CPCB Schedule VI: General Standards for Food Industries
The regulatory framework for effluent discharge from food and beverage industries in India is primarily set by the Environment (Protection) Rules, 1986, which prescribes General Standards (Schedule VI) and allows CPCB to publish industry-specific Minimal National Standards (MINAS). State Pollution Control Boards are empowered to set stricter standards in individual Consent to Operate (CTO) conditions but cannot set standards more lenient than the national standards.
Schedule VI general standards for discharge to inland surface water (rivers, lakes, streams):
- pH: 6.5–9.0
- BOD (3-day, 27°C): ≤30 mg/L
- COD: ≤250 mg/L
- TSS: ≤100 mg/L
- Oil and grease: ≤10 mg/L
- Total dissolved solids: ≤2,100 mg/L (≤500 mg/L for some sensitive river stretches)
- Temperature: ≤40°C at discharge point
- Ammonia (as N): ≤50 mg/L (applies to food industries with significant protein content)
The BOD test method specified — 3-day at 27°C — reflects Indian laboratory conditions and gives slightly different results from the internationally standard 5-day BOD at 20°C (BOD₅). Indian BOD₃ at 27°C approximates to roughly 65–70% of BOD₅ for typical food wastewater. When comparing Indian standards with European or US standards, adjust for this methodological difference.
The COD standard of ≤250 mg/L is the critical design parameter for ETP sizing in food industries. With typical food industry inlet COD of 3,000–15,000 mg/L, this represents 98–99% COD removal. Achieving this consistently — not just on good operating days — requires a robust ETP design with adequate buffer capacity and appropriate technology selection.
For a detailed discussion of food industry wastewater characteristics by sub-sector, see the food industry wastewater characteristics guide.
Industry-Specific MINAS Standards
CPCB has published separate MINAS for several food and beverage sub-sectors. These are incorporated into CTO conditions by SPCBs and may be supplemented with additional parameters:
Dairy Industry
MINAS for dairy processing (milk chilling plants excluded): BOD ≤30 mg/L; COD ≤250 mg/L; TSS ≤100 mg/L; oil and grease ≤10 mg/L; pH 6.5–9.0. No specific TKN or phosphorus standard in the national MINAS, but SPCB CTO conditions in some states (Maharashtra, Karnataka) add TKN ≤50 mg/L for larger units. CIP (clean-in-place) caustic and acid flows must be neutralised before entering the ETP — pH swings of pH 1–13 from CIP are toxic to biological treatment.
Slaughterhouses and Meat Processing
BOD ≤30 mg/L; COD ≤250 mg/L; TSS ≤100 mg/L; oil/grease ≤10 mg/L; TKN ≤50 mg/L. The TKN standard is particularly relevant for blood-containing streams — blood has BOD equivalent to approximately 500 times its volume of typical sewage. Blood segregation and recovery as a commercial by-product (blood meal, fertiliser) dramatically reduces both BOD and TKN load on the ETP. Fecal coliform standards are also applied by some SPCBs for slaughterhouse effluent near water bodies.
Sugar Mills
Juice and wash effluent: BOD ≤30 mg/L; COD ≤250 mg/L; TSS ≤100 mg/L. Spent wash (molasses fermentation residue for distilleries co-located with sugar mills): subject to the separate ZLD mandate for distilleries. Sugar mills must also comply with cooling water discharge standards (temperature ≤40°C). See the ETP for sugar refinery guide for process design considerations.
Seafood and Fish Processing
BOD ≤30 mg/L; COD ≤250 mg/L; TSS ≤100 mg/L; oil/grease ≤10 mg/L; TKN ≤100 mg/L. The strong odour from seafood processing effluent (trimethylamine and other volatile amines) is addressed through covered ETP design and biological treatment — not through a separate standard parameter. SPCB conditions for coastal seafood processing plants near estuaries may include a fecal coliform standard to protect shellfish growing areas.
Beverages and Packaged Food
No separate national MINAS exists for carbonated beverages, fruit juices, biscuits, confectionery, or packaged snack foods. Schedule VI general standards apply. In practice, SPCB CTO conditions for these units typically specify BOD ≤30 mg/L, COD ≤250 mg/L, pH 6.5–9.0, and oil/grease ≤10 mg/L for discharge to inland water, and BOD ≤350 mg/L for sewer discharge. For units located in industrial estates with a common ETP, pre-treatment standards set by the CETP management apply.
