Wastewater treatment
Upgrading and Retrofitting an Energy-Saving Aeration System at a Municipal Wastewater Treatment Plant
A municipal wastewater treatment plant (WWTP) with a daily treatment capacity of 50,000 cubic meters faced numerous challenges due to its traditional aeration system relying on outdated positive displacement blowers. This system accounted for nearly 60% of the plant’s total energy consumption, exhibited high noise levels (approximately 100 decibels), and required frequent maintenance due to its oil-lubricated components. To improve operational efficiency and meet increasingly stringent environmental regulations, the plant replaced its outdated blowers with an advanced A ”air-suspended centrifugal blower” system.
This air-suspended centrifugal blower utilizes ”air foil bearing technology” and is driven by a high-speed permanent magnet motor. Unlike traditional oil-lubricated spiral or Roots blowers, this system can form an air film with a thickness of micrometers, achieving frictionless, oil-free rotation at speeds exceeding 30,000 rpm. The system integrates a variable frequency drive (VFD) to precisely match aeration requirements based on real-time dissolved oxygen (DO) levels in the biological treatment tank.
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Result
By replacing four dual-blade blowers with two 100 hp and two 75 hp air-suspended blowers, the wastewater treatment plant achieved the following goals:
Energy Savings:
Unit energy consumption (kWh/m³) decreased from an average of 0.038 to 0.022, achieving energy savings of over 30%, with an annual energy saving of approximately 472,000 kWh.
Maintenance:
Oil-free operation eliminates lubrication costs and residue risks, is expected to reduce maintenance costs by 60%, and prevents contamination of the biological treatment process.
Noise Reduction:
Noise levels in the blower room decreased from 110 dB to below 80 dB, improving the working environment.
Conclusion:
The transition to air-suspended centrifugal blowers has yielded significant economic and environmental benefits. This project saves over $18,000 in electricity costs annually and reduces carbon dioxide emissions by approximately 163 tons. This case demonstrates that air-suspension technology provides a highly reliable and sustainable solution for aeration, helping water utilities achieve their decarbonization goals while ensuring compliance with emission standards.
