José Saldanha Matos

• Technical University of Lisbon

Sustainability seeks to strike a balance between preserving the environment and meeting human needs without compromising future generations. In this context, and considering the effects of climate change on water availability, water reuse is emerging as an alternative to conventional water sources for various purposes, contributing to sustainabilit...

In Africa, the urban population and informal settlements are increasing, resulting in additional public health and environmental risks and challenges related to the need for basic and sustainable infrastructures and services. In Maputo, the capital of Mozambique, at least 80% of the city is composed of informal settlements, and although some areas...

In Africa, the urban population and informal settlements are increasing, resulting in additional public health and environmental risks and challenges related to the need of basic and sustainable infrastructures and services. In Maputo, the capital of Mozambique, at least 80% of the city is composed of informal settlements, and although some areas a...

Sustainable drainage approaches differ from traditional design approaches to manage flooding risks, where runoff is regarded as a nuisance, instead of considering surface water as a valuable resource that should be managed for maximum benefits. Nature-based solutions (NBS) may deliver numerous services including supporting biodiversity, climate reg...

Resilience theory has gained significant traction in various urban fields, including natural disasters and risk management or climate change adaptation, and at different organizational levels, including academics, practitioners, and policymakers. It should be considered a complementary approach to sustainable development that enhances cities’ capac...

Flooding is a truly ubiquitous problem. Today, it puts an estimated 1.81 billion people at risk. Floods particularly affect coastal cities, where it is expected that the damage associated with inundations exceed the staggering value of USD 50 billion by 2050. Indeed, the risk associated with flooding in coastal cities is increasing due to three une...

Green roofs are low-impact development (LID) that assist in regulating stormwater runoff by reducing the peak flow rate and total runoff volume, among other benefits. In this study, the hydraulic performance of green roofs was modeled using the SWMM 5.2 software, taking field data into account for calibration purposes. A Storm Water Management Mode...

Safely managed sanitation is indispensable for societies to ensure public health, environmental protection, and economic and social development. This could be achieved, in large areas of the world, through dry sanitation systems. Dry sanitation systems are especially used in water-scarce regions and low-income households. In dense peri-urban areas,...

Water scarcity is a driver for society to rethink water management and change the paradigm of use to a fit-for-purpose approach—i.e., separating potable water for human consumption (drinking, cooking or personal hygiene) from all non-potable uses that do not require the same quality level. In this context, urban water reuse is a relevant tool for m...

O aumento do consumo de água em Cabo Verde devido à crescente procura para abastecimento público, industrial, agrícola e turístico, exerce uma pressão significativa sobre os escassos recursos hídricos nacionais disponíveis. O Governo tem investido na última década numa grande reforma legislativa do sector da água e saneamento que advoga, como um do...

In this paper, the hydrological performance of eight pilot green roofs (GR) installed in Lisbon, Portugal, under a Mediterranean climate is analyzed. The pilot units were installed at Instituto Superior Técnico campus of Lisbon University. The pilots present different plant species and different substrate types, with some of the units incorporating...

Urban pluvial floods are the outcome of the incapacity of drainage systems to convey the runoff generated by intense rainfall events. Cities have been struggling to control such hazards due to several pressures, such as urbanization increase, more frequent experiences of extreme rainfall events, and increases in tide levels. Such pressures demand t...

Ageing infrastructure are a concern for many wastewater utilities. This is accentuated with the presence of hydrogen sulfide within the sewer headspace, known to induce concrete corrosion, toxicity and odours. Some industrial effluents contain significant sulfide concentrations, however most field studies in the literature refer to domestic network...

Nature-based solutions (NbS) are increasingly recognized as viable tools for sustainable urban water management. This article explores the implementation of NbS in two distinct cities, Singapore and Lisbon, to demonstrate that NbS can work in very different contexts and spark new thoughts on the urban–nature relationship and to identify commonaliti...

Currently, in sub-Saharan African countries, 65 to 100% of the urban population is served by on-site sanitation systems, typically pit latrines and septic tanks. Faecal sludge dewatering in drying beds is one of the most commonly adopted low-cost treatment technologies in developing countries due to favourable climate conditions in terms of tempera...

In this paper, an expedited multi-criteria decision analysis framework, capable of tackling several dimensions for the choice of sanitation services, at an early planning stage is presented. The approach combines geographic information systems aided analysis for onsite solutions, with a multi-criteria decision analysis tool capable of suggesting an...

Intense rainfall events combined with high tide levels frequently result in urban floods in riverine or coastal cities. Their increasing variability and uncertainty demand urgent but sustained responses. Thus, resilience-driven approaches are emerging in contrast to the traditional technical-economic frameworks, as urban resilience reflects the ove...

Urban environments are challenged with unprecedented anthropogenic and natural pressures, the latter being accelerated by the growing awareness of the consequences of climate change. The concept of urban resilience has been growing in response, since it allows us to understand city behaviour as a system of systems, improving its response to extreme...

