Multi-unit flush system having carbon adsorber column in calcium carbonate bed

A flushing water-circulation type flush system to purify living water or sewage into clean water. Water discharged from a toilet is directed successively to a filter bed unit having filter material therein, to an aeration unit, to a settling unit where solids are settled out, to a pH regulation unit containing an adsorber column having activated carbon therein, the pH unit also containing a source of calcium carbonate, with the adsorber extending therethrough. Outflow from the adsorber is passed through a sterilizer unit to a flushing water unit which serves as a source for supplying flushing water to a water reservoir for the toilet.

FIELD OF THE INVENTION 
The present invention relates to a flushing water-circulation type flush 
system which can purify living waste water or sewage into clean water 
recyclable as flushing water, making it possible to set up flush toilets 
assuring a comfortable life as in city, as well as in agricultural areas 
where sewerage systems are not provided. 
STATEMENT OF THE PRIOR ART 
Heretofore, a number of proposals have been made of such a system, as 
represented by a purification and circulation type flush system disclosed 
in Japanese Utility Model Publication No. 5106/1987. 
According to this system, sewage discharged from a toilet stool is purified 
by passing it successively through a filth settling and separating tank, a 
plurality of aerators, a washing tank and a cylindrical sterilizer, which 
are all buried in the ground. Then, after the remaining suspended matters 
have been filtered out, the sewage under treatment is circulated through a 
plurality of filters set up on the ground by means of a driving pump for 
purification, thereby obtaining purified water. As occasion arises, a part 
of the purified water is supplied to a water tank by the manipulation of a 
lever provided with the water tank so as to recycle it as flushing water. 
Although the above system is by and large effective for the purification of 
sewage, it has the following disadvantages. 
First of all, when the amount of load on the unit in which sewage flows is 
smaller than the amount of load preset for it, inorganic and organic 
nitrogen in the sewage is sufficiently oxidized by nitrite and 
nitrification bacteria living in the aeration tanks, so that increased 
hydrogen ions are generated, while the pH of the sewage during treatment 
is reduced to below 3.8. In some cases, this may lead to a remarkable 
lowering of the purification capability of the aeration tanks. 
It is desired that the pH of the aeration tanks be maintained at a range of 
5.8 to 8.6. However, since the circulation mechanism of this system 
includes no pH regulator, this system may possibly work in a state where 
the aeration tanks do not properly fulfill their own purification 
function. It is therefore difficult to obtain flushing water having 
stabilized properties. 
As the pH value of the sewage under treatment is lowered with the progress 
of the oxidation thereof, the disintegration of suspended matters takes 
place and the supernatant of the sewage under treatment in a settling tank 
is suspended. Since the filtration of such supernatant causes clogging of 
the filter used for the purpose, the filter is required to be frequently 
checked and cleaned so as to enable it to fulfill its necessary function. 
Thus, this system is troublesome to maintain and control. 
Another disadvantage is that the working cost per system is increased, 
because a considerably high power cost is needed to circulte the sewage 
under treatment from a pump chamber buried in the ground to a plurality of 
filters set up on the ground by constant operation of the pump. 
SUMMARY OF THE INVENTION 
The flushing water-circulation type flush system according to the present 
invention includes an anaerobic filter-bed unit and a contact aeration 
unit and, hence, ensures the digestion of organic filth matters contained 
in sewage. The present system can work in a constantly stable state, even 
when there is a variation in the amount of load on the unit in which 
sewage flows, because the sewage under treatment is maintained by the pH 
regulation unit at a pH value at which the anaerobic filter-bed and 
contact aeration units function properly. Thus, it is possible to obtain 
flushing water having stabilized properties. 
Since the pH value of the sewage under treatment is always maintained in a 
proper range, it is assumed that suspended matters do to appreciably 
disintegrate and settle down as sludge, eliminating the possibility of the 
occurrence of a suspension phenomenon in the sewage under treatment in the 
units subsequent to the aeration unit and, hence, eliminate an accident 
which may impede the operation of the system. Thus, the present invention 
is easy to maintain and control. 
A pump in the water supply arrangement is actuated by the manipulation of a 
lever, only when occasion arises, and a main portion of the power is 
consumed by an air blower of a constantly working air supply unit. Thus, 
the working cost of the system is relatively low. 
A main object of the present invention is to provide a flushing 
water-circulartion type flush system which satisfactorily solves the 
problems mentioned above by the provision of a system of greatly increased 
capability in which a pH regulation unit is provided to regulate the pH of 
an aeration unit to around 7, and a mixing unit and a back-flushing unit 
are provided in the aeration and pH regulation units, and which can reduce 
the power cost.

