Urban Acoustic Profile of ALS2 Plant Operations
The hum of machinery in a city-fringe workshop rarely draws public attention until it crosses a threshold, and neighbours lodge complaints quick smart. For Ikoi S.p.A.'s ALS2 acidless separation line — the modular precious-metals recovery unit developed under the European Union's Horizon 2020 programme — that threshold sits well below it. Early acoustic surveys of pilot facilities in northern Italy showed readings well below those of comparable smelting operations, and those numbers are now being verified in urban demonstration plants that are shaping where e-waste processing can sensibly happen in Australian cities.
Australia's appetite for compact, containerised recycling technology is growing because the country processes roughly 200,000 tonnes of e-waste each year and most of it has historically been shipped offshore. Schemes such as the National Television and Computer Recycling Scheme, paired with drop-off points run by Mobile Muster and eCycle, are keeping more devices inside the country, but they need local refining capacity to keep precious-metal loops closed. Sound profile becomes a make-or-break siting factor when those facilities nestle into light-industrial pockets in places like Parramatta, Preston, or Osborne Park.
Acoustic baseline of the core process modules
The ALS2 platform replaces acid baths with a closed-loop electrochemical and mechanical sequence that recovers gold, silver, palladium, and platinum from printed circuit boards, connector pins, and WEEE fines. Acoustic instrumentation at pilot sites — typically Type 1 sound level meters deployed at the perimeter of each module under ISO 1996 procedures — records a stable signature across operating modes. The shredder and classification cyclone cluster between 78 and 84 dB(A) at one metre from the enclosure, while the hydrometallurgical agitation cells sit closer to 70 dB(A). The final electrowinning cells and drying cabinets often measure in the low 60s, producing a step-down pattern downstream.
What separates this profile from a conventional smelter is the absence of a sustained high-frequency roar from burners, kilns, or acid mist extraction stacks running at full chat. The dominant tones are broadband and mechanical, originating from rotor blades, pumps, and ventilation, which means standard enclosure and damping treatments can chip away at the loudest sources without redesigning the process. Continuous monitoring on the demonstration line has logged equivalent continuous A-weighted levels (LeqA) inside the plant between 72 and 80 dB(A), with peaks during feedstock loading rather than during the recovery cycle. By contrast, a small-scale torch-and-acid refinery in the same kind of shed would spike at 95 dB(A) and higher, largely because of thermal stress fractures in scrap and fume scrubber fans.
| Source within the ALS2 line | Typical LeqA at 1 m (dB) | Typical LeqA at property boundary (dB) | Notable tonal content |
|---|---|---|---|
| Size reduction and classification | 78–84 | 48–54 | Mid-frequency broadband |
| Electrochemical agitation cells | 68–72 | 42–46 | Low-frequency pump hum |
| Electrowinning and drying cabinet | 60–65 | 36–40 | Minimal tonal content |
| Full integrated train, idle mode | 58–62 | 32–36 | Ventilation-dominated |
| Reference: small torch-and-acid refinery | 92–98 | 60–68 | High-frequency burner roar |
Figures reflect consolidated panel output and reference measurements drawn from pilot monitoring and published WEEE-processing acoustics literature. Site-specific results will vary with building envelope, layout, and feedstock.
Comparing acid-based and acidless refining acoustics
Acid-based recovery depends on concentrated baths, fume hoods pulling corrosive mist through extraction stacks, and occasional torch cutting. The acoustic consequence is a layered canopy of broadband roar from extraction fans, the shriek of venturi scrubbers, and intermittent bursts of cutting noise that read like claps of thunder against the steady background. Sound maps drawn around legacy operations in inner Sydney and Brunswick show the property boundary reading regularly clears 60 dB(A), which is the kind of figure that brings a knock on the door from a local council officer.
Acidless separation trims that profile because the loudest energy stays contained inside engineered vessels and the dominant moving parts operate at modest rotational speeds. No industrial process is truly silent, but the ALS2 signature is far less intrusive than the alternative. European pilot data, validated against Australian field deployments done with university research teams in Wollongong, consistently returned boundary readings around 50–55 dB(A) when the train was housed in a standard corrugated shed with acoustic louvres. The shift in character matters as much as the shift in level: broadband mechanical hum is far less penetrating into nearby residences than the high-frequency whine of an extraction stack, and it is much easier to attenuate with off-the-shelf lagging without redesigning the shed.
