INDUSTRIES / PHARMACEUTICALS
Pharmaceutical effluent treatment
built around segregation, not dilution.
Pharma effluent is strong, salty and different every batch. We test each stream in our NABL-accredited laboratory, split the strong streams from the weak ones, and design the ETP, solvent stripper, evaporator and reuse system around what your plant really discharges.
In short
How pharmaceutical effluent is treated.
A pharmaceutical effluent treatment plant treats wastewater from making bulk drugs (APIs), intermediates and formulations. It works by segregating the effluent at source: strong, salty streams such as mother liquors and solvent recovery residues go to a solvent stripper and multiple-effect evaporator (MEE), while weaker washing and utility streams go to a biological ETP followed by tertiary treatment and RO for reuse. Mixing everything together and hoping the biology copes is the most common reason pharma ETPs fail.
Under Indian rules, pharma units must meet the industry standards in the Environment (Protection) Rules, 1986, plus their SPCB consent, which for many bulk drug units means zero liquid discharge.
- 2lines
- High-strength (stripper and MEE) and low-strength (biological) treatment
- 17categories
- Highly polluting industries that need online monitoring; pharma is one of them
- 100mg/L
- BOD limit in the pharma industry standard (your consent may be stricter)
- ₹80–160/m³
- Running cost of our non-thermal evaporator, against an estimated ₹430–1,070 in an MEE
Where it comes from
What makes up pharma effluent?
A pharma plant does not produce one effluent. It produces six or seven very different streams, and their volume and strength change with each product campaign. Knowing them stream by stream is the start of every good design.
| Source | What it contains | Volume | Strength |
|---|---|---|---|
| Reaction mother liquors and aqueous layers | Unreacted raw materials, by-products, dissolved salts from neutralisation, dissolved solvents | Small | Very high COD and TDS; the stream that decides the plant |
| Solvent recovery residues and column bottoms | Water left after distilling methanol, acetone, toluene, IPA and similar solvents; tarry organics | Small | Very high COD, often toxic to bacteria |
| Equipment and floor washing | Product traces, detergents, solvents, cleaning acids and alkalis | Medium to large | Low to medium COD; first washes are much stronger than later rinses |
| Scrubber blowdown | Salts from scrubbing acid or alkaline vents (for example HCl, SO₂, ammonia) | Small | High TDS, low COD |
| Utility blowdowns | Boiler and cooling tower blowdown, RO and softener regeneration water | Medium | Low COD, moderate TDS |
| QC and R&D laboratory | Small volumes of solvents, reagents and samples | Very small | Variable; best collected separately |
| Domestic sewage | Toilets, canteen and change rooms | Medium | Biodegradable; useful as a nutrient source for the ETP biology |
Typical effluent characteristics
| Parameter | High-strength streams | Low-strength streams | Why it matters |
|---|---|---|---|
| COD | 20,000 to over 1,00,000 mg/L | 1,000 to 5,000 mg/L | Sets the organic load on the biology and the size of the stripper and evaporator |
| BOD : COD ratio | Often below 0.2 | 0.3 to 0.5 | A low ratio means much of the COD will not break down biologically |
| TDS | 20,000 to over 1,00,000 mg/L | 1,500 to 5,000 mg/L | Salt above roughly 1% upsets ordinary ETP bacteria and must be evaporated |
| pH | 1 to 13, batch dependent | 5 to 9 | Large swings kill biology unless equalised and neutralised |
| Solvents | Methanol, acetone, IPA, toluene, DCM and others | Traces | Add COD, odour and fire risk; some are toxic to bacteria |
| Ammoniacal nitrogen | Can be high where amines or ammonia are used | Low | Toxic to fish; needs stripping or nitrification |
| Toxicity (bio-assay) | Often toxic | Usually low | The pharma standard includes a fish bio-assay test |
Pharma effluent is hard for four reasons at once: high COD that bacteria cannot fully digest, high salt, dissolved solvents, and compounds (including antibiotic residues in some plants) that inhibit the very bacteria the ETP depends on. On top of this, the mix changes every time production switches products.
