The water clarification process in a municipal or industrial sewage treatment plant can be found many times in a treatment process. Typically, there is a primary settlement upstream the biological treatment and a secondary settlement downstream the biological treatment. A primary perfectly operating clarifier allows about 25% – 30% reduction of the polluting load in terms of COD and BOD5 at biological treatment inlet. Even more important are the secondary clarifiers, whose efficiency depends on quantity of total suspended solids in the outlet water. For the dimensioning of the clarifier, besides the surface load and the hydraulic retention time, it is necessary to consider many other important factors such as the retention time of sludge at the sedimentation tank bottom.
SERECO proposes several equipment for the clarification on rectangular tanks, in particular backward and forward travelling bridges with scraping or suction recovery system for the sludge at the bottom, scraping recovery system for the floating substances or chain scrapers in which it is possible to install lamellar package clarification systems interesting for their compactness and efficiency, generally used for the primary or tertiary sedimentation processes.
A complete and integrated solution for aeration and sedimentation can be supplied for biological discontinuous flow treatment system SBR type (Sequencing Batch Reactors), with the supply of extractors by means of which it is possible to extract the supernatant and leave an adequate level of it on the sludge settled at the bottom in order to avoid the presence of sludge during the collection phase.
PRVR – Backward and forward scraper for rectangular clarifier
PRVA – Backward and forward sludge aspirator for rectangular clarifier
RC – Chain scraper
CPL – Lamella clarifier
SGSBR – Floating decanter for sequecing batch reactor