AEROSTRIP® Aerators

Advanced perforation technology and a high strength polyurethane membrane are the secrets to the AEROSTRIP® fine pore diffusers high performance and long service life. Ovivo guarantees clean water transfer efficiencies of 8.5-10%/m (2.6-3.0% ft) side-water depth (SWD) in virtually all applications.
  • Highest proven oxygen transfer efficiency in the world
  • Longest service life on the market
  • Online maintenance with flexible diffuser operation
  • No dead zones

Aeration accounts for about 50% of a wastewater treatment plant’s energy bill and can consume significant maintenance resources to maintain performance. Reducing these operational costs while meeting today’s stringent permit limits is imperative for municipalities and industries today. AEROSTRIP® diffusers have been the leading technology to reduce operational costs and improve plant performance since 1996 with over 1,000 worldwide installations (over 60 in the United States).

  • Guaranteed standard oxygen transfer efficiency (SOTE) up to 10%/m (3%/ft) SWD
  • Membrane service life of 10 – 15+ years while maintaining peak perfromance
  • Perforation allows for intermittent operation and an automatic flex cleaning cycle
  • Evenly-spaced, floor mounted diffusers use the entire process volume

AEROSTRIP® diffusers use polyurethane membranes mounted on PVC or stainless steel bases. The membrane material offers about three times the strength of conventional EPDM membranes with less than one-third the thickness. The result is a long-lasting diffuser that retains its performance characteristics over many years.

AEROSTRIP diffusers can handle an operational flux range between 5 – 120 Nm3/m2/hr (0.3 – 7.1scfm/ft2), the widest range in the industry. In addition, AEROSTRIP diffusers are perfectly suited for intermittent operation without plugging or fouling of the pores. AEROSTRIP diffusers have been used extensively in SBRs, MBRs and industrial applications, as well as conventional activated sludge facilities.

Our floor mounted system makes for easy installation with many facilities opting to install the systems themselves. Upgrading their facilities with an AEROSTRIP system has allowed plant operators to save up to 50% on their energy bills, eliminate dead zones in their basins and eliminate much of their maintenance burden in favor of our online system.

Membrane:
The AEROSTRIP® diffusers are manufactured with a polyurethane membrane. Unlike EPDM membranes, polyurethane membranes have no softeners or plasticizers to leach into wastewater over time (the reason EPDM membranes require frequent replacement). AEROSTRIP diffuser membranes are proven to last 15+ years without replacement.

Perforation:
The advanced Austrian perforation technology and the thin membrane profile allow small bubbles to form without significant membrane fouling over time. The result is the highest guaranteed, proven, long-term oxygen transfer efficiency of any diffuser in the world. Perforation allows for a wide operational flux range of 5-120 Nm3/m2/hr (0.3-7.1 scfm/ft2) for every diffuser.

Assembly:
AEROSTRIP membranes are assembled onto either a stainless steel (“T” Type) or PVC (“Q” Type) base. Each diffuser is 15 or 18 cm (6 or 7”) wide and is made in lengths ranging from 0.5 m (1.6 ft) to 4.5 m (14.8 ft). Custom lengths are available. The heaviest diffuser we make is 12 kg (27 lbs). Every diffuser – yes, every individual diffuser – is pressure tested and operated while submerged in our test facility, and then hand-stamped with a unique serial number. ASCE oxygen transfer testing is also available in our 230 m3 (60,000 gallon) test tank.

Installation:
AEROSTRIP diffusers are shipped to the site and installed according to the layout designed by Ovivo’s process engineers. Diffusers are typically mounted right on the floor, eliminating dead zones. Mounting bars may be used to mount multiple diffusers adjacent to each other to minimize penetrations into the concrete floor, to raise the diffusers, or for sloped floors. Stainless steel, HDPE tubing and PVC pipe is used for the air supply system. The strip shape allows for maximum flexibility in layouts as well as the possibility for high floor coverage.

