UNIVERSITY OF NOVA GORICA GRADUATE SCHOOL THE STUDY OF OPTIMAL TECHNOLOGICAL PROCEDURES OF INTERNAL PLUMBING SYSTEM DISINFECTION FACILITIES IN USE BY THE SENSITIVE HUMAN POPULATIONS MASTER´S THESIS Janez Škarja Mentor: Assis. Prof. Darko Drev Nova Gorica, 2016 UNIVERZA V NOVI GORICI FAKULTETA ZA PODIPLOMSKI ŠTUDIJ RAZISKAVA OPTIMALNIH TEHNOLOŠKIH POSTOPKOV DEZINFEKCIJE INTERNIH VODOVODNIH OMREŽIJ OBJEKTOV, KI JIH UPORABLJA OBČUTLJIVEJŠA POPULACIJA LJUDI MAGISTRSKO DELO Janez Škarja Mentor: doc.dr. Darko Drev Nova Gorica, 2016 SUMMARY In a developed world, water is used in a variety of installations and devices for the improvement of life standard. It is important for these elements to be suitably managed and maintained, otherwise they can present a risk to people's health. Although potable water from a public plumbing system coming via the water supply into an internal plumbing system normally is compliant with the regulations, the quality of water in an internal plumbing system often changes – water gets contaminated. There are several types of microorganisms that can grow in water. While most of them present no threat, there are some that can induce health issues in people. Internal plumbing systems with heated water and the possibility of aerosol releasing present a special concern in this matter. They carry a great potential for the growth and proliferation of bacteria from the genus Legionella that cause Legionnaires' disease and Pontiac Fever. Even the fact that Legionella infection has for several years been mentioned in the accident insurance conditions of insurance companies in relation to receiving the insurance fee as compensation for bed day, shows the extent and foremost the seriousness of the disease (5–15% mortality rate). The research part of the master thesis focused mainly on determining the presence of bacteria from the genus Legionella in the water of internal plumbing systems of healthcare facilities. During the entire research period of 8 years, 2,676 samples of cold and hot water were acquired from 23 healthcare facilities. The main purpose of the research was to determine the efficiency or adequacy of applied approaches, i.e. physical disinfection with heat and chemical disinfection with chlorine, in eliminating or reducing the amount of Legionella present in the water of selected healthcare facilities. Another aim was to evaluate the impact of softening potable water with polyphosphates on the proliferation of certain microorganisms in water, and to determine the by-products of chemical disinfection. Upon sampling, an organoleptic examination of water (appearance, odour), electrometric measurements of water temperature, and colorimetric measurements of free chlorine concentrations in water were performed. The data for the analysis of V Legionella presence were acquired by water sampling and the isolation of bacteria found in the water. In order to acquire laboratory results of specific physical and chemical parameters, ion chromatography, gas chromatography, spectrophotometry, titration, and inductively coupled plasma – mass detector were used. Although water samples from only two healthcare facilities showed no presence of Legionella, the number of water samples with the presence of Legionella decreased for at least 25% from the beginning to the end of period set. Also, after certain general sanitary and technical measures a noticeable improvement within healthcare facilities after 2008 could be observed. Regarding the initial part of the set period, a more favourable relationship between positive and negative samples, a lower number of samples with highest concentrations of present Legionella, and a higher number of samples with lower concentrations of present Legionella were determined. The highest shares of positive samples were observed in the classes with concentrations from 11 to 100 and 101 to 1,000 CFU/mL. Furthermore, the share of most often determined species Legionella pneumophila sg.1 decreased as well. The research has shown that the existing system of ensuring health-compliant water is fairly efficient; however, the results could be improved additionally by investing more into the preparation and renovation of systems. Due to a limited number of samples, a direct impact of adding polyphosphates to potable water could not be linked to the occurrence of Legionella. None of the samples showed an increased concentration of by-products of potable water disinfection. In its conclusion, the research has shown that the procedures after overheating and after chlorine disinfection result in a similar success. While filtration proved to be most efficient, from the perspective of Legionella infections the use of medical bathtubs can present a high risk to people's health, therefore such