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.