Grazielle Pessoa do Império Borges

Abstract:

Polyhydroxyalkanoates (PHA) are polyesters produced by bacteria. Furthermore, they are fully biodegradable, representing a rapid degradation response. Bacteria can accumulate PHA from sewage sludge, as there is a significant percentage of carbon-based materials in this waste; such as cellulose, PHA, lipids and fatty acids.

With the evolution of studies related to PHA, it is possible to improve its production method. In this way, the polymer will be a very good alternative for the production of bioplastic, as in addition to being a biobased product, it is also biodegradable.

The sewage sludge is a product from the waste water treatment plants. The treatment of this product is required to lessen the impact of wastewater disposal. This process requires a certain amount of energy that could be saved with sustainable technologies. As an option, sewage sludge can be used as a raw material for other activities. As is the case with PHA production, sewage sludge is very useful as it contains carbon-based materials, which will serve as a medium for the production of bacteria.

This project is a life cycle analysis of two PHA production paths that use sewage sludge as raw material. The first production mode uses a Dimethyl carbonate (DMC) solvent to extract the polymer from the bacteria, after which the sludge undergoes an enrichment and accumulation process. The second mode of production skips this process, making a compounder of the polymer with the biomass.

To compare the two routes, an analysis was made of the resources used, such as energy, water and, in the case of the first route mentioned, the use of solvent. The amounts were applied in the Gabi software. Gabi is an abbreviation of the German word Ganzheitliche Bilanzierung, which literally translated means holistic accounting. GaBi is a software used to facilitate the creation of a lifecycle analysis plan. Using this platform, it is possible to understand the carbon footprint of a product, optimize the process and, in the case of a company, gain market share

It is concluded that the process of direct extrusion, having as output a compounder rich in biomass. is the most sustainable option for PHA production.