18-Env-A1 Principles of Environmental Engineering · May 2018
Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
National Exams — May 2018 — 04-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 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.
Urbanization, rising energy use and industrialization each stress noise, water demand and wastewater treatment through different mechanisms and at different scales, which is why the nine-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 | (i) Urbanization Growth | (ii) Energy Use Increase | (iii) Industrialization Growth |
|---|---|---|---|
| Noise Pollution | Impacts: increased road-traffic and construction noise near expanding residential areas; loss of natural vegetative buffers that previously attenuated ambient noise. Solutions: noise barriers/berms along arterial roads and transit-oriented land-use setbacks from major noise sources; noise bylaws with construction-hour and equipment-noise-limit enforcement. |
Impacts: added noise from new/expanded generating stations, transformers and cooling equipment; increased traffic noise associated with fuel/material delivery to energy facilities. Solutions: acoustic enclosures and vibration-isolated mounts on generating and cooling equipment; siting new energy infrastructure with adequate setback/buffer distance from residential receptors. |
Impacts: continuous process, ventilation and material-handling noise from new/expanded plants; heavy-vehicle traffic noise from freight movement. Solutions: acoustic enclosures/silencers on process equipment and mandated maximum property-line noise limits in the operating permit; scheduling/routing controls for heavy-vehicle traffic away from sensitive receptors. |
| Water Demand | Impacts: rising per-capita and total potable-water demand outpacing existing supply/distribution capacity; increased impervious surface reducing natural aquifer recharge that helps sustain the supply. Solutions: tiered/increasing-block water pricing and mandatory low-flow fixtures to curb per-capita demand; low-impact development (LID) and green infrastructure to sustain groundwater recharge as the urban footprint grows. |
Impacts: large cooling-water withdrawals for thermal power generation competing with other water 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; water-use permitting with withdrawal caps tied to environmental-flow requirements. |
Impacts: large new process/cooling-water withdrawals stressing local supply; competition between industrial and municipal/agricultural users for the same water source. Solutions: mandatory water-recycling/closed-loop process-water systems within the facility; water-use permitting and allocation planning that reserves a minimum environmental flow ahead of new industrial withdrawals. |
| Wastewater Treatment | Impacts: rising aggregate flow and organic/nutrient loading to municipal treatment plants as population grows; increased impervious area driving combined-sewer-overflow (CSO) frequency and hydraulic overload at the plant. Solutions: staged capacity expansion and tertiary nutrient-removal upgrades ahead of projected growth; separation of combined sewers or CSO storage/treatment facilities, paired with distributed stormwater detention (LID) to reduce peak flows reaching the collection system. |
Impacts: thermal (heated) cooling-water discharge and, for some generation types, ash-pond/scrubber-wastewater streams requiring specialized treatment. Solutions: cooling towers/ponds or a diffuser outfall to control thermal discharge (see Problem 4(iii)); dedicated ash-pond/scrubber wastewater treatment (settling, chemical precipitation) before discharge or recycle. |
Impacts: higher-strength or novel industrial process wastewater exceeding municipal sewer-use bylaw limits; risk of upset to biological treatment from shock industrial loads or toxic constituents. Solutions: mandatory industrial pretreatment programs before sewer discharge, sized to the specific contaminant profile; on-site treatment trains and continuous effluent monitoring for facilities discharging directly to the environment. |
