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Emerging Contaminants and Treatment Options in Water Recycling for Indirect Potable Use


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Solutions to global water stress problems are urgently needed yet must be sustainable, economical and safe. The utilisation of alternative water sources like reclaimed municipal wastewater is one of the most obvious and promising options in integrated water resources management. Among the various beneficial uses of reclaimed wastewater Aquifer Recharge (AR) receives growing attention because it features advantages such as additional natural treatment, storage capacity to buffer seasonal variations of supply and demand as well as mixing with natural water bodies which promotes the acceptance of further uses, particularly indirect potable use. Major concerns about the safety of this exploitation route of an alternative water source are connected to microbial and chemical contaminants occurring in wastewater, among which are emerging trace organics like endocrine disrupters and pharmaceuticals. This paper reviews the current international debate about the relevance of emerging contaminants and technical mitigation options in water recycling for indirect potable use.
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Emerging contaminants and treatment options in water
recycling for indirect potable use
T. Wintgens, F. Salehi, R. Hochstrat and T. Melin
T. Wintgens
F. Salehi
R. Hochstrat
T. Melin
Chemical Engineering Department,
RWTH Aachen University,
Turmstrasse 46, 52056 Aachen,
Solutions to global water stress problems are urgently needed yet must be sustainable,
economical and safe. The utilisation of alternative water sources like reclaimed municipal
wastewater is one of the most obvious and promising options in integrated water resources
management. Among the various beneficial uses of reclaimed wastewater Aquifer Recharge (AR)
receives growing attention because it features advantages such as additional natural treatment,
storage capacity to buffer seasonal variations of supply and demand as well as mixing with
natural water bodies which promotes the acceptance of further uses, particularly indirect potable
use. Major concerns about the safety of this exploitation route of an alternative water source are
connected to microbial and chemical contaminants occurring in wastewater, among which are
emerging trace organics like endocrine disrupters and pharmaceuticals. This paper reviews the
current international debate about the relevance of emerging contaminants and technical
mitigation options in water recycling for indirect potable use.
Key words
emerging contaminants, indirect potable reuse, water recycling
Population growth, increased industrial activities in many
parts of the world as well as the estimated impacts of
climate change will exceed various pressures on the water
supply systems (EEA 2007). Particularly in developing
countries there is a need to dramatically enlarge the access
to safe and piped water (UN 2006). Considering the growing
burden on freshwater resources, particularly the over-
abstraction of groundwater, the deterioration of ground-
water quality, and saltwater intrusion into coastal aquifers,
the utilisation of alternative water sources is a promising
option to supplement water supply and restore natural
resources (EEA 1999; Margat & Valle
e 2000). Among the
alternative water sources are seawater, brackish ground-
water, urban storm water, collected rain water as well as
reclaimed water which can be used for different beneficial
Global water demand will continue to increase and is
expected to reach probably 70% of the available freshwater
resources till 2025 (UN 2006). Furthermore, these resources
are unequally distributed and often of poor quality so that
numerous regions in the world face rising water stress.
Superposed on the evolution of demand are natural and
man-made variations of water availability.
The water stress index the ratio of a country’s total
water withdrawal to its total renewable freshwater
resources serves as a rough indicator for the pressure
exerted on water resources. Not all water uses are causing
comparable stress. A ratio in the range of 10% to 20%
indicates that water availability is becoming a constraint
on development. A water stress index above 20% is
supposed to necessitate comprehensive water manage-
ment efforts and actions to resolve conflicts among
competing uses (OECD 2003). It is striking that approxi-
mately half of the European countries, representing
almost 70% of the population, are already facing water
stress issues today.
doi: 10.2166/wst.2008.799
99 Q IWA Publishing 2008 Water Science & Technology—WST
Water reclamation and reuse applications
Municipal wastewater including stormwater can be consi-
dered as an alternative water source if treated appropriately
for the intended use. This is highlighted by the Urban
Wastewater Treatment Directive (91/271/EEC) and by the
Water Framework Directive (2000/60/EC) encouraging
“reuse measures” and “artificial recharge” as supplementary
measures that can be applied to reach the fixed environ-
mental objectives for surface and groundwater bodies.
Reclamation and reuse of municipal wastewater is a
method to mitigate increasingly evident water stress arising
in many regions of the world from water scarcity and water
quality degradation. The proposed implementation of water
reclamation in integrated water resources management is
driven by sustainability issues, potential cost-advantages
and climate change conditions. The socio-cultural environ-
ment often drives and determines the appropriateness of
technical solutions (Bixio et al. 2005; Asano et al. 2006).
Indirect potable reuse
Indirect potable reuse can be regarded as any augmentation
of water bodies utilised for drinking water supplies by
wastewater treatment plant effluents or overflows from
combined sewer systems (Asano et al. 2006). One can
distinguish between unintended or de facto indirect potable
reuse which happens along major river catchments around
the world, where drinking water resources are influenced by
wastewater discharges as observed on basis of anthropo-
genic tracer substances, (Ternes & Joss 2006; Weil &
Knepper 2006; Dillon & Jiminez 2007) as well as planned or
intended indirect potable reuse. Planned indirect potable
reuse is a measure to supplement public water supply by the
utilisation of reclaimed water through introduction in a
drinking water reservoir or via managed aquifer recharge.
