Eloisa Pozzi - Academia.edu (original) (raw)

Papers by Eloisa Pozzi

Water Science and Technology, Oct 9, 2017

This paper shows the effect of organic shock loads (OSLs) on the anaerobic digestion (AD) of synt... more This paper shows the effect of organic shock loads (OSLs) on the anaerobic digestion (AD) of synthetic swine wastewater using an expanded granular sludge bed (EGSB) reactor modified with zeolite. Two reactors (R1 and R2), each with an effective volume of 3.04 L, were operated for 180 days at a controlled temperature of 30 C and hydraulic retention time (HRT) of 12 h. In the case of reactor 2 (R2), 120 g of zeolite was added. The reactors were operated with an up-flow velocity (v up) of 6 m/h. The evolution of pH, total Kjeldahl nitrogen (TKN), chemical oxygen demand (COD) and volatile fatty acids (VFAs) was monitored during the AD process with OSL and increases in the organic loading rate (OLR). In addition, the microbial composition and changes in the structure of the bacterial and archaeal communities were assessed. The principal results demonstrate that the presence of zeolite in an EGSB reactor provides a more stable process at higher OLRs and after applying OSL, based on both COD and VFA accumulation, which presented with significant differences. Denaturing gradient gel electrophoresis (DGGE) band profiles indicated differences in the populations of Bacteria and Archaea between the R1 and R2 reactors attributed to the presence of zeolite.

ABSTRACT A influência da contaminação aguda por metal pesado cádmio em quatro diferentes concentr... more ABSTRACT A influência da contaminação aguda por metal pesado cádmio em quatro diferentes concentrações (5, 10, 25, 100 mg Cd 2+ .L -1) na atividade metanogênica de biomassa granular em suspensão na fase líquida foi estudada em ensaios em batelada simples a 30°C. O controle foi realizado nas mesmas condições sem a adição de cádmio. Como única fonte de carbono adicional foi utilizado acetato de sódio em uma concentração de 1.280 mg O 2 .L -1 em termos de DQO. Foram analisados o pH, a remoção de matéria orgânica e, a atividade metanogênica específica (AME), além da produção de ácidos orgânicos voláteis totais, e a concentração de cádmio livre no sistema. A concentração de equilíbrio de cádmio é estabelecida rapidamente. O mecanismo de adsorção foi ajustado à isoterma de Freundlich (e iguais a 0,572 e 0,871). A cinética foi ajustada à primeira ordem, a constante cinética e o tempo de ocorrência da AME apresentam relação linear com a concentração de cádmio no adsorvente, ou seja, no caso a biomassa. O ensaio com maior concentração de cádmio apresentou um atraso temporal do início da atividade catalítica, embora todos os ensaios tenham apresentado uma boa eficiência de degradação da matéria orgânica e do substrato (acima de 90%).

Applied Biochemistry and Biotechnology, Jan 4, 2016

The effect of natural mineral on the mono-digestion of maize straw was evaluated in continuously ... more The effect of natural mineral on the mono-digestion of maize straw was evaluated in continuously stirred tank reactors (CSTRs) at 38°C. Different strategies of mineral addition were studied. The organic loading rate (OLR) was varied from 0.5 to 2.5 g volatile solid (VS) L −1 d −1. A daily addition of 1 g mineral L −1 in reactor 2 (R2) diminished the methane production by about 11 % with respect to the initial phase. However, after a gradual addition of mineral, an average methane yield of 257 NmL CH 4 g VS −1 was reached and the methane production was enhanced by 30 % with regard to R1. An increase in the frequency of mineral addition did not enhance the methane production. The archaeal community was more sensitive to the mineral than the bacterial population whose similarity stayed high between R1 and R2. Significant difference in methane yield was found for both reactors throughout the operation.

