畜禽粪便固液分离技术特点及效率评估

该文对常用畜禽粪便固液分离技术进行分析,评估出各分离技术的优缺点、适用对象、分离效果和性价比,为企业选择粪便固液分离设备提供参考。研究结果表明:重力分离技术成本最低,分离粒径小于1 mm的有机物效果最好,但分离后固相含水率过高(90%),一般作为其他技术的预处理。筛分技术对于分离大粒径的有机颗粒物最有效,投资相对小,运行费用低;但对氮磷等营养元素分离效率较低,分离后的固相的含水率偏高,分离产物可用于固态发酵。压滤技术提高了磷元素的分离效率和固相含水率,但运营成本也增加,分离产物可用于有机肥生产。沉淀离心技术对去除细小颗粒最为有效,并能够去除氮磷元素,但运营成本太高,在中国推广难度大。絮凝剂能和大多数的分离技术结合使用从而提高分离效率。所有固液分离技术都不能分离畜禽粪便中的挥发性脂肪酸,因此也不能有效去除液相中的生化需氧量和臭味。多种分离技术的联合使用,在提高营养物质的分离效率的同时,降低固相的含水率将是未来技术发展的主要方向。

Characteristics and efficiency evaluation of livestock slurry separation technologies

Abstract: The separation efficiencies of different separation technologies of livestock slurries were studied in this paper. The advantages and disadvantages of these techniques were evaluated so as the suitable livestock slurries. Results showed that the moisture content of solid phase from gravity separation technologies was too high (>90%), although it had the best separation efficiency on organic particles with diameter less than 1mm. Static rundown was the most widely and easily used separator, it was economic especially in large scale. The trafficable sediment basin could be used as the pretreatment of anaerobic digestion or other separation technologies. The cost of rotating screen and vibrating screen was higher than that of static rundown, and always need more maintenance. All mechanical screening technologies were efficiently to remove the fibrous, but were poorly on the soluble nutrient. The solid state from all mechanical screening could be used for fermentation directly. The presses technologies can enhance the separation efficiency of the phosphorus as well as the TS content in the solid state, but increased the costs simultaneously. Decanter centrifuge worked most efficiently, especially on phosphorus and fine particles, but was ineffectively to deal with dilute slurry. Decanter centrifuge was the only technique which could produce seemingly clarifying liquid state that can be used in many ways but the investment and manage cost were too high to popularize in China. Scarcely any technologies could separate the VAFs efficiently, so the BOD and odor cannot be removed in the same way. Combination different technologies to enhance the separation efficiency while decrease the water content will be the way of future technology development.gies to enhance the separation efficiency while decrease the water content will be the way of future technology development.