Water quality and plankton populations in an earthen polyculture pond

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Physical, chemical and microbiological aspects during the dry and rainy seasons in a pond covered by macrophyte used in aquaculture water supply

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Use of glass transition temperature for stabilization of board's cracks of Eucalyptus grandis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Evolução da biodegradabilidade da matéria orgânica em um sistema de lagoas de estabilização

Waste stabilization ponds (WSP) have been widely used for sewage treatment in hot climate regions because they are economic and environmentally sustainable. In the present study a WSP complex comprising a primary facultative pond (PFP) followed by two maturation ponds (MP-1 and MP-2) was studied, in the city of Natal-RN. The main objective was to study the bio-degradability of organic matter through the determination of the kinetic constant k throughout the system. The work was carried out in two phases. In the first, the variability in BOD, COD and TOC concentrations and an analysis of the relations between these parameters, in the influent raw sewage, pond effluents and in specific areas inside the ponds was studied. In the second stage, the decay rate for organic matter (k) was determined throughout the system based on BOD tests on the influent sewage, pond effluents and water column samples taken from fixed locations within the ponds, using the mathematical methods of Least Squares and the Thomas equation. Subsequently k was estimated as a function of a hydrodynamic model determined from the dispersion number (d), using empirical methods and a Partial Hydrodynamic Evaluation (PHE), obtained from tracer studies in a section of the primary facultative pond corresponding to 10% of its total length. The concentrations of biodegradable organic matter, measured as BOD and COD, gradually reduced through the series of ponds, giving overall removal efficiencies of 71.95% for BOD and of 52.45% for COD. Determining the values for k, in the influent and effluent samples of the ponds using the mathematical method of Least Squares, gave the following values respectively: primary facultative pond (0,23 day-1 and 0,09 day-1), maturation 1 (0,04 day-1 and 0,03 day-1) and maturation 2 (0,03 day-1 and 0,08 day-1). When using the Thomas method, the values of k in the influents and effluents of the ponds were: primary facultative pond (0,17 day-1 and 0,07 day-1), maturation 1 (0,02 day-1 and 0,01 day-1) and maturation 2 (0,01 day-1 and 0,02 day-1). From the Partial Hydrodynamic Evaluation, in the first section of the facultative pond corresponding to 10% of its total length, it can be concluded from the dispersion number obtained of d = 0.04, that the hydraulic regime is one of dispersed flow with a kinetic constant value of 0.20 day-1

Delays in stabilization or in reforms? The debt crisis

Empirical analyses attributing the 1980s' debt crisis to inconsistent stabilization policies rest on an inappropriate long-run approach. Revising this long-run approach yields opposite results: terms of trade shocks and foreign indebtedness explain this crisis, regardless of domestic stabilization policies. This prompts us to consider a new hypothesis, of delays in trade-policy reforms, with a model in which terms-of-trade variation (under shocks) is endogenous to export structure and efficiency of resource allocation. Evidence from the structural equations model shows that allocation distortions negatively affect changes in terms of trade, which then explain this crisis. A political economy extension demonstrates that income inequality and regional trade policy determine the distortions, which in turn leads to this crisis.

Caracterização do lodo de lagoa anaeróbia tratando resíduos esgotados de tanques sépticos e fossas com vistas ao aproveitamento

The sludge generated in stabilization ponds can be designed for various purposes, among them we mention agricultural use, recovery of degraded areas and civil construction. The choice of these alternatives should be made based on qualitative and quantitative characteristics of the sludge. In this context, this study characterized the digested sludge from an anaerobic lagoon in Cidade do Natal/RN, which deals exclusively with residues of depleted septic tanks and pits. The sludge showed levels of macro and micronutrients that confirm its potential for agriculture, with 139.49 g.kg -1 organic matter, 15.40 g.kg-1 nitrogen and metal concentrations below those required by Resolution No. 375/06 of CONAMA, besides the absence of fecal coliform and less than 0.15 viable helminthes eggs/g, on average. The particle size distribution showed that most of the particles have a diameter similar to the sand, allowing the replacement of this input, for example. Analysis of the leachate and of the sludge solubilized classified as non-inert and non-hazardous according to NBR 10.004/04. The volume produced in three years of operation by the pond was 1903.50m³, equivalent to approximately 400 kg of dry sludge. Overall, the concentrations of the parameters were similar to literature, although none of them addresses sludge anaerobic pond treating sewer from septic tanks and pits.The sludgepresents technical feasibility to various types of use, however the cost of dewatering and especially with transport can derail it. It needs to be made a more thorough study of the costs to prove its economic viability

