RemoÃÃo biolÃgica de nitrogÃnio de efluente avÃcola usando reator em batelada sequÃncial

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

Slaughterhouses and bird cold storage processing plants stand out as large polluters, particularly because of the large amounts of waste rich in organic substances, solids, oils and greases, nutrients, specially nitrogen and phosphorus. Nitrogen compounds removal from wastewater is usually accomplished through biological processes, by nitrification under aerobic conditions plus denitrification under anoxic conditions, being the nitrification the limiting step. This study investigated how initial ammonia concentration (NH4 +-N) and hydraulic residence time (HRT) affect the nitrogen removal from poultry wastewater by sequencing batch reactor (SBR) containing immobilized biomass, using manipueira (wastewater from cassava industry) as carbon source in the anoxic step. The experiment was driven in laboratory scale where three different levels of HRT were tested (12, 16 and 20 h) and three different levels of ammonia nitrogen concentration (80, 100 e 120 mg.L-1), by experimental planning of the factorial type, with nine treatments and four repetitions. The nitrification process performance was evaluated through efficiency of ammonia nitrogen removal (%), the denitrification process through efficiencies of nitrite and nitrate removal (%) and the whole process by ammonia nitrogen removal. During the nitrification and denitrification processes parameters like pH, temperature and alkalinity were monitored. The results show that both HRT and ammonia nitrogen concentration were significantly influent, with significance level equal to 5% (alpha = 0.05). The best results were obtained at the HRT range between 16 and 20 h and at the initial ammonia nitrogen concentrations range between 80 and 100 mg.L-1. In these ranges, the best results concerning removal efficiency of ammonia nitrogen (NH4 +-N) in the nitrification step, nitrite (NO2 --N) and nitrate (NO3 --N) in the denitrification step, and nitrogen removal considering the complete process (nitrification plus denitrification), were, respectively, 95, 94, 97 and 78%. Less satisfactory results were found for all variables analyzed in HTR 12 h to all concentrations of ammonia nitrogen tested and for ammonia nitrogen concentration of 120 mg.L-1 at the HRT 16 and 20 h. Alkalinity and pH levels developed in the expected way during the processes of nitrification and denitrification. The SBR showed to be efficient at nitrogen removal from bird cold storage anaerobic wastewater, being able to be used as post-treatment system.

ASSUNTO(S)

engenharia agricola desnitrificaÃÃo nitrificaÃÃo denitrification hydraulic residence time nitrification tempo de detenÃÃo hidrÃulico nitrogÃnio amoniacal ammonia nitrogen

ACESSO AO ARTIGO

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