Avaliação do desempenho de sistemas de tratamento de água em recirculação no descascamento e desmucilagem dos frutos do cafeeiro / Evaluation of the performance of systems in the treatment of water in recirculation for coffee bean hulling and mucilage removal

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

This work was carried out at the Coffee Bean Processing Sector of the Brauna Farm located in the municipality of Araponga, MG, to analyze the performance of a pressurized mesh screen for removal of solids and organic material combined with the traditional coffee bean processing via the wet method. The recirculation of water was operated in two ways: under short circuit, with the effluent from the processing machine being delivered to a 1.000 liter water tower, and then pumped up to a 3.000 liter water tower that fed the system, reinitiating the process; or, under long circuit , with the effluent from the processing machine being delivered to a 12.000 liter decantation tank, from where it was pumped up to a 3.000 liter water tower reinitiating the process. The pressurized mesh screen evaluated was installed after the processing machines used to treat the effluent which was alternately delivered to the 1.000 liter water tower and to the decantation tank. In both cases, the effluent was pumped to the 3.000 liter water tower used at the start of the water recirculation process. Electric conductivity (EC) and hydrogenionic potential (pH) were measured and the concentration of total solids (TS), suspended solids (SS), oxygen biochemical demand (BOD) and oxygen chemical demand (COD) were quantified in the samples collected. Based on the results obtained , it could be concluded that: a) When the system was operated under short circuit, a statistical difference (at a level of 10%) was observed in the affluent effluent concentration of TS, OBD and OCD in the pressurized screen. However, the screen showed low efficiency in removing EC (8%), TS (15%), SS (15%), BOD (26%) and COD (27%), with insufficient water qualitybeing provided for a 8-hour working day shift; b) when the system was operated under long circuit a statistical difference ( at a level of 10%) was observed in the affluent effluent concentration of SS, BOD and COD in the pressurized screen .However, the screen showed low efficiency in the removal of EC (8%), TS (14%), SS (18%), BOD (12%) and COD (23%). Thus, as observed in the short circuit, the screen did not present significant effects on recirculating water quality; c) The decantation tank was more efficient in the removal of EC (88%), TS (75%), SS (77%), BOD (66%) and COD (74%) from the recirculating water than the pressurized mesh screen.

ASSUNTO(S)

engenharia de agua e solo coffee processing processamento qualidade da água water quality filtration filtração café

ACESSO AO ARTIGO

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