18-Env-A1 Principles of Environmental Engineering · December 2019
Question 5 of 7: Environmental Impact Assessment, Sustainable Development and Life Cycle Analysis
Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
Notes on this paper
National Exams — December 2019 — 18-Env-A1 / Principles of Environmental Engineering. 3 hours duration; closed book with a candidate-prepared 8.5×11 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.); Sawyer, McCarty & Parkin, Chemistry for Environmental Engineering and Science; Guidelines for Canadian Drinking Water Quality (Health Canada); Canadian Council of Ministers of the Environment (CCME) water-quality and municipal solid-waste guidelines; Canadian Environmental Protection Act, 1999 (CEPA) and Canadian Environmental Assessment Act (CEAA 2012); Bies & Hansen, Engineering Noise Control; Andrews, Canadian Professional Engineering and Geoscience (professional ethics).
Question 5: Environmental Impact Assessment, Sustainable Development and Life Cycle Analysis (20 marks)
(i) Environmental Impact Assessment for the Northern Alberta–to–West Coast Pipeline
An environmental impact assessment (EIA) reduces pollution by identifying, at each stage of the pipeline’s development, the specific environmental issue that stage creates and binding a concrete mitigating action to it before the stage proceeds — rather than assessing the project’s impact only once, after design is fixed:
EIA process steps, key issues and mitigating actions
Process step
Key issue
Action to address the issue
Route selection and baseline studies
Pipeline corridor crosses sensitive terrain — watercourses, wetlands, mountain passes, and traditional Indigenous territory across northern Alberta and British Columbia
Multi-criteria routing study avoiding designated sensitive/protected areas where feasible; baseline water-quality, fisheries and wildlife surveys; early and ongoing Indigenous consultation and traditional-knowledge input into route selection
Construction (right-of-way clearing, trenching, watercourse crossings)
Soil erosion and sedimentation of streams; habitat fragmentation and disturbance during clearing and trenching; spill risk during pipe-laying and hydrostatic testing
Erosion and sediment control plans (silt fences, staged revegetation); trenchless (directional-drilled) crossings at sensitive watercourses instead of open-cut; spill-contingency and hydrostatic-test-water management plans reviewed before construction begins
Operation (25+ year pipeline service life)
Long-term leak/rupture risk to soil, groundwater and salmon-bearing streams along the route; cumulative right-of-way maintenance disturbance
Continuous leak-detection monitoring and periodic in-line inspection (smart pigging); emergency response and spill-response planning coordinated with local/Indigenous communities; ongoing right-of-way revegetation and erosion monitoring
(ii) Three Principles of Sustainable Development Applied to a 25-Year Wind Farm
Sustainable development balances environmental, social and economic considerations over the project’s full life; applying three core principles to a wind turbine farm over a 25-year life cycle shows both where wind achieves sustainability strongly and where it does not automatically do so:
Inter-generational equity (meeting present needs without compromising future generations). Wind power displaces fossil-fuel generation and its associated greenhouse-gas emissions over the full 25-year operating life, directly serving this principle; however, true inter-generational equity also requires a credible end-of-life decommissioning and blade-recycling/disposal plan (turbine blades are largely composite material that is not yet widely recyclable), since leaving that burden to future generations would undercut the same principle the project claims to serve.
Resource efficiency and minimizing environmental footprint. Wind energy has no fuel-extraction or combustion footprint during operation and a comparatively small operational land disturbance (land between turbines often remains available for agriculture), scoring well on this principle; construction-phase impacts (foundation concrete, access roads, and any transmission-line right-of-way) and avian/bat mortality risk are the offsetting costs that must be actively managed (careful siting away from major migratory routes, curtailment during high-risk periods) rather than assumed away.
Precautionary principle and adaptive management. Because a 25-year commitment cannot fully anticipate future grid, technology or ecological conditions, sustainable practice requires ongoing environmental monitoring (bird/bat mortality, noise complaints, local ecosystem effects) throughout the operating life with a willingness to adapt operations (curtailment schedules, maintenance practices) as new information emerges — not a one-time impact assessment at commissioning treated as sufficient for the full 25 years.
On balance, wind power achieves the sustainability principle strongly on the emissions/resource-efficiency axis but only achieves it fully if end-of-life decommissioning and ecological monitoring are genuinely carried through the entire 25-year life cycle, not treated as an afterthought.
(iii) Life Cycle Analysis Steps Applied to Greenhouse Food Production
A life cycle analysis (LCA) evaluates a product or process’s environmental burden across its full life span rather than at a single point, and applying its standard steps to greenhouse food production directly targets the stated problems of fertilizer overuse and nutrient-rich wastewater generation:
Goal and scope definition, and inventory analysis (identifying and quantifying inputs/outputs). Defining the system boundary (from fertilizer/water/energy inputs through to harvested crop output and discharged wastewater) and quantifying every material and energy flow — including fertilizer application rates and the nutrient (N, P) load leaving in drainage water — makes the fertilizer-overuse and nutrient-wastewater problems explicitly visible and measurable rather than anecdotal, which is the necessary first step before either can be reduced.
Impact assessment (translating inventory flows into environmental impact categories). Converting the quantified nutrient discharge into impact categories such as eutrophication potential (for receiving water bodies) and resource depletion (for the fertilizer inputs themselves) lets the operation prioritize which flows matter most environmentally, rather than treating all inputs as equally significant.
Interpretation and improvement analysis (identifying and implementing reduction opportunities). This step converts the assessment into concrete operational changes — adopting precision fertigation (matching nutrient dosing to real-time crop uptake rather than a fixed schedule), closed-loop/recirculating irrigation to capture and reuse drainage nutrients rather than discharging them, and on-site treatment of any residual nutrient-rich wastewater before release — directly reducing both the fertilizer overuse and the nutrient-rich wastewater the question identifies as the greenhouse’s key issues.
