Estimativa da infiltração e do afluxo devidos à precipitação na rede de esgoto sanitário em município de pequeno porte
Resumo
The main purpose of this work was to identify and to estimate the rainfall derived infiltration
and inflow (IADP) into the sewer in a small city and to do an analysis of their influence on
this collection system. This work was composed by field measurements on the sewage
flowrate output and volume arriving to the Sewage Pumping Plant Station, simultaneously to
the collection and measurement of rainfall on the corresponding same urban watershed area of
the Borborema, in São Paulo State.
The existing methodologies were divided in the follow steps: choosing and characterization of
the working field; data collection of the sewage volume and flowrate; collection of the rainfall
data; choosing and characterization of the data collected; employment of existing models and
methodologies useful to the present available data, in order to derive the underground water
infiltration rate and the overflow occurring in the sewage colletion network.
The volumetric and percentile IADP were quantified. The constant unitary rate (TUC) was
also estimated, by several ways. The results allowed obtaining mathematical formulations to
derive the IADP and TUC of the Borborema s sewage network. Such mathematical
formulations are suitable to be applied in urban areas of cities of a similar to that of
Borborema.
It was estimated that the IADP can generate flowrates 2,5 times greater than the sewage flows
in dry weather and infiltration rates in the sewage network similar to those adopted for system
design.
The work allowed to estimate how complex are the infiltration and inflow of stormwater in
the sewer network. The methodologies applied were quite simple and may be easily applied in
other cities.