Method for elimination of pharmaceuticals from wastewater

Abstract

Method for eliminatoin of pharmaceuticals from wastewater by biological, photo-oxidation and sorption means consists of eliminating the pharmaceuticals from 5000 parts by weight of water at 25 °C by biologically eliminating the pharmaceuticals by adding 300 to 800 parts by weight of a filling containing Pseudomonas fluorescens bacteria encapsulated in polyvinyl alcohol lenses. The resulting mixture is maintained in buoyancy by agitation for 24 to 500 hours, then biologically pretreated water is homogenized for 3 to 7 minutes. Then the pharmaceuticals are eliminated by photooxidation for 5 to 60 minutes by UV radiation with a relative radiant power of 50 W / L of treated water from and the addition of 0.4 to 0.6 parts by weight of 30% H2O2and then by sorption by adding 45 to 55 parts by weight of a sorbent, which is iron humate or zinc humate, and applying it with agitation for 30 to 240 minutes.

Description

[0001] Method for elimination of pharmaceuticals from wastewater

[0002] Technical field

[0003] The invention relates to a method for the elimination of pharmaceuticals from wastewater using a combination of biological, photooxidation and sorption water treatment methods.

[0004] Background art

[0005] Various methods for eliminating pharmaceuticals from water are known from the background art, mainly biological, ozonation, photo-oxidation, sorption, filtration or methods using electric or electromagnetic fields.

[0006] Most wastewater treatment plants are based on a combination of mechanical treatment (the so- called primary stage) and biological treatment using activated sludge (the secondary stage). For the treatment of water before discharge into a receiving watercourse, it is possible to include a so-called tertiary stage, but this is not nearly as widespread, among other things because the spectrum of obligatorily monitored substances from the category of pharmaceuticals in treated water is only defined in a very limited way by legislation. The background art is thus lagging behind scientific knowledge, as a number of substances are known that are not subject to obligatory monitoring but have the potential to negatively affect the environment and human health. These include, for example, certain pesticides, substances affecting hormonal systems (endocrine disrupting compounds), emerging pollutants of concern, and human and veterinary pharmaceuticals, their residues and degradation products. In the field of pharmaceuticals and their residues, only Commission Implementing Decision (EU) 2018 / 840 of 5 June 2018 exists in the EU, which defines only 17-alpha-ethinylestradiol (EE2), 17-beta-estradiol (E2), estrone (El), macrolide antibiotics, amoxicillin and ciprofloxacin as pollutants of concern.

[0007] The effectiveness of elimination of pharmaceuticals from wastewater in conventional municipal treatment plants varies greatly from one substance to another , ranging from almost complete elimination to almost zero efficiency. (https: / / doi.Org / 10.1016 / j.jwpe.2021.102098, https: / / doi.Org / 10.1016 / j.scitotenv.2017.04.102, Table 2a). This is due to the spectrum of chemical structures of pharmaceuticals causing variability in properties, including sorbability, oxidisability or biodegradability. Due to this fact, some of these emerging pollutants are also discharged into the receiving water.

[0008] From the background art, mainly complementary biological methods are known for the elimination of pharmaceuticals from wastewater in the tertiary stage using specifically selected and pre-cultivated microorganisms (i.e. not naturally occurring as in activated sludge), as well as oxidation processes including photo-oxidation and sorption onto suitable materials.

[0009] From the state of the art, there are also known methods for the elimination of pharmaceuticals and their residues from wastewater by a combination of advanced oxidation processes (AOPs) and biodegradation, which are based on the oxidative degradation of micropollutants, followed by adsorption and membrane filtration.

[0010] Adsorption is a reliable and cost-effective method for eliminating pollutants including low concentration pharmaceuticals from wastewater (activated carbon, lignin, zeolites, etc.).

[0011] One of the existing biological methods for eliminating pharmaceuticals from wastewater uses encapsulated bacteria in polyvinyl alcohol lenses. Also referred to as the encapsulation method (US5089407A, CA2221111A1). However, the key parameter of elimination efficiency is not the method of encapsulation, but the metabolic potential of the microorganism used. The disadvantage of these solutions is the use of microorganisms that are not efficient enough to eliminate pharmaceuticals.

