of Technology 
Kharagpur, for providing laboratory facilities. 
Appendix A. Supplementary data 
Supplementary data to this article can be found online at https://doi. 
org/10.1016/j.jenvman.2023.119672. 
References 
Abebe, B., Murthy, H.C.A., Amare, E., 2020. Enhancing the photocatalytic efficiency of 
ZnO: defects, heterojunction, and optimization. Environ. Nanotechnol. Monit. 
Manag. https://doi.org/10.1016/j.enmm.2020.100336. 
Alur, M.D., 1999. METABOLIC PATHWAYS | Nitrogen Metabolism. Elsevier, Oxford. 
https://doi.org/10.1006/rwfm.1999.1005. 
Ambulkar, A.R., 2017. Nutrient pollution and wastewater treatment systems. In: Oxford 
Research Encyclopedia of Environmental Science. https://doi.org/10.1093/ 
acrefore/9780199389414.013.495. 
APHA, 2017. Standard Methods for the Examination of Water and Wastewater Standard 
Methods for the Examination of Water and Wastewater. American Public Health 
Association. https://doi.org/10.1016/0043-1354(82)90249-4. 
Azrague, K., Aimar, P., Benoit-Marquié, F., Maurette, M.T., 2007. A new combination of 
a membrane and a photocatalytic reactor for the depollution of turbid water. Appl. 
Catal. B Environ. 72, 197–204. 
Cai, M., Liu, Y., Wang, C., Lin, W., Li, S., 2023. Novel Cd0.5Zn0.5S/Bi2MoO6 S-scheme 
heterojunction for boosting the photodegradation of antibiotic enrofloxacin: 
degradation pathway, mechanism and toxicity assessment. Sep. Purif. Technol. 304, 
122401 https://doi.org/10.1016/j.seppur.2022.122401. 
Casas, M.E., Chhetri, R.K., Ooi, G., Hansen, K.M.S., Litty, K., Christensson, M., 
Kragelund, C., Andersen, H.R., Bester, K., 2015. Biodegradation of pharmaceuticals 
in hospital wastewater by staged moving bed biofilm reactors (MBBR). Water Res. 
83, 293–302. https://doi.org/10.1016/j.watres.2015.06.042. 
Chen, H., Gu, X., Zeng, Q., Mao, Z., 2019. Acute and chronic toxicity of carbamazepine 
on the release of chitobiase, molting, and reproduction in Daphnia similis. Int. J. 
Environ. Res. Publ. Health 16, 209. 
Dubey, M., Vellanki, B.P., Kazmi, A.A., 2023. Fate of emerging contaminants in a 
sequencing batch reactor and potential of biological activated carbon as tertiary 
treatment for the removal of persisting contaminants. J. Environ. Manag. 338, 
117802 https://doi.org/10.1016/j.jenvman.2023.117802. 
Ghosal, P.S., Gupta, A.K., Gupta, B., Lal, S., 2020. An Improved Secondary Treatment 
Unit of Wastewater Comprising of Moving and Stationary Bed Bio-Reactor- 
Sedimentation Tank (MBSST). Indian Patent Office. Google Patents (Patent No. 
202031010688). 
Gupta, A.K., Uddameri, V., Majumder, A., Nimbhorkar, S.K., 2023. Wastewater 
Engineering: Issues, Trends, and Solutions. CRC Press. 
Hu, X.B., Xu, K., Wang, Z., Ding, L.L., Ren, H.Q., 2013. Characteristics of biofilm 
attaching to carriers in moving bed biofilm reactor used to treat vitamin C 
wastewater. Scanning 35. https://doi.org/10.1002/sca.21064. 
Jain, M., Sai Kiran, P., Ghosal, P.S., Gupta, A.K., 2023. Development of microbial fuel cell 
integrated constructed wetland (CMFC) for removal of paracetamol and diclofenac 
in hospital wastewater. J. Environ. Manag. 344, 118686 https://doi.org/10.1016/j. 
jenvman.2023.118686. 
Kamilya, T., Majumder, A., Yadav, M.K., Ayoob, S., Tripathy, S., Gupta, A.K., 2022. 
Nutrient pollution and its remediation using constructed wetlands: insights into 
removal and recovery mechanisms, modifications and sustainable aspects. 
