Quick answer: Commissioning a nutrient removal plant to its design basis is engineering — the outcome is determinable in advance. A core R&D activity may exist in the narrower case where no established basis predicts whether an intensification will hold nitrogen and phosphorus limits on a particular influent through cold weather or load swings, and the answer comes only from a systematic progression of work conducted to generate new knowledge. Routine licence monitoring is separately excluded from being core. The company must assess each activity against the statutory tests and self-assess its own claim.
24 August 2026 — this article describes the current rules. The 2026–27 Federal Budget announced R&DTI reforms that will apply to income years starting on or after 1 July 2028. Until then, the program continues to be administered under the current legislation, as stated by industry.gov.au .
Biological nutrient removal is not new science, and that is what makes the eligibility line here interesting: the settled part of the field stops well short of the question an operator is actually asking. The question is almost never "does nitrification work". It is "will this mixed liquor, on this influent, hold ammonia below the licence limit at 12 °C during the six hours a food processor discharges its day's load". The literature answers the first outright. It narrows the second — sometimes a long way — without settling it, and how far it narrows it is precisely what the eligibility test turns on.
The Statutory Test, Stated Once
Under s 355-25(1) of the Income Tax Assessment Act 1997, core R&D activities are experimental activities whose outcome cannot be known or determined in advance on the basis of current knowledge, information or experience, but can only be determined by applying a systematic progression of work that is based on principles of established science and that proceeds from hypothesis to experiment, observation and evaluation, and leads to logical conclusions; and that are conducted for the purpose of generating new knowledge, including new knowledge in the form of new or improved materials, products, devices, processes or services (business.gov.au; ITAA 1997). Section 355-25(2) then lists activities that are not core R&D activities; paragraph (f) — activities associated with complying with statutory requirements or standards, including routine testing and analysis of materials, components, products, processes, soils, atmospheres and other things — may be relevant to a licensed treatment plant.
A supporting R&D activity must be directly related to core R&D activities (s 355-30(1)). Where the activity is of a kind listed in s 355-25(2), or produces goods or services, or is directly related to producing goods or services, s 355-30(2) adds a further bar: it is a supporting R&D activity only if undertaken for the dominant purpose of supporting core R&D activities (business.gov.au). That third limb is the one that catches this sector, because a treatment plant produces a service continuously and never stops while the trial runs.
The established-science limb is rarely the obstacle in wastewater: microbial kinetics, oxygen transfer theory and reaction stoichiometry supply a settled body of principle, though whether it is satisfied still turns on how the progression is designed, conducted and evaluated. The limb that bites is the first. Novelty to the company, difficulty and cost are not the test.
Why the Microbial Response to a Particular Influent Is Not in the Literature
Three mechanisms account for most of the genuine uncertainty in intensifying an existing plant:
Nitrifier kinetics fall with temperature, and rate — not inventory — is usually what fails: Ammonia-oxidising bacteria are slow-growing autotrophs with a strong temperature dependence. On the temperature coefficient conventionally used in design practice, about 1.07 per degree, a drop from 20 °C to 12.5 °C cuts the maximum oxidation rate to roughly 60% of its value. In an extended-aeration plant running a solids retention time of two to three weeks, that rarely causes nitrifier washout — the inventory is enormous. What it erodes is the instantaneous rate margin, so the plant fails at the peak rather than on the average. Nitrification also consumes alkalinity, stoichiometrically close to 7.1 mg as CaCO₃ per mg of nitrogen oxidised, while denitrification returns about half of that, so a low-alkalinity or acidic trade waste can pull pH into a range where the rate falls again. A calculation narrows the expected margin; whether the residual margin survives a particular load shape on a particular mixed liquor is usually settled only by measuring it.
Oxygen transfer, not biology, often sets the ceiling: The alpha factor relating field to clean-water transfer efficiency in fine-bubble diffused systems falls as mixed liquor solids rise, and varies with the surfactants and colloidal organics in the influent. That is the mechanism behind one of the most common failed intensifications: adding biomass to add capacity, and losing more in transfer efficiency than is gained in inventory. It is also why carbonaceous slug loads defeat nitrification — heterotrophs outcompete autotrophs for dissolved oxygen at the floc scale, and diffusion into larger flocs raises the bulk concentration the liquid has to hold to keep the floc interior aerobic.
