Research On Microalgae Bioenergy And Biogas Slurry Resource Treatment Based Chlorella Spp. Utilization

Energy depletion and environmental pollution are two major problems today.Microalgae lipids are the most promising new energy sources among the raw materials of biodiesel in current,yet the costs hindering the industrialization development of the microalgae energy.Meanwhile,With the scale and quantity increasing of livestock farm,the biogas engineering and corresponding anaerobic fermentation by-products increased sharply,the utilization technology of biogas slurry is urgently to develop.This study aims at the emission standardization of biogas slurry and the low-cost cultivation of energy microalgae.The comparison of microalgae lipid extraction methods,the study of Chlorella spp.growth and lipid accumulation factors,and the results evaluation of biogas slurry purification and micro-algae cultivation under the bio-reactor were carried out.Main results are as follows:?1?The growth and lipid accumulation of three Chlorella spp.?F-5,F-1068,F-ART?under different nutritional conditions were studied.Results showed that F-5 and F-1068 grew batter in 10 times diluted biogas medium,while the growth of F-ART was inhibited at all the 3 concentrations and therefore it's not suitable for the biogas slurry medium system.F-5 chlorella grew best in biogas slurry and was most adaptable,the maximum absorbance value?OD?was 0.778.biomass was 175.87 mg/L,lipid production was 34.67 mg/L,and lipid production has no significant difference?p>0.05?under 3 different nutritional conditions.?2?The growth and lipid accumulation of Chlorella spp.?F-5,F-1068?under different initial pH conditions were studied.The results told that the optimum growth of F-5 and F-1068 is 6 and 7 for each,and the optimum lipid production was obtained from the initial pH of 7 and 6,and significant differences was observed in the results with the other conditions?p<0.05?.?3?The growth and lipid accumulation of Chlorella spp.?F-ART,F-5,F-1068?under Norfloxacin stress were studied in comparison.The results show that the concentrations of Norfloxacin which within the scope of the study can promote the growth of Chlorella spp.The biomass of F-ART had been greatly influenced by Norfloxacin,the biomass under 10 mg/L concentration of Norfloxacin was 253 mg/L after 12 days,and was 6 times of the control.For F-5 and F-1068,Norfloxacin also promotes the biomass in some degrees,however,at the expense of low lipid content,and declines in the lipid production under the condition of high concentration of Norfloxacin ultimately.?4?The system of coupling biogas slurry resource treatment and microalgae lipid production by Chlorella pyrenoidosa?F-5?was established.The effects of biogas slurry purification and Chlorella pyrenoidosa?F-5?cultivation were studied by using solar assisted microalgae bio-reactor.It turns out that F-5 Chlorella pyrenoidosa adapted the bio-reactor very well,the maximum absorbance value?OD?was up to 0.413,when biomass was 59.06 mg/L,and the lipid production was 23.85 mg/L.The net removal amount of Total Nitrogen?TN?,Ammonia Nitrogen?NH₄⁺-N?,Total Phosphorus?TP?,Chemistry Oxygen Demand?COD?were:121.75,58.20,13.09 and 1726.10 mg/L,and the removal rates were:58.64%,95.25%,87.78%and 87.60%,respectively.The results suggested that F-5 can be used to produce algae energy combined with the purification of the wastewater from livestock farms,and the groundwork was proposed by this study for the large-scale cultivation of Chlorella vulgaris with biogas slurry.?5?The effects of three kinds of lipid extraction methods were studied to extract lipid from Chlorella vulgaris F-ART?direct Leaching,Soxhlet Extraction and Bligh method?.The results showed that the extract rate of lipid by usingBligh method with which methanol-chloroform-water as the extract phase is significantly higher than other methods?p<0.05?.