Microbiological contamination of a hemodialysis center water distribution system

The microbiological monitoring of the water used for hemodialysis is extremely important, especially because of the debilitated immune system of patients suffering from chronic renal insufficiency. To investigate the occurrence and species diversity of bacteria in waters, water samples were collected monthly from a hemodialysis center in upstate São Paulo and tap water samples at the terminal sites of the distribution system was sampled repeatedly (22 times) at each of five points in the distribution system; a further 36 samples were taken from cannulae in 19 hemodialysis machines that were ready for the next patient, four samples from the reuse system and 13 from the water storage system. To identify bacteria, samples were filtered through 0.22 µm-pore membranes; for mycobacteria, 0.45 µm pores were used. Conventional microbiological and molecular methods were used in the analysis. Bacteria were isolated from the distribution system (128 isolates), kidney machine water (43) and reuse system (3). Among these isolates, 32 were Gram-positive rods, 120 Gram-negative rods, 20 Gram-positive cocci and 11 mycobacteria. We propose the continual monitoring of the water supplies in hemodialysis centers and the adoption of effective prophylactic measures that minimize the exposure of these immunodeficient patients to contaminated sources of water.

Modelling and optimization of the ion exchange membrane bioreactor for removal of anionic pollutants from drinking water streams

Dissertação para obtenção do Grau de Doutor em Engenharia Química, especialidade de Engenharia Bioquímica

Removal of Erythrosine B dye from water effluents using crop waste pumpkin seed hulls as adsorbent

Erythrosine B is widely used for coloring in various applications, especially in the food industry, despite its already proved toxicity and carcinogenicity. The agrowaste pumpkin seed hulls were applied as potential adsorbent for the removal of Erythrosine from aqueous solutions. Adsorption mechanism and kinetics were analyzed for design purposes. The seed hulls were characterized by specific techniques before and after dye retention. It was found that the attachment of Erythrosine B molecules on adsorbent surface may be attributed to the interactions between carboxyl and/or carbonyl groups of both dye and agrowaste wall components. A univariate approach followed by a factorial design was applied to study and analyze the experimental results as well as to estimate the combined effects of the process factors on the removal efficiency and dye uptake. Adsorption mechanism may be predominantly due to intraparticle diffusion, dependent on pore size. The four equilibrium models applied fitted the data well; the maximum adsorption capacity for Erythrosine was 16.4 mg/g. The results showed that adsorbent is effective for Erythrosine B removal for a large concentration range in aqueous solutions (5400 mg/L) in batch systems.

Removal of tetracycline from contaminated water by Moringa oleifera seed preparations

The aim of this study was to evaluate tetracycline antibiotic (TA) removal from contaminated water by Moringa oleifera seed preparations. The composition of synthetic water approximate river natural contaminated water and TA simulated its presence as an emerging pollutant. Interactions between TA and protein preparations (extract; fraction and lectin) were also evaluated. TA was determined by solid phase extraction followed by high performance liquid chromatography - mass spectrometry. Moringa extract and flour removed TA from water. Extract removed TA in all concentrations and better removal (40%) was obtained with 40 mg L1; seed flour (particles < 5mm), 1.25 g L1 and 2.50 g L1 removed 28 and 29% of tetracycline, respectively; particles > 5 mm (0.50 g L1) removed 55% of antibiotic. Interactions between TA and seed preparations were assayed by haemagglutinating activity (HA). Specific HA (SHA) of extract (pH 7) was abolished with tetracycline (5 mg L1); fraction (75%) and lectin HA (97%) were inhibited with TA. Extract SHA decreased by 75% at pH 8. Zeta potential (ZP) of extract 700 mg L1 and tetracycline 50 mg L1 , pH range 5 to 8, showed different results. Extract ZP was more negative (10.73 mV to 16.00 mV) than tetracycline ZP (0.27 mV to 20.15 mV); ZP difference was greater in pH 8. The focus of this study was achieved since moringa preparations removed TA from water and compounds interacting with tetracycline involved at least lectin binding sites. This is a natural process, which do not promote environmental damage.