Community composition is influent-specific and only partly steerable: Enhanced biological phosphorus removal depends on polyphosphate-accumulating organisms taking up volatile fatty acids anaerobically and storing phosphorus aerobically. Glycogen-accumulating organisms consume the same substrate and remove no phosphorus, and the competition is reported to be sensitive to temperature, pH and the composition of the available carbon. Sidestream processes are harder again: partial nitritation–anammox on dewatering liquor requires out-selecting nitrite-oxidising bacteria from a reactor deliberately operated to retain even slower-growing anammox biomass, using some combination of retention-time control, dissolved oxygen setpoint, transient anoxia and free ammonia or free nitrous acid inhibition. Which combination holds on a specific liquor, at its temperature, conductivity and inhibitor content, is what published results do not settle.
None of this makes upgrade work R&D by default. Sizing an anoxic zone, selecting media and commissioning to a performance guarantee are established methods with outcomes determinable in advance. See what does not qualify.
What Separates a Plant Trial from Commissioning
Both involve a full-scale plant, instruments, samples and a report. The difference is what is unresolved when the work begins. Commissioning asks whether an installed design meets the basis it was sold on; the expected result exists on paper before anyone turns a valve. A trial asks a question whose answer changes what is known whichever way it lands — a hypothesis recorded before the experiment begins, measurable outcomes and evaluation criteria established in advance where appropriate, variables deliberately controlled so that observed effects can be assessed, and results capable of testing the hypothesis. Where the outcome could have been determined in advance from current knowledge, the activity is generally unlikely to be a core R&D activity on those facts, subject to the activity's own facts and the statutory tests.
Four record habits do most of the work on a live plant, and all of them are cheaper to build than to reconstruct (record keeping):
• Version the hypothesis, and date every version: A hypothesis may evolve during experimental work, provided the changes and their rationale are contemporaneously documented.
• Keep the runs that failed, in full: Two of the three configurations below produced no improvement, and they carry most of the knowledge. Deleting them removes the evidence that the outcome was not determinable in advance.
• Separate the sampling codes at the point of collection: Licence compliance samples and experimental samples often come out of the same tap on the same morning. If the laboratory register does not distinguish them, nothing downstream can.
• Decide the cost allocation basis before the season, not at lodgement: A plant that treats sewage while a trial runs on it incurs blower power, chemicals, laboratory work and operator hours for both purposes at once; a stated, contemporaneous basis for splitting them is worth more than a precise one invented later.
A Worked Example (Hypothetical and Illustrative Only)
Invented to show where the boundary falls. It is not a real project and says nothing about whether any actual claim would be accepted. It is deliberately scoped to nitrogen: phosphorus enters it as a constraint the nitrogen work must not break, and as a question consciously deferred — the reason is at the end.
It also says nothing about who could claim. Only an R&D entity can be entitled to the offset and, under s 355-35(3), an exempt entity cannot be an R&D entity — a point that comes up constantly in public-sector and council-owned water structures. Separately, s 355-210 requires the activities to have been conducted for that entity rather than, to a significant extent, for someone else, which turns on control, who bears the financial risk and who owns the results. Whether a particular body is an exempt entity, and which entity in a group is the R&D entity, are questions for the organisation's registered tax agent, and they are settled before any activity question is worth asking. We are not a registered tax agent and do not advise on them.
A regional South Australian council operates a 9,500 EP intermittently decanted extended aeration plant: two 1,200 m³ basins on a six-hour cycle, alum dosed for phosphorus, effluent to a creek in winter and to irrigation storage in summer. Flow is about 1.9 ML/d on processing days. A vegetable processing factory runs a May-to-September season, discharging about 150 kL/d at 6,500 mg/L COD and pH 5.8, with roughly 60% of the day's load arriving between 2 pm and 8 pm at shift change. Liquor temperature falls from about 21 °C in February to 12.4 °C in July. Illustrative licence conditions: ammonia-N ≤ 2.0 mg/L, total N ≤ 10 mg/L, total P ≤ 1.0 mg/L.
Baseline: Over the previous season, end-of-aeration ammonia-N ran at a 90th percentile of 4.8 mg/L and total N at 13.5 mg/L on processing days, against 0.9 and 8.1 mg/L in summer. Ex-situ batch tests at in-situ temperature put the maximum specific nitrification rate at 1.7 mg N/g VSS·h in July (12.4 °C) against 3.9 in February (21 °C). Dissolved oxygen, logged at two-minute intervals, fell to 0.4 mg/L through the evening slug against a 2.0 mg/L setpoint, with blower amps at their limit for 4.5 of the six hours — so the setpoint was never a live variable, and was held at 2.0 mg/L throughout. Nitrogen load averaged about 115 kg N/d on processing days.
