Phosphorus removal in wastewater treatment is commonly achieved by chemical precipitation, enhanced biological phosphorus removal (EBPR) or a simultaneous combination of the two. A defined anaerobic condition is widely regarded as the critical element to sustain EBPR. However, this study demonstrates that EBPR is indeed occurring in a 4.5 m3/h membrane bioreactor (MBR) pilot plant without a defined anaerobic condition. Although designed for chemical precipitation alone, a low average Fe/P molar ratio (iron dose/phosphorus removed) of 0.9 ± 0.1 suggests that EBPR could be contributing to a simultaneous phosphorus removal. Weekly flow-proportional grab samples through the process showed a phosphate (P) release between the primary anoxic tanks, followed by a larger uptake in the aerobic tanks. In laboratory batch tests with limited acetate supply in the presence of nitrates, the anoxic P-release began and then abruptly stopped whilst the nitrate concentration continued to decrease. This could be explained by denitrifiers out-competing PAOs for soluble substrate since a large P-release occurred when excess acetate was supplied in the presence of nitrates. It is therefore unlikely that PAOs are operating in the pilot despite the presence of nitrates as was concluded in a study with similar spontaneous EBPR observations. Instead, it is suggested that EBPR is enabled by intermittent anaerobic conditions in the primary anoxic tanks due to low nitrate concentrations (< 1 mg NO3/l) recirculating back after post-denitrification. The external carbon source supplied to the pilot was changed from glycerol to ethanol to assess any effect on the spontaneous EBPR. After ethanol had been supplied for 30 days, increased P-release rates were observed in batch tests supplied with ethanol (0.1 to 0.4 mg P/g VSS∙h) and batch tests supplied with acetate (8.6 ± 0.4 to 10.3 ± 0.4 mg P/g VSS∙h). However, the overall consumption of glycerol was less than that of ethanol, whilst the total phosphorus removal and the Fe/P ratio remained similar whether ethanol or glycerol was supplied to the pilot plant. Should operators wish to avoid any possible spontaneous P-release in the post-denitrification step, methanol is recommended as the external carbon source when considering laboratory P-release results, past research and operation costs. / Fosforrening av avloppsvatten uppnås vanligtvis genom kemisk utfällning, enhanced biological phosphorus removal (EBPR) eller en kombination av dessa två samtidig. Ett definierat anaeroba förhållanden betraktas allmänt som det kritiska elementet för att upprätthålla EBPR. Dock visar denna studie att EBPR verkligen förekommer i en pilotanläggning med membranbioreaktor (MBR) utan ett definierat anaeroba förhållanden. Veckovis flödesproportionella stickprover genom processen visade en ökad fosfat (P) halt mellan de primära anoxisk tankarna, följt av ett upptag i de aerobiska tankarna. Även om det är planerat för bara kemisk fosforrening, ett lågt medel Fe/P molförhållande (järndos/fosfor bortagning) på 0,9 ± 0,1 föreslår att EBPR kan bidra till ett samtidigt fosforrening. Laboratorie-P-utsläppningstest bekräftade EBPR-aktivitet med en hög medel P-utsläpp av 9,3 ± 0,9 mg P/g VSS∙h med acetat. Tillsammans indikerar dessa resultat att biologiskt fosforrening kompletterade den kemiska fosforrening under undersökningsperioden. P- utsläppningstest visade att närvaron av nitrater inte påverkade PAO-aktiviteter när acetat tillfördes i överskott. Med begränsad acetattillförsel förhindrade emellertid närvaron av nitrater någon initial P-utsläpp och inga efterföljande fermenteringsbiprodukter observerades. Slutsatsen dras att effektiv nitrifikation-denitrifikation och hög recirkulation resulterar i låga nitrathalt i primär anox tankar. Detta orsakar intermittenta anaerobisk förhållanden som, tillsammans med lämpliga substrathalt i inloppsvatten, möjliggör EBPR att ske. Den externa kolkällan som levererades till MBR-piloten ändrades från glycerol till etanol för att undersöka potentialen att öka EBPR-andelen av fosforrening. P-utsläpp i labbtester med etanol dosering ökade från 0,1 till 0,4 mg P/g VSS∙h och tester med acetat dosering ökade från 8,6 ± 0,4 till 10,3 ± 0,4 mg P/g VSS∙h när slam hade anpassats till etanol i 30 dagar. Vid pilotanläggningens drift konsumerades i alla fall mindre glycerol under dess användningsperiod än etanol, och Fe / P- förhållandet var likadant oavsett om glycerol eller etanol tillsatts. Olika andra kolkällor testades i parallella P-utsläppningstest. VFA producerat genom jäsning av matavfall och primärt slam i ett pågående projekt, och huvudsakligen bestående av kapronsyra, resulterade i den näst högsta P- utsläpp. P-utsläpp från alkoholer var märkbart lägre än VFA-baserade kolkällor. Det betyder att risken är låg för oväntat P-utsläpp i den slutliga biologiska zonen om en alkoholbaserad kollkällan doseras där. Minskad förluftning och en liten dos VFA-baserat substrat i den första biologiska zonen skulle bidra till en betydande EBPR som skulle möjliggöra en ytterligare reducerad basdos av järnsulfat.

