<p>U radu su predstavljeni rezultati&nbsp; ispitivanja biolo&scaron;ke&nbsp;<br />stabilnosti vode za piće primenom rotirajućih prstenastih reaktora (eng.&nbsp;<br />rotating annular reactor, RAR). Pomoću RAR praćen je uticaj odabranih&nbsp;<br />faktora na suspendovani i pričvr&scaron;ćeni mikrobni rast pri kontrolisanim&nbsp;<br />laboratorijskim uslovima koji su simulirali distributivne sisteme. Pored&nbsp;<br />toga, u cilju potpunog razumevanja biolo&scaron;ke stabilnosti vode za piće&nbsp;<br />izvr&scaron;eno je ispitivanje metoda za određivanje biodegradabilne frakcije<br />organske materije, BDOC i AOC test.</p><p>Poređenjem BDOC testova sa nativnom populacijom bakterija&nbsp;<br />pričvr&scaron;ćenom za pesak iantracit utvrđena je efikasnija primena biolo&scaron;kog&nbsp;<br />aktivnog peska. Primenom peska za inokulaciju uzorka, vrednost BDOC&nbsp;<br />u podzemnoj vodi sa teritorije srednjeg Banata iznosila je 1,27 mgC/l. U<br />ispitivanju AOC testa sa suspendovanim standardnim kulturama&nbsp;<br />Pseudomonas fluorescens P17 (ATCC 49642) i Spirillum sp. NOX&nbsp;<br />(ATCC 49643), AOC iskori&scaron;ćen od strane NOX je imao veću vrednost u&nbsp;<br />odnosu na P17, &scaron;to pokazuje da su karboksilne kiseline dominantan&nbsp;<br />supstrat za rast. Vrednost AOC u tretiranoj podzemnoj vodi iznosila 32&nbsp;<br />&mu;g acetat-C/l. Veće vrednosti BDOC ukazuju na prisustvo jedinjenja&nbsp;<br />veće molekulske mase u ovoj frakciji u odnosu na AOC frakciju&nbsp;<br />biodegradabilne organske materije.</p><p>U ispitivanju biostabilnosti podzemne vode sa teritorije srednjeg&nbsp;<br />Banatatokom tretmana, najveća količina biofilma je razvijena u RAR sa&nbsp;<br />ozoniranom vodom (13,30 CFU/cm²), &scaron;to potvrđuje efekte ozonizacije na&nbsp;<br />biodegradabilnost organske materije i ponovni rast mikroorganizama.&nbsp;<br />Tokom tretmana zabeleženo je variranje razvoja biofilma, pri čemu je&nbsp;<br />najmanji stepen rasta biofilma uočen u RAR sa vodom nakon GAC&nbsp;<br />filtracije (1,10 CFU/cm²).</p><p>Tokom mikrobne kolonizacije test-pločica RAR pri laminarnom i&nbsp;<br />turbulentnom protoku uočen je sličan trend rasta bakterija u biofilmu u sintetičkoj sme&scaron;i organskih i neorganskih nutrijenata. Međutim, tokom dominacije suspendovanog rasta u sistemu voda-biofilm pri neprotocnim uslovima, pona&scaron;anje biofilmova razvijenih pri protočnim (laminarnim i turbulentnim) uslovima je bilo različto. Uočen je manji udeo bakterija prisutnih u vodenoj fazi kod biofilma nastalim pri turbulentnom protoku u odnosu na veće oslobađanje ćelija iz biofilma nastalim pri laminarnim uslovima, nakon 48h 78% i 89% suspendovanih bakterija, redom. Ovi rezultati pokazuju da su biofilmovi razvijeni pri turbulentnom protoku snažniji, stabilniji &nbsp; i jače pričvr&scaron;ćeni nego pri laminarnom protoku.</p><p>Tokom praćenja sekundarne kolonizacije odvojenih ćelija biofilma&nbsp;<br />uočeno je da se primarni biofilm pona&scaron;a kao stalni rezervoar ćelija koje&nbsp;<br />su sposobne da zauzmu nove povr&scaron;ine vrlo brzo pri različitim&nbsp;<br />hidrodinamičkim uslovima. Brojnost bakterija u biofilmu razvijenom na&nbsp;<br />sekundarnim test-pločicama nakon 24 h iznosila je 32000&plusmn;1200&nbsp;CFU/cm^2&nbsp;<br />u odnosu na 16&plusmn;1 CFU/cm^2&nbsp;primarne test-pločice. Ustanovljen&nbsp;<br />je izraženiji potencijal kolonizacije novih povr&scaron;ina odvojenim želijama iz&nbsp;<br />primarnog biofilma koji je formiran pri turbulentnim uslovima u odnosu&nbsp;<br />na laminarne uslove.