Sludge and gravel treatment
Sludge treatment
Sludge concentration: Concentration is a common solid-liquid separation method, which can be achieved in two ways: flotation where solids float to the top of the mixed liquid, or gravity concentration where solids sink to the bottom of the mixed liquid. The purpose of sludge concentration is to separate excess water from the sludge as much as possible before sludge digestion or dehydration, reduce the sludge volume, and reduce subsequent treatment costs.
Sludge digestion: Sludge contains a variety of organic matter and requires a variety of microorganisms to decompose. Anaerobic digestion and aerobic digestion are common sludge digestion methods. In anaerobic digestion, acid-producing bacteria and methanogens perform hydrolysis and fermentation and methane conversion respectively; aerobic digestion is mostly used for biodegradable sludge, which requires continuous aeration and is not sensitive to environmental conditions.
Sludge dehydration: Mechanical dehydration is a common sludge dehydration method, such as vacuum filtration and centrifugation, which can dispose of sludge in semi-solid form. Commonly used dehydration equipment includes mud separation dehydrator, horizontal spiral unloading sedimentation centrifuge, belt sludge dehydrator, etc.
Sludge drying: Using clean energy such as solar energy and geothermal energy as heat sources for sludge drying, sludge with a water content of more than 80% can be dried into dry materials with a water content of less than 35%, saving electricity and coal, and being environmentally friendly. The entire system is automatically controlled remotely, reducing the cost of sludge treatment and disposal.
During the sewage treatment process, the screen-type water inlet or cyclone grit chamber can remove gravel. If gravel is mixed with sludge and enters the sludge dewatering machine, it will cause equipment wear, so it needs to be effectively removed to protect the equipment, reduce maintenance costs, and ensure the stable operation of the sludge treatment system.