The Upper Cretaceous Tropic Shale of southern Utah captures critical oceanographic changes that occurred during Oceanic Anoxic Event 2 (OAE 2) and the transgression of the Greenhorn Sea. We investigated the response of planktic and benthic foraminifera in a shallow (<100 >m) marine environment stressed by the onset of OAE 2 during the Cenomanian-Turonian boundary (CTB; 93.9 Ma) to determine the oceanographic mechanisms controlling the observed turnovers in the foraminiferal record. This study is based on high-resolution quantitative foraminifera counts and isotope paleoecology (d18O and d13C) from a 40-m outcrop. The OAE 2 interval is identified by a distinctive d13Corg signature and by correlation of bentonites and limestones across the seaway. Results of assemblage analyses indicate discrete intervals of environmental perturbations across the CTB interval. At the onset of OAE 2, surface waters were dominated by planktic Guembelitra cenomana with minor species of Heterohelix. Benthic abundances increase and were initially dominated by oxygen tolerant infaunal Neobulimina albertensis. Epifaunal Gavelinella dakotaensis briefly proliferated during the core of the OAE 2 and coinciding with the planktic “Heterohelix shift” and increasing accumulation of organic matter. The peak of OAE 2 at ~17 m is marked by a rapid shift to infaunal Neobulimina dominance. We suspect incursion of oxygen-poor Tethyan intermediate waters with peak transgression during the early Turonian, coupled with high productivity in surface waters resulted in the rapid depletion of benthic oxygen. The foraminiferal record reveals strong cyclicity in planktic/benthic ratio resembling parasequences that correlate to the GSSP in central Colorado.

The Toarcian Oceanic Anoxic Event (T-OAE; ~183 million years ago) represents an interval during the Mesozoic when the emplacement of the Karoo-Ferrar Large Igneous Province (LIP) is thought to have resulted in significant environmental change. Associated with this interval was the widespread deposition of organic-rich sediments, carbon cycle and seawater chemistry changes, global warming, the development of marine anoxia, and major extinction events. The majority of studies of this event that have documented these responses have come from the Boreal and Tethyan regions of Europe, thus casting some doubt to the regional versus global significance of the event. Thus my dissertation has sought to reconstruct biogeochemical and paleoenvironmental changes across the T-OAE from a sedimentary succession that was deposited on the margins of a different ocean basin away from the well-studied European successions. Specifically, I have studied the chemostratigraphy of the Fernie Formation of the Western Canada Sedimentary Basin (WCSB), which was deposited on the eastern margin of the Panthalassa Ocean. The Toarcian carbon isotope excursions (CIEs) in the WCSB confirm that these features are global phenomena. I have suggested a new driver for small-scale CIEs observed during the event: the release of wetland-derived methane during progressive global warming. The osmium isotope record and numerical modeling of the osmium cycle suggests that continental weathering rates increased during the T-OAE by 230 – 540%. Rhenium abundance data also suggests that the increased geographic extent of marine anoxia during the T-OAE caused a global drawdown in the seawater rhenium inventory. Iron speciation data are used to reconstruct redox conditions within the WCSB, which suggest ferruginous conditions developed in the more distal locations at the onset of the T-OAE before returning to euxinic (anoxic and sulfidic) conditions. This is likely related to enhanced pyrite burial on a global scale, which caused the drawdown of the seawater sulfate inventory, thus limiting pyrite formation in the distal locations. The proximal setting remained euxinic across the T-OAE, and in all locations the iron speciation data suggest anoxic conditions persistent well after the interval that has been traditionally called the end of the T-OAE. / Ph. D.

