Search

Wastewater source-separation and on-site treatment systems face severe problems of wastewater availability. Therefore, the effect of repeated short-term starvation and reactivation periods on a partial nitritation-anammox (PN/AMX) based process was assessed treating digested blackwater at room temperature. First, two sequencing batch reactors (SBR) were operated in continuous mode (SBR-C, which served as control) and with repeated starvation/reactivation periods during the nights and the weekends (SBR-D), using simulated blackwater (300 mg N/L and 200 mg COD/L) as substrate. The results showed no remarkable difference in overall process performance between both reactors, achieving total nitrogen removal efficiencies (NRE) around 90 %. Furthermore, no significant variations were measured in specific activities, except for the aerobic heterotrophic one that was lower in SBR-D, presumably due to the exposure to anoxic conditions. Then, the technical feasibility of applying the PN/AMX system to treat real blackwater produced in an office building during working hours was successfully proved in a third reactor (SBR-R), with the same starvation/reactivation periods tested in SBR-D. Despite the low temperature, ranging from 14 to 21 °C, total NRE up to 95 % and total nitrogen concentration in the effluent lower than 10 mg N/L were achieved. Moreover, a good recovery of the PN/AMX process performance after a long starvation period of 15 days (simulating holidays) was observed. Results proved for the first time the feasibility and long-term stability (100 days) of the PN/AMX process for the treatment (and potential reuse) of blackwater in a decentralized system, with repeated starvation/reactivation periods and after long starvation.

In this study, plastics industry wastewater (PIWW) characterized by high total and soluble chemical oxygen demand (tCOD and sCOD, up to ~2200 and ~1500 mg/L, respectively) and remarkable unbiodegradable soluble COD (usCOD, 508±224 mg/L, 31±14% of tCOD) concentrations was treated at laboratory scale using a hybrid moving bed biofilm reactor (MBBR). Interestingly, the MBBR showed average tCOD, sCOD and usCOD removal efficiencies of 26±6, 32±11 and 36±11%, respectively, which were comparable to those achieved by the coagulation/flocculation pre-treatment currently applied at full-scale. Such results encourage the application of MBBR as a cost-effective option for the removal of recalcitrant soluble organics from PIWW and other similar industrial wastewaters.

In this study, continuous measurements of nitrous oxide gaseous emissions from a lab-scale partial nitritation (PN) chemostat treating ammonium-rich (1500 mgN/L) synthetic wastewater were performed, in order to achieve a deeper knowledge about its potential environmental impact. The reactor was operated at constant hydraulic retention time (HRT, 1 d) and nitrogen loading rate (NLR, 1500 mgN/L·d), with different influent alkalinity/nitrogen molar ratios (alk/N, 1 and 1.3) and dissolved oxygen concentrations (DO, 5.0, 3.0, 2.0, 1.5 and 1.0 mgO2/L). As DO ranged between 5.0 and 1.5 mgO2/L, the partial conversion of ammonium to nitrite was successfully achieved, with a negligible production of nitrate and nitrous oxide. When alk/N was increased from 1 to 1.3 (DO was not limiting, i.e. 2 mgO2/L), the increase in ammonium-nitrogen removal rate (ANRR, from 717±17 to 945±21 mgNH4-N/L·d) and the simultaneous decrease in specific N2O-N production (from 0.33±0.01 to 0.23±0.01% of ANRR) were observed. When DO was set to 1.0 mgO2/L, partial nitritation was irreversibly compromised, and a corresponding increase in specific N2O-N production was observed (from 0.22±0.01 to 0.61±0.03% of ANRR). The results indicate a clear correlation between N2O production and autotrophic ammonium to nitrite oxidation rate.

