| Sand is the bedding material of choice for dairy freestall barns. Although sand possesses many favorable characteristics from a cow health standpoint, it is incompatible with long-term manure storage systems. Separating sand bedding prior to long-term storage would allow the use of conventional manure handling and disposal systems such as irrigation, tanker spreading, and sub-surface injection. An assortment of liquid/solid separation techniques common to wastewater treatment operations as well as the dairy, mining, and petroleum refining industries were applied to sand-laden dairy manure. Separation techniques considered include: (i) screening, (ii) sedimentation, (iii) the hydrocyclone, (iv) dissolved air flotation, and (v) the belt filter press with polymer conditioning. A sand separator, the batch aerated grit chamber(BAGC), was developed based on the separation techniques previously considered. The BAGC is capable of yielding a dilute manure fraction that can be pumped, stored, and land applied via conventional manure handling techniques, as well as a sand fraction clean enough that it may be reused as bedding. |
