Dairy and Food Processing Wastewater Rules

Most dairy plants and food processing units in India need consent from the State Pollution Control Board under the Water Act, and must treat their wastewater before it goes into a drain, a sewer or onto land. Milk, whey, fruit pulp, starch and cooking oil are not toxic, but they rot fast and strip oxygen from water, so the board treats them as serious pollutants. The consent order sets the limits, the treatment plant and the disposal route. Very small units may fall in the green or white category, but the only safe way to know is to check the current category list for your process and size.

This guide is written mainly for owners and managers of milk plants, paneer and ghee units, ice cream makers, fruit and vegetable processors, edible oil units and parboiling rice mills. It covers consent, the category question, what the treatment plant has to handle, whey, sludge and records. It also has a section for neighbours dealing with smell, flies and white or sour water in the drain.

For the general legal framework on factory effluent, see industrial water pollution remedies. If your plant is already in trouble because the treatment system is down, read the legal risks of a non-working ETP.

The essentials

Does a dairy plant or food processing unit need pollution board consent?

In most cases, yes. Section 25 of the Water Act requires consent from the State Board before any industry, operation or process discharges trade effluent, and section 21 of the Air Act requires consent for units with boilers, fryers or other air emissions. A milk chilling and processing plant, a paneer or ghee unit, an ice cream factory, a fruit pulp or pickle unit, an edible oil refinery and a rice mill with parboiling all generate wastewater, and most of them run a boiler. So they need consent to establish before they build and consent to operate before they run.

The exception is units in the white category, which are exempt from consent, and in some states very small green category units whose consent process is lighter or replaced by registration. The categories depend on the process and the scale, and CPCB's lists have been revised over the years. Recent amendments and notifications have also changed consent requirements in places. Do not rely on what a neighbour was told five years ago: check the current list for your exact activity, and read our guide on red, orange, green and white categories.

Cattle dairy farms and gaushalas are a separate story. CPCB has issued guidelines on dung, urine and wash water management for them, and several states now regulate farms above a certain herd size. A farm with a few animals is not a factory, but a large commercial dairy farm next to a canal is expected to manage its waste.

Why milk and food wastewater counts as serious pollution

Milk, whey, sugar syrup, fruit pulp and starch are food, which is exactly the problem. Bacteria in a drain or pond feed on them and use up the dissolved oxygen in the water. A small amount of milk wash water in a big river does little harm. A daily discharge from a 50,000 litre milk plant into a village drain turns it grey, sour-smelling and fly-infested within a week, and kills whatever lived in the pond at the end of it.

Dairy wastewater also carries fat, which clogs drains and sewers, and cleaning chemicals. Clean-in-place systems use caustic soda and acid to wash tanks and pipelines, so pH swings sharply over the day. Fruit and vegetable units add peel, soil and sometimes brine. Pickle units produce very salty water that ordinary biological treatment struggles with. Parboiling rice mills release soaking water that is dark, warm and loaded with organic matter, and it smells strongly once it sits.

None of this is hazardous waste in the legal sense, and owners sometimes conclude it does not matter much. The board sees it differently, because the effect on a stream or pond is the same as any other high-strength effluent.

Typical wastewater problems in each kind of unit

Use this as a starting point when talking to your ETP designer or consultant. The consent order sets the binding limits.

What the consent order will ask of your wastewater

The consent order is the document that binds you. It will state the quantity of effluent allowed per day, the parameters it must meet (usually pH, BOD, COD, suspended solids and oil and grease), the treatment units you have said you will install, and where the treated water can go. The limits differ by disposal route: discharge into a public sewer connected to a sewage treatment plant, into a drain or stream, or onto land for irrigation. General standards are set in the schedules to the Environment (Protection) Rules 1986, and the board can impose stricter ones.

Using treated water to irrigate your own land or a nearby farm is common and can be a good solution, but only if the consent allows it and the water meets the land-disposal limits. Spreading effluent on land during the monsoon, when it simply runs off into the nearest drain, is a frequent cause of complaints. Some boards ask for storage for rainy days or for a green belt of a specified size.

If you intend to send treated water into the municipal sewer, you will usually also need the local body's permission. The board's consent and the municipality's permission are separate, and having one does not cover the other.

Why dairy and food ETPs fail, and how to avoid it

The most common reason is undersizing. Plants are designed for average flow, then the unit expands, or the milk flush season arrives, or Diwali orders triple sweet production, and the plant is overloaded. Biological systems cannot be rushed. When they are overloaded the effluent comes out barely treated, and the operator often opens the bypass.

The second reason is fat. A dairy ETP without a good fat trap or dissolved air flotation unit gets coated with grease, aeration fails and the plant smells. The third is pH shock from CIP chemicals dumped all at once, which kills the bacteria in the biological stage. The fourth is people: one untrained operator on a shift, no lab testing, and a manager who sees the ETP as a cost centre.

