Grey water treatment at a sports centre for reuse in irrigation: a case study.

Grey water has long been considered a promising option for dealing with water scarcity and reuse. However, factors such as lack of macronutrients and low carbon content make its treatment challenging. The aim of this paper was to investigate the applicability of sequencing batch reactor (SBR) technology to on-site grey water treatment at a sports centre for reuse in irrigation. The results demonstrated that the regenerated water complied with microbiological parameters concerning restriction of solids and organic matter removal. Denitrification was not fully accomplished, but ammonium was totally oxidised and low concentrations of nitrates were achieved. Effluent with good appearance and no odour was used in an experimental study to irrigate a grid system containing natural and artificial grass sections. The conclusion is that SBR technology offers a promising treatment for grey water.

Combining partial nitritation and heterotrophic denitritation for the treatment of landfill leachate previous to an anammox reactor.

Landfill leachate can present extremely elevated concentrations of ammonium (up to 6,000 mg N-NH(4) (+) L(-1)) and a low biodegradable organic matter fraction. As an alternative to conventional systems, this wastewater can be treated on a more sustainable way by a fully autotrophic partial nitritation-anammox system. The operation of the first step of this system, the partial nitritation, is critical since the elevated concentrations of ammonium and nitrite in the reactor can severely inhibit ammonium oxidizing bacteria (AOB) activity. In this way, the inclusion of anoxic phases during the feeding events to promote the denitrification via nitrite can be a good option for upgrading the process performance and increasing the stability of the system. This paper deals with the evaluation of an anoxic-aerobic step-feed strategy for the operation of a partial nitritation SBR. Results of this study have revealed a decrease on the total nitrogen inside the reactor of more than 200 mg N L(-1) without prejudice on the partial nitritation process. Furthermore, this study has also allowed detecting an AOB activity reduction at the end of aerobic phases due to bicarbonate limitation and/or free nitrous acid inhibition.

Managing your boss: a compatible relationship with your superior is essential to being effective in your job.

Good managers recognize that a relationship with a boss involves mutual dependence and that, if it is not managed well, they cannot be effective in their jobs. They also recognize that the boss-subordinate relationship is not like the one between a parent and a child, in that the burden for managing the relationship should not and cannot fall entirely on the boss. Bosses are only human; their wisdom and maturity are not always greater than their subordinates'. Effective managers see managing the relationship with the boss as part of their job. As a result, they take time and energy to develop a relationship that is consonant with both persons' styles and assets and that meets the most critical needs of each.

Anoxic phases are the main N2O contributor in partial nitritation reactors treating high nitrogen loads with alternate aeration.

Partial nitritation (PN) reactors treating complex industrial wastewater can be operated by alternating anoxic-aerobic phases to promote heterotrophic denitrification via NO2(-). However, denitrification under stringent conditions can lead to high N2O production. In this study, the suitability of including anoxic phases in a PN-SBR treating real industrial wastewater was assessed in terms of process performance and N2O production. The PN-SBR was operated successfully and, when the HCO3(-):NH4(+) molar ratio was adjusted, produced a suitable effluent for a subsequent anammox reactor. 10-20% of the total influent nitrogen was removed. N2O production accounted for 3.6% of the NLR and took place mainly during the anoxic phases (60%). Specific denitrification batch tests demonstrated that, despite the availability of biodegradable COD, NO2(-) denitrification advanced at a faster rate than N2O denitrification, causing high N2O accumulation. Thus, the inclusion of anoxic phases should be avoided in PN reactors treating industrial wastewaters with high nitrogen loads.

Nitrous oxide reduction genetic potential from the microbial community of an intermittently aerated partial nitritation SBR treating mature landfill leachate.

This study investigates the microbial community dynamics in an intermittently aerated partial nitritation (PN) SBR treating landfill leachate, with emphasis to the nosZ encoding gene. PN was successfully achieved and high effluent stability and suitability for a later anammox reactor was ensured. Anoxic feedings allowed denitrifying activity in the reactor. The influent composition influenced the mixed liquor suspended solids concentration leading to variations of specific operational rates. The bacterial community was low diverse due to the stringent conditions in the reactor, and was mostly enriched by members of Betaproteobacteria and Bacteroidetes as determined by 16S rRNA sequencing from excised DGGE melting types. The qPCR analysis for nitrogen cycle-related enzymes (amoA, nirS, nirK and nosZ) demonstrated high amoA enrichment but being nirS the most relatively abundant gene. nosZ was also enriched from the seed sludge. Linear correlation was found mostly between nirS and the organic specific rates. Finally, Bacteroidetes sequenced in this study by 16S rRNA DGGE were not sequenced for nosZ DGGE, indicating that not all denitrifiers deal with complete denitrification. However, nosZ encoding gene bacteria was found during the whole experiment indicating the genetic potential to reduce N2O.

Coupling anammox and advanced oxidation-based technologies for mature landfill leachate treatment.

