SUEZ vs Ovivo MBBR/IFAS Equipment: Comparison & Best Fit

Introduction

For municipal and industrial wastewater engineers, the decision to implement Moving Bed Biofilm Reactor (MBBR) or Integrated Fixed-Film Activated Sludge (IFAS) technologies usually stems from a singular, pressing constraint: the need to increase biological treatment capacity within a fixed, often land-locked footprint. While the concept of biofilm carriers is well-established, the “commodity” perception of plastic media often leads to critical specification errors. The failure point in these systems is rarely the media itself; it is the integration of media retention (sieves/screens), aeration grids, and hydraulic profiles.

When evaluating market leaders, conducting a rigorous analysis of SUEZ vs Ovivo MBBR/IFAS Equipment: Comparison & Best Fit is a fundamental step for many design engineers. (Note: Following the acquisition of SUEZ Water Technologies & Solutions, these technologies are now largely under the Veolia umbrella, though the SUEZ brand and legacy product names like METEOR® remain ubiquitous in existing specifications and engineering archives).

These technologies are primarily utilized in activated sludge retrofits to achieve nitrification/denitrification (BNR) or in industrial pretreatment for high-rate COD removal. The operating environments are harsh; screens are subjected to constant abrasion, and aeration grids must manage the altered alpha factors caused by the media. Poor selection leads to catastrophic media washout, screen blinding requiring manual cleaning, or “dead zones” where media stagnates and fails to treat the wastewater.

This article provides a specification-safe, engineering-level breakdown to help you distinguish between the design philosophies of these two major manufacturers, calculate accurate loading rates, and specify the auxiliary components that determine long-term reliability.

How to Select / Specify

Selecting between major OEMs for biofilm processes requires moving beyond brochure surface area claims. Engineers must evaluate the entire reactor ecosystem. The following criteria define the engineering selection process for SUEZ vs Ovivo MBBR/IFAS Equipment: Comparison & Best Fit.

Duty Conditions & Operating Envelope

The primary driver for selection is the specific biological objective—typically nitrification or bulk BOD removal. Engineers must define:

• Temperature Profiles: Biofilm kinetics are temperature sensitive. In cold climates (< 10°C), the required Surface Area Loading Rate (SALR) changes drastically. Some retention screens are better suited for the aggressive mixing required to maintain biofilm thickness during cold-temperature dormancy.
• Hydraulic Peaking Factors: MBBR/IFAS systems place screens in the flow path. High wet-weather flows can cause excessive headloss across these screens. SUEZ and Ovivo offer different screen geometries (cylindrical vs. flat panel) that react differently to hydraulic surges.
• Variable Loading: Industrial applications with fluctuating COD loads benefit from systems that allow variable fill fractions (10-60%). The selected equipment must allow for easy media addition without requiring structural modifications to the retention sieves.

Materials & Compatibility

Read moreA Comparison Between Aerobic And Anaerobic Wastewater Treatment Technology

Biofilm carriers are generally High-Density Polyethylene (HDPE) or Polypropylene (PP), but the critical material selection lies in the retention sieves and aeration grids.

• Sieve Metallurgy: Stainless steel (304L or 316L) is the standard for retention screens. However, in high-chloride industrial applications or anaerobic zones, verify the corrosion allowance. Wedge wire construction is common, but the wire profile affects the propensity for stapling (fibers getting stuck).
• Media Wear: Cheap media abrades quickly, creating microplastics and losing active surface area. Specify virgin HDPE with a verified crush strength. Recycled plastics often lack the structural integrity for the 20-year design life required by municipal specs.

Hydraulics & Process Performance

The introduction of media changes the hydraulic gradeline (HGL) of the plant. Selection must account for:

• Headloss Constraints: Sieves add headloss. If the plant has limited hydraulic profile available (e.g., gravity flow through the secondary treatment), the “open area” of the screen becomes the deciding factor.
• Mixing Energy: To keep media in suspension, specific mixing energy densities (W/m³) are required. In IFAS zones, the aeration air often provides this mixing. In anaerobic/anoxic MBBR zones, mechanical mixers are required. The mixer blade design must be “media-safe” (propellers with backswept blades or slow-speed mixers) to prevent grinding the media.

Installation Environment & Constructability

Retrofitting an existing basin is vastly more complex than a greenfield build.

• Basin Geometry: Long, narrow plug-flow basins are challenging for MBBR because media tends to migrate to the effluent end. Systems that utilize multiple stages with intermediate baffles (a common SUEZ design approach) can mitigate this but require more complex concrete work.
• Access Hatches: Media retention sieves will eventually require maintenance. Designs that allow screen removal without draining the basin (slide rails) are preferable for plants without redundant trains.

Reliability, Redundancy & Failure Modes

The two most common failure modes in these systems are media washout and screen blinding.

