小球藻对不同沼液添加量培养液的适应性及净化效果

Adaptation of chlorella to culture liquid with different biogas slurry adding proportion and its purified effect

以成分相对简单、未经灭菌的秸秆厌氧发酵后沼液和BG11培养基的混合液为培养液,以FACHB-5号和FACHB-8号小球藻为藻种,利用人工气候培养箱,在微藻培养温度为(26±1)℃,光照强度为4 000 lx,24 h连续光照,通气量为1.5 L/min,沼液添加比例为20%、30%和40%的条件下,系统研究秸秆厌氧发酵后沼液直接用于微藻养殖对微藻系统的影响。结果表明:试验采用的小球藻FACHB-8号藻种和FACHB-5号藻种均能较好地适应化学需氧量COD含量相对较高的秸秆厌氧发酵后沼液,但FACHB-8号藻种与FACHB-5号藻种相比对沼液的适应时间更短,适应能力更强;FACHB-8号藻种和FACHB-5号藻种均能较好的利用和转化沼液中的有机污染物,各试验组的COD去除率均大于90%,总氮去除率均大于96%,总磷去除率均大于92%。该研究可为沼液直接用于微藻养殖提供参考。

This study mainly focused on the following problems like the higher cost of adding nitrogen and phosphorus inchlorella culture; the delayed and ineffective use of biogas slurry containing rich nutrient elements just as nitrogen, phosphorus,and so on after anaerobic fermentation; the easily contaminated microalgae caused by undesired microbes in microalgaeculture; the higher cost of microalgae culture due to the biogas slurry pretreatments like sterilization and so forth when biogasslurry was serving as the culture medium; etc. The culture medium was the mixture of BG11 medium and biogas slurry fromstraw by anaerobic fermentation for 30 days. The biogas slurry fermented from straw was non-sterilized and relatively simplein composition. The algae species FACHB-5 and FACHB-8 chlorella were used. An artificial climate incubator was also used,in which the temperature for microalgae culture was kept at （26±1）℃, the light intensity was 4 000 lx, the light time was 24hours continuously, and the ventilation volume was 1.5 L/min. In the experiment, the total nitrogen at the beginning was 180,215 and 297 mg/L respectively in the experimental medium groups. The addition content ofbiogas slurry was 20%, 30% and40% separately; and the results showed that the total nitrogen content of culture liquid was reduced to 6, 8 and 12 mg/L withthe different biogas slurry treatments （20%, 30% and 40%）, respectively, and the removal rate of total nitrogen was more than96%. The total phosphorus content at the beginning was 14, 19 and 24 mg/L respectively in the experimental medium groupswith the addition ofbiogas slurry was 20%, 30% and 40%, separately; At the end of the experiment, they reduced to less than 2mg/L, and the removal rate of total phosphorus was more than 92%. Chemical oxygen demand （COD） content at the beginningwas 4 500, 6 993 and 9 366 mg/L respectively, in the experimental medium groups with the addition of biogas slurry was 20%,30% and 40%, and at the end of the experiment they reduced to 160, 400 and 540 mg/L respectively, the removal rate of CODwas more than 90%. The experimental results showed that both FACHB-5 and FACHB-8 algae species could well adapt tobiogas slurry which was relatively high in COD content from straw by anaerobic fermentation, and could well make the use ofand remove the organic pollutants from biogas slurry. Compared with FACHB-5 algae species, FACHB-8 algae speciesneeded shorter time to adapt, and had stronger adaptability to biogas slurry. What＇s more, there was a strong correlationbetween the degradation of organic pollutants and the growth of chlorella in every experimental medium group. The study maylay a theoretical foundation for the application ofbiogas slurry which will be directly used in microalgae culture, and may havethe magnificent significance for large-scale microalgae culture.