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18-Env-A1 Principles of Environmental Engineering · December 2019

Question 4 of 7: Population, Economic Growth and Energy Use as Causes of Environmental Pollution

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 4: Population, Economic Growth and Energy Use as Causes of Environmental Pollution (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)–(iii) Environmental Impacts and Engineering Solutions by Growth Driver

Economic growth, population growth and increased energy use each stress air emissions and water demand through different mechanisms, which is why the six-cell comparison below is useful: it forces a distinct, concrete pair of impacts and matching engineering solutions for each intersection rather than one generic answer for “growth.”

2 impacts & 2 solutions, by growth area
2-Impacts & 2-Solutions(i) Economic Growth(ii) Population Growth(iii) Energy Use
Air Emissions Impacts: expanded industrial and manufacturing output raising point-source combustion and process emissions (SO2, NOx, VOCs, particulates); rising freight and commercial-vehicle activity supporting the growing economy.
Solutions: mandatory best-available-control-technology (BACT) emission standards tied to new/expanded industrial permits; low-emission freight/logistics incentives and modal shift to rail.		 Impacts: rising aggregate vehicle-km travelled and residential heating emissions as population grows; increased open-burning/waste-related emissions where collection infrastructure lags growth.
Solutions: transit-oriented development and vehicle-emission standards to limit per-capita transport emissions; mandatory tie-in to managed waste collection/disposal to eliminate open burning.		 Impacts: increased combustion emissions (SO2, NOx, particulates, CO2) from expanded fossil-fuel generation; localized air-quality degradation near new/expanded generating stations.
Solutions: flue-gas desulfurization and selective catalytic reduction at new/expanded plants; a shift in generation mix toward lower-emission sources (hydro, wind, natural gas in place of coal).
Water Demand Impacts: expanded industrial process-water withdrawals competing with municipal/agricultural users; increased commercial and manufacturing water consumption tied to output growth.
Solutions: mandatory industrial water-recycling/closed-loop process design as a permit condition; tiered industrial water pricing to incentivize efficiency as output grows.		 Impacts: rising total potable-water demand outpacing existing supply/distribution capacity; increased pressure on shared aquifers or surface sources as more households draw from the same system.
Solutions: tiered/increasing-block water pricing and mandatory low-flow fixtures to curb per-capita demand; phased capacity expansion of supply and distribution infrastructure tied to population projections.		 Impacts: large cooling-water withdrawals for thermal power generation competing with other users; lowered river/lake levels or groundwater tables near withdrawal points during peak demand.
Solutions: closed-loop (recirculating) cooling systems in place of once-through cooling to cut withdrawal volumes (see Problem 3(iii)); water-use permitting with withdrawal caps tied to environmental-flow requirements.