The aim of this study was to evaluate the suitability to couple anammox process with advanced oxidation processes (AOPs) to treat mature landfill leachate with high nitrogen and non-biodegradable organic matter concentrations (2309±96 mg N-TN L(-1) and 6200±566 mg COD L(-1)). The combination of a partial nitiration-anammox system coupled with two AOP-based technologies (coagulation/flocculation+ozonation and photo-Fenton) was assessed in terms of nitrogen and carbon removal. Total nitrogen removal efficiency within a range of 87-89% was obtained with both configurations without the need of any external carbon source. The COD removal efficiencies attained were 91% with coagulation/flocculation+ozonation and 98% with photo-Fenton. Applying the biological treatment prior to advanced oxidation processes-based technologies reduced the quantity of needed reagents giving attaining higher removal efficiencies. From a basic economical point of view and taking into account the results of this study, the combination of partial nitritation-anammox system with photo-Fenton treatment was more favorable than with coagulation/flocculation+ozonation treatment.

Effect of temperature on AOB activity of a partial nitritation SBR treating landfill leachate with extremely high nitrogen concentration.

This study investigates the effects of temperature on ammonia oxidizing bacteria activity in a partial nitritation (PN) sequencing batch reactor. Stable PN was achieved in a 250 L SBR with a minimum operating volume of 111L treating mature landfill leachate containing an ammonium concentration of around 6000 mg N-NH(4)(+)L(-1) at both 25 and 35 °C. A suitable influent to feed an anammox reactor was achieved in both cases. A kinetic model was applied to study the influence of free ammonia (FA), the free nitrous acid (FNA) inhibition, and the inorganic carbon (IC) limitation. NH(4)(+) and NO(2)(-) concentrations were similar at 25 and 35 °C experiments (about 2500 mg N-NH(4)(+)L(-1) and 3500 mg N-NO(2)(-)L(-1)), FA and FNA concentrations differed due to the strong temperature dependence. FNA was the main source of inhibition at 25 °C, while at 35 °C combined FA and FNA inhibition occurred. DGGE results demonstrated that PN-SBR sludge was enriched on the same AOB phylotypes in both experiments.

[Beyond the photodynamic diagnosis: Searching for excellence in the diagnosis of non-muscle-invasive bladder cancer]. / Más allá del diagnóstico fotodinámico: buscando la excelencia en el diagnóstico del cáncer vesical no músculo-invasivo.

Cystoscopy is gold-standard method in non muscule invasive bladder cancer diagnosis. In the cistoscopic exploratión 30% of tumors could be overlooked: it is due to a flat forms, little size tumours or difficult visualization. Photodynamic diagnosis reduces overlooked tumours rate, and has improved diagnosis on flat forms, with the consequence of increasing lap time to recurrence and decreasing the number of iterative cistoscopy; nevertheless the false positive rate is high. In the last years developed new optical devices who try to improve alone or associated diagnostic sensibility in cistoscopy without reduction of specificity. Among new devices we must emphasize some like Narrow Band Imaging, Optical Coherence Tomography or Laser Confocal Endomicroscopy.

Más allá del diagnóstico fotodinámico: buscando la excelencia en el diagnóstico del cáncer vesical no músculo-invasivo / Beyond the photodynamic diagnosis: Searching for excellence in the diagnosis of non-muscle-invasive bladder cancer

La cistoscopia es el método de elección en el diagnóstico positivo del cáncer vesical no músculo-invasivo. La tasa de tumores que pasan inadvertidos durante la cistoscopia puede llegar al 30%; esto es debido a factores como la existencia de formas tumorales planas, de pequeño tamaño o de difícil visualización. El diagnóstico fotodinámico ha conseguido disminuir la tasa de tumores que pasan inadvertidos, y ha conseguido mejorar el diagnóstico de lesiones planas; con el consiguiente aumento del tiempo libre de recidiva y disminuyendo el número de actuaciones endoscópicas iterativas; pero a costa de una tasa de falsos positivos elevada. En los últimos años se han desarrollado una serie de sistemas ópticos que pretenden; sólos o asociados; mejorar la sensibilidad diagnóstica de la cistoscopia sin menoscabo de su especificidad. Entre estos sistemas debemos destacar algúnos como Narrow Band Imaging, la Tomografía de Coherencia Óptica y la Endomicroscopía Láser Confocal (AU)

Cystoscopy is gold-standard method in non muscule invasive bladder cancer diagnosis. In the cistoscopic exploratión 30% of tumors could be overlookeed: it is due to a flat forms, litle size tumours or difficult visualization. Photodynamic diagnosis reduces overlooked tumours rate, and has improved diagnosis on flat forms, with the consequence of increasing lap time to recurrence and decrasing the number of iterative cistoscopy; nevertheless the false positive rate is high. In the last years developed new optical devices who try to improve alone or asociated diagnostic sensibility in cistoscopy whithout reduction of specificity. Among new devices we must emphasize some like Narow Band Imaging, Optical Coherence Tomography or Laser Confocal Endomicroscopy (AU)

Numerical analysis of thermal denaturation of nucleic acids.

Denaturation of DNA molecules by stepwise incrementation of the temperature leads to melting profiles showing a fine structure, composed of individual melting modes. A method is described by which quantitative physical information brought by the modes can be extracted from the melting profile. Related problems such as data editing and smoothing are also discussed.