Odour characterisation of recycled HDPE in different washing and processing processes.

The waste of polymeric materials in our society is increasing year after year, generating a serious pollution problem. One way to deal with this waste problem is to recycle and reuse these materials. This process of recovery of used plastic materials aims to minimise their impact on the environment and reduce the energy consumption required for the generation of new consumer products. Recycling companies that recover these plastic materials must take into account some aspects such as transparency and colour, cleanliness, size, odour and sorting. One of the major disadvantages in accepting these recycled materials in the production processes is their odour, which in some cases causes the rejection of materials with comparable mechanical characteristics. High-density polyethylene, HDPE, is one of the polymeric wastes generated in the packaging industry. The aim of this work is to eliminate the bad odour of HDPE from waste collection plants for application in the recovery and reuse industry. HDPE supplied by a recycling company was washed, characterised and processed, and the odour was analysed by gas chromatography at each stage and by olfactory panel. In view of the results, it was observed that the washing processes managed to reduce the odour. Likewise, the processing of this waste by extrusion and injection managed to further reduce this effect, even eliminating some of the components responsible for odour by treating the samples with acetone and then extruding and injecting these samples. These results have a direct application in the packaging industry with significant shares of recycled material.

Actions to reduce carbon footprint in materials to healthcare buildings.

Building sector is a major contributor to the emissions of pollutant gases, which are responsible for health-damaging effects of climate change. To quantify and reduce these emissions. This comparative study is presented between two buildings that could have a sanitary or any other type of use. Both buildings have similar characteristics, except for their structures, one made of metal and the other of concrete. The design, structural calculation and three-dimensional dimensioning were performed using Building Information Modeling (BIM). The budget and the product carbon footprint study were also carried out, to calculate the level of emissions of each building. The study determined higher emissions for the metal-structured building, with 621.234 tCO2/tmaterial compared to 446.707 tCO2/tmaterial for the concrete building. To reduce these emissions, measures related to the replacement of the previously selected materials, by other materials with lower emission rates and identical functionality were presented, such as the replacement of metal building roof polyurethane, or the composition of cement for the concrete building. Both actions represented a reduction of 84.61% CO2 emissions for metal envelope building and 31.765% for the concrete structure. The results of this work will help to select more sustainable materials to use in the renovation of existing buildings, or in the construction of new buildings. For example, health-related buildings, currently in high demand, given the current pandemic situation caused by COVID-19.