Banca de DEFESA: JOÃO CARLOS PINTO DE LIMA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : JOÃO CARLOS PINTO DE LIMA
DATE: 29/10/2025
TIME: 14:00
LOCAL: Sala do PGEAAmb
TITLE:

ADDITION OF LITHOTHAMNIUM TO THE SOIL OF CONSTRUCTED WETLANDS TREATING CATTLE FARMING WASTEWATER: INFLUENCE ON NUTRIENT REMOVAL

KEY WORDS:

constructed wetlands; Lithothamnium calcareum; Chrysopogon zizanioides; wastewater treatment; dairy cattle farming; nutrient removal.

PAGES: 133
BIG AREA: Ciências Agrárias
AREA: Engenharia Agrícola
SUMMARY:

Dairy cattle farming generates large volumes of wastewater with high organic and nutrient loads, representing an environmental challenge when discharged without adequate treatment. Vertical Flow Constructed Wetlands (VFCWs) are a sustainable alternative for treating these effluents but require optimization to maximize pollutant removal efficiency. This study evaluated the effect of different proportions of Lithothamnium calcareum (0%, 10%, 20%, and 30%) and the presence of vetiver grass (Chrysopogon zizanioides) on the removal efficiency of organic matter, nutrients, and physical parameters in VFCWs treating dairy wastewater. The experiment followed a randomized block design with a 4×2 factorial arrangement, totaling eight treatments with two replicates and eight sampling dates over two months (n=128 observations per parameter). The influent wastewater showed average concentrations of 3,383.1 mg/L COD, 89.4 mg/L ammoniacal nitrogen, 56.6 mg/L nitrate, 4.6 mg/L nitrite, 353.3 mg/L phosphate, 26,075 PtCo color, and 1,337.4 NTU turbidity. The results demonstrated that Lithothamnium calcareum had a statistically significant effect on the removal of COD (p = 0.004), color (p = 0.009), and turbidity (p = 0.003), with efficiencies ranging from 76.7% to 81.3% for COD, 74.9% to 96.6% for color, and 74.3% to 98.9% for turbidity. The LC 30% CV treatment showed the best performance for COD (81.3%) and turbidity (98.9%). The presence of Vetiver had a significant effect on ammoniacal nitrogen (p = 0.009) and nitrate (p = 0.013), with N-NH₄⁺ removal efficiencies ranging from 94.4% to 100.0%. Notably, the control treatment (LC 0% CV) showed higher efficiency for nitrate (84.4%), indicating negative interference of LC on denitrification processes. For nitrite and phosphate, no significant effects of the tested factors were detected, although the efficiencies were satisfactory (71.0-76.9% for NO₂⁻; 86.1-88.4% for PO₄³⁻). Chlorophyll assessment revealed a non-linear pattern with a minimum at LC 20%, suggesting possible competition for phosphorus between the plant and the substrate. It is concluded that Lithothamnium calcareum is a promising component for VFCWs aiming at the removal of organic matter and physical parameters, while Vetiver contributes to the transformation of nitrogen compounds, providing support for the optimization of agro-industrial wastewater treatment systems.

 

COMMITTEE MEMBERS:
Presidente - 1759225 - ALEXANDRE LIOI NASCENTES
Interno - 2353141 - LEONARDO DUARTE BATISTA DA SILVA
Externo à Instituição - Jaime Lopes da Mota Oliveira - FIOCRUZ