What are the diffusers made of?
The base plate, peripheral strips and air connections are made from 316 stainless steel for the “T” type. The “Q” type is made from PVC. The membrane is made from a proprietary thermoplastic polyurethane material selected to provide longevity as well as superior properties for fine bubble formation and backflow prevention.
What is the range of the airflow capability of the AEROTSTRIP® diffuser?
In general, AEROSTRIP diffusers have an operational range from 5 Nm3/m2/hr (0.3 scfm/ft²) to 150  Nm3/m2/hr (9 scfm/ft²) with a turndown range from 12:1 to 24:1, unparalleled in the industry. Diffusers are also designed for regular or intermittent operation. Consult the plant O&M manual for specific limits of any individual system.
How are the diffusers mounted inside the tank? What are the mounting or floor tolerances?
Diffusers can be installed directly on the tank bottom or elevated if required. Grit removal (if necessary) is actually easier when the diffusers are installed very close to the bottom. Diffusers attach to the same air header and should be leveled within ±2.5 cm (±1“) of each other. The diffusers should be level to ±0.6 cm (0.25“) along its length to ensure peak performance.
Why is floor mounting important?
Floor mounting eliminates the effects of vibration and ragging that cause elevated diffuser systems (basically all other systems) to prematurely fail. Also, floor mounting eliminates grit accumulation zones, reducing maintenance requirements and maximizing available process volume. Mixing requirements are 20-40% lower with floor mounted systems, saving energy and allowing more flexibility in dissolved oxygen control when the DO setpoints need to be low. Studies have shown adequate mixing for floor mounted AEROSTRIP systems of 1.3 – 1.8 Nm2/hr/m2 floor area (0.07 – 0.10 scfm/ft2 floor area).
How do we connect the diffusers to the main air supply distribution?
In large plants, the air headers often run across the bottom of the tank feeding two rows of diffusers. Each diffuser is then connected to the air header by standard plastic tubing and fittings. Other possible configurations are available to meet your unique site constraints, including HDPE drops directly from the main header at the top of the tank.
Do we have to schedule the cleaning of the diffusers on a regular basis? How are they cleaned?
A large number of our AEROSTRIP installations have the diffusers running in an on-off mode (e.g. for denitrification) and do not require any cleaning. For plants that are running at a constant airflow, we recommend the use of a daily relaxing cycle, (i.e., turning the air flow off and releasing the air from the system for a few minutes per day and then restarting). This relaxing cycle squeezes deposits out of the pores before they have a chance to accumulate. For some industrial plants where chemical deposits build up even with the relax cycle, we have successfully dosed an organic acid feed into the air supply for a day or two, every other year, while the basin is online.
How long is the life expectancy for a membrane?
The membrane has a life expectancy of 15-20 years for municipal wastewater applications. We have installations with AEROSTRIP diffusers running for longer than 18 years without membrane replacement.
Why is this system more efficient than other systems? Is it prone to clogging?
Our diffusers produce very fine bubbles that rarely coalesce. The bubble release is very uniform across the surface. This is a result of superior membrane and perforation expertise that leads to increased efficiency. The strip shape adds to the efficiency when compared to other configurations. It is not prone to clogging as particles are squeezed out when the pores are closed, which occurs when the air is shut off. Our diffusers are preferred for on-off operation. The following video illustrates the advantages of the unique AEROSTRIP check valve needle perforation technique.
Have you performed any oxygen transfer efficiency tests with a third party independent institute?
Yes, many independent consultants have performed field testing on existing AEROSTRIP installations. In addition, we use clean water testing as a production quality control measure. For this purpose we have installed a test tank inside our production facility. Test reports are available upon request.
How high are the costs of your system, compared with other systems?
The AEROSTRIP diffusers are energy efficient for both low and high-density systems. We are cost competitive when life cycle costs are considered, even at relatively low power rates.
Can we use the AEROSTRIP diffusers to upgrade an existing plant? Does this limit the existing mixing capability of the plant?
The AEROSTRIP diffusers can be laid out in a very efficient manner and can be designed to avoid all existing obstacles. Existing piping for coarse bubble and tubular diffusers can be utilized for substantial savings, as the ¾” fittings can be used to connect the new strip diffusers. The smaller the bubble size, the better the mixing for a given air flow. Mixing typically requires 1.3 – 1.8 Nm2/hr/m2 floor area (0.07 – 0.10 scfm/ft2 floor area) with floor-mounted AERSOTRIP diffusers.
What is the safe-operating temperature range for the AEROSTRIP diffusers?
The maximum operating temperature of the wastewater is 35 °C (95 °F), which is acceptable for all US municipal applications (we have AEROSTRIP installations in FL, AZ, and CA). The water surrounding the diffuser must never be allowed to freeze. Temperature limits for storage are -5 °C to 40 °C (23°F to 104°F). If the diffusers are to be stored outside at or below freezing temperatures, frost damage must be avoided. UV inhibitors are added to the AEROSTRIP membranes. However, as with all thermoplastic materials, the membrane can be damaged from long-term exposure to UV light. The diffusers should be kept in their shipping crate until they are ready to be installed. Once installed, it is recommended to maintain 1 m (3.3 feet) of water over the diffusers during prolonged idle periods.
Can we use the AEROSTRIP diffusers at a water temperature higher than 35°C (95° F)?
We use our silicone membrane for higher water temperatures (theoretically up to 200°C = 392°F) and/or aggressive chemical environment. This membrane has the similar high efficiency as the polyurethane membrane. The life expectancy of such a membrane is estimated to be 7-10 years. We have installed plants with these silicone membranes, installation list available upon request.
How much does the pressure drop increase during 15 years of operation?
AEROSTRIP membranes use no fillers or plasticizers. Reduction of flexibility or other deterioration of membrane performance with time will be minimal. Using the relaxing cycle is typically sufficient to prevent significant clogging of pores over the life of the membrane. If required, the occasional dosing of organic acid in to the air supply line will clear deposits, ensuring that the pressure drop will not increase by more than 0.2 psi even after 15 years of operation.
How many installations to you have?
There are approximately 1,800 AEROSTRIP installations worldwide with over 75 installations in the USA.
Technical data of the membrane:
Thickness of membrane: 0.6 mm (0.024 inch)
Size of perforations: 0.2 mm  (0.0079 inch)
Number of perforations:  ~40/cm2 (~260/ inch2)

AEROSTRIP® fine pore diffusers have the highest proven energy-efficiency and the longest documented service life in the world. Advanced perforation technology and a high strength polyurethane membrane are the secrets to its high performance. Ovivo can guarantee clean water transfer efficiencies of 8.5-10%/m (2.6-3.0% ft) side water depth (SWD) in virtually all applications. Long term warranties are available.

AEROSTRIP® fine pore diffusers have the highest proven energy-efficiency and the longest documented service life in the world. Advanced perforation technology and a high strength polyurethane membrane are the secrets to its high performance. Ovivo can guarantee clean water transfer efficiencies of 8.5-10%/m (2.6-3.0% ft) side water depth (SWD) in virtually all applications. Long term warranties are available.

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Ovivo sells AEROSTRIP® high efficiency membrane type aerators under a distribution agreement. For further information about the availability of this product, please contact our Customer Contact Center. AEROSTRIP® is a registered trademark of Aquaconsult Anlagenbau GmbH. OVIVO is the exclusive agent of the AEROSTRIP® technology in the United States and its territories, Canada, India and South Africa. Contact us if your desired country is not listed.