Milestone map
Milestone map
3 milestones
Characterise a pollutant source and select control strategy
2–3 weeks (source research + technology comparison + report writing)
Identify a real or published air pollution control scenario (industrial stack emissions, vehicle exhaust, indoor air quality, or fugitive dust) and characterise the pollutant source: pollutant type (particulate, gaseous, or both), concentration range, flow rate, and regulatory limit applicable in your jurisdiction (e.g. UK Clean Air Act limits, EU Industrial Emissions Directive, US EPA NAAQS). Using this characterisation, evaluate at least two candidate control technologies (e.g. electrostatic precipitator, fabric filter, scrubber, catalytic converter, biofilter) against the removal efficiency required, capital cost order-of-magnitude, and operating conditions. Justify your technology selection with quantitative reasoning. If direct measurement is unavailable, use published emission factors or EPA AP-42 emission data.
Proof required
Submit a source characterisation and technology selection report (600–800 words) with: pollutant source description and characterisation data (citing source — measured or AP-42); applicable regulatory limit; comparative evaluation of two control technologies against efficiency, cost, and operating conditions; and your justified technology selection decision.
What gets checked
- Pollutant characterisation is quantitative — concentration (mg/m³ or ppm), flow rate (m³/s or m³/hr), and the specific regulatory limit cited by source document, not generic air quality goals
- Technology comparison uses numerical removal efficiency requirements — 'scrubber B achieves 95% removal vs. 88% required' not 'it works well'
- Technology selection justification addresses at least two technical criteria beyond cost alone — efficiency, energy consumption, maintenance burden, or operating temperature are all valid criteria
Common mistakes
- Selecting a real scenario but using only qualitative descriptions of pollutant sources — the characterisation must include numerical data; a report without flow rates and concentration values cannot support quantitative sizing in M2
- Evaluating technologies based on general descriptions rather than published performance data — efficiency claims must cite specific sources (manufacturer specifications, EPA RBLC, literature values)
Resources
Foundationstart here
Depthgo deeper
Masteryfor the dedicated
What a verifier looks for
- Source characterisation must be quantitative — concentration range with units, flow rate with units, and regulatory limit with citation. A qualitative description does not meet the Engineering Design Triad's analysis artifact requirement.
- Technology comparison must use numerical efficiency data — check that removal efficiencies are cited from a source document, not asserted from general knowledge.
- Technology selection must be justified against multiple criteria — a selection based on cost alone or efficiency alone is an incomplete engineering decision.
- The Proof Accessibility Rule applies — EPA AP-42 and RBLC are free and publicly accessible; the student does not need proprietary software to complete this milestone.
- Reviewer should be an environmental engineer, air quality specialist, or process engineer with pollution control experience — 'an engineer' without domain specificity is not sufficient.
Size the selected control equipment and calculate performance
2–3 weeks (calculation development + checking)
Using the source characterisation from Milestone 1 and the selected control technology, perform quantitative equipment sizing calculations to determine the key design parameters for the control system. Required calculations depend on the technology selected: for a fabric filter — filtration velocity (m/min), total filter area (m²), and pressure drop estimate; for a wet scrubber — liquid-to-gas ratio (L/m³), scrubber diameter, and mass transfer unit calculation; for an electrostatic precipitator — specific collecting area (m²/m³·s⁻¹) via Deutsch-Anderson equation; for a biofilter — empty bed residence time (EBRT) and bed volume. Show all calculation steps with units. If using a tool, the setup and results must be shown, not just the output.
Proof required
Submit your sizing calculation set (handwritten or typed) showing: the design basis (flow rate, inlet concentration, target outlet concentration); each calculation step with formula, substituted values, and units; final design parameters with a sanity check against published guidelines or typical operating ranges. Free tool acceptable: EPA APTI Air Pollution Training (online), PetroWiki (open access), or Python/Excel with shown formula logic.
