A DeepBed filter may be defined as a granular filter for removal of TSS from secondary treatment effluent using a media depth of at least four feet or 1.2 metres. Coarse media is normally used to encourage deep penetration of solids into the media bed. This allows for longer filtration runtimes. Simultaneous air and water backwashes are used to ensure cleaning of the filters as required. Severn Trent Services has successfully provided gravity, pressure and modular filters and pre-assembled modular gravity deep bed filters to more than 300 installations worldwide.
In addition to TSS removal, TETRA® DeepBed™ and Pressure Filters are frequently specified to reduce BOD levels; achieve metal consents associated with chemical dosing for phosphate removal; improve effluent clarity for UV disinfection; and offer additional protection for works at risk of consent failure.
DeepBed Gravity Filters
The TETRA DeepBed tertiary gravity filtration system from Severn Trent Services is an economical solution for the removal of total suspended solids (TSS). DeepBed filters also provide superior total phosphorus (TP) removal to meet stringent limits below 0.2 mg/l.
The TETRA Deep Bed Filter technology is built on the TETRA T Block and SNAP T Block. As well as offering excellent distribution of backwash air and water, TETRA DeepBed filters deliver high loading capacity and superior capability at handling peak loads. With no nozzles, screens or moving parts, TETRA DeepBed Filters do not clog or wear. The percent of dirty backwash water return is less than 4% (<2% typical) of the plant’s forward flow and the system can be readily expanded into denitrification mode.
DeepBed Pressure Filters
The TETRA DeepBed pressure filters are custom designed to meet the unique criteria of each application. These pressure filters feature filter rates up to 15 gpm/ft2 or 37 m/hr, they are automatic in both filtration and backwashing cycles, with the filter as a stand-alone operation. Flexibility is built into the state-of-the-art control systems to allow operator input to change to manual or automatic modes. TETRA's DeepBed pressure filters combination of nozzle-less filter bottom and spherical monomedia provides special benefits for the industrial market. Systems are efficient in removing oils and grease from influent waters.
Modular DeepBed Filters
The TETRA Modular Deep Bed Filter (MDBF) is a skid-mounted filtration system designed after the TETRA DeepBed technology to be a competitive tertiary filtration plant for secondary effluent from smaller sized wastewater treatment facilities. Consisting of a number of stainless steel filter cells (normally 6, 8, 10 or 12), backwash water pumps, backwash blowers, pipework and control panel, the unit is fully assembled and tested to ensure simple and quick installation and setting to work.