The treatability of a high strength industrial wastewater, 9,000 mg/L as chemical oxygen demand (COD), by three sequencing batch reactor (SBRs) systems operated under alternating redox environments: anaerobic/aerobic (ANA), anoxic/aerobic (ANX), and aerobic was investigated. A synthetic wastewater was modeled after a wastewater from an existing chemical processing facility. The largest component, hydroxypivaldehyde, was unavailable for the use in this research and was substituted by pivalic acid, both of which have a tertiary carbon. No significant degradation occurred in the anaerobic phase of operation; however, 55-65% of the COD was removed during anoxic operation. Simultaneous removal of pivalic acid and acetic acid was seen in both the anoxic and aerobic reaction phases. The anoxic/aerobic SBR provided the best overall treatability of the synthetic wastewater based on: effluent quality, sludge characteristics and settling properties. The results suggested that anoxic/aerobic treatment schemes are a viable treatment alternative for industrial wastewaters containing high concentrations of organic acids, including acids with tertiary carbons. The treatability of the three alternating redox environments on the Industry's wastewater was also investigated. Again, no significant degradation of the industrial wastewater occurred during the anaerobic reaction phase. During the anoxic reaction phase, 15-20% of the COD was removed from the industrial wastewater in contrast to the high removals seen with the synthetic wastewater. The aerobic SBR provided the best COD removal for the industrial wastewater. The performance differences between the synthetic and industrial wastewaters stress the importance of treatability studies on the actual industrial wastewater. Biological treatment of the synthetic and Industry wastewaters was unable to achieve the effluent goal of 100 mg/L as COD. Sand filtration followed by granular activated carbon adsorption treatment of the effluent from the synthetic wastewater-fed ANA SBR provided the COD removal necessary to achieve the effluent goal. / Master of Science

O Cretáceo inferior é caracterizado por mudanças drásticas em todos os envelopes terrestres, envolvendo desde variações geodinâmicas a importantes mudanças paleoclimáticas. Entretanto, há poucos registros desses eventos no hemisfério sul, sendo o DSDP-511 o principal deles. Com objetivo de gerar melhores vínculos temporais para os registros do Cretáceo Inferior no hemisfério sul, foram realizados estudos paleomagnéticos e de magnetismo ambiental em alta resolução espacial em uma secção do sítio DSDP-511 (núcleos 58 e 59), a qual corresponde ao intervalo entre 508,77 a 523,94 mbsf (meters below sea floor) e abrange os estágios Barremiano e Aptiano. A compreensão dos eventos paleoclimáticos neste sítio não é trivial, uma vez que, além de ambiguidade nas idades inferidas pela bioestratigrafia, apenas parte do evento de anoxia oceânica OAE 1a está registrada devido a uma lacuna de amostragem. Foram identificados dois principais portadores magnéticos através da análise de curvas de aquisição e desmagnetização de magnetização remanente anisterética (ARM) e magnetização remanente isotérmica (IRM). O mineral de baixa corecividade é a magnetita, confirmada a partir da desmagnetização de IRM triaxial. Sua origem é provavelmente detrítica. O portador de alta coercividade foi interpretado como hematita. A contribuição relativa dos portadores magnéticos apresentou uma variação acentuada no intervalo entre 512 e 514 mbsf, sendo manifestada através de um pico em todos os parâmetros de magnetismo ambiental. Esta variação está associada também à maior concentração de minerais magnéticos neste intervalo e coincide com um marcado aumento na temperatura da superfície dos oceanos. Após desmagnetização progressiva e identificação da componente magnética característica foram definidas duas zonas de polaridade normal e uma zona de polaridade reversa (518,9 e 518,16 mbsf). Além disso, foi definida uma zona discreta de polaridade reversa em 509,20 