J. Environ. Chem. Eng. 10, 107444 https://doi.org/10.1016/J.JECE.2022.107444. 
Kohl, A., Golan, N., Cinnamon, Y., Genin, O., Chefetz, B., Sela-Donenfeld, D., 2019. 
A proof of concept study demonstrating that environmental levels of carbamazepine 
impair early stages of chick embryonic development. Environ. Int. 129, 583–594. 
https://doi.org/10.1016/j.envint.2019.03.064. 
Li, J., Dodgen, L., Ye, Q., Gan, J., 2013. Degradation kinetics and metabolites of 
carbamazepine in soil. Environ. Sci. Technol. 47, 3678–3684. https://doi.org/ 
10.1021/es304944c. 
Li, S., Wang, C., Liu, Yanping, Liu, Yazi, Cai, M., Zhao, W., Duan, X., 2023. S-scheme MIL- 
101 (Fe) octahedrons modified Bi2WO6 microspheres for photocatalytic 
decontamination of Cr (VI) and tetracycline hydrochloride: synergistic insights, 
reaction pathways, and toxicity analysis. Chem. Eng. J. 455, 140943. 
Luo, Y., Jiang, Q., Ngo, H.H., Nghiem, L.D., Hai, F.I., Price, W.E., Wang, J., Guo, W., 
2015. Evaluation of micropollutant removal and fouling reduction in a hybrid 
moving bed biofilm reactor-membrane bioreactor system. Bioresour. Technol. 191, 
355–359. https://doi.org/10.1016/j.biortech.2015.05.073. 
Majumder, A., Bhatnagar, A., Kumar Gupta, A., 2023. Simultaneous removal of 
sulfamethoxazole, 17β-estradiol, and carbamazepine from hospital wastewater using 
a combination of a continuous constructed wetland-based system followed by 
photocatalytic reactor. Chem. Eng. J. 143255 https://doi.org/10.1016/j. 
cej.2023.143255. 
Majumder, A., Gupta, A.K., 2021. Kinetic modeling of the photocatalytic degradation of 
17-β estradiol using polythiophene modified Al-doped ZnO: influence of operating 
parameters, interfering ions, and estimation of the degradation pathways. 
J. Environ. Chem. Eng. 9, 106496 https://doi.org/10.1016/J.JECE.2021.106496. 
Majumder, A., Gupta, A.K., 2020. Enhanced photocatalytic degradation of 17β-estradiol 
by polythiophene modified Al-doped ZnO: optimization of synthesis parameters 
using multivariate optimization techniques. J. Environ. Chem. Eng. 8, 104463 
https://doi.org/10.1016/j.jece.2020.104463. 
Majumder, A., Gupta, A.K., Ghosal, P.S., Varma, M., 2021. A review on hospital 
wastewater treatment: a special emphasis on occurrence and removal of 
pharmaceutically active compounds, resistant microorganisms, and SARS-CoV-2. 
J. Environ. Chem. Eng. 9, 104812 https://doi.org/10.1016/j.jece.2020.104812. 
Majumder, A., Gupta, A.K., Sillanpää, M., 2022. Insights into kinetics of photocatalytic 
degradation of neurotoxic carbamazepine using magnetically separable mesoporous 
Fe3O4 modified Al-doped ZnO: delineating the degradation pathway, toxicity 
analysis and application in real hospital wastewater. Colloids Surfaces A 
Physicochem. Eng. Asp. 648 https://doi.org/10.1016/j.colsurfa.2022.129250. 
Majumder, A., Gupta, B., Gupta, A.K., 2019a. Pharmaceutically active compounds in 
aqueous environment: a status, toxicity and insights of remediation. Environ. Res. 
176, 108542 https://doi.org/10.1016/j.envres.2019.108542. 
Majumder, A., Ramrakhiani, L., Mukherjee, D., Mishra, U., Halder, A., Mandal, A.K., 
Ghosh, S., 2019b. Green synthesis of iron oxide nanoparticles for arsenic 
remediation in water and sludge utilization. Clean Technol. Environ. Policy 21, 
1–19. https://doi.org/10.1007/s10098-019-01669-1. 
Megonigal, J.P., Hines, M.E., Visscher, P.T., 2003. In: Holland, H.D., Turekian, K.K., B.T.- 
T. on G (Eds.), 8.08 - Anaerobic Metabolism: Linkages to Trace Gases and Aerobic 
Processes. Pergamon, Oxford, pp. 317–424. https://doi.org/10.1016/B0-08-043751- 
6/08132-9. 
