Question 4 of 7: Consulting Engineering Advice — Air Toxics, Sustainability and LCA

Question 4: Consulting Engineering Advice — Air Toxics, Sustainability and LCA (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) PM10 Particulates and Ambient Air Standards

My advice is to attack PM10 mass emissions at the source rather than manage them by dilution. Fit best-available control technology — a fabric-filter baghouse or electrostatic precipitator sized for the plant's actual particle-size distribution — on every significant point source, and pair it with fugitive-dust controls (material enclosure, conveyor covers, water sprays on unpaved haul roads) so uncaptured emissions are also reduced. Install continuous emissions/opacity monitoring so exceedances are caught in near-real-time rather than at the next stack test, and build a formal air-quality management plan that tracks mass emission rate against the applicable CCME Canadian Ambient Air Quality Standard for PM10/PM2.5. A taller stack for greater dispersion is not an acceptable substitute: it lowers ground-level concentration without lowering total mass emitted, which is inconsistent with both the regulator's mass-based limits and sustainable practice.

(ii) Sustainable Development in Metal Mining

Meeting industrial demand for copper and iron while protecting future generations means applying the three pillars of sustainable development — economic, social and environmental — across the mine's full life. I would advise: (1) progressive, concurrent reclamation of disturbed land as mining advances, rather than deferring all reclamation to closure, so the environmental liability never grows unmanageably large; (2) dry-stack or filtered tailings management in place of a conventional wet tailings pond, which materially reduces the risk of a tailings-dam failure and its long-term water-quality legacy; (3) investment in ore-processing efficiency (energy and water intensity per tonne of metal) to extend the resource's economic life and reduce footprint per unit of output; and (4) early and ongoing consultation and benefit-sharing with local and Indigenous communities, consistent with the Canadian Impact Assessment Act framework, so the social pillar is not an afterthought. Supporting secondary (recycled) metal supply alongside primary production also reduces the long-run virgin-ore extraction rate needed to meet demand.

(iii) Life Cycle Analysis for a Pharmaceutical Plant

To stay both profitable and environmentally "green," I would advise a full cradle-to-grave life cycle assessment of the plant's products — raw-material extraction and synthesis, formulation, use, and end-of-life — to locate the environmental hotspots, which in pharmaceutical synthesis are typically solvent use and the associated hazardous-waste treatment/disposal cost. Applying green-chemistry principles at those hotspots (higher atom-economy synthetic routes, safer/lower-volume solvents, catalytic rather than stoichiometric reagents, and closed-loop solvent recovery) cuts environmental impact and raw-material/waste-disposal cost at the same time, so pollution prevention pays for itself rather than trading off against profitability. Formalizing this under an ISO 14001 environmental management system gives the owners a structured way to track performance improvements over time and demonstrate due diligence to regulators and customers, turning the LCA from a one-time study into a continuous-improvement tool.