TREATMENT OF LANDFILL LEACHATE IN SBR SYSTEMS: ANALYSIS OF BIOMASS ACTIVITY BY MEANS OF RESPIROMETRIC TECHNIQUES

In the last decades landfilling has been the main method of municipal solid waste (MSW) disposal in many countries. MSW landfills are usually considered as a large biological reactor where the MSWs undergo anaerobic digestion producing gas and liquid emissions. Aged, or mature leachate, which is produced by older landfills, can be very refractory; for this reason mature leachate is difficult to treat alone, but it can be co-treated with sewage or domestic wastewater. The aim of the study was to investigate the feasibility of co-treatment of landfill leachate and synthetic wastewater in different percentages, in terms of process performance and biomass activity, by means of respirometric techniques. Two sequencing batch reactors (SBR) were fed with synthetic wastewater and different percentages of landfill leachate (respectively 10% and 50% V/V in SBR1 and SBR2). The obtained results showed a good organic carbon removal efficiency for both reactors; ammonia removal efficiency showed different trends between SBR1 and SBR2, probably due to inhibition factors exerted by high landfill leachate percentage present in SBR2

Greenhouse gases from membrane bioreactor treating hydrocarbon and saline wastewater

The effect of wastewater salinity and presence of petroleum hydrocarbon on N2O emission was investigated in a membrane bioreactor, in which the anoxic and aerobic zones were put in series according to a pre-denitrification scheme. The pilot plant, was continuously fed by a mixture of real and synthetic wastewater. It was operated with a first phase of acclimation of the biomass to a given salinity by gradually increasing the salt concentration from 10 gNaCl/L to 20 gNaCl/L, and to a second phase of petroleum hydrocarbon dosing at 2 g/L (as gasoline). The first phase revealed a clear relationship between nitrous oxide emissions and salinity due to the increased NO2-N production caused by the stress induced both on autotrophic and heterotrophic biomass by the increased salinity. However, after 45 days of operation, the growth rate of the autotrophic species started to recover, indicating acclimatization of the nitrifiers. In the second phase, the hydrocarbon shock induced a temporary complete inhibition of the biological activities, as well as the temporary suppression of the N2O emissions. The observations in this study revealed that the oxic tank is the major source in terms of nitrous oxide emission flux. Indeed the aerobic tank emitted 1 or 2 order of magnitude more than the anoxic one. The reason of this is likely due to the stripping of the gas by aeration

Simultaneous nitritation-denitritation for the treatment of high-strength nitrogen in hypersaline wastewater by aerobic granular sludge

Fish processing industries produce wastewater containing high amount of salt, organic matter and nitrogen. Biological treatment of such wastewaters could be problematic due to inhibitory effects exerted by high salinity level. In detail, as is known, high salt concentration leads to accumulation of nitrite due to inhibition of nitrite-oxidizing bacteria. The feasibility of performing simultaneous nitritation and denitritation in treating of fish canning wastewater by aerobic granular sludge was evaluated, and simultaneous nitritation-denitritation was successfully sustained up to 50 gNaCl L-1. Nitritation collapsed above which nitritation, and the only nitrogen removal mechanism was represented by heterotrophic synthesis. Conversely, organic matter removal was not affected by salinity, but rather by organic loading rate (OLR). COD fractionation analysis highlighted that aerobic granules exhibited excellent removal capacity toward particulate organic matter. Finally, results obtained in this work pointed out that aerobic granular sludge had excellent ability of adapting in adverse environmental conditions

Endurance training: Is it bad for you?

Endurance exercise training exerts many positive effects on health, including improved metabolism, reduction of cardiovascular risk, and reduced all-cause and cardiovascular mortality. Intense endurance exercise causes mild epithelial injury and inflammation in the airways, but does not appear to exert detrimental effects on respiratory health or bronchial reactivity in recreational/ non-elite athletes. Conversely, elite athletes of both summer and winter sports show increased susceptibility to development of asthma, possibly related to environmental exposures to allergens or poor conditioning of inspired air, so that a distinct phenotype of “sports asthma” has been proposed to characterise such athletes, who more often practise aquatic and winter sports. Overall, endurance training is good for health but may become deleterious when performed at high intensity or volume

Respirometric assessment of heterotrophic and autotrophic biomass activity in alternate oxic-anoxic MBR pilot plant