What BOD <30 mg/L Requires from Your ETP
The BOD ≤30 mg/L standard is frequently cited in CTO conditions and often misunderstood as straightforward. For food industries, the challenge is not achieving BOD <30 mg/L in optimal conditions — it is maintaining this standard consistently through seasonal production peaks, batch-process shock loads, CIP chemical surges, and monsoon weather.
Removal requirement calculation: A biscuit manufacturing unit with inlet BOD of 2,000 mg/L must achieve 98.5% BOD removal to meet 30 mg/L. A cheese plant with inlet BOD of 5,000 mg/L needs 99.4% removal. A fruit juice processor with BOD 8,000 mg/L during citrus season needs 99.6% removal. These are demanding removal efficiencies that leave no margin for operational lapses.
Required treatment stages for food industries:
- Screening and equalisation: Fine screening (2–3 mm) removes fibrous solids. Equalisation tank (8–16 hours of average flow) buffers BOD peaks — without equalisation, shock loads overwhelm biological treatment.
- pH correction: Food effluent is typically acidic (pH 3.5–6.5 from fermentation, fruit acids, CIP acid rinse). Biological treatment requires pH 6.5–8.5. Caustic soda dosing with in-line pH correction brings pH into range.
- Primary treatment (DAF or settlement): Dissolved Air Flotation removes fats, oils, and colloidal matter — 40–60% BOD removal. For high-fat dairy, poultry, and fish processing streams, DAF is essential before biological treatment. Settlement (primary clarifier) is used for settleable solids-rich streams (starch, potato, rice mill).
- Biological treatment (MBBR or activated sludge): Achieves 95–98% of remaining BOD. MBBR technology is preferred for food industries due to high biomass density (handling BOD peaks), compact footprint, and tolerance to intermittent operation. Activated sludge is viable for larger, consistent-flow units.
- Secondary clarification + polishing: Secondary clarifier with sludge return. Pressure sand filter + activated carbon filter brings outlet BOD to <30 mg/L consistently by removing residual particulates and adsorbing dissolved organics.
For high-strength streams above 3,000 mg/L COD (whey, spent yeast, fruit press water), adding UASB anaerobic pre-treatment before the aerobic stage reduces aeration energy by 60–70% and generates biogas. The UASB for food industry guide covers design thresholds and process considerations.
Sewer Discharge vs. Inland Water Discharge Standards
The standards applicable to your facility depend on where your ETP outlet discharges. There are three discharge modes with different standards:
Discharge to Inland Surface Water
Rivers, streams, canals, lakes — Schedule VI general standards apply: BOD ≤30 mg/L, COD ≤250 mg/L, TSS ≤100 mg/L. This is the most stringent discharge mode and requires a full secondary + tertiary treatment ETP.
Discharge to Public Sewer (Municipal System)
The pre-treatment standards for sewer discharge are set by CPCB and, at the local level, by municipal by-laws: pH 5.5–9.0; BOD ≤350 mg/L; TSS ≤600 mg/L; oil/grease ≤20 mg/L; temperature ≤45°C; no heavy metals above specified concentrations. These are significantly more lenient — enabling smaller ETPs with primary + partial secondary treatment. However, several caveats apply:
- Municipal sewer infrastructure in many Indian cities has limited capacity; large industrial discharges require NOC from the municipal authority (ULB/corporation) separately from SPCB CTO.
- Many municipalities have set stricter local by-law standards (BOD ≤250 mg/L, TDS ≤1,000 mg/L) to protect their STP and sewer infrastructure.
- High-TDS or high-temperature discharges (from CIP hot caustic or dairy pasteurisation) can damage sewer infrastructure; municipalities are increasingly restricting such discharges.
- SPCB CTO conditions sometimes require sewer discharge to meet the same standards as inland water discharge if the municipal STP itself is non-compliant or discharges to a sensitive water body.
Discharge to CETP
For units in industrial estates with a CETP, pre-treatment standards are set by the CETP management as inlet acceptance criteria. These typically align with CETP design basis — e.g., pH 6–9, BOD ≤1,000–2,000 mg/L, TDS within certain limits. The CETP takes responsibility for final treatment and discharge.