Journal of Environmental Management, Aug 1, 2014

This study used a pilot-scale submerged aerobic biofilter (SAB) to evaluate the co-treatment of d... more This study used a pilot-scale submerged aerobic biofilter (SAB) to evaluate the co-treatment of domestic wastewater and landfill leachate that was pre-treated by air stripping. The leachate tested volumetric ratios were 0, 2, and 5%. At a hydraulic retention time of 24 h, the SAB was best operated with a volumetric ratio of 2% and removed 98% of the biochemical oxygen demand (BOD), 80% of the chemical oxygen demand (COD) and dissolved organic carbon (DOC), and 90% of the total suspended solids (TSS). A proposed method, which we called the "equivalent in humic acid" (Eq.HA) approach, indicated that the hardly biodegradable organic matter in leachate was removed by partial degradation (71% of DOC Eq.HA removal). Adding leachate at a volumetric ratio of 5%, the concentration of the hardly biodegradable organic matter was decreased primarily as a result of dilution rather than biodegradation, which was confirmed by Fourier transform infrared (FTIR) spectroscopy. The total ammoniacal nitrogen (TAN) was mostly removed (90%) by nitrification, and the SAB performances at the volumetric ratios of 0 and 2% were equal. For the three tested volumetric ratios of leachate (0, 2, and 5%), the concentrations of heavy metals in the treated samples were below the local limits.

Chemosphere, Mar 1, 2006

There are few reports on morphological characterization of microbial population colonizing anaero... more There are few reports on morphological characterization of microbial population colonizing anaerobic bioreactors and the aim of this work was to access such variable in an anaerobic sequencing batch biofilm reactor treating the University of Sao Paulo (Sao Carlos city, Brazil) domestic sewage. This pilot-scale reactor (1.2 m 3) has been treating 0.65 m 3 of liquid waste under cycles of 8 h. The ASBBR has the distinct characteristics of being filled with support material for biomass attachment with the aim of skipping the sedimentation phase during the operational cycles, as it is commonly observed in anaerobic sequencing batch reactors (ASBR). Physical, chemical and physico-chemical variables were accessed in the influent and in the effluent for performance evaluation. Microbial characterization was made by means of direct microscopy and samples were taken over 150 d with a 25 d period interval. The ASBBR attained approximately 60% of COD removal efficiency. Microscopic analysis of biomass showed the presence of anoxygenic phototrophic bacteria probably influencing the ASBBR performance in the domestic sewage treatment. It is very likely that the exclusion of phototrophic sulfur bacteria by efficiently restraining the light would enhance the bioreactor efficiency.

Molecular Biology Reports, Jul 26, 2019

A microbial community was enriched in the anoxic compartment of a pilot-scale bioreactor that was... more A microbial community was enriched in the anoxic compartment of a pilot-scale bioreactor that was operated for 180 days, fed with sewage and designed for organic matter, nitrogen and sulfide removal by coupling anaerobic digestion, nitrification and mixotrophic denitrification. Denitrification occurred with endogenous electron donors, mainly sulfide and residual organic matter, coming from the anaerobic compartment. The microorganisms involved in denitrification with sulfide as electron donor were identified by DNA-stable isotope probing with [U-13 C]-labelled CO 2 and NaHCO 3. Complete denitrification occurred every two days, and the applied NO 3 − /S 2− ratio was 1.6. Bacteria belonging to the Sulfurimonas denitrificans was identified as a chemoautotrophic denitrifier, and those related to Georgfuchisa toluolica, Geothrix fermentans and Ferritrophicum radicicola were most probably associated with heterotrophic denitrification using endogenous cells and/ or intermediate metabolites. This study showed that DNA-SIP was a suitable technique to identify the active microbiota involved in sulfide-driven denitrification in a complex environment, which may contribute to improve design and operation of bioreactors aiming for carbon-nitrogen-sulfur removal.

Water Science and Technology, Sep 26, 2015

This paper assesses a wastewater treatment plant (WWTP) regarding the technology used, as well as... more This paper assesses a wastewater treatment plant (WWTP) regarding the technology used, as well as organic matter and nutrient removal efficiencies aiming to optimize the treatment processes involved and wastewater reclamation. The WWTP consists of a dissolved air flotation (DAF) system, an upflow anaerobic sludge blanket (UASB) reactor, an aerated-facultative pond (AFP) and a chemical-DAF system. The removal efficiencies of chemical oxygen demand (COD) (97.9 ± 1.0%), biochemical oxygen demand (BOD) (98.6 ± 1.0%) and oil and grease (O&G) (91.1 ± 5.2%) at the WWTP, the nitrogen concentration of 17 ± 11 mgN-NH 3 and phosphorus concentration of 1.34 ± 0.93 mgPO 4 À3 /L in the final effluent indicate that the processes used are suitable to comply with discharge standards in water bodies. Nitrification and denitrification tests conducted using biomass collected at three AFP points indicated that nitrification and denitrification could take place in the pond.