</p><p>Proces stvaranja biofilma na test-pločicama od nerđajućeg čelika&nbsp;<br />(SS), polivinilhlorida(PVC) i polietilena(PE) je bio vrlo sličan. Samo&nbsp;<br />debljina biofilma je bila veća na PE (4,0-5,5 kg/m³) nego na SS i PVC&nbsp;<br />test-pločicama (2,7-3,6 kg/m^3&nbsp;i 2,8-3,9 kg/m³, redom). Ustanovljen je&nbsp;<br />uticaj materijala cevi na rast biofilma u RAR snabdevanim vodom iz&nbsp;<br />distributivnog sistema grada Novog Sada, naročito za vreme početne faze&nbsp;<br />procesa. Biofilmovi formirani na različitim materijalima u RAR su uticali&nbsp;<br />na mikrobiolo&scaron;ki kvalitet vode, zavisno od njihove bakterijske gustine.&nbsp;</p><p>SEM analiza potvrdila je prisustvo biofilma na test-pločicama u&nbsp;<br />eksperimentima, ukazujući na uspe!nu primenu RAR u ispitivanju&nbsp;<br />biofilma i biostabilnosti vode za piće.</p><p>Rezultati dobijeni tokom ispitivanja ukazuju da se primenom&nbsp;<br />odabranih i optimizovanih, zavisno od cilja ispitivanja i vrste uzorka,&nbsp;<br />BDOC i AOC testova može efikasno definisati biolo!ka stabilnost vode&nbsp;<br />za piće. Pored toga, sistematski pristup odabiru odgovarajućih materijala&nbsp;<br />cevi, koji je zasnovan na pouzdanim testovima i definisanim&nbsp;<br />kriterijumima, može se primeniti u cilju osiguravanja kvaliteta vode sa&nbsp;<br />mikrobiolo&scaron;kog aspekta.</p><p>Ispitivanja su pokazala uspe&scaron;nu primenuRAR u simulaciji&nbsp;<br />mikrobnog rasta u cevima pri kontrolisanim laboratorijskim uslovima i&nbsp;<br />značaj istovremenog ispitivanja imobilisanog i suspendovanog rasta u&nbsp;<br />definisanom hidrodinamičkom sistemu.&nbsp; Primena RAR kao model biofilma je ukazala na njegov značaj u ispitivanju potencijala ponovnog naseljavanja povr&scaron;ina otkinutih delova i/ili pojedinačnih ćelija biofilma za uspostavljanje efikasne kontrole mikrobnih problema u distributivnim sitemima vode za piće.</p> / <p>This thesis presents theresults of investigation of drinking water biostability using the&nbsp; rotating annular reactor (RAR). The effects of selected factors on the suspended and attached microbial growth under controlled laboratory conditions that simulated the&nbsp;distribution systems were monitored using RAR. In addition, in order to completeunderstanding of the drinking water biological stability,&nbsp;methods for determining biodegradable organic matter fractions, BDOC&nbsp;and AOC methods were tested.</p><p>Comparing the BDOC tests with the native population of bacteria&nbsp;attached to sand and anthracite, a better application of biologically active&nbsp;sand was established. Using BDOC test with sand, the BDOC value in&nbsp;groundwater from the territory of the Central Banat (Republic of Serbia)&nbsp;was 1.27 mgC/L. In the investigation of AOC tests with standard&nbsp;<br />suspended culture of Pseudomonas fluorescens P17(ATCC 49642) and&nbsp;Sprillumsp. NOX (ATCC 49643), AOC utilized by NOX had a higher&nbsp;value compared to the P17, which shows that the carboxylic acid are&nbsp;dominant substrate for growth. The AOC value in the treated ground&nbsp;water was 32 &mu;g acetate-C/L. The higher BDOC values indicate the&nbsp;presence of higher molecular weight compounds in this fraction&nbsp;compared to the AOC biodegradable fraction of organic matter.&nbsp;</p><p>In the investigation of biostability during treatment of&nbsp;groundwater from the territory of the Central Banat (Republic of Serbia),&nbsp;the largest amount of biofilm was developed in the RAR with ozonated&nbsp;water (13.30 CFU/cm²), confirming the effects of ozonation on organic&nbsp;matter biodegradability and microbial regrowth. During treatment the&nbsp;<br />variation of biofilm development was detected and in the RAR with water after GAC filtration the lowest level of biofilm growth (1.10 CFU/cm²) was observed.