mbsf. Os resultados encontrados apresentam diferenças significativas quando comparadas com estudos anteriores no mesmo testemunho. Uma datação Re-Os em folhelhos negros de 125,3 ± 2,2 Ma entre 519,01 e 519,40 mbsf foi obtida recentemente e forneceu um vínculo absoluto de idade para o intervalo estudado. O padrão de reversões encontrado foi compatível com a presença dos chrons M0r e ISEA. O modelo de idades proposto permite reposicionar o evento OAE 1a entre as profundidades 513,5 a 518 mbsf, incluindo a parte não recuperada do testemunho. Esta interpretação também compatível com dados de TOC e de 13C obtidos recentemente por outros autores. / The lower Cretaceous is characterized by drastic changes in the Earth, from geodynamic variations to important paleoclimatic changes. However, there are few records of these events in the southern hemisphere, the DSDP-511 being the most comprehensive one. In order to provide better temporal constraints for the lower Cretaceous records in the southern hemisphere, paleomagnetic and high-resolution environmental magnetism studies were performed in a section of the DSDP-511 site (cores 58 and 59), which corresponds to the interval between 508.77 to 523.94 mbsf (meters below sea floor) and covers the Barremian and Aptian stages. The correct assessment of paleoclimatic events at this site is not trivial because, in addition to the ambiguity at the ages inferred by biostratigraphy, only part of the OAE 1a (oceanic anoxic event) was recovered. Two main magnetic carriers were identified through the analysis of acquisition and demagnetization of anhysteretic remanent magnetization (ARM) and isothermal remanent magnetization (IRM) curves. The low coercivity mineral is magnetite, as attested by triaxial IRM demagnetization. Its origin is likely detrital. The high coercivity carrier was interpreted as hematite. The relative contribution of magnetic carriers has a strong variation in the interval between 512 and 514 mbsf, being manifested by a peak in all parameters of environmental magnetism. This variation is also associated with the higher concentration of magnetic minerals and coincides with a marked increase in the sea surface temperature in this interval. After stepwise demagnetization and identification of the characteristic magnetic component, two zones of normal polarity and a zone of reverse polarity (518.9 and 518.16 mbsf) were defined. In addition, a discrete zone of reverse polarity was defined at 509.20 mbsf. The results obtained present significant differences when compared with previous studies in the same core. A Re-Os dating on black shales of 125.3 ± 2.2 Ma between 519.01 and 519.40 mbsf was obtained recently and provided an absolute constraint onto which the polarity zones could be matched. The pattern of reversions found is compatible with the presence of chrons M0r and ISEA. The proposed age model allows repositioning the OAE 1a event between depths 513.5 to 518 mbsf in the core and overlap the unrecovered part. This interpretation is also compatible with TOC and 13C data recently obtained by other authors.

O Cretáceo inferior é caracterizado por mudanças drásticas em todos os envelopes terrestres, envolvendo desde variações geodinâmicas a importantes mudanças paleoclimáticas. Entretanto, há poucos registros desses eventos no hemisfério sul, sendo o DSDP-511 o principal deles. Com objetivo de gerar melhores vínculos temporais para os registros do Cretáceo Inferior no hemisfério sul, foram realizados estudos paleomagnéticos e de magnetismo ambiental em alta resolução espacial em uma secção do sítio DSDP-511 (núcleos 58 e 59), a qual corresponde ao intervalo entre 508,77 a 523,94 mbsf (meters below sea floor) e abrange os estágios Barremiano e Aptiano. A compreensão dos eventos paleoclimáticos neste sítio não é trivial, uma vez que, além de ambiguidade nas idades inferidas pela bioestratigrafia, apenas parte do evento de anoxia oceânica OAE 1a está registrada devido a uma lacuna de amostragem. Foram identificados dois principais portadores magnéticos através da análise