What the desk work settled, and what it did not: Influent characterisation, respirometry, vendor correlations and a calibrated process model established that nitrifier inventory was ample at a 20-day solids retention time, and daily alkalinity balance closed. But they could not resolve: (1) the six-hour evening balance (demand ~285 kg CaCO₃ against acidic factory waste at pH 5.8); and (2) factory COD availability at 12.4 °C. July rate (1.7) sat ~20% below temperature expectation alone (2.2 mg N/g VSS·h), showing something else was binding that desk work could not predict.
Target, recorded 14 April 2026: Hold 90th percentile end-of-aeration ammonia-N ≤ 2.0 mg/L and total N ≤ 10 mg/L across processing season at liquor temp ≤ 13 °C on slug days, with no increase in blower capacity, no new basin volume, no change to alum dose, and diluted sludge volume index (DSVI) ≤ 150 mL/g.
Design & normalisation: Held: 6 h cycle, 20% decant fraction, 2.0 mg/L DO setpoint, alum dose, screening, 24 h composite sampling. Programme ran 154 days (14-day baseline + four 35-day blocks). Every specific rate was normalised to a 12.5 °C reference (1.07 coefficient).
Configuration A — Aerated fraction (55% → 75%): Measured DO during slug plateaued at 1.1 mg/L (blowers saturated). Total N rose to 16.2 mg/L, pH fell to 6.4, normalised rate fell to 1.5 mg N/g VSS·h. Ruled out: redistributing aerated time within installed capacity, as transfer during the six-hour window is binding, not duration.
Configuration B — Solids retention time (20 → 28 days): Raised solids from 4,500 to 6,300 mg/L (+40% inventory). Alpha factor fell from 0.55 to 0.42 (−24% transfer efficiency). Normalised rate remained 1.6 mg N/g VSS·h; DSVI rose to 185 mL/g, breaching total P (1.7 mg/L). Ruled out: added biomass as a route to peak capacity; confirmed July failure was not an inventory issue.
Configuration C — Factory stream as reagent in anoxic phase: 80% diverted through buffer into anoxic phase as electron donor for denitrification. Carbonaceous oxygen uptake during evening aeration fell by ~1/3, recoverable DO rose to 1.8 mg/L, internal alkalinity generation held pH at 6.9–7.1, normalised rate rose to 2.4 mg N/g VSS·h (+40%), closing season with 90th percentile ammonia-N of 1.3 mg/L, total N of 8.4 mg/L, DSVI 125 mL/g.
Block 4 — Return to baseline: Normalised rate fell back to 1.7 mg N/g VSS·h, confirming Configuration C caused the improvement rather than seasonal creek warming.
Deliberately deferred question & boundary: Testing anaerobic VFA feeding for biological phosphorus removal was deliberately excluded to avoid competing for the carbon needed in Configuration C. Candidate core activity spans the 4-block experimental period; infrastructure, PLC changes, and routine licence monitoring require separate supporting-activity analysis under s 355-30.
What Is Generally Unlikely to Be Core on Those Facts
Activity
Why
Sizing an anoxic zone or clarifier with standard design software and manuals
Established method, outcome determinable in advance
Commissioning a purchased MBBR or MABR package to its performance guarantee
Demonstrates a design basis that already predicts the result
Routine licence compliance sampling and the annual return
Activity associated with complying with statutory requirements — paragraph (f)
Weekly process monitoring on a standing schedule
Within paragraph (f) only where the monitoring is associated with complying with a statutory requirement or standard; otherwise assessed against the core test on its own facts
Retuning a plant inside a vendor's documented operating envelope
Applying a documented product as designed
Where an RSP Fits
An RSP is a scientific or technical service provider registered in specific research fields that a company can engage to conduct R&D activities on its behalf (business.gov.au). Ignition Research is registered in environmental engineering (ANZSRC 4011). On a treatment plant that work sits upstream of the trial: framing the unknown as a testable hypothesis, choosing load cases that represent the real failure mode rather than the average day, fixing the normalisation basis before the season rather than after it, and building the observation record while the plant runs.