The combination of partial nitritation and anammox (anaerobic ammonium oxidation) has been mainly applied to the treatment of wastewaters with high ammonium concentration and low content of biodegradable organic carbon. So far, only few studies have focused on the application of partial nitritation-anammox process to the treatment of ammonium-rich wastewaters characterized also by a high organic carbon to nitrogen ratio (Corg/N), as well as by the presence of toxic substances: in this study, an anammox reactor was started-up and fed with the effluent from a partial nitritation reactor treating IGCC (Integrated Gasification Combined Cycle) wastewater, in order to evaluate its feasibility as an alternative to the currently applied chemical-physical-biological treatment. A sequencing batch reactor was inoculated with granular anammox biomass and run at controlled temperature (35±0.5 °C) and pH (7.7±0.3). The synthetic influent containing NH4-N (up to 250 mg/L) and NO2-N (up to 330 mg/L) was progressively replaced by the IGCC wastewater, which had been pre-treated in the lab-scale partial nitritation reactor. When the reactor was fed with the synthetic medium at the target nitrogen loading rate (NLR, 0.350 gN/L?d), the observed NH4-N removal efficiency was 93±5%, and no nitrite was detected in the effluent. Good overall process performance was maintained as increasing amounts (up to 65%) of the effluent from the partial nitritation system were fed to the anammox reactor: NH4-N and NO2-N removal efficiencies were 98.9±1.0% and 96.6±2.1%, respectively, and nitrite specific removal rate peaked at 0.28 gNO2-N/gVSS?d. On day 154, a nitrogen shock load was applied to evaluate anammox stability during start-up: despite system sensitivity to the sudden increase of nitrogen load, process performance was recovered and the percentage of IGCC wastewater in the influent could be raised to 100% with fairly good NH4-N and NO2-N removal efficiencies (85.7±5.8% and 88.2±2.3%, respectively). Anammox granules were compact (diameter, 0.636±0.02 mm) and dense (86.5±3.4 gTSS/Lgran), with good settling properties. The total organic carbon (TOC) removal efficiency was low: since most of TOC (around 80±8%) had been removed in the preliminary partial nitritation step (results not shown), it can be assumed that the residual TOC entering the anammox reactor was slowly biodegradable, therefore heterotrophic denitrifiers did not compete with anammox biomass for nitrite. The results indicate that anammox start-up can be successfully achieved and the process can be applied in combination with a preliminary partial nitritation step for the treatment of ammonium-rich IGCC wastewater, thus providing useful information also for the treatment of similar wastewaters with high Corg/N ratio and containing toxic substances.

Con il termine “sviluppo” ci riferiamo fondamentalmente all’insieme degli eventi attraverso cui da un uovo fecondato si genera un organismo pluricellulare, composto da differenti tipi cellulari, organizzati in tessuti ed organi, ciascuno deputato a svolgere una specifica funzione (di sostegno, di protezione, di nutrizione, di locomozione, sensoriale, riproduttiva, ecc.) e con una sua ben precisa forma tridimensionale e localizzazione spaziale rispetto alle altre strutture che compongono l’organismo.

Within-field variability in the Fusarium head blight (FHB) and its associated mycotoxins was studied in four European countries. At each of 14 sites, each FHB pathogen and associated mycotoxins were quantified in 16 quadrat samples at harvest. Overall, the incidence of quadrat samples with detectable and quantifiable pathogen DNA was significantly lower in the grain than in the corresponding chaff. Deoxynivalenol (DON) was the most frequently detected toxin in the samples and its accumulation was most strongly associated with the presence of Fusarium graminearum. Nivalenol (NIV) accumulation was significantly associated only with the presence of F. culmorum. Zearalenone (ZON) accumulation was strongly associated with the presence of all three pathogens (F. graminearum, F. culmorum and F. poae). The levels of both DON and ZON concentrations were positively related to the amount of F. graminearum DNA in the grain or in the chaff. The presence/absence of FHB pathogens within a single quadrat appeared to be independent of each other. The presence of a particular FHB pathogen and the amount of its DNA, as well as the associated mycotoxin(s), varied greatly among samples at each site. This study demonstrated the large extent of within-field variability of FHB and its associated mycotoxins, and the importance of representative sampling in FHB studies.

