Banca de DEFESA: LUARA PATRÍCIA LOPES MORAIS

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : LUARA PATRÍCIA LOPES MORAIS
DATA : 27/02/2026
HORA: 14:00
LOCAL: Sala de Aula do LASAP/UFERSA e Google Meet
TÍTULO:

EFFECTS OF LOW-FREQUENCY DYNAMIC ELECTRONIC PULSES ON CLOGGING OF DRIP EMITTERS OPERATING WITH SALWORKS BITTERN

PALAVRAS-CHAVES:

Descaling; Fouling; Emitters; Wastewater; Sustainability

PÁGINAS: 65
RESUMO:

Water scarcity and high climate variability in the semi-arid region have intensified the search for local inputs that reduce dependence on conventional fertilizers. In this context, the application of diluted solar salt production effluent via fertigation can integrate a circular economy strategy, enable nutrient recycling and mitigate the impacts of hypersaline effluent disposal. However, its adoption in drip irrigation systems remains conditioned by the risk of emitter clogging, since saline environments tend to favor salt precipitation, particle accumulation, and biofouling formation. Thus, this study evaluated the effect of reusing solar salt production effluent in drip fertigation, investigating whether the combination of dilution and ultra-low frequency dynamic electronic pulses can mitigate emitter clogging. To this end, three systems were installed in an experimental area of the Federal Rural University of the Semi-Arid Region, in Mossoró, Rio Grande do Norte, Brazil. The experiment was conducted in a completely randomized design, in a split-split-plot scheme, with three replications. The main plots corresponded to the water sources (dilution of effluent from a solar saltworks plus application of ultra-low frequency dynamic electronic pulses; only supply water; dilution of effluent from a solar saltworks without application of electronic pulses), while the subplots comprised the types of emitters (D1, D2 and D3). The sub-subplots represented the operating time, with nine levels (0, 40, 80, 120, 160, 200, 240, 280 and 320 h). The experimental setups were assembled using drip tapes with non-self-compensating emitters, operating at 80 kPa at the end of the lateral line. The physicochemical variability of the water sources over time was monitored, as were hydraulic performance indices, including the average rate of change of emitter flow and the Christiansen uniformity coefficient. Data on source quality and hydraulic performance were subjected to the Shapiro-Wilk normality test (p > 0.05). When the normality assumptions were met, the data were analyzed by analysis of variance (p ≤ 0.05), followed by Tukey's test (p ≤ 0.05). When normality was not met, comparisons were performed using the rank transformation procedure (RT-1), with Bonferroni's test (p ≤ 0.05). At the end of the experiment, samples from the clogged drippers were subjected to scanning electron microscopy and energy-dispersive X-ray spectroscopy. The results indicated that the application of electronic pulses did not promote changes in the chemical composition of the water sources; however, it was associated with a reduction in the total suspended solids content. The risk of clogging was mainly related to the interaction between alkaline pH, high electrical conductivity, and high concentrations of Ca²⁺ and Mg²⁺. Regardless of the treatment, the effluent dilutions from solar saltworks remained within a physicochemical range compatible with a high risk of obstruction, with a moderate risk associated with electrical conductivity and a severe risk related to pH and Mg²⁺. In contrast, the supply water presented the most favorable profile for controlling obstructions, with lower values of electrical conductivity, Ca²⁺, and Mg²⁺, and an absence of total suspended solids, although with a higher pH. The dilution of treated effluent showed a slight reduction in total suspended solids, indicating a lower particulate load and, consequently, less availability of surfaces for heterogeneous nucleation and biofilm-assisted deposition. From a statistical point of view, the dilution of untreated effluent compromised irrigation uniformity, while the dilution of treated effluent showed performance equivalent to that of the supply water. Although the hydraulic indicators remained high, the dilution of untreated effluent intensified the occurrence of transient clogging events, especially in the most sensitive emitter (D1), while emitter D3 showed the best overall performance. Regarding deposits, dilutions with effluents favored the formation of more mixed and complex incrustations, and electronic pulses reduced their complexity and modified the morphology, without, however, eliminating the obstruction, highlighting the dependence of the response on the hydraulic geometry of the emitter.

MEMBROS DA BANCA:
Presidente - 1753199 - RAFAEL OLIVEIRA BATISTA
Interno - 2578617 - STEFESON BEZERRA DE MELO
Externo ao Programa - ***.468.798-** - LUIZ FERNANDO DE SOUSA ANTUNES - UFRRJ
Externo à Instituição - GUSTAVO LOPES MUNIZ - Unicamp