The paper reports the main results of an experimental study carried out on a Membrane Biological Reactor (MBR) pilot plant characterized by intermittent aeration. The effect of different aeration/non aeration ratio (TA/TNA) on biomass behavior, in terms of heterotrophic and autotrophic kinetic parameters and active biomass fraction, was studied. Moreover was proposed a method to evaluate the autotrophic active fraction, derived by a combination of the ASM1 model and biokinetic parameters directly evaluated by means of respirometry. The experimental observation outlined that TA/TNA in the cycle didn’t affect heterotrophic biomass kinetic and active fraction. This one instead, resulted strongly depended from the soluble substrate present in the influent wastewater. Furthermore, it was observed that a higher aerated phase within the cycle, may lead to a higher autotrophic biomass active fraction

Comparison between MBR and MB-MBR pilot plants subject to a gradual salinity increase: analysis of biokinetic and fouling behaviour

Two pilot plants were investigated for the treatment of wastewater subject to a gradual increase of salinity. In particular, a membrane bioreactor (MBR) and a moving bed biofilm membrane bioreactor (MB-MBR) were studied. Carbon and ammonium removal, kinetic constants and membranes fouling rates have been assessed. Both plants showed very high efficiency in terms of carbon and ammonium removal and the gradual salinity increase led to a good acclimation of the biomass, as confirmed by the respirometric tests. Significant biofilm detachments from carriers were experienced, which contributed to increase the irreversible superficial cake deposition. However, this aspect prevented the pore fouling tendency in the membrane module of MB-MBR system. On the contrary, the MBR pilot, even showing a lower irreversible cake deposition, was characterized by a higher pore fouling tendency

Evaluación de una población de Sorghastrum pellitum (Hack.) Parodi hasta su reintroducción en áreas medanosas

In natural areas, the changes produced by fence and selective grazing of cattle led to the loss of some species and increasing others. Sorghastrum pellitum (red grass), fodder pasture important, has been virtually eliminated or reduced to marginal areas due to livestock use. The aim of this study was to evaluate the behavior of this species from seed germination and during a year of plant development. In spring 400 plants were established in field and their development was evaluated in this growing season. The results indicate a high sensitivity of seedlings to low temperatures. Once seedling stage past, the plants showed a good development with growth even in periods of low rainfall.En áreas de pastizales naturales, las modificaciones producidas por el apotreramiento y el pastoreo selectivo del ganado vacuno indujeron a la pérdida de algunas especies y el incremento de otras. Sorghastrum pellitum (pasto colorado o pasto vaca), forrajera estival importante del pastizal sammófilo, ha sido prácticamente eliminada o reducida a áreas marginales debido al uso ganadero. El objetivo de este trabajo fue evaluar el comportamiento de esta especie desde la germinación de los cariopsis y durante la primera estación de crecimiento de las plantas, especialmente su tolerancia a heladas. Mediante experiencias en condiciones semicontroladas se pretendió predecir sus aptitudes para la reintroducción. En invernáculo se evaluó el poder germinativo de los cariopsis, la emergencia y el crecimiento inicial de las plántulas. En primavera se realizó el transplante de 400 individuos a campo y se evaluó su desarrollo durante el primer ciclo vegetativo. Los resultados obtenidos indican una gran sensibilidad de las plántulas a las bajas temperaturas. Superada la etapa de plántula se observó un buen desarrollo a campo con crecimiento aún en períodos de escasas precipitaciones

Dinámica de un arbustal de jarilla (Larrea divaricata cav.) luego de un incendio en el Parque Nacional Lihue Calel, La Pampa

The values of green biomass (Bv) measured in a grassland were associated with index values of normalized difference vegetation index (NDVI) from satellite data in three relict natural grassland on stream Chucul, from his beginning site 1 (32° 49'21, 0`` S and 64° 24 `07.0 `` W) until its demise in plain area: site 3 (33° 06` 25.5 `` S and 63° 32 `49.1 `` W). Under the hypothesis of correspondence of Bv and data obtained by images, the aim of this work is to determine the relationship between measured field data and satellite data in natural grasslands. Seasonally during the 2009-2011 cycle were sampled at random with 10 replicates of 0.25 m2 recording floristic list. To determine Bv in each plot the biomass was cut and separated in green and dry compartments and dryed to constant weight. For digital analysis bands 3 and 4 of Landsat 5 TM image (Path 228 Row 083) were used for each site close to the sampling date. The highest values of green biomass were determined for site 3, in December 2011: 189.6 g/m2 and in March for sites 1 and 2: 105.74 and 115.22 g/m2. Among all the observed values of biomass and NDVI estimated the correlation coefficient was highest at site 3 (R = 0.50). The results of the work for site 3 validate the hypothesis and indicats of the aptitude of digital images for study the status and changes in vegetation.En los ecosistemas semiáridos, las comunidades vegetales han evolucionado en presencia de fuegos frecuentes. Eso hace que muchas especies, hayan desarrollado mecanismos que les permiten tolerar su acción. En el Parque Nacional Lihué Calel, La Pampa, Argentina, a fines del año 2003, se produjo un incendio, que modificó la composición y estructura de las comunidades de arbustales de jarilla (Larrea spp.), presentes en las áreas afectadas. El objetivo de este estudio fue evaluar la dinámica post incendio de distintas áreas afectadas según la quema haya sido intensa y leve. Se trabajó además con un control no quemado. Los estudios fueron realizados al año (2005) y a los 4 años de producidos el incendio (2008). Se realizaron evaluaciones de abundancia-cobertura de vegetación (N=12). Además, se tomaron muestras compuestas de suelo al azar (N=16) para determinar carbono orgánico total, materia orgánica y textura. Por efecto del incendio, se produjeron modificaciones estructurales en la comunidad. En las áreas más intensamente quemadas se produjo un reemplazo de la jarilla por especies espinosas. En cuanto a las características del suelo, donde la intensidad del incendio fue leve, las variables edáficas no tuvieron cambios. En las áreas de quema intensa se observó un incremento de la fracción arena, además de cambios florísticos significativos