• Media Washout: Occurs when screens breach or seals fail. Specify double-welded screens and rigorous seal testing (dye testing or feeler gauge inspections) during installation.
• Screen Blinding: Occurs when biofilm sloughs off too rapidly or rags accumulate. Air knives or scouring systems integral to the screen assembly are mandatory. Compare the air demand of the cleaning systems between manufacturers; this is a parasitic load that increases OPEX.

Read moreAqua-Aerobic vs WesTech for Filtration: Pros/Cons & Best-Fit Applications

Controls & Automation Interfaces

While the biological process is passive, the support systems are active.

• Air Scour Cycles: If using intermittent air scouring for screens, the PLC logic must be robust.
• DO Control: Dissolved Oxygen control in IFAS systems is complex because the biofilm layer creates a diffusion resistance. DO setpoints are typically higher (2.0-3.0 mg/L) than conventional activated sludge. The blower control PID loops must be tuned to account for the dampening effect of the media.

Maintainability, Safety & Access

Operators frequently cite screen cleaning as a primary frustration.

• Ergonomics: Are the air sparge manifolds accessible from the walkway?
• Confined Space: Does screen maintenance require entering the basin? Designs that mount screens to the wall with top-access guides are superior to floor-mounted screens for O&M safety.

Lifecycle Cost Drivers

Total Cost of Ownership (TCO) analysis must include:

• Aeration Efficiency (Alpha Factor): Media in the water interferes with bubble coalescence and rise time. MBBR/IFAS alpha factors are typically 0.60-0.75, lower than clean water or standard MLSS. This results in larger blower sizing and higher electrical costs.
• Media Replacement: While media theoretically lasts 20 years, assume a 1-2% annual top-up rate due to attrition or minor spills.
• Screen Cleaning Labor: Quantify the man-hours required for manual screen spraying if the automatic scour fails.

Comparison Tables

The following tables provide a direct technical comparison to assist in the “SUEZ vs Ovivo MBBR/IFAS Equipment: Comparison & Best Fit” analysis. Table 1 focuses on the OEM approaches, while Table 2 outlines application suitability.

Engineer & Operator Field Notes

Real-world experience often diverges from the design software outputs. The following notes are compiled from field observations regarding SUEZ and Ovivo installations.

Commissioning & Acceptance Testing

The Site Acceptance Test (SAT) is the most critical phase for MBBR/IFAS systems.

• Clean Water Testing: Before adding media, run the hydraulic test with clean water to verify screen seals. Use a dye tracer or physical probing around the screen frame to ensure no gaps exist larger than 50% of the media’s smallest dimension.
• Media Wetting: HDPE is naturally hydrophobic. New media floats excessively and takes 2-4 weeks to develop a biofilm and reach neutral buoyancy. During this period, verify that the “raft” of floating media doesn’t overtop the basin walls or block the overflow weirs.
• Mixing Verification: Perform a “dead zone” analysis. Visually inspect corners and floor areas. If media is piling up, the aeration grid or mixer orientation must be adjusted immediately before biology takes hold.

Common Specification Mistakes

• Ambiguous Media Specs: Specifying “generic MBBR media” allows contractors to source low-quality carriers. Specify “Virgin HDPE with specific gravity 0.94-0.96 and guaranteed crush strength >X lbs.”
• Ignoring Alpha Factors: Using standard fine-bubble alpha factors (0.5-0.8) for IFAS design will result in undersized blowers. Media shearing creates different bubble dynamics. Consult the specific OEM (SUEZ or Ovivo) for their empirical alpha factor curves based on fill fraction.

O&M Burden & Strategy

Operational strategy shifts significantly from conventional activated sludge.

• Screen Maintenance: High-pressure washing of screens is typically required annually or semi-annually, even with air scour systems. Design walkways to allow easy access to the screen face.
• Media Patterns: Operators should log the visual movement of the media daily. “Sluggish” movement indicates over-growth (thick biofilm) or insufficient aeration. This is often the first sign of an impending process upset.
• Foam Management: MBBR systems, particularly during startup, generate significant foam. Surface sprayers or defoamant dosing points should be included in the design.

Troubleshooting Guide

Symptom: Media piling up at the effluent screen.
Root Cause: Longitudinal flow velocity exceeds the mixing roll velocity.
Fix: Increase aeration at the effluent end (creating an “air curtain”) or install baffles to break the hydraulic short-circuit.

Symptom: Loss of Nitrification.
Root Cause: Biofilm is too thick (anoxic deep layer) or too thin (excessive scouring).
Fix: Adjust aeration scour intensity. Thick biofilm needs more scour; thin biofilm needs less. Check pH/Alkalinity.

Design Details / Calculations

When engineering the SUEZ vs Ovivo MBBR/IFAS Equipment: Comparison & Best Fit, the math must support the equipment selection.

Sizing Logic & Methodology

The core sizing parameter is the Surface Area Loading Rate (SALR), expressed in g/m²·day (grams of substrate per square meter of protected surface area per day).

