Question 5 of 7: Life Cycle Analysis Schematic; Environmental Risk Assessment Process

Problem 5: Life Cycle Analysis Schematic; Environmental Risk Assessment Process (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.

(i) Four key LCA stages (ISO 14040/14044 framework) and general purpose. LCA's general purpose is to quantify the full cradle-to-grave environmental burden of a product or process — raw-material extraction, manufacturing, use and end-of-life — so that engineering decisions are made on total life-cycle impact rather than on the impact visible at only one stage (e.g. the manufacturing plant's own emissions, ignoring the upstream material or downstream disposal burden).

The four stages: 1. Goal and Scope Definition — defines the study's functional unit, system boundary and intended application, fixing what is being compared and over what boundary before any data is collected. 2. Life Cycle Inventory (LCI) Analysis — compiles the mass and energy inputs/outputs (raw materials, energy, emissions, waste) at every stage within the defined boundary. 3. Life Cycle Impact Assessment (LCIA) — translates the raw inventory data into impact-category indicators (global warming potential, eutrophication, resource depletion) using characterization factors, converting a long inventory list into a small number of interpretable impact scores. 4. Interpretation — runs iteratively throughout the study (not just at the end), checking the completeness, sensitivity and consistency of the goal/scope, inventory and impact-assessment stages and drawing conclusions and recommendations.

Engineering example — comparing a single-use PET bottle to a refillable glass bottle for a beverage bottler. A goal-and-scope-only comparison (bottle material mass alone) would favour the lighter PET bottle. A full LCA instead reveals two environmental advantages of the refillable system: 1. Lower cradle-to-grave greenhouse-gas footprint per litre delivered. Once the LCI accounts for the glass bottle's ~20–30 reuse cycles (washing energy and transport included), its per-fill embodied-manufacturing and end-of-life impact is far lower than repeatedly manufacturing and landfilling/recycling a new PET bottle for every fill. 2. Reduced marine/terrestrial plastic-waste generation. Because the LCIA impact-category results include a solid-waste/plastic-persistence indicator alongside global warming potential, the refillable system's near-elimination of single-use plastic waste shows up as a distinct advantage that a carbon-footprint-only comparison would have missed entirely — precisely the kind of blind spot LCA's multi-category impact assessment is designed to catch.

(ii) Four key ERA processes and an example justifying the Harvard Business Review statement.

1. Hazard identification. Systematically identify every credible source of environmental harm in the operation (chemical storage, process upsets, transport, storm-driven overflow) before any single hazard is prioritized. 2. Risk analysis and characterization. Estimate each hazard's likelihood and consequence (a small leak vs. a full tank rupture reaching a watercourse) to rank hazards by actual risk rather than by visibility or ease of fixing. 3. Risk control and mitigation. Implement engineered and administrative controls sized to the characterized risk — secondary containment, high-level alarms, spill-response procedures — targeting the highest-ranked risks first. 4. Monitoring and review. Continuously track control performance (containment integrity checks, incident metrics, groundwater monitoring) and feed findings back into a repeated Hazard Identification step as operations, inventory or surrounding land use change.

Engineering example. A chemical distribution terminal storing bulk solvents near a residential neighbourhood applies the cycle: it identifies tank overfill and secondary-containment bypass during a storm as its principal hazards; analyses that a full tank rupture reaching the storm sewer and a nearby creek is low-probability but high-consequence; implements high-level overfill alarms and containment sized to 110% of the largest tank as controls; and monitors containment integrity and groundwater quality on a schedule that feeds back into re-identifying hazards as new solvents are added to inventory. The terminal experiences zero uncontrolled releases over a multi-year operating period following adoption of the program — directly demonstrating the Harvard Business Review statement, since the same structured risk management that protects the neighbouring creek and community from contamination also protects the company from the cleanup cost, regulatory penalty and reputational damage a release would cause, creating the "positive operating environment" the quote describes.