Quaternary paleoenvironments and relative sea-level changes in Marajo Island (Northern Brazil): Facies, delta(13)C, delta(15)N and C/N

The reconstruction of physical environments of Amazonian areas is of great interest to determine the dynamic evolution of the Amazon drainage basin. However. few studies have emphasized the Quaternary deposits in this region. which is mostly due to the lack of natural exposures imposed by the low topography. This work integrates facies analysis. radiocarbon dating, delta(13)C, delta(15)N, and C/N of an 124 m-thick core from an area located at the mouth of the Amazon River. northeastern Amazonia. The study records deposits up to 50.795 (14)C yr B P. in age. which formed in a variety of depositional environments including fluvial channel, tidal flat, outer estuarine basin to shallow marine. inner estuarine basin, estuarine channel and lagoon. Facies interpretation was significantly improved with the inclusion of delta(13)C, delta(15)N, and C/N analyses of organic matter extracted from the sediments The obtained values conform to a transitional. mostly estuarine paleosetting evolved during successive relative sea-level fluctuations. The results suggest fluvial deposition between 40,950 (+/- 590) and 50.795 (14)C yr B P, with a rise in relative sea level that commenced between 35,567 (+/- 649) and 39,079 (+/- 1114) (14)C yr B P. An overall transgression took place until 29,340 (+/- 340) (14)C yr B P., after which the relative sea level dropped, favoring valley rejuvenation and incision. Following this time up to 10,479 (+/- 34) (14)C yr B.P. a rise in relative sea level filled up the valley with estuarine deposits After 10.479(+/- 34) (14)C yr B.P., the estuary was replaced by a lagoon At the end of the Holocene, the coastline prograided approximately 45 km northward, replaci ng the lagoon by a lake system Despite the influence of eustatic fluctuations. regional tectonics played a significant role to create new space where these Late Pleistocene and Holocene sediments accumulated. (C) 2009 Elsevier B V All rights reserved.

AnSBBR Applied to a Personal Care Industry Wastewater Treatment: Effects of Fill Time, Volume Treated Per Cycle, and Organic Load

A study was performed regarding the effect of the relation between fill time, volume treated per cycle, and influent concentration at different applied organic loadings on the stability and efficiency of an anaerobic sequencing batch reactor containing immobilized biomass on polyurethane foam with recirculation of the liquid phase (AnSBBR) applied to the treatment of wastewater from a personal care industry. Total cycle length of the reactor was 8 h (480 min). Fill times were 10 min in the batch operation, 4 h in the fed-batch operation, and a 10-min batch followed by a 4-h fed batch in the mixed operation. Settling time was not necessary since the biomass was immobilized and decant time was 10 min. Volume of liquid medium in the reactor was 2.5 L, whereas volume treated per cycle ranged from 0.88 to 2.5 L in accordance with fill time. Influent concentration varied from 300 to 1,425 mg COD/L, resulting in an applied volumetric organic load of 0.9 and 1.5 g COD/L.d. Recirculation flow rate was 20 L/h, and the reactor was maintained at 30 A degrees C. Values of organic matter removal efficiency of filtered effluent samples were below 71% in the batch operations and above 74% in the operations of fed batch followed by batch. Feeding wastewater during part of the operational cycle was beneficial to the system, as it resulted in indirect control over the conversion of substrate into intermediates that would negatively interfere with the biochemical reactions regarding the degradation of organic matter. As a result, the average substrate consumption increased, leading to higher organic removal efficiencies in the fed-batch operations.

AnSBBR Applied to the Treatment of Metalworking Fluid Wastewater: Effect of Organic and Shock Load

