Note: Descriptions are shown in the official language in which they were submitted.
2 ~ S .~. s.
Dry toilet system
The present in~ention relates to a dry toilet system in
accordance with the preamble of claim 1.
The disclosed system is particularly suitable for multi
storey buildings in urban areas; yet the system design
permits its installation in all types of apartment buildings
as well as residences.
In conventional toilet systems the toilet wastes are removed
from the toilet bowl and transferred in the sewer network
using sizable volumes of flushing water. Water from the
sewer network must be processed at waste water treatment
plants prior to its release into a waterway. The quantities
of treated water easily become massive, thereby requiring
large, high-capacity treatment plants in addition to high-
caparlty sewer networks. The construction and maintenance of
such syi~tems imposes high costs on the communities. Further,
the water used for transfer of wastes also contributes to
increased drinklng water consumption.
The removal of wastes causes costs also for the users of the
sy~tem, that is, the tenants or the building cooperative ~ -
shar~holders. The operating costs of the toilet system
derive from the consumption charge of drinking water and the
waste handl~ng charge of sewage water.
~ The removal of toilet wastes by means of water via the sewer
system could as well be replaced by the use of dry toilets.
Prior-art dry tollets have, however, a low capacity which
necessitates their frequent emptying. In multi-storey
~ bui~dings the removal of fermented waste from dry tollets is
cumbersome. Therefore, the prier-art dry toilets are
applicable only to a relatively temporary and cyclic use in,
e.g., camp~r~, boats and recreational buildings.
I~ a muIti-storey apartment house, a dry toilet system has
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earlier been implemented by concentrating the toilets of all
apartments in a single storey and by solvlng the removal of
wastes through compostin~. This constructlon has, however, ..
been neglected, since the remote location of toilets from
the apartments has been considered excessively awkward and
even annoying to the apartment inhabitants.
It is an ob~ect of the present lnvention to achieve such a
dry toilet system capable of replacing the conventional
water-flushed toilet and suitable to be designed into the
construction of individual apartments in a building.
The invention is based on constructing a waste stack in the
building so that said stack is connected via a valve to a
waste collection container. The individual toilets are
connected to the stack via branch pipes and valves. sackflow
of odours to the toilet space is prevented by the use of a
vacuum in the system.
More specifically, the system in accordance with the
invention is characterized by what is stated in the ~.
characterizing part of claim 1. ~'
The invention provides outstanding benefits. .
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With the help of the present system it is possible to
achie~fe a substantial reduction of the waste handling costs
lmposed on the community and the inhabitants of the
premlses. Large volumes of water are not needed for the
trans~er of to:Llet wast~s, as is the case with systems
releasing wastes .ln a sewer network. So, appreciably smaller
volumes of wast:e water are generated, and the exclusion o~
toilet wa~tes ~rom waste water makes waste water treatment
operatlons easier. Then, the sewer network and treatment
plants can be clesigned for smaller loads, and the lesser
total waste wat;er volume reduces envlronmental lmpact.
Because the system can manage without flushing wat er, also
lower consumption of drinking water results f thus reducing
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the enviro~mental loading on surface and ground water
resources. Lower waste water and drinking water consumption
charges resulting from the reduced water consumption also
benefit the premise owners or tenants.
In the system according to the invention, organic wastes
from households are composted, whereby they produce biogas,
and the solid waste remaining can be used for landfill, or
alternatively, when complemented with proper fertilizing
additlves, as a fertilizer. All organic waste generated in
the premises can be removed via the described system, which
reduces the waste handling costs of the premises. The
remainiilg wastes are easier to sort either prior to trans-
portation or at the dump site, which makes the reclaiming of
recyclable m~terial such as glass and metals easier.
A toilet connected to said system in accordance with the
invention, said toilet being located in each separate
apartment, is used in 3 closely similar manner as a
conventional tollet, which makes the use of the toilet easy
to learn and its acceptancelthreshold low. The system is
quieter than a conventional sewer system. Said system is
applicable to all types of buildings, and it can also easily
be constructed in premises to be refurbished.
The invention ~s next examined in detail with the help of
the attached drawings.
Figure 1 shows diagrammatically the system in accordance
with the invention in a multi-storey bullding.
~igure 2 shows a sectional view o~ an embodiment o~ the
toilat seat to be used in the system in accordance with the
lnvention.
~igure 3 shows a sectional view of another embodiment of the
toilat seat.
A ~
The waste removal system comprises a waste stack 1 and
toilet seats 4, which are ~oinecl with connecting branches 5
to the waste stack 1. The lower end of the waste stack has a
control valve 8, via which the waste stack 1 is connected to
a waste collection container 10. The control valve ~ in the
described embodiment is a ball valve. To the waste stack 1,
above the co~trol Yalve 8 J i5 connected the upper end of a
venti~g duct 6. The venting duct 6 is routed to the roof of
the buildin~, and the upper end of the duct ls provided with
a roof exhaust fan 7. The roof exhaust fan 7 provides for a
vacuum applied to the waste stack 1 via the venting duct 6.
