Papers

Wastewater treatment plants (WWTPs) are facing challenges concerning the service

The present paper aims at proposing and demonstrating the application of a decision-making approach that allows the identification, assessment, comparison and prioritisation of different intervention solutions. Infrastructural, financial, performance and economic perspectives are taking into consideration in the study. The proposed approach is composed of three main modules: 1) Analysis planning and database construction; 2) Infrastructure, asset or component diagnosis and prioritisation; and 3) Study of intervention solutions for the assets or components priority for intervention. Three assessment levels

In Southern European countries, due to the specific climate, economy and culture, a permanent heating practice during winter is not widely adopted. This may have a significant effect on the performance of indoor coating materials, typically tested considering hygrothermal conditions in the range of 33

In Southern European countries, due to the specific climate, economy and culture, a permanent heating practice during winter is not widely adopted. This may have a significant effect on the performance of indoor coating materials, typically tested considering hygrothermal conditions in the range of 33

This paper aims at proposing and demonstrating the application of a novel distress-based condition assessment approach to evaluate the physical condition of inspectable urban water assets based on the classification of anomalies in terms of severity, intensity and extension using three new deterioration indices. These indices are, firstly, calculated at the asset component level and, then, aggregated at the asset level and at the infrastructure level by weighing the component indices with the respective replacement cost or criticality. A condition grading classification associated with the deterioration indices is proposed. The novel distress-based condition assessment approach is applied to 22 drinking water storage tanks and 17 wastewater pumping stations located in Portugal, that have been specifically inspected for this purpose. Results of deterioration indices are compared with those obtained by the value-based condition assessment approach. Results demonstrate that the proposed approach allows a more reliable assessment of the assets

Circular/spherical rigid particle models that were initially applied to rock fracture studieswere not able to match the ratio of the compressive strength to tensile strength that occurs in rock.In addition, the predicted macroscopic friction angle was much lower than the known hard rockexperimental values. Several enhancements have been proposed to address these issues, namelythe use of a clumped particle logic or the adoption of polygonal/polyhedral grain structures, eitherrigid or flexible. In this work, a flexible 2D DEM based particle model (PM) that allows deformableparticles to interact in a simplified way is presented. The proposed flexible PM model keeps thecontact interaction simplicity and the reduced computational costs characteristic of circular rigidparticle models. The PM model is tested using biaxial tests and Brazilian tests. A discussion re-garding the influence of the grain deformability on the macroscopic elastic and strength response ispresented. It is shown that, when compared with a rigid model, the proposed flexible PM modelpredicts more reasonable indirect tensile strength to direct tensile strength ratio and requires asmaller value of contact fracture energy to give a good agreement with known experimental data.It is also shown that the proposed flexible PM model can predict a behaviour similar to that ob-tained using a flexible PM model through inner particle discretization that is more computationallydemanding.

Circular and spherical particle models are a class of discrete elements (DEM) that have been in-creasingly applied to fracture studies of quasi-brittle materials, such as rock and concrete, due to their proven ability to simulate fracture processes through random particle assemblies repre-senting quasi-brittle materials at the grain scale. More recently, DEM models have been applied to old stone masonry fracture studies. In order to extend its applicability to structures of larger di-mensions, an enhanced hybrid particle model is here proposed that allows finite elements with a given surface roughness, provided by the discretization of the element boundary with particles, to interact with the particulate media in which they are embedded. The performance of the hybrid model is compared with that of a traditional all-particle model under uniaxial testing. It is shown that similar results are obtained, namely in the elastic phase, figures of rupture, pre-peak and post-peak behaviour, while the hybrid model allows a significant computational run time re-duction of 20% to 25% in the coarse particle assemblies. Finally, the proposed hybrid model is applied in the simulation of shear tests of stone masonry walls, dry and mortared joints, providing a reasonably good agreement with both experimental results and predictions. For the rubble masonry tests, the hybrid model allows a computation run time reduction of around 40%, when compared with an all-particle model.

The efficient planning of operation and maintenance (O&M) interventions and short-term investments requires adequate and tailored inspection protocols of existing infrastructures. The current study proposes a new standardized inspection system for periodic visual surveys of storage tanks and pumping stations of urban water infrastructures. The proposed system aims at identifying and classifying anomalies in terms of severity, intensity, and extension to evaluate the asset and its components deterioration. Inspection forms specific for water storage tanks and pumping stations are proposed. A set of 22 water storage tanks and 17 wastewater pumping stations located in Portugal were inspected using the developed system. Several anomalies

This paper presents a novel energy balance scheme tailored for assessing energy efficiency in wastewater systems. It provides a consistent method to calculate the energy components associated with wastewater transport processes, allowing the quantification of the main water-energy inefficiencies. Three assessment levels are described (macro, meso and micro-level), depending on available information and scope. This balance allows a holistic approach of wastewater systems energy efficiency, including the system layout, losses in pipes/manholes, energy associated with undue inflows, exceedance volumes and energy recovery. The energy balance is applied to realcase studies. The energy associated with undue inflows represents from 20% to 44% of the external energy, with low average efficiencies of wastewater pumping systems (34%) and inflow intrinsic energy representing 64% of the total energy. This energy balance supports the performance diagnosis and the development of energy efficiency improvement measures.

This study aims proposing a novel geometry of the onshore Oscillating Water Column (OWC) device to increase its efficiency. A comparison between standard OWC