Managed recharge has for a long time provided means to
mitigate depletion of groundwater levels, to protect coastal
aquifers from saltwater intrusion, and to store surface water
for future use (Kanarek & Michail 1996; Mills et al. 1998;
Bouwer 2000). Aquifer storage has some advantages over
surface water reservoirs which might be more costly and
environmentally questionable. Moreover, soil percolation
and aquifer storage act as treatment steps while avoiding
evaporation as well as taste and odour problems due to algae
growth in surface storage (Dillon 2000; Asano & Cotruvo
2004). Recharge can be performed in two ways: direct or
indirect. If conducted by infiltration and percolation through
soil and subsoil, the recharge processes, e.g. by so-called Soil
Aquifer Treatment (SAT), offer an additional barrier. Mixing
reclaimed wastewater with natural groundwater prior to any
intended use also positively influences the public acceptance
of a reuse scheme.
The concept of Aquifer Recharge (AR) offers potential
for various subsequent uses like irrigation, industrial
process water and augmentation of public water supplies.
The latter, indirect potable use, is certainly one of the most
challenging water reclamation and reuse applications with a
high demand in terms of safety because of the potential use
as drinking water (whose quality criteria are fixed in
directive 98/83/EC) and the general level of protection
required for groundwater resources as laid down in the
directive on the protection of groundwater against pollution
and deterioration (2006/118/EC). Even if drinking water
supplementation is not explicitly foreseen in an aquifer
recharge project, the provision of drinking water quality in
the recovered product is a common bottom line in many
applications, e.g. in Israel where the Dan Region Recla-
mation and SAT scheme provides “accidental drinking
water quality” on a large scale (Mekorot 2003).
Water quality criteria
According to a recent review conducted by Asano & Cotruvo
(2004) the main concerns in indirect potable reuse are health
risks resulting from pathogens and trace chemicals as well as
nitrate. Among the organic pollutants there is a range of so
called emerging contaminants such as endocrine disrupting
compounds (EDC), pharmaceutically active compounds
(PhAC), personal care products (PCP) and disinfection
by-products (DBP). The occurrence of these emerging
contaminants in the aquatic environment including surface
and groundwaters, and wastewater sludges as well as
drinking water has been studied (Heberer 2002; Ternes &
100 T. Wintgens et al.
Water recycling for indirect potable use Water Science & Technology—WST
Table 1
Emerging contaminants in indirect potable reuse and aquifer recharge schemes
Scheme and sample point Compound Concentration [ng/L] Reference
North City Water Reclamation Plant San Diego (CA) Advanced Water Treatment Pilot
V Tertiary effluent Sulfamethaxoazole 892 DeCarolis et al. 2006
V Reverse osmosis permeate Sulfamethaxoazole 2.9 DeCarolis et al. 2006
V UV þ Peroxide product Sulfamethaxoazole , 1.0 DeCarolis et al. 2006
V Tertiary effluent Iopromide 632 DeCarolis et al. 2006
V Reverse osmosis permeate Iopromide 1.4 DeCarolis et al. 2006
V UV þ Peroxide product Iopromide , 1.0 DeCarolis et al. 2006
Bolivar Aquifer Storage and Recovery Scheme (South Australia)
V Reclaimed water Atrazine 9.2 Overacre et al. 2006
V Groundwater (5 month storage) Atrazine 4.5 Overacre et al. 2006
V Groundwater (11 month storage) Atrazine 1.8 Overacre et al. 2006
V Reclaimed water Estrone 32 Overacre et al. 2006
V Groundwater (5 month storage) Estrone 24 Overacre et al. 2006
V Groundwater (11 month storage) Estrone 11 Overacre et al. 2006
Temporary Hanningfield reservoir augmentation by Chelmsford effluent (UK)
V Sewage plant effluent Estrone 8 33 Gomes & Lester 2003
V UV-treated effluent Estrone , 1-20 Gomes & Lester 2003
Infiltration of secondary effluent into groundwater via
a wetland upstream of a drinking water facility (Germany)
V Receiving surface water Carbamazepin 1,100 Bergman et al. 2003
V Wetland Carbamazepin 500600 Bergman et al. 2003
V Groundwater (420 m from infiltration) Carbamazepin 530 Bergman et al. 2003
Irrigation of treated wastewater in Braunschweig, Germany
V Tertiary effluent Sulfamethaxoazole 620 ^ 90 Ternes et al. 2007
V Groundwater (in the irrigation area) Sulfamethaxoazole , LOQ 110 Ternes et al. 2007
V Tertiary effluent Carbamazepine 2,100 ^ 700 Ternes et al. 2007
V Groundwater (in the irrigation area) Carbamazepine , LOQ 570 Ternes et al. 2007
V Tertiary effluent Diatrizoate 1,700 ^ 3,300 Ternes et al. 2007
V Groundwater Diatrizoate 1,600 9,600 Ternes et al. 2007
101 T. Wintgens et al.
Water recycling for indirect potable use Water Science & Technology—WST
Joss 2006). A particular substance of concern is N-nitrosodi-
methylamine (NDMA) which was found to be a possible
by-product in water and wastewater disinfection (Mitch &
Sedlak 2002) and is characterised as highly carcinogenic.