[0012] One of the existing photooxidation methods for eliminating pharmaceuticals from wastewater uses a combination of ultraviolet radiation (hereafter referred to as "UV radiation"), an oxidizing agent with a catalytic effect (e.g. H2O2) and possibly catalysts for the oxidative decomposition of organic pollutants. (CN 113716675A). The disadvantage of this invention is that it uses a high power lamp (1000 W) and long retention times (2 to 5 hours) and thus has a high power consumption. Of the organic micropollutants, only the elimination efficiency of nitrophenols is reported; pharmaceuticals have not been tested.

[0013] One of the existing sorption methods for the elimination of pharmaceuticals from wastewater uses sorbents such as metal humates, mainly iron humate has been used for the sorption of chlorpromazine (Ansone-Bertina et al. 2021, DOI.org / 10.3390 / appl 1073021).

[0014] Ozontech offers a system based on in-situ ozone production for the oxidation of pollutants. This system eliminates, among others, some pharmaceuticals (namely hydrochlorothiazide, metoprolol, furosemide, oxazepam, carbamazepine, paracetamol, codeine or propofol). It combines ozonation with activated carbon sorption to increase elimination efficiency (https: / / mel- lifiq.com / markets / pharmaceutical-industry / ) . The disadvantages of the solution are the energy consumption of ozone production, the limited number of analytes and the high cost of activated carbon as the final sorbent.

[0015] ENDETECH (ENzymatic DEcontamination TECHnology) uses enzymes catalysing the degradation (hydrolysis or oxidation) of selected substances (antibiotics, hormones and other endocrine disrupting compounds) immobilized on polymer and ceramic lenses. The technology has been tested on artificial and real waters containing these pollutants (https : / / cordis ,eu- ropa.eu / proiect / id / 282818 / reporting). The disadvantage of the solution is the relatively high specificity of the enzymes used, i.e. practically for each pollutant a different enzyme has to be used and the technology is not able to eliminate the whole spectrum of commonly occurring pharmaceuticals and residues.

[0016] The technology according to patent US20190225521A1 is designed to treat water by a combination of disinfection, filtration and purification using an electromagnetic field using at least two frequencies and pulses. The technology eliminates pharmaceuticals, namely antibiotics, pain killers, heart medications, mind-altering pharmaceuticals, contraceptives, antidepressants and sex pharmaceuticals (https: / / patents.google.com / patent / US20190225521Al / en?), among many other pollutants and unwanted microorganisms. The disadvantage of the solution is the energy consumption for ozonization and magnetic field generation, and the consumption of filters, or the production of waste in the form of used filters with reduced filtration capacity. The invention application of Eco Fuel Laboratories CZ2010518A3 describes an integrated unit comprising of a set of interconnected devices in which sequential operations are carried out, which are reductive dehalogenation in an electric field, advanced oxidation by so-called hydroxyl ions in an electric field and adsorption of these substances, in particular from contaminated water intended as a source of drinking water. In addition to other substances, the unit also eliminates some pharmaceuticals, mainly of a hormonal nature. The main disadvantage of the solution is the high power consumption. Alternatively, according to the invention, a solar panel can be used for off-grid use, but this represents a significant investment cost and is weather dependent. Another disadvantage is the need for an expensive filling containing 3 % palladium, which needs to be changed occasionally.

[0017] These shortcomings are at least partially eliminated by the method for eliminating pharmaceuticals from wastewater according to the invention.

[0018] Disclosure of invention

[0019] Method for eliminating pharmaceuticals from wastewater by biological, photooxidation and sorption method, characterized in that from 5000 parts by weight of water at 25 °C, the pharmaceuticals are first eliminated biologically by adding to it 300 to 800 parts by weight of a filling containing Pseudomonas fluorescens bacteria encapsulated in polyvinyl alcohol lenses, and the resulting mixture is maintained in a buoyant state by agitation for 24 to 500 hours, then the biologically pre-treated water is homogenised for 3 to 7 minutes, then the pharmaceuticals are eliminated by photo-oxidation for 5 to 60 minutes with UV radiation at a relative radiant power of 50 W / L of purified water with the addition of 0.4 to 0.6 parts by weight of 30% H2O2 and then eliminating the pharmaceuticals from the biologically and photo-oxidatively pretreated water by sorption by adding 45 to 55 parts by weight of at least one sorbent selected from the group consisting of zinc humate and iron humate and agitating for 30 to 240 minutes.

