Many vacuum cleaners also use HEPA filters as part of their filtration systems. LifeStraw is a brand that manufactures water filtration and purification devices. Filter Press used for filtering liquids by cake filtration mechanism. Reservoir water is treated through chemical coagulation, rapid gravity filtration and disinfection. These filters rely on biological treatment processes for their action rather than physical filtration. Typical treatment processes consist of grates, coagulation, flocculation, sedimentation, granular filtration and disinfection. A HEPA cabin air filtration system was added. Each plant uses a process of pre-chlorination, aeration, filtration, and chlorine residual. Centrifugation may be a preliminary step to reduce sludge volume for subsequent filtration or evaporation. The filtrate includes water, small molecules, and ions that easily pass through the filtration membrane. Combined biological and mechanical aquarium filtration systems are common. Its spherical shape makes it preferred for fluidized bed applications such as water filtration. Garnet sand is also used for water filtration media. The water is filtered at Bhandup, which is Asia's largest water filtration plant. There were also problems with increasing water filtration through dam concrete.