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Here we study the photocatalytic degradation of the antibiotic ciprofloxacin (CIP) supported by sol-gel Ce-doped TiO2 photocatalyst nanoparticles. The photocatalyst samples consist of Ce in 0.08, 0.40, 0.80, 2.40 and 4.10 wt.%. For the preparing of the sols we used titanium isopropoxide and cerium (III) nitrate hexahydrate as precursors, 2-propanol as a solvent, acetylacetone as a complexation agent, distilled water as a hydrolysis agent, and nitric acid as a hydrolysis/polycondensation catalyst. The Ce-TiO2 sol was deposited on borosilicate glass samples using a flow coating method. After deposition, films were dried at 100 °C for 1 hour and heat-treated at 450 °C for 2 hours at a heating rate of 3 °C/min. The activity and efficiency of Ce- TiO2 films for photocatalytic degradation of the CIP under simulated solar radiation was investigated, especially the influence of the changing irradiation intensity. The weight loss as well as exothermic and endothermic reactions during the thermal treatment, were obtained by simultaneous differential thermal and thermogravimetric analysis (DSC/TGA). The phase composition and parameters and volumes of the unit cells were determined by X-ray diffraction (XRD). Atomic force microscopy (AFM) was used to describe surface morphology and roughness parameters of the films. Photocatalytic studies indicate that TiO2 photocatalyst with 0.80 wt. % Ce showed the highest rate of degradation of ciprofloxacin using simulated solar radiation.

Trimethoprim (2, 4-diamino-5(3’, 4’, 5’-trimetoxybenzylpyrimidine) (TMP) is an antifolate antibacterial agent used worldwide in veterinary and human medicines for the treatment of bladder infections. It is often prescribed in combination with sulfamethoxazole due to their complementary and synergistic mechanisms but may be used as a monotherapy [1]. Due to its frequent use and very low elimination rate in WWTPs, TMP has been often detected in wastewater effluents and surface waters. Previous study has shown that TMP is resistant to biodegradation and hydrolysis, while solar radiation can cause slow degradation of TMP in favourable environmental conditions and lead to a decrease in its environmental concentration [1]. In this work, the mechanism of TiO2 photocatalytic and photolytic (without photocatalyst) degradation of TMP was investigated. TiO2 photocatalyst was used in a form of nanostructured film on glass ring placed on the bottom of the reactor [2]. As a source of radiation a simulated solar radiation lamp was used both for photolytic and photocatalytic experiments. The photocatalytic mechanism has been elucidated by scavenger studies using isopropanol, ammonium oxalate and triethanolamine as hydroxyl radicals, positive holes and superoxide radicals scavengers, respectively [3]. The results showed strong inhibition of photocatalytic degradation of TMP in presence of isopropanol and triethanolamine, which means that •OH and superoxide radicals were the primary reactive radicals responsible for the degradation process. No inhibition of the photocatalytic degradation of TMP in presence of ammonium oxalate was observed.

