Biobased additives as biodegradability enhancers with application in TPU-based footwear components

Among the wide variety of materials employed in the manufacture of shoes, thermoplastic polyurethanes (TPUs) are one of the most widely used. Given its widespread use, and associated waste management problems, the development of more biodegradable and evironmentally compatible solutions is needed. In this work, a polyester-based TPU used in the footwear industry for outsoles production was modified by compounding with lignin, starch and cellulose at content of 4% (w/w). The biodegradability was evaluated by using agar plate tests with the fungi Aspergillus niger ATCC16404, the Gram-negative bacteria Pseudomonas aeruginosa ATCC9027 and an association of both (consortium), and soil tests at 37 °C and 58 °C. The obtained results evidenced a positive effect of the tested biobased additives, the most favourable results being registered with lignin. These results were corroborated by the structural modifications observed by FTIR analysis. Additionally, mechanical tests prove the suitability of using the lignin modified TPUs for footwear outsoles production.

Characterization of residual soil used for infiltration of reclaimed water

The effects of climate change and the growing demand for water for domestic, industrial, agricultural and recreational activities have been led the use of treated wastewater (reclaimed water) for such applications. The artificial recharge of aquifers with treated wastewater can be an alternative way for restoring underground water volumes that can be used for satisfying some activities, particularly in water shortage areas or where their quality is not suitable for use. After a two-year monitoring period in the Vila Fernando WWTP (Guarda, Portugal), the characteristics of the treated effluent suggest that it could be used for infiltration for aquifer recharge. A multi-criteria analysis based on GIS was developed for site location of infiltration sites. The procedure has involved the combination of six thematic maps and environmental, technical and economic criteria, over an area of 6687.1 ha. About 6.4 ha were selected for suitable sites for infiltration and one of these sites (Quinta de Gonçalo Martins, Guarda) was selected for collecting soil samples. The characterization of the soil indicates that is favorable to the infiltration of treated wastewater for artificial recharge of aquifers.