| The AEM laboratory of Henan Normal University screened a fungus which named Phanerochaete chrysosporium, can promote formation of aerobic granular sludge, increase decoloration effects of the dye wastewater and play the role of phenol degradation. P. chrysosporium could produce chlamydospores when Mn2 + has been added.The chlamydospores can resist impaction of extreme environmental and be more adaptability. The optimized liquid fermentation medium for the production on biomass and chlamydospores of P. chrysosporium contained: 37 ℃ of the fermentation temperature, glucose 15 g/L, yeast extract powde 6 g/L, and p H 4.5. The production on biomass and chlamydospores of P. chrysosporium were 17.92 g/L, 5.03 × 108 cfu/g.In this study, a homogenizer was used to explore the crushing technology of P. chrysosporium chlamydospores, and the plate method was used to count the number of active chlamydospores. Under the experimental conditions, 1g chlamydospores that dilute 10-fold with sterile water and crush 8min, the result show that the maximum production on chlamydospores is 3.25 × 108 cfu/g. the chlamydospores After pulverization, the chlamydospores were spreaded on PDA plates, and cultivated at 37 ℃ for 48 h, the total plate count of active chlamydospores were 3 × 108 cfu/g.SVI of sludge decreased with time during the operation. On day 9, SVIs in R1 and R2 were 98 m L/g and 76 m L/g, respectively. SVI in R2 was lower than those in R1 during the wastewater treatment. MLSS curves of R1 and R2 indicate a sharp decline during the start-up phase because the majority of dispersed sludge with poor settling ability was washed out with the effluent. After day 4, the biomass in the reactors increased with propagation of microbes, and MLSS curves had an ascend trend. MLSS concentration in R2 is higher than that in R1 throughout the test period.Compared with R1, COD removal efficiency of R2 was improved significantly. On day 5, 83.3 % and 95.1 % of COD removal rates were obtained in R1 and R2, respectively. After day 6, the COD removal in R2 was kept at the level of 95.2-99.0 % after 6 h treatment while COD removals in R1 were below 88.0 % during the 30-day test. During the run of reactors, ESS curves of the two groups of reactors decreased sharply with time. On day 6, ESSs of R1 and R2 were 153 mg/L and 94 mg/L, respectively. After day 7, the curve in R2 became stable, and ESS values were lower than 85 mg/L. R1 had the higher ESS in contrast with R2. After day 15, the phenol concentration was higher than 1.0 g/L, and ESS curve in R1 was fluctuant in the range of 98-143 mg/L.Phenol biodegradation performance of R1 and R2 was compared using a phenol removal experiment. A more rapid decrease in phenol concentration was observed in R2 than in R1.The maximum specific degradation rate(SDR) of sludge in R2 reached 1.47 g phenol g-1 VSS day-1 at 600 mg/L of phenol. In addition, sludge performance in R2 remained stable at phenol concentration as high as 2000 mg/L. SDR of sludge in R2 at different phenol concentrations, shows a good fit between the degradation data and the Haldane equation. The higher kinetic parameters of Vmax(5.7 g phenol g VSS-1 d-1), Ks(570 mg/L) and Ki(270 mg/L) show that the sludge developed a phenol uptake system to counteract the adverse effects of phenol inhibition. The activated sludge in R1 could degrade phenol at a maximum SDR of 0.85 g phenol g-1 VSS day-1 when phenol was 400 mg/L. After a 12 h treatment, 79 % removal efficiency was achieved in R1 only when phenol concentration was below 1200 mg/L.A total of 68602 trimed sequences were obtained. The Chao1 was used to estimate the bacterial richness of sludge sample. On day 3, the Chao1 estimators of sludge in R21(1462) was significantly lower than that of sludge in R2(2666), and this phenomenon can be explained by the addition of amounts of the chlamydospores are to R1. On day 15, the Chao1 estimator of sludge in R1 was increased to 2633, and on day 30, it is higher than that of sludge in R2.On day 15, the Chao1 estimator of sludge in R2 was increased to 2633, and on day 30, it is higher than that of sludge in R1. During the test, sludge in R1 had a lower Shannon diversity index in contrast with R2. The 4217 OTUs of six sludge samples were grouped into 21 phyla and most of them was affiliated to Actinobacteria, Bacteroidetes, Candidate, Firmicutes and Proteobacteria(RA ≥97.9 %), suggesting that the five phyla are mainly responsible for the bacterial phenol degradation ability in SBR. Bacterial community structures in two reactors were further compared at the genus level. The OTUs of bacteria were grouped into 302 genera, and a part of them in sludge samples(27.69-38.70 %) had no taxonomic rank. One hundred prevalent genera occupying to 96.33-99.29 % of RA were selected and further analyzed, shows that the prevalent bacteria in sludge samples were mainly distributed in three groups Groups A, B and C. The RA of Group A in R1 is significantly higher than that of R2 although their RAs in both reactors decreased with time. Group B may be the main bacterial population in bioaugmentation reactor. Bacteria in Group C had the same trend in both reactors. But, same as Group A, R1 is also higher than R2 in RA during the treatment, and on day 30, the RAs in R1 and R2 were 9.44 % and 2.09 %, respectively. From the fact above mentioned, we can conclude that the bacteria in R2 mainly ditributed in Group B, but in R1, the bacteria is unconcentrated, the bacteria from Groups A, B and C all take a major proportion of the total bacterial population.A total of 28463 sequences were obtained and by phylogenic analysis of the 18 S r RNA sequences. The eukaryal community richness and diversity were evaluated by Chao1 and Shannon index. On day 3, the Chao1 estimators of sludge in R1 were significantly higher than those of sludge in R2. After day 3, the Chao1 estimators of sludge in both reactors increased, and day 30, the Chao1 estimators of sludge in R1 is 1.8 time higher than that of sludge in R2, showing that the eukaryal community richness was significantly increased. During the test, sludge in R1 had a lower Shannon diversity index in contrast with R2, indicating the addition of chlamydospore reduces the eukaryal community diversity. The enhancement of community richness as well as reduction of community diversity means that the some specific eukaryotes in R1 were enriched. On day 3 and 15, fungi and microalgae occupy a position of prominence in R1,including Agaricomycetes, Saccharomycetes, Trebouxiophyceae. Protozoa and metazoan occupy a position of prominence in R2 on day 3-30. |
PDF Full Text Request