devices should be subject to more frequent maintenance and supervision. Not only did medical bathtubs produce a high share of positive samples, the majority of samples with highest concentrations of Legionella were also found in them. The comparison of results could indeed show the actual effects more thoroughly, had there been a chance to monitor the execution of individual preventive measures at the VI same collection spots. Therefore, a certain degree of attention needs to be taken into account when interpreting the results. Keywords: potable water, internal plumbing system, biofilm, health facilities, disinfection, Legionella VII POVZETEK V razvitem svetu se voda uporablja v raznolikem spektru napeljav in naprav za izboljšanje življenjskega standarda. Pomembno je, da se te elemente ustrezno upravlja in vzdržuje, saj v nasprotnem primeru lahko predstavljajo tudi tveganja za zdravje ljudi. Kljub dejstvu, da je pitna voda iz javnega vodovodnega omrežja, ki prihaja preko vodovodnega priključka v interno vodovodno omrežje običajno skladna s predpisi, se v slednjem kakovost pogosto spremeni – voda se onesnaži. Obstajajo številni mikroorganizmi, ki lahko rastejo v vodi. Medtem ko je večina neškodljivih, nekateri povzročajo obolenja pri ljudeh. Interni vodovodni sistemi z ogrevano vodo in možnostjo sproščanja aerosolov so v tem pogledu še posebej zaskrbljujoči. Omenjeni sistemi imajo velik potencial za rast in širjenje bakterij iz rodu Legionella, ki povzročajo legionarsko bolezen in pontiaško vročico. Tudi to, da najdemo okužbo z Legionella že nekaj let omenjeno tudi v pogojih zavarovalnic za nezgodno zavarovanje, v povezavi z izplačilom zavarovalnine kot nadomestila za bolnišnični dan, kaže na razširjenost, predvsem pa na težo obolenja (5-15% smrtnost). V raziskovalnem delu smo se osredotočili predvsem na ugotavljanje prisotnosti bakterij iz rodu Legionella v vodi iz internih vodovodnih omrežij zdravstvenih objektov. V celotni raziskavi je bilo v osem letnem obdobju, v 23 zdravstvenih objektih skupaj odvzeto 2676 vzorcev hladne in tople vode. Glavni namen je bil raziskati učinkovitost oziroma zadovoljivost uporabljenih pristopov, kot so fizikalna dezinfekcija s toploto in kemična dezinfekcija s klorom, za odstranjevanje oziroma zmanjšanje števila Legionella v vodi izbranih zdravstvenih objektov. Namen je bil tudi oceniti vpliv mehčanja pitne vode s polifosfati na razrast nekaterih mikroorganizmov v vodi in določitev stranskih produktov kemične dezinfekcije. Ob vzorčenju pitne vode iz pip, prh, iztokov hranilnikov, filtrov na mestih uporabe je bil opravljen organoleptični pregled vode (izgled, vonj), elektrometrične meritve temperature vode, kolorimetrične meritve koncentracije prostega klora v vodi. VIII Podatke za analizo prisotnosti Legionella smo pridobili z vzorčenjem vode in osamitvijo bakterij iz vode. Za pridobitev laboratorijskih rezultatov določenih fizikalno kemijskih parametrov smo uporabili ionsko kromatografijo, plinsko kromatografijo, spektrofotometrijo, titracijo, induktivno sklopljeno plazmo – masni detektor. Kljub temu, da v vodi le v dveh zdravstvenih objektov nismo ugotovili Legionella, pa se je od začetka do konca obravnavanega obdobja vsaj za 25% zmanjšalo število vzorcev vode s prisotnostjo Legionella. V letu 2006 je delež pozitivnih vzorcev tako znašal 71,7 %, leta 2013 pa 44,0 %. Tudi z nekaterimi splošnimi sanitarno tehničnimi ukrepi se je po letu 2008 vidno začelo izboljševati stanje v zdravstvenih objektih. Ugotovili smo ugodnejše razmerje med pozitivnimi in negativnimi vzorci, manjše število vzorcev z najvišjimi koncentracijami prisotnih Legionella in večje število vzorcev z nižjimi koncentracijami prisotnih Legionella, glede na začetni del obravnavanega obdobja. Največji delež pozitivnih vzorcev sta predstavljala velikostna razreda s koncentracijami od 11 do 100 in od 101 do 1,000 CFU/mL. Zmanjšal se je tudi delež, sicer najpogosteje ugotovljene vrste Legionella pneumophila sg.1. Raziskava je pokazala, da je obstoječi sistem zagotavljanja zdravstveno ustrezne vode dokaj učinkovit, a menimo, da je možno z večjim vlaganjem v pripravo in obnovo sistemov rezultate, glede prisotnosti Legionella v vodi internih vodovodnih sistemov, še izboljšati. Zaradi omejenega števila vzorcev (N=12), kjer smo izmeril tudi koncentracijo ortofosfatov, nismo mogli povezati neposredni vpliv dodajanja polifosfatov v pitno vodo na razvoj Legionella. Raziskovali smo tudi prisotnost klorida, klorita, klorata, THM – vsota (Kloroform, Bromoform, Bromodiklorometan, Dibromoklorometan) v pitni vodi. V nobenem vzorcu nismo ugotovili povečane koncentracije stranskih produktov dezinfekcije pitne vode. V zaključku raziskava izkazuje, da sta bila postopka po pregrevanju in dezinfekcija s klorom podobno uspešna glede ugotovljenega