Regulatory frameworks across Australian urban zones
Noise compliance in Australia runs through a layered system: state environment protection authorities set the principles, local councils enforce them, and the National Construction Code sets building envelope standards. The Protection of the Environment Operations Act in NSW, the Environment Protection Act in Victoria, and similar instruments in Queensland, Western Australia, and South Australia share a "no unreasonable noise" test. Daytime LAeq limits for industrial premises adjoining residential receivers typically sit between 55 and 65 dB(A), with tighter numbers where a shed backs onto a quiet suburban street in Haberfield, Indooroopilly, or Burnside, and looser figures inside designated industrial precincts near Flemington, Welshpool, or Carole Park.
Two standards do most of the heavy lifting. AS/NZS 1269 sets occupational noise management thresholds, capping unprotected exposure at 85 dB(A) over an eight-hour shift, with hearing protection compulsory at and above that level. AS/NZS 2107 covers acceptable indoor noise levels for various building types, useful when a facility sits inside a warehouse co-located with offices. Operators planning to drop an ALS2 train into a suburban light-industrial lot usually ask acoustic consultants to model LAeq at the most affected receiver before council sign-off, which is where the relatively quiet ALS2 profile pays dividends — the predicted boundary level typically lands well inside the day-time trigger without a cladded-on acoustic shed that would blow out the project budget.
Day-time scheduling and continuous monitoring do the rest. Most state regulators permit noisier activities between 7 am and 6 pm on weekdays than on weekends, which points to a 7-to-5 weekday pattern for the noisiest size-reduction module. Permanent boundary monitors logging LAeq, LA90, and LA10 to a cloud dashboard give the operator a paper trail that satisfies any future audit — fair dinkum, no drama when a complaint lands on the council's desk.
Mitigation strategies inside compact urban plants
Treating noise after the fact costs real money, so operators picking the ALS2 line tend to spec acoustic controls from day one. Common moves include flexible connectors on ducting between the size-reduction module and the cyclone, vibration isolators under the agitation cells, and acoustic louvres on the ventilation path instead of plain weatherproof cowls. Inside the shed, baffles in the ceiling void and mineral wool lagging on the cyclone housing typically shave 6 to 10 dB off the loudest sources without making the workspace stuffy for the tradies working the line.
Daytime scheduling helps too. Running the shredder during business hours rather than overnight means the worst broadband hum does not interfere with residents trying to sleep, which keeps the council phone quiet and the local paper free of angry letters. Real-time monitoring stations feeding dashboards on a tablet behind the office desk let the operator check the boundary reading during a noisy loading event, then update the compliance log on the fly. That approach is cheaper and faster than retrofitting a full acoustic enclosure, and Australian acoustic consultants have been quick to recommend it for sites in places like Geelong, Campbelltown, and Canning Vale where industrial land is wedged between housing estates.
Where space is tight, containerised ALS2 modules arrive pre-fitted with mass-loaded vinyl barriers and acoustic doors, so the commissioning engineer can plug the unit in and start processing boards within days rather than months. Drop-in attenuators on the inlet and outlet ducts push the worst broadband tones below the most common night-time LA50 trigger of around 40 dB(A), so at a typical residential receiver the plant reads closer to ambient than to industrial, even at the closest shed wall.
Community integration and social licence
Social licence matters as much as a compliance certificate in urban e-waste processing, and that means thinking about the soft stuff — the look of the shed, the smell, and yes, the sound — long before construction starts. Early conversations with local residents, especially in suburbs with active community associations like Newtown, West End, or North Perth, often settle complaints that would otherwise bubble up after the first loud shift. A neighbourhood open day with clear summaries of the monitoring report goes a long way toward building trust, especially when local schools and not-for-profits get a tour and see that the technology is more akin to a sterilisation unit than a smoky foundry next door.
ALS2's proponents lean on the fact that an acidless process produces no acidic mist, no toxic fumes, and a quieter operating envelope, which together lower the historical barriers to siting precious-metals recovery in populated catchments. That profile suits Australian council ambitions to keep circular-economy infrastructure local, particularly under state strategies that fund resource recovery precincts near major logistics corridors. Where the alternative is shipping circuit boards overseas in containers, the modest acoustic footprint of a containerised ALS2 train looks like a fair swap when balanced against the avoided emissions of long-haul export.
For operators weighing siting decisions in 2025 and beyond, the ALS2 platform should comfortably clear urban boundary noise triggers when basic acoustic hygiene is applied to the building shell and ventilation path. Early movers in Sydney, Melbourne, and Brisbane are already producing compliance reports that align with AS/NZS and state EPA benchmarks, and those reports will shape how quickly the next generation of e-waste plants can be tucked into the urban fringe without raising the roof with regulators or ratepayers. To dig into the acoustic modelling, monitoring data, and siting guides that apply to your Australian council area, get in touch with the ALS2 project team through the website's contact page.