In contrast to the wide range of EDCs, PhACs and
PCPs, only DBPs are currently considered in water related
pieces of regulation and supra-national recommendations,
particularly in drinking water quality requirements such as
the WHO Guidelines for Drinking-water Quality (WHO
2004), the European Drinking Water Directive and the US
National Primary Drinking Water Regulations (US EPA
2006). Guidelines for indirect potable use make regularly
reference to drinking water quality standards and add a
number of specific criteria such as absence of faecal
contamination and low TOC (. 3 mg/L) (US EPA 2004;
Salgot et al. 2006). While not formally incorporated into
Table 1
Scheme and sample point Compound Concentration [ng/L] Reference
Comparing MF, RO and soil-aquifer treatment
for indirect potable reuse of water (USA)
V Tertiary effluent EDTA 35,400 ^ 27,600 Drewes et al. 2003
V Microfiltration permeate EDTA 5,600 Drewes et al. 2003
V Nanofiltration permeate EDTA , LOQ Drewes et al. 2003
V Reverse osmosis permeate EDTA , LOQ Drewes et al. 2003
V Soil-aquifer treatment EDTA 3,960 ^ 3,180 Drewes et al. 2003
V Tertiary effluent APECs 55,800 ^ 59,400 Drewes et al. 2003
V Microfiltration permeate APECs 23,400 Drewes et al. 2003
V Nanofiltration permeate APECs , LOQ Drewes et al. 2003
V Reverse osmosis permeate APECs , LOQ Drewes et al. 2003
V Soil-aquifer treatment APECs 680 ^ 1,140 Drewes et al. 2003
Water samples influenced by wastewater
in Berlin (Germany)
V Surface water p-TSA , 1,150 Richter et al. 2007
V Groundwater (directly below a former
sewage farm)
p-TSA , 40,800 Richter et al. 2007
V Drinking water p-TSA , 270 Richter et al. 2007
V Surface water BSA , 520 Richter et al. 2007
V Groundwater (directly below a former
sewage farm)
BSA , 1,220 Richter et al. 2007
V Drinking water BSA , 50 Richter et al. 2007
LOQ ¼ limit of quantification, p-TSA ¼ paratoluenesulfonamide, BSA ¼ benzenesulfonamide, EDTA ¼ ethylenediaminetetraacetic acid, APECs ¼ alkylphenolpolyethoxycarboxylates.
102 T. Wintgens et al.
Water recycling for indirect potable use Water Science & Technology—WST
national drinking water standards the Californian Office of
Environmental Health Hazard Assessment issued 2006 a
Public Health Goal (PHG) for NDMA of 3 ng/L (OEHHA
2006). The California Department of Health Services’
Division of Drinking Water and Environmental Manage-
ment (DDWEM) has established a notification level of
10 ng/L for a number of nitrosamines (DHS 2006). Without a
direct link to indirect potable use, but to guideline values for
emerging contaminants in the aquatic environment, the
European Parliament Committee on the Environment,
Public Health and Food Safety has approved a proposal in
2007 for an extension of the list of the priority substances to
be included in the Annex X of the Water Framework
Directive (EPC 2007), containing trace organics as bisphenol
A, carbamazepine, clotrimazole and diclofenac.
Occurrence and fate of emerging contaminants
The occurrence and fate of emerging contaminants has been
monitored in a number of indirect potable reuse and aquifer
recharge schemes (PUB 2002; Gomes & Lester 2003; Asano
et al.2006; Snyder et al.2007). Table 1 summarises selected
data on the occurrence and fate of emerging contaminants
obtained from monitoring of both planned and unplanned
Table 2
Water reclamation schemes investigated in RECLAIM WATER (
Site location & capacity Scheme description
Sabadell 30 km from Barcelona,
Spain Capacity: 25,000 m
Secondary treated wastewater effluent discharged into a river bed where it infiltrates and is
recovered. The water is then disinfected (UV) and distributed for parks irrigation.
Salento Region, south of Bari,
Italy Capacity: 12,000 m
Secondary treated municipal effluent is transported to aquifer injection. Recharge acts as a
salt intrusion barrier and resource is also used as drinking water source.
Shafdan Negev, Israel
Capacity: 342,000 m
Secondary wastewater from the Tel-Aviv area is recharged to an aquifer via a soil aquifer
treatment (SAT) system. Recovered water is primarily used for irrigation but has accidental
drinking water quality.
Gaobeidian Beijing, China
Capacity: 650 m
Tertiary effluent is used for aquifer recharge. Treatment is provided by coagulation, filtration
and ozonation (in test) prior to infiltration and recharge.
Adelaide Salisbury, South Australia
Capacity: 1,100 m
Wetland treated urban stormwater injected into a brackish aquifer. Water recovered via
separate recovery wells. Recovered water intended for drinking supplies, and until proven will
be used for irrigation.
