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The food and beverage sector in India processes over 50 million tonnes of produce annually, generating 5–10 litres of wastewater per litre of product—from dairy plants discharging 1,000–5,000 KL daily to breweries releasing 500–2,000 KL. This effluent carries high organic loads (BOD 1,000–5,000 mg/L), fats, oils, grease (FOG 200–1,000 mg/L), and suspended solids, threatening rivers and groundwater if untreated.
The best STP plant for food and beverage industry must handle fluctuating volumes, remove 95%+ pollutants, and enable water reuse while complying with stringent norms. SKF Elixer’s Vulcan STP with AABR and hybrid configurations excels in industrial wastewater treatment, delivering capacities from 15–1,000 KLD in stainless steel for durability and efficiency.
This blog examines wastewater traits, treatment hurdles, suitable technologies, AABR benefits, and regulatory adherence. Whether you operate a juice unit in Nashik or a snack factory in Indore, discover how tailored food processing effluent management safeguards operations and the environment.
Characteristics of Wastewater in Food & Beverage Units
High BOD and COD Levels
Biochemical Oxygen Demand (BOD) in dairy wastewater stems from lactose (40–50% of milk solids), proteins like casein, and fats, contributing 1,000–2,500 mg/L—equivalent to 100–250 grams BOD per litre processed. For a 100 KL milk plant handling 10,000 litres milk daily (10:1 wastewater ratio), this translates to 100–250 kilograms BOD discharged, demanding 100–250 kilograms oxygen for natural degradation if untreated.
Chemical Oxygen Demand (COD) doubles BOD at 2,000–5,000 mg/L due to non-biodegradable fractions like sanitizers. In fruit processing, pectin and sugars elevate BOD to 3,000–5,000 mg/L; a 200 KL juice unit loads 600–1,000 kilograms BOD daily. Untreated, 1 mg/L BOD depletes river dissolved oxygen by 1 gram per litre flow, creating hypoxic zones below 4 mg/L across 5–10 kilometres downstream, suffocating fish and macroinvertebrates.
Fats, Oils, and Grease (FOG)
Butter and cheese production releases 500–1,000 mg/L FOG from cream separation and whey; meat processing adds 300–800 mg/L from rendering. These non-polar lipids form stable emulsions with surfactants in CIP (clean-in-place) solutions, creating 5–10 cm thick scum layers in equalization tanks that reduce effective volume by 20–30% and inhibit oxygen transfer in aeration basins by coating diffusers—lowering efficiency 30–50%.
In a 200 KLD snack frying unit, 40–200 kilograms FOG daily clogs pumps and pipes, necessitating ₹50,000–₹1 lakh in annual repairs if not pre-removed via gravity traps or DAF units achieving 85–95% separation at 5–10% air recycle rates.
Suspended Solids (TSS)
Vegetable washing generates 500–2,000 mg/L TSS from soil, peels, and fibers—50–400 kilograms daily in 100 KLD operations. Bakery dough residues contribute 300–1,000 mg/L flour and starch particles.
High TSS increases turbidity to 500–2,000 NTU, shielding pathogens from UV disinfection and overloading clarifiers with hydraulic rates exceeding 2 m³/m²/hr, leading to carryover and effluent TSS >100 mg/L. In beverage bottling, label adhesives add 100–300 mg/L polymeric solids, requiring pre-screening with 1–2 mm mesh to prevent 20–30% media blinding in downstream biological units.
pH Fluctuations and Nutrients
Citrus juicing drops pH to 3–5 from citric acid; caustic soda cleaning raises it to 11–13. Extremes outside 6.5–8.5 kill nitrifying bacteria (optimum pH 7.2–7.8), halting ammonia conversion and spiking effluent NH3-N >50 mg/L.
Proteins yield 50–150 mg/L nitrogen; phosphates from additives 20–50 mg/L. A 200 KLD dairy plant discharges 10–30 kilograms nitrogen daily—fueling algal growth at 1:10 N:P ratio in receiving waters.