DETAILED DESCRIPTION OF THE INVENTION 
The present invention will now be explained in greater detail with 
reference to the embodiment shown in FIGS. 1 and 2. A sewage disposal 
system 1 comprises an anaerobic filter-bed unit 2, a contact aeration unit 
3, a settling unit 4, a pH regulation unit 5, a circulation unit 6 and a 
flushing water unit 7 which are juxtaposed in series in a tank 8, and is 
located below a toilet stool 9. The tank 8 may be the ground. 
The anaerobic filter-bed unit 2 is between an end wall of tank 8 and 
separator wall board has in its upper region a discharge port 11 of a 
sewage pipe 10 connected to the toilet stool 9, which is disposed above 
it; a layer of filter-bed material 12 such as a cross type 
corrugated-sheet filler material is floatingly located approximately at 
the mid-depth of filter-bed unit 20 and has a volume of about 50% thereof. 
Two vertical delivery pipes 15 are located at the right-hand end of 
filter-bed unit 2 and are spaced from layer 12. Pipes 15 are open at their 
lower ends to the region below the lowermost layer of the filter-bed 
material 12 and include an outlet port 14 in communication with the 
adjacent contact aeration unit 3 through partition wall 13 which is a 
common wall to filter-bed unit 2 and aeration unit 3. Outlet port 14 is a 
short distance below the top of tank 8. 
The contact aeration unit 3 is between partition walls 13 and 20, and 
communicates with the anaerobic filter-bed unit 2 through the outlet port 
14; it includes a layer of contacting material 16 in the form of, e.g., a 
corrugated sheet, which is floatingly located approximately at the 
mid-depth of aeration unit 3 and has a volume of about 55% thereof. A 
central circulation pipe 18 extends vertically through the contact 
material 16, into the bottom of which air is blown to suck the sewage from 
near the bottom 17 of the aeration unit 3 and discharge it from its upper 
end, thereby circulating the sewage above and below the contact material 
16. As shown in FIG. 3, a rectangular air diffusion pipe 19 is disposed in 
the vicinity of the underside of the contact material 16 and is provided 
with a plurality of air vent holes at suitable intervals, said air 
diffusion pipe 19 blowing air into the aeration unit 3, thereby forcefully 
removing biologicl film which may be formed on the surface of the contact 
material 16 by the oxidative digestion of filth matters contained in the 
sewage, when such film thickens to such a degree that the contact material 
16 is clogged. 
The settling unit 4, between partition walls 20 and 22, communicates with 
the contact aeration unit 3 through partition wall 20 which is open near 
the bottom 17 of the contact aeration unit 3. Settling unit 4 has a bottom 
21 extending from partition wall 22, inclined so that settling sludge is 
easily moved toward the bottom 17 of the contact aeration unit 3. 
Partition wall 22 includes a port 23 for communication with the adjacent 
pH regulation unit 5, and located a short distance from the top of tank 8. 
The pH regulation unit 5 is between partition walls 22 and 22a, and 
communicates with the settling unit 4 via the inlet port 23 in and near 
the tip of partition wall 22. A layer of pH regulation material 24 is 
located approximately at the mid-depth of unit 5 and comprises a meshed 
bag filled with suitably pulverized oyster-shells; a cylindrical absorber 
27 for the decoloration, etc. of the sewage under treatment, which is 
provided with suction ports 25 in the vicinity of the level of the sewage 
under treatment, has an outflow pipe 26 connected to it near its lower 
end. Outflow pipe 26 extends upwardly, then through partition wall 22a 
into the upper portion of the adjacent circulation unit 6. Adsorber is 
filled with activated carbon 27A in its lower part and extends vertically 
through the pH regulation material 24. A cylindrical draft pipe 28 extends 
vertically through the pH regulation material 24, laterally of adsorber 27 
as shown in FIG. 2, for circulating the sewage above and below the pH 
regulation material 24 on the same principle as the circulation pipe 18. 
Draft pipe 28, now shown in FIG. 1 for purpose of clarity, is provided 
with air blown through air pipe 19. A sludge return conduit 30 extends 
through the pH regulation material 24 for sucking up the sludge which has 
been deposited on bottom 29 of the pH regulation unit 5 and returns it to 
the anaerobic filter-bed unit 2. 
The circulation unit 6 is spaced at the partition walls 22a, and the 
outflow pipe 26 of the adsorber 27 discharges adjacent circulation unit 6, 
circulates th sewage under treatment to the pH regulation unit 5 so as to 
achieve complete pH regulation and decoloration. The circulation unit 6 is 
provided with a vertical air lift circulator 31 between partition walls 
22a and 22b, working on the same principle as the draft pipe 28. 
The flushing water unit 7 is adjacent an end wall of tank 8 and has a 
sterilizer 33 fixedly provided on the side of the circulation unit 6 in 
such a manner that an antiseptic contacts the sewage flowing through the 
sterilizer 33, passing through a chamber therein for holding an antiseptic 
cylinder 32 filled with said antiseptic. 
