Maintaining wastewater-treatment sand filters
OwnerDavid A. Pottsinventor
Life of this patent
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Abstract
A downflow sand filter used for treating wastewater which has degraded in function from its original design is at least in part rejuvenated by flowing air downwardly through the bed during time when flow of wastewater is ceased. The low velocity air flow helps dewater the bed and leads to the removal of accumulated organic material which has clogged the pores of the bed. In accord with different embodiments, air flow is alternated with water flow in particular ways, for instance, so the water flow is sufficient to create ponding or is sufficient to maintain moisture content within the bed.
Claims18
In the method of rejuvenating or maintaining the operation of a downflow sand filter used for processing wastewater, wherein water delivered to the top of a sand bed flows by gravity through the bed, the improvement which comprises:
- (a) ceasing the flow of wastewater, where wastewater is the water of a community after the water has been used but prior to being treated and generally prior to the formation of biosludge in the wastewater, onto the top of the bed;
- (b) flowing air downwardly through the bed, while the wastewater flow is ceased, to thereby at least in part dewater the bed and to introduce air into the pore spaces of the bed;
- and (c) resuming the flow of wastewater.
In the method of rejuvenating or maintaining the operation of a downflow sand filter used for processing wastewater, wherein wastewater delivered to the top of a sand bed flows by gravity through the bed, the improvement which comprises:
- (a) flowing air downwardly through the bed;
- (b) ceasing the flow of wastewater onto the top of the bed for a period of time, while continuing the flow of air, to thereby enable the air to at least in part dewater the bed and to enable air to be introduced into the pore spaces of the bed, where wastewater is the water of a community after the water has been used but prior to being treated and generally prior to the formation of biosludge in the wastewater;
- and (c) resuming the flow of wastewater with or without continuing the flow of air.
Dependencies are inferred from the claim text.