de curvas de aquisição e desmagnetização de magnetização remanente anisterética (ARM) e magnetização remanente isotérmica (IRM). O mineral de baixa corecividade é a magnetita, confirmada a partir da desmagnetização de IRM triaxial. Sua origem é provavelmente detrítica. O portador de alta coercividade foi interpretado como hematita. A contribuição relativa dos portadores magnéticos apresentou uma variação acentuada no intervalo entre 512 e 514 mbsf, sendo manifestada através de um pico em todos os parâmetros de magnetismo ambiental. Esta variação está associada também à maior concentração de minerais magnéticos neste intervalo e coincide com um marcado aumento na temperatura da superfície dos oceanos. Após desmagnetização progressiva e identificação da componente magnética característica foram definidas duas zonas de polaridade normal e uma zona de polaridade reversa (518,9 e 518,16 mbsf). Além disso, foi definida uma zona discreta de polaridade reversa em 509,20 mbsf. Os resultados encontrados apresentam diferenças significativas quando comparadas com estudos anteriores no mesmo testemunho. Uma datação Re-Os em folhelhos negros de 125,3 ± 2,2 Ma entre 519,01 e 519,40 mbsf foi obtida recentemente e forneceu um vínculo absoluto de idade para o intervalo estudado. O padrão de reversões encontrado foi compatível com a presença dos chrons M0r e ISEA. O modelo de idades proposto permite reposicionar o evento OAE 1a entre as profundidades 513,5 a 518 mbsf, incluindo a parte não recuperada do testemunho. Esta interpretação também compatível com dados de TOC e de 13C obtidos recentemente por outros autores. / The lower Cretaceous is characterized by drastic changes in the Earth, from geodynamic variations to important paleoclimatic changes. However, there are few records of these events in the southern hemisphere, the DSDP-511 being the most comprehensive one. In order to provide better temporal constraints for the lower Cretaceous records in the southern hemisphere, paleomagnetic and high-resolution environmental magnetism studies were performed in a section of the DSDP-511 site (cores 58 and 59), which corresponds to the interval between 508.77 to 523.94 mbsf (meters below sea floor) and covers the Barremian and Aptian stages. The correct assessment of paleoclimatic events at this site is not trivial because, in addition to the ambiguity at the ages inferred by biostratigraphy, only part of the OAE 1a (oceanic anoxic event) was recovered. Two main magnetic carriers were identified through the analysis of acquisition and demagnetization of anhysteretic remanent magnetization (ARM) and isothermal remanent magnetization (IRM) curves. The low coercivity mineral is magnetite, as attested by triaxial IRM demagnetization. Its origin is likely detrital. The high coercivity carrier was interpreted as hematite. The relative contribution of magnetic carriers has a strong variation in the interval between 512 and 514 mbsf, being manifested by a peak in all parameters of environmental magnetism. This variation is also associated with the higher concentration of magnetic minerals and coincides with a marked increase in the sea surface temperature in this interval. After stepwise demagnetization and identification of the characteristic magnetic component, two zones of normal polarity and a zone of reverse polarity (518.9 and 518.16 mbsf) were defined. In addition, a discrete zone of reverse polarity was defined at 509.20 mbsf. The results obtained present significant differences when compared with previous studies in the same core. A Re-Os dating on black shales of 125.3 ± 2.2 Ma between 519.01 and 519.40 mbsf was obtained recently and provided an absolute constraint onto which the polarity zones could be matched. The pattern of reversions found is compatible with the presence of chrons M0r and ISEA. The proposed age model allows repositioning the OAE 1a event between depths 513.5 to 518 mbsf in the core and overlap the unrecovered part. This interpretation is also compatible with TOC and 13C data recently obtained by other authors.

