C/N对蓝藻好氧堆肥腐熟及无害化进程的影响

Influence of C/N Ratio on the Composting Effect and Secure Utilization of Cyanobacteria

为探索和优化脱水蓝藻藻泥好氧堆肥无害化处理工艺参数,利用堆肥反应器,研究了C/N分别为5(T1)、15(T2)和25(T3)的处理对蓝藻藻泥腐熟进程及微囊藻毒素(MC)降解速率的影响。结果表明,堆肥过程中各处理间的pH、总碳量及其形态、总氮量及其形态、总磷含量、总钾含量、种子发芽指数差异显著。与蓝藻自然堆置相比,添加辅料增加堆体C/N可提高蓝藻的腐熟速度。堆肥35d后,T2和T3处理的堆肥成品均已满足有机肥行业标准,种子发芽指数均高于80%;但MC-LR和MC-RR仍有较大的降解潜力,从无害化的角度考虑,蓝藻高温堆肥时间不应少于50d。C/N过高增加了氮素的损失,如何进一步降低氮素的损失,提高堆肥过程中MC的降解将是今后蓝藻堆肥研究的重点。

The efficient collection of cyanobacteria is an effective way to reduce the amount of cyanobacteria and its risk of bloom again.Aerobic composting of dewatering cyanobacteria by collection could change waste into resource.However,the residue of microcystins（MC）after aerobic composting should be considered in view of its application safety.To explore and optimize the aerobic composting technology of dewatering cyanobacteria,an composting using aerobic composting reactors was conducted,in which 5（T 1）,15（T 2）and 25（T 3）C/N ratio were installed during the composting.The objective of this study was to analyze the composting speed and the degradation of MC in dewatering cyanobacteria.Results showed that pH,contents of carbon,nitrogen,phosphorus and potassium,germination index were significantly（P 0.05 or 0.001）different between the three treatments.The composting speed significantly enhanced in treatments of T 2 and T 3 compared with treatment of T 1.After 35-d composting of cyanobacteria,the total nutrient content in T 2 and T 3 treatments met the requirement of the national industry standard of organic fertilizer.Meanwhile,the germination index in those treatments were more than 80%.However,the degradation potentials of MC-LR and MC-RR were still high after 35-d composting.For the secure utilization purpose,the high temperature composting time of cyanobacteria should be more than 50 days.Nitrogen loss would be larger with C/N ratio of the materials of composting.The research hotspots were to reduce nitrogen loss and to enhance the degradation of MC during the aerobic composting of dewatering cyanobacteria.