[Pilot-scale cultivation of Spirulina plantensis with digested piggery wastewater ]

The swine waste pretreated with coagulation sedimentation was used for the outdoor pilot-scale cultivation of Spirulina platensis isolated from digested piggery wastewater (DPW) in a raceway pond. The growth of S. platensis and removal of nitrogen/ phosphorus were studied, moreover, the conversion efficiency of total nitrogen (TN) or total phosphorus (TP) from DPW to S. platensis was calculated. On this basis, the existing problems and countermeasures during outdoor pilot-scale culture were analyzed and summarized combined with the laboratory research. We conducted 6 batches culture experiments, only 3 of which could reach the S. platensis harvest requirements (D560 >0. 8). Meanwhile, the 3 successful batches achieved removal of COD, ammonia nitrogen, TN, TP with corresponding 28. 6% -48. 5% , 0.4% -48. 5% , 41. 8% -48. 6% , 14. 3% -94. 5% , and the conversion efficiency of TN or TP from DPW to S. platensis reached 12. 1% -98. 5% , 21.2% -83.7% , respectively. High concentration of ammonia nitrogen and insect attack of remaining egg hatching in the pretreated swine waste were the main factors to cause the slow-growing of the 3 batches of S. platensis. Therefore, it is highly necessary for the removal of ammonia nitrogen with biological treatment technology and insect eggs with membrane to achieve a stable high productivity.