Planta pilot d'una potabilitzadora

Treball de recerca realitzat per alumnes d'ensenyament secundari i guardonat amb un Premi CIRIT per fomentar l'esperit científic del Jovent l'any 2009. El treball ha consistit en dissenyar i construir una planta pilot d'una potabilitzadora que simulés el funcionament de les plantes potabilitzadores, basada en els mateixos principis . La Planta pilot de la potabilitzadora consta de les següents operacions: desbast, floculació, decantació, filtració de sorra, aireació, filtració de carbó actiu i desinfecció. La mostra utilitzada per la potabilització s’ha obtingut de l’embassament del Pasteral, lloc on la planta potabilitzadora de Girona capta l’aigua. Una vegada potabilitzada s’han realitzat una sèrie d’anàlisis tant a l’entrada com a la sortida, per determinar la variació obtinguda en diferents paràmetres del procés. Els tipus d’anàlisis realitzats són: fisicoquímics, microbiològics i organolèptics. Finalment, s’ha realitzat una comparació amb la potabilitzadora de Girona i s’ha verificat mitjançant els paràmetres de la normativa de l’aigua l'estat de la mostra.

Expression of a plant-derived peptide harboring water-cleaning and antimicrobial activities.

Drinking water is currently a scarce world resource, the preparation of which requires complex treatments that include clarification of suspended particles and disinfection. Seed extracts of Moringa oleifera Lam., a tropical tree, have been proposed as an environment-friendly alternative, due to their traditional use for the clarification of drinking water. However, the precise nature of the active components of the extract and whether they may be produced in recombinant form are unknown. Here we show that recombinant or synthetic forms of a cationic seed polypeptide mediate efficient sedimentation of suspended mineral particles and bacteria. Unexpectedly, the polypeptide was also found to possesses a bactericidal activity capable of disinfecting heavily contaminated water. Furthermore, the polypeptide has been shown to efficiently kill several pathogenic bacteria, including antibiotic-resistant isolates of Staphylococcus, Streptococcus, and Legionella species. Thus, this polypeptide displays the unprecedented feature of combining water purification and disinfectant properties. Identification of an active principle derived from the seed extracts points to a range of potential for drinking water treatment or skin and mucosal disinfection in clinical settings.

Functionality of the plastron in adults of Neochetina eichhorniae Warner (Coleoptera, Curculionidae): aspects of the integument coating and submersion laboratory experiments

The plastron theory was tested in adults of Neochetina eichhorniae Warner, 1970, through the analysis of the structure that coats these insects' integument and also through submersion laboratorial experiments. The tegument processes were recognized in three types: agglutinated scales with large perforations, plumose scales of varied sizes and shapes, and hairs. The experiments were carried out on 264 adult individuals which were kept submerged at different time intervals (n = 11) and in two types of treatment, natural non-aerated water and previously boiled water, with four repetitions for each treatment. The tests showed a maximum mortality after 24 hours of immersion in the previously boiled water treatment. The survival of the adults was negative and significantly correlated with the types of treatment employed and within the different time intervals. The values of oxygen dissolved in water (mg/l) differed significantly within the types of treatment employed. They were positively correlated with the survival of the adults in the two types of treatment, although more markedly in the treatment with previously boiled water. The mortality of adults after 24 hours of submersion in the treatment with previously boiled water may be associated with the physical-chemical conditions of the non-tested water in this study, such as low surface tension and concentration of solutes. These results suggest plastron functionality in the adults of this species.

Proyecto de ejecución de zona lúdica de verano formada por piscinas, jacuzzi y edificio de servicios

Este trabajo final de carrera se basa en la redacción de un proyecto de ejecución de una zona lúdica situada en el interior del recinto de un camping, la cual estará formada por una piscina de grandes dimensiones formada por tres vasos de tipo desbordante, una piscina de tipo infantil, un jacuzzi y finalmente un edificio de servicios complementarios (bar, aseos y enfermería). La piscina grande estará formada por tres vasos donde el agua va deslizándose de uno a otro hasta ser recogida por un depósito de compensación desde donde se realizará la filtración y tratamiento antes de ser devuelta al piscina de nuevo. La instalación está también preparada para ser utilizado cada vaso como una piscina individual, recogiendo el agua por los rebosaderos laterales y conduciéndola al mismo vaso de compensación. El tratamiento del agua se realizará de forma física a través de la filtración mediante filtros de arena y de forma química analizando la cantidad de cloro residual y el nivel de PH y posteriormente añadiendo de forma automática las cantidades de cloro y corrector de PH adecuados mediante bombas dosificadoras de precisión. La piscina infantil es de pequeñas dimensiones y esta preparada para ser utilizada por niños de muy corta edad. Se diferencia de la piscina grande en el sistema de recirculación de agua (en este casos e utilizarán skimmers) y en el tratamiento posterior, ya que se utilizará el sistema de hidrólisis salina para su desinfección en lugar de añadir directamente cloro. Este sistema de tratamiento del agua no es tan agresivo como el tradicional, siendo cada vez mas utilizado en piscinas de mediano y pequeño tamaño. El jacuzzi es de grandes dimensiones, disponiendo de su propio sistema de tratamiento de agua, utilizando el sistema de hidrólisis salina como en el caso de la piscina infantil. El edificio de servicios dispone de zonas de bar, enfermería y aseos. Se ha descrito desde la estructura a las instalaciones, justificando las conclusiones a través de los cálculos correspondientes, bien de forma manual, bien utilizando diverso software especializado.

