key: cord-0866002-a5j067ce authors: Verlicchi, Paola title: Trends, new insights and perspectives in the treatment of hospital effluents date: 2020-10-19 journal: Curr Opin Environ Sci Health DOI: 10.1016/j.coesh.2020.10.005 sha: 8cc19b5d4c63e63d225a6a60a601747655b3ccf7 doc_id: 866002 cord_uid: a5j067ce Recently, investigations of hospital effluent management and treatment have not only interested research groups with acquired experience in the field but have also attracted the interest of new groups over the world. The most recent literature provides new insights into the occurrence of pharmaceuticals and other contaminants of emerging concern, pathogens, viruses, antibiotic resistant bacteria and genes in hospital effluent in various new developing and developed countries. It also provides information on the effective removal of key compounds (mainly antibiotics, analgesics, beta-blockers and chemotherapy drugs) by means of enhanced biological treatments and advanced oxidation processes. The current debate among the scientific community is mainly about the proper treatment to reduce the spread of antibiotic resistant bacteria and genes, and about the feasibility (from a technical and economic point of view) of treatment trains tested at lab and pilot scale. The management and treatment of hospital effluent are issues of current concern in an increasing number of 24 countries worldwide. At the same time, the increasingly widespread awareness that the effluent produced in 25 healthcare structures may contain conventional pollutants and micro-pollutants -due to the different 26 activities occurring within the structure (diagnosis, laboratories, clinics, surgeries, medications and presence 27 of patients in different types of wards) -has led to discussion on how to improve the management and 28 enhance the treatment of such effluent. A snapshot of the current situation is provided in a recently-conventional contaminants (the so-called macropollutants) and contaminants of emerging concern (CECs) 48 (mainly pharmaceuticals) in hospital effluent, including antibiotic resistance genes and bacteria (among them 49 (18), (19) . More recently, the efficacy of pathogen and virus removal was at the centre of many debates and 50 studies, and efforts were made to evaluate whether (further) measures should be adopted, and if so which, 51 to reduce the risk of environmental contamination and to guarantee a higher level of hygienisation in the 52 hospital effluent treatment (20), (17) . Many studies aimed to improve the removal of key CECs by means of 53 enhanced biological treatments or by combining biological, chemical and physical technologies. Some investigations aimed to better understand the removal mechanisms of key compounds and their 55 interactions with the treatment environment. This is the case of the investigations by (21) countries where studies or investigations on hospital effluent have also been carried out, but also in new 66 ones, such as Ethiopia (25), Columbia (5), India (26), Iran (27), (28), Costa Rica (29) and Thailand (21). This contact time of 12.8 min. The poor removal of DOC during ozonation showed that any remaining 79 recalcitrant compounds were not completely removed or mineralised and could produce transformation 80 products requiring further investigations, as suggested by (31). 81 Interesting results have been achieved in the removal of a selection of antibiotics with the system tested by 82 (32) consisting of an enhanced MBR (equipped with hallow fibre membranes) coupled with ozonation. The 83 MBR system is that originally proposed by (33) and then investigated by (34) for the effluent of Trung 84 Vuong Hospital in Vietnam. Its novelty consists of the presence of polyester-urethane sponge media with 85 high porosity in its aerobic compartment in order to promote micropollutant removal and at the same time 86 reduce membrane fouling, which is still the most critical operational factor for this biological system. It 87 operated with a biomass concentration of around 5,000 mg/L, a ratio between volatile and total suspended 88 solids of 0.79, and a sludge retention time of 20 days. 89 MBRs coupled with granular or powder activated carbons (GAC or PAC), or characterised by modified 91 membranes, or operating under specific and controlled conditions. The Spanish group at the University of 92 Santiago of Compostela (35) applied their patented system SemPAC© to hospital effluent and evaluated its 93 performance with regard to 5 CECs: ibuprofen, 17α-ethynylestradiol, diclofenac, carbamazepine, and 94 trimethroprim. It consists of a sequential batch reactor followed by an external submerged microfiltration 95 membrane tank where PAC is added to enhance the sorption of residues of CECs. They found that the 96 addition of PAC improves the removal of all the compounds, including the most recalcitrant carbamazepine 97 and trimethoprim. The results also showed that it is important to identify when PAC must be added due to 98 powder saturation in order to guarantee a constant removal of all the key compounds (every 20 days in 99 their investigation). 