Review articleA review on hospital wastewater treatment: A special emphasis on occurrence and removal of pharmaceutically active compounds, resistant microorganisms, and SARS-CoV-2
Graphical Abstract
Introduction
Hospitals play a pivotal role in the well-being of humanity and facilitate research in the field of medical advancement. They help in complementing various parts of the health system and provide continuous services to tackle the complex health conditions of human beings [1]. The healthcare sector is one of the largest employers in the United States (US), with more than six million people employed at US hospitals with around 36.3 million admissions in 2018 [2]. The worth of the Indian health sector has been projected to jump from 140 billion U.S. dollars in the year 2016 to 372 billion dollars by the year 2022 [3]. With the onset of the COVID-19 pandemic, hospitals and other health care facilities have been responsible for giving a chance for survival to more than 20 million people affected by the SARS-CoV-2 virus. Concerning the ever-growing expansion of medication and health care activities in the hospital, the generation of large quantities of wastewater and its management is an impounding challenge in environmental engineering [1]. On average, hospitals in developed countries generate a significantly higher volume of wastewater as compared to hospitals in developing countries [1], [4], [5], [6], [7], [8].
Hospital wastewater (HWW) is also characterized by the presence of various emerging contaminants, such as pharmaceutically active compounds (PhACs), several microorganisms including antibiotic-resistant bacteria (ARB), antibiotic-resistant genes (ARG), persistent viruses, etc. [9], [10], [11], [12]. Generally, HWW comprises high biochemical oxygen demand (BOD), chemical oxygen demand (COD), ammonia, and nitrogen content, and their concentration is higher compared to the domestic wastewater [13], [14]. BOD is the amount of oxygen consumed by microorganisms to decompose organic matter under aerobic conditions at a specific temperature and duration of time, while COD is the amount of oxygen equivalents consumed in the chemical oxidation of organic matter by a strong oxidant [15], [16]. Hence BOD can be referred to as the biodegradable fraction of wastewater, while COD is the measure of both biodegradable and non-biodegradable organic compounds. The ratio of BOD and COD of wastewater is referred to as the biodegradability index [16], [17]. The biodegradability index of HWW is also lower than the municipal wastewater, making them difficult to treat by conventional biological systems [13], [14], [18]. Many of the recalcitrant organic compounds present in HWW, such as PhACs, are highly toxic with very low drinking water equivalent limit (DWEL) values making them a considerable threat to the environment [19]. Viruses, ARB, and ARG continue to survive even after the treatment of HWW, and their release to the aquatic ecosystem imposes a significant threat to the environment [6], [20].
Over the years, various treatment technologies, including the biological methods, such as activated sludge process (ASP), membrane bioreactor (MBR), moving bed bioreactor (MBBR), constructed wetlands (CWs), the advanced oxidation processes, such as photocatalysis, Fenton process, etc. have been implemented to treat HWW [8], [13], [21], [22]. Many lab-based studies targeting the removal of PhACs and other recalcitrant contaminants present in HWW are reported in several works of literature, but only a handful number of pilot-scale and full-scale studies have been conducted addressing their treatment concerning HWW [8], [19], [23]. Treatment of HWW is not an easy feat, considering the vast quantities of wastewater generated having high COD, nitrogen, and PhAC content. Furthermore, the onset of COVID-19 pandemic has shifted the focus to the removal of viruses, ARG, ARB present in HWW, and this area has not been substantially addressed. Given the necessity and recent emergence of this profound health and environmental concern, the present review stems from the unavailability of comprehensive documentation in this area.
In this review, a thorough characterization of HWW has been conducted considering the variation of the characteristics of HWW in different regions. A detailed insight has been provided on the occurrence of PhACs, viruses, and several microorganisms in various HWW. A special emphasis has been given to the presence of SARS-CoV-2 and SARS-CoV in wastewater, keeping in mVerlicchiind the COVID-19 pandemic scenario. In recent years, various reviews were published on the characterization of hospital wastewater and their treatment. Khan et al. [24] reviewed the occurrence of pharmaceuticals in HWW and the performance of primary, secondary, and tertiary treatment techniques for their removal. Orias and Perrodin [25] reviewed the characteristics of hospital wastewater and its eco-toxicity. Verlicchi et al. [26] also summarized the characteristics of hospital wastewater and their treatment using conventional and advanced processes. However, most of these studies cover lab-based technologies that are still in developing stages. Performance of pilot/full-scale treatment units dedicated to the simultaneous removal of recalcitrant organic compounds, physicochemical parameters, such as BOD, COD, total suspended solids (TSS), ammonia nitrogen, total nitrogen, pathogens, etc. from HWW has not been sufficiently addressed. This review primarily focuses on the performance of various operational pilot-scale and full-scale treatment units by various biological and advanced oxidation treatment technologies dedicated to the treatment of HWW. The performance of these treatment units in terms of removal of BOD, COD, ammonia nitrogen, TSS, and PhACs has been extensively discussed. The inactivation of persistent ARG, ARB, and virus are also critically analyzed. Furthermore, the various emerging technologies to combat PhACs, ARB, ARG, such as photocatalysis, anodic oxidation, Fenton-based processes, and treatment using nanoparticles have also been discussed. A special emphasis is provided on the occurrence and removal of SARS-CoV-2 and SARS-CoV to catalyze the research on the present global need.
