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

Remoção de matéria orgânica em sistemas de lagoas de estabilização no Nordeste brasileiro

Stabilization pond is the main technology used for treatment wastewater, in northeast Brazil, due to lower cost of deployment, operation and maintenance compared to other technologies. Most systems of stabilization ponds has been in operation for some time, on average 10 years of operation, receiving high organic loads and do not have good removal efficiencies of the main parameters for which have been designed. Therefore it is necessary to work to quantify the efficiency of current systems. This study evaluated the biodegradability of organic matter in raw sewage, the removal of organic matter in reactors and determination of the kinetic constant removal of organic matter (k), both in reactors and in raw sewage, based on the analysis made in the laboratory and through mathematical methods proposed in the literature, in nine systems stabilization ponds, located in Rio Grande do Norte. In relation the degradation kinetics in stabilization ponds, it was observed that many papers published in the literature were obtained in pilot-scale systems, which often, due to the action of external factors such as wind and temperature, these can t be considered as a reference in the analysis of the kinetic constant K, so the need for more research into systems of scale. This study had three distinct phases and simultaneous, routine monitoring, study of the daily cycle and the determination of kinetic constant of degradation of organic matter (K). The monitoring showed that the removal efficiencies of organic matter on most systems were lower than suggested by the literature, the best efficiencies of around 76% (BOD) and 72% (COD) and the worst of the order of 48% (BOD) and 55% (COD). The calculation of K in raw sewage (Ke) was within the range of variation expected in the literature (0.35 to 0.60 days-1). Already for the results obtained for K in the reactors (Kr), there were well below the values recommended in the literature (0.25 to 0.40 d-1 for complete mix and from 0.13 to 0.17 d-1 for flow dispersed), in line with the overloads that organic systems are subject

Avaliação da eficiência da remoção de matéria orgânica e microbiológica de três sistemas de lagoas de estabilização em série na Grande Natal-RN: Beira Rio, Jardim Lola I e Jardim Lola II

Waste stabilization ponds are the main technology in use for domestic sewage treatment in Rio Grande do Norte State (RN), northeast Brazil. The are around 80 systems, constructed mainly by municipal city halls, being series comprised by a primary facultative pond followed by two maturation ponds the most used configuration. Due to problems related with the production and destination of sludge and generation of bad odors, the designers have avoided the use of anaerobic lagoons. The majority of systems are rarely monitored to verify their efficiencies and to get new project parameters for future designing. This work has as purpose to make a diagnosis of efficiency of three series of waste stabilization pond series (WSPS) of Jardim Lola 1, Jardim Lola 2 and Beira Rio, located in the North Zone of the city of the Natal/RN, treating domestic raw sewage, on the removal of organic matter and thermotolerant coliform, comparing the operational conditions of the systems this inside of the bands foreseen in the project, through parameters BOD5, QOD, thermotolerant coliforms, dissolved oxygen, pH, temperature, ammoniac nitrogen, total and suspended solids. The work was carried through in the WSPS, all constituted by a primary facultative pond followed by two maturation ponds. Socioeconomic characteristics of population are predominantly low and all the plants are very near of the contributing basins. The series were monitored from of May the November of 2002, totalizing 20 collections of grab samples of raw sewage and ponds effluents between 8:00 and 9:50 h. The main aspect to be detached by the results was the great concentration of organic matter (BOD and COD) and microorganisms the raw sewage which were around two times more concentrated than those values foreseen one in project. Considering all series the highest removals of organic matter were observed in system Beira Rio (84 and 78% of BOD and COD, respectively), which presented high hydraulic detention time (TDH = 89 days). On the other hand, Jardim Lola 1 and Jardim Lola 2 presented a much lower values of HDT (36 days and 18 days respectively) and their removals of BOD and COD were the same (76% and 60%, respectively). The Beira Rio WSPS, was the most efficient verified in relation to solids and ammonia, proving the great influence of the operational variables such as HDT and applied surface organic loadings on the performance of pond series. Although the treatment plants have reached efficiencies of thermotolerant coliforms around 99,999%, the concentrations in the final effluent can be considered very high for launching in aquatic bodies, particularly those produced by Jardim Lola 1 and Jardim Lola 2 series

Efeitos da previdência rural na agricultura familiar da microrregião Serra de São Miguel - RN