Cultures of schwalla cells froill ncoaatal rat sciatic aenes ivere treated with acety1cholilic agonists tvid the cjj cts oil cell Prolificratiou cniluatcd. 3[HI-thyaiidiac incorporation shows that accty1choliac (ACh) receptor agoiiists ilillibit cell proliftratioti, aiid FACS analysis deinoustratcs ccll-cyclc arrest and accunlulatioii of cells ill the Gi phase. The use of arecaiditie, a selective agouist of niuscariiiic M2 receptors reveals that this effect depends nictitily oil jW2 receptor acth,atioii. The arecaidine i1cpetialci i t- block ill Gi is rci,ersible becausc reinoval of arecaidiue froai the culture iiieditaii mduccs progrcssioil to the S phase. The block of the Gj-S transitioil is also characterized by inodulatiou of the expressioti ofscwrol cell-cycic inarkcrs. Morcoi,cr, trcatnicat ivith ACh receptor agmist causes both a decreasc ill the PCNA prolcin lci,cls ill Schivaiiii cell iniclci aad all iiicreasc ill P27 Olld P53 proteins. Filially, iinnnuio-elcctrou inicroscopy dcalonStl-atCS that M2 receptors arc expressed by Schivanii cells ill i,ivo. These results inclicate that ACh, by aiodulatiiig Schwaiin cell prolificratioii through M2 I-CCCPtOl- aclivatioa,)iiight cowributc to their progression to a niore dif rewiated phenotype.

Two years of field sampling aimed to establish the predominance and association among the fungal pathogens causing Fusarium ear blight (FEB) in four European countries (Hungary, Ireland, Italy and the UK). A PCR-based method was used to detect four Fusarium species and two varieties of Microdochium nivale present in the samples. The prevalence of FEB pathogens differed significantly between countries. Overall, all pathogens were commonly detected in Ireland and to a lesser extent in the UK. In contrast, only two species, F. graminearum and F. poae, were regularly detected in Italy and Hungary. Fusarium culmorum was rarely detected except in Ireland. Log-linear models were used to determine whether there is the independence of the six FEB pathogens at each sampling site. Significant two-pathogen interactions were frequently observed, particularly in harvest samples; all these significant two-pathogen interactions were of the synergistic type, except between F. poae and F. culmorum, and were generally consistent over the 2 years and four countries. Fusarium graminearum and F. poae were least frequently involved in two pathogen interactions but were involved in most of the nine significant three-pathogen interactions. However, only the interaction between F. graminearum, F. avenaceum and F. poae was significant in both years. Potential implications of the present results in FEB management are discussed

Neurological impairment is a common feature of Acquired Immunodeficiency Syndrome (AIDS); functional alterations have been reported both in central and peripheral nervous system and the Human Immunodeficiency Virus (HIV) envelope glycoprotein gp120 has been proposed as a neurotoxin acting through a calcium-dependent mechanism. On the other hand it has been reported that gp120 treatment also induce about a 20% decrease in the cerebral glucose utilization and in the cellular ATP levels. The reported observations were performed on experimental system where also non-neuronal cells where present; in order to evaluate whether a direct interaction between HIV proteins and neuronal cells takes place, we used a neuroblastoma cultures where only neuronal cells are present. We analysed the effects of gp120 on the N18TG2 neuroblastoma clone. Treatments were performed both on growing and confluent cultures. Short time treatment with gp120 of confluent cultures causes a 25% reduction in the level of neuron-specific enolase, resulting in a similar decrease of oxygen consumption. Long time exposure of growing cells also causes a reduction in cell survival. Furthermore, using a membrane-specific fluorescent probe we observed that gp120 produces an increase of membrane trafficking. These observations suggest a direct interaction between the viral envelope protein and neuronal cells, which results in an alteration of glycolytic metabolism. This alteration may be related to the neurologic impairments observed in AIDS patients.