Banca de DEFESA: ANDRESSA BLASI PAIVA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : ANDRESSA BLASI PAIVA
DATE: 20/02/2026
TIME: 10:00
LOCAL: On line
TITLE:

Potential of using microalgae-based biofertilizer for fertigation based on the obstruction of different types of drippers

KEY WORDS:

Zea mays L. Biostimulants. Biological treatment. Circular economy. Effluent reuse.

PAGES: 68
BIG AREA: Ciências Agrárias
AREA: Engenharia Agrícola
SUBÁREA: Engenharia de Água e Solo
SPECIALTY: Irrigação e Drenagem
SUMMARY:

Population growth demands that the agricultural sector produce ever-increasing amounts of food. This high demand results in greater use of fertilizers and pesticides to maintain and increase productivity in the field. Currently, more sustainable alternatives are emerging, such as the use of biofertilizers and biopesticides. However, these industries also generate effluents. Biological treatment using microalgae can be a solution for these wastewaters, reducing pollutants and allowing the reuse of waste as agricultural bio-inputs. Thus, the objective of this study was to evaluate, in the first chapter, the bioremediation of wastewater from the biopesticide and biofertilizer industry (ARBB) using a microalgae mix containing Chlorella sp., Spirogyra sp., and Nostoc sp., in addition to performing the physicochemical characterization of the resulting solutions and quantifying the presence of phytohormones and their influence on the germination of corn seeds (Zea mays L.). The concentrations of pollutants such as total nitrogen (TN), Chemical Oxygen Demand (COD), and Phosphorus (P) were quantified in the raw effluent and after microalgae cultivation. Three solutions were prepared for the germination test: S1 (ARBB + microalgae), without alteration in composition; S2, ARBB + microalgae solution concentrated by removing 50% of the liquid phase using ferric chloride; and S3, containing only the liquid phase removed from S2. The presence of phytohormones was evaluated in all three solutions. The germination test was carried out in a BOD chamber for 7 days, comparing the treatments containing solutions S1, S2, and S3, gibberellic acid, and the control (distilled water). The experimental design was completely randomized (CRD). In the second chapter, the objective was to produce biofertilizers based on microalgae cultivated in ARBB, their physicochemical characterization, and the application of the biomass in pots to evaluate the initial development of corn. The physicochemical characterization analyzed the same parameters as in Chapter 1. For nutrient concentration, the microalgae biomass was centrifuged. Two cultivations were carried out, both lasting 30 days. The treatments analyzed were: T1 (water – control), T2 (100% urea), T3 (80% urea and 20% biofertilizer), T4 (60% urea and 40% biofertilizer), and T5 (100% biofertilizer), in a completely randomized design (CRD). Good pollutant removal efficiency was observed after treatment with microalgae, mainly for total nitrogen (TN), nonitrogen (NA), and chemical oxygen demand (COD), with efficiencies above 98%. The hormones detected in the microalgae solutions were Gibberellin, Cytokinin, Auxin, and Abscisic acid, mainly in solutions S1 and S2. There was no interference from the analyzed treatments in the percentage and speed of germination. Gibberellic acid showed the best results for seedling height, with a significant difference compared to the other treatments. The treatments with microalgae showed statistically higher height values compared to the control. For fresh and dry weight of the aerial part of the seedlings, the highest results were obtained with gibberellic acid and solution S1, being equal to each other and differing statistically from the others. For root length, dry and fresh weight, there was no significant difference between the treatments. The presence of essential macronutrients for plants was observed in the biofertilizer produced with ARBB + microalgae, mainly N and P. In the two cultivations carried out, there was no statistical difference between the treatments for the morphological parameters analyzed, namely plant height, stem diameter, number of leaves, leaf area, and fresh and dry weight of the aerial part. Although no statistical difference was observed, it is noted that, in general, the lowest values of the morphological parameters were found in the control treatment. The study of the agronomic potential of bio-inputs produced with microalgae is relevant, considering their activity as a biostimulant and biofertilizer, and the potential for the disposal of agro-industrial waste.

COMMITTEE MEMBERS:
Interno - 2131822 - CONAN AYADE SALVADOR
Interno - 1133133 - HENRIQUE VIEIRA DE MENDONCA
Externo à Instituição - CICERO CELIO DE FIGUEIREDO - UnB