Torrele (Wulpen) Belgium
Capacity: 8,640 m
Infiltration: 2.5 million m
/ year
Tertiary treated municipal effluent is upgraded by microfiltration and reverse osmosis, and
then infiltrated via an infiltration pond to prevent salt intrusion and to recharge an aquifer
used for drinking water production.
Mezquital Valley (State of Mexico)
Mexico Infiltration:
630 million m
Wastewater mixed with stormwater and surface water is discharged to an irrigated area of
more than 76,000 ha. About 40% of the irrigation water infiltrates into the aquifer. The water
is recovered via separate wells and springs. 206 well systems, 31 springs, and 63 waterwheels
are in operation. Recovered water is chlorinated and distributed for drinking water supply,
industrial use, irrigation and other purposes (bathing, swimming, washing).
Atlantis (Cape Town) South Africa
Capacity: 15,000 m
Infiltration: 2.7 million m
Urban stormwater run-off, is collected via a series of detention basins and blended with
secondary treated domestic wastewater and recharged up-gradient of the production well
field for augmenting the water supply. The blend of natural groundwater and recharged water
abstracted from the well field is used as potable water supply for the town of Atlantis.
NEWATER Singapore
Capacity: 150,000 m
NEWATER is treated used water further purified using dual-membrane (microfiltration and
reverse osmosis) and UV treatment. Four NEWATER factories are in operation
supplementing Singapore’s water supplies, part of the product water is use to augment
drinking water reservoirs.
103 T. Wintgens et al.
Water recycling for indirect potable use Water Science & Technology—WST
indirect potable reuse as well as aquifer recharge schemes.
To overcome the limitations of compound-specific tests with
respect to the potential health hazards toxicological tests
have also been carried out with bio-assays in a number of
indirect potable reuse schemes. Both toxicological tests as
well as a limited number of epidemiological tests could not
show that a higher health risk is connected to water recycling
than to the use of the conventional sources considered (PUB
2002; Khan & Roser 2007)
Wastewater is generally more polluted than most drinking
water sources and hence requires more extensive treatment
prior to indirect potable use. The treatment technology for
these ambitious goals is generally available and implemented
in full scale (e.g. in Orange County, Singapore and Wulpen/
Belgium). Examples exist where the aquifer is recharged with
secondary treated effluent only and the soil-aquifer system is
used as treatment and storage, as it is the case in economically
developed countries such as Israel, USA and Australia
(International Water and Irrigation Review 1999)aswellas
in countries with transient economies such as Mexico,
South Africa, Thailand and Peru (Dillon & Jiminez 2007).
The natural attenuation processes occurring in the soil and
sub-soil, particularly in the vadose zone, have shown to be
quite effective with respect to trace organic removal (Ternes
et al.2007). On the other hand, in the last decade the common
practice in Western Countries is rather to apply tertiary
(e.g. coagulation, filtration, disinfection) or quaternary treat-
ment (various types of double membrane systems, as it is the
case in Belgium, California, Singapore, Australia and Nami-
bia) before infiltration and potable use (Bixio et al. 2005).
The effectiveness of a range of intensive water recla-
mation technologies such as conventional and membrane
coupled (MBR) activated sludge treatment, membrane
effluent filtration with porous and dense membrane pro-
cesses, activated carbon adsorption as well as different
oxidation processes (Ozone, UV þ Ozone, UV þ Per-
oxide) have been investigated in a number of studies
(Asano et al. 2006; Ternes & Joss 2006; Snyder et al.
2007). It seems obvious from the result of these investi-
gations that an almost complete retention of a wide range of
emerging contaminants can be achieved with multi-barrier
treatment processes. Particularly difficult is the removal of
NDMA; advanced oxidation processes with UV and H
have been implemented in indirect potable reuse schemes in
the US to cope with this problem (Asano et al. 2006).
Technologies applied in full scale water reuse schemes
There is a number of treatment technologies applied in
indirect potable reuse projects ranging from soil application
of raw wastewater to highly engineered double membrane
systems plus advanced oxidation. Compilations of the
different treatment trains utilised in various schemes world-
wide can be obtained e.g. from Asano et al. (2006), Ternes &
Joss (2006), Dillon & Jimenez (2007). A number of different
indirect potable reuse and managed groundwater recharge
schemes are under investigation by the European Project
partnership RECLAIM WATER. The case studies investi-
gated there also with respect to the occurrence and fate of
trace organics are listed in Table 2.
Table 3
Nanofiltration application studies in water and wastewater applications
Application Treatment aims Source
Drinking water treatment (Groundwater) Water softening Gorenflo et al. (2002)
Drinking water treatment (Surface water) TOC removal Beros et al. (2003)
Textile industry Dye removal Van der Bruggen et al. (2004)
Desalination Salt removal Melin & Rautenbach (2007)
Water reclamation TOC removal Meier & Melin (2005)
104 T. Wintgens et al.
Water recycling for indirect potable use Water Science & Technology—WST
Emerging technologies
Among the emerging technologies for indirect potable use
nanofiltration should be highlighted as a treatment tech-
nology which can remove a wide range of microbiological
as well as chemical contaminants (Scha¨ fer et al. 2005).
