Counseling Brazilian Farmers on Their Management Activities

The study identified some reasons that explain the limited use of scientific management tools by Brazilian farmers. A matrix of management activities was built to classify these reasons. Primary data used in the study were collected during two phases. During the first, 8 focus group manned by cash crop farmers, beef cattle farmers, and extension agents and counselors, were used to produce qualitative information. During the second phase, quantitative informations were collected via a survey with 494individual questionnaires applied to the same public covered by phase one. For the statistical tests performed 95% of significance was required. Some conclusions of the study are: (1) farmers differ significantly from extension agents or counselors on farm management subjects; (2) farmers do not alter their strategic production plans in response to price changes or other signals perceived as short or mid term movements due to costs of changes in their production processes; (3) in organizing their human resources structure farms tend to concentrate into their hands amounts of responsibilities larger than they can handle; (4) in organizing their financial flows there is a large gap between the desired level of details and their abilities to collect the data; and (5) the major difficulties faced in the function of controlling are linked with problems of collecting data. This is due to low levels of formal education that characterize the farm-hired labor.Brazilian farm management, counseling farmers, matrix of management activities., Farm Management, Teaching/Communication/Extension/Profession,

Monitoring denitrification by means of pH and ORP in continuous-flow conventional activated sludge processes

Indirect signal analysis (pH, ORP and DO) are often used in monitoring and control of SBRs (Sequencing Batch Reactors), where operating conditions can be clearly identified during the various cyclic phases. Only few studies applied this methodology to control continuous flow plants, as it is much more difficult to identify operating conditions because of continually variable inflow characteristics. This work applied indirect signal analysis to control pre-denitrification in continuous-flow activated sludge processes: (i) a laboratory-scale plant, fed with synthetic wastewater, simulating real municipal wastewater and (ii) a pilot-scale plant, fed with real sewage. Three different ranges of ORP values identify three operational conditions of the denitrification process. (1) ORP > 0 mV means that nitrates and/or nitrites are present, possibly due to a low C/N ratio. (2) –50 < ORP < –200 mV is typical of normal operating conditions, that is with a balanced C/N ratio. (3) ORP < –350 mV means that oxidized nitrogen load is too low or that C/N exceeds the stoichiometric ratio. The trend of pH, instead, points out if and how the process is evolving from one to another operating condition. The correlation between pH and ORP signals (as well as their derivatives) allows to restore normal operating conditions by acting on the internal recycle flow-rate. Improved denitrification process ensures lower effluent nitrate concentration, and reduce external carbon dosage to achieve stricter nitrogen limits

Nitrogen removal in fixed-bed submerged biofilters without backwashing

The paper reports the findings of four years of pilot-scale research on nitrogen removal in fixed-bed biofilters fed on real raw municipal wastewater. The plant was made of two fixed-bed biofilm reactors in series with an intermediate settling tank from which excess biomass from the first stage was discharged. The first filter was used for carbon removal either with oxygen or nitrates. The second filter was used for nitrification. The average nitrification rate at 20°C was 0.84 gNH 4 + -N m −2 d −1 with 5 mg l −1 dissolved oxygen in the bulk liquid. Temperature dependence was calculated (r n = r n,20° 1,05 T-20 ). The influent organic load strongly affected ammonia oxidation. If the organic loading exceeded 2.5 gCOD m −2 d −1 nitrification rate was reduced by 50%. Denitrification was performed by recycling nitrates back from the second filter and by using sewage itself as carbon source. Denitrification rate showed to be strongly dependent on temperature (r d = r d,20° 1.11 T-20 ) and on the recycle rate. Hydrolysis of the colloidal COD fraction showed a similar dependence on both temperature and recycle rate. Therefore, it has been concluded that the hydrolysis of finely dispersed COD particles can be the limiting step of denitrification in the biofilter when real sewage is used as carbon source

Performance of electro-osmotic dewatering on different types of sewage sludge

The feasibility of pressure-driven electro-dewatering (EDW) on sludge samples taken after different biological processes, stabilisation methods or mechanical dewatering techniques was assessed. First, the influence of potential values on EDW of anaerobically and aerobically stabilised, mechanically dewatered, sludge samples was investigated. Preliminary tests carried out by applying a constant potential (10, 15 and 20 V) in a lab-scale device confirmed the possibility to reach a dry solid (DS) content of up to 42.9%, which corresponds to an increase of 15% of the dry content in dewatered sludge without the application of the electrical field. Dewatering increased with the applied potential but at the expense of a higher energy consumption. A potential equal to 15 V was chosen as the best compromise for EDW performance, in terms of DS content and energy consumption. Then, the influence of the mechanical dewatering was studied on aerobically stabilised sludge samples with a lower initial DS content: the higher initial water content led to a lower final DS content but with a considerable reduction of energy consumption. Finally, the biological process, studied by comparing sludge samples from conventional activated sludge and membrane bioreactor processes, didn’t evidence any influence on EDW. Experimental results shown that DS obtained after mechanical dewatering, volatile solids and conductivity are the main factors influencing EDW. Anaerobically digested sludge reached the highest DS content, thanks to lower organic fraction