Reuse of Lime Sludge from Water Softening and Coal Combustion Byproducts, TR-459, 2004

Disposal of lime sludge remains a major challenge to cities in the Midwest. Disposal of lime sludge from water softening adds about 7-10% to the cost of water treatment. Having effective and safe options is essential for future compliance with the regulations of the State of Iowa and within budget restrictions. Dewatering and drying are essential to all reuse applications as this affects transportation costs and utility. Feasibility tests were conducted on some promising applications like SOx control in power generation facilities that burn coal, replacement of limestone as an ingredient in portland cement production, dust control on gravel roads, neutralization of industrial wastewater pH, and combination with fly ash or cement in construction fill applications. A detailed report and analysis of the construction fills application is presented in the second half of the report. A brief discussion of the results directly follows.

Applications for Reuse of Lime Sludge from Water Softening, TR-535, 2005

Lime sludge, an inert material mostly composed of calcium carbonate, is the result of softening hard water for distribution as drinking water. A large city such as Des Moines, Iowa, produces about 30,700 tons of lime sludge (dry weight basis) annually (Jones et al., 2005). Eight Iowa cities representing, according to the United States (U.S.) Census Bureau, 23% of the state’s population of 3 million, were surveyed. They estimated that they collectively produce 64,470 tons of lime sludge (dry weight basis) per year, and they currently have 371,800 tons (dry weight basis) stockpiled. Recently, the Iowa Department of Natural Resources directed those cities using lime softening in drinking water treatment to stop digging new lagoons to dispose of lime sludge. Five Iowa cities with stockpiles of lime sludge funded this research. The research goal was to find useful and economical alternatives for the use of lime sludge. Feasibility studies tested the efficacy of using lime sludge in cement production, power plant SOx treatment, dust control on gravel roads, wastewater neutralization, and in-fill materials for road construction. Applications using lime sludge in cement production, power plant SOx treatment, and wastewater neutralization, and as a fill material for road construction showed positive results, but the dust control application did not. Since the fill material application showed the most promise in accomplishing the project’s goal within the time limits of this research project, it was chosen for further investigation. Lime sludge is classified as inorganic silt with low plasticity. Since it only has an unconfined compressive strength of approximately 110 kPa, mixtures with fly ash and cement were developed to obtain higher strengths. When fly ash was added at a rate of 50% of the dry weight of the lime sludge, the unconfined strength increased to 1600 kPa. Further, friction angles and California Bearing Ratios were higher than those published for soils of the same classification. However, the mixtures do not perform well in durability tests. The mixtures tested did not survive 12 cycles of freezing and thawing and wetting and drying without excessive mass and volume loss. Thus, these mixtures must be placed at depths below the freezing line in the soil profile. The results demonstrated that chemically stabilized lime sludge is able to contribute bulk volume to embankments in road construction projects.

Sellu ja paperiteollisuuden jätevesien tertiäärikäsittelyn kemikaloinnin optimointi