Nanofiltration can be considered as an alternative to
reverse osmosis technology where a lower degree of
desalination is required. With a molecular weight cut-off
above 200 g/mol it is a promising treatment option for a
variety of emerging trace contaminants. Nanofiltration has
Table 4
Retention of organic micropollutants with NF and RO membranes
Compounds Substance type Membrane type Retention [%] Source
Bisphenol A EDC NF 1.999.7
Gallenkemper (2005)
Bisphenol A EDC RO 1883 Kimura et al. (2004)
Bisphenol A EDC NF 47 . 99 Agenson et al. (2003)
Nonylphenol EDC NF 90.599.3
Gallenkemper (2005)
Estrone EDC NF/RO 13 . 80 Nghiem et al. (2004)
Estrone EDC NF 80 . 95 Scha¨ fer et al. (2003)
Estrone EDC NF 6583 Braeken et al. (2005)
Estrone EDC NF 40 . 99 Weber (2004)
Estradiol EDC NF 20 . 80 Nghiem et al. (2004)
Estradiol EDC NF 49 . 99 Weber (2004)
Estradiol EDC RO 2983 Kimura et al. (2004)
Diethylstilbestrol EDC NF 60 . 99 Weber (2004)
Mestranol EDC NF 90 . 99 Weber (2004)
Ethinylestradiol EDC NF 41 . 99 Weber (2004)
Atrazine Pesticide NF 5992 Zhang et al. (2004)
Atrazine Pesticide NF 8695 Chen et al. (2004)
Atrazine Pesticide NF . 80 Plakas et al. (2006)
Simazine Pesticide NF 45 . 80 Zhang et al. (2004)
Primidone Pharmaceutical RO 85 87 Kimura et al. (2004)
Isopropylantipyrine Pharmaceutical RO 6978 Kimura et al. (2004)
Carbamazipine Pharmaceutical RO 8591 Kimura et al. (2004)
Sufamethoxazole Pharmaceutical RO 7082 Kimura et al. (2004)
retentions are corrected by the effect of concentration polarisation.
105 T. Wintgens et al.
Water recycling for indirect potable use Water Science & Technology—WST
been investigated for a number of purification applications
as shown in Table 3.
The largest full scale implementation of nanofiltration
in water treatment applications is the Me
ry sur Oise plant
close to Paris that was built to reduce the high organic load
in the raw surface water utilised for drinking water
production. Seasonal pesticide issues were the reason to
complement the multi-barrier concept by a dense mem-
brane process (Cyna et al. 2002; Beros et al. 2003).
In a number of studies the organic micropollutant removal
capacity of nanofiltration has been investigated and compared
to reverse osmosis (Table 4). Medium to high removal rates
have been observed for endocrine disrupting compounds,
pesticides and pharmaceutically active compounds.
In a recent study conducted in Germany on the appli-
cation of dense membrane processes to treat River Rhine bank
filtrate reverse osmosis was preferred when compared to
nanofiltration due to the even higher micropollutant retention
detected in this case (Loi-Bru
gger et al.2007).
The authors acknowledge the European Commission for
funding the RECLAIM WATER project on “Water recla-
mation technologies for safe groundwater recharge”, 6th
Framework Programme on Research and Technological
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Water recycling for indirect potable use Water Science & Technology—WST
... Nowadays there is a serious danger to human's health due to its pollution. Environmental pollutants have become a major challenge in the world due to industrialization and population growth, therefore, it is necessary to treat wastewater from organic pollutants [1][2][3][4]. Some organic pollutants, such as industrial wastes, detergents, synthetic solvents, dyes, pesticides, food additives, pharmaceuticals, and other organic compounds have a direct impact on water quality [5][6][7][8][9][10]. ...
... The RSM of the proposed linear and Quadratic models were applied, and four different factors were studied. The four main and important factors are pH (3)(4)(5)(6)(7)(8)(9)(10)(11), amount of photocatalyst (0.01-0.03 g), Time graphical representations of the interaction between variables factors mass of composites and time. Figure 12 illustrates the compound impact of the radiation time and mass of nanocomposite on the degradation efficiency in the modified quadratic model and linear model respectively for rGO/TiO 2 embedded HCP and GO/TiO 2 embedded HCP. Figure 12 shows that the Rh.B dye degradation process increases by the increasing mass of nanocomposites. ...