Section snippets
Water consumption and effluent generation from hospitals
Hospitals around the globe require large amounts of water for their proper functioning for various health care facilities. HWW, among all other healthcare waste, imposes a grave hazard to human health and the environment because of their capability to enter watersheds, pollute surface and groundwater, when inappropriately handled and disposed to hydrosphere [27]. According to the World health organization (WHO) guidelines for the proper functioning of healthcare facilities, 40–60 L/day of water
Characteristics of hospital wastewater
The effluent coming out of different hospitals are rich in PhACs, microorganisms, and are characterized by high COD, BOD, ammonia, nitrate, total nitrogen (TN), TSS, total organic carbon (TOC), total Kjeldahl Nitrogen (TKN), etc. Qualitative analysis of medical waste of 10 hospitals in Iran indicated that liquid waste had a 16.70% contribution to hazardous–infectious waste [33]. The discharge from hospitals can be classified into four broad categories, i.e., blackwater, greywater, stormwater,
Removal of BOD, COD, TSS, nitrogen, and PhACs
Over the past two decades, various treatment processes have been implemented and up-scaled to pilot or full-scale treatment system for treating HWW. The details of various pilot/full-scale treatment units have been mentioned in Table 2. The performance of the various pilot/full-scale treatment technologies in treating the different components of HWW has been discussed in the following sections and has been depicted in Fig. 4. A schematic representation of the source of different pollutants in
Emerging technologies for removal of PhACs and various pathogens
ARG, ARB, viruses, recalcitrant organic compounds, such as PhACs, personal care products, X-ray contrast media form an integral part of the HWW. The presence of these components makes the HWW less biodegradable, toxic, and difficult to treat [163]. Over the past decade, research has been focused on the removal of PhACs, ARG, ARB, and other recalcitrant organic compounds by various emerging technologies, such as photocatalytic degradation, photolysis, anodic oxidation, Fenton’s processes,
Challenges in HWW management
One of the major challenges in the field of HWW management is the monitoring and detection of the pollutants [199]. PhACs and other recalcitrant organic compounds are present in the HWW is the range of ng/L to μg/L, which require highly sensitive to quantify [19], [36], [169], [200], [201]. Proper detection of such contaminants in necessary to implement proper legislations for HWW management [199]. Only a few guidelines pertaining to hospital waste management, such as “Effluent Guidelines and
Summary of findings
Hospitals are significant contributors to a large amount of complex wastewater to inland surface water and municipal sewer. Furthermore, it was found that hospitals in developed countries generated much higher quantities of wastewater than developing countries. HWW comprises a wide range of contaminants, such as recalcitrant PhACs, viruses, ARG, ARB, and high nutrient content. A low biodegradability index makes the treatment of HWW more challenging. PhACs, such as diclofenac and ciprofloxacin,
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.
References (213)
- et al.
Hospital wastewater treatment scenario around the globe
- et al.
Hospital effluents management: chemical, physical, microbiological risks and legislation in different countries
J. Environ. Manag.
(2016) - et al.
Quantification and molecular characterization of enteric viruses detected in effluents from two hospital wastewater treatment plants
Water Res.
(2011) - et al.
Insights into the relationship between antimicrobial residues and bacterial populations ina hospital-urban wastewater treatment plant system
Water Res.
(2014) - et al.
Surveillance of antimicrobial resistance among Escherichia coli in wastewater in Stockholm during 1 year: Does it reflect the resistance trends in the society?
Int. J. Antimicrob. Agents.
(2015) - et al.
Antibiotic resistant bacteria removal of subsurface flow constructed wetlands from hospital wastewater
J. Environ. Chem. Eng.
(2018) - et al.
What have we learned from worldwide experiences on the management and treatment of hospital effluent? − an overview and a discussion on perspectives
Sci. Total Environ.
(2015) - et al.
Characteristics of water quality of municipal wastewater treatment plants in China: implications for resources utilization and management
J. Clean. Prod.
(2016) - et al.
Pharmaceutically active compounds in aqueous environment: a status, toxicity and insights of remediation
Environ. Res.
(2019) Drugs in the environment: emission of drugs, diagnostic aids and disinfectants into wastewater by hospitals in relation to other sources − a review
Chemosphere.
(2001)
Hospital effluent: investigation of the concentrations and distribution of pharmaceuticals and environmental risk assessment
Sci. Total Environ.
Occurrence, sources and conventional treatment techniques for various antibiotics present in hospital wastewaters: a critical review
TrAC Trends Anal. Chem.
Characterisation of the ecotoxicity of hospital effluents: a review
Sci. Total Environ.
Hospital effluents as a source of emerging pollutants: an overview of micropollutants and sustainable treatment options
J. Hydrol.
Groundwater contamination by microbiological and chemical substances released from hospital wastewater: health risk assessment for drinking water consumers
Environ. Int.
Application of MBR for hospital wastewater treatment in China
Desalination.
