The main objective of the research was to study the effect of the Stenotaphrum secundatum and Zoysia japonica grasses on the higher and lower environment temperature and lower relative humidity; the secondary objective was to compare whether the Stenotaphrum secundatum grass has a greater impact on the environment parameters of comfort than the Zoysia japonica species. Six materials were used for the extensive green roof, each one forming a layer of the system, which were placed on the concrete slab and in an upward direction, including: PVC geomembrane, Polyester asphalt carpet, Pumice stone, Planar geodren, Prepared soil with guano, compost, muss, and Substrate. In order to make measurements of the higher and lower ambient temperature, a digital thermometer and lower relative humidity meter was used. Stenotaphrum secundatum and Zoysia japonica were used as grass species, as they were the most representative of the grasses used in extensive green roofs. The experimentation was carried out for 2 months from September to October of 2021, having built 3 modules of 1000x600mm roofs, including 1module of the concrete roof with ceramic covering and 2 modules of extensive green roof with two types of grass: Stenotaphrum secundatum and Zoysia japonica. The readings of the environment temperature and relative humidity of the higher and lower part were taken in six points of each module to have a greater number of representative measurements. The watering of the 2 green roof modules with grass was carried out twice a week, applying 5L of water per module. The results indicate that the Zoysia japonica grass is the one that presents a better behavior before the higher ambient temperature and that the Stenotaphrum secundatum grass behaves better before the lower ambient temperature and lower relative humidity. The conclusions indicate that the Stenotaphrum secundatum grass behaves better temperature and relative humidity; the two grass types exhibit different behavior.

Fundação de Amparo à Pesquisa do Estado do Amazonas / Green roofs have increasingly become an integral part of urban environments, mainly due to their aesthetic benefits, thermal comfort and efficiency in controlling excess runoff. However, the effects of this emerging technology in the qualitative characteristics of rainwater is still poorly understood. In this study, we evaluated the quality of rain water runoff from two extensive green roofs and a roof built with corrugated fiber cement sheets (control roof) installed in Santa Maria - RS. In addition, we analyzed the performance of both types of roof for controlling storm water runoff. For qualitative analysis of water, were determined physical (turbidity, apparent color, true color, electrical conductivity, total solids, dissolved solids, suspended solids and temperature), chemical (pH, phosphate, total nitrogen, nitrate, nitrite, chloride, sulfates, BOD, and hardness), metal (copper, iron, zinc, lead and chromium) and microbiological parameters (total coliforms and E. coli). Differences in rain water quality obtained at collection points were assessed using parametric test (Test t) and non-parametric tests (Mann-Whitney and Kruskal-Wallis test) with a significance level of 5% probability. The control of storm water runoff was analyzed from the runoff coefficient (C) and the water portion stored in both types of coverage. The results showed that, in general, GRs have not improved water quality, as indicated by some authors. On both green roofs occurred an increase of chloride, electrical conductivity, color, BOD, hardness, total coliforms, E. coli, phosphate, sulfate and turbidity. However, it was observed that GRs are able to convert the slightly acidic rainfall into basic water, which confirms its potential to neutralize acid deposition. Except for a few parameters, the quality of the collected water from the control roof did not differ significantly compared to GRs water. By comparing the results with the Brazilian environmental legislation, we noted that the runoff from all three roofs have potential for non-potable uses, such as floor and sidewalks washing, garden irrigation, toilet flushing, among others. About the performance of roofs in controlling storm water runoff, there was a significant efficiency of green roofs compared to the roof built with corrugated fiber cement sheets. This result was typified by the average values of flow coefficient, about 0.43 for GRs and 0.83 for control roof. However, the efficiency of green roofs controlling runoff proved to be very sensitive to weather conditions and antecedent soil moisture. To a future study about performance and interaction of various factors that could influence green roofs water quality and in its efficiency and controlling storm water runoff, we suggest long-term studies with different types of substrates, plant species and installation of the structures in locations with other types of occupation and environmental conditions, different from those verified in this work. / Os telhados verdes (TVs) têm cada vez mais se tornado parte integrante dos ambientes urbanos devido, principalmente, aos seus benefícios estéticos, conforto térmico e diminuição do escoamento superficial de águas pluviais. Contudo, os efeitos dessa emergente tecnologia nas características qualitativas de águas de chuva ainda é pouco compreendido. Neste trabalho foi avaliada a qualidade de águas de pluviais escoadas a partir de dois telhados verdes extensivos e de um telhado de fibrocimento (telhado controle) instalados em Santa Maria-RS. Complementarmente, analisou-se o desempenho de ambos os tipos de coberturas no controle quantitativo do escoamento pluvial. Para a caracterização qualitativa da água, foram determinados os parâmetros físicos (turbidez, cor aparente, cor verdadeira, condutividade elétrica, sólidos totais, sólidos dissolvidos, sólidos suspensos e temperatura), químicos (pH, fosfato, nitrogênio total, nitrato, nitrito, cloretos, sulfatos, DBO, e dureza), metais (cobre, ferro, zinco, chumbo e cromo) e microbiológicos (coliformes totais e E. coli). As diferenças na qualidade da água de chuva obtidas nos diferentes pontos de coleta foram avaliadas utilizando teste paramétrico (Test t) e testes não paramétricos (Mann-Whitney e Kruskal-Wallis), com um nível de significância de 5% de probabilidade. O controle do escoamento pluvial foi analisado a partir do coeficiente de escoamento (C) e da parcela de água armazenada nos dois tipos de coberturas. Os resultados apontaram que, em geral, os TVs não melhoraram a qualidade da água, como indicado por alguns autores. Ambos telhados verdes atuaram como fonte de cloretos, condutividade elétrica, cor, DBO, dureza total, coliformes totais, E. coli, fosfato, sulfato e turbidez. Contudo, observou- que os TVs foram capazes de converter o caráter ligeiramente ácido da água pluvial para básico, confirmando o seu potencial na neutralização de deposições ácidas. Com exceção de alguns parâmetros, a qualidade da água coletada do telhado controle não se diferiu significativamente em comparação às dos TVs. A partir da comparação dos resultados com as legislações ambientais consultadas, observou-se que as águas escoadas dos dois tipos de telhados apresentam características com potencial para usos não potáveis, tais como lavagem de pisos, calçadas, irrigação de jardins, descargas de bacias sanitárias, dentre outros. Com relação ao desempenho dos telhados no controle do escoamento pluvial, constatou-se uma significativa eficiência das coberturas verdes comparativamente ao telhado de fibrocimento. Esse resultado ficou tipificado pelos valores médios do coeficiente de escoamento, cerca de 0,43 para os TVs e de aproximadamente 0,83 para o telhado controle. Para melhor investigar a atuação e interação dos diversos fatores que podem influenciar na qualidade da água dos telhados verdes e também na sua eficiência quanto ao controle do escoamento pluvial, sugere-se estudos de longo prazo e com diferentes tipos de substratos, espécies vegetais e a instalação dessas estruturas em locais com diferentes tipos de ocupações e outras condicionantes ambientais distintas das verificadas neste trabalho.

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. / 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.