Filter pit unit
Treatment > Filter pit unit
The biological filter pit septic tank (decanter/digester) system is suitable for domestic-type waste-water.
The system meets current Spanish regulations on dumping "Reglamento del Dominio público Hidráulico" [Regulation of the public water domain], Royal Decree 849/1986.
The filter pit units are sized for an intake of 200 l/p.e. and day with a 24-hour retention time. Performance figures for this treatment system are as follows:
- BOD5 REDUCTION 80%
- SS REDUCTION 90%
The waste water entering the treatment plant passes first through the septic tank (decanter/digester) which performs the primary sedimentation and digests the sludge, where the anaerobic bacteria degrade the organic matter, breaking down the solids. The clear water passes through the biofilter by way of pipes that distribute the clear water onto the filtering material, where the aerobic bacteria keep purifying the water of the organic remains and leave it in optimum conditions for discharging.