The key design idea
Why pharma effluent must be segregated.
Stream segregation means collecting the strong, salty effluent separately from the weak effluent at the point where it is produced, and treating the two in different lines. It is the single most important decision in a pharma ETP.
Here is why. Imagine a plant with 10 KLD of mother liquor at 60,000 mg/L COD and 50,000 mg/L TDS, and 90 KLD of washings and blowdowns at 2,000 mg/L COD and 2,500 mg/L TDS. Mixed together, the plant has 100 KLD at roughly 7,800 mg/L COD and 7,250 mg/L TDS. Three things now go wrong:
- The biology struggles. The salt and the hard-to-degrade organics from the small stream poison the large stream, so the outlet COD never comes down.
- The salt has nowhere to go. Bacteria do not remove TDS. All 100 KLD now carries salt, so to reach ZLD you must run RO and then evaporate a much larger reject flow.
- The evaporator gets bigger and costlier. Evaporating a dilute mixed stream costs far more than evaporating a small concentrated one.
Kept apart, the 10 KLD goes through a solvent stripper and an MEE, and the 90 KLD goes to a biological ETP that can work properly. The evaporator is sized for 10 KLD plus the RO reject, not for 100 KLD.
How we decide which stream goes where
We sample every stream over a full production campaign and test COD, BOD, TDS, pH, solvents and toxicity. As a starting point, streams with COD above about 15,000 mg/L or TDS above about 10,000 mg/L go to the high-strength line, and the rest go to the biological line. The final cut-off is set from a mass balance for your products, because a stream that is weak but toxic may also belong in the strong line.
Standards and rules
Which standards apply to pharma effluent?
The Environment (Protection) Rules, 1986 contain industry-specific standards for the pharmaceutical (manufacturing and formulation) industry, revised in 2009. They cover bulk drug units (synthetic, fermentation and natural extraction) and formulation units. The main values are below.
| Parameter | Pharma industry standard |
|---|---|
| pH | 6.0 to 8.5 |
| Oil and grease | 10 |
| BOD (3 days at 27 °C) | 100 |
| Total suspended solids | 100 |
| Bio-assay test | 90% survival of fish after 96 hours in 100% effluent |
| Mercury | 0.01 |
| Arsenic | 0.2 |
| Hexavalent chromium | 0.1 |
| Lead | 0.1 |
| Cyanide | 0.1 |
| Phenolic compounds | 1.0 |
| Sulphide | 2.0 |
| Phosphate (as P) | 5.0 |
Treatment scheme
A pharma ETP and ZLD, stage by stage.
This is the scheme we start from for a bulk drug unit. Formulation-only plants usually need only the low-strength line.
| Stage | What happens | Typical units |
|---|---|---|
| 1. Collect separately | Separate pipelines and holding tanks for high-strength and low-strength effluent, with a flow meter on each, so no strong batch reaches the biology by accident. | Segregated sumps, flow meters, first-wash tanks |
| 2. Equalise and neutralise | Each line holds at least one day's flow to even out batch swings, then pH is corrected. | Equalisation tanks with mixing, lime, caustic or acid dosing |
| 3. Strip solvents (strong line) | Steam strips volatile solvents such as methanol and acetone. COD falls sharply, fire and odour risk go, and the condensed solvent goes for recovery or authorised disposal. | Steam stripping column, condenser, solvent receiver |
| 4. Evaporate and dry (strong line) | Steam boils off water in several stages. The thick concentrate is dried to a salt cake for the TSDF. | Multiple-effect evaporator (MEE), agitated thin film dryer (ATFD) |
| 5. Biological treatment (weak line) | Bacteria acclimatised to your effluent digest the dissolved organics. Checked MEE condensate joins here. | Anaerobic reactor where COD allows, then extended aeration, MBBR or MBR; clarifier |
| 6. Polish | Residual solids, colour and stubborn COD are removed. | Pressure sand filter, activated carbon filter; Fenton or ozone where needed |
| 7. Recover water | Permeate goes to cooling towers, boilers and utilities. RO reject goes to the strong line, which closes the loop to ZLD. | Ultrafiltration (UF), reverse osmosis (RO) |
