Effect of biomass adaptation to the degradation of anionic surfactants in laundry wastewater using EGSB reactors

AbstractTwo expanded granular sludge bed reactors were operated. RAB (adapted biomass) was operated in two stages: Stage I, with standard LAS (13.2mgL−1); and Stage II, in which the standard LAS was replaced by diluted laundry wastewater according to the LAS concentration (11.2mgL−1). RNAB (not adapted biomass) had a single stage, using direct wastewater (11.5mgL−1). Thus, the strategy of biomass adaptation did not lead to an increase of surfactant removal in wastewater (RAB-Stage II: 77%; RNAB-Stage I: 78%). By means of denaturing gradient gel electrophoresis, an 80% similarity was verified in the phases with laundry wastewater (sludge bed) despite the different reactor starting strategies. By pyrosequencing, many reads were related to genera of degraders of aromatic compounds and sulfate reducers (Syntrophorhabdus and Desulfobulbus). The insignificant difference in LAS removal between the two strategies was most likely due to the great microbial richness of the inoculum

Performance of carassius auratus with different food strategies in water recirculation system

The efficiency of a recirculation system for the cultivation of C. auratus, fed with natural and artificial diets was evaluated. The experiment consisted of four treatments with four replicates. The first two treatments used recirculation system and the last two static system. In the first and fourth treatment, animals were fed with brine shrimp biomass (50% CP), while in the second and third treatments a commercial flake ration (42% CP) was used. At the end of cultivation (60 days), water samples were taken from all experimental units and subjected to standard plate count for determining the density of mesophilic bacteria. Final weight (g), final length (cm), specific growth rate (% day -1 ) and weight gain (%) were significantly different (p<0.05) among tested diets, but the culture systems did not affect fish performance. There was significant difference (p<0.05) between systems for total ammonia and nitrite. Animals fed with brine shrimp biomass acquired more intense and brighter colors than those fed only with commercial flake food. The values of standard plate count of mesophilic bacteria ranged from 7.0 × 10 3 to 1.1 × 10 4 CFU.ml -1 . In this study we observed that C. auratus is a species tolerant to adverse water conditions, perhaps with increased stock densities, the recirculation system could play some positive role on the zootechnical performance of cultured animals.A eficiência de um sistema de recirculação para o cultivo de C. auratus, alimentados com dieta natural e artificial foi avaliada. O experimento consistiu de quatro tratamentos com quatro repetições. Os dois primeiros tratamentos utilizaram sistemas de recirculação e os dois últimos sistemas estáticos. No primeiro e quarto tratamento, os animais foram alimentados com biomassa de artêmia (PB 50%), enquanto nos tratamentos dois e três, com ração comercial em flocos (42% PB). Ao final do cultivo (60 dias), amostras de água foram coletadas em todas as unidades experimentais e submetidos a contagem padrão em placas para determinação da densidade de bactérias mesófilas. O peso final (g), com- primento final (cm), taxa de crescimento especí- fico (% dia -1 ) e ganho de peso (%) foram signifi- cativamente diferentes (p<0,05) entre as dietas testadas, mas os sistemas de cultivo não afetaram o desempenho dos peixes. Houve diferença sig- nificativa (p<0,05) entre os sistemas para os níveis de amônia total e nitrito. Os animais alimen- tados com biomassa artêmia adquiriram cor e brilho mais intensos do que aqueles alimentados apenas com ração comercial em flocos. Os valo- res de contagem padrão em placas de bactérias mesófilas variaram de 7,0 × 10 3 para 1,1 × 10 4 CFU.ml -1 . Neste estudo, observou-se que C. auratus é uma espécie tolerante a condições adversas de água, talvez com maior densidade de estocagem, o sistema de recirculação poderia desempenhar papel positivo sobre o desempenho zootécnico dos animais cultivados