Liquid purification or separation – Processes – Treatment by living organism
Reexamination Certificate
1998-05-19
2001-07-24
Barry, Chester T. (Department: 1724)
Liquid purification or separation
Processes
Treatment by living organism
Reexamination Certificate
active
06264838
ABSTRACT:
BACKGROUND OF THE INVENTION
For decades it has been recognized the proper treatment and disposal of human waste is essential to the control of the spread of disease. Pit or trench privies were the first successful methods of isolation of human excrement from insect transmission and pollution of surface waters on rural or sparsely populated land. While high in local odors, the pit privy was efficient in removal of bacteria and viruses. Studies have shown when the raw human waste is in direct contact with the ground water, bacteria or viruses associated with human waste could not be found more than nine feet from the privy wall. It was discovered the ground provided a reliable natural filter for removal of contaminants. Then followed the invention of the septic tank and drain field which allowed the installation of running water to flush away contaminants. A conventional septic tank and drain field disposal system consists of a closed anaerobic holding tank which allows the separation of oils, greases, waxes and soaps by flotation, and the removal of solids by settling. The septic tank has long been recognized as removing only 40 to 50% of the entering waste load, and does little to remove bacteria or viruses. The majority of treatment occurs in the drain field of the septic tank system. In order to provide effective treatment in the drain field, it must be aerobic (with oxygen) to support the microbes which remove the waste from the water. Once a drain field becomes flooded for a relatively short period, the desirable microbes are killed due to a lack of oxygen, and the soil becomes clogged by the waste filtered from the water but not mineralized by the microbes. In lay terms, this is called “septic tank failure”. Septic tanks should have floating matter and settled solids removed every 7 to 10 years to avoid bleed over of those material to the drain field and subsequent drain field clogging. In reality, a septic tank rarely fails to perform its design function. Failures do occur in the drain field when solids, oils, grease, wax or soaps bleed through the septic tank to the drain field. The most common cause of failure of the drain field is flooding caused by hydraulically overloading the drain field beyond its disposal capacity by usage loading or, more often, storm water loading, which results in flooding of the drain field, resulting in the killing of the microbes necessary to provide treatment of the septic tank effluent. Once the microbes have been killed, clogging of the soil occurs rapidly, resulting in septic tank treatment system failure.
Prior art has addressed modification of elements of the septic tank and drain field treatment system, but none have shown a complete synergistic on site wastewater recycle system as divulged herein. The basic difference is the prior art modifications require the use of chemical feeds, routine replacement of elements, or frequent adjustments or cleaning. Control systems for the prior art modifications to a conventional septic tank and drain field system are often quite complex, expensive to construct initially, and require a qualified repairman for repair or adjustment. As examples, Carlson in U.S. Pat. No. 5,738,781 teaches the modification of a septic tank with chambers and granulated charcoal, but does not address further treatment or disposal; Jowett,et.al., in U.S. Pat. No. 5,707,513 teaches the use of foam cells for use with conventional septic tank effluent; Daniels in U.S. Pat. No. 5,645,732 teaches the use of a U shaped filter with fibrous filter material between an inner and outer casing, requiring the polymeric filter medium to be changed periodically; Scott in U.S. Pat. No. 4,824,572 teaches the use of a multi media filter consisting of gravel, limestone, straw or hay planted with reeds, followed by chlorination; Hopcroft in U.S. Pat. No. 4,100,073 teaches the use of a septic tank, a dosing chamber and an enclosed sand filter with disinfection unit; Spratt, et.al. in U.S. Pat. No. 4,826,601 teaches a highly aerobic first cell, followed by anaerobic sedimentation, the third cell is an upwelling flow through a porous anaerobic medium, then to a holding cell, then intermittently through a sand filter/dolomite bed, then to a drain field, with the feeding of alum and methanol optional in the first cell; Justice in U.S. Pat. No. 4,971,690 teaches the use of a septic tank, followed by a chlorine contact chamber (chemical feed), then to a natural filter media drain field below ground, then collection of the waste water effluent by a under drain system, then pumping the water for irrigation purposes; Hadden, et. al., in U.S. Pat. No. 3,933,641 teaches a treatment and recycling system consisting of a septic tank, then perforated splash pan to evenly distribute the effluent over a removable filter, then a second filter, then a holding tank, then chlorinated, then sprayed over the land surface or disposed of by other methods; Benjes, et. al., in U.S. Pat. No. 4,599,167 teaches the construction of an anaerobic digester with packed media with recirculation for the treatment of waste water and the production of methane; Zorich in U.S. Pat. No. 4,895,645 teaches the use of a closed multi chamber multi media biological filter tank between the septic tank and the drain field with a complex control system, but does not teach the plurality of multiple treatment cell types taught by the instant invention nor the synergistic use of plants. The instant invention provides all the synergistic artificial conditions to naturally treat the waste water to produce an effluent more than 99.5% pure while using no chemical feeds, no consumed materials, and no treatment method step which requires frequent maintenance, reliably and dependably. Being simple in design and operation, the instant system is economical to construct, operate, and maintain. The instant system provides the conditions required by nature to provide nearly complete treatment of wastewater, making it suitable to replace existing failed septic tank drain field systems, or to construct the system upon land which does not provide the conditions necessary for ordinary septic tank drain fields to properly function.
SUMMARY OF THE INVENTION
A method of naturally treating sewage is disclosed that is particularly suitable for application for one or a group of residential dwellings on land which will not support a conventional septic tank and drain field system due to adverse soil conditions or elevated ground water table. The system uses no chemicals, is low in maintenance, and is constructed of primarily naturally occurring materials and plants to provide nearly complete removal of Bacteria, Biochemical Oxygen Demand, Suspended Solids, and in periods with warm climates results in little or no effluent to discharge. The system uses a conventional septic tank, a rock/plant filter, a dosing chamber, a shallow horizontal flow pulsed planted aggregate filter, and effluent holding tank. When effluent is produced, it exceeds the quality normally associated with tertiary treatment of domestic wastewater and is therefore suitable for irrigation recycling or other effluent disposal methods.
The following are the objects and advantages of the present invention:
a) to provide a useful on site sewage treatment facility on land with soil or elevated water table unsuitable for a conventional septic tank and drain field disposal system;
b) to provide an on site sewage treatment facility which utilizes natural processes and plants in synergy for sewage treatment;
c) to provide an on site sewage treatment facility which is low maintenance, yet highly reliable;
d) to provide an on site sewage treatment facility which meets or exceeds regulatory department standards and requirements, allowing environmentally responsible usage;
e) to provide an on site sewage treatment facility which makes otherwise unusable land valuable;
f) to provide an on site sewage treatment facility which is relatively inexpensive to build and operate when compared with other standard methods of sewage treatment on land with poor soil attri
Barry Chester T.
Smith , Gambrell & Russell, LLP
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