| 8. Handle sludge | Biological and chemical sludge is thickened and dewatered for authorised disposal. | Thickener, filter press or screw press |
Treatment options compared
| Option | Best for | Watch-outs |
|---|---|---|
| Steam stripper | High-strength streams with volatile solvents | Does not remove high-boiling solvents such as DMF or DMSO; needs steam |
| Anaerobic reactor (UASB or hybrid) | Low-strength streams with COD of a few thousand mg/L and little salt | Sensitive to toxicity and salt; slow to recover after an upset |
| Extended aeration or MBBR | Most low-strength pharma lines; MBBR handles shock loads better | Needs long retention and acclimatised biomass; foaming from surfactants |
| MBR | Plants that reuse water through RO; tight spaces | Membrane fouling if solvents or oils slip through |
| Advanced oxidation (Fenton, ozone) | Recalcitrant COD, colour, antibiotic residues before or after biology | Chemical cost; Fenton adds iron sludge |
| MEE + ATFD | High-TDS streams and RO reject in ZLD plants | The largest steam and running cost in the plant; scaling and foaming |
| Non-thermal RCD vaporiser | Taking part or all of the evaporation load off the MEE | Water is released to air, not recovered; output depends on weather and waste heat |
Our NABL-accredited laboratory tests COD, BOD, TDS, pH, ammoniacal nitrogen, solvents and bio-assay toxicity for each of your streams, and our engineers turn the results into a segregation plan and mass balance.
ZLD and resource recovery
ZLD for pharma, without the steam bill.
Zero liquid discharge (ZLD) means no effluent leaves the site as liquid: water is recovered for reuse and the salts leave as solid. In a pharma plant, the evaporator is the heart of ZLD and also its biggest cost. A steam MEE costs an estimated ₹430 to 1,070 to evaporate one cubic metre, and the MEE and ATFD together often take most of a ZLD plant's running cost.
Our non-thermal RCD vaporiser, developed with IIT Bombay, evaporates RO reject and stripped effluent on rotating disks using air instead of steam. It runs on a fan and a pump at about ₹80 to 160 per cubic metre. Pharma plants are a good fit because they already throw away low-grade heat: warm water from chiller condensers and steam condensate can feed the vaporiser and raise its output several times over.
Two ways to use it
- Beside an existing MEE: move 25 to 50% of the evaporation load to RCD units and keep the MEE for the rest. The MEE stays as back-up, so compliance is never at risk.
- In a new ZLD plant: where waste heat is available and the weather is hot and dry, RCD units can take the whole load before the dryer.
Other savings we look for
- Solvent recovery: a better stripper or distillation step returns solvent to the process and removes COD before it reaches the ETP.
- Water reuse: RO permeate replaces fresh water in cooling towers and boilers, often the largest water users on site.
- Smaller evaporators: segregation and better first-wash collection shrink the high-strength flow, which shrinks everything after it.
Cost
How much does a pharma ETP and ZLD plant cost?
For pharma, the high-strength flow drives the cost far more than the total flow. A 100 KLD formulation plant and a 100 KLD bulk drug plant with 15 KLD of mother liquor are different projects. Use these ranges to budget.
| Plant | Typical scope | Indicative cost* |
|---|---|---|
| Formulation unit, 20 to 50 KLD | Equalisation, biological ETP, tertiary filters | ₹15 to 45 lakh |
| Bulk drug, 100 KLD low-strength line | Equalisation, anaerobic or MBBR biology, tertiary, sludge handling | ₹60 lakh to 1.5 crore |
| High-strength line, 10 to 25 KLD | Stripper, MEE and ATFD | ₹1.5 to 4 crore |
| Full ZLD, about 100 KLD | Both lines plus UF, RO, MEE and ATFD | ₹4 to 10 crore |
*Indicative 2026 ranges for equipment, electricals and installation, excluding land, civil works and taxes. Solvent type, salt content, materials of construction (stainless steel or special alloys for corrosive streams) and automation change the figure a lot. We give a firm price only after testing your streams. Running costs are typically ₹30 to 100 per m³ for the biological line, ₹40 to 90 per m³ for UF and RO, and an estimated ₹430 to 1,070 per m³ evaporated in an MEE.
