18-Env-A1 Principles of Environmental Engineering · May 2016
Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
National Exams — May 2016 — 04-Env-A1 / Principles of Environmental Engineering. 3 hours duration; closed book with an 8×11 in double-sided aid sheet; Casio or Sharp approved calculator only. Any five questions constitute a complete paper (first five answers marked); all seven are solved below for completeness. Each question is worth 20 marks.
Reference texts. Davis & Cornwell, Introduction to Environmental Engineering (6th ed.); Metcalf & Eddy, Wastewater Engineering: Treatment and Resource Recovery (5th ed.); MWH’s Water Treatment: Principles and Design (3rd ed.); Guidelines for Canadian Drinking Water Quality (Health Canada); Canadian Council of Ministers of the Environment (CCME) water-quality and landfill guidelines; Canadian Environmental Protection Act, 1999 (CEPA); Impact Assessment Act, 2019 (Canada); Andrews, Canadian Professional Engineering and Geoscience (professional ethics).
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.
An environmental impact assessment (EIA) systematically identifies, predicts and mitigates a project's environmental effects before approval and construction, so that pollution is designed out of the process rather than remediated after the fact. Applied to a gold-mine development, the EIA works through each major process step of the mine's life cycle, pairing the key issue that step raises with the mitigation action built into the project design and approval conditions:
| Process Step | Key Issue | Mitigation Action |
|---|---|---|
| Ore extraction (open-pit/underground mining) | Habitat/land disturbance; acid rock drainage (ARD) potential from newly exposed sulphide-bearing rock | Progressive/staged land disturbance; acid-base accounting to classify and segregate potentially acid-generating waste rock during mine planning |
| Ore processing (crushing, grinding, cyanide leaching/flotation) | Tailings-pond seepage of cyanide and heavy metals to groundwater; tailings-dam failure risk | Engineered, lined tailings storage facility with leak-detection monitoring; cyanide destruction (e.g., SO₂/air process) before any discharge; dam design and independent review to current Canadian Dam Association guidelines |
| Site closure and reclamation | Long-term (post-closure) ARD generation and continued loss of fish/wildlife habitat | Closure and reclamation plan with financial security (reclamation bond) posted before construction; perpetual water treatment where ARD cannot be eliminated; progressive revegetation with native species |
Framing these three steps through a formal EIA — rather than addressing pollution reactively once it occurs — is what lets the regulator (and the public, through the EIA's consultation process) require the mitigation actions as binding approval conditions before the mine is ever built, which is the core pollution-reduction value of the assessment.
The key principle of sustainable development, as commonly framed since the Brundtland Report, is meeting the needs of the present generation without compromising the ability of future generations to meet their own needs — balancing environmental, economic and social objectives simultaneously rather than optimizing any one of them alone.
Choosing solar energy as the renewable option: solar photovoltaic generation directly displaces fossil-fuel combustion, reducing greenhouse-gas emissions and local air pollutants over the operating life of the system, and the resource (sunlight) is inexhaustible on any human timescale, which strongly aligns with the environmental leg of sustainability. However, a genuine assessment of "to what degree" this achieves sustainability requires life cycle analysis (LCA) rather than looking only at the zero-emission operating phase: LCA accounts for the embodied impacts of raw-material extraction (silicon, silver, rare metals), panel manufacturing energy and emissions, transportation, installation, and end-of-life disposal or recycling of panels and inverters. A solar installation typically achieves an energy payback (the point at which cumulative energy generated equals the energy embodied in manufacturing it) within a few years of a 25–30 year service life, after which its lifetime net environmental benefit is strongly positive — but LCA also flags real sustainability gaps that operating-phase thinking alone would miss, such as end-of-life panel recycling infrastructure still being immature in most jurisdictions, and the resource/labour footprint of the rare-material supply chain.
Solar energy therefore substantially advances the sustainable-development principle on a full life-cycle basis, but "to what degree" is qualified rather than absolute: sustainability is best served by pairing solar deployment with deliberate end-of-life management (panel recycling/take-back programs) and supply-chain stewardship, which is precisely the kind of gap an LCA-informed design process is meant to surface before the project is built rather than after.