U ovom radu praćene su koncentracije kalcija i magnezija, kao i prisutnost Legionella spp. u 121 uzorku tople vode, koji su uzorkovani u šest objekata (četiri hotela i dva doma za starije i nemoćne osobe) na području Splitsko–dalmatinske županije. U sklopu istraživanja provedena je Anketa o tehničko–tehnološkim karakteristikama objekata te su pritom prikupljeni podatci koji su važni za kvalitetu tople vode. U radu su se koristile osnovne statističke metode kao i neparametrijski test za određivanje povezanosti između kemijskih pokazatelja i prisutnosti Legionella spp. Utvrđena je statistički značajna pozitivna korelacija većih koncentracija iona Ca i Mg otopljenih u vodi s prisutnošću Legionella spp. Provedenim istraživanjem utvrđen je veći broj uzoraka koji su bili pozitivni na Legionella spp., a koji su uzorkovani iz toplovodnih sustava s centralnim zagrijavanjem vode (17 %), u odnosu na pozitivne uzorke na Legionella spp., a koji su uzorkovani iz decentralnih sustava zagrijavanja vode (9 %). Stoga je opravdano pretpostaviti da na prisutnost Legionella spp. utječe, osim sastava vode, i tehničko-tehnološka izvedba sustava za pripremu potrošne tople vode., The paper presents the monitoring of calcium and magnesium concentrations, as well as the presence of Legionella spp. in 121 warm water samples collectedfrom six facilities (4 hotels and 2 nursing homes) in the Split-Dalmatia County. The research included a survey on technical and technological characteristics of the facilities, providingdata important for the quality of warm water. The research included standard statistical methods and a nonparametric test for determining the connection between the chemical indicators and the presence of Legionella spp. A statistically significant positive correlation of higher concentrations of Ca and Mg ions dissolved in water with the presence of Legionella spp. was determined. It was further determined that a larger number of samples collected from warm water systems with central water heating (17%)were positive for Legionella spp. in comparison to samples collected from decentralised water heating systems (9%). For this reason, it is justified to assume that, in addition to water composition, the technical and technological execution of preparation systems for consumable warm water affects the presence of Legionella spp. as well., In diesem Beitrag wurden die Calcium- und Magnesiumkonzentrationen sowie die Anwesenheit von Bakterien Legionella spp. in 121 Warmwasserproben beobachtet, die in sechs Einrichtungen (vier Hotels und zwei Altersheimen) auf dem Gebiet der Gespanschaft Split-Dalmatien entnommen wurden. Im Rahmen der Untersuchung wurde auch eine Umfrage über technisch-technologische Eigenschaften der Einrichtungen einschließlich der für die Warmwasserqualität wichtigen Angaben durchgeführt. Im Beitrag wurden die grundlegenden statistischen Methoden sowie der nichtparametrische Test zur Bestimmung des Verhältnisses zwischen chemischen Parametern und der Anwesenheit von Legionella spp. verwendet. Es konnte statistisch signifikante Korrelation zwischen höheren Konzentrationen von im Wasser gelösten Calcium- und Magnesiumionen und der Anwesenheit von Legionella spp. bestimmt werden. In der durchgeführten Untersuchung wurde eine größere Zahl von Proben bestimmt, die positiv auf Legionella spp. waren und welche aus Warmwassersystemen mit zentraler Warmwasserbereitung (17%) entnommen wurden, im Vergleich zu den positiven Proben, die aus dezentralen Warmwasserbereitungssystemen (9%) entnommen wurden. Folglich kann man annehmen, dass auf die Anwesenheit von Legionella spp. außer Wasserzusammensetzung auch die technisch-technologische Leistungsfähigkeit eines Warmwasserbereitungssystems Einfluss hat.

Photocatalytic oxidation process, with heterogeneous photocatalysts, as one of the Advanced Oxidation Processes (AOPs), can be effective technology in the oxidation/degradation of different water pollutants. The main problem with manipulation with photocatalyst (usually TiO2 particles in the size range 20-30 nm) is the need to separate them after the photocatalytical oxidation process and reuse them for further process of degradation of pollutants. In this study two different methods (growth of magnetite crystals on the photocatalyst surface and formation of photocatalytic nano-film on the magnetite core) for preparation of magnetic photocatalysts was applied and magnetic technology was used for separation of particles from water. Photocatalysts were successfully prepared and reused with the efficiency of more than 90% and also successfully used for different water pollutants –pharmaceutics and natural organic matter.

Pitka voda, osim što je vrlo dobro otapalo, pogodan je medij za mikrobiološki rast i razvoj. Zato je česta pojava u vodnim instalacijama da se sastav vode promijeni od izvorišta, i kemijski i mikrobiološki, do takve razine da predstavlja opasnost za ljudsko zdravlje. Direktiva Europske unije 2020/2184 od 16. 12. 2020. (stupila na snagu u siječnju 2021.) nameće nova pravila, kako u promjenama dopuštenih koncentracija određenih parametara u vodi do uvođenja potpuno novih odnosa u ispitivanju voda – uvedena je i posebna grupa zahtjeva na tzv. interne ili kućne vodoopskrbne mreže koje imaju specifične probleme i opasnosti za čije rješavanje će biti potrebna velika pažnja i suradnja interdisciplinarnih timova stručnjaka. Sve zemlje članice morat će prilagoditi vlastito zakonodavstvo tako da bude u potpunosti usklađeno sa zahtjevima ove Direktive najkasnije do siječnja 2023. godine. Velika pažnja bit će posvećena slučajevima nekontroliranog povećanja koncentracije patogenih mikroorganizama u vodi (npr. Legionella pneumophila) čime se može ugroziti život korisnika takve vode. U tom procesu bit će potrebno proučiti najbolje svjetske prakse kako bi se došlo do jasnih smjernica za prvi korak u rješavanju problema – a to je izrada idejnih studija za različite potrebe sustava, korištenje ispravnih projektantskih rješenja za rekonstrukcije postojećih sustava te novih zgrada što bi sve imalo za konačni cilj – smanjenje opasnosti za ljude koji koriste takve sustave. Takvo projektiranje bi se moglo prozvati higijenskim projektiranjem i u sklopu ove prezentacije prikazat će se osnovna načela kojih bi se projektanti trebali pridržavati da bi se postigao traženi cilj – ispravna pitka voda na svakoj slavini u građevini.

