INDUSTRIES / FOOD AND BEVERAGE
Wastewater treatment for food and beverage plants
that turns strong effluent into fuel and reusable water.
Food and beverage effluent is easy for bacteria to eat but hard on a plant that was not designed for it: fats clog pipes, sugars swing the pH and seasonal loads overwhelm the biology. We test your effluent in our NABL-accredited laboratory and design an ETP around what your lines actually discharge.
In short
How food and beverage effluent is treated.
Food and beverage wastewater is high-strength but biodegradable: it carries sugars, starch, fats, oil and grease (FOG) and proteins, often at a COD of 2,000 to 10,000 mg/L, with sharp pH swings from caustic cleaning. A food-industry ETP usually works in four steps: screening and fat removal (fat trap or DAF), equalisation and pH correction, biological treatment (an anaerobic UASB or IC reactor that makes biogas when COD is high, then aerobic polishing by MBBR, activated sludge or SBR) and tertiary filtration, with UF and RO when water is reused. Under India's general standards, treated effluent discharged to surface water must meet BOD 30 mg/L, COD 250 mg/L and oil and grease 10 mg/L, unless your consent says otherwise.
- 0.5to 0.7
- Typical BOD/COD ratio of food effluent, which means it is readily biodegradable
- 0.35m³ CH₄
- Theoretical methane from each kg of COD removed in an anaerobic reactor
- 10mg/L
- Oil and grease limit for discharge into inland surface water
- NABL
- Accredited laboratory that tests your effluent and your process water
Where it comes from
Where does wastewater come from in a food or beverage plant?
Very little food effluent comes from the product itself. Most of it is cleaning: tanks, lines, crates, bottles and floors washed between batches. What changes from one sub-sector to another is what that wash water picks up.
| Sub-sector | Main wastewater sources | What the effluent carries |
|---|---|---|
| Beverages and bottling (soft drinks, juices, packaged water) | CIP (clean-in-place) of syrup rooms and fillers, returnable bottle washers using hot caustic soda, product changeovers, rejected batches, RO reject and filter backwash | Sugar, flavours, high pH (often above 10 from bottle washer caustic), label pulp and glue, high TDS from the water plant |
| Breweries | Brewhouse and fermenter cleaning, spent grain and yeast handling, filter rinses, bottle and keg washing | Sugars, alcohol, yeast and protein solids, caustic and acid CIP residues, warm water |
| Distilleries | Spent wash from distillation (the main stream), plus cooling and cleaning water | Extremely strong, dark and acidic effluent; a special case covered below |
| Snacks, namkeen and chips | Potato and grain washing, peeling and slicing, fryer cleaning, floor washing | Starch, soil and peel solids, frying oil and fats |
| Edible oil and refining | Degumming and neutralisation, soapstock splitting with acid, deodoriser condensate, tank and floor washing | Free and emulsified oil, soaps, low pH from acid splitting, phosphates and sulphates |
| Bakery, biscuit and confectionery | Mixer, tray and mould washing, cooking kettle cleaning, rejected product | Sugar, starch, fats and butter, cocoa and colours; very low in nitrogen |
| Fruit and vegetable processing | Washing, blanching, peeling (sometimes with lye), pulping and canning | Soil, peel, pulp, sugars and organic acids; strongly seasonal. See our pea processing guide |
| Dairy | Whey, milk spills, CIP | Lactose, milk fat and protein. See our dairy guide |
Typical effluent characteristics
| Parameter | Typical range | Why it matters |
|---|---|---|
| pH | 4 to 12, changing within a shift | Caustic washes push it up, sugars ferment and pull it down. Bacteria want 6.5 to 8.5, so equalisation and dosing are needed. |
| COD | 1,500 to 10,000 mg/L (higher for confectionery and rejected product) | Above roughly 3,000 to 4,000 mg/L an anaerobic stage usually pays for itself through lower power and biogas. |
| BOD | 800 to 6,000 mg/L | Sets the oxygen, and therefore blower power, an aerobic plant needs. |
| BOD/COD ratio | 0.5 to 0.7 | A high ratio means most of the load is easily eaten by bacteria, so biological treatment works well. |
| Oil and grease (FOG) | 100 to 1,000 mg/L or more in snack and oil units | Coats biomass, blocks pipes and diffusers, and causes floating scum. Must come out first. |
| Total suspended solids | 300 to 2,000 mg/L | Peel, starch, grain and label pulp settle in tanks and fill them if not screened. |
| Nitrogen and phosphorus | Often too low for the BOD load | Sugary effluent lacks nutrients; bacteria then grow badly and sludge bulks unless urea and phosphate are dosed. |
| TDS | 1,000 to 4,000 mg/L | Comes from caustic, acids, salt and RO reject. Matters when the board limits TDS or you want to reuse water. |
| Temperature | 30 to 45 °C at source | Hot washes speed up fermentation and odour in sumps; helpful for anaerobic reactors. |
What BOD, COD and FOG mean
BOD (biochemical oxygen demand) is the oxygen bacteria use to eat the organic matter in a sample over a few days. COD (chemical oxygen demand) is the oxygen needed to oxidise it chemically, so it counts nearly everything organic. When BOD is more than half of COD, as in most food effluent, the waste is "readily biodegradable". FOG is fats, oil and grease, measured together as oil and grease.
