The importance of sewage pre-treatment equipment and the design and operation of pre-treatment have a direct impact on the subsequent process. The specific impact will be explained in detail by Deyuan.
Effect of Pretreatment on Primary Treatment
If the grid design or operation is not reasonable and the ability to intercept grid slag is reduced, a large amount of grid slag will flow through the grid, which will increase the amount of scum in the primary sedimentation tank, increase the amount of scum removal work, and may be hung on the water outlet weir to affect the uniformity of water outlet. Because the organic matter attached to it is easy to corrupt and will increase the stench, affecting the working environment of the water plant. If mechanical mud scraping equipment is used, in addition to increasing its load, sometimes the mud scraping equipment will be damaged due to the presence of certain substances, such as chain type mud scraping machine, the silk will be wound in the chain type, increasing the operation blocking force and damaging the equipment.
There are too many sand and gravel slipping away from the sedimentation tank, which may deposit in the water distribution channel and affect the water distribution uniformity and hydraulic conditions. The sand particles entering the primary sedimentation tank will excessively wear the sludge scraper and shorten its service life. After entering the mud bucket, it will interfere with the normal mud discharge or block the mud discharge pipeline. After entering the mud pump, it will cause excessive wear of the mud pump and reduce its service life.
Influence of Pretreatment on Secondary Treatment
When the grid slag enters the aeration tank, it will wind up on the paddle board of the surface blasting machine or underwater stirring equipment to increase the resistance. Entering the secondary sedimentation tank will increase the scum and affect the uniformity of the effluent by hanging it on the weir. Entering the biofilter will block the water distribution pipe, and entering the biofilter will wind on the turntable. In some treatment plants that do not have a primary sedimentation tank or some sewage crosses the primary sedimentation tank, sand grains will directly enter the aeration tank and deposit at the bottom of the tank, reducing the effective volume and sometimes blocking the micro-porous diffuser. Entering the bio - carousel will also deposit in the pool, reducing the effective volume.
Effect of Pretreatment on Sludge Treatment
What is easy to flow away from the grid is some rags, plastic bags and other sundries. These sundries will wind up on the grid of the thickener after entering the concentration tank, increasing the blocking force and affecting the concentration effect, or wind up on the supernatant outflow barrier, affecting the uniformity of the effluent, and also blocking the sludge discharge pipeline or sludge discharge pump. These sundries enter the digester, and the heat exchanger is easily blocked, and cleaning after blocking is very difficult.
