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Water and wastewater

Johkasou supplier in Bangladesh

Roptan acts as your johkasou supplier in Bangladesh. Tell us how many people use the building and where the treated water goes, and we source a unit sized to that load, its blower and a service plan from verified sellers, and deliver to site.

  • Verified sellers
  • Checked before it ships
  • Delivered by Roptan

Get johkasou sourced

Prefer to deal with suppliers yourself? Post it on the requirement board

Johkasou products

Pick a product and we source it for you, or send one requirement that covers several.

5 person johkasouSingle family houseGet it sourced10 person johkasouLarge house or duplexGet it sourced50 person johkasouSmall building or schoolGet it sourcedCommercial johkasouOffices, restaurants, resortsGet it sourcedJohkasou blowersRuns day and nightGet it sourcedJohkasou servicingInspection, desludging, disinfectantGet it sourced

Buying johkasou in Bangladesh

A johkasou is a compact buried treatment tank, standardised in Japan under the Johkasou Act, that treats toilet, kitchen and bath water from one house or building. Where there is no sewer, which is most of Bangladesh, it suits houses, small apartment blocks, schools, clinics, resorts and site offices in Dhaka and beyond. A johkasou supplier in Bangladesh should size it from the people served and the building's use, and show the calculation.

You send the requirement once. We source the unit and its blower from verified sellers, check the model's documents, sizing and warranty, and compare installed prices that include excavation, base slab and connections. We deliver to site; the seller or its trained installer sets the tank and starts it, and the service plan is agreed before handover.

Johkasou we source

5 person johkasou

The smallest common size, for one household. It needs a small excavation, a concrete base and a power point for the blower. Place it where the lids stay reachable for inspection and desludging, usually outside the building line.

10 person johkasou

For a larger household, a duplex or two small flats. Count residents, domestic staff and regular visitors, since sizing is by people served, and choose the next size up where the count falls between sizes.

50 person johkasou

For a small apartment block, office, clinic, school block or site office. Units this size often need a crane to set and must be anchored to a base slab where groundwater rises in the monsoon. Compare it with a small packaged STP on installed price and service cost.

Commercial johkasou

Larger units, or several in series, for hotels, resorts, restaurants, offices and factory canteens and washrooms. They are sized from building use and daily flow in m³ rather than headcount alone, and kitchens need a grease trap ahead of the unit, because fats clog the media.

Johkasou blowers

A small diaphragm air blower feeds the aerobic chambers around the clock. Its diaphragms and valves wear and are replaced on a schedule, so keep a spare blower and a diaphragm kit. Mount it above flood level, in shade, on a supply that stays live through load shedding.

Johkasou servicing

Regular checks of the blower, air flow and outlet water, desludging by vacuum tanker when sludge builds up, and refills of chlorine disinfectant tablets. Japan's Johkasou Act requires this upkeep there; in Bangladesh it depends on your contract, so price a service plan with the unit.

How to specify a johkasou

Persons served
Count everyone who uses the building daily, with a margin for guests and growth. Japan sizes johkasou by building use under JIS A 3302; ask how the seller applied that to your building.
Building use and water
A house, school, clinic or restaurant loads a unit differently for the same headcount. Beyond a house, give the daily water use in m³, and say whether kitchen and bath water join the toilet water.
Outlet level
Say where the outlet goes, drain, canal or soak pit, and give its level. The outlet must sit above the drain's monsoon water level, or it backs up and a pump is needed.
Groundwater and flotation
Give the highest groundwater level. A buried FRP tank can float when groundwater is high, so wet sites need a concrete base with anchor straps or ballast, priced separately.
Traffic loads and access
Under a driveway or car park, specify a reinforced concrete slab over the unit, carried on its own supports, not on the tank. Give a route for a truck or small crane.
Blower power
Small units run on single phase, 50 Hz. Put the blower on the IPS or generator circuit so aeration continues through load shedding, in a covered, ventilated spot.
Service plan
Inspection, blower care, tablets and desludging priced for one, two or three years, so the full cost is visible before you order.

