ETP Cost for an Industrial Unit: Treatment Train, Sizing and Cost Drivers

The cost of an effluent treatment plant (ETP) for an industrial unit is set by four things: the daily flow in cubic metres, the pollution load in the water (organics, solids, oil, metals, salts), the standard the treated water must meet where it leaves, and whether it is reused. The treatment steps follow from load and standard. No price per kilolitre holds across industries, and this guide gives none.

What does an industrial treatment train look like?

Most plants are a sequence of stages, and the stages you need depend on what your process puts in the water. A food unit and a plating unit share the layout, not the contents.

What standard must the treated water meet?

The general standards are in Schedule VI of the Environment (Protection) Rules, 1986, notified in 1993. They give limits by where the water goes. A few of the common parameters are below, as maximum concentrations in mg/l unless stated.

These are the general limits. Sector-specific standards exist for many industries, and the State Pollution Control Board can set stricter conditions in your consent to operate. Some clusters require a common effluent treatment plant or zero liquid discharge instead of a private discharge. Your consent, not a generic table, defines the target. Read our CTE and CTO guide before the design is frozen, because the ETP flow-sheet is part of the application.

Schedule VI also lists wastewater generation standards for certain sectors, which act as a check on the water balance. Examples are 3 cubic metres per kilolitre of milk for a dairy and 0.4 cubic metres per tonne of cane crushed for a sugar mill. If your plant discharges far more than your sector's figure, find the leak or the wasteful step before sizing a larger ETP.

How is an ETP sized?

1. Build a water balance: intake, process use, cooling-tower blowdown, washdown and domestic use. Meter what you can.
2. Fix average and peak flow, including batch discharges and cleaning-in-place cycles.
3. Test the raw effluent. Take composite samples across a full production cycle, and test BOD, COD, suspended solids, oil, pH, total dissolved solids and any metals or specified chemicals.
4. Convert concentration to load. One mg/l in one cubic metre is one gram, so 100 m3/day at 1,500 mg/l BOD is 150 kg of BOD a day.
5. Size the units from flow, load and the retention time each stage needs. An equalisation tank holding 8 hours of a 100 m3/day flow is about 33 m3, before allowance for peaks.
6. Add growth, a standby for critical pumps and blowers, and sludge storage.

Our STP hydraulic load calculator estimates sewage flow from domestic water use. Use it for the canteen and toilet stream only. It does not apply to process effluent, which needs its own sampling and design.

What moves the cost?

Each driver below changes the size of a unit or the type of unit, which is what changes the price:

• Flow and peaks: tank volumes, pump sizes and footprint.
• Strength of the effluent: stronger organic load needs a larger biological stage or an anaerobic stage ahead of it.
• Dissolved salts and difficult chemicals: these push a plant toward membranes and evaporation, which raise both capital and running cost.
• Discharge route: surface water, sewer, irrigation, reuse and zero liquid discharge each need a different final stage.
• Materials: mild steel, FRP, HDPE or lined concrete, chosen against acidity and chloride.
• Automation and monitoring: your consent may require online measurement for some industries.
• Running costs: power, chemicals, labour and sludge disposal. A plant that is cheaper to build can cost more to run.
• Commissioning: a biological stage must be seeded and stabilised, which takes weeks, so build it into the programme.

Treat the purchase as a budget range until the sampling is done. A quotation that does not state the design flow, the design influent quality and the guaranteed outlet quality cannot be compared with another.

What should an ETP quotation state?

Use this list when you review bids. A line that is missing is usually a cost that arrives later.

How Secured Engineers helps

Plumbing and public health is one of our in-house design disciplines, covering STP, WTP and ETP integration alongside water supply and drainage. We prepare consent papers for the pollution board with the rest of the approvals, and MEPF and solar can sit under one contract. We work from offices in Noida (Delhi NCR) and Ludhiana, with 535+ projects across 18+ states and 89.77% repeat clients. We do not quote a figure for an ETP before the effluent is characterised.

If you have an ETP quotation or budget, send it with the water balance and lab results, and we will review it for missing stages and unstated assumptions. See our plumbing and public health service, message us on WhatsApp, call +91 70099 85817, or ask for a free proposal.