José Paulo Soares de Azevedo

Assessment of the water quality monitoring network of the Piabanha River experimental watersheds in Rio de Janeiro, Brazil, using autoassociative neural networks

Water quality monitoring is a complex issue that requires support tools in order to provide information for water resource management. Budget constraints as well as an inadequate water quality network design call for the development of evaluation tools to provide efficient water quality monitoring. For this purpose, a nonlinear principal component analysis (NLPCA) based on an autoassociative neural network was performed to assess the redundancy of the parameters and monitoring locations of the water quality network in the Piabanha River watershed. Oftentimes, a small number of variables contain the most relevant information, while the others add little or no interpretation to the variability of water quality. Principal component analysis (PCA) is widely used for this purpose. However, conventional PCA is not able to capture the nonlinearities of water quality data, while neural networks can represent those nonlinear relationships. The results presented in this work demonstrate that NLPCA performs better than PCA in the reconstruction of the water quality data of Piabanha watershed, explaining most of data variance. From the results of NLPCA, the most relevant water quality parameter is fecal coliforms (FCs) and the least relevant is chemical oxygen demand (COD). Regarding the monitoring locations, the most relevant is Poço Tarzan (PT) and the least is Parque Petrópolis (PP).

Optimizing the operational conditions of a membrane bioreactor used for domestic wastewater treatment

This study evaluated the performance of a sidestream membrane module combined with an aeration system for the treatment of municipal wastewater. To investigate the membranes behavior and to control fouling, trials in laboratory units were conducted. In these tests, optimal values were established for some operational parameters, such as crossflow velocity, transmembrane pressure and air supply to continuously flush the membrane surface. Air supply improved the behavior of the permeate flux over time. After six hours operation, the stabilized flux was 35 L/m2.h at a total pressure of 0.40 bar (wastewater pressure of 0.05 bar and air pressure of 0.35 bar) and Reynolds Number of 4,600. All permeate samples analyzed indicated absence of fecal coliform and Escherichia coli.

Cobrança pelo uso da água no Estado do Rio de Janeiro, Brasil (2004-2013): histórico e desafios atuais

This article aimed to record the process of implementation of the charging system for water use in the territory of Rio de Janeiro State, since the pioneering experience of charging use in federal rivers (ANA-CEIVAP). In the following year, charging in Rio de Janeiro state waters configured a singular experience in the country, especially because it started simultaneously throughout the state. In spite of the claims initially directed to the implantation of the pricing process, in the last years the State has greatly improved in structuring a management model based on the committee-agency-collection tripod. The major challenges today are focused on two key aspects for the management of water resources: (i) to give agility/flexibility in the application of collected funds and (ii) to induce more rational water by public water services use in regions characterized by chronic shortages.

The JANUS structure: integrating data, models and preferences

In the realm of water resources management, new actors in Brazil are now involved in participatory decision making by means of water basin committees. This article proposes a decision-aid system, the JANUS structure, where the preference profiles of a water basin committee are blended with the technical evaluations performed by the basins agency. This approach allows for the ranking of the actions to be implemented in the water basin. The proposed interactivity in the computational implementation of the JANUS structure is aimed at enhancing perception of each criterion to be adopted for assessment, while providing the consequences of preference choices.In the realm of water resources management, new actors in Brazil are now involved in participatory decision making by means of water basin committees. This article proposes a decision-aid system, the JANUS structure, where the preference profiles of a water basin committee are blended with the technical evaluations performed by the basins agency. This approach allows for the ranking of the actions to be implemented in the water basin. The proposed interactivity in the computational implementation of the JANUS structure is aimed at enhancing perception of each criterion to be adopted for assessment, while providing the consequences of preference choices.

Uso de indicadores de perdas para seleção de um benchmarking entre as companhias estaduais de serviço de distribuição de água no Brasil

Tendo como referencia indicadores operacionais relacionados a perdas de agua e que constam na base de dados do Sistema Nacional de Informacoes sobre Saneamento (SNIS), baseados em resultados do ano de 2010, o presente estudo definiu criterios para o estabelecimento de parâmetros de avaliacao de desempenho operacional - benchmarking , e como estudo de caso utilizou dados referentes a 22 prestadores regionais de servicos de saneamento no Brasil, notadamente as companhias estaduais de saneamento. Complementarmente, a partir do agrupamento dos prestadores de servicos em funcao do atendimento ou nao ao benchmarking estabelecido, o trabalho compara o desempenho operacional de ambos os grupos, incluindo a avaliacao a luz de diferentes estratos populacionais, bem como ressalta os resultados obtidos pelos prestadores que atenderam ao benchmarking , durante o periodo compreendido entre aos anos de 2002 e 2009. Da base SNIS foram utilizados os seguintes indicadores operacionais e de acordo com os criterios estabelecidos obtiveram-se os valores de benchmarking: indice e micromedicao relativo ao volume disponibilizado (IN010) - 65,48%, indice de perdas no faturamento (IN013) - 24,10%, indice de perdas na distribuicao (IN049) - 33% - e indice de perda por ligacao (IN051) - 254,20 L.lig-1.dia-1. Dentre as 22 prestadoras analisadas, 4 atenderam ao benchmarking proposto. A avaliacao de desempenho dos prestadores de servico a luz dos estratos populacionais indica melhores resultados quando atendidos municipios de ate 20.000 habitantes. Em geral, os prestadores que atendem ao benchmarking estabelecido para o ano 2010 apresentaram resultados operacionais similares durante o periodo de 2002 a 2009.