Who can claim at all comes first, and in this sector it is not a formality — s 355-35(3) means an exempt entity cannot be an R&D entity, and that question belongs with a registered tax agent before anything technical is worth discussing. Where an eligible R&D entity is doing the work, one threshold point is worth knowing: RSP-conducted eligible R&D activities can be claimed even where the usual $20,000 R&D expenditure threshold is not met, and using an RSP does not guarantee eligibility — you still self-assess. In mechanism, under s 355-100(2), where an entity's total notional R&D deductions for the year fall below $20,000, the offset is instead worked out on a substituted base made up of eligible expenditure incurred to a registered research service provider that is not an associate, for services within a field for which it is registered, together with any CRC contributions. Offset tiers are covered in our article on the refundable and non-refundable offset; see also claiming R&D under $20,000 and R&D Tax Incentive in Adelaide.
Talk to Ignition Research before the season starts, while the trial can still be designed as a trial. As a Registered Research Service Provider at Lot Fourteen in Adelaide, we assist with experimental design, technical R&D work and contemporaneous supporting records within the research fields for which we are registered. We are not a registered tax agent: your organisation self-assesses and remains responsible for its own claim. Get in touch.
Frequently Asked Questions
Q: Is upgrading a wastewater treatment plant for nutrient removal an eligible R&D activity?
A: Generally not, as a core R&D activity, where the upgrade applies established design methods to a known influent — a mass balance, a sizing calculation and commissioning to a vendor guarantee have outcomes a competent process engineer can determine in advance. A core activity may exist in the narrower case where no established basis predicts whether a given intensification will hold the limits on a particular influent under a particular load or temperature regime, and that can only be determined by a systematic progression of work based on principles of established science, proceeding from hypothesis to experiment, observation and evaluation, and conducted to generate new knowledge. You self-assess.
Q: Why can't the response be predicted from the literature or a simulation model?
A: Process models are calibrated rather than predictive from first principles. Their kinetic and stoichiometric parameters — maximum growth rates, half-saturation constants, the readily biodegradable fraction of influent COD, the alpha factor for oxygen transfer — are fitted to a specific mixed liquor and influent, and the parameters that matter most under stress are often the least transferable. A model and the published record together will usually narrow the range of plausible outcomes, and both should be run before any plant is touched. The question the statutory test asks is whether what remains after that narrowing can still only be resolved by experiment.
Q: Is EPA licence compliance monitoring a core R&D activity?
A: Generally unlikely, on those facts and subject to the activity's own circumstances. Section 355-25(2)(f) excludes activities associated with complying with statutory requirements or standards, including routine testing and analysis, from being core R&D activities. That does not turn on whether the individual result is known in advance — it is not — but on the activity being undertaken in connection with demonstrating compliance. Additional instrumented sampling designed specifically to answer an experimental question is a different activity, assessed on its own facts, and whether it qualifies as supporting depends on s 355-30, including the dominant-purpose test in s 355-30(2).
Q: Can a sidestream deammonification retrofit be R&D if the process already runs overseas?
A: The test looks at whether the outcome can be determined in advance on the basis of current knowledge, information or experience — worldwide knowledge, not the company's. That a process exists elsewhere weighs against novelty in general, but it does not by itself resolve whether a specific dewatering liquor, at its temperature, alkalinity, conductivity and inhibitor load, will allow nitrite-oxidising bacteria to be out-selected while retaining anammox biomass. Where published results and vendor experience genuinely do not settle that, and it can only be resolved by a systematic progression of work, a core activity may exist. Where a vendor supplies a design basis that predicts the result, it generally does not.
Sources & Further Reading
legislation.gov.au — Income Tax Assessment Act 1997 — Div 355, incl. ss 355-25, 355-30, 355-35, 355-100 and 355-210
waterquality.gov.au — Guidelines for sewerage systems (National Water Quality Management Strategy)
waterquality.gov.au — Default guideline values for water quality
waterquality.gov.au — Australian guidelines for water recycling
dcceew.gov.au — National Pollutant Inventory: total nitrogen
Related: environmental engineering research field · what does not qualify · what an RSP is · refundable vs non-refundable offset · R&D Tax Incentive in Adelaide · more Insights
This article is general information from a Registered Research Service Provider about the R&D Tax Incentive. It is not tax, legal or financial advice; eligibility depends on your circumstances and you should self-assess and seek your own advice.
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