Mingchao, L., Tianzhi, W., Yunkai, L., Peiling, Y., Chengcheng, L., Pengxiang, L., Wei, Z., 
2013. Structural and fractal characteristics of biofilm attached on the surfaces of 
aquatic plants and gravels in the rivers and lakes reusing reclaimed wastewater. 
Environ. Earth Sci. 70, 2319–2333. https://doi.org/10.1007/s12665-013-2285-3. 
Mohan, S., Sundaraganesan, N., Mink, J., 1991. FTIR and Raman studies on 
benzimidazole.Spectrochim. Acta Part A Mol. Spectrosc. 47 https://doi.org/ 
10.1016/0584-8539(91)80042-H. 
Moreira, I.S., Bessa, V.S., Murgolo, S., Piccirillo, C., Mascolo, G., Castro, P.M.L., 2018. 
Biodegradation of Diclofenac by the bacterial strain Labrys portucalensis F11. 
Ecotoxicol. Environ. Saf. 152, 104–113. https://doi.org/10.1016/j. 
ecoenv.2018.01.040. 
Oliveira, T.S., Murphy, M., Mendola, N., Wong, V., Carlson, D., Waring, L., 2015. 
Characterization of Pharmaceuticals and Personal Care products in hospital effluent 
and waste water influent/effluent by direct-injection LC-MS-MS. Sci. Total Environ. 
518–519, 459–478. https://doi.org/10.1016/J.SCITOTENV.2015.02.104. 
Oyewo, O.A., Nevondo, N.G., Onwudiwe, D.C., Onyango, M.S., 2021. Photocatalytic 
degradation of methyl blue in water using sawdust-derived cellulose nanocrystals- 
metal oxide nanocomposite. J. Inorg. Organomet. Polym. Mater. 31 https://doi.org/ 
10.1007/s10904-020-01847-5. 
Parida, V.K., Saidulu, D., Majumder, A., Srivastava, A., Gupta, B., Gupta, A.K., 2021. 
Emerging contaminants in wastewater: a critical review on occurrence, existing 
legislations, risk assessment, and sustainable treatment alternatives. J. Environ. 
Chem. Eng. 9, 105966 https://doi.org/10.1016/J.JECE.2021.105966. 
Pariente, M.I., Segura, Y., Álvarez-Torrellas, S., Casas, J.A., de Pedro, Z.M., Diaz, E., 
García, J., López-Muñoz, M.J., Marugán, J., Mohedano, A.F., Molina, R., Munoz, M., 
Pablos, C., Perdigón-Melón, J.A., Petre, A.L., Rodríguez, J.J., Tobajas, M., 
Martínez, F., 2022. Critical review of technologies for the on-site treatment of 
hospital wastewater: from conventional to combined advanced processes. J. Environ. 
Manag. 320, 115769 https://doi.org/10.1016/J.JENVMAN.2022.115769. 