Primjena termalnih i mineralnih voda u toplicama i wellness centrima, u bazenima ili u kupkama, predstavlja liječnicima dragocjenu pomoć u prevenciji, rehabilitaciji i promicanju zdravlja ljudi. Pri tome je od izuzetne važnosti osigurati zdravstvenu ispravnost takvih voda, između ostaloga i zbog činjenice da su korisnici često i imunokompromitirane osobe. Unatoč višestoljetnoj (ili čak višetisućljetnoj) tradiciji primjene vode u lječilišne (balneološke) svrhe, nigdje u svijetu nije propisan jasan sastav niti maksimalne dopuštene koncentracije nekih ključnih parametara u takvim vodama. U području ljekovitih voda danas se primjećuje cijeli niz nedorečenosti – od jasnoće odnosa sastava vode i zdravstvenog efekta, osnovne terminologije vezane uz grupe takvih voda do načina postizanja i održavanja kvalitete vode koja neće ugroziti zdravlje ljudi koji je koriste. Jedan od glavnih problema je postizanje i održavanje mikrobiološke ispravnosti lječilišne vode jer uobičajeni dezinfekcijski postupci bitno mijenjaju izvornost sastava ovih voda i, pretpostavlja se, umanjuju njihov lječilišni efekt te ih, barem što se tiče zakonodavca, pretvaraju iz lječilišnih u bazenske vode. U radu je dan i pregled uvjeta primjene inovativnih rješenja i tehnologija obrade vode (prvenstveno dezinfekcijskih postupaka) koje bi mogle biti prikladne za očuvanje izvornosti ovakvih tipova voda u što većem stupnju.

U ovom su članku opisane i sažete strategije i mjere koje bi se trebale primjenjivati u Hrvatskoj u svrhu sprječavanja kontaminacije bakterijom Legionella vodoopskrbnih sustava različitih ustanova tijekom pandemije COVID-a19. Kolonizacija bakterije Legionella u vodovodnim instalacijama povećava rizik od zaraze ljudi, stoga je važno istaknuti da je ovaj problem javnog zdravstva još veći tijekom drugih epidemija. Legionella može uzrokovati vrlo ozbiljne vrste upale pluća, tzv. legionarsku bolest i manje opasnu pontijačku groznicu. Hrvatska će u svoje zakonodavstvo transponirati preinaku EU Direktive 2020/2184 o kvaliteti vode za ljudsku potrošnju koja po prvi puta uključuje obvezu procjene rizika od bakterije Legionella. To bi trebalo pomoći u smanjenju zdravstvenih rizika ili komplikacija respiratornih infekcija (teške upale pluća) i smrtnosti tijekom drugih epidemija (COVID-a19 ili sl.)., This paper describes and summarizes the strategies and measures that should be applied in Croatia to prevent Legionella contamination in drinking water systems in buildings during the COVID-19 epidemic. Legionella colonisation in drinking water installations increases the risk of infection for humans and it is important to point out that this public health problem is even greater during other epidemics. Legionella can cause very severe types of pneumonia called Legionnaires’ disease and less serious illness Pontiac fever. Therefore, Croatia will implement the new EU Directive 2020/2184 on the quality of water intended for human consumption into its legislation, which for the first time includes an obligation to assess the risk of Legionella. This should help reduce the health risk or complications of respiratory infections (severe pneumonia) and mortality during other epidemics (COVID-19 and similar)., In diesem Beitrag werden die Strategien und Maßnahmen beschrieben und zusammengefasst, die in Kroatien angewendet werden sollen zum Zwecke der Vorbeugung der Kontamination von Wasserversorgungssystemen verschiedener Institutionen mit Legionella-Bakterien während der COVID-19-Pandemie. Die Ansiedlung von Legionella-Bakterien in Wasserinstallationen erhöht das Infektionsrisiko beim Menschen, deswegen ist es wichtig darauf hinzuweisen, dass dieses Problem des öffentlichen Gesundheitswesens noch größer während anderer Epidemien ist. Legionellen können sehr schwere Arten von Lungenentzündungen verursachen, die sgn. Legionärskrankheit und das weniger gefährliche Pontiac-Fieber. Kroatien wird durch seine Gesetze die Richtlinie (EU) 2020/2184 über die Qualität von Wasser für den menschlichen Gebrauch umsetzen, die zum ersten Mal die Anforderung der Risikobewertung eines Versorgungssystems in Bezug auf Legionellen enthält. Das sollte helfen, die Gesundheitsrisiken oder Komplikationen von Atemweginfektionen (schwere Lungenentzündungen) sowie die Sterblichkeit während anderer Epidemien (COVID-19 und ähnliche) zu reduzieren.