100 Promising results have been obtained with moving bed biofilm reactors (MBBR) for the removal of specific 101 pollutants such as anionic detergents as in the study by (36) regarding effluent from an Iranian hospital 102 (removal achieved around 92 % of LAS with a filling rate of 70 % of Kaldness carriers, a biomass effluent. They found that the chemical (radical attacks) and physical (suspended solids disaggregation) 115 effects due to the sonochemical step improved the removal of the recalcitrant compounds showing a 116 pondered average removal of around 59 %. The reduction of the pharmaceutical load increased up to 83 % 117 when Fe 2+ (5 ppm) and UVC light (4 W) were added to the sonochemical system, thus generating a sono-118 photo-Fenton process. The study showed the promising results that can be achieved by these treatment 119 trains but also the high energy costs: if future research is able to reduce them, this solution could become 120 economically feasible. 121 Electrochemical technologies have also been tested for the degradation and mineralisation of specific 122 compounds occurring in hospital effluent. In this context, (40) investigated the degradation of the 123 chemotherapy drug doxorubicin (which could reach concentrations as high as 1 µg/L) by nanostructured 124 graphite electrodes with metallic oxides (grphite, TiO 2 @graphite and AuO-TiO 2 @graphite electrodes). The 125 lab scale experiments showed complete degradation with the AuO-TiO2@graphite electrode and no 126 undesired compound was formed. As to ecotoxicological effects, the tested treatment did not cause any 127 effect on embryo-larval development of zebrafish, but DNA damage was observed after 96 hours' 128 exposure. 129 130 tank, the chemical disinfection of raw hospital effluent by means of high doses of sodium hypochlorite (up 149 to 800 g/m 3 ) is not sufficient to remove SARS-CoV-2 viral RNA. The authors highlight that the current 150 recommended doses by the World Health Organization (free chlorine ≥0.5 mg/L for at least 30 min) and 151 China Centers for Disease Control and Prevention (free chlorine above 6.5 mg/L after 1.5-h contact) are not 152 sufficient to reduce the content of the virus in hospital effluent. Overdoses of the disinfectant seem to be 153 able to remove the virus but they lead to significant concentrations of disinfectant by-products. 154 Suggestions provided by (15), (16), (17) suggest the importance of the proper management of waste and 155 wastewater within a hospital, which becomes absolutely necessary during a public health emergency. 156 157 The debate on the most suitable treatment of hospital effluent is ongoing and constantly fed by new 159 insights. It allows to identify the fields that require urgent research and recommendations for a suatainable 160 hospital effluent management and treatment. The COVID-19 pandemic has highlighted the need for further 161 investigations into how to reduce the risk of spreading Coronaviruses and, more generally, that the 162 reduction of ARG, ARB and pathogens should be among priority research areas to preserve and protect the 163 water environment, improve sanitation, and guarantee clean and safe water for a wide range of activities, 164 in accordance with the United Nations Sustainable Development Goals 165 SARS-CoV-2 from faeces to 221 wastewater treatment: What do we know? A review Hospital effluent: A reservoir for 224 carbapenemase-producing Enterobacterales? Sci Total Environ Antibiotic resistance in urban and 227 hospital wastewaters and their impact on a receiving freshwater ecosystem Evaluation of Factors Influencing the 230 Environmental Spread of Pathogens by Wastewater Treatment Plants Removal and 233 monitoring acetaminophen-contaminated hospital wastewater by vertical flow constructed wetland 234 and peroxidase enzymes Ozonation of nursing home wastewater pretreated in a membrane 237 bioreactor High rate treatment of 257 hospital wastewater using activated sludge process induced by high-frequency ultrasound Occurrence of pharmaceuticals, hazard assessment and ecotoxicological 262 evaluation of wastewater treatment plants in Costa Rica The impact of on-site 264 hospital wastewater treatment on the downstream communal wastewater system in terms of 265 antibiotics and antibiotic resistance genes Evaluation of a full-scale 268 wastewater treatment plant upgraded with ozonation and biological post-treatments: Abatement of 269 micropollutants, formation of transformation products and oxidation by-products Hospital wastewater treatment by 272 sponge membrane bioreactor coupled with ozonation process Evaluation of a novel sponge-submerged membrane bioreactor (SSMBR) Removal of 288 pharmaceuticals, toxicity and natural fluorescence through the ozonation of biologically-treated 289 hospital wastewater, with further polishing via a suspended biofilm Fungal 292 treatment of metoprolol and its recalcitrant metabolite metoprolol acid in hospital wastewater Biotransformation, sorption and ecotoxicological impact Effective elimination of fifteen relevant pharmaceuticals in hospital wastewater from Colombia by 296 combination of a biological system with a sonochemical process Ecotoxicological assessment 299 and electrochemical remediation of doxorubicin Screening of Metal and Antibiotic Resistance in Beta-lactamase 302 304 42. WHO. Global priority list of antibiotic-resistant batceria to guide research, discovery, and 305 development of new antibiotics The prevalence and characterization of extended-309 spectrum β-lactamase-and carbapenemase-producing bacteria from hospital sewage