Temperature and Volume Variability
Pasteurization effluents exit at 40–60°C, raising mixed liquor above 35°C optimum and reducing microbial activity 50% per 10°C rise. Harvest seasons spike volumes 200–300% (e.g., mango processing from 100 to 300 KLD); shift cleaning adds 500–1,000 KL pulses.
Hot, variable flow shocks conventional systems, causing biomass washout and effluent BOD >200 mg/L.
Treatment Challenges and Process Requirements
Shock Organic Loads
Cleaning cycles release CIP solutions with 5,000–10,000 mg/L COD in 30–60 minute bursts—300–500% above average. Conventional activated sludge experiences filamentous bulking (SVI >200 mL/g), settling poorly and carrying over solids.
Equalization tanks with 6–12 hours HRT (hydraulic retention time) and aeration mixing at 0.5–1 m³ air/m³ tank volume homogenize loads, preventing biology failure.
FOG Emulsification
Surfactants stabilize oil droplets <50 microns, resisting gravity separation (removal <50%). Dissolved air flotation with polymer dosing (0.5–2 mg/L) achieves 85–95% FOG removal at 5–10% recycle, producing float sludge at 5–8% solids—critical to protect downstream media from coating and oxygen transfer loss.
Foaming and Odour
Detergents (100–500 mg/L) generate 1–2 metre stable foam in aeration, overflowing tanks and creating slip hazards. Anti-foam silicones (0.1–0.5 mg/L) collapse bubbles; enclosed systems with bio-scrubbers capture H2S (50–200 ppm from anaerobic pockets), converting to sulphates.
Sludge Bulking
Sugars favour filamentous organisms (e.g., Thiothrix); selector zones with high F/M ratio (>2 kg BOD/kg MLSS/day) suppress growth. Chlorination at 5–10 mg/L Cl2 controls filaments without harming overall biomass.
Water Reuse Stringency
Non-contact reuse (boiler, cooling) requires BOD <50 mg/L, FOG <10 mg/L, TDS <500 mg/L. Tertiary sand-anthracite filtration + activated carbon + UV (40 mJ/cm²) ensures compliance, recycling 90% flow.
Technologies Suited for Organic Load Management
Anaerobic Digestion (Pre-Treatment)
Upflow Anaerobic Sludge Blanket (UASB) or Continuous Stirred Tank Reactor (CSTR) reduces BOD 70–80% at loading 5–10 kg COD/m³/day, producing 0.3–0.5 m³ biogas per kg COD removed—equivalent to 30–50 litres diesel per m³ biogas at 60% methane.
A 200 KLD hybrid yields 300–500 m³ biogas daily, powering 75–125 kW generators for ₹1–1.5 lakh monthly savings. Post-anaerobic effluent BOD 300–600 mg/L requires aerobic polishing.
Aerobic Systems
Moving Bed Biofilm Reactor (MBBR) with 30–40% media fill achieves 90–95% BOD removal but suffers FOG coating, requiring quarterly cleaning. Sequencing Batch Reactor (SBR) handles batches flexibly but consumes 0.8–1 kWh/KL in cyclic aeration.
Hybrid AABR (SKF Elixer Vulcan)
Anaerobic pre-treatment + AABR aerobic stage: UASB drops 70% load; fixed media (200–300 sqm/cum) with fine bubble aeration polishes to <50 mg/L BOD total. FOG trap + DAF pre-removes 80–90%; energy 0.5–0.7 kWh/KL; sludge 0.4–0.6 kg/kg BOD.
Membrane Processes
Membrane Bio-Reactor (MBR) delivers BOD <5 mg/L but FOG fouls 0.1-micron membranes, necessitating chemical cleaning every 3–6 months (₹1–2 lakh replacement/5 years).
Benefits of Using AABR or Hybrid STP Systems
High Organic Removal Efficiency
AABR standalone achieves 95% BOD (<50 mg/L) via extended solids retention (15–20 days SRT); hybrid with UASB reaches <20 mg/L. A 200 KLD dairy treats 400 kg BOD to 8 kg daily—enabling boiler feed reuse after polishing.