Distillery spent wash: a special case
Molasses-based distilleries produce spent wash with a COD that often runs into tens of thousands of mg/L and can exceed 1,00,000 mg/L, along with a dark colour that biology does not remove. CPCB requires zero liquid discharge for spent wash, so the usual route is biomethanation to recover biogas, then concentration by evaporation and incineration in a boiler or composting with press mud. Grain-based distilleries handle their thin slop differently. Read about ZLD plants and biogas from waste.
Rules
Which discharge standards apply to a food plant?
Most food and beverage units are held to the general standards in Schedule VI of the Environment (Protection) Rules, 1986, through the consent to operate issued by the State Pollution Control Board under the Water Act, 1974. These are the values that matter most for food effluent.
| Parameter | Inland surface water | Public sewer | Land for irrigation |
|---|---|---|---|
| pH | 5.5 to 9.0 | 5.5 to 9.0 | 5.5 to 9.0 |
| BOD (3 days at 27 °C) | 30 | 350 | 100 |
| COD | 250 | As per consent | As per consent |
| Total suspended solids | 100 | 600 | 200 |
| Oil and grease | 10 | 20 | 10 |
| Ammoniacal nitrogen (as N) | 50 | 50 | As per consent |
Treatment
The treatment scheme for food and beverage effluent.
The rule for food effluent is simple: take the fat out first, even out the flow, let anaerobic bacteria take the bulk of a strong load, and use aerobic bacteria to finish the job.
Screening
A fine screen of 1 to 3 mm, or a rotary drum screen, catches peel, grain, label pulp and broken product before they reach the tanks. Collected solids can go to cattle feed or a biogas digester.
Fat and oil removal
A gravity fat trap removes free fat that floats. Emulsified fat needs a dissolved air flotation (DAF) unit, where fine air bubbles and a coagulant lift fat and fine solids to the surface to be skimmed.
Equalisation and pH correction
A mixed tank holding several hours of flow absorbs CIP dumps and caustic bottle washer drains. Acid or alkali is dosed to bring pH to 6.5 to 8.5, and urea and phosphate are added if nutrients are short.
Anaerobic treatment (for strong effluent)
A UASB (upflow anaerobic sludge blanket) or IC (internal circulation) reactor lets anaerobic bacteria turn most of the COD into biogas, with little sludge and no aeration power. Often 70 to 85% of the COD is removed here.
Aerobic polishing
MBBR, extended aeration activated sludge or SBR removes the remaining BOD and ammonia, followed by a clarifier. For weaker effluent this is the only biological stage.
Tertiary and reuse
A pressure sand filter and activated carbon filter polish the water. Ultrafiltration (UF) and reverse osmosis (RO) make it fit for cooling towers and boilers.
Sludge handling
Excess sludge is thickened and dewatered in a screw press or filter press. Food ETP sludge is organic and often suitable for composting or co-digestion, subject to testing and board approval.