The objective of the present work is to verify the effects of Rural Social welfare in the family agriculture of the microrregião Serra de São Miguel-RN. The study based on available bibliography on the theme, in secondary data and in a rising amostral accomplished in three municipal districts (Encanto, São Miguel and Riacho de Santana) of the microrregião. The universe of the study was the establishments of the family agriculture appeared in the Agricultural Census of 2006, in those municipal districts. The unit of considered analysis was the rural family, with the interviews being applied close to the farmers' families with and without retired rural. The sample was of 94 present families in the family establishments. The results demonstrate that the Rural Precaution reaches a significant covering degree in the rural area of the researched municipal districts, with an average of 1,57 beneficiaries for home in the families with retired. The data of the research attest that the family agriculture in the microrregião Serra de São Miguel-RN it has few favorable conditions for his/her development, once, besides the shortage of lands and of the climatic factor of the area, the returned public politics the family farmers' totality - like PRONAF and PAA -, it has been unable to give effective answers for the improvement of the life conditions in the rural way, have seen the minimum amount of families reached by those politics, be in function of the drawing or of the atmosphere where they are done. In this context, he/she stands out the importance of the Rural Precaution that, in function of the application of the constitutional devices that you/they guaranteed his/her universalization, it has been the only relevant public politics that, in fact, it has been reaching her/it all their beneficiary potentials. Given the general situation of the family agriculture of the microrregião and of the specific characteristics of the researched family establishments, the hypothesis was corroborated that the rural retirement doesn't contribute directly to the increase / making possible of the family agriculture. In spite of 57,4% of the families with retired have declared to use resources of the retirement in the costing of the rural activity carried out by the family, the annual medium value of the expense just located around 7,02% of the annual value of the retirements gained by the families in the year of 2010. Data the low levels in that the social reproduction of the great majority of the family establishments of the microrregião, the maintenance of the families is operated represents the main destiny of the resources precautions. It was also confirmed the hypothesis that the Rural Precaution constitutes the main monetary contribution of the families with retired. For more than 93% of the families with retired, the retirements doing 50% or more of the total of the family monetary income, and in the composition of the rural income of the families with retired and pensioners, the originating from income the rural retirements are equal to 65,24% of the total of the annual income obtained by the families. It is ended, because, that the rural precaution, given to the adversities for the development of the family agriculture, of the operational inefficacy of the public politics and of the few opportunities of generation of existent income in the local savings, it is the main responsible for the reduction of the poverty and, consequently, for the improvements of the conditions of life of the families of and with seniors in the rural way of the microrregião Serra de São Miguel-RN

Caracterização do sistema agropecuário dentro da agricultura familiar como subsídio de políticas públicas

The objective of this study was to characterize the socioeconomic profile of the family farmers who live and work in Brazilian rural space and highlight the importance of family agribusiness through the significant relation between some variables as the value of the total production, GDP share in total area of the establishments, agricultural production and farmer income, that show the important participation of these farmers in agricultural productivity and consequently on the economy of country. Therefore, this sector deserves a greater attention and more investment in the development of public policies that lead to a quality education in rural areas, availability of technical courses for farmers, technical assistance more efficient and effective, as well as funding more readily available

Trabalho infantil na agricultura :sentidos produzidos pelas mês e pelos professores

Attempts to explain child labor, for the most part, have been reduced to the economic aspect, looking to establish a causal relationship between work and poverty. Without disregarding this aspect, we intend to approach this phenomenon considering other aspects that could be contributing towards its maintenance. We seek, above all, to articulate it with the concepts of disciplinary power and ideology. The present study, therefore, tries to consider these aspects with the intention of learning the reasons that the mothers and the teachers produce concerning child labor in the cultivation of vegetables. We elected these participants because we considered that child labor has been reinforced by the disciplinary institutions and proponents of ideology, the family and the school, here represented, respectively, by the mothers and the teachers. To affect this study, we created focused groups with the mothers whose children are students and work in the cultivation of vegetables in Gramorezinho (neighborhood situated in the northern part of Natal, RN) and with the teachers of the neighborhood school (Escola Lourdes Goudeiro). The discussion of the participants was handled according to the perspective of discursive practices, attempting to articulate them with the notions of ideology and disciplinary power. In general, we perceived how much ideology and discipline are immersed in the discursive practices of the participants. Whereas, even though in some moments the reference to work as being something that takes time from the child to study and play is apparent, the participants attribute great importance to child labor. Both for the teachers and for the mothers, work is something that can free the children from laziness, from becoming criminals and from using drugs. It too constitutes an important alternative to idleness and to the permanence of the child in the streets

