Phosphorus dynamics in a highly polluted urban drainage channel-shallow reservoir system in the Brazilian semiarid.
An Acad Bras Cienc
; 91(3): e20180441, 2019 Aug 19.
Article
em En
| MEDLINE
| ID: mdl-31432901
This paper investigates phosphorus dynamics in a highly polluted system composed of a drainage channel followed by a shallow reservoir in the city of Fortaleza, Brazilian semiarid. During the dry season, significant non-point source loads of total phosphorus originated from residences unconnected to sewers were identified along the channel, resulting in an increasing flow rate of untreated sewage towards the reservoir. During the rainy season, as a consequence of dilution, phosphorus concentrations decreased by about 5-fold. The results also revealed that the reservoir was acting similarly to a waste stabilization pond, with phosphorus removal efficiency of about 33%. Assuming one-dimensional flow for the channel and complete mixing for the reservoir, it was possible to adjust phosphorus decay coefficients of kc = 2.2 day-1 and kr = 22.8 year-1, respectively, which were higher than their corresponding values available in the literature. This was attributed mainly to the relatively high temperatures and shallow water depths. The results also revealed an inverse dependence of kc and kr on water and wind velocity, with potential thresholds of respectively 0.3 and 5.0 m/s for resuspension of bed sediments and internal phosphorus loading.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
País/Região como assunto:
America do sul
/
Brasil
Idioma:
En
Revista:
An Acad Bras Cienc
Ano de publicação:
2019
Tipo de documento:
Article
País de publicação:
Brasil