A. Majumder et al. 
https://doi.org/10.1016/j.jenvman.2023.119672
https://doi.org/10.1016/j.jenvman.2023.119672
https://doi.org/10.1016/j.enmm.2020.100336
https://doi.org/10.1006/rwfm.1999.1005
https://doi.org/10.1093/acrefore/9780199389414.013.495
https://doi.org/10.1093/acrefore/9780199389414.013.495
https://doi.org/10.1016/0043-1354(82)90249-4
http://refhub.elsevier.com/S0301-4797(23)02460-X/sref5
http://refhub.elsevier.com/S0301-4797(23)02460-X/sref5
http://refhub.elsevier.com/S0301-4797(23)02460-X/sref5
https://doi.org/10.1016/j.seppur.2022.122401
https://doi.org/10.1016/j.watres.2015.06.042
http://refhub.elsevier.com/S0301-4797(23)02460-X/sref8
http://refhub.elsevier.com/S0301-4797(23)02460-X/sref8
http://refhub.elsevier.com/S0301-4797(23)02460-X/sref8
https://doi.org/10.1016/j.jenvman.2023.117802
http://refhub.elsevier.com/S0301-4797(23)02460-X/sref10
http://refhub.elsevier.com/S0301-4797(23)02460-X/sref10
http://refhub.elsevier.com/S0301-4797(23)02460-X/sref10
http://refhub.elsevier.com/S0301-4797(23)02460-X/sref10
http://refhub.elsevier.com/S0301-4797(23)02460-X/sref11
http://refhub.elsevier.com/S0301-4797(23)02460-X/sref11
https://doi.org/10.1002/sca.21064
https://doi.org/10.1016/j.jenvman.2023.118686
https://doi.org/10.1016/j.jenvman.2023.118686
https://doi.org/10.1016/J.JECE.2022.107444
https://doi.org/10.1016/j.envint.2019.03.064
https://doi.org/10.1021/es304944c
https://doi.org/10.1021/es304944c
http://refhub.elsevier.com/S0301-4797(23)02460-X/sref17
http://refhub.elsevier.com/S0301-4797(23)02460-X/sref17
http://refhub.elsevier.com/S0301-4797(23)02460-X/sref17
http://refhub.elsevier.com/S0301-4797(23)02460-X/sref17
https://doi.org/10.1016/j.biortech.2015.05.073
https://doi.org/10.1016/j.cej.2023.143255
https://doi.org/10.1016/j.cej.2023.143255
https://doi.org/10.1016/J.JECE.2021.106496
https://doi.org/10.1016/j.jece.2020.104463
https://doi.org/10.1016/j.jece.2020.104812
https://doi.org/10.1016/j.colsurfa.2022.129250
https://doi.org/10.1016/j.envres.2019.108542
https://doi.org/10.1007/s10098-019-01669-1
https://doi.org/10.1016/B0-08-043751-6/08132-9
https://doi.org/10.1016/B0-08-043751-6/08132-9
https://doi.org/10.1007/s12665-013-2285-3
https://doi.org/10.1016/0584-8539(91)80042-H
https://doi.org/10.1016/0584-8539(91)80042-H
https://doi.org/10.1016/j.ecoenv.2018.01.040
https://doi.org/10.1016/j.ecoenv.2018.01.040
https://doi.org/10.1016/J.SCITOTENV.2015.02.104
https://doi.org/10.1007/s10904-020-01847-5
https://doi.org/10.1007/s10904-020-01847-5
https://doi.org/10.1016/J.JECE.2021.105966
https://doi.org/10.1016/J.JENVMAN.2022.115769
Journal of Environmental Management 351 (2024) 119672
12
Pastre, M.M.G., Cunha, D.L., Marques, M., 2023. Design of biomass-based composite 
photocatalysts for wastewater treatment: a review over the past decade and future 
prospects. Environ. Sci. Pollut. Res. 30, 9103–9126. https://doi.org/10.1007/ 
s11356-022-24089-z. 
Priyanka, Srivastava, V.C., 2013. Photocatalytic oxidation of dye bearing wastewater by 
iron doped zinc oxide. Ind. Eng. Chem. Res. 52 https://doi.org/10.1021/ie401973r. 
Roberts, P.H., Thomas, K.V., 2006. The occurrence of selected pharmaceuticals in 
wastewater effluent and surface waters of the lower Tyne catchment. Sci. Total 
Environ. 356, 143–153. https://doi.org/10.1016/j.scitotenv.2005.04.031. 
Rodríguez-Mozaz, S., Huerta, B., Barceló, D., 2016. Bioaccumulation of emerging 
contaminants in aquatic biota: patterns of pharmaceuticals in mediterranean river 
networks. Emerg. Contam. River Ecosyst. Occur. Eff. Under Mult. Stress Cond. 
121–141. 
Saidulu, D., Gupta, B., Gupta, A.K., Ghosal, P.S., 2021. A review on occurrences, eco- 
toxic effects, and remediation of emerging contaminants from wastewater : special 
emphasis on biological treatment based hybrid systems. J. Environ. Chem. Eng. 9, 
105282 https://doi.org/10.1016/j.jece.2021.105282. 
Saidulu, D., Srivastava, A., Gupta, A.K., 2023. Elucidating the performance of integrated 
anoxic/oxic moving bed biofilm reactor: assessment of organics and nutrients 
removal and optimization using feed forward back propagation neural network. 
Bioresour. Technol. 371, 128641 https://doi.org/10.1016/j.biortech.2023.128641. 