State SPCB Variations Beyond CPCB Standards
SPCB CTO conditions routinely set stricter standards than the national CPCB MINAS, particularly for food industries in ecologically sensitive or water-stressed regions. The key state variations:
GPCB (Gujarat)
GPCB frequently sets BOD ≤20 mg/L (rather than 30 mg/L) for food units in industrial estates near rivers. TDS ≤2,000 mg/L is commonly applied — relevant for dairy units with brine from brine-salting and for beverage units using softened water. ZLD may be required for large units in water-stressed GIDCs. See the GPCB ZLD guide for Gujarat-specific details.
MPCB (Maharashtra)
MPCB applies pH 6.5–8.5 (narrower than national 6.5–9.0) for food units near water bodies. Colour parameter (in ADMI units or platinum cobalt scale) is added for fruit/vegetable processing units generating visible colour. For units near Mumbai's coastal waters, mercury and other specific parameters may be added. The MPCB effluent standards guide covers Maharashtra-specific requirements in detail.
TNPCB (Tamil Nadu)
Tamil Nadu's TNPCB has historically applied strict TDS limits for units discharging near river systems affected by saline intrusion (Cauvery delta, Palar basin). Food units with significant brine or salt usage (fish processing, pickling, cheese) face TDS ≤1,000 mg/L conditions in some areas. Colour limits apply for beverages and natural food colouring units.
TSPCB (Telangana)
Temperature limits of ≤38°C (stricter than national 40°C) apply for units near Musi River. Fecal coliform standards are applied for food units discharging near areas used for agricultural irrigation with treated wastewater — ≤1,000 MPN/100 mL in some CTO conditions.
Monitoring Frequency and NABL Testing Requirements
Effluent monitoring requirements for food and beverage industries under SPCB CTO conditions are typically:
- Internal daily monitoring: pH (in-line or daily grab), flow volume, visual appearance. Most CTO conditions require daily ETP log records even if not specifically stated.
- Self-monitoring weekly or monthly: Using industry's own instruments or a local lab (not necessarily NABL) for BOD, COD, TSS at outlet. This gives operational feedback before formal NABL tests.
- NABL quarterly: Mandatory quarterly composite sample testing at NABL-accredited laboratory. The NABL lab's test report for all CTO parameters (BOD, COD, pH, TSS, oil/grease, and any additional CTO parameters) submitted to SPCB annually with Form V.
- Red-category food units (slaughterhouses, large dairy, large distilleries):OCEMS required for flow, pH, COD (online), TSS with data transmission to SPCB server. See the OCEMS installation guide for setup and calibration requirements.
Composite sampling (flow-proportional composite over 24 hours) rather than grab samples is the technically correct method for characterising food industry effluent, which varies significantly by time of day (morning CIP vs. afternoon production). NABL labs offering composite sampling services should be preferred for formal monitoring.
Selecting the Right ETP Technology for Compliance
Technology selection for food and beverage ETP compliance depends on inlet characteristics, discharge mode, available space, and budget. The following decision framework covers the most common food sub-sectors:
Dairy (Milk Processing, Cheese, Ice Cream)
DAF (with PAC coagulation at pH 6.0–7.0) → MBBR → PSF + ACF. For large integrated dairy plants with on-site boiler: UASB is viable above COD 3,000 mg/L inlet for energy recovery. CIP stream equalisation is mandatory to prevent pH shock to biological system. See the DAF for dairy wastewater guide.
Fruit and Vegetable Processing
Equalisation (oversized — 16–24 hours for seasonal operations) → pH correction → DAF → MBBR → PSF. Nutrient dosing (urea + DAP) is typically needed as food processing wastewater is nitrogen and phosphorus deficient. See the ETP for fruit juice processing guide.
Poultry, Meat, and Fish Processing
Blood segregation/recovery → DAF → Two-stage MBBR with nitrification-denitrification (TKN removal) → UV disinfection. Temperature is typically adequate for biological treatment. Peak morning load buffering via enlarged equalisation is important. See the ETP for poultry processing guide.
Sugar and Beverages
Cooling water segregation → Equalisation → MBBR → PSF. VFD aeration for load variation management. Sugar mills with associated distilleries need UASB for spent wash. See the ETP for sugar refinery guide and ETP for beverage manufacturing guide.
For a technical assessment of ETP design for your specific food or beverage operation — including inlet characterisation, treatment train selection, and sizing calculations —contact the Spans Envirotech engineering team. We have designed and commissioned ETPs for food and beverage industries across India including dairy, fruit processing, meat and poultry, bakery, beverages, and sugar, delivering consistent compliance with CPCB and SPCB discharge standards.