Study On Biofuel Production And Decontamination Characteristics Of Chlorella Coupled With Domestic Wastewater Treatment

Domestic wastewater is a huge amount of wastewater resources.The use of nitrogen and phosphorus resources in domestic wastewater for microalgae cultivation is conducive to maximizing the resource utilization of wastewater.The coupling of the two will alleviate the high cost of microalgae cultivation costs.At the same time,the dual purpose of simultaneous oil production decontamination is realized,and the core of the coupling system operation is to improve biomass yield and oil yield.Chlorella vulgaris is one of the oil-rich microalgae species with fast growth rate,short culture period and high lipid content.This paper takes energy chlorella as the research object and investigates energy chlorella(Chlorella vulgaris)in the cultivation of artificial living wastewater under different growth modes,explored the relationship between energy growth and lipid accumulation and pollutant removal,and investigated the concentration of wastewater and wastewater from the perspective of growth characteristics and lipid accumulation.The nature and the tolerance and adaptability of environmental factors to find the optimal conditions for the operation of the coupled system;in order to improve the operating efficiency of the coupled system,this paper investigated the different concentrations of natural plant indole-3-acetic acid(IAA)and synthetic plants.The application of the regulator naphthaleneacetic acid(NAA)as a coupling system to produce additives,combined with the optimum phytohormone additive and different nitrogen source types(sodium nitrate,ammonium chloride,urea),phytohormone and nitrogen starvation culture synergistic effect on the coupling system Comparative study on the detergency characteristics of oil production;the coupling system under two culture systems of immobilization and suspension culture was discussed.Oil decontamination characteristics,in order to provide a theoretical basis for the effective operation of the energy chlorella domestic wastewater treatment system coupling.The main conclusions are as follows:(1)The culture solution is artificial simulated sewage.The growth characteristics and lipid accumulation of Chlorella pyrenoids in three growth modes: self,heterogeneous and mixed.In contrast,the biomass biomass and lipid yield of Chlorella vulgaris under mixed conditions were significantly higher.The other two culture methods are suitable as a training method for the coupling system.(2)The culture medium was artificial simulated sewage,and five environmental factor gradients and six sewage nutrient concentrations were set up to investigate the tolerance and adaptability of energy chlorella to domestic sewage.The energy chlorella normal growth in artificial simulated raw water,when the sewage concentration is 2 times the original water concentration,it shows growth inhibition;one-way analysis of variance and multiple comparison results show that the energy chlorella grows and lipid accumulation in different environmental factors The difference is significant.The results show that the optimal culture temperature of the coupling system is 25~30°C,the optimum pH range is 7~9,the optimum light intensity is 4500~6000lux,and the optimal salinity value is 0.1mol/L.(3)The effects of two plant hormones,IAA and NAA,on the growth and lipid synthesis of Chlorella were significant(p<0.05).2mg/LIAA promoted the best growth effect,followed by 2mg/L NAA.After 15 d culture,the biomass obtained was(525.867±5.907)mg/L VS(367.723±4.097)mg/L,which was the biomass obtained in the control group.2.48 times and 1.7 times;IAA and NAA concentrations were linearly correlated with lipid accumulation.IAA showed neutral lipid accumulation at 0.05~2mg/L,and NAA showed total lipid accumulation at 1~5mg/L.The biomass yield and oil yield of chlorella after induction with 2 mg IAA and 2 mg/L NAA were the highest(35.057±0.394)VS(24.515±0.273)mg/(L·d),(21.964±0.619)VS(14.376±0.091)mg/(L·d),compared with the untreated plant hormone control group,increased by 59.68%,41.23%,74.99%,and 61.78%.Respectively,two plant hormones on the growth and lipid of Chlorella Accumulation has a significant boosting effect.This study shows that phytohormone has a great influence on the microalgae culture system.The application of IAA and NAA can help to increase the yield of the culture system and the application conditions are in line with environmental benefits.2mg/L NAA is more suitable for Chlorellavulgaris culture as a plant hormones additive amount.(4)The effects of phytohormone additives and different nitrogen source types(sodium nitrate,ammonium chloride,urea)and plant hormones on the culture of Chlorella vulgaris under artificial breeding conditions were investigated.The results showed that the plants showed The growth-promoting and lipid accumulation effects of hormone administration are not limited by nitrogen type;in order to solve the phenomenon of biomass yield reduction of Chlorella vulgaris under nitrogen starvation conditions,the synergistic effect of plant hormones and nitrogen starvation on energy chlorella is studied.The effects of material yield and oil yield showed that under the nitrogen starvation environment,supplementation of plant hormones can prolong the logarithmic growth cycle of energy chlorella,and synergistic effect can improve the yield of oil while maintaining biomass yield.Conducive to ensuring continuous production.(5)Phytohormone not only helps to improve energy pellet biomass and oil yield,but also can significantly improve the nitrogen and phosphorus removal effect of the coupling system(p<0.05).Compared with suspension culture,it is fixed.The chemical conversion method can further reduce the use of phytohormone additives;and the removal rate of ammonia nitrogen,total nitrogen and total phosphorus in the sewage by the immobilized energy energy chlorella containing phytohormone reaches 97.5%,89.36% and 99.35%,respectively.Simultaneous oil production and decontamination characteristics have significant synergistic effects;in the immobilized culture,the treatment effects of total nitrogen,total phosphorus and ammonia nitrogen in the effluent quality of the coupled system all meet the above-mentioned Grade A standard as specified in the urban domestic sewage discharge standard.