A well-run food plant ETP has an equalisation tank large enough to even out the day's flow, fat removal, a biological stage (often anaerobic followed by aerobic for strong dairy effluent), clarification and sludge handling. It runs on its own electricity meter, so its running hours can be shown. Boards increasingly compare power consumption of the ETP with production records to see whether the plant is actually being run.

What to do with whey, the biggest single mistake

Never put whey into the drain. Whey from paneer, chhena and cheese making carries a far higher organic load than ordinary dairy washings, and a small unit draining a few thousand litres of whey a day can do more damage to a pond than a large milk plant with a working ETP. It is also the item inspectors look for first, because the sour smell gives it away.

Whey has uses. Large plants dry it into powder or use it in beverages. Smaller units sell it to cattle owners as feed, use it in biogas plants, or send it to a larger plant under an arrangement. Each of these needs a record: who took the whey, how much and when. If none of these options is available, whey has to be accounted for in your treatment design, which usually means a much bigger biological stage than the consultant first proposed.

When a board inspector asks how whey is handled and the answer is vague, expect a show-cause notice.

Boilers, sludge and food waste: the other half of the consent

Wastewater gets the attention, but a food unit's consent usually covers air and solid waste too. Most dairies and food plants run a boiler for steam, often fired on husk, wood, briquettes or coal. That needs consent under the Air Act, a chimney of the height the board prescribes and, depending on size, a dust collector. Black smoke from a paneer unit's boiler at dawn is as much a breach as white water in the drain, and neighbours often complain about both together.

ETP sludge, screenings from fruit processing, spoiled product and peel all have to go somewhere lawful. Under the Solid Waste Management Rules 2026, bulk waste generators have their own duties for segregation and processing, and dumping on vacant plots or burning it is not allowed. Sludge from a food ETP can often be composted or dried and used as manure, but keep a record of where it went. Advocate B.K. Singh's usual advice to food unit owners is to treat the sludge register with the same care as the sales register, because it is the first thing an inspector asks for after the ETP logbook.

Setting up wastewater compliance for a new dairy or food unit

Follow this order. Units that build first and apply later spend more and face penalties under the consent rules.

For a deeper look at the paperwork, see documents needed for consent to operate and groundwater NOC exemptions.

Records a food or dairy unit should keep ready

A milk plant or food unit is making our drain stink. What can we do?

Complain in writing to the regional office of the State Pollution Control Board. Describe what you see and smell, when it happens, and where it enters the drain or pond. White or grey water, a sour or rotting smell, foam, fat lumps along the drain edge and swarms of flies are all signs of untreated dairy or food effluent. Photograph the outlet if you can see it, and note the times, because many units discharge at night or after washing at the end of a shift.

File an RTI asking whether the unit has consent to operate, what its effluent limits and disposal route are, and when it was last inspected. If the unit has no consent at all, the complaint becomes much stronger. If it discharges into the municipal sewer and the sewer is overflowing, copy the municipal corporation or jal board too. Our guide on complaining about untreated effluent covers the escalation steps.

Smell alone, without visible discharge, is harder. Note the times, the wind direction and how long it lasts, and ask the board to inspect the ETP and the sludge yard, which are common odour sources.

What happens when the board inspects a food unit

An inspector will usually look at the consent and its validity, walk the ETP, check whether each unit is running, look for a bypass pipe or a hose leading to the drain, take a sample at the outlet, and ask for the logbook, lab reports and whey and sludge records. Where production has grown since the consent was issued, expect questions on whether the ETP has kept pace.

If the sample fails or the records are missing, the board issues a show-cause notice and can follow with a closure direction under section 33A of the Water Act, disconnection of electricity and water, environmental compensation under the CPCB method, or a bank guarantee. In dairy matters Advocate B.K. Singh has handled, the units that came through a notice without closure were the ones that could produce a working ETP on the day of the follow-up inspection, with three months of genuine logbook entries behind it. Promises in a reply letter count for far less than a running plant.

Food safety licences under the Food Safety and Standards Act are a separate matter dealt with by the food safety department. A valid food licence does not answer a pollution notice, and a valid consent does not answer a food safety inspection.

Units in food parks and industrial estates

Units in a food park or industrial estate often send their effluent to a common effluent treatment plant instead of running a full ETP of their own. That does not remove responsibility. Each unit must still meet the inlet standards the common plant sets, which usually means pre-treatment for fat and solids, and must pay for and record the volume it sends. If the common plant fails, the board can act against the members as well as the operator. Read CETP compliance explained before relying on a common plant.

Units in a cluster also face cumulative scrutiny. Where several food units discharge into one drain, residents' complaints tend to name all of them, and the board may sample each outlet to see who is responsible. Good individual records are what separate a compliant unit from its neighbours.

Owner's checklist for dairy and food wastewater

Where to go from here

If you have already received a notice, read responding to a pollution board notice. If you are running without consent and want to regularise, see penalties for operating without consent. Meat processing has its own rules, covered in slaughterhouse pollution rules and complaints.