Setiawan, Y., Hardiani, H., 2020. The potential of anaerobic-constructed wetland system 
for wastewater treatment of rice straw pulping. In: IOP Conference Series: Materials 
Science and Engineering. IOP Publishing, 12070. 
Sharma, R., Gupta, S.K., 2004. Influence of chemical oxygen demand/total Kjeldahl 
nitrogen ratio and sludge age on nitrification of nitrogenous wastewater. Water 
Environ. Res. 76 https://doi.org/10.2175/106143004x141681. 
Shen, Y., Huang, P.C., Huang, C., Sun, P., Monroy, G.L., Wu, W., Lin, J., Espinosa- 
Marzal, R.M., Boppart, S.A., Liu, W.T., Nguyen, T.H., 2018. Effect of divalent ions 
and a polyphosphate on composition, structure, and stiffness of simulated drinking 
water biofilms. npj Biofilms Microbiomes 4. https://doi.org/10.1038/s41522-018- 
0058-1. 
Srivastava, P., Abbassi, R., Kumar Yadav, A., Garaniya, V., Kumar, N., Khan, S.J., 
Lewis, T., 2020. Enhanced chromium(VI) treatment in electroactive constructed 
wetlands: influence of conductive material. J. Hazard Mater. 387, 121722 https:// 
doi.org/10.1016/j.jhazmat.2019.121722. 
Staal, L.B., Petersen, A.B., Jørgensen, C.A., Nielsen, U.G., Nielsen, P.H., Reitzel, K., 2019. 
Extraction and quantification of polyphosphates in activated sludge from waste 
water treatment plants by 31P NMR spectroscopy. Water Res. 157 https://doi.org/ 
10.1016/j.watres.2019.03.065. 
Sundberg, C., Jönsson, H., 2008. Higher pH and faster decomposition in biowaste 
composting by increased aeration. Waste Manag. 28 https://doi.org/10.1016/j. 
wasman.2007.01.011. 
Tang, S., Liao, Y., Xu, Y., Dang, Z., Zhu, X., Ji, G., 2020. Microbial coupling mechanisms 
of nitrogen removal in constructed wetlands: a review. Bioresour. Technol. 314, 
123759 https://doi.org/10.1016/j.biortech.2020.123759. 
Tchobanoglous, G., Burton, F.L., Stensel, H.D., 2014. WastewaterEngineering: 
Treatment and Resource Recovery. Metcalf & Eddy, Inc. McGraw-Hill Education, 
Boston. 
Teodosiu, C., Gilca, A.F., Barjoveanu, G., Fiore, S., 2018. Emerging pollutants removal 
through advanced drinking water treatment: a review on processes and 
environmental performances assessment. J. Clean. Prod. https://doi.org/10.1016/j. 
jclepro.2018.06.247. 
Trovati, G., Sanches, E.A., Neto, S.C., Mascarenhas, Y.P., Chierice, G.O., 2010. 
Characterization of polyurethane resins by FTIR, TGA, and XRD. J. Appl. Polym. Sci. 
115 https://doi.org/10.1002/app.31096. 
Valdés, M.E., Huerta, B., Wunderlin, D.A., Bistoni, M.A., Barceló, D., Rodriguez- 
Mozaz, S., 2016. Bioaccumulation and bioconcentration of carbamazepine and other 
pharmaceuticals in fish under field and controlled laboratory experiments. Evidences 
of carbamazepine metabolization by fish. Sci. Total Environ. 557, 58–67. 
Varma, M., Gupta, A.K., Ghosal, P.S., Majumder, A., 2021. A review on performance of 
constructed wetlands in tropical and cold climate: insights of mechanism, role of 
influencing factors, and system modification in low temperature. Sci. Total Environ. 
9, 142540 https://doi.org/10.1016/j.scitotenv.2020.142540. 
Verlicchi, P., Al Aukidy, M., Galletti, A., Petrovic, M., Barceló, D., 2012. Hospital 
effluent: Investigation of the concentrations and distribution of pharmaceuticals and 
environmental risk assessment. Sci. Total Environ. 430, 109–118. https://doi.org/ 
10.1016/J.SCITOTENV.2012.04.055. 
Vernouillet, G., Eullaffroy, P., Lajeunesse, A., Blaise, C., Gagné, F., Juneau, P., 2010. 