When using thermal and mineral waters, it is necessary to pay attention to the safety of their use for medicinal purposes (in spas), in terms of achieving and maintaining water parameters at intervals that will guarantee users all the benefits of using such water, while the possibility of deteriorating health would be reduced to a minimum. Due to the specific and diverse composition of such waters, the relationship between their composition and their impact on human health has not been fully clarified. It is necessary to develop a new strategy and introduce analyses and monitoring of new parameters of thermal and mineral waters in order to achieve a better interpretation of their effects on the body, but also to monitor the condition of users of health services. One of the main problems is to achieve and maintain the microbiological safety of water because the usual disinfection procedures significantly change the originality of the composition of these waters and, presumably, reduce their healing effect. The paper also provides an overview of the conditions for the application of innovative solutions and technologies for water treatment (primarily disinfection processes) that could be suitable for preserving the originality of these types of water to the greatest extent possible.

TiO2 heterogeneous photocatalysis is actively studied as an alternative technology for the degradation and/or removal of organic micropollutants (OMPs) present in water [1-2]. However, photoactivation of TiO2 occurs only under UV light and the photogenerated charges that start oxidation processes recombine quite fast, affecting the photocatalytic activity [3]. Therefore, this study focuses on the synthesis of nitrogen-doped TiO2 for enhancing its photocatalytic activity under visible light, using the non-conventional microwave- assisted method, and evaluating the amount of nitrogen on the photocatalytic activity under different sources of radiation for the degradation of a model pollutant – antibiotic drug ciprofloxacin in aqueous solution. Nitrogen-doped TiO2 (N/TiO2) photocatalyst was synthesized by the microwave-assisted method, using urea as a nitrogen source. To evaluate the effect of nitrogen in the photocatalytic and morphological properties, N/TiO2 were prepared varying the amount of urea. The obtained materials were characterized by XRD, FTIR, Raman spectroscopy and N2 adsorption isotherms. The only crystalline phase present in the N/TiO2 materials was anatase. The incorporation of urea as a nitrogen source does not affect the crystallinity either the crystal phase of TiO2. Although the urea incorporation reduces the specific surface area, the obtained materials have three times bigger surface area than commercial catalyst Degussa P25. N/TiO2 materials show photoactivity under UV, Solar light simulator and visible light, while commercial photocatalyst Degussa P25 TiO2 shows activity only under UV light and Solar light simulator. Increasing the amount of urea increases the photocatalytic activity of the materials under the different radiation sources for the degradation of ciprofloxacin. However, beyond a specific concentration, there is no further improvement of the materials' photoactivity.

In the last 20 years, organic micropollutants (OMPs) have gained significant attention because of their possible impact on the environment. Besides, they cannot be easily removed by conventional wastewater treatment technologies. TiO2 heterogeneous photocatalysis is actively studied as an alternative technology for the degradation and/or removal of OMPs. Therefore, this study focuses on the synthesis of enhanced photocatalyst, which could use visible light for activation, using the non-conventional microwave-assisted method, and evaluating the role of the temperature and reaction time on the morphological properties of the synthesized materials. Nitrogen-doped TiO2 (N/TiO2) photocatalyst was synthesized by the microwave-assisted method using varying temperatures and reaction times. The obtained materials were characterized by XRD, FTIR and N2 adsorption isotherms. The only crystalline phase present in the N/TiO2 materials was anatase. Higher crystallinity and greater crystallite size were achieved for synthesis at higher temperature. N/TiO2 materials’ photocatalytic activity was evaluated for the degradation of ciprofloxacin under UV and visible light. They show photoactivity under both UV and visible light, while commercial photocatalyst Degussa P25 TiO2 shows activity only under UV light. Better photoactivity was achieved with materials synthesized at a higher temperature, whereas reaction time in the microwave oven has a negligible effect on the morphologic and photocatalytic properties. Temperature was found to be the crucial parameter in the synthesis of N/TiO2 by the microwave-assisted method.

