London Dairy (IFFCO International)
The Challenge
Two Simultaneous ETP Failures — Foul Odour and an Underperforming MBR at a Premium Ice Cream Plant
London Dairy is a premium ice cream brand manufactured by Seville Products (LLC) in Dubai under IFFCO International — one of the UAE's most recognised frozen dessert brands, distributed across 30+ countries with a range spanning premium ice cream, gelato, and frozen yoghurt. The manufacturing operations generate highly concentrated process wastewater from dairy ingredient processing, cream and milk handling, flavouring and additive preparation, and equipment cleaning-in-place — a wastewater characterised by extremely high COD (up to 15,000 mg/L design), very high fat, oil, and grease content from dairy processing, and significant Extracellular Polymer Substrate (EPS) generated during the biological degradation of dairy proteins.
By December 2022, the ETP — a seven-stage treatment train comprising two equalisation tanks (EQT-1 and EQT-2), dissolved air flotation (DAF), Moving Bed Biofilm Reactor (MBBR), Activated Sludge Tank (AST), Membrane Bioreactor (MBR), and Sludge Holding Tank — was experiencing two interconnected and escalating operational failures. First, severe foul odour was being generated at the equalisation tanks, Sludge Holding Tank, and decanter area — with measured Hydrogen Sulphide (H₂S) concentrations of 54–69 ppm and Volatile Organic Compounds (VOC) of 12.0–20.5 ppm at ambient temperatures of 39°C and 46% relative humidity. Second, the MBR was unable to achieve its design throughput of 250 m³/day, constrained by membrane fouling that had reduced permeate flux from the design value of 75 LMH to 55 LMH — limiting actual output to 162 m³/day. London Dairy engaged Spans Envirotech to conduct a comprehensive troubleshooting assessment and deliver actionable recommendations.
Key Issues:
- !H₂S at 54–69 ppm and VOCs at 12.0–20.5 ppm measured at the equalisation and sludge areas — driven by anaerobic conditions in EQT-1 and EQT-2 where aeration blower capacity (750 m³/hr) was sufficient for mixing but inadequate for aerobic digestion of the high-strength incoming wastewater
- !Decanter filtrate routed back to the equalisation tanks, adding concentrated microbial matter and increasing EQT COD by 30% — from 9,304 mg/L at the inlet lifting sump to 12,083 mg/L after EQT-2 — and further driving anaerobic decomposition and H₂S generation
- !MBR membrane flux reduced from 75 LMH (design) to 55 LMH (actual) due to fouling from emulsified dairy fats and Extracellular Polymer Substrate (EPS) formed during biological degradation of dairy proteins — uniquely problematic in ice cream wastewater
- !Polymer and scum from the Decanter being recirculated back into the MBR biological circuit, compounding membrane fouling and reducing treatment capacity
- !High HRT of approximately 5 days in the Sludge Holding Tank — insufficient for aerobic stabilisation of the mixed raw and biological sludge, creating sustained anaerobic conditions and odour generation at the sludge handling area
- !MBR filtration cycle parameters not optimised — actual filtration cycles of 102/day versus 144/day design, reducing daily filtration time by approximately 5 hours and directly limiting permeate recovery
The Solution
Stage-by-Stage Diagnosis of Dual Failures — Root Causes Traced for Both Odour and MBR Underperformance
Spans Envirotech's troubleshooting assessment began with a structured data review covering May–November 2022 operating records — flow rates, COD profiles at each treatment stage, MBR membrane performance parameters, chemical consumption, and sludge management data. A COD mass balance through the treatment train revealed that the DAF was removing 73% of incoming COD as raw, undigested sludge — far above the typical 30% COD removal expected — indicating that the biological treatment upstream was not digesting organic matter as designed, and that a disproportionate fraction of the organic load was being captured as floating sludge rather than converted biologically. This raw sludge, routed to the Sludge Holding Tank, was the primary driver of both the odour and the compounding MBR fouling problem.
