Abstract: A dredge having an auger, a pump and a screen box is inserted into the waste pit of an animal holding structure. The rotatable auger bites into a local portion of a body of sludge on the bottom of the waste pit and puts such local sludge portion into a liquid suspension that can be pumped by the pump through the screen box and then out of the waste pit to an exterior of the structure. The screen box has a basket shaped filter screen that retains relatively large foreign debris as a spot close to the pump. The sludge pumped out of the waste pit is dewatered by a shaker table to convert the liquid suspension into a particulate material and into a liquid. The particulate material comprises the nutrient rich sludge previously on the bottom of the waste pit and can be reused as fertilizer.