[0020] The method for eliminating pharmaceuticals from wastewater according to the invention comprises a targeted combination of three sub-methods, which enables a number of different pharmaceuticals and possibly their residues, many of which are chemically or biologically stable or poorly sorbed, to be eliminated from the wastewater quickly and easily. These three sub-ways include 1. biodegradation of pharmaceuticals using Pseudomonas fluorescens bacteria having the naphthalene biodegradation pathway, preferably immobilized. This step takes 24 to 500 hours under atmospheric conditions; 2. Photooxidative pharmaceutical elimination using UV light and hydrogen peroxide for 5 to 60 min at atmospheric conditions and pH biologically pretreated water; and 3. sorption of remaining pharmaceuticals to zinc humate or iron humate under atmospheric conditions for 30 to 240 min.

[0021] A method for eliminating pharmaceuticals from wastewater according to the invention comprising a combination of three sub-methods is well demonstrated by the following Table 1. It shows the concentrations of selected pharmaceuticals that occur in significant concentrations in the water after the first (mechanical) and second (biological) treatment stages of a conventional municipal wastewater treatment plant (and are therefore commonly discharged into the receiving water due to the absence of emission limits for these substances) and also shows the effectiveness of the individual partial methods for eliminating pharmaceuticals from waste water according to the invention separately with short and long retention times. The results are demonstrated per partes, i.e. the percentage efficiency of each partial method for eliminating pharmaceuticals from waste water according to the invention is always individual and the individual elimination efficiencies for each sub-method of elimination of pharmaceuticals from wastewater according to the invention cannot be added togetherT These are demonstrative of the elimination efficiencies of each of the partial methods for eliminating pharmaceuticals from waste waters according to the invention. This shows that when one particular partial method for eliminating pharmaceuticals from waste water according to the invention or the composition of contaminants in the wastewater is too diverse, the method for eliminating pharmaceuticals from wastewater according to the invention is preferred. Table 1 demonstrates how the different partial methods for eliminating pharmaceuticals from waste water according to the invention complement each other well to achieve significant elimination of various analytes. The results show that in many cases, one sub method for eliminating pharmaceuticals from wastewater according to the invention either does not eliminate the pharmaceutical at all or eliminates it only after a period of time that is practically unusable in the tertiary treatment stage. A prime example is Acridine, which is not biologically eliminated from wastewater at all, is almost not eliminated by sorption, and is only eliminated to some extent by photooxidation over time. Another example is Diclofenac, which is also not biologically eliminated from wastewater at all, is practically not eliminated by sorption, but is eliminated rapidly by photooxidation to some extent. Ibuprofen, on the other hand, is very well eliminated biologically from wastewater, although an equilibrium residue remains in the wastewater, but is not eliminated by sorption and is only eliminated by photo-oxidation over a longer period of time.

[0022] Table 1: Input concentrations of analytes in the test water and elimination efficiencies of selected pharmaceuticals by each of the partial methods of pharmaceutical elimination from wastewater according to the invention sepa- rately with short and long retention times [% w / w]

[0023] The method for eliminating pharmaceuticals from wastewater according to the invention comprises a combination of three sub-methods of water purification, namely biological, photo-oxidation and sorption, which are complementary to each other. It uses appropriately selected effective sorbents, microbial strains and the optimal technological parameters. The method for eliminating pharmaceuticals from wastewater according to the invention enables the elimination of residues of a range of pharmaceuticals at concentrations up to the detection limits of high-performance liquid chromatography.

[0024] Examples

[0025] Example 1 a) Biological part of the method for elimination of pharmaceuticals from wastewater

[0026] In example 1, wastewater that has been pre-treated in two stages, namely mechanically and biologically, at a municipal wastewater treatment plant and otherwise flows into a receiving water body, was used. Forty of the most common analytes, mainly pharmaceuticals and their residues, were analysed in this wastewater. The analysis revealed the presence of 19 of these analytes in the wastewater above the limit of detection (25 ng / L). The concentrations of these analytes ranged from 100 to 16 000 ng / L. The measured concentrations of the monitored pharmaceuticals in the influent wastewater are reported in Table 1.

[0027] The biological part of the method for eliminating pharmaceuticals from wastewater according to the invention comprises biologically eliminating pharmaceuticals from 5 litres of said wastewater at a temperature of 25 °C by adding to it 546 g of a cartridge containing the bacteria Pseudomonas fluorescens encapsulated in polyvinyl alcohol lenses which are left to act with constant agitation to maintain them in a buoyant state for 500 hours.

