Abstract: An aerated biological filtration system (10) for treating waste water includes a treatment vessel (11) of elongated configuration which incorporates a circulating filter bed (23) and a static filter bed (24). The circulating filter bed incorporates a particulate material such as granulated activated carbon having a specific gravity in the range of 1.2 to 1.4 and effective size of 0.6 mm to 1.5 mm. The circulating filter bed is disposed above the static filter bed and an aeration system (27) is disposed between the filter beds. The aeration system is arranged to diffuse air through the circulating bed either continuously or intermittently so as to provide oxygen to micro-organisms attaching to the particulate material and to cause slow circulation of that particulate material. The system has particular application for domestic recycling of grey water.

Abstract: An aerated biological filtration system (10) for treating waste water includes a treatment vessel (11) of elongated configuration which incorporates a circulating filter bed (23) and a static filter bed (24). The circulating filter bed incorporate a particulate material such as granulated activated carbon having a specific gravity in the range of 1.2 to 1.4 and effective size of 0.6 mm to 1.5 mm. The circulating filter bed is disposed above the static filter bed and an aeration system (27) is disposed between the filter beds. The aeration system is arranged to diffuse air through the circulating bed either continuously or intermittently so as to provide oxygen to micro-organisms attaching to the particulate material and to cause slow circulation of that particulate material. The system has particular application for domestic recycling of grey water.

Abstract: A fluidized bed waste water treatment reactor which includes a reactor tank containing a particulate media, an array of perforated distribution pipes disposed in a horizontal, parallel array adjacent the bottom of the reactor tank for introducing fluidizing liquid substantially uniformly over the cross-sectional area of the reactor tank. The arrangement is characterised in that an inlet end of each of the distribution pipes extends externally of the reactor tank and the distribution pipes are connected together by a header tank positioned externally of the reactor tank. This arrangement allows access externally of the reactor tank to individual distribution pipes which allows blockages of the pipes to be readily cleared.