Od davnina čovjek koristi termalne i mineralne vode u ljekovite svrhe, uglavnom u objektima pod nazivom – toplice. Ta tendencija korištenja toplica u zadnje se vrijeme još i povećava. Prilikom korištenja termalnih i mineralnih voda potrebno je obratiti pažnju na sigurnost korištenja vode, u smislu postizanja i održavanja parametara vode u onim intervalima koji će jamčiti korisnicima sve beneficije korištenja takve vode, a da pri tome mogućnost pogoršanja zdravlja bude svedena na minimum. Zbog specifičnog sastava takvih voda jedan je od glavnih problema postizanje i održavanje mikrobiološke ispravnosti vode jer uobičajeni dezinfekcijski postupci na bazi kloriranja vode u većini slučajeva kod ovakvih voda nisu prikladni. U radu se najprije diskutira o prikladnosti naziva ljekovita, termalna, mineralna, termomineralna i geotermalna voda, zatim slijedi pregled primjenjivih propisa, a nakon toga dan je pregled uvjeta primjene tehnologija obrade vode (prvenstveno dezinfekcijskih postupaka) koje su prikladne za ovakve tipove voda kao i osvrt na moguća rješenja i nove tehnologije za koje se očekuje da će biti u primjeni u skoroj budućnosti.

This document presents conclusions and recommendations based on the technical findings of the project PROSEU to assist prosumers to choose their suitable renewable prosumer technology depending on their need, demands, size and location. Further, it offers recommendations that can support the implementation and mainstreaming of prosumer technologies. Besides this, it also gives an overview of the key prosumer technologies and their technical, economical, ecological and social parameters as well as giving some best practice examples. &nbsp

The aim of this research is to evaluate environmental impacts of utilizing biogas and digestate produced by anaerobic digestion (AD) of residue grass. Three different grass types (grass from the uncultivated land area − RG1, riverbank grass − RG2 and verge next to the highway – RG3) from uncultivated lands have been considered. Experimental research on grass digestate quality has shown the share of macronutrients is impacted by the position where grass grows. In that means the following share of macronutrients has been determined: nitrogen − between 0.148 and 0.161 kg(N)/kgTS, phosphorus − between 0.0161 and 0.0184 kg(P)/kgTS, and potassium − between 0.391 and 0.655 kg(K)/kgTS. Using data on biogas yield and digestate quality as an input for Life Cycle Assessment, the following four scenarios have been studied: i) Production of heat and electricity using biogas without digestate utilisation (a base scenario) ; ii) Production of heat and electricity using biogas followed by utilisation of a digestate as a fertiliser ; iii) Upgrading of biogas to biomethane without digestate utilisation, and iv) Upgrading of biogas to biomethane followed by utilisation of a digestate as a fertiliser. Results of the research have shown that RG2 grass type gains the greatest benefits in terms of health category within the single score, but also the highest increase in Global warming potential (GWP) compared to other grasses. Upgrading of biogas to biomethane contributes significantly to single score benefits, but also to slightly higher GWP compared to electricity and heat production using biogas. On the other hand, application of grass digestate as a fertiliser positively contributes to environmental performance, increasing the overall single score by ca. 2-fold and decreasing the GWP potential by ca. 10 %.

U instalacijama pitke vode u objektima mogu se razviti fizikalne, kemijske i mikrobiološke opasnosti. Zato je potrebno već u fazi projektiranja poznavati te opasnosti i u postupku projektiranja provoditi postupke kojima će ih se učinkovito izbjeći. Spomenute opasnosti mogu se razvrstati u tri osnovne grupe: A - rast i razvoj patogenih mikroorganizama (npr. Legionella pneumophila, Pseudomonas aeruginosa) ; B - nepovoljni fizikalno-kemijski parametri (temperatura, tlak, otopljene ili suspendirane tvari čiji sastav djeluje nepovoljno na ljude, buka) i C - opasnosti pri uporabi vode (tijekom konzumacije vode, apsorpcijom kroz kožu, udisanje vodenog aerosola). Iako se određenim tehničkim rješenjima smanjuju mogućnosti kontaminacije unutar razvoda instalacija pitke vode, mnoga istraživanja vodoopskrbnih sustava pokazuju značajna odstupanja od osnovnih higijenskih pravila. Općenito, čimbenici koji pridonose problemu higijene sustava su sljedeći: neprimjerena veličina cijevi ili spremnika vode, upotreba neprikladnih materijala i/ili komponenata sustava, nepravilno korišteni dijelovi cjevovoda sa stagnacijom vode, uvjeti pogodni za stvaranje biofilma, nepridržavanje temperaturnih ograničenja, neispravna ili nestručno postavljena instalacija, neprimjerena tlačna proba, nepropisna montaža i nepropisno puštanje sustava u rad. U ovom radu kroz stručne smjernice, norme i preporuke iznose se problemi, ali i mogućnosti postizanja higijenskih uvjeta u projektiranju instalacija pitke vode. Predlažu se i naknadne mjere u već postojećim sustavima u kojima su uočene nepravilnosti