[0028] In this biologically treated water, seven analytes were completely eliminated, another seven were partially eliminated, and the remaining five analytes did not show a significant decrease in concentration. b) Photo-oxidation part of the method for eliminating pharmaceuticals from wastewater

[0029] 300 mL of water biologically pre-treated according to example 1(a) at 25 °C homogenised for 5 minutes. Then 0.5 mL of 30% H2O2 is added to it and at the same time it is exposed to UV radiation from a 16 W source for 1 hour.

[0030] In the water pretreated biologically according to example 1(a) and purified by photooxidation according to example 1(b), 100% elimination of one remaining analyte occurred, and the other eight analytes were partially eliminated. c) Sorption part of the method for eliminating pharmaceuticals from wastewater

[0031] To 5 litres of water pretreated biologically according to example 1(a) and photo -oxidatively according to example 1(b), 50 g of zinc humate sorbent is added at 25 °C to maintain a water to sorbent ratio of 100:1 by weight and allowed to act for 180 minutes with constant stirring.

[0032] In the water pretreated biologically according to example 1(a) and photooxidatively according to example 1(b) and treated by sorption according to example 1(c), two additional analytes were eliminated to below the limit of detection, and four additional analytes were eliminated to just above the limit of detection. Overall, in example 1, the method for eliminating pharmaceuticals from wastewater according to the invention achieved a reduction in the concentration of 18 analytes to below the limit of detection (an efficiency of nearly 100 %), with only one analyte remaining eliminated with an efficiency of less than 50 %.

[0033] Table 1: Input and output concentrations of 19 analytes (pharmaceuticals) in wastewater in each example, with elimination efficiencies in parentheses.

[0034] LOD = Limit of detection (25 ng / L); combined uncertainty of determination ± 20 %

[0035] Example 2

[0036] The method for eliminating pharmaceuticals from wastewater in example 2 is performed in the same manner as in example 1(a), (b) and (c), except that iron humate is used instead of zinc humate in the sorption part of the method for eliminating pharmaceuticals from wastewater according to paragraph (c).

[0037] The final pharmaceutical concentration after sorption on iron humate and the elimination efficiency are given by Table 2. Overall, of the 19 analytes, three were eliminated to below the limit of detection (elimination efficiencies of almost 100 %), 10 analytes were eliminated with efficiencies of 75 to 100 %, four analytes were eliminated with efficiencies of 50 to 75 %, and only one analyte was eliminated with an efficiency of 25 to 50 %.

[0038] Example 3

[0039] The method for eliminating pharmaceuticals from wastewater in example 3 is performed in the same manner as in example 1(a), except that the biological part of the method for eliminating pharmaceuticals from wastewater only allows the encapsulated bacteria to act for 24 hours.

[0040] The photo-oxidation part of the method for eliminating pharmaceuticals from wastewater is performed in the same way as in example 1(b), except that the UV treatment lasts only 5 minutes.

[0041] The sorption part of the method for eliminating pharmaceuticals from wastewater is performed in the same way as in example 1(c), except that the zinc humate is left to act for only 30 minutes. In example 3, the method for eliminating pharmaceuticals from the wastewater according to the invention achieved a lower reduction in concentration of the 19 analytes of interest than in example 1, but even so, the reduction in concentration achieved was relatively large, especially considering a relatively short time. Overall, of the 19 analytes, four were eliminated to below the limit of detection (elimination efficiencies close to 100 %), 11 analytes were eliminated with efficiencies of 75 to 100 %, three analytes were eliminated with efficiencies of 50 to 75 % and only one analyte was eliminated with an efficiency of 25 to 50 %.

[0042] Example 4

[0043] The method for eliminating pharmaceuticals from wastewater in example 4 is performed in the same manner as in example 1(a), except that the biological part of the method for eliminating pharmaceuticals from wastewater only allows the encapsulated bacteria to act for 24 hours.

[0044] The photo-oxidation part of the method for eliminating pharmaceuticals from wastewater is performed in the same way as in example 1(b), except that the UV radiation is applied for only 5 minutes.

[0045] The sorption part of the method for eliminating pharmaceuticals from wastewater is performed in the same way as in example 1(c), except that the zinc humate is left to act for 240 minutes.

[0046] The results are given by Table 2. Overall, of the 19 analytes, four were eliminated to below the limit of detection (elimination efficiencies of almost 100 %), 10 analytes were eliminated with efficiencies of 75 to 100 %, four analytes were eliminated with efficiencies of 50 to 75 %, and only one analyte was eliminated with an efficiency of 25 to 50 %.