Journal of water process engineering, Jun 1, 2018

Landfill leachate is one of the major problems generated from waste; it has high concentrations o... more Landfill leachate is one of the major problems generated from waste; it has high concentrations of biodegradable and refractory organic and inorganic matter such as ammonia and heavy metals. The combined treatment of leachate with sewage has been used in various sewage treatment plants in the world. However, there are still many questions and uncertainties about the process, especially the effects of adding leachate to the treatment system. In this context, the objective of this work is to evaluate the efficiency of combined leachate/sewage treatment in activated sludge under different conditions. Treatability experiments were carried out using a bench scale (SBR) process using the volumetric proportions of 0 (control), 2 and 5% leachate under different experimental conditions. Experiment 2 (leachate pre-treated by alkalinization and air stripping) was technically more feasible, achieving removal efficiencies of BOD, COD and DOC above 97%, 82%, 60%, respectively, and the highest diversity indices of the bacterial and eukaryotic communities and flake structure stability were observed up to a volumetric ratio of 2% of pre-treated leachate. The DGGE technique used showed that populations of eukaryotes were apparently the most affected with increasing proportions of 2%-5% of the mixture, mainly for experiments 3 (B3R2) and 4 (B4R4), where the lowest diversity indices of these populations were found.

Journal of water process engineering, Jun 1, 2016

Abstract This study evaluates the microbial community involved in autotrophic denitrification by ... more Abstract This study evaluates the microbial community involved in autotrophic denitrification by sulfide oxidation, applied in the post-treatment of anaerobic effluent. The enrichment of the bacterial community and autotrophic denitrifying community was performed with biomass samples collected from a vertical fixed bed reactor operated under the following condition: autotrophic nitrate reduction with excess sulfide. The nitrate reduction condition with N/S ratio of 0.8 showed the highest concentration of autotrophic denitrifying microorganisms. The isolated bacterium was identified as Pseudomonas stutzeri - like organism. The maximum specific growth rate of the population (μmax) was 0.037 h −1 , with doubling time of 18.7 h. The cell yield (Y) was 0.15 gSSV gN −1 and denitrification rate was of approximately 0.24 gN gSSV h −1 . The data obtained point to the feasibility of applying the isolated species in the autotrophic denitrification process using sulfide as electron donor.

Journal of water process engineering, Oct 1, 2021

Abstract In Brazil, a large amount of liquid wastewater generated during orange juice production ... more Abstract In Brazil, a large amount of liquid wastewater generated during orange juice production has a significant negative impact on the citric industries. The treatment of this wastewater has been carried out in biological treatment plants. However, low organic removal efficiency has been achieved while using anaerobic or/and aerobic processes probably due to biological inhibition by toxic compounds like limonene. In this context, the objective of this study was to evaluate the limonene removal by a bench-scale horizontal-flow anaerobic immobilized biomass (HAIB) bioreactor (12L) and the transformation products formed during the applied treatment. The bioreactor was filled with three different matrices (mineral coal, polyurethane foam and gravel) containing immobilized anaerobic sludge. The used substrate contained chemical oxygen demand (COD) of 480 to 1251 mg L−1 and the concentrations of limonene ranging from 10 (period I) to 500 mg L−1 (period X) were monitored by GC–MS. The HAIB bioreactor removed organic matter (>60%), and limonene was removed with high efficiency (>95%), while operated at hydraulic retention time (HRT) of 48 and 24 h.