For odour control, Spans evaluated five technology alternatives — Wet Air Scrubbing, Biofiltration, Liquid Redox Technology, Solid Scavengers, and Carbon Adsorption — against parameters including H₂S removal efficiency, VOC and ammonia removal, land footprint, energy requirement, chemical supply, byproduct management, capital cost, and operational complexity. Wet air scrubbing and biofiltration were recommended as the most suitable approaches for the facility's contamination profile, with a two- or three-stage design and turnkey procurement advised. For MBR recovery, immediate operational interventions were identified: optimising the filtration cycle time (reduced from 845 seconds to 785 seconds per cycle during the assessment visit via the SCADA system), segregating DAF scum and sludge from MBR biological sludge in separate decanter streams, stopping recirculation of decanter polymer and scum to the MBR tank, and maintaining MLSS within the design range of 8,000–12,000 mg/L. A comprehensive monitoring protocol — covering daily and weekly measurement schedules for all seven treatment stages — was delivered to the London Dairy operations team.
Technologies Deployed:
Implementation Timeline:
Phase 1: Multi-Stage Performance Data Review & Mass Balance
Reviewed May–November 2022 operating records and compiled a COD mass balance across all seven treatment stages. Identified 30% COD increase across equalisation tanks (from decanter filtrate routing), 73% COD removal at DAF (indicating raw sludge capture rather than biological conversion), and quantified MBR as the hydraulic bottleneck at 162 m³/day actual versus 250 m³/day design.
Phase 2: Odour Source Identification & Measurement
Measured ambient H₂S (54–69 ppm), ammonia (12–15 g/m³), and VOC (38.6–66.1 mg/m³) concentrations at the odour-generating areas. Traced root causes to three interacting factors: insufficient aeration for aerobic digestion in equalization tanks, decanter filtrate addition furthering anaerobic decomposition, and long HRT in the Sludge Holding Tank.
Phase 3: Odour Control Technology Evaluation
Evaluated five odour control technologies against a comprehensive comparison matrix including removal efficiency for H₂S, VOC, and ammonia, land footprint, energy, chemical requirements, byproducts, and capital/operational cost. Recommended wet air scrubbing or biofiltration as turnkey solutions, with two/three-stage design and vendor shortlist provided.
Phase 4: MBR Recovery Protocol & Monitoring System
Identified MBR fouling root cause as emulsified dairy fats and EPS from dairy protein degradation — unique to ice cream wastewater. Adjusted MBR filtration cycle time via SCADA during the assessment visit. Delivered a stage-by-stage monitoring schedule (daily/weekly parameters for all 7 stages), jar test protocol for chemical dosing optimisation, and data recording guidelines for trend analysis.
The Results
Engineering Depth Across a Seven-Stage ETP with Dual Failure Diagnosis
7 Stages
Diagnosis Coverage
Full treatment train assessment from equalisation through MBR to sludge dewatering — with COD mass balancing, hydraulic flow analysis, and sludge characterisation at each stage to locate where treatment efficiency was being lost
3 Measured
Odour Compounds
H₂S (54–69 ppm), Ammonia (12–15 g/m³), and VOCs (38.6–66.1 mg/m³) quantified on-site — root causes traced to three interacting process failures in equalization and sludge handling rather than a single point source
5 Evaluated
Technology Options
Wet air scrubbing, biofiltration, liquid redox, solid scavengers, and carbon adsorption assessed against a multi-parameter comparison matrix — wet scrubbing and biofiltration recommended as turnkey two/three-stage solutions
Identified
MBR Root Cause
MBR flux loss traced to emulsified dairy fat and Extracellular Polymer Substrate (EPS) from dairy protein degradation — a fouling mechanism specific to ice cream wastewater requiring segregated sludge handling and cycle time management
SCADA Optimised
Immediate Fix
MBR filtration cycle adjusted from 845 to 785 seconds per cycle via SCADA during the assessment visit — an immediate operational improvement increasing filtration cycles per day without capital expenditure
Dubai Standards
Monitoring Basis
Stage-by-stage monitoring schedule, jar test protocols, and data recording guidelines delivered to the London Dairy operations team — structured against Dubai Municipality compliance requirements for ongoing plant management
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