Effect of the various carbon sources and growth conditions on phosphate release and uptake by Acinetobacter calcoaceticus

The aim of this study was to investigate the influence of various carbon sources applied at different initial concentrations of phosphorus and growth conditions, on the phosphate release and uptake in a pure culture of Acinetobacter calcoaceticus DSM1532. P-release and uptake studies with various carbon sources applied at different initial concentrations of phosphorus were carried out in alternating anaerobic/aerobic batch experiments. The best P-release and P-uptake rates were obtained when sodium propionate was the carbon source. Glucose addition in the synthetic wastewater caused lower P-release and uptake ratios, but did not have any significant influence on the final percentage of P-removal. The highest P-release and P-uptake rates were obtained with the highest phosphorus loadings. The highest P-release resulted in the highest P-uptake rates. The observed aerobic P-uptakes in a batch test, without preliminary resort to anaerobic conditions indicate the probable aerobic mechanism of P-uptake by A. calcoaceticus DSM1532. The results of the semi-continuous test indicate the possibility of the adaptation of A. calcoaceticus DSM1532 to high phosphorus loads (up to 100 mg P L-1) in wastewater

Nutrient removal from leachate of the Zagreb landfill Jakusevec

Remediation of the City of Zagreb Jakuševec Dump Site, one of the largest dump sites in Europe, is in progress. Experimental laboratory results of leachate treatment using aquatic macrophytes show that increasing the concentration of ammonia in the leachate decreases elimination efficiency. In all series of experiments, significantly greater elimination of ammonia and orthophosphates has been obtained in planted than in unplanted mesocosms. For polishing the effluent from the pilot constructed wetland in the polishing pond the following species might be recommended: Phragmites australis, Myriophyllum verticilatum, Ceratophyllum demersum, Lemna minor and Salvinia natans

Plate method for counting proteolytic sulphide-producing bacteria

The proteolytic sulphide-producing bacteria (PSPB) are widely distributed in water and sediment and are a good indicator of the ecological status of ecosystems. From the ecological point of view it is important to distinguish the physiological group of PSPB from other bacteria producing H2S from sulphate, sulphite or thiosulphate. A new medium named peptone-cysteine-ammonium iron citrate agar (PCA) was developed and tested. The medium regularly gave a higher number of colony forming units than the control media for detection of sulphide formation, indole production and motility (Merck) and iron sulphite agar (Oxoid). For the enumeration of PSPB from the environment, the simultaneous incubation of samples in aerobic and anaerobic conditions is recommended and a higher number should be taken for interpretation

Surfaktanti u okolišu

Surfactants are a diverse group of chemicals that are best known for their wide use in detergents and other cleaning products. After use, residual surfactants are discharged into sewage systems or directly into surface waters, and most of them end up dispersed in different environmental compartments such as soil, water or sediment. The toxic effects of surfactants on various aquatic organisms are well known. In general, surfactants are present in the environment at levels below toxicity and in Croatia below the national limit. Most surfactants are readily biodegradable and their amount is greatly reduced with secondary treatment in wastewater treatment plants. The highest concern is the release of untreated wastewater or wastewater that has undergone primary treatment alone. The discharge of wastewater polluted with massive quantities of surfactants could have serious effects on the ecosystem. Future studies of surfactant toxicities and biodegradation are necessary to withdraw highly toxic and non-biodegradable compounds from commercial use and replace them with more environmentally friendly ones.Surfaktanti ili površinski aktivne tvari raznolika su skupina molekula najpoznatijih po uporabi u sastavu deterdženata i ostalih sredstava za pranje i čišćenje. Nakon uporabe u kućanstvu ili industriji, surfaktanti se ispuštaju u kanalizacijski sustav ili izravno u površinske vode te većina surfaktanata završi raspršena u vodi, sedimentu ili tlu. Toksični utjecaj surfaktanata na vodne organizme dobro je istražen i opisan u literaturi. U većini slučajeva surfaktanti su u okolišu prisutni u koncentracijama nižim od toksične te nižim od maksimalne koncentracije dopuštene hrvatskim zakonskim odredbama. Većina surfaktanata klasifi cirana je kao biološki razgradiva i njihova se koncentracija znatno smanjuje biološkom obradom otpadne vode pa je najveći rizik za okoliš ispuštanje prethodno pročišćene ili nepročišćene otpadne vode. Takva otpadna voda opterećena visokim koncentracijama surfaktanata može nepovoljno utjecati na okoliš. Potrebno je proučavati toksičnost i biološku razgradnju surfaktanata u svrhu uklanjanja visoko štetnih i biološki nerazgradljivih surfaktanata iz komercijalne uporabe te njihovu zamjenu tvarima manje štetnim za okoliš