An investigation was performed regarding the application of a mechanically stirred anaerobic sequencing batch biofilm reactor containing immobilized biomass on inert polyurethane foam (AnSBBR) to the treatment of soluble metalworking fluids to remove organic matter and produce methane. The effect of increasing organic matter and reactor fill time, as well as shock load, on reactor stability and efficiency have been analyzed. The 5-L AnSBBR was operated at 30 A degrees C in 8-h cycles, agitation of 400 rpm, and treated 2.0 L effluent per cycle. Organic matter was increased by increasing the influent concentration (500, 1,000, 2,000, and 3,000 mg chemical oxygen demand (COD)/L). Fill times investigated were in the batch mode (fill time 10 min) and fed-batch followed by batch (fill time 4 h). In the batch mode, organic matter removal efficiencies were 87%, 86%, and 80% for influent concentrations of 500, 1,000, and 2,000 mgCOD/L (1.50, 3.12, and 6.08 gCOD/L.d), respectively. At 3,000 mgCOD/L (9.38 gCOD/L.d), operational stability could not be achieved. The reactor managed to maintain stability when a shock load twice as high the feed concentration was applied, evidencing the robustness of the reactor to potential concentration variations in the wastewater being treated. Increasing the fill time to 4 h did not improve removal efficiency, which was 72% for 2,000 mgCOD/L. Thus, gradual feeding did not improve organic matter removal. The concentration of methane formed at 6.08 gCOD/L was 5.20 mmolCH(4), which corresponded to 78% of the biogas composition. The behavior of the reactor during batch and fed-batch feeding could be explained by a kinetic model that considers organic matter consumption, production, and consumption of total volatile acids and methane production.

Influence of feed time and sulfate load on the organic and sulfate removal in an ASBR

The removal of sulfate and organic matter was assessed in an ASBR, which treated wastewater containing 500 mg COD L(-1) (3 g COD L(-1) d(-1)) in 8 h-cycles at 30 degrees C. The wastewater was enriched with sulfate at [COD/SO(4)(2-]) ratios of 1.34, 0.67 and 0.34 (8.8,4.5 and 2.2 gSO(4)(2-) L(-1) d(-1)). For each COD/[SO(4)(2-)] ratio fill times used were: 10 min (batch), 3 and 6 h (fed-batch), achieving sulfate reduction of 30%, 72% and 72% (COD/[SO(4)(2-)] of 1.34); 25%, 58% and 55% (COD/[SO(4)(2-)] of 0.67) and 23%, 37% and 27% (COD/[SO(4)(2-)] of 0.34), respectively, and organic matter removal of 87%, 68% and 80% (COD/[SO(4)(2-)] of 1.34); 78%, 75% and 69% (COD/[SO(4)(2-)] of 0.67) and 85%, 84% and 83% (COD/[SO(4)(2-)] of 0.34), respectively. The results showed that fed-batch operation improved sulfate reduction, whereas organic matter removals were similar for batch and fed-batch operation. In addition, increase in sulfate loading in the fed-batch operation improved organic matter removal. (C) 2010 Elsevier Ltd. All rights reserved.

Effect of Organic Load on the Performance and Methane Production of an AnSBBR Treating Effluent from Biodiesel Production

Currently, there is an increasing demand for the production of biodiesel and, consequently, there will be an increasing need to treat wastewaters resulting from the production process of this biofuel. The main objective of this work was, therefore, to investigate the effect of applied volumetric organic load (AVOL) on the efficiency, stability, and methane production of an anaerobic sequencing batch biofilm reactor applied to the treatment of effluent from biodiesel production. As inert support, polyurethane foam cubes were used in the reactor and mixing was accomplished by recirculating the liquid phase. Increase in AVOL resulted in a drop in organic matter removal efficiency and increase in total volatile acids in the effluent. AVOLs of 1.5, 3.0, 4.5 and 6.0 g COD L(-1) day(-1) resulted in removal efficiencies of 92%, 81%, 67%, and 50%, for effluent filtered samples, and 91%, 80%, 63%, and 47%, for non-filtered samples, respectively, whereas total volatile acids concentrations in the effluent amounted to 42, 145, 386 and 729 mg HAc L(-1), respectively. Moreover, on increasing AVOL from 1.5 to 4.5 g COD L(-1) day(-1) methane production increased from 29.5 to 55.5 N mL CH(4) g COD(-1). However, this production dropped to 36.0 N mL CH(4) g COD(-1) when AVOL was increased to 6.0 g COD L(-1) day(-1), likely due to the higher concentration of volatile acids in the reactor. Despite the higher concentration of volatile acids at the highest AVOL, alkalinity supplementation to the influent, in the form of sodium bicarbonate, at a ratio of 0.5-1.3 g NaHCO(3) g COD (fed) (-1) , was sufficient to maintain the pH near neutral and guarantee process stability during reactor operation.