U radu je opisan sol-gel postupak priprave TiO2 fotokatalizatora dopiranog s cerijem te njegova imobilizacija i korištenje u fotokatalitičkoj razgradnji farmaceutika. Za pripravu solova korišteni su: titanijev izopropoksid i cerijev (III) nitrat heksahidrat kao prekursor, 2-propanol kao otapalo, acetilaceton za kompleksiranje, destilirana voda za hidrolizu te nitratna kiselina kao katalizator. Cerij je dodan u sljedećim udjelima: 0, 08%, 0, 40%, 0, 80%, 2, 40%, 4, 10% te 73, 3%. Sol Ce-TiO2 nanesena je na borosilikatna stakalca metodom izlijevanja, nakon čega slijedi sušenje pri 100 °C, 1 h te toplinska obrada na 450 °C, 2 h. Na dobivenim filmovima provedeno je ispitivanje njihove fotokatalitičke djelotvornosti razgradnje antibiotika ciprofloksacina (CIP) tijekom 120 min pod UV-A zračenjem i zračenjem sličnom Sunčevom. CIP je antibiotik širokog spektra koji u posljednje vrijeme predstavlja opasnost okolišu zbog prevelikih koncentracija u vodama. Mikroskopijom atomskih sila (AFM) određena je morfologija površine filmova i parametri hrapavosti. Simultanom toplinskom analizom DSC/TG dobiveni su podaci o gubitku mase pri zagrijavanju uzoraka, ali i podaci o egzotermnim i endotermnim reakcijama. Rendgenskom difrakcijom (XRD) određen je fazni sastav te parametri i volumeni jediničnih ćelija uzoraka. Fotokatalitičkim i fotolitičkim ispitivanjima utvrđeno je da dopiranjem TiO2 s Ce dolazi do ukupnog povećanja djelotvornosti razgradnje ciprofloksacina kada se umjesto čistog UV-A zračenja primjeni zračenje slično Sunčevom. Eksperimentalni rezultati pokazuju da pri ozračenju reaktora i UV-A zračenjem i zračenjem sličnom Sunčevom, TiO2 fotokatalizator dopiran s 0, 08% Ce ima najveću brzinu razgradnje ciprofloksacina.

Pitka voda koju ljudi neposredno koriste u zgradama obično se razlikuje od pitke vode koja se isporučuje s postrojenja za pripremu pitke vode i koja se šalje u vodovodni sustav. Osnovni razlog za to je činjenica da je voda tzv. univerzalno otapalo i uvijek, u većoj ili manjoj mjeri, otapa tvari s kojima je u neposrednom kontaktu pa se neprekidno povećava koncentracija tvari u vodi pristiglih iz materijala razvodnog sustava. Drugi razlog je u činjenici da je voda pogodan medij za mikrobiološki rast i razvoj. U pojedinim slučajevima moguće je da se nekontrolirano poveća koncentracija patogenih mikroorganizama u vodi (npr. Legionella pneumophila) čime voda postaje opasna po život. U instalacijama pitke vode mogu se razviti fizikalne (previsoka temperatura i/ili tlak), kemijske (otapanje materijala razvodnog sustava, dezinfekcijski nusprodukti) i mikrobiološke (bakterije, virusi) opasnosti kojih često korisnici nisu uopće svjesni. Metodologija sprječavanja ovih opasnosti i upravljanje njima mora se temeljiti na suradnji stručnjaka različitih profila. U toj suradnji mora se pristupiti izradi procjene rizika nastanka opasnosti u instalacijama pitke vode u zgradi, izradi preporuka za tehnološko-strojarske mjere kojima bi se otklonila ili smanjila opasnosti te izradi procedura za održavanje i upravljanje sustavom pitke vode. Osim lokalnih mjera na objektima, od velike pomoći bilo bi poticanje uključivanja svih navedenih struka u kontinuirani pritisak prema mjerodavnim službama kako bi usvojili jasnije i detaljnije pravne akte koji se tiču kvalitete pitke vode u zgradama.