What drives capital cost
- Volume of high-strength effluent
- Solvent mix and the need for stripping
- Salt content and evaporator capacity
- Corrosion-resistant materials
- ZLD versus discharge
What drives running cost
- Steam for the stripper, MEE and ATFD
- Hazardous salt and sludge disposal at the TSDF
- Power for aeration and RO
- Chemicals for neutralisation and oxidation
- Membrane replacement
Where pharma plants lose money
- Mixing strong and weak streams
- Evaporators sized on mixed flow
- Solvents left in effluent instead of recovered
- No first-wash collection
- Waste heat ignored
We study your steam use and reject analysis, then run a sample trial and a site pilot of our non-thermal evaporator beside your MEE to measure the saving on your own stream.
Troubleshooting
Common pharma ETP problems, and how we fix them.
- 01The problem
Outlet COD stays high however long the effluent is aerated.
What we doMeasure the non-biodegradable COD, trace it to the stream it comes from and move that stream to the stripper and MEE line, or add advanced oxidation before the biology.
- 02The problem
The biology dies or foams after a product change.
What we doAdd equalisation and a toxicity check before new campaigns, feed new streams gradually, and keep a reserve of acclimatised biomass.
- 03The problem
The MEE scales, foams and shuts down for cleaning.
What we doStrip solvents properly before the MEE, correct the feed pH, dose tested antiscalants and antifoams, and move part of the load to RCD units that are cleaned online.
- 04The problem
MEE condensate has high COD or ammonia and upsets the ETP.
What we doImprove stripping ahead of the MEE, test the condensate regularly and route it to the right stage of the biological line.
- 05The problem
RO membranes foul within weeks.
What we doFix the upstream biology and filtration first, add UF, and supply antiscalants and cleaning chemicals matched to your feed analysis.
- 06The problem
OCEMS readings trigger alerts from the board.
What we doCheck analyser calibration against NABL lab results, then fix the process cause rather than the reading.
What we offer
What Rispri does for pharma plants.
Effluent testing
COD, BOD, TDS, solvents, metals and bio-assay in our NABL-accredited lab, for design and for compliance reports.
Testing services →ETP design and build
Segregated ETPs with stripper, biology and tertiary treatment, sized from a mass balance of your products.
Effluent treatment plants →Zero liquid discharge
UF, RO, MEE, ATFD and salt handling so nothing leaves the site as liquid.
ZLD plants →Non-thermal evaporator
RCD vaporisers that use air and waste heat to cut evaporation cost by about 80%.
Non-thermal evaporators →Treatment chemicals
Coagulants, antiscalants, antifoams, RO cleaners and boiler and cooling chemicals.
Water treatment chemicals →O&M and monitoring
Operators, monthly lab reports, OCEMS support and compliance help with your board.
EPC and O&M →Separately from our environmental work, Rispri also sources pharmaceutical intermediates and APIs for manufacturers.
Buying guide
What to ask before you buy a pharma ETP or ZLD.
Use these questions with any supplier, including us.
- Was every stream tested separately? Over a full campaign, not one mixed grab sample.
- Where is the segregation line drawn, and why? Ask for the mass balance behind it.
- What happens when the product mix changes? Equalisation volume, design margin and a plan for new products.
- Which solvents will the stripper remove? And what happens to high-boiling solvents it cannot remove.
- What is the steam use per m³ evaporated? And the cost of the salt cake going to the TSDF.
- Which materials are used for corrosive streams? Grades for the stripper, MEE and pipelines.
- Are outlet values and ZLD guaranteed? In writing, against your consent.
- Is OCEMS included? Analysers, data logger and CPCB connectivity.
Why Rispri
One team from stream test to running ZLD.
Our own NABL lab
We test every stream before design and certify the outlet after start-up, so the designer and the tester work together.
Engineering since 1999
1,498+ plants and turnkey projects for industry, hotels, hospitals and cities.
