Dosing system supplier in Bangladesh

Roptan is your dosing system supplier in Bangladesh for ETPs and membrane plants. Send your chemical list, flow and lab results: we source metering pumps, tanks and pH control from verified sellers, check the materials against each chemical and deliver.

Verified sellers
Checked before it ships
Delivered by Roptan

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

Buying dosing systems in Bangladesh

A dosing system feeds treatment chemicals into an ETP at a controlled rate: a tank, often a mixer, a metering pump and, for pH, a probe and controller. A dyeing ETP may need separate lines for acid, alkali, coagulant, polymer and nutrients, and a membrane plant adds more. Factories in Bangladesh buy one with a new plant, to replace hand dosing, or to bring chemical use under control.

A dosing system supplier in Bangladesh should match each pump, diaphragm and pipe to the chemical it carries. Roptan sends your chemical list and lab results to verified sellers, compares the dosing points, materials, controls and spares in each quote, and arranges installation and commissioning through the seller you choose.

Kinds of dosing system

pH correction dosing

Acid and alkali lines run by an automatic pH controller that tests and adjusts continuously. Choose it ahead of coagulation and any biological stage; provide both chemicals, since some dyeing processes give acid effluent.

Coagulant dosing

A metering pump feeds alum, an iron salt or PAC into the rapid mixing stage. Choose the pump size and turn-down from your jar tests and flow.

Polymer dosing

Polymers come cationic, anionic or non-ionic and are dosed at a gentle mixing stage after the coagulant. The package needs make-up and ageing tanks for the polymer solution.

Nutrient dosing

Urea and ammonium phosphate fed to the biological stage, because textile effluent is usually short of nitrogen and phosphorus. Choose it whenever the ETP has a biological stage.

Membrane dosing and cleaning

Antiscalant and bisulphite ahead of reverse osmosis, plus acid, caustic and hypochlorite for membrane cleaning. Choose it as part of any recycling or ZLD plant.

How to specify a dosing system

Pump type: Diaphragm metering pumps are usual for chemicals: the diaphragm seals the liquid in, and its rate is set by stroke length or speed. Name the diaphragm elastomer for each chemical.
Variable speed: Ask for variable-speed metering pumps so rates can be changed accurately. Hand-set valves and taps cannot hold a dose.
Wetted materials: Hydrochloric acid attacks concrete and steel and can corrode stainless steel, so pH dosing pumps and pipes should be plastic or suitably coated.
pH probes: Industrial electrodes the maker rates for ETP use, with spares in stock. With a biological stage after it, keep the set point inside pH 6 to 8.
Dose and pump size: Size pumps and tanks from your equalisation tank analysis and jar tests, not effluent colour, so the turn-down range covers light and dark shades.
Flow pacing: Ask whether dosing follows the flow. An equalisation tank keeps the feed steady enough for fixed-rate pumps; without one, dosing must track the surges.
Panel protection: Ask for the IP rating of the panel and pump drives under IEC 60529 for a damp chemical room or an open yard.

Standards and safety papers for dosing systems

IEC 60529: Defines the IP code: the first digit for dust, where 5 is dust protected and 6 dust tight, the second for water, where 4 to 6 cover splashing up to powerful jets.
EN ISO 10523: The laboratory method for pH. Use it to check the online pH reading at commissioning, not as a requirement on the controller itself.
Safety data sheets to GHS: One for each chemical, with the PPE, eyewash and bunding the design assumes for handling caustic soda, hydrochloric acid and the rest.
EN ISO 12100: The general method for machinery risk assessment. For a skid-mounted unit, ask how the design dealt with chemical, moving-part and electrical hazards.

What moves the price of a dosing system

The number of chemicals and dosing points, each with its own pump and tank.
Pump size and turn-down range.
Wetted-part and diaphragm materials matched to each chemical.
Duty and standby pumps against a single pump per line.
Tank volume, mixers and polymer make-up tanks.
An automatic pH controller with probes, flow meters and the panel, against manual control.

Lead times and delivery

Dosing systems have no fixed lead time. The number of dosing lines, imported pumps and controllers, special materials for strong acids and the panel build move the date most. Testing each line on site at commissioning flow adds a little time but catches wrong doses early. Roptan confirms the dates in the quote.

We deliver pumps, tanks, mixers, pH controllers and the panel to your ETP anywhere in Bangladesh and arrange installation and commissioning through the seller. Handover should include the dosing chart, a delivered-volume check for each pump, the chemical list with safety data sheets, spare diaphragms and electrodes, and a VAT invoice (Mushak 6.3).

What we check for this order

Delivered volume against settingWe ask the seller to run each pump at the commissioning flow and compare the volume delivered with the pump setting.
pH loop through a production changeWe check the pH controller holds its set point when production changes, not only during a quiet hour.
Materials against the chemical listWe match each pump, diaphragm, tank and pipe to the chemical it carries, acids first.
Spares in the quoteWe confirm spare diaphragms, electrodes and tubing are included, and that the supplier for vital parts can be reached.

Questions buyers ask

Why not dose with valves or by gravity?

Because the dose cannot be held. Hand-adjusted valves and taps are inaccurate, so no standard operating practice can be built on them, and chemical cost control is unlikely without standard dosing. Variable-speed metering pumps let the operator set and repeat a dose from the dosing chart.

Do we need both acid and alkali dosing?

Usually, yes. Dyeing effluent in Bangladesh is generally highly alkaline and needs acid, but some dyeing processes give acid effluent, so provision for both is recommended. An automatic controller then adds whichever the reading calls for.

How often should pH be checked without a controller?

At least every 2 hours, with a pH meter and an industrial electrode. pH paper is inaccurate with coloured effluent. An automatic controller that tests and adjusts continuously is the better answer, and an older Bangladesh guide says it will prove cost effective.

Which spares should we keep?

Spare diaphragms for each pump, pH electrodes and tubing, at the least. Spares for vital units should be on site or with a supplier you can reach quickly, so a failed part does not stop a dosing line for long.

How soon will I hear back about ETP plant?

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.