Diagnóstico operacional de lagoas de estabilização

This work intends to develop an approach based through scientific criteria in the operational diagnosis of ponds of stabilization, starting from analyses accomplished in loco and in laboratory of 78 systems of sewer treatment through ponds of stabilization in the State of Rio Grande do Norte. The objectives of the research are: to map, to evaluate and to diagnose the operational acting of the ponds of stabilization of the state of Rio Grande do Norte, through visits in loco and analyses laboratory; to build a SIG, through the map rain, locate the points of releases of sewages of the systems of existent ponds in Rio Grande do Norte, as well as operational data and his/her respective efficiency diagnosis in the removal of BOD and Coliforms Termotolerantes; to evaluate, in real scale, three systems of ponds of stabilization of RN in the operational efficiency for the parameters BOD5, COD, pH, Temperature, OD and Coliforms Termotolerantes. Of 78 ETEs of appraised RN just, 9% or 7 had maximum concepts in what concerns the removal of BOD and Coliforms Termotolerantes and 41% or 32, they had the worst concepts in term of operational efficiency. The flowing concentrations ETEs of RN of BOD and Coliforms were of 410mg/L and 2,50x107UFC/100ml, the predominant configuration is of the type F1+M1+M2, the relationship BOD/COD revealed for the sewer tributary characteristic biodegradable high. For the study of case of 3 ETEs, the best operational efficiencies in decreasing order were: Cidade (Municipal district), it Roça (State) and São Miguel (SAAE). The removals of final BOD were 51,6mg/L; 108,27mg/L and 62,6mg/L, tends efficiency of 82%; 74% and 81%. In term of coliforms removal in the final effluentes were 1,90x103UFC/100ml; 1,50x104UFC/100ml and 3,10x104UFC/100ml, tends efficiencies of 99,99%; 99,95% and 99,90%. In what it concerns the practice of agricultural reúso of cultures consumed raw, none of 3 ETEs assisted the parameters of the Resolution CONAMA 357/05, for other reúso practices, all assisted the categories B and C of OMS. For release in body receiving ETE Cidade just, they assist the demands of the resolution of CONAMA 357/05, by study of purification solemnity of the receiving body. The maintenance lack and operation; exclusive operator in ETEs and operation knowledge was the contributory factors for the operational fall in appraised ETEs of RN

Enhanced stabilization of aerosol-OT surfactant monolayer upon interaction with small amounts of bovine serum albumin at the air-water interface

An investigation is made of the influence from small amounts of the protein bovine serum albumin (BSA) on the lateral organization of low molecular weight surfactant sodium bis-2-ethylhexyl sulfosuccinate (AOT) at the air-water interface. Surface pressure (pi - A), surface potential (DeltaV - A) and Brewster angle microscopy (BAM) experiments were carried out, with particular emphasis on the monolayer stability under successive compression-expansion cycles. AOT monolayer is not stable at the air-water interface, which means that the majority of AOT molecules go into the aqueous subphase as monomers and/or normal micelles. When a waiting time elapses between spreading and compression, the surfactant monolayer tends to reorganize partially at the air-water interface, with a monolayer expansion being observed for waiting times as large as 12 h. The incorporation of very small amount of BSA (10(-9) M) at the interface, also inferred from BAM, increases the monolayer stability as revealed by pi - A and DeltaV - A results. For a waiting time of circa 3 h, the mixed monolayer reaches its maximum stability. This must be related to protein (and/or protein-surfactant complexes) adsorbed onto the AOT monolayer, thus altering the BSA conformation to accommodate its hydrophobic/hydrophilic residues. Furthermore, the effects from such small amounts of BSA in the monolayer formation and stabilization mean that the AOT monolayer responds cooperatively to BSA. (C) 2004 Elsevier B.V. All rights reserved.

Modified stabilization method for the tibial tuberosity advancement technique: a biomechanical study

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Mechanical resistance of the modified stabilization method for the tibial tuberosity advancement technique: ex vivo experimental study in dogs

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Alterações no líquido sinovial do joelho de cães com osteoartrite induzida pelo modelo Pond e Nuki

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influence of root-surface conditioning with acid and chelating agents on clot stabilization

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Controlling factors of benthic macroinvertebrates distribution in a small tropical pond, lateral to the Paranapanema River (São Paulo, Brazil).

The aim of the present study was to examine the benthic fauna in a marginal pond lateral to the Paranapanema River and to identify the main controlling factors of its distribution. Considering the small size of the lacustrine ecosystem, we expected that seasonal variations of the benthic community attributes are more important than spatial variations; Methods: Two samplings, one in March and another in August, were carried out at nine sites in the pond. Sediment samples were obtained through a Van Veen grab for invertebrate sorting, granulometric analysis, and for quantification of organic matter in sediment. Other abiotic factors were measured, such as water transparency, dissolved oxygen, pH, electric conductivity, temperature, and depth of sediment sampling sites. Regarding the comparative analysis at spatial scale, no significant variations in density of the benthic invertebrate community were found. Results: In relation to the studied abiotic factors, only depth presented significant differences among sampling sites; All the measured environmental parameters presented significant differences among sampling months, except depth and the physical and chemical characteristics of the sediment. The abundance of Chaoboridae and Chironomidae was the unique attribute with a significant difference in comparing the two months. A higher abundance of taxa occurred in August, especially for Oligochaeta, Nematoda, Chaoboridae, and Chironomidae; Conclusions: Because of the low structural complexity of the studied pond, we concluded that the changes in benthic macroinvertebrate community attributes were mainly due to seasonal effects.

Haptic Stabilization of Posture in Adults With Intellectual Disabilities Using a Nonrigid Tool

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Niche occupancy and the relative role of micro-habitat and diet in resource partitioning among pond dwelling tadpoles.

We determined microhabitat and diet niche for tadpoles from two ponds in an agricultural landscape. Additionally, we verified the intraspecific variation in resource use, and if diet and microhabitat use were correlated. Tadpoles found in the two ponds differed in microhabitat use, because in the larger pond they explored deeper places far from the margin. There were three groups with high microhabitat niche overlap. In both ponds, plant cover was the best descriptor to explain interspecific variation in microhabitat use. Tadpoles of all species ingested mainly Bacillariophyceae and Trachellomonas however the diet differed intraspecifically in the species from the two ponds. Ten items in the temporary pond and 15 items in the permanent one were ingested by all species; however, the relative abundance of each item differed. Diet similarity was not correlated to similarity in microhabitat use. In this study, diet was as important as microhabitat use to explain resource partitioning.