18-Env-B1 Environmental Assessment and Management Systems · May 2016
Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
Reference texts: Mihelcic & Zimmerman, Environmental Engineering: Fundamentals, Sustainability, Design; Davis & Cornwell, Introduction to Environmental Engineering (6th ed.); ISO 14001:2015, Environmental Management Systems — Requirements with Guidance for Use; ISO 14040/14044, Life Cycle Assessment — Principles and Framework; Canadian Environmental Protection Act, 1999 (CEPA); Impact Assessment Act, 2019 (Canada); World Commission on Environment and Development, Our Common Future (the Brundtland Report), 1987.
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) Three key EIA issues for a landfill serving a doubling population. 1. Capacity and siting sized to the ten-year-forward waste generation, not current tonnage. Cell footprint, liner area and final elevation must be designed against the projected doubled population's waste generation, since sizing to today's tonnage would force a costly, disruptive mid-life expansion (and a second round of impact assessment) well before the site's intended design life. 2. Leachate generation and groundwater protection at the larger scale. A doubled waste mass roughly doubles long-run leachate volume, so the EIA must confirm the liner, leachate collection and (if needed) treatment capacity are designed for the full ten-year-forward loading, not retrofitted piecemeal as tonnage grows. 3. Haul-route and buffer-zone compatibility with the community that is itself growing. Because the same population growth driving landfill demand is also expanding residential development around the site, the EIA must assess whether the truck haul route and buffer/setback distances remain adequate against the community's projected footprint ten years out, not just its current extent.
(ii) Three engineering methods to improve or reduce wet-weather treatment bypasses. 1. Real-time control (RTC) of in-line and off-line storage. Sensors and automated gates/pumps actively route peak wet-weather flow into interceptor storage or dedicated storage tanks and release it back to the plant after the peak passes, equalizing the flow the plant actually has to treat rather than letting the full storm peak arrive at once. 2. Green infrastructure and low-impact development (LID) in the combined sewershed. Bioswales, permeable pavement and detention practices upstream reduce the peak stormwater volume entering the combined system in the first place, directly shrinking the flow that can trigger a bypass. 3. High-rate wet-weather treatment trains. A parallel high-rate process (e.g., ballasted flocculation with disinfection) sized specifically for flows above the plant's normal secondary-treatment capacity treats the excess flow to a much higher standard than an untreated or minimally treated bypass, even though it is not full secondary treatment.
(iii) Technical and non-technical particulate-emission solutions near a residential community. Technical solution. Install a fabric-filter baghouse (or wet scrubber, depending on particle characteristics) on the process exhaust stream, capturing fine particulate before it reaches the stack and reducing the emitted mass loading directly at the source. Non-technical solution. Adopt an operational/administrative control — scheduling the dustiest process campaigns away from times of peak community exposure (e.g., avoiding early-morning releases when temperature inversions trap ground-level particulate), maintaining a vegetative buffer/screening zone, and running a community air-quality monitoring and complaint-response program that lets residents' observations trigger an operational review.