Microbial Colonization of High Density Polyethylene Garbage Bags

This research aimed to determine the microbial colonization and potential biodegradation of classical high density polyethylene (HDPE) garbage bags in conditions which refl ects its real disposal without preliminary abiotic pretreatment. The HDPE fi lms were buried during 14 weeks in containers with humifi ed soil, activated sludge and its mixture. The colonization of heterotrophic mesophilic aerobic and anaerobic bacteria on the HDPE was monitored. The bacteria and fungi formed biofi lms on the surface of HDPE, but did not have the potential to degrade it since no changes in FTIR spectra of HDPE fi lms were observed. The classical HDPE is primary nontoxic inert material, which is not biodegradable in environmental conditions, what represents a serious ecological problem

Use of Natural Zeolite to Upgrade Activated Sludge Process

The objective of this study was to achieve better efficiency of phosphorus removal in an enhanced biological phosphorus removal process by upgrading the system with different amounts of natural zeolite addition. The system performance for synthetic wastewater containing different carbon sources applied at different initial concentrations of phosphorus, as well as for municipal wastewater, was investigated. Natural zeolite addition in the aerobic phase of the anaerobic/aerobic bioaugmented activated sludge system contributed to a significant improvement of phosphorus removal in systems with synthetic wastewater and fresh municipal wastewater. Improvement of phosphorus removal with regard to the control reactors was higher with the addition of 15 than with 5 g/L of natural zeolite. In reactors with natural zeolite addition with regard to the control reactors significantly decreased chemical oxygen demand, ammonium and nitrate, while higher increment and better-activated sludge settling were achieved, without changes in the pH-values of the medium. It was shown that the natural zeolite particles are suitable support material for the phosphate-accumulating bacteria Acinetobacter calcoaceticus (DSM 1532), which were adsorbed on the particle surface, resulting in increased biological activity of the system. The process of phosphorus removal in a system with bioaugmented activated sludge and natural zeolite addition consisted of: metabolic activity of activated sludge, phosphorus uptake by phosphate-accumulating bacteria adsorbed on the natural zeolite particles and suspended in solution, and phosphorus adsorption on the natural zeolite particles

Survival of Acinetobacter baumannii in different water types

Acinetobacter baumannii je oportunistički patogen koji izaziva infekcije imunosuprimiranih bolesnika. S obzirom da je nedovoljno podataka o uspješnosti preživljavanja ovog patogena u prirodnom okolišu, cilj rada bio je odrediti stopu preživljavanja A. baumannii u različitim tipovima voda. Tri izolata A. baumannii višestruko rezistentnih na antibiotike inokulirana su u izvorsku, morsku i izlaznu vodu (efluent) uređaja za pročišćavanje otpadnih voda, te inkubirana na 20°C tijekom 50 dana. U izvorskoj vodi broj vijabilnih A. baumannii bio je konstantan sa stopom preživljavanja 92% nakon 50 dana. U morskoj vodi zabilježen je pad broja bakterija sa stopom preživljavanja 67% nakon 50 dana. U efluentu je došlo do umnažanja bakterija, te je broj A. baumannii bio veći od inicijalnog broja i nakon 50 dana praćenja. Umnažanje te bolje preživljavanje A. baumannii u efluentu u odnosu na izvorsku ili morsku vodu objašnjava se većom dostupnošću nutrijenata. A. baumannii višestruko rezistentni na antibiotike sposobni su preživjeti u različitom vodenom okolišu kroz duže vrijeme, što predstavlja mogućnost njihovog širenja putem voda u prirodni okoliš.Acinetobacter baumannii is an opportunistic bacterial pathogen which causes infections in immunosuppressed patients. Considering insufficient data on the survival success rate of this pathogen in the natural environment, the purpose of this paper was to determine the A. baumannii survival rate in different water types. Three A. baumannii isolates with multiple antibiotic resistance multiply were inoculated in spring water, sea water and wastewater treatment plant effluent and incubated on 20°C in the period of 50 days. The number of viable A. baumannii in spring water was constant, with a survival rate of 92% after 50 days. In sea water, there was a recorded decrease of the bacterial numbers with a survival rate of 67% after 50 days. The bacteria in the effluent multiplied, and the number of A. baumannii was higher than the initial number even after 50 days of monitoring. The multiplication of bacteria and improved survival of A. baumannii in the effluent in comparison to spring or sea water is attributed to higher nutrient availability. A. baumannii with multiple antibiotic resistance can survive in different aquatic environments for a longer time period, which provides an opportunity for its spreading through water into the natural environment

