Sistema combinado aplicado ao tratamento de esgoto sanitario contendo formaldeido : desempenho e avaliação biomassa / Domestic wastewater treatment containing formaldepyhe byan anaerobic filter followed by a biological aerated filter : performance and biomass valuation

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

30/08/2007

RESUMO

This study was developed with the intent to verify the treatability of domestic wastewater containing formaldehyde in a combined system formed by an Anaerobic Filter followed by a Biological Aerated Filter, each one with 12 h of hydraulic retention time (HRT). The reactor s performance was monitored by different influent formaldehyde concentration applied in the influent domestic wastewater, ranging from 57 ± 59, 90 ± 55, 267 ± 53, 420 ± 137, 533 ± 174 until 946 ± 131 mg/L, considering that the raising concentration was given after the wastewater treatment stabilization in each stage. The maximum formaldehyde rate applied in the combined system achieved 1,121 kg HCHO/m3.d and the maximum removed was 1,116 kg HCHO/ m3. d. During this stage there was also the maximum applied and removed COD loading rate, represented respectively by 2,5 kg COD/m3.d and 2,2 kg COD/m3.d. The maximum removed formaldehyde and COD rate were not reached. The removal average of the formaldehyde concentration in the combined system was 94 ± 2 %, and the average formaldehyde concentration in combined system effluent was 5 ± 2,4 mg/L. However, the average COD concentration reduction was 84 ± 11 %. The importance of controlling the biomass in the reactors was noticed for the quality treated effluent. The maximum BAS nitrification reached the maximum rate during the 90 ± 55 mg/L formaldehyde concentration in the influent and, in the same formaldehyde concentration, this rate started to decrease. In the tests for kinetics parameters, the formaldehyde consumption rates and COD concentration removal obtained for the aerobic biomass was higher than anaerobic biomass. The formaldehyde consumption was the first order reaction and it s rate depends on initial formaldehyde concentration, biomass localization in the reactors, formaldehyde concentration applied in the system and biomass adaptation stage. The maximum formaldehyde consumption specific rate was 0,457 mg HCHO/g STV.h for aerobic biomass.and your formaldehyde consumption rate was 0,325 ± 0,120 mg HCHO/g STV.h. For the anaerobic biomass, this values is less than it was for aerobic biomass and the maximum formaldehyde consumption specific rate was the 0,360 mg HCHO/g STV.h and the average was 0,135 ± 0,117 mg HCHO/g STV.h. It was possible to verify the aerobic biomass adaptation through the kinetics tests, after the adaptation its specific formaldehyde consumption specific rate was 0,404 mg HCHO/g STV.h

ASSUNTO(S)

biodegradação formaldeido biomassa cinetica quimica Águas residuais - purificação - tratamento biológico biodegradation formaldehyde biomass chemical kinetics sewage-purification biological treatment

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