废水处理：过滤与电渗析.pptxVIP

废水处理工艺设计及计算;2;Filtration;Surface filtration is gaining in popularity because of the (1)high quality effluent produced, (2)smaller footprint, (3)low backwash rates, (4)reduced maintenance requirements. Surface filtration has been used in several applications including : as a replacement for depth filtration to remove residual suspended solids from secondary effluents, for the removal of suspended solids and algae from stabilization pond effluents, as a pretreatment operation before microfiltration or UV disinfection.;Available Filtration Technologies;The DCMF, marketed under the trademark AquaDisk? by Aqua-Aerobic Systems, consists of cloth filter elements, which have a diamond shaped cross section. The filter elements are cleaned by a vacuum sweep which moves back and forth along the length of the filter, when a predetermined increase in headloss has occurred. Solids that settle to the bottom of the reactor below the filter element are removed;Flow capacity: Up to 400 l/s per filter. Filter opening: 10-100 μm. Filter media is easy to change thanks to new innovative design. Moving backwash system for better cleaning, minimal water use and less wear on filter media. The water to be treated flows by gravity into the filter segments from the centre drum. Solids catch on the inside of the filter panels mounted on the two sides of the disc segments. As the solids catch on the inside of the filter media impeding the flow of water through the disc, the water level inside the discs begin to rise, triggering a level sensor to start the disc to rotate and a backwash cycle begins. High pressure rinse water backs the solids off the filter media and into the solids collection trough.Typically the backwash requires 1-2% of the total flow and filtered water is used.;The Ultrascreen? developed by Nova Water technologies that consists of two continu-ously rotating circular screens of woven stainless steel mesh. The liquid to be filtered is introduced between the two screens at r