Remoção de DQO e nitrogênio de efluente de microcervejaria em biorreator de leito empacotado com aeração intermitente

Abstract

The brewing industry, whether large or small, generates large amounts of effluent with high organic concentration, in which parameters such as Chemical Oxygen Demand, pH, Total Kjeldahl Nitrogen and Total Solids can vary according to the nature and raw materials used, the type of beer produced, the process carried out and the amount of water used in the cleaning steps. Thus, the effluent must be properly treated before being disposed of in the environment. Microbreweries often do not have the space or resources to have an Effluent Treatment Plant, and due to the growth in the number of microbreweries in the sector, it is important to think about how this effluent will be properly disposed of. Studies show that it is possible to use a single reactor to remove COD and NT in sanitary sewage, and this configuration to treat microbrewery effluent, which normally operates in batch and often does not have the conditions to install an ETE in its space, can be promising. To address the various issues related to brewery effluents, this thesis is divided into 3 chapters. Chapter I deals with the history of beer, the market, the production process and generation of effluents in beer production. In a microbrewery in the city of Ponta Grossa- PR, the production process of American Pale Ale and Bernstein Amber Ale beers was monitored. It was observed that it took about 4.3L of water to produce 1L of American Pale Ale beer and 4.7L to produce 1L of Bernstein Amber Ale beer. Of the total water consumed, around 70% becomes a polluting effluent, with COD values abovethat can vary between 2000 and 4000 mg L-1 and NTK between 25-80 mg L-1. Chapter II reports the results of the evaluation of a packed-bed reactor with intermittent aeration and recirculation to treat microbrewery effluent, which had an average COD of 2680 mgL-1 and NTK concentration of 60 mg L-1. The reactor was operated with intermittent aeration, constant temperature of 30°C and in a batch regime. Mini BioBobs® were used as a support medium for the growth and adherence of microorganisms, which allowed the formation of aerobic and anoxic zones in the reactor. The reactor was operated with different total aeration times (h), ranging from 3h to 15h, TDH of 12h, 16h and 20h, with a COD/TKN ratio varying between 40 and 100. It was possible to obtain values from 74.6% to 98.1% for COD removal and from 76.6% to 95.3% for NT. The best responses were obtained in the condition with 12h TDH, 40 COD/TKN ratio and 9h total aeration time, with effluent showing 45 ± 9 mg COD L-1, 6.7 ± 0.7 mg NTK L-1, 0 .75 ±0.15 mg N-NH4+ L-1 and 0.10 ±0.01 mg N-NO2L-1. Chapter 3 shows the results of the evaluation of the cytotoxic, genotoxic and mutagenic potential of microbrewery effluent treated in a packed-bed batch reactor with intermittent aeration, through tests with Allium cepa bulbs. It was found that the treatment in a structured bed reactor with intermittent aeration, in batch and recirculation reduced the toxicity of the brewery effluent.