Study Of Yeast-Sbr Process And Miroecological Community In Oil-Containing Wastewater Treatmentsystem By Yeast

Oily wastewater is an widely variety sources.This wastewanter accessing to water will cause serious environmental pollution. Conventional physical and chemical methods on the BOD removal capacity is poor, but in the practical application, biological methods are acclaimed with its low cost, small footprint, no special equipment, not bringing about secondary pollution.As a kind of extremely precious microorganism resources, yeast has good acidproof, osmotic pressure, and flocculation ability. Meanwhile, the yeast can convert the majority of non-toxic and organic nutrient-rich single-cell protein, which with high feeding value, therefore it widely applies in high concentration organic wastewater treatment.This article establishes the yeast-SBR wastewater treatment system. Simultaneously, molecular biological methods of PCR-DGGE and FISH were applied to analyze he yeast community structure in wastewater treatment system. And then we study the surface characteristics of yeast to understand the mechanism of mechanism of dominant yeast colonization. The results as follows:(1) 10 yeast strains on the oily wastewater system show good treatment effect. During the process of yeast SBR,ensure that sludge loading 0.25kg / (kg ? d), aeration time 6 h, settlement 2 h, N, P nutrition source volume is based on BOD: N: P = 100:5:1.It can make the system stable operation. When the yeast-SBR system stable, the system effluent COD is down to 200 ~ 350mg/L from 3000mg/L, COD removal rate reached 88% to 93%, oil content reduced to 45 ~ 100 mg/L from 1500mg/L, the removal rate is 93% to 96%, this system removed most of the organic pollutants in the oil-containing wastewater To meet the effluent discharge standards we use activated sludge post-processing, composed of yeast SBR as complex system. The complex system maked up 97.5% removal rate of COD and oil removal rate is up to 99%. This combination ensures the effluent COD values of 50~60 mg/L, the oil content of 10 ~ 20 mg/L, reaching to the Integrated Wastewater Discharge Standard (GB 8978-1996).(2) Using PCR-DGGE technique to analysis yeast community in yeast-SBR wastewater treatment system .The study shows that the strain of O2 or W1, O3, or G3, W2, unknown strain X1 can exist in the wastewater treatment system, and O2, or W1, unknown strain X1 are the dominant strains in the system.(3) For further testing, we use FISH technology to analysis the dominant strains. In the yeast-SBR system , yeasts occupy a favorable position as opposed to bacteria; probe can successful hybrid with the pure strains of O2 (Candida tropicalis), G3, O3, W1, W2 ,but only the hybridization signals of O2, O3 are strong. In the long run of yeast-SBR system, the number of yeast tracked by probe in oily wastewater treatment gradually increased. It indicates that the majority of strains in the sample were O2 or O3 with red fluorescence. Combined with the results of PCR-DGGE, we can see in the yeast-SBR system, O2 and O3 are absolutely dominant strains that can stably exist in the wastewater treatment system.(4) On the Mechanism of yeast colonization, hydrophobicity and flocculation is important factors of O2 and O3 to become the dominant strains.Emulsifier production and emulsifying ability of yeast strains directly affected the lipid degradation in wastewater, but emulsifying ability is just a factor for strains to be dominant, not the significant one.