| Digested piggery wastewater(DPW)is rich in nitrogen,phosphorus and potassium and other nutrients and zinc,magnesium and other trace elements,can be used as high protein microalgae or oil microalgae natural medium after appropriate treatment.The use of DPW for the cultivation of microalgae can not only reduce the pollutants in DPW,but also reduce the cost of microalgae culture,while harvesting high value-added products(such as: animal feed,biodiesel,etc.).Spirulina has a fast growth rate,high photosynthetic efficiency,and in the DPW has a certain degree of stain resistance,is the only greenhouse culture of micro-algae,because of it good spiral recovery,low recovery costs,has a great potential in the biogas slurry resource utilization.However,not all spirulina can grow in DPW.Compared with the optimized spirulina culture,the DPW is complex,and many compounds inhibit the growth of spirulina.In order to improve the utilization of DPW,the requirements of the use of Spirulina has a stain resistance,can be rapid growth in the DPW.However,in the actual application process,Spirulina alga species pollution resistance is not static.Therefore,in this study,the growth characteristics of the isolates and domesticated strains were studied by using the method of domestication of DPW,and the domesticated strain SP24 was used for outdoor large-scale breeding.The results are as follows:(1)A high-polluted blunt spirulina SP1 was screened from Jiaxing City's local DPW pool.After the continuous use of the laboratory,the stain resistance was gradually degraded,and after the artificial rejuvenation,it is recovered,but the growth rate in the DPW is reduced,so it can not meet the needs of large-scale production,the need to separate new algae species.(2)The resuscitation of the isolate SP2 was carried out by the method of domestication of biogas slurry.Among them,the regenerated strain could show high growth rate and biomass,and its morphological characteristics became close.The biomass of domesticated strain SP24 in Zarrouk and DPW was 17.2% and 13.2% higher than that of isolate SP2.(3)By using different culture medium to preserve the algae species,it was found that a single medium could not be used to protect the seeds.Zarrouk preserved algae grows faster and the algae activity was higher,but the cost was high and themorphology of algae was loose.Biogas slurry preservation of algae morphology can be maintained better,but the growth rate will slow down,activity decreased.Therefore,Zarrouk and biogas slurry can be combined to save the two methods,both to maintain the activity of algae can also make algae morphology does not change.(4)The growth rate of DPW in the indoor light reactor was almost the same as that of Zarrouk culture,which indicated that the SP24 had high resistance to sewage.In outside 140m2 large-scale cultivation the output reached 9.3 g · m-2 · d-1,use of the IASBR effluent culture,and there was no significant difference with the Zarrouk culture.However,the DPW culture saved 43% of the water resources,10% of the time cost,saving 50% of the nitrogen,40% of the phosphorus,and adding DPW can reduce the fracture,easy to harvest,after harvest Spirulina dry powder quality National feed grade Spirulina standard(GB / T 17423-1998). |
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