Toxic effects and bioaccumulation of carbamazepine evaluated by biomarkers 
measured in organisms of different trophic levels. Chemosphere 80, 1062–1068. 
Wickramasinghe, N.N., Hlaing, M.M., Ravensdale, J.T., Coorey, R., Chandry, P.S., 
Dykes, G.A., 2020. Characterization of the biofilm matrix composition of 
psychrotrophic, meat spoilage pseudomonads. Sci. Rep. 10 https://doi.org/10.1038/ 
s41598-020-73612-0. 
Wilkinson, J.L., Boxall, A.B.A., Kolpin, D.W., Leung, K.M.Y., Lai, R.W.S., Galbán- 
Malagón, C., Adell, A.D., Mondon, J., Metian, M., Marchant, R.A., Bouzas- 
Monroy, A., Cuni-Sanchez, A., Coors, A., Carriquiriborde, P., Rojo, M., Gordon, C., 
Cara, M., Moermond, M., Luarte, T., Petrosyan, V., Perikhanyan, Y., Mahon, C.S., 
McGurk, C.J., Hofmann, T., Kormoker, T., Iniguez, V., Guzman-Otazo, J., Tavares, J. 
L., Gildasio De Figueiredo, F., Razzolini, M.T.P., Dougnon, V., Gbaguidi, G., 
Traoré, O., Blais, J.M., Kimpe, L.E., Wong, M., Wong, D., Ntchantcho, R., Pizarro, J., 
Ying, G.-G., Chen, C.-E., Páez, M., Martínez-Lara, J., Otamonga, J.-P., Poté, J., Ifo, S. 
A., Wilson, P., Echeverría-Sáenz, S., Udikovic-Kolic, N., Milakovic, M., Fatta- 
Kassinos, D., Ioannou-Ttofa, L., Belušová, V., Vymazal, J., Cárdenas-Bustamante, M., 
Kassa, B.A., Garric, J., Chaumot, A., Gibba, P., Kunchulia, I., Seidensticker, S., 
Lyberatos, G., Halldórsson, H.P., Melling, M., Shashidhar, T., Lamba, M., Nastiti, A., 
Supriatin, A., Pourang, N., Abedini, A., Abdullah, O., Gharbia, S.S., Pilla, F., 
Chefetz, B., Topaz, T., Yao, K.M., Aubakirova, B., Beisenova, R., Olaka, L., Mulu, J. 
K., Chatanga, P., Ntuli, V., Blama, N.T., Sherif, S., Aris, A.Z., Looi, L.J., Niang, M., 
Traore, S.T., Oldenkamp, R., Ogunbanwo, O., Ashfaq, M., Iqbal, M., Abdeen, Z., 
O’Dea, A., Morales-Saldaña, J.M., Custodio, M., de la Cruz, H., Navarrete, I., 
Carvalho, F., Gogra, A.B., Koroma, B.M., Cerkvenik-Flajs, V., Gombač, M., 
Thwala, M., Choi, K., Kang, H., Ladu, J.L.C., Rico, A., Amerasinghe, P., Sobek, A., 
Horlitz, G., Zenker, A.K., King, A.C., Jiang, J.-J., Kariuki, R., Tumbo, M., Tezel, U., 
Onay, T.T., Lejju, J.B., Vystavna, Y., Vergeles, Y., Heinzen, H., Pérez-Parada, A., 
Sims, D.B., Figy, M., Good, D., Teta, C., 2022. Pharmaceutical pollution of the 
world’s rivers. Proc. Natl. Acad. Sci. USA 119, e2113947119. https://doi.org/ 
10.1073/pnas.2113947119. 
Yadu, A., Sahariah, B.P., Anandkumar, J., 2018. Influence of COD/ammonia ratio on 
simultaneous removal of NH4+-N and COD in surface water using moving bed batch 
reactor. J. Water Process Eng. 22 https://doi.org/10.1016/j.jwpe.2018.01.007. 
Yan, Liying, Zhang, S., Lin, D., Guo, C., Yan, Lingling, Wang, S., He, Z., 2018. Nitrogen 
loading affects microbes, nitrifiers and denitrifiers attached to submerged 
macrophyte in constructed wetlands. Sci. Total Environ. 622–623. https://doi.org/ 
10.1016/j.scitotenv.2017.11.234. 
