A presente pesquisa analisa a relação das concentrações de metais em sedimentos de ambientes estuarinos com os fatores de degradação de bacias hidrográficas urbanas, tendo como estudo de caso o rio Imboaçu, em São Gonçalo, região metropolitana do Rio de Janeiro. O problema dessa bacia hidrográfica foi estudado considerando duas abordagens fundamentais: a análise laboratorial dos sedimentos presentes na foz do rio e o estudo dos fatores de degradação de bacias hidrográficas urbanas definidos por dados secundários. Os resultados de metais no sedimento indicam que a principal fonte de contribuição desses poluentes para o ambiente é através do esgoto sem tratamento, corroborando com os principais fatores apontados pela análise dos dados secundários.

Por diversos motivos, é possível a presença de ar nas tubulações de fornecimento de água e, consequentemente, que volumes de ar sejam contabilizados pelos hidrômetros. Esse fenômeno, além de ocorrer no Brasil, se apresenta também em países como Porto Rico, Peru e México. Existem à venda no mercado brasileiro equipamentos denominados “bloqueadores de ar” que, segundo os fabricantes, impedem a indevida cobrança. Porém, até o momento, não há uma norma específica nem literatura consolidada para aferição e certificação desses dispositivos. Nesse contexto, o presente trabalho teve por objetivo verificar o comportamento hidráulico dos bloqueadores de ar, a fim de servir como base para futuras discussões entre usuários, fabricantes e órgãos fiscalizadores sobre o adequado uso destes equipamentos. Nos testes experimentais realizados, foram obtidas as curvas perda de carga versus vazão para cinco bloqueadores avaliados. Como complementação, uma modelagem computacional permitiu verificar os possíveis efeitos causados no fornecimento de água. Os resultados mostraram uma grande variação dos valores de pressão mínima necessária para ocorrer o escoamento, desde 0,92 até 8,60 m.c.a., assim como das curvas de perda de carga, significando, em alguns casos, redução drástica da vazão da água fornecida. Como principal conclusão, observou-se a necessidade de uma regulamentação desses dispositivos para possibilitar a elaboração de instruções sobre o correto dimensionamento e uso em cada situação.

Anticipating and controlling transient response is a critical design activity for ensuring both safety and integrity of the operational subsea system. Predicting transient effect, commonly known as surge pressure, is of high importance for offshore industry. It involves detailed computer modelling that attempt to simulate the complex interactions between flowline and fluid, aiming at efficient flow assurance and consequently flowline and riser systems integrity. Bijupirá and Salema water injection systems, located in the Campos Basin, offshore Brazil, have been operating since 2003. The operational teams have raised concerns, whether the system is adequately designed to protect the subsea system against possible surge pressures during the event of sudden closure of a valve. Researches, referred to transient effects, clarify that is necessary to evaluate the system performance under current and desired operating conditions. The main goal of this paper is to predict the surge pressure in flowline and riser of the water injection system due to valve closure. A supplemental simulation has been performed in order to evaluate conditions that would keep the water injection surge pressure below Maximum Allowable Operating Pressure (MAOP) of the subsea equipments. According to the simulations results, the maximum surge pressure occurs throughout the manifold and jumper region, and the worst case occurs when all valves are simultaneously closed in Bijupirá and Salema production fields. The maximum surge pressures verified in simulations may reach values greater than the operating desired pressure, which may cause damage to the water injection system integrity. In order to avoid surge pressures greater than MAOP, which corresponds to 255 bar, the simulations indicated that when a pressure of 230 bar occurred on the turret, injection flow rate should not exceed 12000 bbl/day. Therefore, conventional techniques to solve complex problems in this area need to be improved, and computational simulations may contribute to establish the operating control system and guarantee its integrity during operating life.

Flooding in urban areas results mainly from both soil imperviousness and bad drainage projects. This means that without proper drainage and without adequate maintenance, floods always happen. On the other hand, traditional procedures applied to calculate urban drainage do not give good results when compared with advanced technologies available at universities and at research centres all over the world. Based on those considerations, this paper presents a computer simulation that aims to correct the Santo Antonio creek drainage problems, which is part of an urban basin located at the ocean zone of the city of Niteroi, in Rio de Janeiro State, Brazil. The software named "Sobek", developed by the WL-Delft Hydraulic Institute, was applied to simulate the proposed drainage networks. The results show that it is possible to avoid flooding by constructing on site reservoirs to retain part of the rainwater. It was suggested that 2400 litres of rainwater per residence was stored in order to reduce the runoff. Keywords: urban drainage, computational simulation and flood control.

Predicting transient effects, known as surge pressures, is of high importance for offshore industry. It involves detailed computer modeling that attempts to simulate the complex interaction between flowline and fluid in order to ensure efficient system integrity. Platform process operators normally raise concerns as to whether the water injection system is adequately designed in order to be protected against possible surge pressures during sudden valve closure. This report aims to evaluate the surge pressures in Bijupirá and Salema water injection systems due to valve closure, through a computer model simulation. Comparisons among the results from empirical formulations are discussed and supplementary analysis for the Salema system was performed in order to define the maximum volumetric flow rate that the design pressure was able to withstand. Maximum surge pressure values of 287.76 bar and 318.58 bar, obtained using empirical formulations in Salema and Bijupirá respectively, have surpassed the operating pressure design, while the computer model results have shown the highest surge pressure value to be 282 bar in the Salema system.