Advanced oxidation processes (AOPs) have proven to be among the most effective techniques for the removal of micropollutants from water samples. Depending on the properties of the waste stream to be treated, AOPs can be employed either alone or coupled with other physicochemical and biological processes or as a tertiary treatment. One of the vital factors in photocatalytic processes is the source of light. Since widely used mercury lamps have several drawbacks, other sources of light are receiving more interest in last years. Light emitting diodes (LEDs) have several advantages over traditional UV lamps such as a better efficiency, lower power requirements and longer lifetimes. In addition, they are less harmful to the environment because they are free of toxicants (e.g. mercury). The aim of this study was to evaluate photocatalytic degradation of metoclopramide (MCP), a pharmaceutic widely used for stomach and esophageal problems. The experimental study included evaluation of MCP adsorption on the photocatalytic film (stirring „in the dark“), photolytic and photocatalytic degradation experiments. Near ultraviolet light emitting diode (NUV-LED) lamps with a peak wavelength of 405 nm and 365 nm (wavelengths that can be found in natural solar spectrum) were used as alternative light sources. TiO2 in a form of a film deposited on borosilicate glass ring placed on the bottom of the reactor was used. Process degradation efficiencies and evaluation of kinetic constants were based on HPLC-MS/MS analyses, which also enable identification and monitoring of MCP degradation products. Photodegradation of MCP followed pseudo-first- order kinetics, and the kinetic constant of photocatalysis at 365 nm was much higher (0.0247 min-1) than constant obtained at 405 nm (0.0046 min-1). Adsorption of MCP on photocatalytic film and its photolytic degradation were not observed. The chemical structures of two detected photodegradation products were suggested based on mass spectra.

Textile industry effluents pose environmental risks due to the persistence of the additives and dye residues but membrane technology can effectively remove these contaminants. Since membranes, especially ceramic membranes are prone to fouling, which results in reduced membrane performance and increased operational costs, pretreatment may be necessary. Wastewater containing reactive dye (Novacron Orange) was treated with a 1 kDa tubular multichannel ceramic membrane. Several versions of pretreatment solutions were experimented with, including filtration with submerged polyethylene (PE) hollow fiber membrane combined with different concentrations of magnesium chloride as coagulant to test the optimal efficiency. The rate of pollutant removal was characterized with the decrease in total organic carbon (TOC) concentration and color intensity reduction. Modelling removal performance may assist the technology to predict fouling and necessary cleaning frequency. A membrane separation model was developed earlier by the research group to simulate filtration efficiency by combining a fouling model including pore blockage, pore constriction and cake layer formation with a modified Spiegler‐Kedem‐Katchalsky model for ultrafiltration to assess the permeate concentration as a function of the change in permeate flow rate. Experimental data from the treatment of the reactive dye wastewater were fed to the model to test its validity under different conditions. Parameters that are sensitive to the different types of pretreatment (membrane filtration and coagulation) were identified and comparative analysis of the results was carried out to evaluate the robustness of the model and to provide a clear understanding of membrane separation mechanisms regarding reactive dye removal from textile wastewater.

