Applications of Blowers in Urban and Rural Wastewater Treatment and Upgrading: Technological Evolution, Market Dynamics, and Opportunities under the Dual Carbon Goals

At the bottom of the aeration tank in every wastewater treatment plant, Blower With impeller clearances measured in fractions of a millimeter and energy‑efficiency standards that are almost stringent, the delicate balance of aerobic microbial activity is maintained. As the “dual carbon” goals elevate energy‑consumption metrics to a central pillar of wastewater‑treatment plant performance evaluation, blowers—long relegated to the status of ancillary equipment—are quietly emerging as pivotal factors that determine both the economic viability and the carbon footprint of upgrade projects.

I. The Core Role of Blowers in Wastewater Treatment Processes

The blower is the “heart” of the aeration system in a wastewater treatment plant, with the core function of continuously supplying dissolved oxygen to the aerobic biological treatment unit, sustaining the metabolic activity of aerobic microorganisms, and thereby achieving efficient degradation of organic pollutants (COD/BOD) and ammonia nitrogen.

From an energy perspective, the cost of this function is extremely substantial. In a typical municipal wastewater treatment plant, Aeration system energy consumption accounts for 50% to 70% of the plant’s total energy use. Meanwhile, as the power source of aeration systems, the energy consumption of blowers directly determines the energy‑cost structure of wastewater treatment. According to statistics from the China Urban Water Supply and Drainage Association, in 2023, urban wastewater treatment plants nationwide consumed over 18 billion kWh of electricity annually, with blower energy use accounting for approximately 40% to 55% of the total. This means that for every one‑percentage‑point improvement in blower efficiency, annual electricity savings could exceed hundreds of millions of kWh.

At the process level, different treatment technologies impose distinct requirements on the air-supply characteristics of blowers:

• A²/O and its improved processes (Mainstream accounting for approximately 60%): The blower is required to have a wide-range flow‑rate regulation capability to accommodate fluctuations in oxygen demand across different seasons and varying load conditions.
• SBR/CAST Sequencing Batch Reactor Process Aeration is characterized by intermittency, requiring the blower to start and stop frequently or undergo rapid load changes, which places stringent demands on equipment reliability and the response speed of the control system.
• MBR membrane bioreactor In addition to aeration for oxygen supply, a continuous air flow is also required for membrane cleaning, resulting in higher air‑pressure requirements than in conventional processes.
• MBBR fluidized bed process : Fluidization of the carrier requires a higher aeration intensity, resulting in a significant increase in the air supply rate per unit reactor volume for the blower.

Thus, it is evident that a blower is not merely an independent piece of equipment but rather a system‑level component deeply integrated with the treatment process. The appropriateness of its selection directly impacts both the compliance rate of effluent quality and operational costs.

II. Evolution of Blower Technology Roadmaps and the Competitive Landscape

2.1 Technological Generations: From Roots Blowers to Air-Suspension Technology

The blowers used in the wastewater treatment industry have undergone a clear technological generational evolution, with each new generation driven primarily by improvements in efficiency and simplification of maintenance.

This evolutionary trajectory reveals an essential trend: Technological advances in blowers have consistently focused on reducing losses in the energy conversion process. Roots blowers rely on mechanical compression, which inherently suffers from volumetric clearance leakage and incomplete internal compression losses; multistage centrifugal compressors incur interstage losses and gear‑drive inefficiencies that account for a significant portion of their energy losses. In contrast, magnetic‑levitation and air‑bearing technologies eliminate mechanical bearing friction and gear‑drive losses, pushing energy‑transfer efficiency to new heights.

2.2 Current Market Landscape

From a market‑share perspective, China’s wastewater‑treatment blower market is undergoing a structural shift:

• Roots blower Its share in newly built large and medium-sized projects continues to decline, but it still maintains a certain presence in small-scale wastewater treatment plants and integrated township‑level systems; its cost‑effectiveness enables it to remain competitive in budget‑sensitive projects.
• Single-stage high-speed centrifugal blower (Represented by foreign brands such as Howden, Siemens, and Gardner Denver, as well as domestic manufacturers like Jintongling and Shenyang Blower) continue to hold a significant market share in medium- and large-scale wastewater treatment plants, particularly in projects with capacities exceeding 100,000 m³/day.
• Magnetic Levitation/Air-Levitation Blower It is the fastest-growing subcategory. Taking magnetic levitation as an example, domestic manufacturers (such as Yisheng Technology, Reitz Intelligent, and Nanjing Cigu) are competing with international brands (including ABS and Neuros) for market share. The compound annual growth rate from 2020 to 2024 exceeded 25%. Its penetration rate has been rapidly increasing in new and retrofit projects for wastewater treatment plants with capacities ranging from 30,000 to 200,000 m³/day.