This study was carried out to evaluate the effect of natural ventilation and intermittent pumping events in hydrogen sulfide and methane dynamics, in terms of system operation and risk of gas exposure. Work was conducted in a full scale gravity sewer downstream of pumping stations, in Portugal. Different ventilation rates and locations were assesse...

The work presented herein was carried out to assess the effect of intermittent pumping events in sewer headspace pressure differentials, as well as their relationship with hydrogen sulfide gas concentration. A full scale gravity sewer in Portugal, located downstream of several pumping stations, was used as the guiding case study. Under normal syste...

Gas pollutants emitted during wastewater transport contribute to atmospheric pollution, aggravated risks for utility workers, infrastructure corrosion, and odour nuisance. Field studies have shown that is difficult to effectively obtain reliable correlations between in-sewer air movement and gas pollutant concentrations. This study aimed at investi...

Mass transfer of a range of volatile substances was studied under highly turbulent conditions. The applied setup mimicked drop structures, where the release of volatile organic carbons likely occurs at a high rate. The experiments covered several substances in a range of resistances from residing entirely in the liquid film to being fully in the ga...

The application of the proposed approach in two districts of Maputo resulted in two different paths of evolution. In Magoanine B a more conventional approach seems to be adequate to its current low density characteristics and informally planned crosslinked structure. In Chamanculo D, the need for intervention is more urgent and is strongly blocked...

Abstract Production and build-up of sulfide in wastewater systems, especially downstream of rising mains, may lead to severe odour nuisance, toxic environments and high risk of corrosion. Due to increased population migration towards cities and lower area availability for treatment facilities, rising mains for the conveyance of wastewater sludge ar...

For engineering purposes it is especially useful to be able to predict and control sewer corrosion rates and odor impacts as well as to design effective measures aiming to reduce effects related to hydrogen sulfide formation and release. Doing so, it is important to use modeling tools that are capable of assessing variations of dissolved oxygen, di...

Na presente comunicação exemplifica-se o processo de implementação da ferramenta Hazur® na cidade de Lisboa, no âmbito do projeto RESCCUE, bem como se apresentam os principais resultados obtidos até à data. Pretende-se abordar o conceito de resiliência urbana de forma a fazer uma análise crítica ao estado de resiliência atual de serviços cruciais d...

The need for taking a comprehensive perspective when selecting sanitation technologies in developing contexts has been increasingly discussed. Process guides, which are planning documents describing steps decision-makers need to take, represent one possible contribution to attain comprehensive decisions. An interview study with sanitation experts w...

Climate change (CC) challenges require an integrated approach to increase cities’ resilience. Interactions of urban water systems with other urban systems and services are essential to city resilience. Risk identification related to CC for strategic urban services is an essential task for planning resilience in cities. Developments for Lisbon city...

The main objective of this paper is to develop a methodology for modelling dry and wet weather operational costs applied to the Alcântara Water Resource Recovery Facility (WRRF), which is the largest Portuguese WRRF. Following data collection and intensive data treatment and validation, dry weather patterns of WRRF performance were combined with sp...

Over the last decades, considerable progress has been made in the understanding of the sulfur cycle in sewer systems. In spite of a wealth of experimental and field studies that have addressed the release of hydrogen sulfide from free surface flows in gravity sewers and the corresponding air-water mass transfer, little is known about hydrogen sulfi...

The upgrading of sanitation systems in peri-urban slums, given the scarcity of resources is a challenging task. The paper presents the results of exploring the interdependence of urban infrastructures as a mean for identifying blocking situations. When unblocked a new step towards the modernization of sanitation systems has been taken and a new evo...

This paper presents the work carried out in a full-scale sludge rising main as to obtain insight into sulfide buildup and downstream H 2 S release. Obtained results allowed to assess formation rates and correlate them with operational procedures and inflow characteristics, thus contributing to a more efficient system management attaining risks (suc...

The paper presents a MCDA model designed to support the pre-selection of treatment alternatives for wastewater and feacal sludge in Mozambique. The model was tested using data from a specific site (city of Tete in the middle of the country) to demonstrate the usefulness of multi-criteria models specially at an early planning stage of the decision p...

Flow monitoring in wastewater systems is used for system operation or for billing purposes, among others. Given the difficult measurement conditions, gaps in measurement series occur frequently and stakeholders need an appropriate method to estimate missing data. In data scarcity situations, mathematical modelling of the underlying physical process...

Over the last decades, considerable progress has been made in the understanding of the sulfur cycle in sewer systems. In spite of a wealth of experimental and field studies that have addressed the release of hydrogen sulfide from free surface flows in gravity sewers and the corresponding air-water mass transfer, little is known about hydrogen sulfi...