Kuluneen vuosikymmenen aikana metsäteollisuuden päästöt ympäristöön ovat pienentyneet huomattavasti tuotantomäärien kasvustahuolimatta. Lainsäädännön myötä lupa-arvot tiukentuvat edelleen joten olemassa olevia puhdistus prosesseja on parannettava ja niiden rinnalle on kehitettävä uusia, yhä tehokkaampia menetelmiä. Aquaflow Oy suunnittelee jäteveden puhdistamoja sellu- ja paperiteollisuuteen. Kilpailun kiristyessä kilpailuetua haetaan jatkuvan kehittymisen kautta. Yhä useammilla jäteveden puhdistamoilla tarvitaan teriäärikäsittely biohajoamattoman aineksen poistamiseen. Tertiäärikäsittely on käyttökustannuksiltaan kallis kemikaali kulutuksensa vuoksi. Tässä työssä pyrittiin optimoimaan tertiääriprosessin kemikaalien syöttöä. Lisäksi selvitettiin millaisissa oloissa keskeiset saostus ja flokkaus prosessit toimivatparhaiten, sekä mitkä tekijät vaikuttavat merkittävästi jäteveden kemiallisen käsittelyn tulokseen. Saatujen tulosten perusteella kemikaalien sekoituksen tehostuksen seurauksena kemikaali määriä voidaan pienentää, samalla puhdistustulos paranee ja jäännöskemikaalien määrä pienenee. pH:n säätö on olennainen osa prosessin toiminnan kannalta, jos pH ei ole kemikaalien toiminta alueella ei puhdistusta tapahdu ja kemikaalit kulkeutuvat luontoon. Tertiäärikäsittelyyn tulevan jäteveden online seurannan avulla juuri oikea kemikaaliannos olisihelpompaa määrittää kuin päivän viiveellä tulevien laboratorio analyysien perusteella ja yli-/ali annostukselta vältyttäisiin

Wet Oxidation of Concentrated Wastewaters: Process Combination and Reaction Kinetic Modeling

The accumulation of aqueous pollutants is becoming a global problem. The search for suitable methods and/or combinations of water treatment processes is a task that can slow down and stop the process of water pollution. In this work, the method of wet oxidation was considered as an appropriate technique for the elimination of the impurities present in paper mill process waters. It has been shown that, when combined with traditional wastewater treatment processes, wet oxidation offers many advantages. The combination of coagulation and wet oxidation offers a new opportunity for the improvement of the quality of wastewater designated for discharge or recycling. First of all, the utilization of coagulated sludge via wet oxidation provides a conditioning process for the sludge, i.e. dewatering, which is rather difficult to carry out with untreated waste. Secondly, Fe2(SO4)3, which is employed earlier as a coagulant, transforms the conventional wet oxidation process into a catalytic one. The use of coagulation as the post-treatment for wet oxidation can offer the possibility of the brown hue that usually accompanies the partial oxidation to be reduced. As a result, the supernatant is less colored and also contains a rather low amount of Fe ions to beconsidered for recycling inside mills. The thickened part that consists of metal ions is then recycled back to the wet oxidation system. It was also observed that wet oxidation is favorable for the degradation of pitch substances (LWEs) and lignin that are present in the process waters of paper mills. Rather low operating temperatures are needed for wet oxidation in order to destruct LWEs. The oxidation in the alkaline media provides not only the faster elimination of pitch and lignin but also significantly improves the biodegradable characteristics of wastewater that contains lignin and pitch substances. During the course of the kinetic studies, a model, which can predict the enhancements of the biodegradability of wastewater, was elaborated. The model includes lumped concentrations suchas the chemical oxygen demand and biochemical oxygen demand and reflects a generalized reaction network of oxidative transformations. Later developments incorporated a new lump, the immediately available biochemical oxygen demand, which increased the fidelity of the predictions made by the model. Since changes in biodegradability occur simultaneously with the destruction of LWEs, an attempt was made to combine these two facts for modeling purposes.