Notably, domestically produced magnetic‑levitation blowers have achieved breakthroughs in key technologies such as core control algorithms and rotor dynamics design, with overall equipment costs reduced by 30% to 50% compared to imported products. This has significantly accelerated their adoption and deployment in wastewater treatment plants at the county level and in small and medium-sized cities.

III. Market Analysis of Blower Applications in the Context of Upgrading and Retrofitting Standards

3.1 Policy-Driven: The Inevitable Demand for Upgrading and Retrofitting Standards

Since the start of the 14th Five-Year Plan, policy direction in the wastewater treatment sector has shifted from “scale expansion” to “quality improvement and efficiency enhancement.” The combined effect of multiple policies has created a powerful impetus for the replacement and upgrading of blowers:

• Emission standards are being tightened. : Many regions have already implemented or plan to implement effluent standards equivalent to Class IV (Surface Water Environmental Quality Standards), with significantly stricter requirements for total nitrogen (TN) and ammonia‑nitrogen (NH₃‑N). This directly necessitates more precise dissolved‑oxygen control in aeration systems, thereby driving demand for advanced, finely tuned blower‑control capabilities.
• Energy Conservation and Carbon Reduction Assessment The National Development and Reform Commission and other ministries have incorporated the unit energy consumption of wastewater treatment plants into the green and low-carbon performance evaluation system. Meanwhile, many localities have issued energy-efficiency benchmarking guidelines for wastewater treatment plants, setting maximum limits on electricity consumption per ton of water treated.
• Equipment Upgrade Policy In 2024, the State Council’s “Action Plan for Promoting Large-Scale Equipment Upgrading and Consumer Goods Trade-In” designated the replacement of aging wastewater treatment equipment as a key priority, with low-efficiency blowers that have been in service for 10 to 15 years identified as prime candidates for replacement.

3.2 Quantitative Assessment of Market Size

Based on industry data and project tracking, a reasonable estimate of the market potential for blowers in the scope of upgrading and retrofitting to meet stricter standards can be derived:

• As of 2024, more than 5,000 urban wastewater treatment plants have been built nationwide, with a combined designed treatment capacity of approximately 220 million m³/day. Among them, Approximately 35% of the processing capacity has been in service for more than 10 years. That is, a treatment capacity of approximately 77 million m³/day involves aging blower equipment or substandard energy efficiency.
• Based on an average aeration power consumption of 0.8 to 1.2 kWh/m³, a treatment capacity of 10,000 m³/day would require an installed blower capacity of approximately 150 to 250 kW. Accordingly, the market for upgrading and retrofitting to meet stricter standards is estimated to generate replacement demand for blowers in the range of... Installed capacity of 1.1 to 1.9 million kW ；
• Based on the current market price of magnetic‑levitation or air‑bearing blowers—approximately RMB 2,500 to 4,000 per kW—if 50% of these units were replaced with high‑efficiency levitation blowers, the corresponding market size would be roughly RMB 15 to 30 billion (excluding piping, control systems, and installation costs).

This estimate is conservative: it covers only urban centralized wastewater treatment facilities and does not yet account for the blower demand associated with decentralized treatment systems in towns and townships, industrial park wastewater treatment plants, or extended applications such as aerobic sludge fermentation.

3.3 The Competitive Dimension: From “Equipment” to “Systems”

In upgrade and retrofit projects, the procurement logic for blowers is undergoing a profound shift. In the past, owners typically treated blowers as standardized, off-the-shelf equipment, basing their purchasing decisions on comparisons of three key parameters: airflow rate, static pressure, and power rating. However, in the context of upgrading and retrofitting to higher standards, the importance of the following factors has increased significantly:

• Compatibility with existing aeration piping and aerators In retrofit projects, pipeline conditions often cannot be significantly modified; therefore, the blower’s pressure–flow characteristics must be precisely matched to the existing system’s pipeline resistance curve.
• Part-load operating efficiency : After upgrading to meet higher standards, wastewater treatment plants typically experience more pronounced fluctuations in both influent flow and quality. Consequently, the efficiency of blowers operating within the 60%–80% load range is more practically relevant than their full-load efficiency.
• Intelligent Control Integration Capability : An aeration precision control system based on multiple parameters such as dissolved oxygen (DO), ammonia nitrogen, and mixed liquor suspended solids (MLSS)—such as a precise aeration/AVS system—requires blowers to feature millisecond-level response and stepless speed regulation.
• The convenience of renovation work The integrated skid-mounted design and low-vibration, low-noise characteristics of air‑suspension and magnetic‑levitation blowers enable replacement installations to be carried out without shutting down production, offering significant engineering advantages in upgrade and retrofit projects.

