UK HQ Your time

Case Study: Dairy Effluent Treatment — DAF System

A large-scale UK milk processing facility faced increasing BOD load from expanded production. Reynolds & Bauhm designed and commissioned a DAF-based treatment train that achieved consent compliance within 12 weeks.

Dairy IndustryDAF SystemUKFood ProcessingBOD Reduction
98%BOD Removal
95%Fat & Protein Recovery
12 weeksTo Compliance
4,800 m³/dayPeak Flow

The Challenge

A dairy processing facility in the East Midlands producing fluid milk, cream, and cheese expanded throughput by 40%, pushing daily effluent BOD from 1,200 to 2,800 mg/L — far above their discharge consent of 250 mg/L BOD, 100 mg/L SS, and 50 mg/L fat. The existing dissolved air flotation unit was sized for the old production volume and was hydraulically overwhelmed during cleaning-in-place (CIP) peaks.

  • Peak flow: 4,800 m³/day including CIP returns
  • Feed BOD: 2,500–3,200 mg/L (average); 8,000–12,000 mg/L during CIP surges
  • Feed fat: 800–2,200 mg/L; protein 600–1,800 mg/L
  • Footprint constraint: no new civil works possible within 18-month timeline
  • Regulatory pressure: enforcement notice served by Environment Agency; three-month compliance deadline

The Solution

Reynolds & Bauhm completed a rapid site assessment and proposed a phased solution using our modular DAF platform to fit within the existing plant room footprint. The existing unit was retained as a duty standby for the first CIP equalisation stage.

  • Phase 1 (weeks 1–4): Installation of a 2,500 m³ equalization tank to buffer CIP surges, reducing peak load variation from ±4× to ±1.5× of average flow
  • Phase 2 (weeks 4–10): Commissioning of a new 250 m³/h dissolved air flotation unit with integrated coagulation and flocculation chambers; recycle ratio 30%; saturator pressure 5.5 bar
  • Polymer and coagulant optimisation: jar-testing programme identified polyamine coagulant at 80 mg/L + anionic polyacrylamide at 3 mg/L as optimal for fat/protein co-flotation
  • Recovered float cream (6–8% fat) directed to tanker collection for rendering — generating –annual output from previously discarded material
  • SCADA integration via our automation team for automated polymer dosing control based on inlet turbidity and pH

Process Train

StageEquipmentFunction
1Curved screen (1 mm aperture)Fibre and solid removal
22,500 m³ equalisation tank with mixerFlow and load balancing
3Rapid mix chamber with pH correctionpH 6.5–7.0; coagulant dosing
4Flocculation chamber (3-stage baffled)Floc growth; polymer dosing
5250 m³/h dissolved air flotation unitFat, protein, SS removal
6Float cream collection hopper → tankerBy-product recovery
7Sub-surface discharge monitoringBOD, SS, fat continuous measurement

Results Achieved

Consent Compliance

Discharge BOD achieved 35–60 mg/L (consent: 250 mg/L). SS: 18–35 mg/L (consent: 100 mg/L). Fat: <5 mg/L (consent: 50 mg/L). Enforcement notice withdrawn at week 14.

Operating Benefits

Reduction in trade effluent charges of. Cream recovery output of. Project benefits achieved within 26 months.

Future Capacity

DAF unit sized for further 25% production increase with no modification. Equalisation volume provides headroom for extended CIP cycles during cleaning campaigns.

Rapid Commissioning & Operator Training

Complete commissioning within 4 weeks including hands-on operator training, SOP documentation, and performance guarantee sign-off.

Related Pages

Dairy Industry

Wastewater treatment solutions for milk, cheese, yoghurt, and dairy processing facilities.

Dairy Industry

DAF Systems

Our dissolved air flotation range for food processing and industrial wastewater.

DAF Systems

DAF Sizing Calculator

Estimate DAF surface area, recycle flow, and A:S ratio for your application.

Use Calculator

Discuss Your Project

Our engineers are available to review your site conditions and recommend the most appropriate treatment solution.

Industries We Serve

Our expertise spans multiple industries with sector-specific water treatment solutions.