Complete autotrophic process for nitrogen removal from inkjet printing wastewater

Lab-scale results on the treatability of ammonium-rich wastewater from textile digital printing highlight the feasibility of an innovative biological process, based on purely autotrophic bacterial populations: ammonium oxidising bacteria (AOB) and anaerobic ammonium oxidisers (AAO). Activity of AOB has been measured through pH/DO-stat titration and that of AAO has been assessed through manometric tests, on raw mixed wastewater coming from textile-print factories (0.5 to 0-6 gN/L as ammonium nitrogen). AOB activity showed a reduction of 20-40% if compared with maximum activity on a synthetic medium. AAO activity tests showed a residual specific maximum anammox activity (SAA) of 0.1-0.4 gN2-N/gVSS/d, 40-60% of the control values obtained with synthetic wastewater. Activity tests confirmed treatability of the textile wastewater by AAO. Tests have been performed also on concentrated wastewater (2 to 3 gN/L as ammonium nitrogen) from the first rinsing bath. In this case, strong inhibition (between 80 and 100%) of anammox activity was observed. Careful operation of a continuous-flow completely mixed bioreactor can overcome this drawback, as pH and effluent ammonium concentration in the reactor are controlled

Editorial: Ecotechnologies for Wastewater Treatment - Impacting the environment with innovation in wastewater treatment

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AVALIAÇÃO DA EFICÁCIA DE PROGRAMA DE FORMAÇÃO DE EMPREENDEDORES E LIDERANÇAS RURAIS NO ESTADO DO PARANÁ

Este artigo apresenta os resultados de avaliações da eficácia do Programa Empreendedor Rural – PER – em alcançar seus objetivos. O PER é um programa de educação rural para produtores e trabalhadores rurais desenvolvido no Paraná e executado pelo Senar/PR e Sebrae/PR que visa elevar os estoques de capital humano e social no meio rural. O programa adota o construtivismo como método de ensino e a elaboração de projetos de investimento como eixo de aprendizagem. Na Fase I do Programa, executado a partir de 2003, o objetivo principal é a promoção de empreendedorismo no meio rural, por meio de um treinamento com cerca de 5 meses de duração. A Fase III, executada a partir de 2005, tem como objetivo principal a ampliação do capital social no meio rural, e se desenvolve por cerca de 9 meses. A avaliação do programa foi planejada para coletar informações em três fases distintas: (1) início do programa (Marco Zero), (2) término do programa e (3) após um ano do término do programa. O programa foi avaliado por meio de questionários e entrevistas estruturadas, em amostras de participantes estatisticamente significativas. Aos resultados foram aplicados métodos de estatística descritiva, teste de Qui-quadrado, apresentação gráfica de dados e a técnica de “data mining”. Os resultados para a Fase I mostram que o programa foi eficaz na promoção de empreendedorismo, especialmente na criação de negócios próprios pelos participantes um ano após a conclusão do treinamento, entre outros resultados. Para a fase III a avaliação mostra que, ao final do treinamento, que implica na elaboração de projetos associativos, os participantes tiveram uma visão mais crítica e real do seu efetivo estoque de capital social. O programa contribuiu como ponte para a rede social existente, mas não foi suficiente em si mesmo para gerar um aumento no capital social das comunidades.---------------------------------------------The paper presents results of evaluations of the effectiveness of the Agribusiness Management Program - PER - in reaching its objectives. The PER is a rural educational program for producers and managers developed in the state of Paraná. Senar/PR and Sebrae/PR are in charge of the program execution that aims at raising the supplies of human and social capital in the state rural areas. The program uses a constructive approach as educational method and the elaboration of investment projects as its learning alignment. The Phase I of the Program, executed since 2003, aims at empowering rural entrepreneurship, by means of a training program with 5 months duration. Phase III, executed since 2005, has as major objective increasing the stocks of social capital in the state rural areas and its learning program lasts about 9 months. The evaluation of the program was planned to allow collecting information in its three distinct phases: (1) at beginning of Phase I of the program (Landmark Zero); (2) at the end of Phase I; and (3) after one year of the end of Phase I of the program, for each group of participants. The program was evaluated by means of questionnaires and structuralized interviews, with statistically significant sample of participants. Methods of descriptive statistics, tests of Qui-square, graphical presentation of data and the technique of “date mining” were applied to analyze the answers. The results for Phase I show that the program was efficient in promoting entrepreneurship, especially in the creation of business-oriented projects for the participants. They were, among others results, observed to be implemented one year after the conclusion of the Phase I training. The evaluation process showed that at the end of Phase III training, that required the elaboration of an associative project by the participant, they had a more critical and real vision of the effective stock of social capital in their area. The program built a bridge for the existing social network, but it was not enough in itself to generate an increase in the stock of social capital for the communities.educação rural, empreendedorismo, capital social, liderança, eficácia de capacitações, rural education, entrepreneurship, social capital stock, leadership, effectiveness of qualifications, Agribusiness, Teaching/Communication/Extension/Profession,