The sewage disposal system 1 also includes, as shown in FIG. 2, an air 
supply conduit 36 having an air blower 35 for feeding the necessary air to 
the circulation pipe 18, air diffusion pipe 19, draft pipe 28, sludge 
return conduit 30 and air lift circulator 31 by way of a pipe 34 having 
valves at the required sites; and a water supply system 42 having a water 
reservoir 41 located above the toilet stool 9 and connected thereto by way 
of a water pipe 37, said reservoir 41 including a lever 38 which is 
manipulated to actuate a pump 40 connected to a pipe 39 joined to the 
flushing water unit 7 for the circulation of flushing water. It is noted 
that the pipe 39 of the water supply system 42 is connected to the 
back-flushing pipe 44 for supplying flushing water to the bottom of the 
adsorber 27 through a valve 43, which is adapted to be opened so as to 
actuate the pump 40 and closed so as to stop the pump 40. 
The flush system according to the present invention is constructed as above 
described. Reference will now be made to the process of the purification 
and circulation of sewage. 
As the lever 38 is manipulated, the flushing water stored in the water 
reservoir 41 is fed to the toilet stool 9 by way of the water pipe 37 for 
flushing it, whence it flows as sewage into the anaerobic filter-bed unit 
2 through the discharge port 11 of the sewage pipe 10. In the anaerobic 
filter-bed unit 2, the sewage passes downwardly through the filter-bed 
material 12, while organic matters contained therein are anaerobically 
digested and deposited/purified by the action of microbes under permeable 
and absolute anaerobic conditions. It is understood that a part of 
undigested inorganic and organic matters settles down and accumulates as 
sludge on the bottom of tank 8, and some solid matters float on the 
sewage. 
The sewage, which has been digested and purified in the anaerobic 
filter-bed unit 2, then flows from the bottom of the filter-bed unit 2 
through both of the delivery pipes 15 and the outlet port 14 of each into 
the adjacent contact aeration unit 3. In the contact aeration unit 3, the 
sewage passes downwardly through the contact material 16, during which 
filth matters contained therein such as organic matters come in repeated 
contact with an aerobic biological film growing on the contact material 16 
under aerobic conditions and, in the meantime, they are adsorded thereto 
and undergo oxidative digestion thereon. Air is blown from the pipe 48 
which is connected to the pipe 34 of the air supply conduit 36 into the 
lower portion of the circulation pipe 18, whereby the sewage is sucked up 
from around the lower end of the circulation pipe 18 and forced up 
together with the air, and is discharged from the upper end thereof. In 
this manner, the sewage below the contact material 16 is circulated to 
promote the oxidative digestion, while the air is supplied to create the 
aerobic conditions. It is understood that when the biological film growing 
on the contact material 16 thickens to such a degree that the contact 
material 16 is clogged with the progress of the oxidative digestion of 
sewage, the valve 47 is opened to feed air from the pipe 48 connected by 
the pipe 34 to the air diffusion pipe 19, from which the air is supplied 
in the form of bubbles which give vibrations to the contact material 16 
and the surrounding sewage, thereby forcefully peeling off the thickened 
biological film. 
The thus peeled-off sludge is entrained in a stirring stream produced by 
bubbles, goes up, and travels to the anaerobic filter-bed unit 2 by way of 
the delivery pipe 15, settling on the bottom of it. The sewage under 
treatment in the contact aeration unit 3 is transferred from its lower 
portion to the settling unit 4 in which, during residence, the suspended 
matters in that sewage settle down and separate out, and the thus purified 
supernatant water overflows from the inlet port 23 into the pH regulation 
unit 5. 
When the sewage under treatment is sufficiently oxidized in the contact 
aeration unit 3, the inorganic and organic nitrogen contained therein is 
oxidized to nitric and nitrous nitrogen by nitrification bacteria, which 
produce hydrogen ions acting to lower pH, bringing the sewage to an acidic 
region (at below pH 5.8 in an extreme case). In the pH regulation unit 5, 
therefore, the sewage under treatment is allowed to react with calcium 
carbonate that is a main component of the oyster-shells of the pH 
regulator unit 5 whereby it is regulated to a pH range of 7 to 8 in which 
the anaerobic filter-bed unit 2 and contact aeration unit 3 function 
properly and, at the same time, the rest of suspended matters contained in 
the sewage under treatment is adsorbed onto the surfaces of the 
oyster-shells, giving the sewage under treatment an extremely reduced 
amount of suspended matters. 
Subsequently, the sewage under treatment having its pH value regulated 
flows from the suction ports 25 into the adsorber 27, and passes 
downwardly through the activated carbon 27A which is inside it, during 
which the organic matters remaining in the sewage inder treatment are 
desorbed onto activated carbon, so that it becomes almost colorless and 
transparent. Then, the sewage under treatment flows through the outflow 
pipe 26 into the adjacent circulation unit 6. 
