16-Civ-A3 Elementary Environmental Engineering · May 2017
Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
Paper format. National Exams, May 2017 — 16-Civ-A3 Elementary Environmental Engineering. Three hours; closed book with one candidate-prepared 8½ × 11 double-sided aid sheet; approved Casio or Sharp calculator only. Seven problems are printed, each worth 20 marks, and any five constitute a complete paper (maximum 100 marks). All seven are solved here, because the set is intended as a study resource rather than an exam script. Section marks are shown in brackets at the left margin of each question and are reproduced below.
Reference texts.
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.
Each cell below states two major environmental impacts and two corresponding engineering solutions for the intersection of a growth driver (columns) with an environmental medium (rows), assuming strict environmental limits must be met.
| Medium / Driver | (i) Population growth | (ii) Industrial expansion | (iii) Energy-use increase |
|---|---|---|---|
| Air emissions | Impacts: more vehicle traffic and home heating raise NOx/PM and CO2; urban smog. Solutions: transit-oriented planning and vehicle-emission standards; district heating and building-efficiency codes. | Impacts: stack emissions of SO2, NOx, VOCs and air toxics; fugitive dust. Solutions: baghouses/ESPs and scrubbers/thermal oxidisers; leak-detection and cleaner-process substitution. | Impacts: combustion CO2, SO2, NOx and PM from power generation. Solutions: shift to renewables/natural gas and demand-side efficiency; flue-gas desulphurisation and low-NOx burners. |
| Water demand | Impacts: higher per-capita withdrawal stresses source supply; lower low-flows. Solutions: metering with conservation pricing and leak reduction; water-efficient fixtures and reuse of greywater. | Impacts: large process-water withdrawals and thermal/contaminant discharge. Solutions: water recycling and closed-loop cooling; process optimisation to cut specific water use. | Impacts: once-through cooling withdrawals and evaporative losses at thermal plants. Solutions: dry/hybrid cooling and cooling-water recirculation; renewables that need little water. |
| Wastewater treatment | Impacts: higher sewage volume and nutrient load overloads plants; CSOs. Solutions: capacity expansion with nutrient removal; sewer separation and inflow/infiltration control. | Impacts: toxic/high-strength industrial effluent upsets biological treatment. Solutions: pretreatment/source control and permitting; dedicated advanced (physical-chemical) treatment. | Impacts: cooling blowdown and scrubber wastewater add salts/metals. Solutions: zero-liquid-discharge and metals precipitation; segregation and reuse of clean streams. |
Across all three drivers the recurring engineering strategy is the same in structure: reduce the load at source (efficiency, conservation, cleaner processes) first, then treat the residual to the required strict limit with the appropriate control technology. Because population, industrial and energy growth compound one another in a city, the solutions must be planned together — conservation lowers water and the wastewater and energy that move and heat it, so integrated demand management yields the largest environmental return.
