猪和奶牛粪便的粒径及养分分布对固液分离效率的影响

以猪、奶牛粪便为材料,按<0.15、0.15～0.5、0.5～1.0、>1.0mm不同粒径,分析了猪、奶牛粪便粒径分布,同时分析了4种不同粒径颗粒中N、P、K养分含量,采用XY型螺旋式畜禽粪便固液分离机,在0.5、1.0mm两种孔径筛网下,进行了固液分离,分析比较了机械固液分离对相应粒径粪便固形物及养分回收效率。结果表明,猪、奶牛粪便粒径分布以<0.15mm小颗粒为主,占其粪便重量的57.99%～68.34%,奶牛粪便颗粒粒径大于猪粪便,仔猪与育成牛粪便粒径小于育肥猪与泌乳牛粪便。猪、奶牛粪便中N、P、K养分近80%以上呈水溶性或存在于<0.15mm小颗粒之中。粪便机械固液分离获得的固形物与固形物中N、P养分回收比例高于相应筛网孔径粪便颗粒与养分所占比例,奶牛粪便固形物回收率为45.5%,远高于猪粪的27.8%,N、P养分回收率分别为7.14%～19.71%、7.38%～21.18%。

Effect of Particle Sizes and Nutrient Contents in Swine and Cow Manures on Efficiency of Solid-liquid Separation

The aim of this study is to determine the effect of the particle sizes and nutrient contents in the swine and cow manures on the effi-ciency of solid-liquid separation with the XY screw separator. The fresh manures were sieved with sieves of 0.15, 0.5 and 1.0 mm, and ana-lyzed for the contents of N, P and K in the fractions of <0.15, 0.15～0.5, 0.5～1.0 and >1.0 mm particles. The manures were also separated with the XY screw solid-liquid separator with 0.5 and 1.0 mm sieves. The distributions of particles and nutrients in the two particle fractions were analyzed. The fraction of <0.15 mm particle in the manures was the predominate fraction in the range from 57.99% to 68.34%, with the order being dairy manure< veal, grower swine< nursery swine. The 80% contents of NP and K in the manures were soluble and in the fraction of <0.15 mm particle. The separation efficiencies with the XY screw solid-liquid separators were 27.8% for swine manures and 45.5% for cow ones. The efficiencies of N and P removal were in the range of 7.14%～19.71% and 7.38%～2118%, respectively. The efficiencies of solid-liquid separation were affected by the particle sizes in the manures. The efficiency of the particle removal with the screw separator was higher than that with the manual sieves. It is suggested that separation efficiency could be augmented after technical improvement for screw separator.