Ye, Y., Feng, Y., Bruning, H., Yntema, D., Rijnaarts, H.H.M., 2018. Photocatalytic 
degradation of metoprolol by TiO2 nanotube arrays and UV-LED: effects of catalyst 
properties, operational parameters, commonly present water constituents, and 
photo-induced reactive species. Appl. Catal. B Environ. 220, 171–181. https://doi. 
org/10.1016/j.apcatb.2017.08.040. 
Zhou, X., Wu, S., Wang, R., Wu, H., 2019. Nitrogen removal in response to the varying C/ 
N ratios in subsurface flow constructed wetland microcosms with biochar addition. 
Environ. Sci. Pollut. Res. 26, 3382–3391. https://doi.org/10.1007/s11356-018- 
3871-4. 
A. Majumder et al. 
https://doi.org/10.1007/s11356-022-24089-z
https://doi.org/10.1007/s11356-022-24089-z
https://doi.org/10.1021/ie401973r
https://doi.org/10.1016/j.scitotenv.2005.04.031
http://refhub.elsevier.com/S0301-4797(23)02460-X/sref37
http://refhub.elsevier.com/S0301-4797(23)02460-X/sref37
http://refhub.elsevier.com/S0301-4797(23)02460-X/sref37
http://refhub.elsevier.com/S0301-4797(23)02460-X/sref37
https://doi.org/10.1016/j.jece.2021.105282
https://doi.org/10.1016/j.biortech.2023.128641
http://refhub.elsevier.com/S0301-4797(23)02460-X/sref40
http://refhub.elsevier.com/S0301-4797(23)02460-X/sref40
http://refhub.elsevier.com/S0301-4797(23)02460-X/sref40
https://doi.org/10.2175/106143004x141681
https://doi.org/10.1038/s41522-018-0058-1
https://doi.org/10.1038/s41522-018-0058-1
https://doi.org/10.1016/j.jhazmat.2019.121722
https://doi.org/10.1016/j.jhazmat.2019.121722
https://doi.org/10.1016/j.watres.2019.03.065
https://doi.org/10.1016/j.watres.2019.03.065
https://doi.org/10.1016/j.wasman.2007.01.011
https://doi.org/10.1016/j.wasman.2007.01.011
https://doi.org/10.1016/j.biortech.2020.123759
http://refhub.elsevier.com/S0301-4797(23)02460-X/sref47
http://refhub.elsevier.com/S0301-4797(23)02460-X/sref47
http://refhub.elsevier.com/S0301-4797(23)02460-X/sref47
https://doi.org/10.1016/j.jclepro.2018.06.247
https://doi.org/10.1016/j.jclepro.2018.06.247
https://doi.org/10.1002/app.31096
http://refhub.elsevier.com/S0301-4797(23)02460-X/sref50
http://refhub.elsevier.com/S0301-4797(23)02460-X/sref50
http://refhub.elsevier.com/S0301-4797(23)02460-X/sref50
http://refhub.elsevier.com/S0301-4797(23)02460-X/sref50
https://doi.org/10.1016/j.scitotenv.2020.142540
https://doi.org/10.1016/J.SCITOTENV.2012.04.055
https://doi.org/10.1016/J.SCITOTENV.2012.04.055
http://refhub.elsevier.com/S0301-4797(23)02460-X/sref53
http://refhub.elsevier.com/S0301-4797(23)02460-X/sref53
http://refhub.elsevier.com/S0301-4797(23)02460-X/sref53
https://doi.org/10.1038/s41598-020-73612-0
https://doi.org/10.1038/s41598-020-73612-0
https://doi.org/10.1073/pnas.2113947119
https://doi.org/10.1073/pnas.2113947119
https://doi.org/10.1016/j.jwpe.2018.01.007
https://doi.org/10.1016/j.scitotenv.2017.11.234
https://doi.org/10.1016/j.scitotenv.2017.11.234
https://doi.org/10.1016/j.apcatb.2017.08.040
https://doi.org/10.1016/j.apcatb.2017.08.040
https://doi.org/10.1007/s11356-018-3871-4
https://doi.org/10.1007/s11356-018-3871-4
	Combination of advanced biological systems and photocatalysis for the treatment of real hospital wastewater spiked with car ...
	1 Introduction
	2 Materials and methods
	2.1 Location of the pilot-scale treatment unit and treatment units employed
	2.2 Acclimatization