Characterization of medical waste from hospitals in Tabriz, Iran
Sci. Total Environ.
Characterization of pharmaceuticals and personal care products in hospital effluent and waste water influent/effluent by direct-injection LC-MS-MS
Sci. Total Environ.
Effective adsorption of non-biodegradable pharmaceuticals from hospital wastewater with different carbon materials
Chem. Eng. J.
The status of industrial and municipal effluent treatment with membrane bioreactor technology
Chem. Eng. J.
Degradation of β-blockers in hospital wastewater by means of ozonation and Fe2+/ozonation
Water Res.
Application of advanced oxidation processes followed by different treatment technologies for hospital wastewater treatment
J. Clean. Prod.
Horizontal sub surface flow Constructed Wetlands coupled with tubesettler for hospital wastewater treatment
J. Environ. Manag.
Pre-treatment of hospital wastewater by coagulation-flocculation and flotation
Bioresour. Technol.
Physico-chemical, microbiological and ecotoxicological evaluation of a septic tank/Fenton reaction combination for the treatment of hospital wastewaters
Ecotoxicol. Environ. Saf.
Evaluation of biodegradability and oxidation degree of hospital wastewater using photo-Fenton process as the pretreatment method
J. Hazard. Mater.
Nanofiltration performances after membrane bioreactor for hospital wastewater treatment: fouling mechanisms and the quantitative link between stable fluxes and the water matrix
Water Res.
The occurrence of pharmaceuticals, personal care products, endocrine disruptors and illicit drugs in surface water in South Wales, UK
Water Res.
Occurrence patterns of pharmaceutical residues in wastewater, surface water and groundwater of Nairobi and Kisumu city, Kenya
Chemosphere.
A review of the occurrence of pharmaceuticals and personal care products in Indian water bodies
Ecotoxicol. Environ. Saf.
Determination of pharmaceutical compounds in hospital effluents and their contribution to wastewater treatment works
Environ. Int.
Removals of pharmaceutical compounds from hospital wastewater in membrane bioreactor operated under short hydraulic retention time
Chemosphere.
Contribution of hospital effluents to the load of pharmaceuticals in urban wastewaters: identification of ecologically relevant pharmaceuticals
Sci. Total Environ. 461–
Occurrence and distribution of pharmaceuticals in wastewater from households, livestock farms, hospitals and pharmaceutical manufactures
Chemosphere.
The occurrence, fate, and distribution of natural and synthetic hormones in different types of wastewater treatment plants in Iran
Chin. J. Chem. Eng.
What happens in hospitals does not stay in hospitals: antibiotic-resistant bacteria in hospital wastewater systems
J. Hosp. Infect.
Daily physicochemical, microbiological and ecotoxicological fluctuations of a hospital effluent according to technical and care activities
Sci. Total Environ.
A review of the influence of treatment strategies on antibiotic resistant bacteria and antibiotic resistance genes
Chemosphere
Vancomycin resistant enterococci: from the hospital effluent to the urban wastewater treatment plant
Sci. Total Environ.
BlaTEM and vanA as indicator genes of antibiotic resistance contamination in a hospital-urban wastewater treatment plant system
J. Glob. Antimicrob. Resist.
Fate of pathogens and viruses in hospital wastewater and their treatment methods
Reverse osmosis integrity monitoring in water reuse: the challenge to verify virus removal − a review
Water Res.
Study on the resistance of severe acute respiratory syndrome-associated coronavirus
J. Virol. Methods
Concentration and detection of SARS coronavirus in sewage from Xiao Tang Shan Hospital and the 309th Hospital
J. Virol. Methods
SARS-CoV-2 RNA in wastewater anticipated COVID-19 occurrence in a low prevalence area
Water Res.
SARS-CoV-2 RNA detection of hospital isolation wards hygiene monitoring during the Coronavirus Disease 2019 outbreak in a Chinese hospital
Int. J. Infect. Dis.
Potential spreading risks and disinfection challenges of medical wastewater by the presence of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) viral RNA in septic tanks of Fangcang Hospital
Sci. Total Environ.
First confirmed detection of SARS-CoV-2 in untreated wastewater in Australia: A proof of concept for the wastewater surveillance of COVID-19 in the community
Sci. Total Environ.
SARS-CoV-2 in wastewater: state of the knowledge and research needs
Sci. Total Environ.
First environmental surveillance for the presence of SARS-CoV-2 RNA in wastewater and river water in Japan
Sci. Total Environ.
Cited by (152)
Monitoring viruses and beta-lactam resistance genes through wastewater surveillance during a COVID-19 surge in Suwon, South Korea
2024, Science of the Total EnvironmentHospital wastewater (HWW) treatment in low- and middle-income countries: A systematic review of microbial treatment efficacy
2024, Science of the Total EnvironmentPhotocatalytic degradation of persistent antibiotic pollutants by MOF-derived bird-nest ferric molybdate
2024, Journal of Water Process EngineeringTransformation of waste into valuable materials: Utilizing waste printer powder to remove hazardous organic dye and pharmaceutical pollutants from wastewater
2024, Colloids and Surfaces A: Physicochemical and Engineering Aspects