The main objective of this paper is to demonstrate the importance of applying dynamic modelling and real energy prices on a full-scale water resource recovery facility (WRRF) for the evaluation of control strategies in terms of energy costs with aeration. The Activated Sludge Model 1 (ASM1) was coupled with real energy pricing and a power consumpti...

The presence and fate of hydrogen sulfide in wastewater systems were studied in two stretches of an intercepting sewer system located in a coastal village, in Portugal. A range of hydraulic parameters were obtained and liquid and gas phase measurements were carried out, both continuously and through intensive sampling campaigns. Upstream, where flo...

Hydrogen sulfide emissions from wastewater affect human health and equipment durability, thus presenting a complex issue for utilities. Several VOC emission models have been used before to predict H2S in collection systems and water resources recovery operations, even if with restrictions. By contrast, fewer studies focus on biosolids emissions and...

This study aimed at analysing the performance of horizontal subsurface flow constructed wetlands (CWs) to treat combined sewer overflow (CSO). Four horizontal subsurface flow CWs, organized in two groups (A and B) each with a planted (Phragmites australis) and a non-planted bed, were loaded with simulated CSO, with group B receiving twice the hydra...

This paper presents the findings of the assessment of sulfide formation in a 4.2 km long wastewater sludge rising main (in Costa do Estoril, Portugal) and downstream hydrogen sulfide release. Obtained results highlighted the differences between typical raw wastewater and wastewater sludge in terms of potential for sulfide build-up. Results also ind...

This study investigated the possibility of measuring yield coefficient values for the biomass of a laboratory-scale horizontal sub-surface flow constructed wetland (HSSF-CW) using a static respirometer. The respirometric tests used 300 mL bulk volume of biomass-laden gravel samples from the HSSF-CW, from which the biomass was detached by a vigorous...

Recent systematic studies on air-water flows have included stepped spillways. However, to date little has been investigated about how the hydraulic conditions on the stepped spillway may affect the design of traditional energy dissipation structures. In this paper, both smooth chute and stepped chute configurations terminating with the USBR type II...

Planning for urban sanitation in developing contexts is one of the major development challenges of this century. Particularly, the relevance of a broad perspective in sanitation decision-making processes has been increasingly discussed. One possible contribution to achieve comprehensive decisions is through the use of planning guidelines, also call...

Online monitoring programs based on spectroscopy have a high application potential for the detection of hazardous wastewater discharges in sewer systems. Wastewater hydraulics poses a challenge for in situ spectroscopy, especially when the system includes storm water connections leading to rapid changes in water depth, velocity, and in the water qu...

Managing combined sewage systems in large cities discharging to coastal waters, often bearing recreational activities, remains a challenge. Studying the impacts of such discharges requires the development of specific models. Hydrodynamic and water quality modelling of coastal waters employs numerical methods and algorithms, leading to the design of...

Over the past decades, treated wastewater (reclaimed water) has been used as an alternative to potable water for a range of uses such as irrigation (landscapes, golf courses, and agricultural fields), aquifer recharge, industry applications, stream flow feeding , and nonpotable urban applications. In that period, there have been significant advance...

Wastewater systems simulation models are receiving broader acceptance by utilities, and research interest in improving modeling techniques has gained awareness on the past decades, as decision support tools for system upgrading and asset management. In this paper, a joint use approach of 1D models and Computational Fluid Dynamics (3D models) is pre...

Climate change will likely lead to higher climate variability which must be addressed by increasing the robustness, flexibility and resilience of urban water cycle systems. Other anthropogenic pressures such as urbanisation, population growth and other landscapes and watershed changes add to climate related stresses. The urban hydrological cycle is...

Combined sewer systems are often unable to respond adequately to rising water volumes draining from urban areas during rainfall events, resulting in frequent direct discharges into receiving waters and floods, with severe environmental and economic impacts. Despite stricter legislation on pollution control and flood risk assessment, there are still...

Combined sewer systems are often unable to respond adequately to rising water volumes draining from urban areas during rainfall events, resulting in frequent direct discharges into receiving waters and floods, with severe environmental and economic impacts. Despite stricter legislation on pollution control and flood risk assessment, there are still...

Ultraviolet-visible (UV-Vis) spectroscopy is a promising tool for fast and simple evaluation of wastewater quality, as it delivers spectra that may be correlated to various aggregate wastewater quality parameters, such as Total Suspended Solids (TSS) and Chemical Oxygen Demand (COD). Its application in drainage systems has scarcely been reported an...

Operation, maintenance and rehabilitation comprise the main concerns of wastewater infrastructure asset management. Given the nature of the service provided by a wastewater system and the characteristics of the supporting infrastructure, technical issues are relevant to support asset management decisions. In particular, in densely urbanized areas s...

