Influence of Extracellular Polymeric Substances on Anaerobic Biofilms Supported by Polyurethane Foam Matrices

Abstract

This work focused on the process of biofilm formation onto polyurethane foam matrices in differential horizontal anaerobic immobilized sludge reactors fed with a glucose-based substrate. The experiments consisted of monitoring the biomass colonization process of foam matrices, regarding to the amount of retained biomass, extracellular polymers (EPS) produced and morphological characteristics of the cells attached to the support. The excretion of polymers seemed to be determinant for the fast colonization process observed, probably being related to the cell fixation on the support. Three colonization phases could be observed based on the excretion of EPS. The two first phases lasted for 16 days and corresponded to the biofilm formation, while the third phase indicated the establishment of the biofilm. Rods are the main organisms attached directly to the foam and responsible for EPS production. The large EPS production onto packed-bed reactors may cause hydrodynamic troubles, thus increasing the head loss, decreasing the hydraulic detention time, and affecting the overall reactor's performance.

Morphological study of biomass during the start-up period of a fixed-bed anaerobic reactor treating domestic sewage

“…This fact led to the conclusion that such material participates in the first phase of biofilm formation. These results were similar to those observed by Ribeiro et al (2003), who used horizontal differential reactors fed with glucose-based wastewater. Rods and cocci were the predominant morphologies observed from the 2 nd to the 6 th week, mainly in the regions of the first phase of colonization.…”

“…In this sense, the support utilized to immobilize the biomass plays an essential role in these systems, and is directly associated with the cellular retention time, biomass concentration and microbial diversity. Polyurethane foam, which has been studied for many years for the adhesion of anaerobic microorganisms, has shown promising results (Huysman et al, 1983, Fynn andWhitmore, 1984;Calzada et al, 1984;Gijzen et al, 1988;Pascik, 1990;Varesche et al, 1997;Picanço et al, 2001;Ribeiro et al, 2003). However, although this support material provides a suitable environment for the adhesion of a mixed consortium of anaerobic microorganisms, its application in fullscale fixed-bed reactors must be carefully investigated, since it is a compressible material and the accumulation of solids or polymeric substances in the interstices of the bed can seriously impair the flow pattern in the reactor.…”

Treatment of Domestic Sewage in an Anaerobic–Aerobic Fixed‐bed Reactor with Recirculation of the Liquid Phase

“…Cubic matrices of polyurethane foam (1 cm per side) were used to fill the second stage of the reactor (anaerobic/anoxic) and the aerobic zone. This type of support has been used by several authors in anaerobic reactors [15][16][17] and was used by Fazolo et al [11] in a fixed-bed aerobic reactor for the treatment of anaerobically treated domestic sewage. The characteristics of the support material are listed in Tab.…”

“…pH in 6.7 AE 0.2 (11) 6.7 AE 0.2 (10) 6.9 AE 0.1 (14) 6.8 AE 0.2 (9) 6.9 AE 0.2 (6) 7.0 AE 0.2 (5) 6.8 AE 0.2 (47) pH e 6.8 AE 0.2 (11) 6.7 AE 0.1 (10) 6.7 AE 0.1 (14) 7.3 AE 0.3 (9) 7.4 AE 0.3 (6) 7.4 AE 0.2 (5) 6.6 AE 0.3 (5) 6.9 AE 0.2 (9) 7.2 AE 0.3 (9) COD in 589 AE 170 (12) 823 AE 180 (10) 597 AE 220 (14) 622 AE 145 (15) 579 AE 121 (16) 627 AE 319 (5) 553 AE 170 (47) COD e 228 AE 73 (12) 255 AE 70 (10) 140 AE 37 (14) 57 AE 27 (15) 44 AE 17 (16) 31 AE 10 (5) 61 AE 24 (5) 57 AE 28 (9) 54 AE 22 (9) COD rem 61 69 77 91 92 95 88 (54) 90 (9) 92 (9) BA in 99 AE 21 (11) 102 AE 15 (10) 119 AE 17 (14) 115 AE 14 (9) 109 AE 16 (6) 119 AE 20 (5) 105 AE 23 (47) BA e 138 AE 25 (11) 162 AE 27 (10) 143 AE 25 (14) 50 AE 27 (9) 41 AE 24 (6) 75 AE 36 (5) 46 AE 34 (5) 90 AE 37 (9) 86 AE 24…”

Acoplamento entre processos biológicos e oxidativos avançados para o tratamento de esgoto sanitário: degradação de fármacos e reúso seguro

“…Na determinação de cátions, a fase móvel utilizada foi H 2 SO 4 40 mmol L −1 .A concentração de metano, durante os testes de biodegradabilidade, foi determinada com um cromatógrafo a gás (GC2014, Shimadzu) equipado com uma coluna HP-PLOT Q. leito do reator foi composto por dois materiais-suporte para o crescimento dos microrganismos: argila expandida (granulometria média de 10 ± 5 mm) na primeira câmara anaeróbia; e cubos de espuma de poliuretano (densidade aparente de 23 kg m 3 , tamanho de poro de 543 ± 154 µm, área superficial de 43,8 m 2 g 1 e aresta de 1 cm) nas câmaras superiores (Figura 3.2). A argila expandida foi usada na primeira câmara por favorecer o crescimento de microrganismos acidogênicos(ORTEGA et al, 2001) que produzem os substratos para a comunidade microbiana aderida na espuma de poliuretano, suporte que permite o crescimento de uma grande diversidade de microrganismos(RIBEIRO et al, 2003). para 16, 14 e 12 h nas semanas seguintes.…”