Institute-developed evaporation
Non-thermal evaporators developed with IIT Bombay, piloted beside your MEE before you commit.
Chemicals and O&M in house
Treatment chemicals, spares and trained operators from one team keep running costs predictable.
Questions
Pharmaceutical effluent treatment FAQs.
What is a pharmaceutical effluent treatment plant?
A pharmaceutical ETP treats wastewater from bulk drug, intermediate and formulation manufacture so that it meets the pharma industry standards and the unit's consent, or can be reused. In bulk drug units it usually has two lines: a stripper and evaporator for strong, salty streams and a biological ETP for weak streams.
Why is pharma effluent so difficult to treat?
It combines high COD, high TDS, dissolved solvents and compounds that are toxic to bacteria, and its composition changes with every product campaign. Much of the COD is not biodegradable, so biology alone cannot bring it within limits.
What is stream segregation in a pharma ETP?
Stream segregation means collecting strong, salty effluent such as mother liquors separately from weak effluent such as washings and blowdowns. The strong streams go to a solvent stripper and evaporator, and the weak streams go to biological treatment, so neither line is overloaded.
What are the CPCB standards for pharmaceutical effluent?
The pharma industry standards under the Environment (Protection) Rules, 1986 include pH 6.0 to 8.5, BOD 100 mg/L, TSS 100 mg/L, oil and grease 10 mg/L and a fish bio-assay with 90% survival, plus limits for metals, cyanide, phenolics, sulphide and phosphate. SPCB consents often add COD and TDS limits or require zero liquid discharge.
Is ZLD mandatory for pharma units?
There is no single national rule that makes ZLD mandatory for every pharma unit, but many bulk drug units hold consents that require it, especially in large clusters and water-stressed areas. Check your consent to operate; if it says no discharge, you need RO, an evaporator and a dryer.
What does an MEE do in a pharma ZLD plant?
A multiple-effect evaporator boils water out of high-TDS effluent and RO reject using steam in several stages, each reusing the vapour of the one before. The concentrate goes to an agitated thin film dryer, and the condensate is treated and reused.
Why is a solvent stripper needed before the MEE?
Volatile solvents in the feed carry over into the MEE condensate, causing high COD, odour and fire risk, and can cause foaming in the evaporator. A steam stripper removes them first, and the recovered solvent can go back to the process or for authorised disposal.
How much does a pharma ETP cost in India?
As an indication, a biological ETP for a 20 to 50 KLD formulation unit costs about ₹15 to 45 lakh, while a full ZLD for a 100 KLD bulk drug unit can cost ₹4 to 10 crore, excluding civil work and land. The volume of high-strength effluent is the biggest cost driver, so we price after testing.
How can we reduce the running cost of our MEE?
Segregate better so less flow reaches the MEE, strip solvents to cut scaling and foaming, and move part of the load to a non-thermal evaporator. Our RCD vaporiser costs about ₹80 to 160 per m³ against an estimated ₹430 to 1,070 in an MEE, and less where chiller or condensate heat can be used.
Does pharma effluent need online monitoring?
Yes. Pharmaceuticals are one of the 17 categories of highly polluting industries that must install online continuous effluent monitoring connected to the CPCB and SPCB servers. Units under ZLD may also be asked to monitor flows and the status of the evaporator.
Can antibiotic residues be removed from pharma effluent?
Partly by well-acclimatised biology and more reliably with advanced oxidation such as ozone or Fenton treatment, or by sending the antibiotic-bearing streams to the evaporator line. The right route depends on the molecule, so we start with a laboratory treatability study.
Where do pharma ETP salts and sludge go?
Evaporator salts, ETP sludge, distillation residues and spent carbon are hazardous waste under the Hazardous and Other Wastes Rules, 2016. They must be stored on site under authorisation and sent with manifests to an authorised TSDF, co-processing or incineration facility.
Do formulation units need the same plant as bulk drug units?
Usually not. Formulation effluent is mostly washing water with much lower COD and salt, so a well-designed biological ETP with tertiary treatment is often enough, unless the consent requires ZLD.
Related