Effect of specific feed volume on the performance of an anaerobic sequencing batch biofilm reactor (AnSBBR) with circulation treating different wastewaters under different organic loads

The objective of this research was to study the behavior of two anaerobic sequencing batch reactors, containing immobilized biomass (AnSBBR), as a function of the ratio of the volume of treated medium in each cycle to the total volume of reaction medium. The reactors, in which mixing was accomplished by recirculation of the liquid phase, were maintained at 30 +/- 1 degrees C and treated different wastewaters in 8-h cycles. The operational conditions imposed had the objective to investigate whether maintenance of a residual volume in the reactor would affect, at the end of each cycle, process efficiency and stability, as well as to verify the intensity of the effect for different types of wastewaters and organic loading rates. The first reactor, with work volume of 2.5 L, treated reconstituted cheese whey at an organic loading rate of 12 g COD.L(-1).d(-1) and presented similar effluent quality for the four conditions under which it was operated: renewal of 100, 70, 50 and 25 % of its work volume at each cycle. Despite the fact that reduction in the renewed volume did not significantly affect effluent quality, in quantitative terms, this reduction resulted in an increase in the amount of organic matter removed by the first reactor. The second reactor, with work volume of 1.8 L, treated synthetic wastewater at organic loading rates of 3 and 5 g COD.L(-1).d(-1) and operated under two conditions for each loading: renewal of 100 and 50 % of its work volume. At the organic loading rate of 3 g COD.L(-1).d(-1), the results showed that both effluent quality and amount of organic matter removed by the second reactor were independent of the treated volume per cycle. At the organic loading rate of 5 g COD.L(-1).d(-1), although the reduction in the renewed volume did not affect the amount of organic matter removed by the reactor, effluent quality improved during reactor operation with total discharge of its volume. In general, results showed process stability under all conditions, evidencing reactor flexibility and the potential to apply this technology in the treatment of different types of wastewater.

Effects of Feed Time, Organic Loading and Shock Loads in Anaerobic Whey Treatment by an AnSBBR with Circulation

The aim of this work was to investigate the effect of different feeding times (2, 4, and 6 h) and organic loading rates (3, 6 and 12 gCOD l(-1) day(-1)) on the performance of an anaerobic sequencing batch reactor containing immobilized biomass, as well as to verify the minimum amount of alkalinity that can be added to the influent. The reactor, in which mixing was achieved by recirculation of the liquid phase, was maintained at 30 +/- 1A degrees C, possessed 2.5 l reactional volume and treated 1.5 l cheese whey in 8-h cycles. Results showed that the effect of feeding time on reactor performance was more pronounced at higher values of organic loading rates (OLR). During operation at an OLR of 3 gCOD l(-1) day(-1), change in feeding time did not affect efficiency of organic matter removal from the reactor. At an OLR of 6 gCOD l(-1) day(-1), reactor efficiency improved in relation to the lower loading rate and tended to drop at longer feeding times. At an OLR of 12 gCOD l(-1) day(-1) the reactor showed to depend more on feeding time; higher feeding times resulted in a decrease in reactor efficiency. Under all conditions shock loads of 24 gCOD l(-1) day(-1) caused an increase in acids concentration in the effluent. However, despite this increase, the reactor regained stability readily and alkalinity supplied to the influent showed to be sufficient to maintain pH close to neutral during operation. Regardless of applied OLR, operation with feeding time of 2 h was which provided improved stability and rendered the process less susceptible to shock loads.

