ProduÃÃo de biogÃs no tratamento dos efluentes lÃquidos de Coffea arabica L. em reator UASB para o potencial aproveitamento na secagem do cafà / Biogas production in the treatment of Coffea arabica L. wastewaters in UASB reactor for the potential use in the coffee drying.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

This work had the purpose of studying the biogas production in the treatment of the wet processing coffee wastewaters (ARC) in an anaerobic treatment system in laboratorial scale. The system used was composed of an acidification and equalization tank (TAE), a heat-exchanging, an upflow anaerobic sludge blanket reactor (UASB), a facultative aerated pond (LAF), an equalization tank and a gas tank, assembled in the Water Analysis Laboratory (LAADEG), of the Engineering Department at the Federal University of Lavras (UFLA). The ARC were produced from the wet processing of the natural coffee. The system monitoring was carried out by chemical and physical-chemical analysis; by the process operating monitoring; by biogas production quantification in UASB reactor and methane percentage analysis by gas chromatography and by biogas calorific power and permutation calculations. The gas chromatography analysis was carried out in the Center of Chemical and Prospection Analysis (CAPQ), of the Chemistryl Department at UFLA. The treatment was carried out for a period of 190 days and the pH was controlled for some periods by adding sodium hydroxide into the TAE or the UASB. Considering only the UASB reactor the maximum and minimum values obtained in the affluent ranged from 235 to 7064 mg.L-1 for COD; 200 to 3913 mg.L-1 for BOD5, 500 to 11.153 mg.L-1 for TVS and 4,5 to 7,8 for pH. In the outlet of the UASB reactor, the values were 39 to 2333 mg.L-1 for COD; 15 to 1300 mg.L-1 for BOD5, 272 to 2749 mg.L-1 for TVS and 6,2 a 7,9 for pH. The efficiencies of removing COD, BOD5 and TVS in the UASB varied from 32,7 to 93,1%, 44,7 to 94,6% and 24,2 a 90,2%, respectively. Considering the full system, the minimum and maximum values of COD, BOD5, TVS and pH in the inlet ranged from 305 to 7233 mg.L-1, 235 to 3562 mg.L-1, 665 to 4873 mg.L-1 and 4,5 to 7,8, respectively. The minimum and maximum values of COD, BOD5, TVS and pH in the system outlet varied from 13 to 1944 mg.L-1, 10 to 580 mg.L-1, 215 to 2487 mg.L-1, 6,6 to 8,7, respectively. The minimum and maximum values of the flow rate were 0,0043 to 0,0374 m3.d-1 and to VLR were 0,14 to 20,29 KgCOD.m-3d-1 . The efficiencies of removing COD, BOD5 and TVS of the system presented variations ranging from 46,4 to 98,2%, 64,6 to 97,9% and 41,9 to 89,0%, respectively. The theoretical biogas production in the UASB reactor presented values ranging from 0,537 to 0,580 m3.Kg-1COD and 0,537 to 0,580 m3.Kg-1BOD5. The methane percentage in the biogas presented values varing from 48,60 to 68,14%, which were caused by several conditions of the treatment process. The biogas mean specific mass obtained was 0,665 Kg.m-3. On a general view, the results obtained were satisfactory and close to the values of the researches mentioned in the theorectical reference of this work.

ASSUNTO(S)

biogas coffee wastewater construcoes rurais e ambiencia biogÃs methane Ãguas residuÃrias do cafà metano uasb reactor reator uasb

ACESSO AO ARTIGO

Documentos Relacionados