Which biological option fits your plant?
| Option | Best for | Strength | Watch-outs |
|---|---|---|---|
| Aerobic only (MBBR, ASP or SBR) | COD below about 3,000 mg/L, small flows, bakeries, bottling plants with returnable bottles | Simple, quick to start, stable outlet | Blower power rises steeply with load; more sludge to dispose of |
| UASB + aerobic polish | Breweries, confectionery, starch, juice and snack units with steady high COD | Biogas fuel, much less power and sludge | Needs fats removed first; granular sludge takes weeks to establish; sensitive to pH shocks |
| IC or EGSB reactor + aerobic | Large breweries and beverage plants with little space | Tall, compact, handles higher loading than UASB | Higher capital cost; needs good control and seeding |
| Anaerobic lagoon or covered digester | High-solids or very fatty streams where land is available | Tolerates solids and fat better | Large area; odour if not fully covered |
| MBR | Plants that want direct reuse with a small footprint | Excellent outlet, RO-ready | Fat fouls membranes; higher power and membrane cost |
Volumetric loading of a UASB on food effluent is typically in the region of 5 to 15 kg COD per m³ per day; IC reactors run higher. We size the reactor from your measured COD and flow, not from a rule of thumb.
Our NABL-accredited lab tests pH, BOD, COD, oil and grease, TSS, TDS, nitrogen and phosphorus on composite samples over a full production cycle, so the fat trap, reactor and blowers are sized on real numbers.
Reuse and recovery
Biogas, sludge and water: what your effluent is worth.
Food effluent is one of the few wastewaters that can pay back part of its own treatment cost.
Biogas from COD
Each kg of COD removed anaerobically can, in theory, yield about 0.35 m³ of methane; in practice biogas is usually 60 to 70% methane. A plant removing 2,000 kg of COD a day can make several hundred cubic metres of biogas a day for boilers or thermic fluid heaters, replacing LPG, furnace oil or coal. See waste-to-energy and Bio-CNG.
Solid wastes as feedstock
Screenings, peel, spent grain, rejected product and DAF float are good feed for a biogas digester or for composting. Separating them dry, rather than washing them into the drain, cuts the ETP load at the same time.
Water back into utilities
After UF and RO, treated effluent can feed cooling towers, boilers, crate and floor washing and gardening. Where tanker or borewell water is costly, reuse of 50 to 70% of the ETP outlet is a realistic target, with the RO reject handled separately.
When ZLD comes into the picture
Distilleries must achieve zero liquid discharge, and some boards now ask food units in water-stressed areas to do the same. The RO reject then needs evaporating. Our non-thermal evaporators evaporate reject using air instead of steam, at about 80% lower cost per cubic metre than a conventional multiple-effect evaporator (MEE), and our RO reject research works on recovering more water first.
Process water
The water going in matters as much as the water going out.
Food safety rules care about the water you use, not only the water you discharge. FSSAI's licensing conditions require that water used as an ingredient, or that touches food or food-contact surfaces, is potable, and the reference for potable water in India is IS 10500:2012, which sets limits such as pH 6.5 to 8.5 and TDS 500 mg/L (acceptable). Packaged drinking water and mineral water units have their own BIS standards, IS 14543 and IS 13428.
In practice this means three things for a plant manager. Test your raw and treated water regularly in an accredited laboratory and keep the reports for audits. Soften or demineralise water for boilers, cooling towers and bottle washers, because hardness scale wastes fuel and caustic. And keep treated effluent away from anything that touches food: recycled ETP water belongs in cooling towers, boilers (after RO), utility washing and gardening, not in product.
Cost
How much does a food industry ETP cost?