Step 1: Determine Required Surface Area

Required Surface Area (m²) = (Load in g/day) / (Design SALR in g/m²·day)

Typical SALR values (at 15°C):

• Nitrification (Tertiary): 0.5 – 1.2 g NH4-N/m²·day
• Nitrification (IFAS combined): 0.8 – 1.5 g NH4-N/m²·day
• BOD Removal (High Rate): 5.0 – 20.0 g BOD/m²·day

Step 2: Calculate Media Volume

Media Volume (m³) = Required Surface Area (m²) / Specific Surface Area of Media (m²/m³)

Note: Use the “Protected Surface Area” value, not total area. Typical protected area is 500-800 m²/m³.

Step 3: Check Fill Fraction

Fill Fraction (%) = Media Volume / Reactor Volume

Ensure the fill fraction is within limits (typically 30-65%). If >65%, mixing becomes impossible. If <20%, the economics may favor a larger tank or different process.

Specification Checklist

Ensure these items are in your Division 46 specification:

• Media Retention Sieves: 316L SS, wedge wire, designed for [X] MGD peak flow with max [Y] inches headloss.
• Media Carriers: Material certification, dimension verification, and abrasion testing results (ASTM).
• Aeration Grids: Retrievable vs. Fixed capability. 304L SS piping minimum.
• Performance Bond: Require a process guarantee for the specific effluent parameters (e.g., NH3-N < 1.0 mg/L at [X] temperature).

Standards & Compliance

Reference applicable standards such as:

• Ten States Standards: For general redundancy and safety factors.
• ASTM D-Specific: For plastic density and tensile strength testing.
• ISO 11200: Noise standards for blowers associated with the high-pressure air requirements.

Frequently Asked Questions

What is the primary difference between MBBR and IFAS?

The primary difference is the presence of Return Activated Sludge (RAS). MBBR (Moving Bed Biofilm Reactor) is a once-through flow system where all biomass is attached to the carriers; there is no sludge recycling. IFAS (Integrated Fixed-Film Activated Sludge) is a hybrid system that combines suspended growth (MLSS) with biofilm carriers. IFAS is typically used to add nitrification capacity to existing activated sludge plants without increasing basin volume.

How do SUEZ and Ovivo differ in media retention technology?

While both offer robust solutions, the distinction often lies in the screen geometry. SUEZ (Metor) systems frequently employ cylindrical sieve assemblies that utilize vortex shedding to stay clean, often mounted on manifolds. Ovivo offers flexible designs, including flat panels and cylindrical screens, often tailored to specific basin geometries. The choice in the “SUEZ vs Ovivo MBBR/IFAS Equipment: Comparison & Best Fit” often comes down to hydraulic constraints; cylindrical screens can sometimes offer better open area in tight footprints.

What is the typical lifespan of MBBR media?

High-quality virgin HDPE media has a design life of 15 to 20 years. However, physical attrition (wear) can reduce the effective volume by 1-2% per year. It is common practice to top up the media volume every 3-5 years to maintain the design surface area. Inferior recycled media can become brittle and fracture much sooner, causing screen blockage.

How does cold water affect MBBR/IFAS sizing?

Nitrifying bacteria activity drops significantly below 12°C. Sizing must be based on the minimum monthly temperature. At 8°C, the required surface area (and thus media volume) may be 2x or 3x higher than at 20°C. Engineers must verify the “Design SALR” at the minimum temperature, not the average.

Why is headloss a critical factor in selection?

Adding retention screens to a basin acts as a hydraulic bottleneck. In gravity-flow plants, there may only be inches of freeboard available before backing up the upstream processes. SUEZ and Ovivo screens have different headloss curves. Selection must ensure that at Peak Hourly Flow (plus a blinding factor), the water level does not overtop the basin walls.

What happens if the aeration system fails?

In an MBBR/IFAS, aeration provides both oxygen and mixing. If aeration fails, the media will float to the surface (or sink, depending on biofilm thickness/density) and pack together. This creates anaerobic conditions rapidly and can structurally stress the retention screens or overflow weirs. Redundant blowers and standby power are critical for these systems.

Conclusion

In the final analysis of SUEZ vs Ovivo MBBR/IFAS Equipment: Comparison & Best Fit, there is no single “winner” for every application. SUEZ (Veolia) brings massive global install base data and highly standardized, robust sieve designs (METEOR) that function exceptionally well in large-scale municipal retrofits where reliability is paramount. Ovivo typically offers agility and customization, making them a strong contender for projects with unique geometries, industrial variability, or where specific media types are preferred.

For the design engineer, the path to success involves rigorous specification of the “unsexy” components: the retention sieves, the scour systems, and the hydraulic profile. By focusing on the interface between the media and the mechanical equipment, rather than just the plastic carriers themselves, you ensure a facility that meets discharge permits and remains operable for decades.