CBL - Campus del Baix Llobregat

Projecte llegit

Títol: Eficiència de transformació residus a través de la utilització de Tenebrio mollitor

Estudiant que ha llegit aquest projecte:

Tutor/a o Cotutor/a: LOPEZ MARTINEZ, MARGARITA

Departament: DEAB

Títol: Eficiència de transformació residus a través de la utilització de Tenebrio mollitor

Data inici oferta: 01-02-2023      Data finalització oferta: 15-02-2023

Estudis d'assignació del projecte:
    GR ENG SIS BIOLÒG 23

Lloc de realització:
EEABB

Paraules clau:
Tenebrio mollitor, Residus orgànics, Residus inorgànics, Tractaments biològics, degradació biològica

Descripció del contingut i pla d'activitats:
Els tractaments biològics com el compostatge i la digestió
anaeròbia per a la transformació dels residus orgànics en
recursos útils per a diversos usos està àmpliament contrastada, i
la seva utilització molt estesa. En aquests processos intervenen
principalment microorganismes. Més recentment, altres processos
han incorporat la utilització de les larves d'insectes per a la
transformació de residus en diversos àmbits i per a l'obtenció de
productes de valor afegit. Aquest treball proposa estudiar
l'eficiència en la transformació de diferents residus orgànics
mitjançant la utilització de larves de Tenebrio mollitor.
El pla d'activitats consisteix en seleccionar diversos residus i
processar-los mitjançant les larves per valorar l'eficiència del
procés.

Overview (resum en anglès): The recent need to develop new ways to reduce waste without harming the environment has made the species Tenebrio molitor popular. Although its ability to degrade different types of waste, including plastic, is known, the following question arises: Is this species only capable of degrading plastic waste? Is it effective with other waste?
Thus, the main objective was to evaluate the degradation of different wastes (horse feces, organic fraction, textile waste, compostable plastic and cardboard, polystyrene tray, coffee grounds and oat flakes) by the action of Tenebrio molitor larvae at controlled temperature 25 °C, inside 1L glass jars, between 4 and 6 weeks, and to evaluate the survival, pupation, excrement generation and transformation of the exposed wastes. In the first test, survival and pupation were evaluated for 4 weeks with textile waste, oat flakes, organic fraction, fruit skins and coffee grounds. The organic fraction did not present adequate conditions, had high mortality and did not develop pupae, while the fruit skins presented high survival at the end of the test (75%) and the textile waste and compostable cardboard, although with low survival (14% and 31% respectively) also pupated (7% and 11%). The addition of oat flakes to textile waste promoted survival and pupation. Excess moisture in the organic fraction generated fungi. The results obtained served as a basis for developing the other tests, where in addition to determining survival and pupation, the generation of excrement and non-degraded final waste was also quantified. The second test, carried out with compostable plastic, polystyrene with oat flakes, organic fraction, organic fraction with oat flakes and horse feces, introduced more waste than in the first test and lasted for 6 weeks. The survival rate was between 30% and 66%, but pupation, with a maximum value of 66% in the organic fraction with oat flakes, was notably lower in the compostable plastic, with a value of 5%. In the third test, carried out on textile waste, compostable cardboard, organic fraction and horse feces, more larvae were laid and lasted 6 weeks. Survival did not show major differences, with values below 30% and 8% in the organic fraction. Pupation remained between 7% and 20%. The generation of excrement per gram of larvae was higher in the second test, especially for the compostable plastic (130 mg per gram of larvae) and the organic fraction (250 mg per gram of larvae).
Two of the most important conclusions that were obtained is that some wastes, such as coffee grounds, or at least in the conditions in which the test was done, were not suitable for Tenebrio, and on the contrary, textile waste and compostable cardboard, materials that can be considered of low degradability, showed good survival and pupation results, thus opening a possible management avenue for these wastes. It has also been observed that the presence of oat flakes enhances survival and pupation when placed with other materials. It should also be noted that there was a certain dispersion of data between replicates, so that in future experiments it would be necessary to establish conditions to reduce this impact.


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