Emerging Technologies: Turbo Blowers Offer Energy and Cost Savings

When APG-Neuros came out with their revolutionary air-bearing technology just a few years ago in 2005, it was received with hesitation and skepticism on the wastewater market. Today, APG-Neuros’ air-bearing turbo blowers are installed in 443 locations in North America and 120 units are currently on order. The product has optimized and made aeration more energy efficient in wastewater treatment plants where the majority of APG-Neuros’ blowers are installed, bringing a much-needed change to the aging technology on the blower market.

Since the Single Stage Centrifugal (Magnetic Driven) came out on the market in 1985, for almost 20 years there was little technological advancement in the blower industry – until the Single Stage Neuros Turbo Blower was introduced in 2003.

APG-Neuros’ Turbo Blower technology was founded in the aerospace and defense industry where Aero Engines were used in Unmanned Aerial Vehicles (UAV) and in the F-16 military aviation program, making the technology tested and reliable. The core of the technology is the patented 3rd generation bump foil air bearing which is oil-free and non-contact, needing no lubricating or associated maintenance resulting in lower vibration from the rotor during operation. It proved to have durability and endurance which was demonstrated through 25,000 starts; equivalent to more than twenty years lifetime in a typical operation.

Another key technology within the blower is the high-efficiency impeller, which is designed using in-house software based on aero gas turbine engine technology. It’s a solid forging impeller machine with 5-axis machining for higher integrity and higher fatigue life, as well as a larger diameter and precise impeller shape combined with optimal speed resulting in higher efficiency. The Permanent Magnet Synchronous Motor (PMSM) transfers EMF to load rather than windings and slip rings with no physical contact between stator and shaft, offering high precision motor speed control. Driven by sinusoidal PWM algorithm lowers motor heat rejection and minimizes cooling requirements resulting in energy savings.

Other design features include the cooling of the blower core, the VFD and the control systems with the blower inlet air. With no heat rejection to the blower room, no auxiliary exhaust systems are required and no additional power consumption for cooling. The 200 to 700 HP models have an Integrated Glycol cooling system for higher performance and durability with no external water supply required. Additionally, every standard turbo blower model comes with a Programmable Logic Controller which makes it possible to run the blower in constant pressure, flow or DO control mode, making controlling, monitoring and diagnostics easy. APG-Neuros’ blowers can attain flow rates of up to 20,000 SCFM and a discharge pressure up to 15 PSIG. The Dual Core models NX400 (400 HP) to NX700 (700 HP) combine two cores within the same enclosure unit to provide flow rates range between 3000 and 20,000 SCFM.

The Turbo Blower’s innovating design results in many benefits; primarily the energy and operating cost savings of up to 35%[1] when compared to the conventional Positive Displacement Blower. “Turbo blowers operate at high speeds, 20,000 rotations per minute (rpm) to more than 40,000 rpm, which results in efficiency improvements because dynamic efficiencies of compressors increase with increasing speed.”[2] Energy consumption being one of the biggest parts of operating costs of a WWTP; this could represent significant operational cost savings.

A study was conducted by CDM at the Franklin, NH WWTP where aeration accounted for approximately 36% of the total electrical consumption at the plant that used Positive Displacement blowers for the aeration process. The blowers were inefficient and required excessive maintenance2. The new APG-Neuros high-speed turbo blowers were installed in the plant for a period of nine weeks for a demonstration, “during which power draw, pressure, airflow, and DO concentration data were collected. The demonstration showed that a 32 to 35 percent reduction in direct wire-to-air power consumption could be achieved through upgrading the blowers.”2

Similar results were observed during a demonstration project at the Central Advanced WWTP in Fort Myers, FL. The Central AWWTP biosolids processing facility includes an aerobic digestion system that utilized one of three multistage centrifugal blowers installed back in 1994.  Power data was collected for each of the demo turbo and the multistage centrifugal blowers over a period of approximately 4 days. The demonstrated test showed average power savings of 37% compared to the multistage blower. 3

Savings could be improved further by automating the control system of the aeration process. In manually controlled systems, the controls typically are set to meet the maximum demand in a particular period of the day, and staff adjust the equipment either daily or weekly. However, load fluctuations cause oxygen demands to change constantly. Besides wasting energy, the excess aeration may hamper treatment by shearing flocculated particles too much.[3]

These additional energy savings and operational flexibility could be achieved thanks to the turbo blower’s variable frequency drive (VFD) that the blower comes with, which makes it possible to adjust the speed of the blower, and the blower’s turndown flow rate of up to 76%. This operational flexibility allows the control of the blowers to be automated, which “typically use DO probes and analyzers to measure DO in aeration systems and adjust airflow accordingly in real time”3 maximizing energy efficiency.

Up to 12 APG-Neuros blower can be controlled by a Master Control Panel (MCP) simultaneously, operating based on input command of DO, Pressure or Flow Control. The MCP gives the plant SCADA system one point of contact for all blower data, aeration control set points and control process data. Likewise, it manages start/stops and speeds for all of the blowers.

Unlike the conventional blowers, the Turbo blower has also low noise and vibration thanks to the no-contact air bearing and APG-Neuros’ patented Noise Trapping System enclosure design which effectively controls sound propagation and reduces noise levels to 70-85 dB(A). The low vibration eliminates the need for heavy foundations for the blower to be installed on, thereby significantly reducing the installation costs. These are further reduced thanks to the smaller footprint of the turbo blower; up to 55% smaller compared to technologies with similar flow rates.

Furthermore, operating costs are significantly smaller thanks to the low maintenance of the turbo blower because it required no oil, liquid or belts to change. The maintenance is limited to the periodical need of cleaning or changing the air filter and checking the glycol fluid levels for the models of 200HP to 700HP.

Finally, APG-Neuros has an extensive customer and technical support network in proximity to its customers, with in-house field service engineers in the West and East coast of the United States, and over 35 APG-Neuros factory-trained and certified technicians all around the country providing its customers with a quick response time.

APG-Neuros’ product is welcomed and accepted as the future of blowers in the wastewater market. The blowers allow WWTPs to be more environmentally sustainable, energy efficient and cost-effective which are all growing concerns for WWTPs. “APG-Neuros’ Turbo Blowers are the greatest thing that have come along in a long time. It’s a great and easy to use blower that runs flawlessly and requires minimal maintenance” noted Jonathan Lane a Wastewater Operator from Benicia, CA.

Elana Podvalniuk – March, 2012

[1] Based on a third-party case study published in WE&T. Katherine Bell, Jason Sciandra, and Kevin Wagner, “Aerate for Less; Turbo blowers can cut energy costs by more than 35%”, WE&T (2010)

[2] Bell, Katherine, and S. Abell. “Optimization of WWTP Aeration Process Upgrades for Energy Efficiency.” International Water Association Publishing 6.2 (2011). Print

[3] Katherine Bell, Jason Sciandra, and Kevin Wagner, “Aerate for Less; Turbo blowers can cut energy costs by more than 35%”, WE&T (2010)