&nbsp;</p><p><span style="font-size: 12px;">During the microbial colonization of the RAR test-coupons under&nbsp;</span><span style="font-size: 12px;">laminar and turbulent flow, the similar trend of growth of bacteria in the&nbsp;</span><span style="font-size: 12px;">biofilm in synthetic mixture of organic &nbsp;and inorganic nutrients was&nbsp;</span><span style="font-size: 12px;">observed. However, the higher numbers of immobilized bacteria under&nbsp;</span><span style="font-size: 12px;">the turbulent conditions in the same growth period (16 days) were&nbsp;</span><span style="font-size: 12px;">recorded. During the domination of suspended growth in water-biofilm system under &nbsp;non-flow conditions, the behavior of biofilms developed under flow (laminar and turbulent) conditions were different. There was a smaller proportion of bacteria present inthe aqueous phase of the biofilm formed under the turbulent flow over a larger release of cells &nbsp;from biofilms formed under laminar conditions, after 48h 78% and 89% of the suspended &nbsp;bacteria, respectively. These results indicate that biofilms developed under turbulent flow &nbsp;were stronger, more stable and more strongly attached than the ones under laminar flow.</span></p><p>During monitoring of the secondary colonization of the dettached&nbsp;biofilm cells, it was noted that the primary biofilm was a constant&nbsp;reservoir of cells that are able to occupy the new areas very quickly&nbsp;under different hydrodynamic conditions. The abundance of bacteria in&nbsp;the biofilm developed on the secondary test-coupons after 24 h was 32&nbsp;<br />000&plusmn;1200 CFU/cm² compared to 16&plusmn;1 CFU/cm²on the primary test-coupons. A stronger potential for colonization of new areas by dettached&nbsp;cells from the primary biofilm formed under the turbulent conditions in&nbsp;comparison to laminar conditions was found.&nbsp;</p><p>The biofilm formation processes on SS, PVC and PE test-coupons&nbsp;werevery similar. Only biofilm thickness was greater on the PE (4.0 to&nbsp;5.5 kg/m³) than the SS and PVC &nbsp;test-coupons (2.7 to 3.6 kg/m³ and 2.8 to&nbsp;3.9 kg/m³, respectively). There was a slight influence of pipe material on&nbsp;the biofilm growth, especially during the initial stages of the process.&nbsp;Biofilms formed on different materials in the RAR with water from the&nbsp;distribution system of the city of Novi Sad (Vojvodina, Republic of&nbsp;Serbia) have showed the influence on the microbiological quality of&nbsp;water, depending on their bacterial density.</p><p>SEM analysis confirmed the biofilm presence on test-coupons in&nbsp;the experiments, indicating the successful implementation of RAR in the&nbsp;examination of biofilm and drinking water biostability.&nbsp;</p><p><span style="font-size: 12px;">The results obtained during the investigations indicate that the&nbsp;</span><span style="font-size: 12px;">application of selected and optimized, depending on the test objective&nbsp;</span><span style="font-size: 12px;">and sample types, BDOC and AOC tests can effectively define the&nbsp; biological stability. In addition, a systematic approach for &nbsp;electing appropriate pipe materials, which is based on reliable tests and defined criteria, specific for the investigated drinking water distribution system can be applied to ensure &nbsp;he water quality from a microbiological point of view.</span></p><p>The investigations have shown the successful application of RAR&nbsp;in the simulation of microbial growth in the pipes under controlled&nbsp;laboratory conditions as well as the importance of simultaneous&nbsp;examination of immobilized and suspended growth under defined&nbsp;hydrodynamic system. Implementation of RAR as amodel biofilm&nbsp;indicated its importance in examining the potential resettlement area by&nbsp;dettached parts and/or individual biofilm cells to establish effective&nbsp;control of microbial problems in the drinking water distribution system.&nbsp;</p>