What gets checked
- All calculations carry units through every step — a number without units at any intermediate step fails the engineering quality standard
- Final design parameters are checked against a published typical range — e.g. 'filtration velocity of 1.2 m/min is within the typical 0.6–2.4 m/min range for pulse-jet fabric filters (EPA AP-42)' demonstrates engineering judgment
- The calculation set is traceable from design basis to result — someone else could independently verify every step without asking the student for clarification
Common mistakes
- Presenting only the final equipment size without showing calculation steps — 'filter area = 45 m²' with no derivation is a result, not an engineering calculation
- Using an online sizing tool as a black box and reporting its output — tools are acceptable as a check, but the student must show the underlying calculation independently; tool output alone is AI-fakeable
Resources
Foundationstart here
Depthgo deeper
What a verifier looks for
- Calculations must show all steps with units — reject any submission where units are dropped at intermediate steps or where only a final result is given.
- Technology-specific sizing method must be used — a scrubber sized with a fabric filter method, or vice versa, is a fundamental error that must be caught.
- Sanity check against published typical ranges is required — a design parameter outside the typical operating range must be explained, not just reported.
- Tool use is acceptable only if the student's own calculation is also shown — a tool output alone cannot be verified as the student's work.
- Reviewer must have process engineering or environmental engineering experience with the specific control technology — not general engineering knowledge.
Produce design specification and regulatory compliance assessment
2–3 weeks (specification + compliance assessment + reviewer meeting)
Compile a design specification for your selected and sized air pollution control system, and assess whether it meets the applicable regulatory emission limit from Milestone 1. The specification must cover: equipment summary (type, size, key parameters from M2); predicted outlet emission concentration and comparison to regulatory limit with a margin statement; pressure drop and energy consumption estimate; a maintenance schedule outline (frequency and type of inspection, filter replacement, or fluid replenishment); and one identified failure mode that could cause a compliance exceedance, with the monitoring indicator that would detect it. Present to a qualified reviewer (environmental engineer or process engineer with pollution control experience) for technical challenge.
Proof required
Submit: (1) your design specification document (500–700 words covering all five elements above); (2) a compliance assessment summary table (one row per regulatory limit — pollutant, limit, predicted outlet, margin, compliant/non-compliant); (3) a written record of the reviewer's technical challenge and your responses (200 words minimum).
What gets checked
- Compliance margin is quantified — 'predicted 18 mg/m³ vs. limit 50 mg/m³, 64% margin' not 'comfortably within limits'
- Failure mode analysis names the specific mechanism — 'broken filter bag → particulate breakthrough → PM₁₀ exceedance detectable by continuous opacity monitoring' not 'equipment failure'
- Reviewer challenge record shows genuine technical engagement — the reviewer asked about at least one specific design assumption (e.g. filter pressure drop estimation method, moisture content effect on filter performance) and the student's response addressed the assumption
Common mistakes
- Writing a compliance assessment that compares to a self-set target rather than the regulatory limit cited in Milestone 1 — the limit must be the external regulatory standard, not an internal design target
- Failure mode section that lists generic equipment failures without tracing the mechanism to a compliance exceedance — every failure mode must end with an emission consequence
Resources
Foundationstart here
What a verifier looks for
- Engineering Design Triad check: this outcome produces a design artifact (equipment specification), an analysis artifact (sizing calculations + compliance assessment), and a documentation artifact (specification document with failure mode analysis) — all three are present across M1–M3.
- Compliance assessment must compare to the external regulatory limit from M1 — not an internal target.
- Failure mode section must trace mechanism to emission consequence — a failure mode without an emission consequence is incomplete.
- Reviewer must be an environmental engineer or process engineer with air pollution control experience — a general engineering reviewer without this domain experience cannot meaningfully challenge the technical assumptions.
- Reviewer challenge record must show a genuine technical exchange — a record of the reviewer saying 'looks good' does not satisfy the adversarial verification element.
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