Étude des performances environnementales et énergétiques des toitures végétalisées et évaluation de leur impact en termes de gestion de l'eau de pluie

Vegetative roofs (VRs) can be classified into two types : Extensive (EGR) and Intensive (IGR). The main differences between the two are the type of vegetation, the depth of the substrate. This research aims to achieve the following objectives : 1. Determine and compare the potential environmental impacts of traditional gravel ballasted roofs (TGBRs), white reflective roofs (WRRs), EGRs, and IGRs ; 2. Evaluate and compare the energy performance and the heating/cooling demand of TGBRs and EGRs ; 3. Determine and compare the water management potential and the runoff dynamics of TGBRs and EGRs. The first objective was covered by performing a comparative Life Cycle Assessment (LCA) on a real EGR of 834m2 and on three fictitious roofs of the sane area : of TGBRs, WRRs, and IGRs. Results indicated that the EGR had the least potential environmental impacts for the 15 impact categories considered. The second and third objectives were achieved by first installing one TGBR mockup and two EGR mockups on the rooftop of the Chemical Engineering Department at the University of Balamand, Lebanon. EGR8 and EGR16 are EGR mockups differed in the roof slope, the depth and the composition of their substrate. Temperature profiles at different substrate depths clearly indicated the reduction of the temperature fluctuations under the substrate layer, the heat storage effect, and the passive cooling effect. The economic study showed that EGR could save up to 45USD/200m2/month compared to TGBR. The water management performance of EGRs illustrated that the soil composition of EGR8 was more efficient than that of EGR16. In contrast, EGR acted as a sink especially for cadmium, iron, calcium, and ammonium.Les toitures végétalisées (TTV) existent en deux types : extensive (EGR) et intensive (IGR). Ils diffèrent principalement par le type de végétation et la profondeur du substrat. Ces travaux de recherche visent à atteindre les objectifs suivants : 1. Déterminer et comparer les impacts environnementaux d’un toit de gravier ballasté traditionnel (TGBR), d’une toiture réfléchissante (WRR), EGR, et IGR ; 2. Quantifier la performance énergétique d’un TGBR et d’une EGR ; 3. Évaluer le potentiel de gestion d’eau et la dynamique de ruissellement d’un TGBR et d’une EGR. Le 1er objectif a été atteint suite à une Analyse comparative de Cycle de Vie (ACV) d’une EGR réelle de 834 m2 et de trois toits fictifs : TGBR, WRR, et IGR. Les résultats indiquent qu’une EGR présente les impacts environnementaux les plus bas pour les 15 catégories d'impacts considérées. Les aspects thermiques et hydriques des TTV ont été testés suite à l’installation d'une maquette TGBR et de deux maquettes EGR sur le toit du département de génie chimique à l'Université de Balamand, Liban. EGR8 et EGR16 sont des maquettes EGR qui diffèrent par la pente ainsi que la profondeur et la composition du substrat. Les profils de température indiquent la réduction des fluctuations de température, l'effet de stockage de chaleur, et l'effet de refroidissement passif. L'étude économique montre que EGR pourrait économiser jusqu'à 45USD/200m2/mois par rapport à TGBR. D’autre part, les profils de la teneur en eau ont démontré que la composition du sol d’EGR8 est plus efficace que celle d’EGR16. En revanche, EGR agit comme un système filtrant surtout pour le cadmium, le fer, le calcium et l'ammonium

Real-time temperature monitoring for Traditional gravel ballasted and Extensive green roofs: A Lebanese case study

International audienc

Alternative stabilisation method for unfired earth blocks

Clayey soils have been used in the construction of buildings since ancient times. It reduces the building’s ecological footprint while improving thermal comfort. Soil is a local material that helps people in temperate regions cope with harsh environmental conditions such as high temperatures. The performance of such materials is determined by the soil’s chemical composition and physical properties. The main issue with these materials is their high shrink sensitivity and tendency to crack during drying. These pathologies can result in fundamental mechanical performance degradation. The purpose of this work is to investigate various scenarios for the stabilization of compacted soil blocks.In this context, this research investigates the use of alternatives to cement for the stabilization of earth blocks. Sample blocks were constructed using varying concentrations of stabilization materials. The samples’ mechanical strengths were assessed. Simultaneously, materials will be compared in terms of ease of manufacture, and financial cost. The mechanical properties (compressive and flexural strength) of stabilized earth blocks shows that the developed mix outperforms the traditional masonry concrete block. The results of this study show that stabilized earth blocks are gaining their place as a viable, sustainable, affordable building material suitable for low-cost housing construction

Use of aluminum powder for the development of a sustainable paste used in the restoration of historical monuments

The preservation of historic sites requires the development of sustainable restoration materials.. This work examined the use of aluminum powder as a main component in the manufacturing of environmentally friendly pastes for historical monument repair. These pastes currently present a sustainable remedy by inserting the aluminum powder having special properties such as its light weight and size, resistance to corrosion, and excellent thermal conductivity [1]. By thoroughly examining the mechanical, aesthetic, and sustainability aspects of these materials, this study provides insights into the effectiveness and long-term preservation advantages of aluminum powder-based pastes. Results highlighted that the produced pastes have remarkable mechanical properties, such as high compressive strength, superb adhesion, and dimensional stability. Additionally, they are aesthetically compatible, making it possible to replicate the materials and surface textures of the originals. Aluminum powder-based pastes reduce waste and the carbon footprint of restoration projects from a sustainability standpoint. Case studies that successfully use these pastes in the restoration of historical monuments are included in the publication, showing their efficacy, tenacity, and aesthetic compatibility [1]. All things considered, the incorporation of aluminum powder in environmentally responsible pastes reveals to be a promising development in the preservation and restoration of historical monuments, assuring their preservation for future generations while keeping environmental responsibility

Cradle-to-gate Life Cycle Assessment of traditional gravel ballasted, white reflective, and vegetative roofs: A Lebanese case study

International audienc

Aspen Plus designing and optimizing the hospital wastewater treatment by wet air oxidation method

Healthcare establishments, pharma industries, and medical laboratories generate various waste materials, collectively called hospital or healthcare waste. Waste management regulations differ depending on the laws and acts adopted by the authorities and their level of compliance. For instance, in the United States of America, hospitals follow the rules set by the Environmental Protection Agency. In Europe, hospitals adhere to guidelines and standards set by the European Environmental Agency, while globally, the World Health Organization has established standardized policies and regulations. As a result, waste treatment technologies have become more prevalent for making medical waste non-infectious. These treatments include thermal treatment using microwave technologies (e.g., Wet air oxidation), steam sterilization, electro-pyrolysis, and chemical and mechanical systems. This research aims to model the treatment of hospital wastewater by wet air oxidation method using Aspen Plus for the first time in Lebanon. The simulation showed that the reaction conversion yield for thiols or mercaptans was 89.7% and 83.8% for sodium hydrosulfide, and the COD and BOD5 levels were reduced by 79.1% and 88%, respectively