Verhalten vom Burkholderia cepacia-Komplex in Gewässern bei unterschiedlichen Nährstoffkonzentrationen

Skupina od 20-ak vrsta bakterija zvanih Burkholderia cepacia kompleks (BCC) rasprostranjene su u okolišu, ali su i uzročnici teških infekcija kod ljudi. Na području Republike Hrvatske provedeno je relativno malo istraživanja o prisutnosti ovih bakterija u različitim staništima i utjecaju ovih bakterija na ljude. U ovom radu ispitano je dugoročno ponašanje pet klinički značajnih BCC-ova u vodama različite koncentracije hranjiva. Klinički izolat i četiri izolata izdvojena iz okoliša utjecanim ljudskim tekućim ili krutim otpadom dugoročno su preživjela i čak se umnažala u vodi siromašnoj ili bogatoj hranjivima. Nakon 50 dana praćenja, koncentracija četiri od pet ispitanih izolata u vodi bila je viša od početne koncentracije. S obzirom na potencijal dugoročnog zadržavanja klinički značajnih BCC-ova u vodenim ekosustavima, prisutnost BCC-ova u vodi treba smatrati izvorom sporadičnih infekcija ljudi. Kako bi se izbjegao ovaj javnozdravstveni rizik, potrebno je ukloniti BCC-ove iz ljudskog krutog i tekućeg otpada prije odlaganja u okoliš. U svrhu praćenja epidemiologije BCC-ova potrebno je posvetiti pažnju izolaciji i karakterizaciji BCC-ova u klinici i okolišu.A group of about 20 bacteria species called the Burkholderia cepacia complex (BCC) are widespread in the environment, but they are also the cause of severe infections in humans. In the Republic of Croatia, relatively little research has been conducted on the presence of these bacteria in different habitats and the impact these bacteria have on humans. The paper examines the long-term behaviour of five clinically significant BCC bacteria species in waters with different nutrient concentrations. The clinical isolate and four isolates extracted from the environment impacted by human liquid or solid waste survived in the long term and even multiplied in nutrient-poor or nutrient-rich water. After a 50-day monitoring, the concentration of four out of the five tested isolates in water was higher than the initial concentration. Considering the potential for a long-term retention of clinically significant BCC bacteria species in aquatic ecosystems, the presence of the BCC in water should be considered as a source of sporadic human infections. In order to avoid this public health risk, the BCC should be removed from human solid and liquid waste before its disposal in the environment. For monitoring of the BCC epidemiology, it is necessary to payEtwa zwanzig Spezies vom Burkholderia cepacia-Komplex (BCC) kommen in der Umgebung vor und sind Erreger von schweren Infektionen bei Menschen. Auf dem Gebiet Kroatiens sind relativ wenige Untersuchungen zur Anwesenheit dieser Bakterien in verschiedenen Lebensräumen oder zu den Auswirkungen dieser Bakterien auf Menschen durchgeführt worden. In diesem Artikel wird langfristiges Verhalten von fünf klinisch relevanten Bakterien Burkholderia cepacia in Gewässern mit unterschiedlichen Nährstoffkonzentrationen untersucht. Das klinische Isolat und vier andere, aus der von menschlichen flüssigen oder festen Abfällen beeinflussten Umwelt isolierten Isolate, überlebten und sogar vermehrten sich im nährstoffreichen aber auch im nährstoffarmen Wasser. Nach 50 Tagen Überwachung war die Konzentration der vier Isolate (von insgesamt fünf untersuchten Isolaten) im Wasser höher als die Anfangskonzentration. Unter Berücksichtigung des Potenzials einer langfristigen Retention vom klinisch relevanten Burkholderia cepacia-Komplex in aquatischen Ökosystemen soll die Anwesenheit des Burkholderia cepacia-Komplexes im Wasser als Infektionsquelle bei Menschen angesehen werden. Um diese Gefahr für die öffentliche Gesundheit zu vermeiden, soll der Burkholderia cepacia-Komplex aus dem menschlichen festen und flüssigen Abfall vor der Entsorgung entfernt werden. Zum Zwecke der Überwachung der Epidemiologie des Burkholderia cepacia-Komplexes ist es notwendig, auf Isolierung und Charakterisierung des Burkholderia cepacia-Komplexes sowohl in Klinik als auch in Umwelt zu achten