With the help of the vacuum, th~ odours from the waste stack ..
are prevented from reaching the tollet space via the toilet ~:
seat 4. The upper end of the waste stack 1 has a venting
valve 2. The passage of the wastes ln the system is -
designated in Fig. 1 by solid arrows, while the passage of : .
th~ air stream sucked by the roof fan 7 is designated by the .
larger outline arrows.
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One possible embodiment of the to.1let seat used in the
descrlbed toilet system is illustrated in Fig. 2. The seat
; comprises a bowl 4~ a seat cover 3, and a check valve 19.
The lower slde of the cover is provided with a bag cassette
12. The cassette 12 is filled with folded bags 20
manufactured from coated paper. The check valve 19 is placed
to the lower part of the bowl ~:, and the seat is connected :
via the valve 19 to the branchlng U~iOrl 5. The stack of the
spindle in the check valve 19 ls provided with a cogwheel
mechanism 16~ 17, and one of the cogwheels has a rod 1~
connected to it. The rod has a return spring 15 adapted. .
about the valve sha~t. The check valve 19 in this embodiment
is a ball valve. When lifted to its upper position, the
cover 3 of the toilet seat reaches the position indicated by
dashed lines.
The seat ~unct:Lons ~s follows: When the tollet is not used,
the cover 3 of the seat is in its closed position. When the
seat is to ba used, the cover 3 1~ lifted to its upper
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positlon. Lifting the cover 3 makes grippers 24 at the sides
of the seat catch the lowermost ba~ 20 in the cassette 12
and hold the bag to the sides of the seat. The bags are
folded to the center of the cassette 12, and when the cover
3 with its cassette 12 is lifted to its upper posltion, the
mld-part of the bag 20 sinks into the bowl 4 of the seat.
1~
~ Next to the lifting of the cover 3, the check valve 12 is
!\ opened by pulling a knob 13 adapted to the rod 1~. The other
end of the rod 14 is attached to a large cogwheel 16. The
motion of the rod 14 rotates the cogwheel 16, which ~urther
rotates the spindle of the check valve 19 by the valve
shaft. The motion of the rod 14 is stopped when the valve is
~ully open, and the rod 14 is latched to its end position,
whereby the valve 19 is also latched open. The valve 19 is
dimensioned so as to make its throat diameter as large, or
preferable, slightly larger than the diameter of the lower
part of the bowl 4 ln the seat. When the valve 19 is opened,
the vacuum in the waste stack 1 sucks the bag 20 down
~0 against the inner surfacé of the bowl ~. The air flow
i~duced by the vacuum further provides an augmented
ventilation of th~ toilet space, thus removing the resulting
odours and preventing the odours of the was~e stack from
reaching the toilet space. The toilet seat is now ready for
2S use.
After toilet use, the sover 3 is closed, whereby the cover 3
pushes the grippers 24 aside, whereby they release allowing
the bag 20 to fall through the valve lg and the connecting
branch 5 to the waste stack 1. Nexk to the closing of the
~over 3, the rod 14 is released ~rom its latched position,
whereby the rod is allowed to fall to lts lower position
under the force imposed by the sprlng 15 and the rod thereby
clo~es the valve 19 by turning it vla the cogwheel mechanism
16, 17. The disposal of household wastes takes place in a
~imilar manner, except that the wastes can be placed ln the
bag ~ven prior to their dropp1ng into the toilet bowl.
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The connecting branches 5 and the waste stack 1 are
dlmensioned so that the diameter of the piping increases at
each branchlng ~oint so as to avoid throttling points of the
piping at which the bag 2Q to be removed could adhere to,
thus making it possible for the wastes packed in the bag to
freely fall via the connecting and stack piping 5, 1 onto
the control valve 8. The control valve 8 is typically held
closed and opened cyclicly under a timer control, then
releasing the waste accumulated to the lower ~nd of the
waste stack 1 to fall lnto the collection contaln~r 10
placed below. The cyclic and generally closed operation of
the control valve 8 is because thereby the odours of the
~aste collected in the container is prevented from escaping
to the surroundings. The valve 8 is controlled to
automatically open at approx. 10...30 min intervals.
ThP roof fan 7 is dimensioned so as to maintain a sufficient
vacuum in the stack 1 even when all toilet seats connected
to the same waste sta~k 1 are used simultaneously. Notwith-
standing the use of the bag, the bowl 4 of the tollet seatmust be cleaned at re~ular lntervals. The bowl can be
cleaned by flushing with water in the same manner as is done
for a conventional toilet seat. The required flushing water
is taken from the faucets of the toilet space. This small
volumQ of water entering the system from flushing does not
lmpair the tollet system functlon; by contrast, water
promotes the further handllng of waste.