It is noted that effective adjustment of pH values in the pH regulation 
unit 5 is achievable by blowing air from the pipe 49 into the lower end of 
the draft pipe 28 and circulating the sewage under treatment above and 
below the pH regulation material 24 on the same principle as the 
circulation pipe 18, for the purpose of mixing. Air is also blown from the 
pipe 50 into the sludge return conduit 30 to return the sludge settled on 
the bottom to the anaerobic filter-bed unit 2 on the same principle as the 
circulation and draft pipes 18 and 28. If the adsorber 27 is used over an 
extended period of time, slight amount of suspended substances contained 
in the sewage under treatment is then absorbed and accummulated thereon so 
that the filtration resistance is increased enough to bring the working 
level up to the substantially same level as the settling unit 4. In that 
case, the valve 43 of the back-flushing pipe 44 connected to of the pipe 
39 of the water supply system 42 is used to actuate the pump 40 for 
pressurizing the flushing water, which is then used to flush the activated 
carbon layer from below, thereby recovering the filtering capability. 
In the circulation unit 6 into which the sewage under treatment flows by 
way of the outflow pipe 26, some of the sewage, now substantially 
colorless and transparent, is circulated back to the pH regulation unit 5 
by the air lift circulator 31 so as to extend the time of contact thereof 
with the pH regulation material 24 in the pH regulation unit 5 and 
activated carbon in the adsorber 27. 
The sewage under treatment overflows from the upper portion of the 
circulation unit 6, and flows into the flushing water unit 7 through the 
sterilzer 33 fixed to the side thereof. While passing through the 
sterilizer 33, the sewage under treatment is sterilized, because bacteria 
such as Escherichia coli living therein are killed by chlorine leaching 
out of a chlorine agent filled in the antiseptic cylinder 32. 
When the lever 38 of the water reservoir 41 is manipulated to flush the 
toilet stool 9, the pump 40 of the water supply system 42 is actuated to 
transfer the flushing water stored in the flushing water unit 7 to the 
water reservoir 41, and the pump 40 is automatically stopped upon the 
water reservoir 41 being filled with a predetermined amount of water. 
It is noted that in order to facilitate internal checking, repairing and 
cleaning of the sewage disposal system 1, as shown in FIG. 2, manholes are 
provided in the upper portions of the tank 8 above the anaerobic 
filter-bed unit 2, the delivery pipe 15, the contact aeration and settling 
units 3 and 4, and the pH regulation and flushing water units 5 and 7. 
In the one specific embodiment as described above, the delivery pipes 15 of 
the anaerobic filter-bed unit 2 are provided at two location with a 
suitable space between them. However, such an arrangement may be varied 
depending upon the amount of sewage to be treated. If the amount of sewage 
and the volume of the filter-bed unit 5 are small, then only a single 
delivery pipe 15 may be provided. If the amount of sewage is large, on the 
contrary, then multiple delivery pipes 15 may be provided. 
The air diffusion pipe 19 of the contact aeration unit 3 as shown in at 
rectangular configuration below the bottom of the contact material 16. It 
is understood, however, that the present invention need not be limited to 
the rectangular configuration, if the air bubbles issuing therefrom strike 
over the entire surface of the contact material 15. It is also understood 
that although oyster-shells are used for the pH regulation material 24 
disposed in the pH regulation unit 5, other materials may be employed, 
provided that they contain a neutralizer such as calcium carbonate. 
While the pH regulation unit 5 has been described to include the draft pipe 
28, the draft pipe 28 may be omitted when a material less resistant to the 
passage of the sewage under treatment is employed for the pH regulation 
material 24. In that case, the pH regulation unit 5 may without the 
circulation provided by the draft pipe 28 function. 
The system according to the present invention digests organic filth matters 
contained in sewage in the two stages of the anaerobic filter-bed unit and 
the contact aeration unit, and works in a constantly stable state, even 
when there is a variation in the amount of load applied on the unit in 
which the sewage flows, because a pH value at which both the above units 
function properly is maintained by the pH regulation unit. It is thus 
possible to obtain flushing water having stabilized properties and, hence, 
completely meet the demand of users. 
Since the pH value of the sewage under treatment is always maintained in a 
proper range, it is assured that suspended matters do not appreciably 
disintegrate and settle down as sludge, eliminating the possibility of 
occurrence of a suspension phenomenon in the sewage under treatment in the 
units subsequent to the aeration unit and, hence, an accident which may 
impede the operation of the system. Thus, the present system is very easy 
to maintain and control. 
Since only the air blower of the air supply unit works constantly, the 
power consumed by the overall system is so reduced and the operating cost 
is very low.