Wastewater drainage systems asset management decisions, in particular regarding rehabilitation interventions, are largely dependent on close-circuit television (CCTV) inspection results. However, the results of CCTV inspections are affected by several sources of uncertainty. Within the present communication, the inspector's uncertainty is quantifie...

Odor nuisance and sulfide corrosion in sewers carrying septic wastewater are accelerated at points of turbulence such as drops in manholes, but accurate methods or empirical expressions to evaluate the gas stripping rate at those particular sites are still missing. With the aim of improving the current knowledge on the influence of free-fall drops...

Using UV-Vis spectra and calibration transfer for wastewater quality monitoring in sewers

In longitudinal drainage systems, high discharges may occur suddenly due to short, intense rainfalls. These high discharges and related high flow velocities lead to high shear stresses near the bottom and can thus cause significant damages to the structure. It is well known that the installation of cross beams enhances the energy dissipation along...

The use of constructed wetlands as a valuable and attractive method for combined sewer overflow (CSO) treatment has been demonstrated in several studies. In Portugal, a Mediterranean country having usually a long dry period, there are still no applications of this technology. The purpose of this research is to gather information and know-how requir...

Climate change will likely lead to higher climate variability which must be addressed by increasing the robustness, flexibility and resilience of urban water cycle systems. Other anthropogenic pressures such as urbanisation, population growth and other landscapes and watershed changes add to climate related stresses. The urban hydrological cycle is...

No âmbito do projecto PREPARED – Enabling Change (7PQ), e do Projecto SIMAI – Sistemas de Monitorização e Aviso em infra-estruturas de drenagem urbana (FCT), está a ser desenvolvido um sistema piloto de alerta precoce de contaminação de águas com uso de recreio, aplicado à frente ribeirinha do estuário do Tejo. Este trabalho integra de forma explíc...

O alerta precoce de emergências e catástrofes (cheias, eventos graves de poluição, tsunamis) pode contribuir para a protecção do património e da vida humana em zonas costeiras e ribeirinhas. A previsão atempada destes eventos é essencial para a gestão do risco em comunidades vulneráveis, contribuindo para suportar decisões sobre a evacuação da popu...

Lead time between rainfall prediction results and flood prediction results obtained by hydraulic simulations is one of the crucial factors in the implementation of real-time flood forecasting systems. Therefore, hydraulic simulation times must be as short as possible, with sufficient spatial and temporal flood distribution modelling accuracy. One o...

Constructed wetlands are wastewater treatment technologies based in natural systems, and their environmental and hydraulic behaviour is influenced by weather conditions like temperature, solar radiation and precipitation. In this paper, a one-dimensional dynamic model applicable to horizontal flow constructed wetlands is presented. The structure of...

As alterações climáticas têm impactos significativos na distribuição temporal e espacial da disponibilidade dos recursos hídricos, na qualidade da água e no risco de ocorrência de cheias e secas. A estes impactos directos acrescem os efeitos indirectos resultantes de transformações das actividades económicas e sociais que agravam as pressões sobre...

As alterações climáticas têm impactos significativos na distribuição temporal e espacial da disponibilidade dos recursos hídricos, na qualidade da água e no risco de ocorrência de cheias e secas, a que acrescem efeitos indirectos resultantes de alterações das actividades económicas e sociais que podem agravar as pressões sobre o meio hídrico, desig...

O artigo apresenta um modelo hidrológico e hidráulico, desenvolvido sobre uma plataforma de informação geográfica, para avaliar o desempenho de uma rede de drenagem urbana pela aplicação do método racional generalizado. O modelo baseia-se numa rede conceptual constituída por bacias, troços de colectores e nós, e recorre a conceitos e operações de a...

In this paper, an overview on the development and application of state of the art integrated water modelling tools to study water pollution, either from urban or agricultural origin, from source to final destination, and also of the research carried out at IST in the framework of integrated water management is described. The modelling tools are use...

Urban sewer systems constitute a significant patrimony in Europe and worldwide. The structural quality and functional efficiency of sewer systems are fundamental to guarantee their good performance. These systems are nowadays facing problems of ageing, malfunctioning and overloading caused by deterioration due to long life times, improper maintenan...

A cidade de Lisboa enfrenta actualmente importantes desafios no que respeita a drenagem de águas residuais: parte considerável da rede encontra-se envel-hecida, o sistema recebe águas residuais dos concelhos vizinhos, os colectores são maioritariamente unitários ou comportam-se como tal, as marés do Tejo condicionam as descargas e afluem ao sistema...

No âmbito desta comunicação, desenvolvida pelos responsáveis pelo Plano Geral de Drenagem da Cidade de Lisboa, actualmente em elaboração para a Empresa Municipal de Águas Residuais de Lisboa (EMARLIS), apresenta-se o registo histórico da evolução de estudos e intervenções na cidade. Descrevem-se também as diversas fases de evolução do Plano Geral d...