Nanocomposites (r)GO/TiO2/hyper crosslinked polymer (HCP) were prepared using ultrasonic-assisted method, and identified by (SEM), (EDS), (TEM), and (XRD) techniques. This study was performed to examine the effect of various operating parameters on photocatalytic degradation of Rhodamine B (Rh.B) over (r)GO/TiO2 embedded HCP followed by an optimization study using response surface methodology (RSM) based on Box–Behnken design (BBD). The photocatalytic activity of rGO/TiO2/polycalix[4]resorcinarene ((r)GTP) was evaluated using the cationic dye Rhodamine B as a pollutant model under solar light (intensity = 850 W/m2) between 10 and 12 am, June, Ahvaz, Iran. Response Surface Methodology was adopted for the optimization of degradation parameters viz pH, dye concentration, and nanocomposites dosage and contact time. The optimum values for the maximum Rhodamine B (Rh B) degradation of rGO/TiO2/polycalix (rGTP) and GTP were obtained, in which the degradation of rGTP was 100% and the degradation efficiency of GO/TiO2/polycalix (GTP) was 70%. ANOVA analysis results demonstrated that irradiation time and nanocomposite mass were the most significant parameters. It was found that rGO/TiO2/polycalix[4]resorcinarene (rGTP) nanocomposite displayed the best degradation yield for the dye. The results showed that the rGTP nanocomposite displayed good EIS and CV properties besides being eco-friendly and reusable. It could also show a high capacity for the elimination of the dye in the industrial wastewaters.Graphical Abstract
... expansion of industries that lack low-cost high efficiency water treatment technologies to treat the wastewater resulting in a discharge of micropollutants and contaminants into the natural water cycle. 5,6 Depending on the industry, a diverse group of organic compounds can be found, including organic dyes, organic cyanides, heterocyclic compounds, and polycyclic aromatic hydrocarbons that are characterized by high toxicity and high-enough concentrations to be considered an environmental hazard. 7 A vast amount of water is also produced during oil and gas recovery, where the discharge water makes up the largest volume waste stream. ...
Pickering emulsions have recently emerged as versatile systems capable of targeting many applications of wastewater treatment. The unique properties, which include high emulsion stability, easy preparation, low toxicity, and stimuli-responsiveness, pave the way for advances in common pollutant control processes. This review aims to provide a comprehensive overview on different aspects in the Pickering emulsion design focusing on the key structural relations and their implications in specific applications. The first section is dedicated to the critical parameters governing the Pickering emulsion type, droplet size and stability. Furthermore, a section describing methods for demulsification and particle recovery is included, in which various stimuli have been explored. Finally, the most potent applications of Pickering emulsions such as photocatalytic degradation, adsorption, extraction, and separation of common wastewater pollutants are presented and discussed with a great deal of attention towards the efficacy, current limitations, and future potential. Recognizing the rise of innovative Pickering emulsion solutions is expected to induce profound effects facilitating the technology transfer to industrial processes.
... Viruses and other pathogens are biological contaminants of special attention, as these can lead to disease outbreaks and are a public health priority (Boone et al. 2019;Furlong et al. 2017;Glassmeyer et al. 2017). These can be removed by advanced treatment technologies (Wintgens et al. 2008;Snyder et al. 2007). In San Diego (California, USA), the monitoring program proved the effectiveness of reverse osmosis (RO) to remove metals and other inorganic compounds, as well as other pharmaceutical products present in sewage (Rodríguez et al. 2009(Rodríguez et al. , 1180. ...
Sewage management is a key issue within circular economy and climate change scenario. Ensuring water supply is a challenge on a global scale. Numerous projects for potable water reuse (indirect or direct) are carried out in different parts of the world. This territorial study analyzes the situation of sewage in the Campo de Cartagena – Mar Menor region (Southeastern Spain), an area with semi-arid Mediterranean climate with structural scarcity of water and high competition for the uses of water. With data provided by ESAMUR, the evolution of its performance, use of reclaimed water and the presence of pollutants at the entrance and exit of the STPs are examined. It concludes that the concentrations of parameters contemplated in Directive 91/271/EEC are met regardless of the greater or lesser presence in the inlet flow. It is convenient to advance with potable reuse pilot projects and greater investments.
... With the advent of more modern and advanced technologies, it has become possible to detect chemical compounds at very low concentrations. These compounds were previously hidden and invisible to former methods of analysis in water bodies such as ponds, lakes, rivers, underground waters, muds, or even wastewaters [1,2]. Considering that not only human lives, but also a vast majority of Earth's fauna and flora, rely deeply on the central and invaluable role that fresh and clean water plays, it is undoubtedly and alarmingly necessary to strive and succeed in finding novel ways to detect, monitor and conceivably remove these substances from water bodies. ...
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The effect of the applied voltage on impedance spectra, measured on sensors based on solid supports with interdigitated electrodes (IDE) that are either covered or not with a layer-by-layer film prepared with polyethylenimine and poly (sodium 4-styrenesulfonate), was analyzed to detect 17α-ethinylestradiol(EE2) in mineral water and tap water. The results show that the sensor response is strongly affected by the applied voltage, the presence of film, and the water matrix, meaning that electrochemical reactions develop near the IDE. However, for low values of applied voltage, the sensor response is reproducible with negligible electrochemical reactions, allowing us to conclude that 25 mV is the appropriate voltage.