For food effluent, COD decides the cost far more than flow. A 100 KLD bottling plant ETP and a 100 KLD confectionery ETP can differ several times over in price.
| Capacity | Typical plant | Usual scheme | Indicative plant cost* |
|---|---|---|---|
| 20 to 50 KLD | Bakery, small snack or juice unit | Screen, fat trap, equalisation, MBBR, filters | ₹12 to 40 lakh |
| 100 KLD | Bottling plant, mid-size snack unit | Fat trap or DAF, equalisation, MBBR or SBR, filters | ₹30 to 75 lakh |
| 250 KLD | Brewery, confectionery, edible oil unit | DAF, equalisation, UASB, MBBR, filters | ₹80 lakh to 1.8 crore |
| 500 KLD and above | Large brewery or beverage complex | DAF, UASB or IC with biogas use, aerobic polish, UF/RO | ₹1.5 crore upwards |
*Indicative 2026 ranges for equipment, electricals and installation, excluding land, civil works, taxes, biogas utilisation equipment and any RO or ZLD stage. We give a firm price after testing your effluent and visiting the site.
What drives capital cost
- COD and FOG load, not only KLD
- Whether an anaerobic reactor is justified
- DAF instead of a simple fat trap
- Reuse targets (UF, RO) or ZLD
- Space, soil and civil vs steel tanks
What drives running cost
- Aeration power for the aerobic stage
- Caustic or acid for pH correction
- Coagulant and polymer for DAF
- Urea and phosphate for nutrients
- Sludge dewatering and disposal
What can offset it
- Biogas replacing boiler fuel
- Lower aeration power after UASB
- Reused water replacing tanker water
- Less sludge from anaerobic treatment
- Source reduction in the factory
Troubleshooting
Common problems in food plant ETPs, and how we fix them.
- 01The problem
Fat blocks drains, pumps and diffusers, and a grey scum covers the aeration tank.
What we doResize or add a fat trap, add DAF for emulsified fat, keep hot washes from melting fat past the trap, and set a skimming and cleaning schedule.
- 02The problem
Thick foam builds up on the aeration tank.
What we doIdentify whether it is detergent foam from CIP or biological foam from filamentous bacteria fed by fats, then fix the cause: source control, sludge age or fat removal, with antifoam only as a stopgap.
- 03The problem
Sludge will not settle and the clarifier overflows solids (bulking).
What we doSugary effluent short of nitrogen and phosphorus is a classic cause. We check nutrients, dissolved oxygen and the microscope picture, then correct dosing and load.
- 04The problem
Seasonal or festival peaks double the load and the outlet fails.
What we doDesign equalisation for the peak season, add MBBR media to raise capacity in the same tank, and keep biomass alive in the off-season.
- 05The problem
Sour, rotten-egg odour from sumps and equalisation tanks.
What we doSugars ferment within hours in warm, still water. We add mixing or aeration in equalisation, cut holding times and cover and scrub odour sources where needed.
- 06The problem
The UASB turns sour and biogas falls.
What we doMonitor volatile fatty acids and alkalinity, protect the reactor from caustic dumps and fat, and recover the granular sludge with controlled loading.
What we offer
What Rispri does for food and beverage plants.
Effluent and water testing
NABL-accredited tests of effluent, process water to IS 10500, sludge and microbiology.
Testing →Biogas and Bio-CNG
Recover energy from strong effluent and organic solid waste.
Waste to energy →Softeners and RO
Soft water for boilers, cooling towers and bottle washers.
Water softeners →ETP, boiler and cooling chemicals
Coagulants, polymers, nutrients, antifoams and descalers tested on your water.
Chemicals →Operation and maintenance
Trained operators, monthly lab reports and board compliance support.
EPC and O&M →Buying guide
What to ask before buying a food industry ETP.
Use this list with any supplier, including us.
- Was the design based on composite samples from my peak season? A single grab sample in a slow week will undersize the plant.
- How is fat removed, and what FOG does the biology see? Ask for the design oil and grease value at the reactor inlet.
- Is an anaerobic stage justified, and what will the biogas be used for? Ask for the expected biogas and fuel saving per day.
- How are CIP and caustic dumps handled? Equalisation volume and pH control should be shown in the calculation.
- What is the running cost per cubic metre? Power, chemicals, nutrients and sludge, listed separately.
- Which outlet values are guaranteed? In writing, against the limits in your consent.
- Where will treated water be reused, and where will the reject go?
- Who tests the outlet after start-up? A NABL-accredited report carries weight with the board and auditors.
Why Rispri
Engineering and testing under one roof.
