Question 3 of 7: Life Cycle Analysis and Risk Management

Problem 3: Life Cycle Analysis and Risk Management (20 marks)

Question text not reproduced: the examination questions are © Engineers and Geoscientists BC. Open the official past paper (linked at the top of this page) to read the question, then follow the worked solution below.

[Figure not reproduced: Fig. 1 — The five-stage LCA chain given in the exam figure, with the Reuse-and-Recycle loop returning material from Disposal back into Formulating/Processing. See the official exam paper.]

(i) LCA business and environmental case. A representative example is a municipality's choice between single-use HDPE recycling totes and returnable, reusable collection totes for its blue-bin program. Extracting/harvesting virgin HDPE resin and manufacturing a new tote every few years is compared, stage by stage, against manufacturing a heavier-duty tote once and running it through repeated use-and-return cycles; the LCA totals the extraction, processing, manufacturing, use and end-of-life energy and emissions for both options rather than comparing only the two purchase prices.

From a business perspective the reusable option wins on total cost of ownership once the avoided repeat-purchase and disposal fees are counted over the tote's service life, even though its unit price is higher — the LCA is what makes that longer-horizon economics visible to a procurement decision that would otherwise default to lowest first cost. From an environmental perspective, the reusable tote's embodied energy is amortized over many more use-cycles, so its life-cycle greenhouse-gas footprint per collection event is materially lower even after accounting for the extra material and durability built into it; the Reuse-and-Recycle loop shown in the figure is what returns end-of-life totes to feedstock rather than to landfill, closing the loop the disposable option cannot.

Three areas that must be addressed for the LCA to be truly representative: (1) system boundary definition — deciding whether transport, tote washing/maintenance energy and end-of-life recycling credits are inside or outside the study boundary changes the answer materially; (2) functional unit selection — the comparison must be normalized to an equivalent unit of service (e.g. "one household's recyclables collected per year for 10 years") rather than "one tote," or the reusable tote's longer service life is not fairly credited; (3) data quality and allocation — using site-specific resin and energy-grid emission factors rather than generic global averages, and consistently allocating shared manufacturing-line impacts between products, per ISO 14040/14044.

(ii) Risk management analysis example. A representative example is a fuel-oil distribution terminal's environmental risk management program for its above-ground storage tanks sited near a municipal aquifer. RM analysis begins by identifying the credible failure scenarios (tank overfill, corrosion leak, pipeline coupling failure), then evaluates the consequence and likelihood of each against the aquifer's vulnerability, and from that ranking selects concrete mitigation strategies — secondary containment berms sized to 110% of the largest tank's volume, continuous leak-detection instrumentation, and a written spill-response plan with pre-staged containment equipment — rather than a single generic "be careful" policy.

Three areas that must be addressed in RM for a sustainable approach: (1) systematic risk identification and characterization — a documented hazard/failure-mode inventory specific to the facility, not a generic checklist, so the mitigation actually targets the pathways that matter here (e.g. the aquifer, not a receiving stream that doesn't exist on site); (2) a hierarchy-of-controls mitigation strategy — preferring elimination/substitution (double-walled tanks, leak-resistant couplings) and engineering controls (containment, automatic shutoff) over administrative controls and emergency response alone, since the latter only reduce consequence after a release has already begun; (3) ongoing monitoring, review and emergency preparedness — periodic tank integrity testing, updated risk registers as throughput or site conditions change, and a rehearsed emergency response plan, so the RM program remains valid rather than a one-time assessment that goes stale.