Many brewing enterprises are troubled by the problem of sludge pressure filtration. For example, the concentration of sludge in juice factory is relatively high, and the dewatering effect of upper pressure filter is not obvious. Because the juice factory needs to cultivate bacteria, and the wastewater contains a lot of bacteria, which are active. But in the sewage treatment, it seems that the effect is not obvious. Clarification of juice is an important process in juice processing. Because the extraction of pulp fragments, pectin, protein and phenolic compounds in fruit juice often cause turbidity and precipitation during storage. Juice factory wastewater is generally acidic, so cationic polyacrylamide can be used. Among them, biological method is widely used because of its high efficiency. Polyacrylamide flocculant can be used in all stages of fungus water treatment. For example, the first stage settling treatment, the second stage settling treatment and thickening, etc., the sludge dewatering stage is the most popular application of pressure filtration.