FOG and TSS Handling
Integrated DAF with polymer removes 85–95% FOG (<50 mg/L) and 90% TSS; prevents media blinding and maintains oxygen transfer >30%. Eliminates ₹50,000 yearly anti-foam and cleaning.
Compact and Modular
Footprint 0.5–0.7 sqm/KLD (100–140 sqm for 200 KLD) vs. 1–1.5 sqm/KLD conventional—fits factory basements. Scale by ₹6–8 lakh per 50 KLD module.
Energy and Biogas Recovery
Hybrid generates 100–200 m³ biogas/day (200 KLD), offsetting 50–70% power; aerobic stage 0.5 kWh/KL = ₹50,000–₹70,000/year total vs. ₹1–1.5 lakh aerobic-only.
Low Sludge and Odour
30% less yield than MBBR; enclosed SS tanks + scrubbers eliminate H2S—compost 20–30 tonnes/year manure.
Water Reuse
90–95% recovery (180,000 litres/day from 200 KLD) for CIP—₹2–3 lakh monthly savings at ₹100/KL fresh water.
Compliance with FSSAI, PCB, and Environmental Standards
FSSAI Guidelines
Non-contact reuse: BOD <50 mg/L, FOG <10 mg/L—Vulcan hybrid delivers <20 mg/L BOD, <5 mg/L FOG via DAF + AABR.
PCB Effluent Norms
Food industry discharge: BOD ≤30 mg/L, COD ≤250 mg/L, pH 6.5–8.5—online OCEMS integration in Vulcan SCADA.
Zero Liquid Discharge (ZLD)
Optional RO on tertiary effluent recycles reject; ₹2–3/KL treated cost.
HACCP/ISO 22000
Food-grade SS304 construction + CIP-compatible design prevents cross-contamination; SCADA logs for audits.
CPCB Incentives
75% recycling qualifies for 20–30% CAPEX subsidy under EPR schemes.
Conclusion
The best STP plant for food and beverage industry tackles high BOD/FOG, variable loads, and reuse needs with hybrid anaerobic-AABR systems. SKF Elixer’s Vulcan delivers 95%+ removal, biogas recovery, and ₹2–3 lakh monthly savings in 200 KLD plants.
Choose proven food processing effluent management for compliance, cost control, and sustainability. Contact SKF Elixer today.
FAQs
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1. What makes food industry wastewater high in BOD?
Milk, sugars, proteins contribute 1,000–5,000 mg/L BOD (100–500 g/KL); 200 KLD dairy loads 200–1,000 kg BOD daily—requiring anaerobic pre-treatment to reduce 70–80% before aerobic polishing.
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2. How does FOG affect STP performance?
200–1,000 mg/L FOG forms emulsions, coating media and reducing oxygen transfer 30–50%; Vulcan’s DAF pre-removes 85–95% (<50 mg/L), preventing ₹50,000 yearly downtime.
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3. Why choose hybrid anaerobic-AABR for beverage plants?
Anaerobic digests 70% BOD + generates 0.3–0.5 m³ biogas/kg COD (₹1–1.5 lakh fuel savings monthly); AABR polishes to <20 mg/L—total energy 0.5–0.7 kWh/KL vs. 1–1.5 kWh/KL aerobic-only.
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4. What reuse standards apply to treated effluent?
FSSAI: BOD <50 mg/L, FOG <10 mg/L for non-contact; PCB: BOD <30 mg/L discharge. Vulcan hybrid achieves <20 mg/L BOD, enabling 180,000 litres/day CIP reuse in 200 KLD plant.
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5. How does stainless steel benefit food STP plants?
SS304 resists corrosion from pH 3–13 cleaning agents (20–25 year life vs. 10–12 years MS); prevents bacterial harborage—critical for HACCP compliance and ₹1–2 lakh repair savings every 5 years.
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