Odour control: A successful experience in sorocaba city – Brazil

摘要

Public concern over odours from sewage treatment facilities have been increasingly significantly in Brazil inrnrecent years due to urban developments around existing plants or construction of new ones. The city of Sorocabarnis an example where the expansion of the sewage collection and treatment system has increased and consequentlyrnmore people have been exposed to bad odours. Due to this scenario, it was necessary to find arnsolution for this new challenge, but this is no easy task as people0s response to odours is subjective. In thisrncase, odours must be quantified first in order to be controlled. An electronic sensor (‘nose’) of H_2S (hydrogenrnsulfide) was installed at one selected pumping station and after one month of monitoring H_2S levels some chemicalrnproducts were tested in order to minimize bad odours. Best results were achieved using an iron salt blendrn(Fe_Ⅱ and Fe_Ⅲ) directly to the sewage flow at 30 mg/L (as Fe), which reduced by 83% the H_2S levels in the air.rnSuch reduction was adequate for mitigating odour complaints regarding that pumping station.