Liquid purification or separation – With alarm – indicator – register – recorder – signal or... – Material level or thickness responsive
Reexamination Certificate
2000-02-07
2001-10-30
Drodge, Joseph W. (Department: 1723)
Liquid purification or separation
With alarm, indicator, register, recorder, signal or...
Material level or thickness responsive
C417S040000, C417S002000, C210S104000, C210S109000, C210S123000, C210S170050, C210S138000, C210S532200
Reexamination Certificate
active
06309539
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a filtration and subsurface distribution system and, more particularly, to a filtration and subsurface distribution system having a splitting device for containing and discharging filtered effluent (e.g., filtrate) into an on-site drain or dosing absorption field without mixing with unfiltered effluent.
2. Background Description
In the absence of conventional public wastewater disposal and treatment systems, it is not uncommon for residential and small businesses to use on-site waste water management systems. Typically, these wastewater management systems include a septic tank, and under certain conditions may additionally include a recirculating pump tank and filter.
In one such conventional system, wastewater flows into and out of the septic tank via baffled pipes which slow the flow of water and prevent sewage from flowing directly through the septic tank. In the septic tank, solids are settled into the bottom while lighter particles including grease and foam float to the surface and form a layer of scum. The solid material in the septic tank is then broken down via a bacterial action.
In systems without a recirculating pump tank or a filter, the wastewater then flows from the septic tank into a distribution box so that the wastewater can be spread evenly into porous pipes arrayed in an absorption field (e.g., on-site drain or dosing field). The quality of the resulting absorption treatment and filtration of the effluent will depend on the characteristics of the soil and the site. These characteristics may include soil permeability, drainage, slope, and depth to limiting conditions such as groundwater or bedrock. Thus, poor soil conditions will negatively impact on the resulting quality and absorption of the septic effluent.
In cases where the absorption of the effluent in the on-site absorption drain or dosing field is not sufficient to adequately treat the septic effluent, recirculating pump tanks (also referred to as mix chambers) as well as filters may be utilized to further treat the effluents. In these wastewater management systems, the septic effluent is discharged into the recirculating pump tank which includes a single chamber and a recirculating pump. In use, the recirculating pump periodically pumps the septic effluent in appropriate doses from the recirculating pump tank to the filter for filtering of the effluent. During the filtering process, the effluent is filtered so that solid particles will be removed from the effluent and may be further treated by way of an aerobic process which removes further contaminants therefrom. After the effluent is distributed over the filter, the filtrate (e.g., filtered effluent) is collected and directed back through a ratio box to the recirculating pump tank and the drain field.
It is noted, however, that the filtrate returning to the recirculating pump tank is then mixed with unfiltered septic effluent in the recirculating pump tank. This, of course, contaminates the filtrate such that the contaminated filtrate must again be refiltered via the filter. It is further noted that by using this type of system the filter is not dosed with effluent during low flow periods. This allows for long filter rest periods which then detracts from the quality of effluent being discharged from the system. This is mainly due to lack of biological activity within the filter during resting periods and immediately after restart.
Although ratio boxes are widely used in the field of wastewater management systems, another method of treating the effluent is to first discharge the septic effluent from the recirculating pump tank into the filter and thereafter permit the filtrate to flow directly back into the recirculating pump tank. However, in these wastewater management systems the final discharge of the effluent is determined by the elevation of the pumping station such that the filtrate may be mixed with the septic effluent, at times. As an improvement over wastewater management systems that use ratio boxes, these systems periodically dose the filter on a continuous basis thereby providing enhanced effluent quality with low maintenance costs. Again, the enhanced effluent quality is mainly due to the fact that the filter is not rested for long periods thus ensuring enhanced biological activity of the filter.
What is thus needed is a wastewater management system that does not mix septic effluent with the filtered filtrate prior to discharging the filtrate. This system would thus ensure that only filtrate is discharged into the absorption drain field and that only septic effluent is being filtered by the filter. Such a wastewater management system would also be capable of controlling the effluent flow into the filter (e.g., dose the filter) and filtrate into the absorption drain field such that the filter and the absorption drain field are utilized in an efficient manner thereby providing enhanced effluent quality with low maintenance costs.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a filtration and subsurface distribution system having a vaulted splitting device (e.g., dosing vault) associated with a recirculating pump tank.
It is a further object of the present invention to provide a filtration and subsurface distribution system that is controlled by an integrated control unit.
It is also a further object of the present invention to provide a filtration and subsurface distribution system that prevents mixing of septic effluent with filtrate.
It is still another object of the present invention to provide a filtration and subsurface distribution system having a separate filtrate pump for pumping only filtrate into an absorption drain field.
It is also another object of the present invention to provide a filtration and subsurface distribution system having an alarm system to alert a user when the effluent in the recirculating pump tank exceeds a certain level.
It is still also another object of the present invention to provide a filtration and subsurface distribution system having an alarm system to alert a user to a failure of a sand filter pump or a dosing pump.
It is also still another object of the present invention to provide a control unit having a dose timer for efficiently treating and disposing septic effluent on a time dose basis.
According to the invention, there is provided a septic tank for receiving effluent from a household or other building. The overflow of the septic tank flows into a recirculating pump tank which includes a dosing vault separated from the effluent flowing into the recirculating pump tank. The recirculating pump tank houses a sand filter pump and the dosing vault houses a dosing pump. The dosing vault and the dosing pump may be housed outside and remote from the recirculating pump tank which ensures that effluent will not be mixed within the dosing vault.
The sand filter pump doses a sand filter with the septic effluent via a feed line. The effluent is then filtered by the sand filter and returned to the dosing vault via a filtrate return. When the filtrate reaches the dosing vault it is isolated from the effluent in the recirculating pump tank. The filtrate overflows the dosing vault into the septic tank. When the filtrate reaches a certain predetermined level within the dosing vault and the recirculating tank, the dosing pump is enabled and turned “on”. In this manner, the filtrate is dosed or dripped into a drain absorption field without mixing with the septic effluent.
The filtration and subsurface distribution system also includes several floats for controlling (preferably in combination with a control unit) the sand filter pump and the dosing pump. A first float in the recirculating pump tank allows the control unit to run the sand filter pump when the effluent raises the first float above a normal position and “disables” the sand filter pump when the effluent falls below the level of the first float. A second float in the recirculating pump tank and positioned above the
American Manufacturing Company, Inc.
Cecil Terry K.
Drodge Joseph W.
McGuireWoods LLP
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