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New mounting system allows for easier and safer aeration system maintenance

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Aire-O2™ Universal Mount
The Universal Mount allows for aerator maintenance to be performed without the need for operators to enter the basin or reach over railing.

By Erin (Kober) Biesanz, Jing Huang and Josh Sablan

Through conversations with plant operators and service experience, Aeration Industries recognized the importance of maintenance and safety for those servicing wastewater aeration equipment. The idea to develop a mount on a sliding pedestal so operators could maintain equipment safely on the walkway was conceived.

The secondary goal was to reduce the cost of maintenance and give plant operators the ability to service equipment on their own versus having to hire service teams. Plant operators are also facing strict permit limits, allowing less downtime for maintenance and repairs, so this needs to be done efficiently without having to shut down the whole plant.

Conventionally installed aeration equip­ment often requires difficult and time-consuming maintenance. Surface mounted equipment relieves a portion of these issues, as all working components are readily available for full service without shutting down operations. Float mounted surface aerators pose unique maintenance challenges, including: servicing from within the basin, the requirement of cranes, and the need to move equipment to the shoreline or basin perimeter.

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To address these unique concerns, Aeration Industries International developed the Aire-O2™ Universal Mount. With the use of a patented slide design and a low cost “mini-crane”, aerators are hoisted and pivoted into a position that allows for simple service. The sliding mechanism allows the unit to move through varying water depths, creating a design that combines operational flexibility with ease of maintenance.

Universal-Mount-diagram
The sliding pedestal travels on a 45-degree track that allows the aerator to be positioned at the desired height. A pivoting tube allows the aerator to point in any direction.

The Universal Mount is an all stainless steel mounting structure that is partially submerged and installed on the walls or walkways of wastewater treatment basins. The structure has a sliding pedestal on rollers with a solid bearing. The solid bearing has no moving parts, so it is durable in harsh wastewater environments, especially in a submerged condition. The sliding pedestal travels on a 45-degree track that allows the aerator to be positioned at the desired height depending on the freeboard. On the sliding pedestal, there is a pivoting tube that allows the aerator to point in any direction to form a flow that will keep solids suspended efficiently.

Pedestals are pulled up and down by a cable which runs on a pulley that sits on top of the track. The pulley is engaged by a hand winch that is integrated into the mounting system. The hand winch and its pedestal are designed to be portable. Multiple universal mounts can share one hand winch for bringing the unit up and down. Universal Mount only requires four anchor bolts on top and two anchor bolts on the front to complete the installation of the mounting system.

When maintenance is due, operators can access the unit without a boat or renting a crane, allowing for safe and efficient maintenance. The whole process of bringing the aerator into the maintenance position takes no more than 10 minutes.

The Universal Mount in practice

One wastewater treatment plant sel­ected Aeration Industries’ Aire-O2 Triton® aerator/mixers coupled with Universal Mounts to replace aging rotors. Prior to the replacement, the plant had an oxidation ditch with six rotors. The rotors were not fully aerating the tank due to welds and bolted sections of the baffles failing and falling into the bottom of the ditch. With a 4.5 m deep ditch, it was very important that treatment was occurring throughout the entire volume of the ditch.

Access to the rotors was also very challenging for cleaning rags and other debris off the shaft and blades. To pull the rotors out, the operator had to pull the motor, gearbox and the seal plates at each end. There were also several problems with motor and gearbox failures. It was often a full day of work to maintain or fix one rotor.

Operators were looking for a new type of aerator with easy access for maintenance and repairs. Two Aire-O2 Triton aerators with the Universal Mount were installed to determine if the mounting systems were appropriate. Installation went smoothly. The mounting holes for the mount were pre-drilled before installation day and it only took half a day for the two mounts to be installed on the existing concrete walkway where the rotors were originally installed. Also, the mounting installation did not require the removal of existing rotors.

The mounting system allowed all wiring to be done right on the walkway. When it came time for maintenance, an operator only needed to crank the unit up with the hand winch. It took them one to two hours to do the maintenance on the walkway for each unit. This was much less time than with the previous rotors.

After running the Tritons on the mounts for approximately eight months and seeing the performance of the aerators, along with testing the ease of maintenance of the mounting system, eight more aerators were installed.

A month after startup with all 10 aerators running, the plant saw such successful mixing that they had to waste significantly more sludge than with their previous systems. They are also seeing better treatment, specifically lower total nitrogen numbers, which is due to the entire volume of the basin being aerated.

Safety

One of the primary concerns with the improved mounting system was increasing safety when maintenance is required on aeration system equipment. The Universal Mount addresses this need, as operators never need to be in the water to service the equipment. Everything can be done safely on the walkway and reaching over the water has been eliminated.

The mount also diminishes the need for operators to drain the basin or climb down onto the equipment to make repairs. This reduces risk of injury while also simplifying the maintenance process.

Health was an essential concern, as well. There is a risk of Legionnaires’ disease if wastewater splashes and creates a mist that is inhaled by operators. The Aire-O2 Triton does not create any splashing or mists and the mounting system does not require operators to be over the water, nearly eliminating this health risk.

Erin (Kober) Biesanz, Jing Huang, and Josh Sablan are with Aeration Industries International. This article appears in ES&E Magazine’s February 2018 issue.

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