Avaliação da influência da matéria orgânica, na determinação quantitativa de metais em amostras de sedimento, por espectrometria de absorção atômica e análise de metais traços por fluorescência de raios-X

The proposal of this work is to evaluate the influence of the organic matter on the results of the analyses of the metals (Zn, Pb, Al, Cu, Cr, Fe, Cd e Ni) for Atomic Absorption Spectrometry (AAS), so much in the extraction stage as in the reading using for that the chemometrics. They were used for this study sample of bottom sediment collected in river Jundiaí in the vicinity of the city of Macaíba-RN, commercial humus and water of the station of treatment of sewer of UFRN. Through the analyses accomplished by EAA it was verified that the interference of the organic matter happens in the extraction stage and not in the reading. With relationship to the technique of X Ray Fluorescence Spectrometry (XRFS), the present work has as intended to evaluate the viability of this technique for quantitative analysis of trace metals (Cr, Ni, Cu, Zn, Rb, Sr and Pb) in having leached obtained starting from the extraction with acqua regia for an aqueous solution. The used samples constitute the fine fraction (<0.063 mm) of sediments of swamp of the river Jundiaí. The preparation of tablets pressed starting from the dry residue of those leached it allowed your analysis in the solid form. This preliminary study shows that, in the case of the digestion chemistry partially of the fine fractions of bottom sediments used for environmental studies, the technique of applied EFRX to the analysis of dry residues starting from having leached with acqua regia, compared her it analyzes of the leached with ICP-OES, it presents relative mistakes for Cu, Pb, Sr and Zn below 10%

Análise das dificuldades de aprendizagem numa disciplina de química orgânica do curso de química na modalidade à distância da UFRN

In today`s society the use of so-called information technology and communication (ICT), is promoting a revolution in the forms of teaching and learning through the methods of distance learning courses, especially in higher education. Studies show that students in this way have great difficulties in the learning process, especially when dealing with experimental subjects that require high power of abstraction as chemistry. The goal of this work is to promote improvement in the teaching and learning in the discipline Chemistry of Life offered for the Bachelor`s Degree in Chemistry in distance UFRN. For this we analyzed evidence of the semester 2011.2, in order to identify what are the main difficulties of the students on the assessments. That`s why video lessons related to matters that create the majority of difficulties for students were developed, the final product this work. Being obtained the improvements by video classes in the learning process of the students, from a questionnaire answered by the students in the virtual learning environment, and from their success rate at the end of the course

Considerações sobre metodologia interativa aplicada à disciplinas de química orgânica de alguns cursos da UFRN

The aiming of this work is linked to chemical education, focusing organic chemistry classes of Chemical Engineering, Pharmacy and Zootechny graduate courses of the Federal University of Rio Grande do Norte. For that, teaching-learning process related to basic chemical subjects which support the understanding of organic chemistry concepts was evaluated in a research period of two years. The education proposal linked to the theoretical content of the cited classes, pointed out the process of knowledge construction, in which educational commitment as well as dedication in the teaching-learning process was also valued. In that approach several didactic tools were applied, among them scientific articles were used as supplementary studies of the basic organic chemistry concepts and related. The acceptability of students, as well as their motivation, performance and learning process was justified by the data collection of the applied teaching methodology. The acceptability and commitment of the students facing this teaching interactive approach, which transversely contributed to the intellectual maturity growth of the students, as well their professional development, were evidenced by satisfactory obtained results that will be herein discussed

Os caminhos da transição agroecológica: uma análise das experiências da agricultura familiar camponesa no território dos Vales do Curu e aracatiaçu-CE

This study examines peasant family farming from an agroecological perspective. It intends to analyze the changes resulting from the transition from conventional to agro-ecological agriculture in the daily practices of farmers articulated associated with the Network of Agroecological and Solidarity Farmers of the Curu and Aracatiaçu Valleys Territory, the locus of this empirical research, and a space which has highlighted the social dynamics of agroecological innovation, as well as articulating environmental exchanges and knowledge development. As a way to further that goal, we seek to identify the forms of social organization previously present in the daily lives of these subjects, in addition to grasping the determinants that lead or led them to adopt agroecology, noting the need to verify the forms of resistance, and the strategies adopted by farmers and how they articulate collectively. Through the historical and dialectical methods, we seek to take the implications of technical modernization of agriculture under the conditions of production and reproduction of peasants and thus situate the emergence of agroecology, a focus that is born as a counterpoint to conventional patterns of agricultural development based on the paradigm of the Green Revolution. We structured this study around the trajectory of agroecological farmers that developed and internalized agroecological practices, processes, and organizational forms. For the analysis, we used theoretical and methodological frameworks from literature related to field research. The systematization and analysis of experiments revealed that agroecological transition is a broad process of change, not restricted to technical matters. We observed changes in production practices, diversification of production and feeding practices, ecological awareness, production autonomy, and organizations formed to face the challenges resulting from the imposition of the dominant agricultural development model that combines environmental degradation, land ownership concentration, and wealth concentration