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Background The synthesis of Fe 2 O 3 /ZnO nanocomposites has gained wide acceptance in recent years due to its magnetic, photoluminescence and catalytic properties, and as an active element in gas sensors. This type of composite particle has potential biological and biomedical applications such as the detection of cancer cells, bacteria and viruses, and for magnetic separation. Objective In the present study, first we synthesized the Fe 2 O 3 /ZnO nanoparticles, and then the structural, optical and surface morphological properties were investigated by XRD, HRTEM, FESEM, XRF and FTIR analyses. Methods Fe 2 O 3 -ZnO nanoparticles were fabricated by a solgel synthesis method by combining iron chloride hexahydrate and zinc sulfate heptahydrate. In the beginning, 2g of Polyvinylpyrrolidone (PVP) stabilizer was dissolved in 100 mL deionized water and then 5 g FeCl3 was added to the solution with stirring at room temperature. Then 5g of ZnSO4 was added to the solution and synthesis temperature was increased to 100 °C. The product was evaporated for 3 hours, cooled to room temperature and finally calcined at 600 °C for 3 hours. Result The XRD results showed single-phase Fe 2 O 3 -ZnO nanocomposites with a hexagonal wurtzite structure of ZnO and spinel phase of rhombohedral α-Fe 2 O 3 . The crystallite size of as-prepared sample was determined at about 45 nm and annealed one was calculated around 40 nm. The SEM images showed that the Fe-Zn nanoparticles changed from spherical shape to rod shape by increasing the temperature after annealing. The TEM studies showed the core-shell nanoparticles with a mean diameter of 47 nm. The sharp peaks in the FTIR spectrum determined the stretching vibrations of Fe and Zn groups in the frequencies of 620, 565 cm ⁻¹ and 410 cm ⁻¹ . Conclusion The XRD data indicates a single-phase Fe 2 O 3 -ZnO structure. The SEM images show that the nanoparticles changed from sphere-like shape to rod-like shape by increasing the annealing temperature. TEM image exhibits the core-shell Fe-Zn nanoparticles with an average diameter of about 37 nm. From the FTIR data, it is shown that the presence of Fe-Zn stretching mode and the intensity of the peaks increased by increasing the annealing temperature. XRF analysis showed peaks of iron and ferrite elements, and an increase in the Zn weight percent was observed from 26.35 %Wt. to 49.26 %Wt. with increasing temperature.
Photocatalysis is a novel approach with enormous potential to degrade environmental contaminants to treat wastewater, but fewer attempts were made in studying the applicability to decompose complex wastewaters in terms of carbon disposal. A complicated pathway is involved in photochemical reactions which is affected by various factors in wastewater like residual compounds. Further analysis is also important to study the implementation of photochemical processes in diverse wastewater. Ultra violet/titanium dioxide, ultra violet light/hydrogen peroxide, ultra violet/titanium dioxide/hydrogen peroxide and ultra violet/ titanium dioxide/hydrogen peroxide/iron 3+ processes can be used to treat effluents from industries with initiation of high‐throughput techniques.
Providing clean and potable water for human use is a great challenge of the twenty-first century. Globally, water supply wrestles to keep flow with the rapidly increasing demand which is aggravated by global climate change, increasing population and drop-down in water quality. Hence, to enable integrated water management, the need for technological innovation cannot be exaggerated. Nanotechnology shows high potential in improving water and wastewater treatment efficiencies as well as enhancement of water supply by safeguarding unconventional water sources. Therefore, next generation water supply systems can be the result of leapfrogging opportunities provided by advancement in nanotechnology. The sustainability of our current water treatment, their distribution and discharge system are no longer viable due to their dependency on conveyance and centralized systems. The provided review accounts for nanotechnology enabled water treatment solutions through various multifunctional nanomaterials capable of transforming the current water treatment systems. High surface area, tunable pore size, optical, catalytic and magnetic properties, antimicrobial activity and surface chemistry are some of the magnificent properties of nanomaterials which make them a potential candidate for multiple applications. These properties of nanomaterials are applicable in water treatment as adsorbents, sensors for water quality monitoring, disinfection and for preparation of high quality nanomembranes. More importantly, the highly efficient, flexible and multifunctional materials enabled by nanotechnology provide a promising route both to retrofit aging infrastructure and to develop high performance, low maintenance decentralized treatment systems including point-of-use devices.
Chiral organic pollutants including pharmaceuticals, pesticides, herbicides, flame retardants, and polycyclic musk cause significant risks to both the environment and human health. Chiral pharmaceuticals (CPs) are among the significant class of pseudo‐persistent substances that have been observed in the concentration level from nanomolar to micromolar quantities and cause bad impacts on nontargeted species and direct or indirect human health issues due to water and foodborne contamination. The CPs may contain one or more chiral centers in their structural framework and thus enantiomers of CPs often possess different distribution, fate, bioaccumulation potential, and toxicity. The enantioselective chromatographic techniques have been extensively applied to detect drug enantiomers during the last few years. Bioremediation techniques offer unique characteristics above conventional remediation procedures as these could be cost‐effective and accomplish total organic pollutant decomposition without causing collateral damage to the site material or native flora and fauna. This review describes the impacts of chiral pharmaceuticals on the environment; detection technologies (particularly liquid chromatography), and important remedial measures for safer disposal of such pollutants. Chiral pharmaceuticals (CPs) are the pseudo‐persistent substances that have been observed in the concentration level from nanomolar to micromolar quantities in wastewater. The enantioselective chromatographic techniques have been extensively applied to detect drug enantiomers during the last few years. Bioremediation techniques offer unique characteristics above conventional remediation procedures as these could be cost‐effective and accomplish total organic pollutant decomposition without causing collateral damage to the site material or native flora and fauna.