Two oceanographic cruises were conducted during September 2003 and March 2004 in the eastern half of the Cariaco Basin. Specific objectives were to examine the hydrography of the seasonal upwelling plume characteristic of this region, the spatial distribution of particles in the area, and to help determine the source and relative importance of in situ particle production vs. terrigenous particles delivered laterally from the coast. During September 2003, average surface salinities within the basin were higher (36.6) relative to Caribbean Sea waters outside the basin (35.6). Salinity patterns indicated that the Orinoco and Amazon River plumes did not enter or influenced the basin directly. The upwelling plume in March 2004 stimulated primary productivity. Beam attenuation and CDOM fluorescence profiles showed marked vertical structure in biomass of microbial populations, particularly near the oxic-anoxic interface typically located between about 250 and 300 m. There is an increasing difference in temperature and salinity between the Cariaco Basin and the adjacent Caribbean Sea below 200 m. Inside the Basin temperatures and salinities were higher by 4oC and 0.5. The influence of local rivers on the Cariaco Basin was evident during September 2003. Low salinity plumes with high beam attenuation (1m-1) lined the southern margin of the Basin. The primary rivers that affected the basin were the Unare and Neverí Their sediment input affected the shelf near the river mouths, and a surrounding radius of up to 40 Km. Their low salinity plumes were carried northwestward toward the CARIACO time series station. In March 2004, there was minimal or no terrigenous input from local rivers. Near the Manzanares River, off the city of Cumaná and near Cubagua Island, located south of Margarita Island, attenuation due to suspended particles (0.09 m-1) was observed at depth (70-150 m) during both cruises (0.09-0.15 m-1). Therefore, sediment transport from the shelf into the basin seems to occur year-round. More observations are necessary to determine the nature and origin of these particles. In March 2004, there was minimal or no terrigenous input

Phytosterols are steroid chemicals produced by plants for the purposes of membrane function and hormone production. Phytosterols can cause endocrine disruption in aquatic species at very low concentrations and are suspected of contributing to endocrine disruption linked to pulp and paper effluent. Wastewater from the pulp and paper industry is often treated biologically in aerated stabilization basins (ASBs) that expose phytosterols to a range of redox zones. Phytosterol removal in ASBs varies and stigmasterol has even been shown to increase across the treatment system. Little is known about the microbial processes that occur within ASBs and their effect on phytosterol removal. The objective of this research was to assess the biotransformation potential of phytosterols in a simulated ASB treatment system and to improve understanding of the processes that occur within the various redox zones and their impact on the removal of phytosterols. To assess the biotransformation of phytosterols under aerobic conditions, three assays were conducted using a stock aerobic culture fed with pulp and paper wastewater. The assays tested three conditions: phytosterols present as a sole added carbon source, phytosterols with dextrin as an added carbon source, and phytosterols with ethanol as a solubilizing agent and added carbon source. Phytosterol biotransformation was found to be limited by low phytosterol solubility. When solubilized, phytosterol removal occurred in two phases: an initial near-linear removal, followed by accelerated removal during the culture's stationary stage, possibly due to the release of extracellular cholesterol oxidase. The anoxic and anaerobic biotransformation of phytosterols was examined through a series of three semi-batch cultures maintained under nitrate-reducing, sulfate-reducing and fermentative/methanogenic conditions, all developed from stock cultures fed with pulp and paper wastewater. Phytosterol removal was significant in the nitrate-reducing culture, although microbial activity and phytosterol removal declined in later stages. Phytosterol removal was also observed in the sulfate-reducing culture, although there was a significant lag period before removal occurred. No phytosterol removal was observed in the fermentative/methanogenic culture. Phytosterol biotransformation was also examined in the context of a lab-scale ASB fed continuously with pulp and paper wastewater. The steady-state ASB effluent and sediment characteristics were examined over three hydraulic retention times (HRTs). Effluent quality was not significantly affected by a change in HRT but sediment characteristics were significantly affected and, at shorter HRTs, phytosterols accumulated in the sediment. Wastewater bioassays demonstrated the release of phytosterols during the breakdown of solids. This research improves the understanding of biological processes within ASBs and their effect on phytosterol removal.