La denitrificazione biologica delle acque di falda: studio di tre differenti substrati organici

L’uso massiccio di fertilizzanti contenenti azoto è causa dei fenomeni di inquinamento diffuso delle acque di falda. In tale ottica, notevole interesse hanno recentemente riscosso i trattamenti biologici in situ, in grado di promuovere la denitrificazione delle acque di falda mediante la realizzazione di interventi che coniugano efficacia di rimozione e costi relativamente contenuti. Nella nota si riportano i risultati di una ricerca sul processo di denitrificazione eterotrofa, condotta utilizzando come fonte di carbonio tre materiali convenzionalmente considerati di scarto: corteccia di pino, sughero e sansa di olive. Lo studio è stato suddiviso in due fasi: la prima condotta in modalità batch, che ha consentito di valutare le caratteristiche dei substrati utilizzati e l’effettiva capacità di biodegradazione; la seconda condotta su impianti lab-scale in colonna, funzionanti in continuo, che ha consentito di verificare l’effettiva resa degli interventi proposti. Sono state comparate le differenti capacità di rilascio di carbonio organico e le efficienze di denitrificazione conseguibili coi materiali utilizzati. I risultati ottenuti hanno mostrato buoni rendimenti di rimozione, evidenziando sostanziali differenze delle cinetiche di processo tra i vari substrati; in particolare, è risultato che la sansa di olive è il materiale che garantisce le migliori performance di denitrificazione.The intensive use of nitrogen based fertilizers represents the main cause of diffused pollution in groundwater. For this reason, in situ biological groundwater denitrification, coupling good removal efficiency and low operational cost, have obtained up to nowadays an increasing interest from researchers communities. The paper reports the results of a lab-scale investigation, concerning the heterotrophic biological denitrification, sustained by three different carbon source: pine bark, cork and olive pomace. The experimentation has been divided into two phases: the former, focused to investigates the carbon sources features as well as the effective biodegradation capability, carried up in batch; the second carried out by means of lab-scale column continuously fed by water artificially contaminated with nitrates. The achieved results have shown good removal efficiency and also significant differences in kinetics have been highlighted. Particularly, olive pomace was the organic substrate capable to promote the best denitrification performances

Test in colonna per la denitrificazione delle acque di falda: studio del comportamento di tre differenti substrati organici

Il crescente impiego di fertilizzanti contenenti azoto ha avuto come effetto l'accumulo di nitrati nelle acque di falda. A causa della natura diffusa delle sorgenti di contaminazione, la necessità di individuare interventi di risanamento a basso costo e che richiedano attività gestionali ridotte è diventata prioritaria. In tale ottica, notevole interesse hanno recentemente riscosso i trattamenti biologici in situ, in grado di promuovere le denitrificazione delle acque di falda mediante la realizzazione di biobarriere. Nella nota vengono riportati i risultati di una ricerca sul processo di denitrificazione eterotrofa promosso utilizzando come fonte di carbonio tre materiali convenzionalmente considerati di scarto: corteccia di pino, sughero e sansa di olive. Test in colonna sono stati effettuati per un periodo di 200 giorni, al fine di osservare il processo di denitrificazione stimolato dai substrati prescelti; i risultati ottenuti alimentando acqua artificialmente contaminata di nitrati hanno mostrato buoni rendimenti di rimozione, evidenziando sostanziali differenze delle cinetiche di processo tra i vari substrati