Effects of temperature at different organic loading levels on the performance of a fluidized-bed anaerobic sequencing batch bioreactor

An investigation was performed on the effect of temperature and organic load on the stability and efficiency of a 1.8-L fluidized-bed anaerobic sequencing batch reactor (ASBR), containing granulated biomass. Assays were carried out employing superficial up How velocity of 7 m/h, total cycle length of 6 h and synthetic wastewater volume of 1.3 L per cycle. The fluidized-bed ASH was operated at 15, 20, 25 and 30 degrees C with influent organic matter concentrations of 500 and 1000 mgCOD/L The system showed stability under all conditions and presented filtered samples removal efficiency ranging from 79 to 86%. A first-order kinetic model could be fitted to the experimental values of the organic matter concentration profiles. The specific kinetic parameter values of this model ranged from 0.0435 to 0.2360 L/(gTVS h) at the implemented operation conditions. in addition, from the slope of an Arrhenius plot, the activation energy values were calculated to be 16,729 and 12,673 cal/mol for operation with 500 and 1000 mgCOD/L, respectively. These results show that treatment of synthetic wastewater. with concentration of 500 mgCOD/L, was more sensitive to temperature variations than treatment of the same residue with concentration of 1000 mgCOD/L. Comparing the activation energy value for operation at 500 mgCOD/L with the value obtained by Agibert et al. (S.A. Agibert, M.B. Moreira, S.M. Ratusznei, J.A.D. Rodrigues, M. Zaiat, E. Foresti. Influence of temperature on performance of an ASBBR with circulation applied to treatment of low-strength wastewater. journal of Applied Biochemistry and Biotechnology, 136 (2007) 193-206) in an ASBBR treating the same wastewater at the same concentration, the value obtained in the fluidized-bed ASBR showed to be superior, indicating that treatment of synthetic wastewater in a reactor containing granulated biomass was more sensitive to temperature variations than the treatment using immobilized biomass. (c) 2008 Elsevier B.V. All rights reserved.

Influence of organic shock loads in an ASBBR treating synthetic wastewater with different concentration levels

Safe application of the anaerobic sequencing biofilm batch reactor (ASBBR) still depends on deeper insight into its behavior when faced with common operational problems in wastewater treatments such as tolerance to abrupt variations in influent concentration, so called shock loads. To this end the current work shows the effect of organic shock loads on the performance of an ASBBR, with a useful volume of 5 L, containing 0.5-cm polyurethane cubes and operating at 30 degrees C with mechanical stirring of 500 rpm. In the assays 2 L of two types of synthetic wastewater were treated in 8-h cycles. Synthetic wastewater I was based on sucrose-amide-cellulose with concentration of 500 mg COD/L and synthetic wastewater II was based on volatile acids with concentration ranging from 500 to 2000 mg COD/L. Organic shock loads of 2-4 times the operation concentration were applied during one and two cycles. System efficiency was monitored before and after application of the perturbation. When operating with concentrations from 500 to 1000 mg COD/L and shock loads of 2-4 times the influent concentration during one or two cycles the system was able to regain stability after one cycle and the values of organic matter, total and intermediate volatile acids, bicarbonate alkalinity and pH were similar to those prior to the perturbations. At a concentration of 2000 mg COD/L the reactor appeared to be robust, regaining removal efficiencies similar to those prior to perturbation at shock loads twice the operation concentration lasting one cycle and stability was recovered after two cycles. However, for shock loads twice the operation concentration during two cycles and shock loads four times the operation concentration during one or two cycles filtered sample removal efficiency decreased to levels different from those prior to perturbation, on an average of 90-80%, approximately, yet the system managed to attain stability within two cycles after shock application. Therefore, this investigation envisions the potential of full scale application of this type of bioreactor which showed robustness to organic shock loads, despite discontinuous operation and the short times available for treating total wastewater volume. (c) 2007 Elsevier Ltd. All rights reserved.

Application of an anaerobic packed-bed bioreactor for the production of hydrogen and organic acids

This study investigates the feasibility of an anaerobic bioreactor for treating low contents of organic matter to generate organic acids and hydrogen. The device employed for this purpose was a horizontal packed-bed bioreactor fed with glucose-based synthetic wastewater and operated with hydraulic retention times from 0.5 to 2 h. A microbial biofilm was developed without previous inoculation, using expanded clay beads (4.8-6.3 mm) as support material. Alkalinity was found to be the main parameter affecting the production of hydrogen and organic acids, and the system produced optimal output when operating without a buffer agent. The average hydrogen production was 2.48, 2.15 and 1.81 molH(2) mol(-1) of glucose for NaHCO3 influent concentrations of 0, 1000 and 2000 mg L-1, respectively. The operational regime of the bioreactor, the support material and the controlled alkalinity were effective in selecting and immobilizing microbial fermenting biofilms, which successfully produced hydrogen and organic acids throughout the operating period. Exploratory assays indicated the feasibility of organic acid extraction using an anionic polymeric resin. (C) 2007 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.

