| Industrial wastewater had potential threats to the ecological environment and people's health.The biological treatment unit had become an important part of industrial wastewater treatment because of its many advantages in technology,cost,operation effect and management.Especially with the development of microbial immobilization technology,the application of this technology to the treatment of various industrial wastewaters had gradually attracted people's attention.When using the traditional activated sludge method,the effluent was unstable due to the complicated and variable wastewater quality,poor biodegradability and biotoxicity,and microbial immobilization technology had brought a new direction for the treatment of industrial wastewater.The choice of immobilized carrier was an important part of the successful implementation of this technology.The problems of conventional carrier materials in terms of structural properties affected the application of immobilized microorganisms in industrial wastewater treatment.Therefore,it was very important to find a carrier with good biocompatibility,certain adsorption capacity,large specific surface area,fast film-hanging speed and excellent physical properties.Graphene oxide?GO?had been extensively studied due to its special properties,and considering the biocompatibility and mass transfer performance of the carrier,the natural carrier and the graphene oxide material were selected in this experiment to prepare the immobilized carrier.In this paper,sodium alginate and graphene oxide were selected to prepare aerogels carrier.The mycelial pellets?MP?were prepared and optimized using the heterotrophic nitrifying fungus Penicillium sp.L1.The performance and influencing factors of the treatment of wastewater by two kinds of carrier-immobilized microorganisms were investigated.It not only provided new options for microbial immobilization carriers,but also accumulated experience in the treatment of industrial wastewater.The Penicillium sp.L1 was used as the research object to prepare and optimize the L1 mycelial pellets.The experimental results showed that:?1?pH=7,the inoculation of 60 and the recultivation time of 3 d were the optimal optimization conditions.The optimized L1 mycelial pellets had a regular net structure and uniform and developed mesh,and the mycelium structure was thick and complete.?2?Mycelial pellets immobilization system?IS-MP?had higher ammonia nitrogen degradation rate in simulated wastewater?NH4+-N degradation ratio in 12 h:experimental group was 85.67%and control group was 69.19%?,and the degradation advantage was more prominent in mixed wastewater.?3?The mixed wastewater was prepared in a shake flask at a ratio of 2:1?simulated wastewater:coking wastewater?to study the treatment capacity of IS-MP in coking wastewater.The experimental results showed that the treatment effect of IS-MP was better than free bacteria.?4?The optimal inoculum for IS-MP was 90.The GO-SA carriers were prepared using GO and sodium alginate?SA?and optimized,and its properties were studied.The experimental results showed that:?1?The optimal ratio of GO-SA was 1:10.Increasing the GO content can effectively increased the strength of the carrier,and also slightly improved the water treatment effect after loading the microorganisms.?2?The GO-SA carriers had a density of 0.97 g/cm3 and a specific surface area of 14.41 m2/g.It was porous,stacked and rough on the structure,and had good microbial adsorption and biocompatibility.?3?The adsorption of NH4+-N by GO-SA carriers conformed to the quasi-second-order kinetic equation and the Freundlich isotherm model?1/n=1.767?.The adsorption amount and adsorption rate increased with the increased of the initial NH4+-N concentration.?4?The optimal ratio of GO-SA is1:10.Increasing the GO content could effectively improve the strength of the carriers,and also slightly improve the water treatment effect after loading the microorganisms.?5?In simulated wastewater,graphene oxide/sodium alginate immobilization system?IS-GO/SA?had higher microbial growth rate and pollutant removal rate than free cells at low temperature,and also had a certain buffering capacity for pH change in wastewater.?6?The mixed wastewater was prepared in a shake flask at a ratio of 2:1?simulated wastewater:coking wastewater?to study the treatment capacity of IS-GO/SA in coking wastewater.The experimental results showed that the treatment effect of IS-GO/SA was better than free bacteria,and it had a greater advantage than IS-MP.?7?GO-SA had the ability to remove the color of wastewater and provide more protection for microorganisms in harsh environments.?8?The optimal inoculum size for IS-GO/SA was 15.The bacterial consortium FG-06 was immobilized with GO-SA materials and the treatment efficiency on mixed wastewater was studied in moving bed biofilm reactor?MBBR?reactor.The experimental results showed that:?1?The decrease of ambient temperature leaded to the decrease of COD removal rate,the increase of aeration amount significantly increased the NH4+-N degradation rate of the reactor,the influent quality affected the removal rate of each pollutant significantly.?2?Under the same conditions,IS-GO/SA was significantly better than activated sludge system?ASS?.?3?Only the biological treatment unit,the overall NH4+-N and COD removal effect of the reactor was not satisfactory,but the removal rate of phenol was maintained at 99%.?4?Under the optimal conditions of the IS-GO/SA,the degradation rates of NH4+-N and COD were 97.1%and 91.9%,respectively. |
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