IV. Quantitative Analysis of Energy-Saving and Environmental Protection Benefits

The energy‑saving benefits of blower technology in wastewater treatment are not an abstract “green narrative”; they are quantifiable economic and environmental metrics.

4.1 Energy Consumption Comparison of Typical Retrofit Cases

Taking a municipal wastewater treatment plant with a design capacity of 50,000 m³/d as an example, suppose its original configuration consisted of three 75 kW Roots blowers (two in service and one on standby). During the upgrade to meet stricter effluent standards, these were replaced by two 110 kW magnetic‑levitation centrifugal blowers (one in service and one on standby), with the actual operating power dynamically adjusted according to the load.

The data above indicate that, under reasonable operating conditions, magnetic‑levitation blowers can achieve energy savings of 35% to 45% compared with conventional roots blowers, with a typical payback period of no more than 2 to 3 years. When combined with the optimization benefits of a precise aeration control system—further reducing aeration volume by 15% to 20%—the overall energy‑saving potential can exceed 50%.

4.2 From the Perspective of the Full Lifecycle Carbon Footprint

From the perspective of the “dual carbon” goals, assessing the environmental benefits of blowers requires going beyond a mere analysis of operational electricity consumption and adopting a full‑life‑cycle carbon footprint assessment:

• Carbon emissions during the operational phase This is the dominant component of a blower’s carbon footprint, typically accounting for more than 85% of its full lifecycle emissions. Adopting high-efficiency blowers to reduce operational electricity consumption represents the most direct and effective pathway for carbon reduction.
• Embodied carbon in the manufacturing phase : Magnetic‑levitation blowers employ permanent‑magnet synchronous motors and precision impellers, reducing material consumption per unit of power by 20%–30% compared with Roots blowers and resulting in a lower carbon footprint during manufacturing.
• Hidden Carbon Benefits During the Maintenance Phase Roots blowers require regular replacement of consumable components such as lubricating oil, belts, and bearings, resulting in significant annual maintenance-related carbon emissions that cannot be overlooked. In contrast, magnetic‑levitation blowers operate without contact, minimizing maintenance needs and thereby reducing the carbon footprint associated with the production and transportation of spare parts.
• Indirect Impacts of N₂O Emissions When aeration control lacks sufficient precision, N₂O—whose global warming potential is 273 times that of CO₂—may be produced in alternating aerobic–anoxic zones. The alignment between blower‑control accuracy and dissolved‑oxygen regulation makes a substantial contribution to reducing N₂O emissions during wastewater treatment—a factor that is often overlooked in conventional energy‑consumption comparisons.

V. Prospects under the “Dual Carbon” Framework

5.1 Carbon Trading and the Potential Value of Carbon Assets

China’s national carbon market was launched in 2021. Although the wastewater treatment sector has not yet been included in the mandatory compliance regime, the trend is already clear. The Ministry of Ecology and Environment has signaled, through multiple policy documents, its intention to integrate wastewater treatment into the carbon‑market system. Against this backdrop, energy‑saving measures for blowers will yield a dual benefit: reduced electricity costs and revenue from carbon‑asset trading.

Based on the 2024 national carbon market CEA average price of approximately RMB 80–100 per tonne of CO₂, the annual reduction of 255.5 tonnes of CO₂ in the aforementioned case corresponds to a carbon‑asset value of roughly RMB 20,000–26,000 per year. Although the absolute amount remains modest, as the carbon‑price floor continues to rise and CCER methodologies are refined, the value of this revenue stream will gradually expand. More importantly, Wastewater treatment plants with leading energy efficiency will enjoy a structural advantage in future carbon‑quota allocations. — High energy efficiency translates into lower compliance costs and a more substantial surplus of allowances.

5.2 Trends in Technological Convergence

The evolution of blower technology has not progressed in isolation; rather, it has become deeply integrated with the broader trends of digitalization and intelligentization:

• Digital Twins and Predictive Maintenance : By deploying a sensor network at critical locations such as the blower rotor, bearings, and windings, and integrating edge computing with cloud‑based models, real-time assessment of equipment health and early fault warning can be achieved. For magnetic‑levitation blowers, the rotor displacement sensors themselves provide a wealth of operational data, laying the foundation for predictive maintenance.
• AI-Driven Aeration Optimization Integrating blower control into a machine-learning–based aeration system enables the system to proactively adjust aeration strategies based on an influent load prediction model—incorporating historical data, weather forecasts, and network inflow characteristics—thereby minimizing blower energy consumption while ensuring effluent water quality.
• Photovoltaic–Blower DC Coupling : There is an inherent match between the distributed photovoltaic systems installed on the roofs and open spaces of wastewater treatment plants and the load of the blowers—during the day, the peak output of the PV system closely coincides with the peak aeration demand. By leveraging a DC microgrid or energy storage as a buffer, the blowers can directly absorb the PV-generated power, thereby reducing reliance on the grid and lowering the carbon emission factor.