A agricultura familiar do Seridó potiguar: vulnerabilidade, percepção e adaptação às mudanças climáticas

At the semiarid regions of developing countries the rural population has always been vulnerable to the climatic variations e its consequences. The effects of the semiarid climate, together with other biophysics, social and political-economic factors, impair the agricultural production, generating a situation of food insecurity and poverty in the rural areas. With the occurrence of climate change, natural resources of the semiarid regions can became scarcer, what would directly affect the agricultural production and those who depend on it. Therefore, the present study sought to study one of the most susceptible areas to the effects of the semiarid climate and desertification of Rio Grande do Norte, the potiguar s Serido. The study aimed to analyze the socioeconomic and environmental factors that put farmers in a position of vulnerability to the effects of climate; assess their perceptions about climate variations that have already occurred and their knowledge about climate change and global warming, also to identify which adaptation strategies to climate they have adopted at the rural establishment. The survey was conducted in 29 communities of four counties of the potiguar s Serido Caico, Parelhas, Lagoa Nova and Acari. Semi-structured interviews were conducted with local leaders and 241 questionnaires were applied with the family farmers. It was found that in addition to environmental factors such as the scarcity of water resources and climatic conditions, other factors such as the environmental degradation, the small size of the properties, the lack of technical assistance and financial resources and also the low education levels reduce the resilience capacity of family farming to the effects of the Semiarid climate. With the occurrence of climate change, the challenges for family farming at Serido will intensify. If farmers cannot adapt, the impacts may preclude this category of agricultural production causing serious harm to food security and further increasing the vulnerability situation of these populations. Although the farmers perceived changes in climate, the lack resources and information appears as the main reasons preventing the adoption of adaptation strategies. The lack of knowledge about climate change and global warming and the impacts that these phenomena may cause are also limiting factors for adaptation. It is therefore essential to identify the factors that influence the adoption of adaptation strategies, and seek alternatives to living with the semiarid that can strengthen the resilience of family farming and social reproduction that allow agricultural segment, even in a climate change scenario

Globalização da agricultura e concentração fundiária no município de Ipanguaçu-RN

This research talks about the insertion of the borough Ipanguaçu-RN on the agricultural globalization process from 1979 to 2003. At the first moment (1979-1992) with the construction of the Açu´s barrage and the entry of agricultural national enterprises and secondly (1993-2003) with the entry of the multinational Del Monte Fresh Produce enterprise. During all this insertion period the impacts on the local land market. To make the research operational, it was tried to analyze documents of the local registry office and all the local, national and international bibliography about this issue during all the study period. Furthermore, interviews were made. At the ending of this thesis, the results show intensification of the agricultural capitalization on this borough, changing of the productive axis which heads to the external market and the land concentration of this borough. It was concluded that the insertion of this borough in the globalization system will increase the external intervention on Ipanguaçu blocking, then, the access if the local population to the land

Agricultura familiar integrada ao mercado: mediação política e transformações socioespaciais no assentamento rural Vale do Lírio/RN

It s an application about the development of the family agriculture integrated to the market in which is detected the development of the relation of partnership between settled of agrarian reform and the capitalist enterprise. It s shown initially, a conceptual discussion about family agriculture, watching the historical contexts that characterize the expropriation and subordination of the category. This way, the family agriculture is contextual zed in the moment of the modernization of the agriculture, he rising of the social tension in the area of the restructuration of production and the globalization. Finding to understand the agrarian question in Rio Grande do Norte, it s characterized the acting of the state in promoting agrarian reform politics and redistribution of lands. This way, the research demonstrate the reality of the settled of Vale do Lírio, with the partnership of the Caliman Company S. A. in this context, it s emphasized the social geographic transformation in the settler. This way it was realized the analysis of the survey of data in a lot of public department, and the research of the area with use of application form, in 90% percent of the researched group, with interviewing with the leaders of this group and with the manager of the Company. The research demonstrates an analysis of the reality lived by this group, in the perspective the interests of the government and the capital.