DAF process (dissolved air flotation process) is an efficient and fast method for separating solid particles from water and wastewater.
Part of the treated wastewater circulates into the dissolved air floatation pump. Under the condition of pressurized air, the air is supersaturated and dissolved, and then it is mixed with the raw water added with flocculant at the entrance of the air flotation tank. Due to the decrease of pressure, the supersaturated air is released to form tiny bubbles, which quickly adhere to the suspended solids and lift them to the surface of the air flotation tank. As a result, a sludge floating layer that is easy to remove is formed, and the heavier solid matter settles on the bottom of the tank and is also removed.
It is suitable for purifying sewage with high chroma, low dissolved oxygen and many organic impurities. And it is particularly effective for sewage purification with low water temperature and gravity sedimentation. This process is suitable for printing and dyeing, electroplating, tanning, papermaking, chemical, textile, meat processing, oil refining, canned food and other post-production industrial wastewater treatment and production water treatment. It is also suitable for the separation of biological mud film and water in biological treatment.
(1) Under the condition of pressure, the solubility of air is large, and the number of bubbles used for air flotation is large, which can ensure the effect of air flotation;
(2) When the dissolved gas is released by sudden decompression, the bubbles produced are not only fine, uniform in size, large in density, but also stable in floating, with little disturbance to the liquid, so it is especially suitable for solid-liquid separation of loose flocs and fine particles;
(3) The process and equipment are relatively simple, easy to manage and maintain; especially the partial reflux type, the treatment effect is remarkable, stable, and can greatly save energy consumption.