Kalvoerotusprosessin esikäsittely

Työn tavoitteena oli tutkia kiertoveden puhdistamiseen käytetyn kalvosuodatuksen esikäsittelymenetelmien vaikutusta ultrasuodatukseen. Suodatettava vesi oli kierrätyskuitua käyttävän paperikoneen kiekkosuotimen kirkassuodosta. Koeajon loppuosassa käytettiin biokirkassuodosta. Paperitehtaassa oli suljettu vesikierto. Pilot-laitteistona käytettiin Metso PaperChemin OptiFilter CR550/40 ultrasuodatusyksikköä. Testatut kalvot olivat C30 kalvoja. Suodatuksissa seurattiin esikäsittelymenetelmien vaikutusta permeaatin määrään ja laatuun. Ultrasuodatus tehtiin sekä ilman esikäsittelyä että lamelliselkeytin esikäsittelynä. Esikäsittelykemikaalina käytettiin talkkia. Ultrasuodatuksissa havaittiin, että suodatuslämpötilalla oli suora vaikutus kapasiteettiin. Lämpötila vaikutti lineaarisesti kirkassuodoksen ja biokirkassuodoksen permeaattivuohon. Lämpötila nostettiin 55oC:een suodatuslämpötilasta 35 – 40oC. Korkeassa lämpötilassa kirkassuodos oli kapasiteetiltaan suurempi kuin biokirkassuodos. Konsentrointiajoista nähtiin, että ultrasuodatuksen syötön konsentraatioaste vaikutti kirkassuodoksen permeaattivuohon. Syötön konsentraatioastetta lisättäessä kapasiteetti laski. Konsentrointiajoja vertailtaessa havaitaan, että ilman esikäsittelyä vuo laski konsentroitaessa nopeammin kuin suodatuksissa, joissa käytettiin esikäsittelyä. Lamelliselkeyttimellä ja talkilla esikäsitelty suodatus laski kapasiteettia vähiten. Konsentraatioasteen nostaminen lisäsi konsentraatin kemiallista hapenkulutusta. Konsentraatin viskositeetti nousi konsentraatioastetta lisättäessä. Analyysitulosten perusteella saadaan ultrasuodatuskalvoille tyypilliset reduktiot. COD-reduktio oli 10 – 30 %, anionisuuden 40 – 70 % ja värin 80 – 90 %. Vuon kanssa korreloivat pH, uuteaine, ligniini, viskositeetti ja hemiselluloosat.

Jätevedenpuhdistamon toiminnan optimointi

Schauman Wood Oy Pelloksen tehtaat on Euroopan suurin havuvanerin valmistaja. Tehtailla tukkien haudonnassa ja kuorien kuivaamisessa syntyvät jätevedet sekä sosiaalijätevedet puhdistetaan omassa biologisessa puhdistamossa. Puhdistamo rakennettiin alun perin aktiivilietelaitokseksi ja muutettiin kuormituksen kasvaessa vuonna 2002 kantoaineprosessiksi. Puhdistamolle laskettiin ensin optimaalinen kuormitus, jonka perusteella kuormitusta ryhdyttiin nostamaan. Tavoitteena oli saavuttaa virtaaman nostolla ja ajomallien muutoksilla tilavuuskuorma 1-3 kgBOD/m3•d. Kun tulovirtaamaa oli saatu nostettua riittävästi, tehtiin laskeutuskokeita laskeutuskemikaalin optimimäärän selvittämiseksi. Koeajojakson lopuksi pidettiin kolmen viikon tehotarkkailujakso, jolloin kokeiltiin puhdistamon ajoa erilaisilla kemikaalimäärillä. Näin saatiin selville tasemielessä tietyn puumäärän aiheuttama kuormitus puhdistamolle. Jätevedenpuhdistamon tulovirtaama saatiin nostettua tasolle 300- 350 m³/d, jolloin tilaavuuskuormaksi tuli 1,68 kgBOD/m3•d. Kolmen viikon tehotarkkailujakson aikana saatiin selvitettyä optimikemikaaliannostus sekä laskettua kolmesta eri vaihtoehdosta taloudellisesti kannattavin ajomalli. Puhdistusreduktioiden, puhdistamon toimivuuden ja taloudellisuuden kannalta paras vaihtoehto oli laskeutuskemikaalin ja polymeerin yhteiskäyttö.

Treatment of micropollutants in municipal wastewater: study of a sequential batch biofilter

All the experimental part of this final project was done at Laboratoire de Biotechnologie Environnementale (LBE) from the École Polytechnique Fédérale de Lausanne (EPFL), Switzerland, during 6 months (November 2013- May 2014). A fungal biofilter composed of woodchips was designed in order to remove micropollutants from the effluents of waste water treatment plants. Two fungi were tested: Pleurotus ostreatus and Trametes versicolor in order to evaluate their efficiency for the removal of two micropollutants: the anti-inflammatory drug naproxen and the antibiotic sulfamethoxazole,. Although Trametes versicolor was able to degrade quickly naproxen, this fungus was not any more active after one week of operation in the filter. Pleurotus ostreatus was, on contrary, able to survive more than 3 months in the filter, showing good removal efficiencies of naproxen and sulfamethoxazole during all this period, in tap water but also in real treated municipal wastewater. Several other experiments have provided insight on the removal mechanisms of these micropollutants in the fungal biofilter (degradation and adsorption) and also allowed to model the removal trend. Fungal treatment with Pleurotus ostreatus grown on wood substrates appeared to be a promising solution to improve micropollutants removal in wastewater.