Da bismo lakše sagledali problem postupanja u slučaju zagađenja nekog sustava distribucije pitke vode legionelama, najprije je potrebno proučiti propise i druge obvezujuće akte koje za tu temu treba osigurati svaka država. Nažalost, svijest o problemu zagađenja sustava legionelama nije u svim državama na istoj razini pa tako i zakonodavstvo u različitim državama pokazuje odstupanja u pokazanoj ozbiljnosti povezanoj s tim problemom. Najozbiljniji problem koji se može pojaviti u sustavima distribucije pitke vode zagađene legionelama jest izbijanje epidemije legionarske bolesti koja u znatnom postotku može završiti smrtnim posljedicama. Ključnu ulogu u prevenciji takvih problema imaju propisi i kontrola njihova provođenja. U sklopu propisa trebale bi postojati i jasne upute ne samo za postupanje u slučaju detekcije zagađenja legionelama, nego i za ranije faze – projektiranje objekata i sustava distribucije vode te njihovu izgradnju. Zbog pogrešaka u planiranju, izvedbi, radu ili održavanju, kvaliteta pitke vode može se pogoršati u instalacijama tako da zahtjevi postavljeni za pitku vodu (definirani pravilnicima) ne mogu biti ispunjeni – tipični primjeri su zagađenja mikroorganizmima: npr. Legionella pneumophila, Pseudomonas aeuriginosa i dr. Prema navodima Verein Deutscher Ingeniuere (VDI) na analiziranim sustavima (364 slučaja) u kojima su pronađene pogreške koje su dovodile do zagađenja sustava opskrbe vodom, čak 69, 2% slučaja pogrešnog postupanja odnosilo se na faze projektiranja (36, 5%) i izvođenja (32, 7%) sustava [1]. U nastavku će biti prikazani propisi koji su na snazi u SAD-u, EU i Republici Hrvatskoj, a tiču se pitke vode i legionela. Osim toga, bit će prikazani načini dezinfekcije (fizikalni i kemijski) te njihove prednosti i nedostatci.

Today, synthetic organic dyes are used in various industries. Wastewaters containing these dyes may be harmful to the environment, animals, and people. It is very important to degrade these dyes before discharging them into the environment. Heterogeneous photocatalysis could be effective in the degradation of organic dyes. A major advantage is the mineralization of organic dyes, which result in CO2, H2O, and corresponding mineral acids. TiO2 as a photocatalyst has of great interest due to its high activity, photochemical inertness, non- toxicity, efficiency, and low cost. The biggest drawbacks of TiO2 photocatalysis are the high bandgap energy (3.2 eV) and the easy recombination of photoinduced electron-hole pairs. That limits its feasibility for the photocatalytic application in a visible light region. The aim of this study was to synthesize the TiO2-rGO (titania-reduced graphene oxide) nanoparticles as photocatalysts in the visible light region. The graphene oxide was synthesized from natural graphite powder by Hummer's method. TiO2 sol was prepared by using titanium tetraisopropoxide as a precursor, i-propanol as a solvent, acetylacetone as a chelating agent and nitric acid as a catalyst. The TiO2-rGO nanoparticles with different amounts of GO were prepared on a borosilicate glass substrate by using the sol- gel dip-coating method. They were characterized by means of powder X-ray diffraction analysis, Fourier transform infrared spectroscopy and Scanning electron microscopy. The photocatalytic activities of the TiO2-rGO nanoparticles were evaluated by the degradation of the aqueous solution of methylene blue (MB) dye as a model pollutant. The irradiation was simulated with a light- emitting diode (LED) lamp with a radiation peak at 365 nm and a Solar-simulator lamp. The concentrations of MB were monitored by UV-Vis spectrophotometry. Obtained results indicated that photocatalytic properties of prepared TiO2-rGO nanoparticles depend on the amount of rGO and on the type of the irradiation source.

Kontinuirano održavanje kvalitete pitke i potrošne tople vode u objektima u kojima borave ljudi, posebno naglašavajući mikrobiološke zahtjeve za kvalitetom vode, predstavlja veliki izazov za stručnjake iz različitih područja djelovanja. Patogene bakterije iz roda Legionella nalaze se u prirodnim vodotokovima i dospijevaju sustavom vodoopskrbe do objekata. Predstavljaju opasnost za ljudsko zdravlje izazivajući legionarsku bolest koja može završiti smrtnim ishodom. Svijest o problemu zagađenja vodnih sustava legionelama nije u svim državama na istoj razini pa tako i zakonodavstvo u različitim državama pokazuje odstupanja u pokazanoj ozbiljnosti povezanoj s tim problemom. U radu su prikazani zakonski zahtjevi vezani uz kvalitetu pitke vode u odabranim državama te navedeni primjeri ograničenja vezani uz prisutnost bakterija roda Legionella. Zbog pogrešaka u planiranju, izvedbi, radu ili održavanju, kvaliteta pitke vode može se pogoršati u instalacijama tako da zahtjevi postavljeni za pitku vodu (definirani pravilnicima) ne mogu biti ispunjeni – tipični primjeri su zagađenja patogenim mikroorganizmima: npr. Legionella pneumophila, Pseudomonas aeuriginosa i dr. U radu su prikazani i pojašnjeni postupci kemijske i fizikalne dezinfekcije, kontinuirane i povremene, tzv. „šok“ dezinfekcije te su obrazložene njihove prednosti i nedostatci.