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Water reclamation implementation and management practices at municipal wastewater treatment plants throughout the world are reviewed and some implementation and operational issues are defined. The information is based on a conventional literature survey, on an in depth survey study of European, Israeli and Australian medium and large-scale water reclamation utilities and on the findings of a dedicated international workshop. The review identified over 3,300 water reclamation projects and designed the map of the main process technologies and their fields of product water application. The main conclusion of the enquiry is that the technological risks no longer represent a major concern for the development of water reclamation projects, rather issues such as the financing, failure management and social acceptance have become more critical.
Membranverfahren werden in den Ingenieur- und Naturwissenschaften unter anderem in der Medizin-, Wasser- und Lebensmitteltechnik als Alternative zu konventionellen Verfahrensstrategien eingesetzt. Aufgrund der wachsenden Anforderungen an Prozesse in der Umwelttechnik und in der chemischen Industrie zählen Membranverfahren zu den Schlüsseltechnologien des 21. Jahrhunderts. Die zum Grundverständnis von Membranprozessen erforderlichen Zusammenhänge werden in diesem Lehrbuch und Nachschlagewerk erörtert. Ausgehend von klar dargestellten Grundlagen werden die Werkzeuge und Methoden zur Auslegung von Membranverfahren erarbeitet und anhand von Beispielen dargestellt. Des Weiteren wird der Stand der Technik sowie das Entwicklungspotential der einzelnen Verfahren vorgestellt. Die dritte Auflage dieses Buches wurde um das Kapitel "Membranreaktoren" erweitert, welches einen Einblick in die Einsatzmöglichkeiten von Membranprozessen in der Reaktionstechnik liefert. Darüber hinaus wurde das Kapitel "Ultrafiltration und Mikrofiltration" um Anwendungsbeispiele aus der Trinkwasseraufbereitung und Abwasserbehandlung erweitert. Die übrigen Kapitel wurden aktualisiert und gegebenenfalls um einige Passagen ergänzt.
The developments made in the field of pharmaceuticals, hormones and fragrances in treated wastewaters, rivers and streams are discussed. Pharmaceuticals and personal care products (PCCP) are present in the water treatment plant effluents, because they are either partially removed or not at all removed. Ozonation is one of the method to eliminate these PCCPs by undertaking a broad upgrading of municipal waters, the risks associated with current effluent quality and then required risk reduction for upgraded works. Ozonation and membrane filtration reduces the emission of pathogens from treatment works into receiving waters. It is possible to define a combination of conventional and advanced treatment technologies to effectively remove PCCPs and microorganisms, that would create a multiple barrier system.
The observed concentrations of pharmaceuticals and personal care products (PPCPs) in raw wastewater confirm that municipal wastewater represents the main disposal pathway for the PPCPs consumed in households, hospitals and industry. In sewage treatment plant effluents most PPCPs are still present, since many of these polar and persistent compounds are being removed only partially or, in some cases, not at all. Treated wastewater therefore represents an important point source for PPCPs into the environment. After passing a sewage treatment plant the treated wastewater is mostly discharged into rivers and streams or sometimes used to irrigate fields. If drinking water is produced using resources containing a substantial proportion of treated wastewater (e.g. from river water downstream of communities) the water cycle is closed and indirect potable reuse occurs. Human Pharmaceuticals, Hormones and Fragrances provides an overview of the occurrence, analytics, removal and environmental risk of pharmaceuticals and personal care products in wastewater, surface water and drinking water. The book covers all aspects of the fate and removal of PPCPs in the whole water cycle: consumption and occurrence, analytical methods, the legal background, environmental risk assessment, human and animal toxicology, source control options, wastewater and drinking water treatment as well as indirect reuse. The book presents a summary of the results obtained during the EU project “Poseidon”, combined with further expert knowledge on the field, and is written at a level appropriate for professionals involved in management of water resource quality. Professionals in the field including decision makers, engineers and scientists, as well as students entering the field, will find this an invaluable source of information. This title belongs to Water Law & Policy Series ISBN: 9781843390930 (Print) ISBN: 9781780402468 (eBook)
Recent discoveries of the formation of low levels of the potent carcinogen N-nitrosodimethylamine (NDMA) during wastewater chlorination has caused concern where indirect potable water reuse is practiced. Experiments indicate that nitrosamine formation during chlorination of wastewater is consistent with a reaction scheme involving the slow formation of a hydrazine intermediate from a secondary amine and monochloramine, followed by its rapid oxidation to the corresponding N-nitrosamine. A survey of precursors indicates that secondary amines form their corresponding N-nitrosamines to the greatest extent. However, molecules containing the secondary amine as a functional group can also form the corresponding N-nitrosamine. NDMA is the predominant N-nitrosamine found in chlorinated wastewater. However, other nitrosamines are detected. These N-nitrosamines may be important if the summed risk posed by the exposure to all N-nitrosamines is considered.