In both water and wastewater treatment, ensuring air quality is crucial. Compressed air plays a central role across multiple processes — but not all compressors are suited for these sensitive environments.
This article answers key questions stakeholders have about oil-free compressors in the treatment industry, covering necessity, compliance, operational performance, and common misconceptions.
Is Oil-Free Compressed Air Necessary in Water and Wastewater Treatment?
Air purity is vital in water and wastewater treatment operations. Compressed air is often used in aeration systems, ozone generation, instrumentation, and membrane filtration — all processes where contamination risks must be minimised.
Oil contamination from a compressor can lead to serious consequences: compromised water quality, fouling of sensitive equipment, and breaches of environmental and safety regulations. Even minor contamination events can result in costly remediation, fines, and reputational damage.
With treatment plants expected to operate reliably 24/7, oil-free compressors provide a safeguard, eliminating one of the major contamination risks while supporting consistent, safe system performance.
Oil-Free vs Oil-Lubricated Compressors: What’s the Difference?
Oil-lubricated compressors use oil within the compression chamber to cool and seal internal components. These compressors rely on filters to reduce oil content downstream. However, they cannot completely eliminate the risk of oil carryover. Over time, filters degrade or fail, increasing the contamination risk.
Oil-free compressors, by contrast, are engineered so that no oil is present in the compression process itself. Technologies like water-lubricated compressors offer cooling and sealing benefits without the risks associated with oil.
For water and wastewater treatment facilities, this distinction is critical. True oil-free systems reduce the chance of contamination, protect sensitive equipment, and minimise maintenance interruptions.
Although the initial cost of an oil-free compressor can be higher than an oil-lubricated model, the total cost of ownership is often lower. Savings are realised through reduced maintenance costs, elimination of oil filter replacements, lower downtime, and protection from compliance risks.
Meeting Compliance Standards with Oil-Free Compressors
Compressed air used in processes that come into contact with drinking water or influence water quality must meet strict standards.
ISO 8573-1 Class 0 certification is the benchmark for air purity, guaranteeing no detectable oil content. Facilities that use Class 0 oil-free compressors can confidently meet the strictest air quality requirements.
In Australia, equipment must follow AS/NZS 4020:2018 and be approved by the Department of Health WA. Oil-free compressors help facilities meet these requirements by eliminating the risk of introducing hydrocarbons into water systems, supporting compliance with the Australian Drinking Water Guidelines.
Oil-free systems also simplify compliance with environmental licensing obligations under the Environmental Protection Act 1986 (WA). By removing the risk of hydrocarbon contamination, they help treatment facilities satisfy licensing conditions, ease site audits, and demonstrate proactive environmental risk management.
Common Misconceptions About Oil-Free Compressors
Historically, oil-free compressors were seen as expensive, less durable, and difficult to maintain. However, recent advancements have changed the landscape significantly.
Modern systems like ELGi’s AB Series use water as the lubricating medium, delivering superior cooling without any oil contamination risk. The AB Series features fewer moving parts, slower rotational speeds, and specialised air-end coatings — all of which extend lifespan and reliability.
Additionally, the ELGi AB Series comes with a standard five-year warranty, providing assurance for Operations Managers and Procurement Teams looking to control CapEx and long-term maintenance costs.
In short, oil-free technology today offers reliability, energy efficiency, and value — without the compromises of the past.
Where Oil-Free Compressed Air is Used in Water and Wastewater Treatment
Oil-free compressors are used across critical treatment processes, including:
- Aeration systems — supporting biological treatment and maintaining oxygen levels
- Ozone generation — ensuring uncontaminated ozone production for water disinfection
- Instrument air — powering control valves, actuators, and SCADA systems without contamination risk
- Membrane filtration systems — supporting MBR, RO, and UF systems where air purity directly impacts membrane longevity and performance
In each case, oil-free compressed air ensures operational efficiency, protects critical infrastructure, and supports compliance.
Oil-free compressed air is no longer a niche option — it is rapidly becoming the industry standard for water and wastewater treatment facilities. By eliminating contamination risks, simplifying compliance, and offering long-term reliability and cost savings, oil-free compressors represent a smart investment in the future of your operation.
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