ホタテ貝殻を利用した晶析法によるメタン発酵消化液からのリン回収プロセスの開発

リン回収

In this study, we aimed to develop a process for recovering phosphorus from methane fermentation digested liquid by crystallization on the surface of scallop shell. Scallop shell powder was put into methane fermentation digested liquid at appropriate pH, and HAP (hydroxyapatite) was crystallized on the surface of the shell. HAP on the shell powder was dehydrated to recover phosphorus. Fabricatel system used a fluidized bed reactor for crystallization method. Measurement parameters were influent phosphate concentration, effluent phosphate concentration, and pH. We performed a model experiment using a fluidized bed reactor. It took 3 hours to treat all raw water which was 12 L of phosphorus solution prepared 50 mg-PO4/L. As the result of this experiment, we achieved 82.6% of phosphorus recovering efficiency. But when we tried to recover phosphorus from methane fermentation digested liquid, the organic matter blocked HAP crystallization. So the recovering efficiency was less than that of model experiment. The phosphorus recovering efficiency improved in condition that methane fermentation digested liquid was diluted three times and reduced concentration of the organic matter.