Simultaneous treatment and enrichment of total phosphorus from livestock sewage using hydrate technology

The presence of phosphorus in livestock sewage is a key factor that causes eutrophication and the degradation of ecological water quality. Cyclopentane (CP) hydrate-based water treatment technique was utilized for the efficient total removal of phosphorus in effluents. This study assesses the treatment effectiveness and enrichment potential of hydrate technology when applied to real-world samples, specifically livestock wastewater. The treatment process was applied under atmospheric pressure and optimized appropriate conditions comprising the CP-to-sample volume ratio of 1:4, reaction duration of 3 h, and temperature of 2 °C because of the high subcooling and ability to enhance the number of hydrate crystals formed along with water. In addition, various methods, such as vacuum filtration, cold centrifugation, and washing, were employed for the effective and comprehensive removal of phosphorus from water samples with the efficiency exhibited from approximately 30 % to 80 %. The structure and composition of the CPHs formed in wastewater were analyzed via Raman spectroscopy and the phosphorus content was determined according to ISO 6878:2004. After a single-stage hydrate process without pretreatment and posttreatment, the water recovered from the extracted hydrates showed that the phosphorus removal efficiency in livestock sewage was approximately 85 % with a remarkable water recovery above 25 %. The study findings provide insights into the development of hydrate-based treatment technology for the removal of phosphorus and explore opportunities for resource enrichment and recovery from sewage.