Paperwork to ask a johkasou supplier in Bangladesh for

Johkasou Act (Japan)
Johkasou are standardised under this Japanese law, which also requires regular inspection and desludging there. Ask for the maker's performance documents and whether the unit is Japanese-made or a similar design made elsewhere.
JIS A 3302
The Japanese standard for counting persons served by building use. Ask for the sizing calculation based on it, so the unit is not undersized for your building.
ECR 2023
The Environment Conservation Rules 2023 set limits for treated water discharged to drains and water bodies. Ask the seller to state the expected outlet BOD and TSS in writing.
Installation and outlet test record
Base and anchoring photos before backfill, water level check, blower air flow, leak check, and an outlet test by an ISO/IEC 17025 accredited lab once the biology has settled.

What moves the price of a johkasou

  • Capacity in persons, which sets the tank size and blower rating; the price per person usually falls as size rises.
  • Origin and design: Japanese-made units and similar designs made elsewhere differ in price and parts supply.
  • Model type: standard units, or advanced units that also remove nitrogen and phosphorus.
  • Site work: excavation, dewatering, the concrete base, anchoring, backfill, any traffic slab, and a crane for larger units.
  • Servicing: blower spares, disinfectant tablets and desludging, bought as needed or as a yearly contract.

Lead times and delivery

Units held in stock in Bangladesh can typically be delivered within 1 to 3 weeks; units imported to order usually take 8 to 12 weeks, including sea freight and clearance at Chattogram. Installation takes days for a small unit, longer where the ground is wet or a crane is needed, and the biology needs a few weeks before the outlet is tested. Roptan confirms each date in the quote.

We deliver to site across Bangladesh. The seller or its trained installer sets the tank on its base, anchors it, backfills while filling the tank with water to balance the pressure, connects the inlet, outlet, vents and blower, and starts the unit. Handover includes the installation record with photos, the maintenance schedule, tank and blower warranties and a VAT invoice (Mushak 6.3).

What we check for this order

  • Trade licence and installation recordWe confirm the seller's licence and ask for units running in Bangladesh, with the client named, before we shortlist.
  • Design basis and discharge standardPersons served, design flow and expected outlet values go into the quote, matched to the model's documents, so there is a reference if the outlet is poor.
  • Warranty and after sales in writingTank, blower and installation cover, service visits, diaphragm kits and desludging, included or priced, confirmed before you commit.
  • A visit to a working installationBefore the order is placed, we arrange a look at a running unit of similar size and its service log, so you see what upkeep involves.

Questions buyers ask

Is a johkasou better than a septic tank?

For treatment, yes. A septic tank settles solids but leaves much of the dissolved organic load in the water. A johkasou adds aerated treatment, settling and disinfection, so the outlet is far cleaner. It needs power for the blower and regular servicing, which a septic tank does not.

Is a johkasou cheaper than a small STP?

For a house or small building, usually yes, and it needs less space and no plant room. For larger buildings, a packaged STP can compete, so ask for both when you are in between. Compare installed price, power use and service cost over several years, not the unit price alone.

Can a johkasou go under a car park or where the ground floods?

Yes, with care. Under traffic, a reinforced concrete slab must carry the vehicle load on its own supports, with the lids reachable for desludging. On wet ground, the tank is anchored to a concrete base so it cannot float, the covers sit above flood water and the blower is mounted high and dry.

What happens if the blower stops during load shedding?

The aerobic chambers lose air and treatment falls within hours, with odour following. A small johkasou blower draws little power, so connect it to the IPS or generator. After long outages, check that the blower restarted and air is flowing.

How often does a johkasou need desludging?

The seller's manual sets the interval for your unit and use; once a year is common, and heavy use or a busy kitchen shortens it. Inspections show when sludge has built up. Plan tanker access to the lids from the start, and confirm who provides desludging near your site.

How soon will I hear back about johkasou?

Within 48 hours of a complete requirement, with a price and a delivery date. A requirement is complete when it has the capacity, where it is needed and by when.

Who do I deal with?

With Roptan, when Roptan manages the order: we buy from the verified seller and deliver to you. With the supplier directly, when you post on the requirement board and choose a quote yourself.

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