DSpace Coleção:
https://rd.uffs.edu.br/handle/prefix/5756
2024-03-28T17:48:30ZInfluência do modo de alimentação sobre o desempenho de wetland construído vertical de fundo saturado no tratamento de esgoto sanitário
https://rd.uffs.edu.br/handle/prefix/5772
Título: Influência do modo de alimentação sobre o desempenho de wetland construído vertical de fundo saturado no tratamento de esgoto sanitário
Autor(es): Bassani, Leandro
Primeiro Orientador: Sezerino, Pablo Heleno
Abstract/Resumen: The vertical flow constructed wetlands (VFCW) are considered consolidated systems
worldwide in wastewater treatment, presenting stability in the quality of the treated effluent and
low constructive and operational requirements in relation to compact systems with induced
energy, making them an attractive ecotechnology to decentralized systems. Design and
operation criteria have been established under different contour conditions. However,
understanding of the influence of the feeding mode (FM) of influent on the efficiency of
wetlands is not fully established in the technical literature, being scarce and discrepant the
available information regarding the optimized operation of the VFCW and of the partially
saturated vertical flow constructed wetlands (PVFCW) modality. This difficulty in fixing the
optimal FM is linked to the complexity of the mathematical description of the pollutant
transformation kinetics when transmitted to transient flow in a porous medium, as occurs in
both wetlands. In this way, this study aimed to optimize the performance of sanitary wastewater
treatment promoted by PVFCW, through the variation of the specific volume (SV) applied in
an influent pulse and the specific hydraulic rate (SHR), as well as, to compare the treatment
performance promoted by VFCW and PVFCW, when both were submitted to the same
operational condition. The results obtained for the PVFCW regarding the decrease in SV from
25.35 L m -2 to 12.29 L m -2 did not show a statistically significant impact on the efficiency of
removal of influent loads of COD, BOD 5 , NT and N-NH 4 + . For the COD load removal
efficiency parameter, the median efficiencies were 95.5% and 94.2% for the SV of 25.35 L
m -2 and 12.29 L m -2 , respectively. For the TN parameter, the respective median load removal
efficiencies were 49.11% and 56.2% for the highest and lowest SV, respectively. For the NH 4 +-
- N parameter, the mean load removal efficiencies were 79.5% and 76.9%, respectively. Finally,
for the PO 4 3- -P parameter load removal efficiency, statistically significant differences were
observed, with median efficiencies of 82.2% and 91.3% for the highest and lowest SV
respectively. Moreover, no significant differences were detected for the means of maximum
oxygen consumption rate (OCR max), when the SV value was varied (46.03 g O 2 m -2 d -1 for
SV of 25.35 L m -² and 44.36 g O 2 m -2 d -1 for SV of 12.29 L m -² ). The SV variation also did not
result in statistically significant differences in the ratio between the power consumed by the
pumping system and the mass of oxygen introduced. In median terms, the values obtained for
this criterion were 0.148 KW Kg O 2 -1 and 0.145 KW Kg O 2 -1 for the highest and lowest SV,
respectively. Regarding the SHR from 4 to 9.6 L m -2 min -1 , concomitantly with a reduction of
hydraulic loading (HL) from 101.4 to 74.9 mm d -1 , there was also no improvement in the charge
removal efficiency of the evaluated physicochemical parameters. However, energy efficiency
was lower for operation with an SHR of 9.6 L m -2 min -1 compared to 4 L m -2 min -1 (7.84 kg O 2
kW h -1 for the largest SHR to 19.29 kg O 2 kW h -1 for the smallest SHR). Considering that the
BOD 5 and NH 4 + -N effluent concentrations were below the legal limit of discharge of treated
wastewater for the two SHR values, it is concluded that an SHR of 4 L m -2 min -1 is sufficient
to comply with environmental legislation concomitantly with lower energy consumption. In
relation to the comparison between VFCW and PVFCW, the results show the superiority of the
PVFCW in the load removal efficiency for all quality parameters evaluated. Considering the
results obtained, it is concluded that the best configuration for VFCW for advanced secondary
treatment of sanitary wastewater is the PVFCW typology, operated with HL varying between
75 and 100 mm d -1 , the minimum SHR of 4 L m -2 min -1 , SH between 12 and 25 L m -2 and
minimum interval time between pulses of 3 hours.
Instituição: Universidade Federal de Santa Catarina
Tipo: Tese2020-07-21T00:00:00Z