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-07-01T15:18:35Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação de Mestrado Versão Final Completa - Gabriela Valones Rodrigues de Araújo.pdf: 2764512 bytes, checksum: 6abd4e4eb59a8eaec35b37f1ac434ba8 (MD5) / Made available in DSpace on 2016-07-01T15:18:35Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação de Mestrado Versão Final Completa - Gabriela Valones Rodrigues de Araújo.pdf: 2764512 bytes, checksum: 6abd4e4eb59a8eaec35b37f1ac434ba8 (MD5) Previous issue date: 2015-08-28 / CNPq / A remoção de carbono e nitrogênio foi avaliada através de um sistema inovador de reatores anaeróbio, aeróbio e anóxico em série de fluxo contínuo. Foram testadas diferentes condições operacionais quanto ao Tempo de Detenção Hidráulica (TDH) por reator (anaeróbio, aeróbio e anóxico) na Fase 1, Fase 2, Fase 3 e Fase 4 que foi de 7h, 10h, 10h e 5h, respectivamente; e Oxigênio Dissolvido (OD) nas concentrações de 0,5-1,2 mg O2.L-1, 0,5-1,5 mg O2.L-1, 1,1-2,1 mg O2.L-1 e 1,1-2,5 mg O2.L-1 no reator aeróbio, nas respectivas fases. O reator anaeróbio promoveu uma excelente remoção de matéria orgânica (85%), bem como, atuou como pré-tratamento na redução da competição entre os micro-organismos heterotróficos e nitrificantes autotróficos no reator aeróbio. A maior eficiência da nitrificação foi obtida quando a concentração de OD foi mantida entre 1,1 e 2,5 mg L-1. No entanto, foi observada uma diminuição na eficiência da desnitrificação, que pode estar relacionada com uma diminuição da razão DQO / NTK. A eficiência alcançada pelo sistema para DQO (bruta/filtrada) e NTK foi de 88 e 52%, respectivamente. O sistema foi operado sem adição de fonte externa de carbono no reator anóxico. As análises de Biologia Molecular constataram a presença de Bactérias Oxidantes do Nitrito (Nitrospira), Bactérias Oxidantes de Amônia, Bactérias Desnitrifcantes e Anammox. / Removal of carbon and nitrogen was assessed through an innovative system of anaerobic , aerobic and anoxic reactors streaming series. Different operating conditions were tested for hydraulic retention time (HRT ) per reactor (anaerobic, aerobic and anoxic) in Phase 1 , Phase 2 , Phase 3 and Phase 4 which was 7h , 10h , 10h and 5h , respectively; and Dissolved Oxygen (DO) concentrations of 0.5-1.2 mg O2.L-1, 0.5-1.5 mg O2.L-1, 1.1-2.1 mg O2.L-1 and 1.1-2.5 mg O2.L-1, were tested. The anaerobic promoted an excellent removal of organic matter (85% ) and served as pretreatment to reduce the competition between heterotrophic and autotrophic nitrifying microorganisms in the aerobic reactor. The highest efficiency of nitrification was obtained when the concentration of DO was maintained between 1.1-2.5 mg O2.L-1. However, it was observed a decrease in the efficiency of denitrification, which can be related to a decrease in the ratio COD / TKN. The efficiency achieved by the system for COD and TKN was 88 and 52%, respectively. The system was operated without addition of external carbon source in the anoxic reactor. The molecular biology analysis found the presence of Oxidizers Nitrite Bacteria (Nitrospira), Oxidizers Ammonia Bacteria, Desnitrifcantes Bacteria and Anammox.

BTX biodegradation rates, biochemical expression patterns and microbial ecology were studied under anoxic (denitrifying), anoxic/microaerobic/aerobic, and anoxic/microaerobic conditions in activated sludge sequencing batch reactors. The studies showed that toluene and m-xylene were denitrified via benzoyl-CoA reductase. Although benzene, o-, and p-xylene were recalcitrant under denitrifying conditions, they were biodegraded under microaerobic (< 0.2 mg/L dissolved oxygen) and nitrate or nitrite (NOx)-supplemented microaerobic conditions. The patterns of the specific enzymes associated with BTX biodegradation under microaerobic conditions indicated that the three compounds were metabolized by oxygen-dependent pathways. The expression levels of catechol 1, 2-dioxygenase and catechol 2, 3-dioxygenase under microaerobic conditions were induced to levels as high as under aerobic conditions (> 4 mg/L dissolved oxygen). Benzene, o-, and p-xylene biodegradation rates were twice as fast under NO_x-supplemented compared to NO_x-free microaerobic conditions, and the specific biodegradation rates under aerobic and NO_x-supplemented microaerobic conditions were comparable. 16S rRNA probes targeting representative toluene-degraders were used to investigate the microbial communities in the three sequencing batch reactors by using a dot blot hybridization technique. The hybridization results suggest that multiple redox environments fostered a more diverse microbial community and the activities of the target organisms in the reactors with multiple redox environments were higher than in the single redox reactor. Additionally, facultative toluene-degraders appeared to play a less significant role than the strict anoxic and aerobic toluene-degraders in all three SBRs. / Ph. D.