The collection containers are removable. The containers are
placed on rails along which they are transferred. A full
container 9 is detached from the control valve 8 and
withdra~n from below it. An empty container 10 is pushed
under the control valve 8 and attach~d to the valve 8. The
next empty cont;ainer 11 to be used remains walting on the
rails. In Fig. 1 the tran~far direction of the containers is
deslgnated by arrows a. The tra~sfer and replacement of the
contain0rs ls handled by a garbage hauling service, and a
tlmer is used l.or the r~placement and the actuation of the
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control valve 8. The containers are transported to the site
of further treatment by trucks equipped with a lift-off
container system. ~ full container 9 is lifted onto a truck
and transported to the site for ~urther treatment, where the
waste collected into the container is transferred to a
larger composting container. The volume of the collection
containers varies according to the tenants in the building.
In multi-storey buildings the appropriate container volume
is approx. 2...5 m3, while in family dwellings a container of
approx. 1 m3 will suffice. The containers have necessary
connections for water discharge or addition. During further
treatment, chemicals are added if necessary to the
container, and if the waste has insufficient moisture
content, also water is added. Oxygen is removed from the
container by suctlon, and the container contents are le~t to
ferment, whereby the metabolism of anaerobic bacteria
produces methane during the fenmentation of the waste. This
methane gas can then be used as fuel in, ~.g., district
heating or thermal power plants. After the addition of
appropriate fertilizing compounds, the composted waste is
finally applicable as a fertilizer or landfill.
Illu~rated in Fig. 3 is another embodiment of the toilet
seat suitable for use in the system in accordance with the
invention. This seat design has not a bag cassette 1~
similar to that used in the toilet seat shown in Fig. 2.
Instead, the spindle 23 of the check valve 19 is shaped to
lncludP a recess into which a bag 22 simila~ to a coffee
filter is placed. Under the upper rim of the bowl 4 of the
seat ls mounted a water pipe 21 with holes. In other
aspects, the seat has ia similar constructlon to that of the
seat shown in l~ig. 2.
During ths use of this seat, the cover 3 i~ opened and the
bag 22 ls placed in the recess of the spindle 23 of the
valve 19. After use of the seat, the valve 19 is opened by
pulling ~rom the knob 13, whereby the waste bag 22 is
automatlcally closed and dumped via the connection branch 5
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a
to the waste stack l. After the closing of the valve, water
is sprinkled to the bowl from the water pipe 21 and the bowl
is flushed clean. The flushing water and urine waste are
routed to the sewer in this embodiment. The use of the
above-described toilet seat is no fashion different from the
use of a conventional toilet seat.
In addition to the exemplifying embodiments described above,
the invention can be implemented in alternative ways. For
instance, the control and check valves 8 and 19 carl have the
form of any suitable valve type such as, e.g., disc or slide
valve. The above-described actuator mechanism 13...17 of the
valve l9 can be replaced by, e.g., an electric motor. In
systems designed for family household use with only a single
tollet seat, the seat is directly connected to the waste
stack 1, thus making the use of connection branches
unnecessary. The bags 20 used in the system can be
manufactured from different grades of paper or degradable
plastics.
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Design example for cost reductions available in different
sizes of Finnish cities:
Deslgn parameters:
The computation is based on treating the charges for raw
water and waste water as costs of the balance sheet, while
the price of produced biogas is considered as income.
Organic wast~ volume produced by a sinyle person 0.767 m3/a
Blogas volume generated by 1 ms of waste 200 m~
Es~imated sale~ market prlce of biogas 0.5 FIM/m3
Raw water cleaning cost 3.37 FIM/m3
Waste water cleaning cost 4.13 FIM/m
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Popula~n Waste voL ~a~ produ~d8io0a3 ~les R~duc~ion in SaVlrl~8 Net profit
lm~ [atO.6ElM/m~l ~abr~on~.[mq [Fl~ [FIM~
_~
20001~;34306~00 153~400 29~200 219~000 3~;!2~400
5000383~~67~0~S0 38~;~000 ~l3~000 ~ 000 933~000
10000~6~701~534~000 ~6Z~000 146~000 1~095~000 1~862~000
25 2Q00016340 3~068~000 1~a3d~000 æg2~000 2~190~000 ~ 20~000
300002301041602~000 2~301~000 438~00Q 3~286~000 E;,586,000
40000~0680~;~136~000 310681000 884~000 413801000 ~i!,448,000
80000383E;0~ZI6 ~01000 3~8g~i~000 ~301000 3142~61000 91330~000
60000460209~204~000 4~6021000 aY6.000 616~01000 11~1~2~000
30 1000063690 IO~Z38~000 ~i~3691000 1~022~000 ~16661000 13~034~000
800006136012~272~000 61136~000 1~165~000 81~601000 14~8g6~000
900006~03013,8081000 619031000 1~314~000 918551000 161~85,000
~00000~6;!01) 1~ 06~000 ~6~0~000 I~g601000 10~960~000 18~620~000
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