Brazilian Archives of Biology and Technology, Aug 1, 2012

The performance of an anaerobic sequencing-batch biofilm reactor (ASBBR-laboratory scale-14L)cont... more The performance of an anaerobic sequencing-batch biofilm reactor (ASBBR-laboratory scale-14L)containing biomass immobilized on coal was evaluated for the removal of elevated concentrations of sulfate (between 200 and 3,000 mg SO 4-2 •L-1) from industrial wastewater effluents. The ASBBR was shown to be efficient for removal of organic material (between 90% and 45%) and sulfate (between 95% and 85%). The microbiota adhering to the support medium was analyzed by amplified ribosomal DNA restriction analysis (ARDRA). The ARDRA profiles for the Bacteria and Archaea domains proved to be sensitive for the determination of microbial diversity and were consistent with the physical-chemical monitoring analysis of the reactor. At 3,000 mg SO 4-2 •L-1 , there was a reduction in the microbial diversity of both domains and also in the removal efficiencies of organic material and sulfate.

Water Air and Soil Pollution, Apr 1, 2021

This study evaluated the ecotoxicity effects of effluent from an anaerobic fixed bed biofilm reac... more This study evaluated the ecotoxicity effects of effluent from an anaerobic fixed bed biofilm reactor (AFBBR) removing the sulfamethoxazole (SMX - 403 ± 104 ng L−1) and ciprofloxacin (CIP - 294 ± 123 ng L−1) antibiotics from domestic sewage in some microorganisms (Brevundimonas sp., Escherichia coli, Ochrobactrum sp., Sphingomonas sp.) and benthic organisms (Allonais inaequalis and Chironomus sancticaroli). The AFBBR showed high removal efficiency of SMX (85 ± 10%) and CIP (81 ± 16%) and completely eliminated the acute ecotoxicological effect on the C. sancticaroli insect larvae. The bioreactor effluent did not cause any inhibition on the cell growth of the microorganisms. Nonetheless, the A. inaequalis was extremely sensitive to the reactor effluent (100% mortality), probably due to the death of bacteria and algae essential to the nutrition of the Oligochaeta. Regarding the adult insect emergency of C. sancticaroli, a reduction of 50% was observed after 17 days of exposure to the effluent with 40 μgSMX L−1, inhibiting the larval development, which did not occur for CIP. The antimicrobial inhibition by CIP present in the domestic sewage resulted in EC50 (median effective concentration) values of 2.5, 0.9, 3.1 and 0.1 mgCIP L−1 for Ochrobactrum sp., Brevundimonas sp., Sphingomonas sp. and E. coli, respectively. Assessing the effect of antibiotics in the effluent on the microorganisms’ growth by a disk diffusion test, only E. coli culture showed inhibition at the concentration of 5.0 mgCIP L−1. The study emphasized the potential of AFBBR to reduce ecotoxicity in the sewage on aquatic biota.

Journal of environmental chemical engineering, Feb 1, 2021

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Bioprocess and Biosystems Engineering, 2021

Biomass samples from a structured-bed reactor subjected to recirculation and intermittent aeratio... more Biomass samples from a structured-bed reactor subjected to recirculation and intermittent aeration (SBRRIA) were analyzed to investigate the bacterial community shift along with the changes in the C/N ratio. The C/N ratios tested were 7.6 ± 1.0 (LNC) and 2.9 ± 0.4 (HNC). The massive sequencing analyses revealed that the microbial community adjusted itself to different organic and nitrogenous applied loads, with no harm to reactor performance regarding COD and Total-N removal. Under LNC, conventional nitrification and heterotrophic denitrification steered the process, as indicated by the detection of microorganisms affiliated with Nitrosomonadaceae, Nitrospiraceae, and Rhodocyclaceae families. However, under HNC, the C/N ratio strongly affected the microbial community, resulting in the prevalence of members of Saprospiraceae, Chitinophagaceae, Xanthomonadaceae, Comamonadaceae, Bacillaceae, and Planctomycetaceae. These families include bacteria capable of using organic matter derived from cell lysis, ammonia-oxidizers under low DO, heterotrophic nitrifiers–aerobic denitrifiers, and non-isolated strains of Anammox. The DO profile confirmed that the stratification in aerobic, anoxic, and anaerobic zones enabled the establishment of different nitrogen degradation pathways, including the Anammox.

Journal of Water Process Engineering, 2016