| Mycelial pellets(MPs)are formed by self-flocculation of filamentous fungi.It has the characteristics of large specific surface area,excellent adsorption performance,fast settling speed,easy solid-liquid separation,high biocompatibility,and no secondary pollution.It is ideal for immobilization of functional bacteria Carrier.At present,MPs as a biomass carrier in engineering applications are mainly troubled by two problems: on the one hand,there is no complete evaluation system and clear time standard from inoculation of spores to pellets;on the other hand,the advantages of MPs formed by different filamentous fungi are different,and MPs produced by a single filamentous fungus have insufficient performance in the application of biomass carriers.Therefore,this project first constructed a time standard and evaluation system for MPs to be pelletized,and then through the combination of different filamentous fungi and the addition of biological flocculants,to explore its impact on the overall performance of the biomass carrier,and then load the functional bacteria MPs was added to the SBR reactor to study its effect on the removal of pollutants and the physical and chemical properties of the sludge,and its mechanism was analyzed from a microscopic point of view using high-throughput sequencing technology.This experiment completed the optimization of the biomass carrier culture conditions in the experiment by shaking flask culture.The study found that the optimal culture time of MPs is 48 h to 72 h.The structure of MPs at this stage is stable,and the average particle size is about 2 mm.The EPS content is high,the impact resistance is strong,it’s hard to separate and the sedimentation performs well.It is a good biomass carrier material.At the same time,using it as the cultivation time of MPs can increase the utilization rate of the cultivation equipment.In practical applications Higher economic efficiency.Adding a suitable concentration of bioflocculant can significantly increase the structure size of MPs,promote the secretion of EPS by MPs,increase mycelial density,and improve the structural stability of MPs in practical applications.In this experiment,the optimal dosage of bioflocculant It is 40 mg/L.The combination of different strains can significantly improve the comprehensive performance of MPs.The best combination of mixed MPs in this experiment is: the best spore inoculation amount of Aspergillus niger 557 is the total inoculation amount,according to Aspergillus niger 557: Phanerochaete chrysosporium 507=2:1 for inoculation.By adding MPs loaded with aerobic denitrifying bacteria to the SBR reactor,it completed its research on improving the performance of activated sludge.The results showed that: after 40 days of operation of each system,compared with the addition of free aerobic denitrifying bacteria for the sludge system bio-enhancement.After the MPs loaded with functional bacteria are added to the reactor,the denitrification effect of the system has been continuously strengthened.The final total nitrogen removal rate has increased by 9%,and the particle diameter of sludge has hiked up by 16.7%on average.The EPS content has increased by 46.4%,the formation time of aerobic granular sludge has been shortened by 10 days,the sedimentation performance of the sludge has been significantly improved,and the activity of the microbial phase of the system has been improved.Through the analysis of the microbial community structure of the sludge samples,it is confirmed that MPs as a biomass carrier can maintain the functional bacteria,and can significantly increase the relative abundance of the key flora related to the removal of pollutants in the system,and accelerate the maturity of the construction The microbial community structure of the system improves the treatment effect of the reaction system. |
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