sewerage facilities, those where pollution to public water such as rivers, lakes, the sea,water for farming, etc. is a concern or mountainous areas with limited water, so some ofthese areas still rely on primitive pit toilets or simple ﬂushing with a cup of water. Double
Clean is a non-discharge (closed-loop) system that adds tertiary to quinary cleaning toconventional septic tank treatment and after-treatment of toilet water (BOD 13,000ppm), purifying it to BOD 5 ppm or less and recycling it to be used for ﬂushing.

Portable/Above-Ground Double CleanThis type is installed in places where excavation is diﬃcult (rocky areas, mountains,summits, etc.). It is protected against external pressure and low temperatures and fullycompatible with exterior decoration and transport methods. Potential uses include
portable toilets at mountain huts, river terraces, above-ground construction sites andnational parks and installation is the only work required.

Variant Double Clean
This product was designed by combining our system with conventional household

septic tank expertise to process household wastewater into reusable water. In addition
to toilet water, this recycled water can be used to water ﬂowers, trees and gardens,

prevent ﬁres and as an emergency water source. It recycles this resource without waste.
Double Clean is a rigorous treatment system (BOD 5 ppm or less) that recycles wastewateras toilet water without discharge, allowing usage of ﬂush toilets in any location. It
carefully protects our living environments and natural habitats from sewage pollution.

Double Clean
Features
Saves energy

Reusing the treated water
makes daily water supply
unnecessary. Furthermore,collection is only required
about once a year.

BOD 5 ppm or less

Double Clean adds bio(anaerobic/aerobic properties)
to toilet water, puriﬁes it further
in an aeration chamber and,with a convection chamber andadsorption unit, produces
reusable water with BOD 5
ppm or less.

Secures water sourcesand environments
A ﬂush toilet uses about 50
liters of water per person perday. Reusing this water protects
water resources and notdischarging it protects theenvironment.

Non-discharge

Since the treated water is reused
without being discharged, ﬂush
toilets can be installed even inplaces with no sewers or outputs.

Commercial use

We oﬀer a variety of products
ranging from household (small)to commercial (large) use.

Double Clean is a non-discharge wastewater recycling system

Flush toilets cannot be installed in areas such as those with no septic tank output or

It can ﬂush toilets even in places with no sewer or other output.

Underground Double Clean

Clean

The distinguishing feature of this toilet is that it puriﬁes wastewater

Oyster shells for water puriﬁcation

into reusable water in a closed loop (without discharge), meaning that

Oyster shells are incredible effective at purifying water, removing 90% or more of BOD, around

it protects water resources and is environmentally friendly.

90% of COD and 95% or more of SS. Coliform bacteria in the inﬂowing water is adsorbed onto
the surface of the oyster shells, greatly improving hygiene, and it is this property of oyster shells

Clean (freshly supplied) water is used for hand-washing (and can also
be reused.)

that Double Clean utilizes to produce recycled water with BOD 5 ppm.

*Miscellaneous wastewater is processed separately.

BOD 260 mg/LReused(recycled)*BOD (biochemical oxygen demand) is the amountof oxygen in the water used by bacteria when
breaking down organic material.

SewageFilterLarge clumps sink to the bottom.

Secondary treatment tank

Tertiary treatment tank

●Fish can be caught and eaten from river water at BOD 5 ppm or less.

*Aerobic bacteria in the inﬂowing wastewater are
easily absorbed by the oyster shell surfaces

Double Clean Wastewater Recycling Equipment●Places where below ground is impossible ●Rocky areas and other places with limiting or bad conditions●Rest stops on hiking trails (mountain roads) ●Public toilets on river terraces (movable at a momentʼs notice if water rises)●Park campgrounds in the spring, summer and fall, then moved to ski resorts in the winter

It can be used for portable toilets on construction sites ‒ regardless of the length of the term,
it can be installed in locations with no discharge outputs.

●When installed in a place where extraction treatment by a vacuum truck is not possible, the settling tank can be detached andtransported away for processing.
●Treatment equipment can be prepared for a range of applications from a single person to various tank needs.

Occupying only about 3.3 m ofhousehold space, our products
can be installed not only during
new construction but also
expansion and remodeling.
2Air

Quinary treatment tank

Because oyster shells are calcite,
they are kept to a pH value of 7.

Fine contaminants arebroken down further.

Activatedcarbon cylinder

Circulation pump tank
Activated carbon removes
color and smell.

*pH values lower than 7 (neutral) are more acidic;
those higher are more alkaline.

Speciﬁcations■ Recycled water for business use
3m /day (processing capacity)■ Speciﬁcations(for WK-5, 50 Hz)
Capacity/materialFirst tank
Capacity

Material

We can prepare an environmentally-friendly generator for places without electricity.
The generator engine uses natural gas/LPG. Solar and wind power can also be added.

●High altitude installations can be done by helicopter.
●The exterior walls of the above-ground Double Clean are made of natural wood but can be designed according to your artistic
preferences. Designs that match the natural environment of the site are also possible. In addition, speciﬁcations according to the local
region can be ﬁnished by local industry.

Oyster shells

Quaternary treatment tankContaminants are mixed and broken down.
Microorganisms break down contaminants●River water at BOD 3 ppm or less is used for tap water.

*Graywater indicates that the water quality is
between that of clean water and sewage.

FilterOyster shells

Circulation pumpfor activatedcarbon cylinder

BOD 5 ppm or lessBlowerAir

Settling tank

Graywater

Pump to supply
water to toilet

The portable version can be installed in the following locations:

The treated water is rigorously
puriﬁed (BOD 5 ppm or less)with no trace of smell or color,
keeping the ﬂush toilet clean
and fresh.

Expansion/remodeling

Double Clean Wastewater Recycling System Diagram (Underground/Portable)

Equipment

Equipment
speciﬁcations
32.5ｍ

3

Type

Processing capacity

WK-15

0.95ｍ ／day
33

Second tank

2.5ｍ

WK-20

1.10ｍ ／day

Main body

FRP

WK-25

1.25ｍ ／day

ManholePP composite

WK-30

1.50ｍ ／day

Main body piping

VP

WK-40

2.00ｍ ／day

WK-50

32.50ｍ ／day

WK-75

3.75ｍ ／day

WK-1005.00ｍ ／day

333Water supply pumpN3-135(0.13KW)

Activated carbon
cylinder pump

C3-135(0.13KW)

Blower

LP-40(0.4KW)

WK-1507.50ｍ ／day

BlowerLP-80(0.85KW)

WK-20010.0ｍ ／day3333

■ For commercial use
The amount of water used varies depending on thepurpose ‒ ground plan, cross-section, type of business,
number of visitors, number of employees, businesshours, etc. Please consult with us during planning.
■ Recycling equipment
Calculations and/or reservoir size may vary dependingon the building purpose or recycling purpose. Please
consult with us during planning.
■ When applyingType of collection for non-discharge (closed loop)
human waste recycling equipment■ Comprehensive after-sales service
Double Clean will provide comprehensive service,from sales to installation to maintenance, in partnershipwith trusted local dealers.