[0047] Example 5

[0048] The method for eliminating pharmaceuticals from wastewater in example 5 is performed in the same manner as in example 3, except that iron humate is used instead of zinc humate in the sorption part of the method for eliminating pharmaceuticals from wastewater according to paragraph (c).

[0049] In example 5, the method for eliminating pharmaceuticals from wastewater according to the invention achieved a reduction in the concentration of four analytes to below the limit of detection (elimination efficiency of almost 100 %), 10 analytes were eliminated with an efficiency of 75 to 100 %, four analytes were eliminated with an efficiency of 50 to 75 % and only one analyte was eliminated with an efficiency of 25 to 50 %.

[0050] Example 6

[0051] The method for eliminating pharmaceuticals from wastewater in example 6 is performed in the same manner as in example 4, except that iron humate is used instead of zinc humate in the sorption part of the method for eliminating pharmaceuticals from wastewater according to paragraph (c).

[0052] In example 6, the method for eliminating pharmaceuticals from wastewater according to the invention achieved a reduction in the concentration of four analytes to below the limit of detection (elimination efficiency of nearly 100 %), 12 analytes were eliminated with an efficiency of 75 to 100 %, two analytes were eliminated with an efficiency of 50 to 75 % and only one analyte was eliminated with an efficiency of 25 to 50 %.

[0053] Example 7

[0054] The method for eliminating pharmaceuticals from wastewater in example 7 is performed in the same manner as in example 3, except that 300 g of a cartridge containing Pseudomonas fluo- rescens bacteria encapsulated in polyvinyl alcohol lenses is added in the biological part of the method for eliminating pharmaceuticals from wastewater according to the invention.

[0055] In example 7, the method for eliminating pharmaceuticals from wastewater according to the invention achieved a smaller reduction in the concentration of the 19 analytes monitored than in example 3, however, the concentration reduction achieved was still relatively high and in particular in a relatively short time. Overall, of the 19 analytes, one was eliminated to below the limit of detection (elimination efficiency of almost 100 %), nine analytes were eliminated with 75 to 100 % efficiency, six analytes were eliminated with 50 to 75 % efficiency and three analytes with 25 to 50 % efficiency.

[0056] Example 8

[0057] The method for eliminating pharmaceuticals from wastewater in example 8 is performed in the same manner as in example 3, except that 800 g of a filling containing Pseudomonas fluorescens bacteria encapsulated in polyvinyl alcohol lenses is added in the biological part of the method for eliminating pharmaceuticals from wastewater according to the invention.

[0058] In example 8, the method for eliminating pharmaceuticals from wastewater according to the invention achieved a higher degradation efficiency associated with a higher concentration of active microorganisms. Overall, of the 19 analytes, 12 were eliminated to below the limit of detection (elimination efficiencies of almost 100 %), 6 analytes were eliminated with efficiencies of 75 to 100 %, and one analyte was eliminated with efficiencies of 50 to 75 %.

[0059] Industrial applicability

[0060] The method for eliminating pharmaceuticals from wastewater according to the invention is industrially applicable for the treatment of wastewater using a combination of biological, photooxidation and sorption methods for treating the wastewater prior to discharge to receiving water. The method for eliminating pharmaceuticals from wastewater according to the invention is also industrially useful for pretreatment of wastewater with a high concentration of pharmaceuticals or their residues, e.g. hospital wastewater or wastewater from pharmaceutical production.

Claims

CLAIMS A method for eliminating pharmaceuticals from wastewater by biological, photooxidation and sorption methods, characterised in that from 5000 parts by weight of water at 25 °C the pharmaceuticals are first eliminated biologically by adding to it 300 to 800 parts by weight of a filling containing Pseudomonas fluorescens bacteria encapsulated in polyvinyl alcohol lenses and the resulting mixture is maintained in a buoyant state by agitation for 24 to 500 hours, then the biologically pretreated water is homogenised for 3 to 7 minutes, then the pharmaceuticals are eliminated by photooxidation for 5 to 60 minutes by UV irradiation at a relative radiant power of 50 W / L of the purified water with the addition of 0.4 to 0.6 parts by weight of 30% H2O2 and then the pharmaceuticals are eliminated from the biologically and photo -oxidatively pretreated water by sorption by adding 45 to 55 parts by weight of at least one sorbent selected from the group consisting of zinc humate and iron humate and treating with agitation for 30 to 240 minutes.

Images