Our own NABL lab
We test your effluent before design and your outlet and process water after start-up.
Engineering since 1999
1,498+ plants and turnkey projects for industries, hotels, hospitals and cities.
Biogas and reuse in the design
We look at what your effluent can give back, not only how to get rid of it.
Chemicals, spares and O&M
Treatment chemicals and spares from our own catalogue, and operators who keep the plant compliant.
Questions
Food and beverage effluent FAQs.
What is an ETP for the food industry?
It is an effluent treatment plant designed for wastewater rich in sugars, starch, fats and proteins. It usually combines screening, fat removal, equalisation, biological treatment (often anaerobic then aerobic) and filtration, so that the treated water meets the consent limits or can be reused in utilities.
Is an ETP mandatory for a food processing unit?
If your unit discharges process wastewater, the State Pollution Control Board will require treatment to the limits in your consent to establish and consent to operate under the Water Act, 1974. Very small units may be allowed to send pre-treated effluent to a sewer or CETP, but only with the board's approval.
Why is food industry wastewater so strong?
Because the product itself is organic. Syrup, milk, starch, oil and rejected product washed into the drain add a large organic load, so food effluent often has a COD of several thousand mg/L, many times stronger than domestic sewage.
What are the discharge limits for food industry effluent?
Most food units follow the general standards: for inland surface water, pH 5.5 to 9.0, BOD 30 mg/L, COD 250 mg/L, TSS 100 mg/L and oil and grease 10 mg/L. Dairies, sugar mills, distilleries and breweries and edible oil units have sector-specific standards, and your consent can be stricter.
How is soft drink and bottling plant wastewater treated?
Bottling effluent is mainly sugar plus caustic from bottle washers and CIP. It is equalised and neutralised, then treated biologically, usually by MBBR or activated sludge, and an anaerobic stage is added when COD is high. Treated water is often reused in cooling towers or crate washing after filtration and RO.
How is brewery wastewater treated?
Brewery effluent is strong and biodegradable, so most medium and large breweries use a UASB or IC anaerobic reactor that turns the bulk of the COD into biogas, followed by aerobic polishing. Spent grain and yeast should be kept out of the drain and sold or digested separately.
Can food processing effluent produce biogas?
Yes. In an anaerobic reactor, each kg of COD removed can in theory produce about 0.35 m³ of methane. Biogas is usually worth recovering when effluent COD is above about 3,000 mg/L and the plant has a steady flow and a boiler or heater to use the gas.
What is a DAF and do I need one?
A dissolved air flotation (DAF) unit releases fine air bubbles that lift fat, oil and fine solids to the surface, where they are skimmed off. You need one when your effluent contains emulsified fat that a simple gravity fat trap cannot catch, which is common in snack, edible oil, bakery and dairy units.
Can treated ETP water be reused in a food factory?
Yes, but not in the product or on food-contact surfaces. After filtration and RO, treated effluent is commonly reused in cooling towers, boilers, utility and crate washing, toilets and gardening, while process water continues to meet IS 10500.
Which water quality standard applies to food processing water?
FSSAI requires potable water for use as an ingredient and for food-contact cleaning, and potable water in India is defined by IS 10500:2012. Packaged drinking water and mineral water units follow IS 14543 and IS 13428 under BIS certification.
How much does a food industry ETP cost?
As an indication, about ₹30 to 75 lakh for a 100 KLD aerobic plant and ₹80 lakh to 1.8 crore for a 250 KLD plant with an anaerobic reactor, for equipment and installation excluding civil works, land and taxes. The real figure depends mostly on COD and fat load, so we price after testing your effluent.
Why does my food ETP foam and smell?
Foam usually comes from CIP detergents or from filamentous bacteria that thrive on fats, and odour comes from sugars fermenting in unmixed sumps. Both are fixed at the cause: better fat removal, mixing and aeration in equalisation, and correct nutrient dosing.
Do you operate food industry ETPs?
Yes. We run ETPs under O&M contracts with trained operators, supply chemicals and spares, and provide monthly NABL-accredited test reports for your board and audits. We also take over and fix plants built by others.
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