5.3 Incremental Growth Potential in the Lower-Tier Markets

The integrated advancement of urban–rural wastewater treatment represents a significant and often overlooked source of growth for the blower market. As of 2024, the national wastewater treatment rate in established towns stands at approximately 65%, while that at the township level remains below 40%, highlighting a substantial gap compared with the over 98% rate observed in urban areas. Wastewater treatment facilities at the county and township levels are characterized by small scale (500–10,000 m³/day), dispersed locations, and limited operational and maintenance capabilities—conditions that impose product requirements on blowers markedly different from those of large urban wastewater treatment plants:

• Maintenance-free or low-maintenance Township facilities lack specialized technical personnel, and the “zero-contact, oil-free, lubrication-free” characteristics of magnetic‑levitation and air‑bearing blowers make them a natural fit for this application.
• Modularization and Skid-Mounted Design The blower and aeration control system are integrated into a standard skid-mounted unit, enabling “plug-and-play” operation and lowering the installation and commissioning threshold.
• Remote Monitoring and Operations & Maintenance : Equipped with a built-in IoT communication module, it supports remote start/stop, parameter adjustment, and fault diagnosis, enabling the county-level operations and maintenance center to centrally manage the operating status of blowers at multiple township sites.

Although individual projects in this lower-tier market are relatively small in scale, the sheer number of sites—exceeding 15,000 township‑level wastewater treatment facilities nationwide—results in a substantial cumulative market size. Moreover, this segment places higher demands on blower suppliers’ integrated “product + service” capabilities.

VI. Challenges and Rational Reflection

While acknowledging the substantial benefits brought by technological upgrades in blowers, it is equally important to maintain a rational perspective on certain trends currently observed in the industry:

First, the choice of technological approach should not be one-size-fits-all. Magnetic‑levitation and air‑bearing blowers offer distinct advantages under medium‑to‑small flow rates and moderate pressure ratios; however, for high flow rates (>300 m³/min), high pressure ratios (>1.5 bar), or specific process conditions, single‑stage high‑speed centrifugal blowers remain competitively indispensable. In some projects, a tendency to prioritize levitation over system performance—ignoring the fundamental principle of proper operating‑condition matching—can result in actual operational efficiency falling short of expectations.

Second, the effectiveness of the transformation is highly dependent on system compatibility. Replacing an efficient blower is only one link in the energy‑saving chain. If the diffusers are aged and clogged, causing an abnormal increase in pipeline resistance, or if a precise aeration control system is lacking and the plant continues to operate with a crude, constant‑air‑flow mode, even the most efficient blower will struggle to realize its full energy‑saving potential. The retrofit of blowers should be planned and implemented within the framework of “overall optimization of the aeration system.” 。

Third, the reliability of domestically produced suspended blowers still requires time to be fully validated. The core components of magnetic‑levitation blowers—the magnetic bearing controller and the high‑speed permanent‑magnet motor—still lack robust reliability data under long‑term (five years or more) continuous‑operation conditions. Some early‑deployed domestically produced units have experienced controller failures and inadequate rotor‑drop protection. As the industry expands rapidly, it must establish a more comprehensive quality‑traceability system and a long‑term reliability database.

VII. Conclusion

The application of blowers in urban and rural wastewater treatment, as well as in upgrading and retrofitting to meet higher standards, is currently undergoing a transformative phase shaped by the combined forces of policy-driven impetus, technological advancement, and market dynamics. The evolution from Roots‑type blowers to magnetic‑levitation models epitomizes the wastewater treatment sector’s shift from “rough compliance” to “precision and low‑carbon” operations. As every kilowatt-hour of energy saved carries the weight of carbon reduction, and as each blower selection is evaluated within the framework of life‑cycle cost analysis, blowers have ceased to be mere rotating machinery; they have become pivotal technological anchors for the green transformation of wastewater‑treatment infrastructure in the era of “dual carbon” goals.

For industry participants, understanding the value proposition of blowers can no longer be confined to comparing equipment specifications; it must now be elevated to… A systems-thinking approach integrating process, equipment, control, and carbon accounting. This is both a challenge and the true opportunity at the heart of this profound industry transformation.

This paper is based on publicly available industry data and technical literature, with the aim of providing a reference for professionals in the wastewater treatment sector. The estimated figures presented herein are derived from industry statistics and empirical data from typical projects; however, actual project decisions should be informed by a detailed techno‑economic analysis tailored to the specific operating conditions.