Modeling soil organic carbon dynamics in Oxisols of Ibiruba (Brazil) with the Century Model

introduction of conservation practices in degraded agricultural land will generally recuperate soil quality, especially by increasing soil organic matter. This aspect of soil organic C (SOC) dynamics under distinct cropping and management systems can be conveniently analyzed with ecosystem models such as the Century Model. In this study, Century was used to simulate SOC stocks in farm fields of the Ibiruba region of north central Rio Grande do Sul state in Southern Brazil. The region, where soils are predominantly Oxisols, was originally covered with subtropical woodlands and grasslands. SOC dynamics was simulated with a general scenario developed with historical data on soil management and cropping systems beginning with the onset of agriculture in 1900. From 1993 to 2050, two contrasting scenarios based on no-tillage soil management were established: the status quo scenario, with crops and agricultural inputs as currently practiced in the region and the high biomass scenario with increased frequency of corn in the cropping system, resulting in about 80% higher biomass addition to soils. Century simulations were in close agreement with SOC stocks measured in 2005 in the Oxisols with finer texture surface horizon originally under woodlands. However, simulations in the Oxisols with loamy surface horizon under woodlands and in the grassland soils were not as accurate. SOC stock decreased from 44% to 50% in fields originally under woodland and from 20% to 27% in fields under grasslands with the introduction of intensive annual grain crops with intensive tillage and harrowing operations. The adoption of conservation practices in the 1980s led to a stabilization of SOC stocks followed by a partial recovery of native stocks. Simulations to 2050 indicate that maintaining status quo would allow SOC stocks to recover from 81% to 86% of the native stocks under woodland and from 80% to 91 % of the native stocks under grasslands. Adoption of a high biomass scenario would result in stocks from 75% to 95% of the original stocks under woodlands and from 89% to 102% in the grasslands by 2050. These simulations outcomes underline the importance of cropping system yielding higher biomass to further increase SOC content in these Oxisols. This application of the Century Model could reproduce general trends of SOC loss and recovery in the Oxisols of the Ibiruba region. Additional calibration and validation should be conducted before extensive usage of Century as a support tool for soil carbon sequestration projects in this and other regions can be recommended. (C) 2009 Elsevier B.V. All rights reserved.

Spatial patterns of soil attributes and components in a mangrove system in Southeast Brazil (Sao Paulo)

Purpose Among environmental factors governing innumerous processes that are active in estuarine environments, those of edaphic character have received special attention in recent studies. With the objectives of determining the spatial patterns of soil attributes and components across different mangrove forest landscapes and obtaining additional information on the cause-effect relationships between these variables and position within the estuary, we analyzed several soil attributes in 31 mangrove soil profiles from the state of So Paulo (Guaruja, Brazil). Materials and methods Soil samples were collected at low tide along two transects within the CrumahA(0) mangrove forest. Samples were analyzed to determine pH, Eh, salinity, and the percentages of sand, silt, clay, total organic carbon (TOC), and total S. Mineralogy of the clay fraction (< 2 mm) was also studied by X-ray diffraction analysis, and partitioning of solid-phase Fe was performed by sequential extraction. Results and discussion The results obtained indicate important differences in soil composition at different depths and landscape positions, causing variations in physicochemical parameters, clay mineralogy, TOC contents, and iron geochemistry. The results also indicate that physicochemical conditions may vary in terms of different local microtopographies. Soil salinity was determined by relative position in relation to flood tide and transition areas with highlands. The proportions of TOC and total S are conditioned by the sedimentation of organic matter derived from vegetation and by the prevailing redox conditions, which clearly favored intense sulfate reduction in the soils (similar to 80% of the total Fe is Fe-pyrite). Particle-size distribution is conditioned by erosive/deposition processes (present and past) and probably by the positioning of ancient and reworked sandy ridges. The existing physicochemical conditions appear to contribute to the synthesis (smectite) and transformation (kaolinite) of clay minerals. Conclusions The results demonstrate that the position of soils in the estuary greatly affects soil attributes. Differences occur even at small scales (meters), indicating that both edaphic (soil classification, soil mineralogy, and soil genesis) and environmental (contamination and carbon stock) studies should take such variability into account.

The application of electron microscopy and microanalysis in conjunction with organic petrology to further the understanding of organic-mineral association: examples from Mount Isa and McArthur Basins, Australia

Organic petrology supported by electron microscopical and micro-analytical techniques was applied to organic matter in Proterozoic sediments to better understand hydrothermal processes responsible for ore-grade mineralisation. It was shown that organic maturation was not only closely linked to the geological history of the sediments, but also highlighted heat transfer by convection as differentiated from conduction solely through sediment burial and step-wise subsidence. Water-rock ratios effect organic maturation in hydrothermal systems, and erratic reflectance profiles are indicators of convective heat transfer. Identification and characterisation of organic materials in terms of source rock and migrated hydrocarbons was shown to be a powerful tool in reconstructing the thermal history of sediments, identifying hydrothermal episodes, fluid pathways and heat source in the northern Australian Proterozoic basins. Higher reflectance of organic matter towards the central parts of the Mount Isa Basin and some of the most northerly parts point to proximity to higher heat flow at times, in contrast to relatively low temperatures prevailing in the western parts of the basin, next to the Murphy Inlier. A close correlation shown between peak organic reflectance values and super-sequence boundaries farther highlighted the valuable information to be gained from organic petrology, by allowing the separation of processes responsible for metal dissolution and transportation from those inducing precipitation. (C) 2001 Elsevier Science B.V All rights reserved.

Nitrogen fertilization of coffee: organic compost and Crotalaria juncea L.

Information concerning the response of coffee to organic fertilizers is scarce. This study evaluates the effect of different doses of compost and Crotalaria juncea L. on growth, production and nitrogen nutrition of coffee trees. The treatments consisted of compost at rates of 25, 50, 75 and 100% of the recommended fertilization, with or without the aerial part of C. juncea. C. juncea was grown with NH4-N (2% 15N) and applied to coffee. The use of C. juncea increased growth in height and diameter of the coffee canopy. In the first year, the percentage of N derived from C. juncea reached 8.5% at seven months and 4.1% at fifteen months after fertilization. In the second year, the percentage of N derived from C. juncea reached 17.9% N at the early harvest, five months after fertilization. Increased rates of compost increased pH , P , K , Ca , Mg , sum of bases , effective CEC, base saturation and organic matter and reduced potential acidity. 15N allowed the identification of the N contribution from C. juncea with percentage of leaf N derived from Crotalaria juncea from 9.2 to 17.9%.

Comparison of different methods for the determination of total organic carbon and humic substances in Brazilian soils

ABSTRACTAiming to compare three different methods for the determination of organic carbon (OC) in the soil and fractions of humic substances, seventeen Brazilian soil samples of different classes and textures were evaluated. Amounts of OC in the soil samples and the humic fractions were measured by the dichromate-oxidation method, with and without external heating in a digestion block at 130 °C for 30 min; by the loss-on-ignition method at 450 °C during 5 h and at 600 °C during 6 h; and by the dry combustion method. Dry combustion was used as reference in order to measure the efficiency of the other methods. Soil OC measured by the dichromate-oxidation method with external heating had the highest efficiency and the best results comparing to the reference method. When external heating was not used, the mean recovery efficiency dropped to 71%. The amount of OC was overestimated by the loss-on-ignition methods. Regression equations obtained between total OC contents of the reference method and those of the other methods showed relatively good adjustment, but all intercepts were different from zero (p < 0.01), which suggests that more accuracy can be obtained using not one single correction factor, but considering also the intercept. The Walkley-Black method underestimated the OC contents of the humic fractions, which was associated with the partial oxidation of the humin fraction. Better results were obtained when external heating was used. For the organic matter fractions, the OC in the humic and fulvic acid fractions can be determined without external heating if the reference method is not available, but the humin fraction requires the external heating.